Assstment of Gloves

The Assessment of Medical Gloves for In-Situ
Applications
Daniel Preece
A thesis submitted in partial fulfilment of the requirements for the degree of

Doctor of Philosophy
The University of Sheffield

Faculty of Engineering
Department of Mechanical Engineering
Submission Date
1st February 2021
i
Abstract
Medical examination gloves are used worldwide and are one of the most common personal
protective equipment (PPE) used. The polymers used to develop these gloves undergo rigorous
testing to ensure they meet the requirements for use. Primarily, these tests assess the barrier
integrity and tensile properties. The effects of placing a membrane over the hand, however, has
been shown to be detrimental to the successful performance of tasks carried out by the wearer. The
extent of this reduced performance is unknown, but any reduction in tactility and/or dexterity could
be disadvantageous to patient care. It could also impact PPE compliance, causing users to remove
gloves for certain tasks. As such, this research introduces a range of test methodologies for donning
and doffing gloves, as well as assessing how friction is modified with the introduction of
contaminants that are encountered when gloves are worn.
In order to effectively assess glove performance, the environments gloves encounter, which
have received little attention in previous studies, should be carefully considered and replicated as
closely as possible. The aim of this thesis is to investigate the effects of gloves on users when they
are used in-situ Test protocols were developed to cover three key performance areas: donning and
doffing, glove contamination, and dexterity. Manual performance tests were set up using readily
existing dexterity and sensitivity tests (Purdue pegboard and a simulated tactile (bumps) test). To
better understand donning and doffing, friction assessments were conducted to assess the
tribological interactions between the skin and the inner surface of glove materials, having
undergone different treatments. The friction assessments were repeated for interactions between
the outer surface of glove materials and objects with textures that replicated typical hand and tool
interactions, both in dry and simulated contamination conditions (water, mucus, blood and other
bodily fluids).
Three key stages of the donning process were identified (preparation, hand insertion and
manipulation), and in all stages, moisture was found to significantly complicate the donning process,
as the gloves stuck to the hands more frequently. In wet-hand conditions, polymer coated latex
gloves were quicker to don and had lower friction than chlorinated gloves. In addition, nitrile gloves
were manufactured specifically for this project, looking at different thicknesses and chlorination
treatment strengths. Chlorinating nitrile gloves at 2000ppm appeared to be more beneficial for
donning. Doffing was found to be similar regardless of the material, condition, or thickness.
The gloves that produced stiffer tensile material samples were found to reduce friction and
reduce the dexterity performance of the glove users. When gloves were contaminated, friction was
found to be greatly reduced when compared to the dry condition. This reduction in friction was
greater for latex, which decreased the gross dexterity and sensitivity of the user. Smaller reductions
in friction were observed overall with nitrile, combined with an improvement in dexterity and
sensitivity. A synthetic blood was also developed and validated for the tribological properties to
circumvent the need for use of animal blood in future friction assessments.
Knowledge of which physical properties affect which key performance area is fundamental
to manufacturers. Optimising the combination of these properties (within other constraints such as
cost, constituent availability, and ecological impact) will improve task performance, increasing user
satisfaction, and ultimately, PPE compliance and patient safety.
ii
Acknowledgements
My sincere thanks go to Professor Matt Carré and Professor Roger Lewis for their support and
feedback over the last four years. Thank you for putting up with my everchanging project design, my
dynamic nature, and understanding my approach to this project.
I would also like to thank my industry sponsors at Synthomer, Simon Bassett, Peter Shaw
and Paul Brooks, for their continued understand of the changing paths of the project, and feedback
on the work conducted. In addition, I extend a great thanks to Thian Hong Ng and Heam Kit Tong in
the Group Technical Centre in Malaysia for hosting me, training me in the labs, touring me around
manufacturing plants, and helping guide the project with valuable feedback, as well as provision of
materials and expert advice. Moreover, a massive thank you to Zhenli Wei, for meticulously reading
through this thesis and providing expert feedback.
I would also like to extend an, albeit random, thank you to my secondary school science
tutors. Kathryn Casey and Adrian Symonds, you not only sparked my interest in science through your
admirable teaching, but enabled, and embraced, my critical thinking nature, which was crucial into
leading me to this point. Thank you very much.
It would also be negligent of me if I did not thank the people, who supported me through
this Ph.D., mostly by distracting me, or allowing me to distract them. Natalie, Zing, John, Rob,
Diyana, Raman, Olivia, and Hamzah, thank you. Without you listening to me grumble about statistics,
working on different projects with me, or the full scale distracting conversations about nothing, I do
not think I would have made it through some of the tougher days. Included in that is Jamie Booth,
who managed to get me what I needed, help with experimental designs, and provided much needed
perspectives on the project. Individually, you all made this Ph.D. experience much better than I ever
thought it could be, and I will relish the memories, and hopefully there will be many more to come.
And lastly, but definitely no means least, I give thanks to my wonderful wife Emily Preece.
She has read this thesis, and my work over the years, again and again. Without her support I would
not be where I am. The last four years would not have been possible, and I would not have the
ambition I have today, without the encouragement from my wife, my in-laws, and my family.
A massive thank you to everyone who was involved in my life for the last four years and
helped me on this journey.
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Contents
Abstract ....................................................................................................................................... ii
Acknowledgements..................................................................................................................... iii
Contents ..................................................................................................................................... iv
List of Tables ................................................................................................................................ x
List of Figures............................................................................................................................ xiii
Abbreviations ............................................................................................................................ xx
Glossary of Terms ......................................................................................................................xxi
Declaration ............................................................................................................................... xxii
Chapter One: Introduction ........................................................................................................... 1
1.1 Motivation of research................................................................................................................. 1
1.2 Aims of research ........................................................................................................................... 3
1.3 Novelty and Impact ...................................................................................................................... 4
1.4 Structure of thesis ........................................................................................................................ 5
Chapter Two: Literature review .................................................................................................... 8
2.1 Introduction .................................................................................................................................. 8
2.2 Medical glove use ......................................................................................................................... 8
2.3 Glove Materials and market trends ............................................................................................. 9
2.4 Glove Manufacturing ................................................................................................................. 11
2.4.1 Manufacturing Process ........................................................................................................ 11
2.4.2 Post-dip processing .............................................................................................................. 12
2.5 Glove Standards ......................................................................................................................... 14
2.6 Medical glove assessments ........................................................................................................ 15
2.6.1 Tactile Sensitivity ................................................................................................................. 15
2.6.2 Dexterity............................................................................................................................... 22
2.6.3 Grip and friction ................................................................................................................... 27
2.6.4 Double gloving ..................................................................................................................... 33
2.6.6 Durability .............................................................................................................................. 35
2.7 Size and fit .................................................................................................................................. 36
2.8 Paper grading ............................................................................................................................. 36
2.9 Conclusions ................................................................................................................................. 38
Chapter Three: Questionnaire .................................................................................................... 39
3.1 Introduction ................................................................................................................................ 39
iv
3.2 Aim and scope ............................................................................................................................ 40
3.3 Methodology .............................................................................................................................. 40
3.3.1 Questionnaire ...................................................................................................................... 40
3.4 Results ........................................................................................................................................ 42
3.4.1 Respondent roles ................................................................................................................. 43
3.4.2 Glove materials .................................................................................................................... 43
3.4.3 Contaminants contacted ...................................................................................................... 44
3.4.4 Perceived issues with NRL and NBR gloves .......................................................................... 48
3.4.5 Perceived issues with contaminated gloves ........................................................................ 49
3.4.6 Further issues ....................................................................................................................... 51
3.5 Discussion ................................................................................................................................... 53
3.6 Questionnaire limitations .......................................................................................................... 55
3.7 Conclusions ................................................................................................................................. 56
Chapter Four: Donning and doffing ............................................................................................. 57
4.1 Introduction ................................................................................................................................ 57
4.2 Aim and scope ............................................................................................................................ 58
4.3. Materials and Methods ............................................................................................................. 59
4.3.1 Glove materials and characterisation .................................................................................. 59
4.3.2 Donning methodology ......................................................................................................... 63
4.3.3 Questionnaire ...................................................................................................................... 64
4.3.4 Friction ................................................................................................................................. 65
4.3.5 Data Analysis ........................................................................................................................ 67
4.4 Results ........................................................................................................................................ 68
4.4.1 Glove properties .................................................................................................................. 68
4.4.2 Glove size and fit .................................................................................................................. 70
4.4.3 Donning and doffing ............................................................................................................ 72
4.4.4 Gloves sticking incidence ..................................................................................................... 75
4.4.5 Perception of fit, donning and doffing ................................................................................. 76
4.4.6 Friction ................................................................................................................................. 77
4.5. Discussion .................................................................................................................................. 83
4.5.1 Donning and friction ............................................................................................................ 83
4.5.2 Doffing.................................................................................................................................. 87
4.5.3 Glove properties .................................................................................................................. 88
4.5.4 Fit ......................................................................................................................................... 89
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4.6 Conclusions ................................................................................................................................. 89
Chapter Five: The effects of NBR glove properties on donning ..................................................... 91
5.1 Introduction ................................................................................................................................ 91
5.2 Aim and scope ............................................................................................................................ 91
5.3 Materials and methodology....................................................................................................... 91
5.3.1 Glove manufacture .............................................................................................................. 91
5.3.2 Experimental methodology.................................................................................................. 94
5.3.3 Analysis ................................................................................................................................ 96
5.4 Results ........................................................................................................................................ 96
5.4.1 Physical properties ............................................................................................................... 96
5.4.2 FTIR..................................................................................................................................... 101
5.4.3 Surface roughness .............................................................................................................. 102
5.4.4 Contact angle ..................................................................................................................... 102
5.4.5 Donning .............................................................................................................................. 103
5.4.6 Physical parameters to donning time ................................................................................ 107
5.4.7 Friction ............................................................................................................................... 111
5.4.8 Friction correlation to donning .......................................................................................... 119
5.5 Discussion ................................................................................................................................. 120
5.5.1 Physical properties ............................................................................................................. 120
5.5.2 Donning and friction .......................................................................................................... 122
5.5.3 Physical parameters ........................................................................................................... 125
5.6 Conclusions ............................................................................................................................... 126
Chapter Six: Dexterity and friction ............................................................................................ 129
6.1 Introduction .............................................................................................................................. 129
6.2 Aim and scope .......................................................................................................................... 130
6.3 Materials and methodology..................................................................................................... 130
6.3.1 Glove selection ................................................................................................................... 130
6.3.2 Physical property measurements ...................................................................................... 131
6.3.3 Task performance assessment ........................................................................................... 132
6.3.5 Friction methodology ......................................................................................................... 134
6.3.6 Data analysis ...................................................................................................................... 136
6.4 Results ...................................................................................................................................... 137
6.4.1 Physical characteristics ...................................................................................................... 137
6.4.2 FTIR..................................................................................................................................... 140
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6.4.3 Glove and hand size ........................................................................................................... 142
6.4.4 Dexterity............................................................................................................................. 145
6.4.4.1 Physical property correlation .......................................................................................... 149
6.4.5 Friction ............................................................................................................................... 150
6.4.5.1 Correlation to performance and glove stiffness ............................................................. 154
6.5 Discussion ................................................................................................................................. 155
6.5.1 Performance and friction ................................................................................................... 155
6.5.2 Physical properties ............................................................................................................. 159
6.5.3 Effects of gloves on dexterity ............................................................................................. 159
6.5.4 Glove size and fit ................................................................................................................ 162
6.6 Conclusions ............................................................................................................................... 165
Chapter Seven: Effects of contamination on glove friction ......................................................... 167
7.1 Introduction .............................................................................................................................. 167
7.2 Aim and scope .......................................................................................................................... 168
7.3 Materials and Methodology .................................................................................................... 168
7.3.1 Glove Material Selection and characterisation.................................................................. 168
7.3.2 Contaminant selection and characterisation ..................................................................... 169
7.3.3 Tool selection ..................................................................................................................... 171
7.3.4 Friction methodology ......................................................................................................... 172
7.3.5 Contaminant application.................................................................................................... 173
7.3.6 FTIR..................................................................................................................................... 176
7.3.7 Data and statistical analysis ............................................................................................... 176
7.4 Results ...................................................................................................................................... 176
7.4.1 Surface roughness and AFM of gloves ............................................................................... 176
7.4.2 Contaminant characterisation ........................................................................................... 183
7.4.3 Friction ............................................................................................................................... 185
7.5 Discussion ................................................................................................................................. 194
7.5.1 AFM and roughness profile ................................................................................................ 194
7.5.2 Friction and effects of tool patterns .................................................................................. 195
7.5.3 Contaminant interaction .................................................................................................... 197
7.6 Conclusions ............................................................................................................................... 204
Chapter Eight: Effects of contamination on dexterity and sensitivity ......................................... 206
8.1 Introduction .............................................................................................................................. 206
8.2 Aim and objectives ................................................................................................................... 206
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8.3 Materials and methods ............................................................................................................ 207
8.3.1 Participants ........................................................................................................................ 207
8.3.2 Glove selection and analysis .............................................................................................. 207
8.3.3 Dexterity measurements ................................................................................................... 208
8.3.4 Sensitivity measurement ................................................................................................... 210
8.3.5 Mucin and application ....................................................................................................... 211
8.3.6 Experimental procedure .................................................................................................... 212
8.3.7 Statistical analysis .............................................................................................................. 213
8.4 Results ...................................................................................................................................... 213
8.4.1 Mucin transfer.................................................................................................................... 213
8.4.2 FTIR..................................................................................................................................... 214
8.4.3. Gross dexterity (Purdue pegboard test) ........................................................................... 215
8.4.4 Fine dexterity (CSPDT) ....................................................................................................... 218
8.4.5 Sensitivity ........................................................................................................................... 220
8.5 Discussion ................................................................................................................................. 222
8.5.1 Binding of mucin ................................................................................................................ 222
8.5.2 Effects of mucin on dexterity ............................................................................................. 223
8.5.3 Friction and film formation ................................................................................................ 225
8.5.4 Effects of mucin on sensitivity ........................................................................................... 227
8.5.5 Significance of findings ...................................................................................................... 229
8.6 Conclusions ............................................................................................................................... 229
Chapter Nine: Blood friction and synthetic development .......................................................... 231
9.1 Introduction .............................................................................................................................. 231
9.2 Aim and Objectives .................................................................................................................. 232
9.3 Materials and methodology..................................................................................................... 233
9.3.1. Glove Materials ................................................................................................................. 233
9.3.2 Blood .................................................................................................................................. 233
9.3.3 Synthetic blood development ............................................................................................ 234
9.3.4 Properties of blood and synthetics .................................................................................... 235
9.3.5 Contact angles .................................................................................................................... 236
9.3.6 FTIR..................................................................................................................................... 236
9.3.7 Friction measurements ...................................................................................................... 237
9.3.8. Statistical analysis ............................................................................................................. 239
9.4 Results ...................................................................................................................................... 239
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9.4.1 FTIR..................................................................................................................................... 239
9.4.2 Material characterisation....................................................................................................... 241
9.4.3 Friction ............................................................................................................................... 247
9.4.3.1 NBR.................................................................................................................................. 247
9.4.3.2 NRL .................................................................................................................................. 250
9.5 Discussion ................................................................................................................................. 253
9.5.1 Whole human and citrated blood ...................................................................................... 253
9.5.2 Effects of blood on glove friction ....................................................................................... 253
9.5.3 Protein behaviour with gloves ........................................................................................... 256
9.5.4 Synthetic blood development ............................................................................................ 258
9.6 Synthetic blood validation ....................................................................................................... 259
9.7 Conclusions ............................................................................................................................... 261
Chapter Ten: Conclusions and future work................................................................................ 263
10.1 Importance of results for glove assessments ........................................................................ 263
10.2 Effects of glove properties ..................................................................................................... 269
10.3 Recommendations to industry .............................................................................................. 271
10.4 Future work ............................................................................................................................ 272
References............................................................................................................................... 274
Appendices .............................................................................................................................. 296
Appendix A – Publications ............................................................................................................. 296
Appendix B – Supplementary data for Chapter Four .................................................................... 297
Appendix C – Supplementary data for Chapter Five ..................................................................... 301
Appendix D – Supplementary data for Chapter Seven ................................................................. 317
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List of Tables
Table 2.1 Standards for medical examination glove testing, showing force at break (Fb),
elongation (Eb) and tensile strength (Ts).
Table 2.2 Studies relating to the effect gloves have on tactile sensitivity.
Table 2.3 Studies relating to the effect gloves have on the dexterity.
Table 2.4 Tools and equipment used in minor procedures to give an overview of the surfaces
and textures encountered.
Table 2.5 Finger and palm measurement sizes for selecting the best sized glove.
Table 3.1 Differences in response volume for issues between NBR and NRL gloves.
Table 3.2 Differences in response volume for issues between NBR and NRL gloves once
contaminated with substances indicated in Figure 3.4.
Table 4.1 Gloves used and thickness measurement.
Table 4.2 Measured physical properties of gloves.
Table 4.3 Measurements of gloves used in this study.
Table 4.4 Comparison of perceived best fit gloves used by participants to HSE glove size
recommendations from hand sizing (44).
Table 4.5 Results of ANOVA/Kruskal-Wallis test conducted across the total donning time, and
each step of the donning process in both dry and wet conditions.
Table 4.6 Post Hoc Tukey’s test results conducted on the total time in the dry condition.
Table 4.7 Results of paired t-tests comparing dry to wet in all glove types at each step of the
donning process.
Table 4.8 Findings of the chapter comparing the outcome of performance of the wet hand to
the dry hand condition.
Table 5.1 Components used to make compounded solution of the NBR material for the glove
film formation.
Table 5.2 Results of physical testing of the gloves under EN standards and calculated
stiffness.
Table 5.3 Tukey’s (HSD) test carried out on thinner gloves.
Table 5.4 Tukey’s (HSD) test carried out elongation at break.
Table 5.5 Tukey’s (HSD) test carried out on the stiffness of the glove samples.
Table 5.6 Results from surface roughness measurements of developed gloves.
Table 5.7 Total average time taken to don one glove with pick up time removed.
Table 5.8 Results of P-values obtained from paired t-tests between gloves in dry and wet
conditions at each stage of the donning process.
Table 5.9 Pearson correlation coefficient results for total donning time and the hand
insertion step against the physical parameters.
Table 5.10 Pearson correlation coefficient results comparing the stress at 100% strain and the
tensile strength of the samples.
Table 5.11 Correlation of donning time to stiffness of each of the samples at 100% strain at
the total donning time and each of the three stages of the donning process.
x
Table 5.12 Correlation of CoF to total donning time and hand insertion step in participant 1.
Table 5.15 Findings of the chapter comparing the outcome of performance of the wet hand to
the dry hand condition, with comments on the quickest glove to don.
Table 6.1 List of gloves and known constituents.
Table 6.2 Physical properties of gloves.
Table 6.3 Results of Tukey’s (HSD) test following ANOVA (p<.001) on the force at break.
Table 6.4 Results of Tukey’s (HSD) test following ANOVA (p<.001) on the tensile strength.
Table 6.5 Results of Tukey’s (HSD) test following ANOVA (p<.001) on the elongation.
Table 6.6 Results of Tukey’s (HSD) test following ANOVA (p<.001) on the calculated stiffness
at 100% strain.
Table 6.7 Post-hoc Dunn’s test results conducted after Kruskal Wallis on combined test
scores.
Table 6.8 No of pins dropped in the combined test.
Table 6.9 Post-hoc Dunn’s test results conducted after Kruskal Wallis on assembly test
scores.
Table 6.10 Number of pins dropped, and washers knocked off in the assembly test.
Table 6.11 Pearson’s correlation coefficients of measured physical parameters.
Table 6.12 Results of Tukey post-hoc test for all glove conditions at 1 N target load.
Table 6.17 Correlation of friction at each load to the dexterity performance scores.
Table 6.18 Correlation of friction to glove stiffness.
Table 6.19 Former sizes obtained from one former manufacturer.
Table 7.1 Contaminants selected for friction assessment.
Table 7.2 Tools used for analysis of frictional properties. Wavelength refers to the distance
between repeating parts of the pattern.
Table 7.3 Viscosity (η), density (ρ), and estimated film thickness (t) of fluid contaminants.
Table 7.4 Results of t-tests comparing CoFs of contaminants to the dry NBR glove at the
minimum (~1 N) and maximum (~5 N) normal forces.
Table 7.5 Results of t-tests comparing CoFs of contaminants to the dry NRL glove at the
minimum (~1 N) and maximum (~5 N) normal forces.
Table 7.6 Average friction coefficient values obtained from each tool with the different
contaminants used for the NRL and NBR gloves.
Table 7.7 Summary of frictional differences to the dry glove at 1 N load.
xi
Table 8.1 Tukey’s (HSD) test results for the different gloving conditions in the Purdue
pegboard combined hands result.
Table 8.2 Dunn’s post-hoc test results for the different gloving conditions in the CSPDT
results.
Table 8.3 Performance of mucin contaminated glove performance when compared to dry.
Table 9.1 Constituents of the SB solutions.
Table 9.2 Results of the properties of the synthetic bloods and blood.
Table 9.3 Paired t-tests, comparing the developed SB to the measured ovine density.
Table 9.4 Paired t-tests, comparing the developed SB to the measured ovine viscosities.
Table 9.5 Paired t-tests, comparing the developed SB to the measured ovine contact angles
as well as comparing the human to the ovine blood.
Table 9.6 Paired t-tests results of weight deposition between ovine blood and each synthetic
blood.
Table 9.7 Static CoFs obtained from SB7 and whole ovine blood with paired t-test results
with NBR contaminated gloves.
Table 9.8 CoFs obtained from SB2 and whole ovine blood with paired t-test results with NRL
contaminated gloves.
Table 9.9 Summary of synthetic bloods which have a similar CoF to blood on each of the
glove materials along with their properties.
Table 9.10 Summary of results comparing dry gloves to blood contaminated, and the SB which
replicates the frictional properties of blood across all loads and the 1 N target
force.
Table 10.1 Summary of methodologies and assessments used in the thesis along with key
findings and recommendations for future work
xii
List of Figures
Figure 1.1 Structure of thesis.
Figure 2.1 Glove use procedure policy. Recreated from NHS guidelines.
Figure 2.2 Structure of the polyisoprene monomer making up the NRL.
a) Structure of the butadiene (left) and acrylonitrile (right) monomers which form
Figure 2.3 the copolymer nitrile butadiene rubber (NBR). b) Most commonly used for glove
manufacturing is XNBR, which is formed upon the addition of acrylic acid.
Figure 2.4 Glove manufacturing process.
Figure 2.5 Glove formed on porcelain mould.
Monofilament test showing a range (2.83, 5.07 and 6.10 gauge) of nylon
Figure 2.6
thread thicknesses.
Two-point discrimination touch test. Point spacing numbers correspond to
Figure 2.7
mm of the two distinct points.
Figure 2.8 Purdue pegboard (46 × 30 cm).
Figure 2.9 Crawford small parts dexterity test (24 × 23 cm).
Figure 2.10 Grading of glove related papers to assess gaps in knowledge.
Figure 3.1 Respondents of questionnaire by job sector (n=172).
Figure 3.2 Gloves routinely worn by respondents (n=172).
Contaminants coming into contact with medical gloves used throughout the
Figure 3.3
various fields.
Figure 3.4 Liquid drugs and powders contaminating gloves as indicated by respondents.
Figure 3.5 Breakdown of all contaminants contacted by job sector.
Results obtained from questionnaire regarding issues perceived with NBR and
Figure 3.6
NRL gloves.
Results obtained from questionnaire regarding issues perceived with NBR and
Figure 3.7
NRL gloves once contaminated.
Diagram showing range of comments regarding specific issues with gloves.
Figure 3.8
‘Not stated’ indicates no specific material was given in the response.
Breakdown of the responses surrounding issues from the comment section of
Figure 3.9 the questionnaire. ‘Not stated’ indicates that no specific glove was given in
the response.
Breakdown of the responses regarding specific tasks affecting participants of
Figure 3.10 the questionnaire. Tasks have been split into two sections to show the two
main issues affected.
Glove selection used in this study. From left to right; chlorinated NRL; polymer
Figure 4.1
coated NRL; chlorinated NBR; and polymer coated NBR.
Figure 4.2 Depiction of areas of glove used for measurements.
xiii
Tinius Olsen TL-190 tensometer and b) Press-cut sample for EN standard
Figure 4.3
testing
Schematic of goniometer. The syringe deposits a measured drop onto the
Figure 4.4 substrate on the platform. This is then viewed via the viewing lens with sight
aided by the light behind.
Figure 4.5 Stretching device with glove attached.
Schematic of the equipment set-up for capturing the donning and doffing
Figure 4.6
process.
a) AMTI plate with glove attached, arrow shows the direction of finger travel,
and b) the direction of forces with the z force as the normal load, the y force is
Figure 4.7
the lateral (sideways) force across the plate and x is the force of the direction
of the finger being dragged along the glove.
Figure 4.8 MoistSense used to measure the moisture in participant’s skin.
Figure 4.9 Typical graph for determination of friction coefficient.
Figure 4.10 Contact angles of DI water on the inside of each glove.
Glove donning steps. (a) shows the preparation step, opening the glove, (b)
Figure 4.11 shows the hand insertion step and (c) shows the pulling of material down the
fingers to comfortably fit hands.
Average results of time taken to don the medical gloves broken down into the
Figure 4.12
three key tasks.
Figure 4.13 Average results of time taken to doff the medical gloves.
Map of the glove showing areas where sticking of the fingers/hand occurred
Figure 4.14
on the glove throughout the study.
Incidences of sticking in the different areas within all of the gloves shown in
Figure 4.15
Figure 4.14.
Responses of the participant questionnaire regarding the fitting of the gloves
Figure 4.16
and the ease of donning and doffing.
Figure 4.17 Average moisture per participant across the 4 gloves.
Average friction and the CoF of chlorinated and polymer coated NBR gloves
Figure 4.18
across all participants.
Example of the stick-slip induced by the rapid alternation between static and
Figure 4.19
dynamic friction
Average friction and the CoF of chlorinated and polymer coated NRL gloves
Figure 4.20
across all participants. Error bars denote standard deviation.
Interaction between different glove surfaces when water is introduced. NBR
Figure 4.21 brings the finger to the surface due to the polar nature, whereas NRL is repels
water, causing it to lubricate.
xiv
Friction of PC NBR gloves showing how the moisture changes in the wet
Figure 4.22 condition increase friction overtime as a sliding interaction with the glove
spreads moisture away from the finger surface in contact.
Figure 4.23 Rolling of glove on the back of the hand when donning.
Figure 5.1 NBR material coagulated on the former surface (covered by coagulant salts) to
form the wet NBR film.
Figure 5.2 Diagram of hands where measurements were taken.
Figure 5.3 Stress-strain curves of each in-house formed glove.
FTIR spectra of gloves A-H with major functional group differences highlighted
Figure 5.4
and labelled with corresponding functional groups.
Figure 5.5 Average contact angles of gloves with DI water.
Figure 5.6 Average skin moisture on the hands in dry and wet conditions.
Average time taken for each of the three donning steps to be completed for
Figure 5.7
one glove.
Correlation of tensile strength to the total donning time of the gloves in the
Figure 5.8
wet condition.
Correlation tensile strength to the ‘hand insertion’ step time of the gloves in
Figure 5.9
the wet condition.
Figure 5.10 Correlation of tensile strength to stress at 100% strain.
Correlation of stiffness at 100% strain with the preparation stage of the
Figure 5.11
donning process in the dry condition.
Figure 5.12 Results of moisture measurements for each participant in each glove test.
Friction graphs obtained from glove A (500ppm) in dry and wet conditions at
Figure 5.13
the 1 N target load.
Friction graphs obtained from the thin control sample (D) in dry and wet
Figure 5.14
conditions at the 1 N target load.
Figure 5.15 Glove stretching with finger and ‘snapping’ back.
Friction graphs obtained from glove sample E (500ppm) in dry and wet
Figure 5.16
conditions at the 1 N target load.
Figure 5.17 Average friction results from participants 1-3 with the thinner glove samples.
Figure 5.18 Average friction and CoF from participants 1-3 with the thicker glove samples.
Figure 5.19 1) thicker glove (F); 2) thinner glove (B).
Figure 6.1 Purdue pegboard test.
Figure 6.2 Assembly test construction.
Figure 6.3 AMTI plate with steel strip attached.
Figure 6.4 Surface roughness profile of steel strip.
Figure 6.5 Schematic of friction test set-up.
xv
Figure 6.6 Stress-strain of gloves
Figure 6.7 FTIR spectra obtained from NBR gloves. Differences are highlighted in red.
Figure 6.8 FTIR spectra obtained from NRL gloves and NRL gloves with filler.
Comparison of the length of gloves used and the length of the participants’
Figure 6.9
hands.
Comparison of the length of middle finger of the gloves used and the length of
Figure 6.10
participants’ middle finger.
Comparison of the palm span of the gloves used and the span of the
Figure 6.11
participants’ hands.
Comparison of the finger width of the gloves used and width of the
Figure 6.12
participants’ index fingers.
Distribution of recommended glove sizes amongst the participants based on
Figure 6.13
palm circumference and finger length measurements.
Normalised results (gloved score – bare hand score) of the combined test (left
Figure 6.14
hand, right hand and both hands) in the Purdue Pegboard test.
Normalised results (gloved score – bare hand score) of the assembly test of
Figure 6.15
the Purdue Pegboard test.
Pearson correlation graph of combined Purdue pegboard scores to the
Figure 6.16
stiffness parameter of the gloves used.
Figure 6.17 Friction and CoFs of different gloving conditions and no-glove condition.
Figure 6.18 Correlation of stiffness to the friction coefficient at 1 N (r=-.735).
Figure a shows the NRL glove fingertip, b shows NBR 6311 and c shows the
Figure 6.19
PVC.
Figure 6.20 Schematic of the glove-metal asperity contact
Pinch grip exhibited with pin grabbing and placement amongst the
Figure 6.21
participants.
Left: hand spanned without gloves. Centre: hand spanned with NRL. Right:
Figure 6.22
hand and spanned with PVC gloves.
Summary of chapter findings, showing the effects of the different materials on
Figure 6.23 dexterity. NRL with filler offers better dexterity, due to less restricted
movement.
Figure 7.1 Tool 2 affixed to the AMTI force plate.
Location of contaminant on finger (shown in green) to the interphalangeal
Figure 7.2
joint of the index finger.
Figure 7.3 Powder application to the finger pad.
AFM images of NBR glove showing height (a), amplitude error (b), and phase
Figure 7.4
(c) images.
xvi
AFM images of NRL glove showing height (a), amplitude error (b), and phase
Figure 7.5
(c) images.
Height (a) and phase (b) images of the outer side of the NBR glove section
Figure 7.6
showing the possible adsorption onto surface.
Height (a) and phase (b) images of the outer side of the NRL glove section
Figure 7.7
showing the possible adsorption onto surface.
Height (a) and phase (b) images of the inner side of the NBR glove section
Figure 7.8
showing the possible adsorption onto surface
Height (a) and phase (b) images of the inner side of the NRL glove section
Figure 7.9
showing the possible adsorption onto surface
Difference in NBR and NRL films when exposed to light. a) NBR, colour
Figure 7.10 correction +40 brightness, -40 contrast and +200% saturation and b) NRL, +30
brightness, -20 contrast and +400% saturation.
Figure 7.11 FTIR of NRL and NBR outer layers assessing for differences between scans.
Figure 7.12 AFM roughness profile of NBR glove section
Figure 7.13 AFM roughness profile NRL glove section.
Figure 7.14 Surface roughness (Sa) of NRL (a) and NBR (b) gloves.
Figure 7.15 Weight of contaminants deposited onto the gloves.
Figure 7.16 Contact angles of contaminants on the NBR and NRL material.
CoFs at the minimum (min) and maximum (max) normal forces applied with
Figure 7.17
the NBR gloves in dry and contaminated conditions with each tool.
CoFs at the minimum (min) and maximum (max) normal forces applied with
Figure 7.18
the NRL gloves in dry and contaminated conditions with each tool.
CoFs at the minimum (min) and maximum (max) normal forces applied both
Figure 7.19 NBR and NRL gloves. NBR is represented by straight lines, whereas NRL is
represented by dashed lines.
Deformation of gloves observed with tools. The lower stiffness of the NRL
means the material fills the gap, incurring more static friction. The NBR
Figure 7.20
material is stiffer and sits atop the close-gap tool pattern, incurring a lower
static friction.
NRL reaction with tools with low tread depth. Contaminants fill gaps easier as
Figure 7.21 repelled by the NRL material, this separates the glove from the surface,
decreasing friction.
Proposed representation of the attraction of charges between mucin-steel
Figure 7.22
and mucin-NBR and mucin-NRL.
Example of film development over time for a NRL glove with mucin applied,
Figure 7.23
sliding on steel.
Figure 8.1 CSPDT pins and collar test.
xvii
Bumps test bed developed by Mylon et al. (13) b) location and size of bumps
Figure 8.2
(µm).
Figure 8.3 Application of mucin to the glove materials.
Mucin adherence to medium and large sized NRL and NBR glove materials.
Figure 8.4
Error bars denote standard deviation.
Figure 8.5 Spectra of NBR and mucin contamination.
Figure 8.6 Spectra of NRL and mucin contamination.
Normalised (mucin contaminated score – dry glove score) scores of combined
Figure 8.7
Purdue Pegboard test.
Average number of pins dropped across the gloving conditions in the
Figure 8.8
combined test.
Normalised (mucin contaminated score – dry glove score) scores of assembly
Figure 8.9
Purdue Pegboard test.
Average number of parts dropped across the gloving conditions in the
Figure 8.10
assembly test.
Figure 8.11 Normalised (mucin contaminated score – dry glove score) time from CSPDT
Figure 8.12 Average number of pins dropped across the gloving conditions in the CSPDT.
Grooves horizontal to the board. a) bumps test bed. b) groove running across
Figure 8.13
between rows B and C, and c) groove running across row F.
Results of bumps sensitivity test showing the percentage (%) detection rates
Figure 8.14
at each bump size.
CoF of a) NBR and NBR with mucin; b) NRL and NRL with mucin on smooth
Figure 8.15
steel across a 1-5 N target load range.
CoF of a) NBR and NBR with mucin; b) NRL and NRL with mucin on tweezers
Figure 8.16
(tool 5) across a 1-5 N target load range.
a) Materials pulling when deformed to elicit tactile sensation b) mucin
Figure 8.17
allowing the material to glide over the bump.
Figure 8.18 Representation of the mucin quantity of NRL on the bumps test board.
a) Lancing device with protective head detached to reveal the lancet. b) blood
Figure 9.1
drawn from finger after pricking with the lancet device.
Figure 9.2 Application of solutions to the glove materials.
Figure 9.3 Blood deposited onto the finger.
FTIR spectra of the NBR gloves and gloves contaminated with ovine and
Figure 9.4
human blood.
FTIR spectra of the NRL gloves and gloves contaminated with ovine and
Figure 9.5
human blood.
Density of synthetic bloods and ovine blood. Opaque red band indicates
Figure 9.6
density range of blood in the literature.
xviii
Viscosity of synthetic bloods and ovine blood. Opaque red band indicates
Figure 9.7
viscosity range of blood in the literature.
Figure 9.8 Contact angles of synthetic bloods, ovine blood, and human blood.
Contact angles of a) NBR and b) NRL. The lower contact angle in NBR indicates
Figure 9.9 a surface with hydrophilic properties whilst the NRL indicates hydrophobic
with high contact angles, as observed with all of the synthetic bloods.
Amount of SB, and blood deposited onto the NBR and NRL glove materials.
Figure 9.10
Figure 9.11 Evaporation of blood from the surface of the NRL and NBR materials.
Normal and Horizontal force of the NBR glove contaminated with ovine blood
Figure 9.12
at the 4 N target load.
Static friction (a) and CoFs (b) for dry NBR gloves and NBR gloves when
Figure 9.13
contaminated with ovine blood on smooth steel.
Static friction (a) and CoFs (b) for dry NBR gloves when contaminated with
Figure 9.14
synthetic bloods and ovine blood on smooth steel.
Comparison of the Static CoF at the 1 N target load for SB7 and ovine blood on
Figure 9.15
smooth steel.
Normal and horizontal force of the NRL glove contaminated with ovine blood
Figure 9.16
at the 4 N target load.
Static friction (a) and CoFs (b) for dry NRL gloves and NRL gloves when
Figure 9.17
contaminated with ovine blood.
Static friction (a) and CoFs (a) for dry NRL gloves when contaminated with
Figure 9.18
synthetic bloods and ovine blood.
Comparison of the Static CoF at the 1 N target load for SB2 and ovine blood
Figure 9.19
with NRL.
Friction of blood and mucin over the 1-5 N load range with NBR (a) and NRL
Figure 9.20
(b).
Figure 9.21 Static CoF for blood and mucin at 1 N.
Figure 9.22 Behaviour of flour particulates under an increasing load.
Properties assessed in the thesis and how they link to the effects on the
Figure 10.1 gloves and the user performance as the property increases (e.g. thickness gets
thicker).
xix
Abbreviations
The following is a list of encountered abbreviations throughout the thesis:
ATR: Attenuated total reflectance
Cl: Chlorinated
cm: Centimetre
CoF: Coefficient of friction
CR: (poly)chloroprene
DI: Deionised
Eb: Elongation at break
Fb: Force at break
FTIR: Fourier transform infrared spectroscopy
HSE: Health and Safety Executive
K: Stiffness
min: Minutes
ml: Millilitre
mm: Millimetre
mPa-s: Millipascals second
N: Newtons
NBR: Acrylonitrile butadiene rubber
NHS: National Health Service
nm: Nanometres
g: Grams
cm: Centimetre
NRL: Natural rubber latex
PC: Polymer coated
phr: Parts per hundred rubber
ppm: Parts per million
PVC: Polyvinyl chloride
Ra: Roughness average
Sa: Surface roughness average
s: Seconds
SB: Synthetic blood
T: Thickness
t: Film thickness
Ts: Tensile Strength
η: Viscosity
ρ: Density
xx
Glossary of Terms
The following is a list of encountered terms used throughout the thesis:
Adsorbed: Substance chemically adhered to a surface of a material

Contact angle: The angle where a liquid meets a substrate, measured by a Goniometer
Covid-19: Contagious respiratory virus (also known as Sars-CoV-2)
Dexterity: Ability to manipulate objects with the hands
Doffing: The act of removing a glove
Donning: The act of putting on a glove
Glove Material: Specific material used to make the glove
Glove: Entire glove system
Hydrophilic: Attracts water
Hydrophobic: Repels water
Phalangeal: Relating to the finger
Proximal: Closer to the body
Standard Deviation: Spread of data, used when averaging repeat measurements
Standard Error: Error from the mean, used when combining and averaging participant performance
data to show confidence in the mean.
Stiffness: A systems (e.g. glove) or materials (e.g. nitrile) resistance to deformation when load is
applied
Wettability: Preferences of a liquid to sustain contact with a surface, determined by affinity
between the materials
Whole Blood: Blood with all components, and no anti-coagulants added
xxi
Declaration
I, the author, confirm that the Thesis is my own work. I am aware of the University’s Guidance on the
Use of Unfair Means (www.sheffield.ac.uk/ssid/unfair-means). This work has not previously been
presented for an award at this, or any other, university.
Work published from this thesis can be found in the Appendix (A).
xxii
Chapter One: Introduction
1.1 Motivation of research
The purpose of medical examination gloves is to act as a first line of personal protective equipment
(PPE) for the hands to protect from contamination. For instance, clinical staff, such as doctors and
surgeons are required to don medical gloves to protect themselves and patients from pathogens.
Once manufactured, the industry looks very closely at assessing whether these gloves are good
enough to act as a barrier. However, there is relatively little research oriented towards how these
gloves affect the performance the user. This Ph.D. research is sponsored by Synthomer, a global
supplier of aqueous polymers, who supply nitrile glove polymers to leading glove manufacturers (1).
Predicted to raise to £6.1 billion in the 2020 global market, up from 7.2% in 2017, the medical glove
industry dominates the market in PPE. Driving factors around this increase in market value are the
stringent regulations in clinical settings, personal care, sanitation and any situations where
contamination of the skin may be an issue (2). The demand for gloves has increased due to the surge
in the SARS-CoV-2 (covid-19) pandemic, as gloves are worn more frequently, and changed more
often (3). Generally, three types of medical glove exist: examination, surgical, and chemotherapy.
The work conducted in this thesis focussed on one type of medical glove, examination, as these are
most commonly used. Chemotherapy gloves are thicker, to prevent radiation penetrating rapidly to
the skin. Surgical gloves are similar to examination gloves, but they exist in more precise sizing and
are said to offer better tactile sensitivity. These are also made more durable, for prolonged periods
of use (4, 5). Glove manufacturers and material suppliers (such as Synthomer) are the two industries
that are key to the development of medical gloves and share the same goal; to improve user
compatibility and performance of medical gloves, whilst maintaining or potentially saving costs.
Therefore, the main aim of this work is to understand the effects gloves have on users when they are
replicating the conditions they encounter when in use.
Research into the glove materials by these industries focuses on streamlining processes, and the
generation of new glove polymers. This has led to the expansion of non-latex polymers, such as
nitrile butadiene rubber, popular due to the characteristics being similar to that of natural latex.
Furthermore, the increased use of synthetics curtails the likelihood of adverse reactions to the
gloves due to rising latex allergies. The market trends now lean more towards these non-latex
alternatives, with nitrile being the most common examination glove being developed (2). New
techniques and processes facilitate an alteration in the chemistry of the butadiene rubber, allowing
different gloves to be created. These gloves are an improvement on the younger generations of
nitrile, offering better mechanical properties or different chemical resistant capabilities. However, as
1
these glove materials change, it is unknown if the effects they have on user performance changes.
Understanding how the differences in material parameters affect different aspects of glove use will
allow Synthomer, and polymer chemists, to develop gloves that can be manufactured for specific
purposes (e.g. improved dexterity). It may be worrying to think that what is seen as first line defence
PPE, could contribute to a reduction in health care capability, and a rise in misdiagnoses. However,
this may be the case (6–9).
Although little work exists looking at the impact of gloves on the performance, the World Health
Organisation estimates there is between a 0.005-0.02% chance of having equipment retained after
surgery (10). Conversely, studies have stated that the risk is much higher, around 12.5% (11). Most
commonly, the equipment is small items such as sponges, scissors, and pins. However, measuring
devices, scopes and even instruction manuals have been found in people after surgeries. It is
unknown as to how this occurs. It is suggested the hastiness of some surgeries affects the judgement
of the surgeon (10). However, surgical work requires tactile exploration in order to identify areas in
the body. It is just as possible that same tactile sensation that allows them to feel the body, has
failed to allow the identification of foreign objects (6, 7, 12). Although examination gloves are not
used in surgeries, this is indicative that problems exist, and in the wider context, examination gloves
are more routinely used than surgical gloves. Another example of this is highlighted in a study by
Jones, Friend, Dreher, et al. (13) who found that of 3225 patients, 510 may have had their prostate
cancer missed upon manual exploration. It is not possible to conclude that the gloves are the cause
of this, but it is reasonable to assume that the gloves may have dampened sensitivity, possibly
leading to misdiagnosis in some of these cases. The underlying theme of both the retained
instruments and the missed prostate cancer is that the tactility and dexterity, vital for the tasks, may
have been impinged by the use of gloves. Studies have shown gloves affect sensitivity, and in some
instances, dexterity is also affected, which could lead to poor patient care (6, 12). In addition, many
of these studies do not consider the situations gloves will be used in, and are studied in a dry,
uncontaminated condition. The understanding of how these gloves both interact with these
contaminants, and how the performance (task, protection, ease of use) is affected, is also not well
researched in the literature. Therefore, there is a requirement for assessments that replicate the
conditions in which gloves are used, to fully assess the effects of various properties on glove
performance.
2
1.2 Aims of research
The aim of this research is to improve how medical examination gloves can be assessed in a way that
replicates their use in working environments, as opposed to previous work where simplistic testing
was used to assess the effects of gloves on the user. The understanding gained from these
assessments can then inform manufacturers how the use of different glove polymers, and
treatments, will affect the performance of tasks carried out when wearing gloves, including the
donning and doffing process. The research in this thesis can then be oriented at both filling the gaps
in knowledge and making the assessments more applicable to manufacturers, such as Synthomer. In
order to do that, the thesis explores the manufacturing of these medical gloves, and the differences
present between them. The objectives of this thesis are as follows:
• To review the literature published on the assessment of medical gloves and liaise with
industry to understand the assessments being conducted under the standardised testing.
There is a requirement to identify unexplored areas in current literature by the way of a
paper grading. This allows for identification of how previous research can be made more
applicable, to replicate representative working conditions.
• To gain knowledge of where the user issues lie with gloves through the use of
questionnaires. In conjunction with this, knowledge of what the gloves are used for will
allow a more targeted approach for understand the contaminants gloves encounter when
being used. This will be conducted thought the use of surveys to understand the perception
amongst common examination glove users.
• Understanding the tribological interactions between gloves and a variety of surfaces is

salient, and seldom studied (6). Furthermore, assessing how these tribological interactions
are altered by the presence of contaminants, such as blood and powders, are important, as
this altered friction could cause issues with equipment being dropped/slipping out of the
hands. In addition, it is possible that in medical examinations, where gloves are required,
information that is received through the haptic interface could be missed (13). Thus,
assessing how contaminants affect glove friction, and ultimately, performance is explored in
this thesis using common contaminants (mucus, oil, blood, water, disinfectant, and powder),
informed from everyday glove users. This allows for an assessment of the effects
contaminated gloves have on friction and the performance parameters of glove users.
• The interaction between gloves and skin has received little attention in the literature. The
donnability of gloves is of a great research interest to the manufacturing industry, as
3
different coatings applied to the inside of gloves are said to produce different results in
terms of ease of donning (14–16). Development of methodologies to assess donning and
doffing will help investigate how different coating and treatments impact the user
experience. In addition, the differences in frictional properties can be highlighted and linked
to the physical parameters of the materials. From this, an understanding of the fundamental
skin-polymer interactions can be gained, which can inform manufacturers and glove users on
glove selection and development.
• The chemistry of medical gloves is well understood in the glove industry, allowing the
patented formations of nitrile to be developed and used for film formation by the raw
material manufacturers. Knowledge of how these chemical changes affect the glove
performance in terms of tensile properties and puncture resistance are studied and
recognised in the industry. However, the linking of the changes in chemistry, and ultimately
physical changes, to the performance has had little exploration, and requires investigation.
By using gloves of the same core materials, but with different additives or treatments, the
effects of gloves on donning, sensitivity, dexterity and friction can be understood. In
addition, the thesis focuses on the replicability of these tests, and putting them into industry
as an assessment method. This understanding can then inform manufacturers of which
physical properties of the gloves affect the end performance of glove users.
1.3 Novelty and Impact

The research conducted in this thesis offers new methodologies for assessing glove performance
from an ergonomic and tribological viewpoint. By obtaining information from glove users about their
perceived issues with gloves, the research was tailored to replicate the conditions gloves encounter
when in use. The applicability of tests to the conditions they are used in is lacking in the literature,
rendering some of the work obsolete, and incomparable. Thus, the assessments conducted in this
thesis, draws focus on the needs of the users, in order to make the research relevant to the everyday
problems, and aims to be suitable for adoption by industry. In some cases, the assessments may not
induce repeatable tests in industries (such as the donning of gloves), without further refinement, but
the research can give insight into how the gloves affect user performance. The research conducted
throughout this thesis has led to multiple research outputs including publications (Appendix: Section
A) and several industry presentations, including to glove material manufacturers, and glove
manufacturing plants in Malaysia. The originality of the thesis takes a fresh approach on the work
industry normally conducts, linking their mechanical tests, and chemical development, to the impact
4
gloves have on users in-situ. Finer details on the novelty and impact can be found in Chapter 10,
Section 10.1.
1.4 Structure of thesis

This thesis is organised into ten chapters that address the key aspects of the research. These are also
set out in Figure 1.1.
Chapter 1 gives an overview of the issues which drive the need for the research and the novelty and
impact of the work conducted. In this chapter, the aims and objectives of the thesis are also
described.
Chapter 2 provides insight into how gloves are manufactured, processed, and assessed. The review
also provides an evaluation of the present understanding of how medical examination gloves have
been assessed in the literature, and the need to incorporate the conditions gloves are used in, to
fully understand the tribological properties of gloves.
Chapter 3 investigates where research should be focused, by asking participants who use medical
examination gloves to provide answers on how gloves affect their performances, and what
contaminants they are likely to encounter in their profession.
Chapter 4 focuses on the inner side of the gloves, which is the ‘donning side’. The effects of different
glove materials and different finishing coatings/treatments are assessed for their donnability and
doffability, along with assessments of how the frictional properties change between the glove
coatings and treatments.
Chapter 5 closely follows the protocols developed in Chapter 4, looking at the donning of medical
examination gloves. However, this chapter looks gloves that have been formed ad-hoc, to assess the
frictional properties of different thicknesses and chlorination treatments. The chapter also aims to
link the performance to the mechanical and chemical nature of the gloves.
Chapter 6 looks into the differences in the physical and chemical properties of commercially
available gloves and evaluates the frictional performance in relation to dexterity performance. Also
discussed in this chapter are issues around fit, and how differences in manufacturing processes, may
affect the glove users’ experiences.
Chapter 7 explores the frictional interactions with different surfaces and contaminants, which are
found throughout the clinical sector. Furthermore, analysis of the chemical changes that may occur
in gloves is also explored.
5
Chapter 8 investigates how performance parameters, such as dexterity and sensitivity, is affected
when medical examination gloves are contaminated with mucus.
Chapter 9 concentrates on the development of synthetic blood surrogates for use in future studies.
Validation of the bloods is carried out by tribological assessments with whole ovine blood.
Chapter 10 concludes the work by summarising the key findings from the previous chapters, with
industry recommendations, and discussing the future work needed.
6
Figure 1.1. Structure of thesis
7
Chapter Two: Literature review
2.1 Introduction
The safety performance of medical examination gloves is relatively undisputed. However, it has yet to
be determined as to how gloves should be assessed for quality of purpose. Does placing a membrane
over the hand have such an effect on performance that a medical professional cannot perform tasks
correctly? This review aims to bring together the knowledge available on how medical glove
performance has been assessed within the literature. Firstly, focusing on the varied materials of gloves
before discussing how gloves have been assessed in previous studies. The advantages and limitations
of such assessments will be discussed, and suggestions will be made on improvements if and where
applicable. As the review is focusing on glove use in-situ, studies focusing on sensitivity, dexterity,
friction, grip, and performance perception will be evaluated.
2.2 Medical glove use

The purpose of medical gloves is to prevent the hands from becoming contaminated, or to avoid
contaminating a surface or patient. There is a general consensus in the literature, and in guidelines,
as to when gloves should be donned. The use of gloves in a clinical setting is based on a risk
assessment of the overall task. This risk assessment takes into account the chances of contact with
bodily fluids such as blood; broken skin; excretions; secretions and hazardous chemicals/drugs (17–
19). It is generally accepted that gloves are not necessary when administering vaccine injections
unless broken skin is present on either parties or there is anticipated exposure to bodily fluids (20).
The National Health Service (NHS) provides a standard operating procedure for all glove use,
although this differs slightly between trusts. For example, the Lincolnshire trust avoids the use of
natural rubber latex gloves whereas the Hampshire trust requires participation by users in a skin
monitoring programme (21, 22).
Expert opinion appears to be at the forefront of the decision as to when to wear either
surgical gloves or examination gloves to carry out minor surgeries. Medical examination gloves are
recommended for oral care; cannulation, blood exposure, rectal/vaginal examinations and many
minor procedures (21–24). It could be argued that, as minor surgery is still surgery, surgical gloves
should be donned. Nevertheless, outside of an operating theatre, medical examination gloves are
the primary gloves used. Figure 2.1 shows a list of procedures carried out using medical examination
gloves in the NHS (23).
8
Figure 2.1. Glove use procedure policy. Recreated from NHS guidelines (23).
Nursing Times Magazine published an article on what gloves to wear and when, stating that the NHS
uses only sterile examination gloves for aseptic procedures and minor surgery (25). Many studies
have been carried out assessing whether gloves used should be sterile or non-sterile (26–29), all of
which conclude that gloves do not need to be sterile in minor procedures as the risk of infection is
low and contamination of gloves is rare. However, it is recommended for sebaceous cyst excisions
that sterile examination gloves be worn. With the outbreak of covid-19 leading to a pandemic, the
NHS recommends gloves are worn by all clinical staff, for any contact with a patient (30, 31).
2.3 Glove Materials and market trends

The properties of gloves are dependent upon the raw manufacturing materials, manufacturing
processes followed, and the chemical treatment gloves receive. Natural rubbers are commonly used,
the most prominent being natural rubber latex (NRL), a substance found in the bark of Hevea trees
(32). NRL is known as a homopolymer, a repeating unit of the single monomer 1,4-cis polyisoprene as shown
in Figure 2.2 (33). By nature, the material is a highly deformable elastomer, allowing easy conformation
to the shape of the hand (14).
Figure 2.2. Structure of the polyisoprene monomer making up the NRL.
9
The Center for Disease Control (CDC) estimates that up to 6% of the worldwide population has a latex
allergy (34). Furthermore, the increasing incidence in NRL allergies means that alternative glove
materials must be used where appropriate. Other glove materials include nitrile butadiene rubber
(NBR), polyvinyl chloride (PVC) and polychloroprene (CR) (35, 36). The most common alternative
material to NRL is NBR, synthetically created using a copolymer of acrylonitrile and butadiene (Figure
2.2). However, the elastic loading response of NBR means that the conformability to the hand is
perceived to be inferior than that of NRL (7). The stiffness of NBR gloves is an issue for some, as they
report it hinders their ability to carry out tasks (7, 36). Different grades and generations of NBR have
been developed over time to accommodate various properties and manufacturing processes. The
most common is the carboxylated NBR (XNBR). XNBR gloves have a carboxyl group (COO-) introduced
from acrylic acid, which is added to the acrylonitrile and butadiene (Figure 2.3). This allows for ionic
cross-linking with zinc during glove formation, allowing for more improved physical properties such as
tensile strength and lower stiffness (37).
a) b)
Figure 2.3 a-b. a) Structure of the butadiene (left) and acrylonitrile (right) monomers which form the
copolymer nitrile butadiene rubber (NBR). b) Most commonly used for glove manufacturing is XNBR, which
is formed upon the addition of acrylic acid to the monomers shown in a (37).
Due to the prevalence of rising latex allergies, shifts have been evident in the market with regards to
medical glove use. NBR can be manufactured to a thinner gauge, thus trends over time have seen
gloves decrease in thickness from a standard of 0.1 mm to around 0.05 mm (38). This uses less
material, which has reported benefits for the end users, such as a greater tactile sensitivity, allowing
a greater sense of feeling (39–41). In addition to this, thinner gloves mean cheaper costs for
manufacturers, as less material is used. The manufacture of NRL gloves, requires the latex to be
sourced, tapped, and transported. This is added labour and time costs for manufacturing plants. As
NBR, CR and PVC are synthetic, there is no need for any additional labour costs to obtain natural
ingredients (39). The relaxation of the EN standard for force at break (9 N to 6 N) has also allowed
manufacturers to make NBR gloves of a thinner gauge (38, 42). However, challenges are presented
with this for manufacturers, finding materials that meet the specification of a break force of 6 N at
10
0.05 mm proves difficult. This has led to the development of multiple generations of NBR materials
over the years, each with different chemical and mechanical properties (38, 43).
2.4 Glove Manufacturing

The final glove product performance is influenced by many factors in the glove manufacturing
process, including difference in chemicals used at each stage, raw materials and the differences in
manufacturing methods (14, 38). In the first instance, the raw glove materials need to be
compounded with other materials to help control the glove development process. These
compounded materials contain not only the core glove material (such as NRL), but a variety of
accelerators, activators, cross linkers, vulcanising agents and anti-ageing additives are also added,
which will affect the overall end product (14). With the rising cost of materials, gloves are sometimes
bulked out with filler materials to extend their yield. NRL liquid contains a mixture of the rubber
suspension, sugars, resins and proteins, whereas synthetics (NBR, PVC, CR) requires polymer
emulsification to create the raw material (38). This takes place by mechanical shearing of the
monomers making up the NBR polymer compound. The process allows for particle size, structure,
and shape to be controlled. The particle size of the synthetic latex matrices (NBR) tends to be
between 0.1-1.0 µm, whereas the NRL tends to have larger particle sizes around 0.3-2.0 µm (14, 44,
45).
2.4.1 Manufacturing Process

Porcelain formers (moulds) are used to form the gloves following the simplified flow chart shown in
Figure 2.4. The formers must be clean and free from contamination, as small imperfections, dust,
glove residues can cause defects in the product formed (46). A clean former is dipped into a
coagulant. The coagulant acts to destabilise the compounded NRL/NBR material and adhere the
material to the former, creating the glove film. Thus, the amount of coagulant present on the former
controls the thickness of the glove material. The longer the former is held in the coagulant (dwell
time), the thicker the glove will be. Most commonly, the coagulant is calcium nitrate, but other
coagulants can be used (14). The coagulant covered former is then dried in an oven before being
dipped into the compounded glove material. The deposited material will take on the shape of the
former, developing the glove, as shown in Figure 2.5. This is then leached by placing the former in
hot water to remove residual surfactant from the wet NBR film. Where NRL gloves are used, this
leaching process has also shown to remove some of the proteins which cause allergies. The leached
product then undergoes vulcanisation in an oven in order to achieve the final physical properties and
dry out the material (14, 19, 38).
11
Figure 2.4. Glove manufacturing process
Figure 2.5. Glove formed on porcelain mould.
2.4.2 Post-dip processing

The final product will need treatment to reduce the surface tackiness of the material. This tackiness
reportedly makes the gloves harder to don and allows gloves to stick to each other in the packaging,
causing issues when trying to remove from the boxes (47). It is important to note, that whilst on the
former, the glove surface exposed to the atmosphere becomes in the inner surface of the glove. This
form of manufacturing process is known as ‘on-line’ and requires no human intervention to carry out
any part of the process (48). Until 2000, powder (such as starch) was used to coat the donning surface.
12
However, due to the rise in the incidents of latex allergies, there have been concerns over the proteins
in NRL being made airborne upon the removal of the glove after the powder has interacted with the
latex proteins (34, 49). Consequently, in 2010 the Health and Safety Executive (in the UK) released
guidelines stating that NRL gloves must be free of powder, prompting the NHS to stop purchasing
powdered NRL gloves (50).
Chlorination
Since the halt on using powders on gloves came into effect, chlorination has become the most utilised
method of treating gloves.
There are three ways to induce glove chlorination, which are as follows:
• Chlorine gas can be dissolved into water and gloves subsequently held into the water
• Exposure of gloves to an aqueous solution of organic chlorine
• Acidification of an aqueous solution of sodium hypochlorite with hydrochloric acid, and
sodium thiosulphate neutralisation, which the gloves are then dipped into (51, 52)
For this research, the acidification process was used. Chlorine (Cl) is released via hydrolysis of the
Sodium hypochlorite (NaClO) with water (H2O) to release hypochlorous acid (HClO) (53):
NaClO + H2O  Na++ HClO + OH
The hypochlorous acid then further dissociates to form chlorine (Cl2):
HClO + H3O++ Cl─  Cl2 + 2H2O
In the on-line chlorination procedure, the gloves are still on the former, and are exposed to a chlorine
solution, usually in a rotating drum (14, 47). This is then neutralised with water and then dried to form
the final product. Other methods of chlorination exist, including allowing the chlorination of both the
inside and outside of the gloves (depending on the chlorine strength). However, the on-line method
is most common (16, 38, 51). In the chlorination process, the polyisoprene double bonds in the latex
polymer are susceptible to the addition of chlorine (14, 54). This allows chlorine onto the surface,
acting as an accelerated ageing, which removes the surface tack and stiffens the material. As this is an
age accelerating process, the chlorination stage needs to be tightly controlled, as this severely affects
the shelf-life of the finished product. Where NRL has been used, over-chlorination can be identified
by the discolouration on the glove (16, 55). Double-dip chlorination can also be used, whereby the
gloves are chlorinated twice to further reduce the surface tack. Gloves that are not chlorinated twice
have better grip properties for the user, but stick to each other in the box, causing issues regarding
dispensing (14, 38).
13
Surface coating
As an extra step to the chlorination process, the glove films can also be treated by a chemical coating.
Coating with polymers, such as hydrogel, a hydrophilic acrylic polymer which absorbs moisture, gives
the glove surfaces a smoother finish (56, 57). This is said to improve the donnability of the glove
material. There are two methods whereby polymer coatings would work. Coating with a hydrogel will
allow the absorption of water (hydrophilic), causing the inner surface to be slippery, allowing a
smoother frictional interaction between the skin and the polymer. If coated with a hydrophobic
coating, then the water will be repelled, separating the skin from the polymer and reducing contact
(16). This allows the moisture to effectively act as a lubricant. Yip and Cacoli (14) hypothesise that
these surface treatments are good for donning, as they provide a topography which consists of hard
spherical particles, which are fixed into the soft polymer matrix. This allows a smooth interaction for
the skin, as it rolls over in a ‘ball-bearing’ fashion, reducing surface contact area. The application of
these coatings is not well discussed in the literature, due to them being patented technologies.
Coatings can be applied on-line before the final drying stage. Priming the wet gel before dipping into
the coating can aid the adhesion of the coating. The gloves that are removed from the formers at the
end of the process can also be treated by washing the gloves in the desired treatment polymer. This
method results in coating both the inside and the outside of the glove, which may affect properties
such as grip, as discussed with chlorination. Other polymers such as polyurethane can also be used,
and new polymers are being developed such as the anti-microbial chlorhexidine-gluconate coating
(58).
2.5 Glove Standards

After manufacturing, the gloves are tested to check if they comply with appropriate standards. Gloves
must conform to either the American Society for Testing and Materials (ASTM) or European Norm (EN)
standards, which contain slightly different requirements of the films, as shown in Table 2.1. In order
to be used in the United Kingdom, gloves must conform to the EN455 standard (59, 60). This standard
covers the testing of the gloves for integrity, strength, shelf life and carries the CE mark. Gloves must
also comply with EN 374, which describe the properties required by gloves to protect from chemicals
and micro-organisms (61, 62). To test the gloves, every batch formed will have a percentage removed
and tested for pinhole leaks, chemical permeation, visual defects and tested for their mechanical
properties. Mechanical properties include testing for the force at break, tensile strength, and the
elongation. The key differences between the EN and ASTM standards are the width of the material
sample cut for testing, and the tolerances of these tests (38). These tested gloves must fall into an
Acceptable Quality Level (AQL), which for the EN is 1.5%, which meets the requirements of the Medical
14
Device Directive. The AQL level is calculated as a percentage of the batch of gloves that contains any
defects and this must not be exceeded (60).
Table 2.1. Standards for medical examination glove testing (38) showing force at break (Fb),
elongation (Eb) and tensile strength (Ts).
Before Aging After Aging
Sample Thickness
Standard
width (mm) (mm)
Fb Eb Ts Fb Eb Ts
(N) (%) (MPa) (N) (%) (MPa)
EN 3 ≥6.0 ≥6.0
ASTM 6 ≥0.05 ≥500 ≥14.0 ≥400 ≥14
2.6 Medical glove assessments

Although a lot of testing is present to ensure the glove is acting as an integral barrier to the hands,
there is little testing in industry with regards to how these gloves interact with the user, and in turn,
their end performance. It can be argued that the glove assessments and standards should also be
focusing more on the user compatibility, rather than just the protection properties of the gloves. Very
few areas of literature aim to seek out how medical gloves can be assessed to fully evaluate the extent
at which placing a barrier between the fingers and the patient or tools in a medical setting can, for
instance, affect tactile and haptic feedback.
2.6.1 Tactile Sensitivity

Tactile sensitivity is defined as the ability to extract information from a foreign object to determine
the texture, shape, size and possibly orientation via manual exploration (63). To facilitate the tactile
sensitivity through the glove, thinner gauges have been created. However, questions concerning the
rupture rate and durability of these thinner gloves are being raised (64, 65). The most common
method of assessing tactile sensitivity is the use of the monofilament tests (Figure 2.6) (12). In this
test, the subject is blinded, and a microfilament is pressed onto a part of the hand. Once the filament
buckles, the examiner ceases pressure application, and the participant confirms if contact has been
felt. The filaments vary in diameter and are identified by manufacturer assigned values ranging from
1.65-6.65 (66). The limit of detection is the smallest diameter that can be sensed by the participant. A
15
major limitation of this test is that the thicker filaments buckle at higher loads. Thus, the pressure at
the filament contact will differ between the varying degrees of thickness, as more force is required to
make the thicker material buckle. Also, as the filament buckles, the contact area of the thinner
filaments are likely to increase, as the nylon bends and presses against the skin, which may lead to a
false positive identification.
Figure 2.6. Monofilament test showing a range (2.83, 5.07 and 6.10 gauge) of nylon thread
thicknesses.
The literature regarding these tests is conflicting. In the monofilament tests, Park, Davare, Falla, et al.
(63), Novak, Megan, Patterson, et al. (67), Tiefenthaler, Gimpl, Wechselberger, et al. (68), Bucknor,
Karhikesalingam, Markar, et al. (69), Mylon, Lewis, Carré et al. (70) Che and Ge (71) and Thompson
and Lambert (72) state that tactility is reduced whilst using gloves when compared to the bare hand.
However, Shih, Vasarhelyi, Dubrowski, et al. (73), Nelson and Mital (74) and Johnson, Smith, Duncan
et al. (75), show that no change in sensitivity is present when donning medical gloves. When
comparing glove materials, Kopka, Crawford, and Broome (41) found that there was no difference in
sensitivity between NRL and ‘NRL-free’ gloves. It must be noted, that between these studies, many
variations are present in the methodology. Some studies use higher thicknesses of monofilaments to
assess sensitivity and different glove materials are used throughout.
Another common method of assessing tactile sensitivity is the use of the two-point
discrimination test (Figure 2.7). In this test, two prongs are placed on the skin at varying spacing of 1
-25 mm, with the aim of identifying at what distance the two prongs feel like one (76). The prongs are
attached to a disk (10 cm diameter) which allows for easy changing between different sizes. Fry, Harris,
Kohnke, et al. (77) showed that gloves do not hinder the identification of two distinct points. However,
other studies investigating this found that gloves can reduce the discrimination of two points (67–69,
72, 73, 78, 79). Again, this test has limitations, given that there is no limit on how much pressure is put
onto the surface by the subject and the glove material can spread out the pressure across the finger.
16
It has also been noted by Lundborg and Rosén (80) that it can be tempting for examiners to apply
enough pressure to evoke a result, introducing bias into these tests and producing inaccurate results.
Whilst Fry et al. (77) stated that they did not find any differences in 2-point discrimination tactility
between gloves and no gloves, they looked at ulnar and radial surface testing. The radial nerve is less
likely to serve purpose in clinical situations, as the back of the thumb or hand is less likely to be used
(81), which draws questions on the effect gloves have on tactility.
Figure 2.7. Two-point discrimination touch test. Point spacing numbers correspond to mm of the two
distinct points.
Other commonly occurring tests in the literature involve the use of roughness discrimination. These
tests require participants to identify varying bump sizes or roughness/patterns (63, 70, 82–86). Of
these, only two studies found that detection rates declined when gloves were worn (63, 86).
Sandpaper (and different paper grits) has also been used as a means of measuring discrimination.
Mylon, Buckley-Johnstone, Lewis, et al. (87) showed that subjects could perceive roughness
differences when moving their gloved fingers across sandpaper, but not when statically pressing.
Palpation or surface anomaly detection with patients would require interaction with skin and tissue
that is much more viscoelastic and pliable than the materials used in these studies. Thus, it would be
imprudent to say that gloves have no effect on the ability to discriminate surface anomalies on or
within the body by these test methods. More advanced assessment methods have been produced,
such as the Simulated Medical Examination Tactile Tests (SMETT) developed by Mylon, Lewis, Carré,
et al. (88). In the ‘bumps’ SMETT test, 100-600µm pimples were 3D printed on a soft rubber-like sheet
which was fixed onto a board. Participants were asked to run their fingers across the sheet to see if
any pimples were identifiable. The ‘Princess and the Pea’ SMETT test required participants to identify
pegs of varying heights (2.5-14.5mm) which were submerged in silicone. This was based on the Hans
Christian Anderson tale, titled by the same name, whereby the royalty of a woman is identified by her
ability to feel a pea placed under her mattress (89). A similar test was carried out by Gnaneswaran,
17
Mudunuri, and Bishu (86) which utilized 1.25cm dried glue spots covered by sponge. Although the
SMETT tests in Mylon et al. (88) do appear to be a valid means of in-situ glove assessment, several
areas with room for improvement exist in the methodology and design. It was found that the silicone
became stiffer over time, making it harder to identify the pegs. Participants also varied placing their
fingers flat or perpendicular to the test beds, which could produce different results due to the
dispersion of mechanoreceptors. This could provide differing results between people and between
the gloving conditions. Although the bumps and roughness discrimination tests are a good measure
of identifying tactility loss, it could be argued that the use of more appropriate surfaces that replicate
the body and environmental conditions would lead to more accurate results in a clinical context.
An inability to detect a pulse is the most common reported reason for removing or not
donning gloves. A study by Mylon, Lewis, Carré, et al. (8) considered the effects of gloves on pulse
detection using a design whereby water was pumped through one of five tubes under a layer of
neoprene sponge using a peristaltic pump. They found significant differences in ability to feel the
‘pulse’ in gloved and ungloved conditions. The authors note that this cannot accurately simulate a
pulse test due to the pump limitations on the speed and pressure. Also, there was the potential for
bias due to the inability to vary the pulse location. Using a pump that will allow the same pressure and
speed of blood would be more simulative of in-situ glove use. A more quantifiable way of assessing
tactility differences is by using vibrations. Carré, Tan, Mylon, et al. (90) used a vibrating platform to
measure the sensitivity difference of fingers when a NRL glove was donned. The glove was found to
reduce tactility when compared to the no-gloves condition. However, only one participant was used
for this. Overall, studies regarding tactile sensation show that gloves have an adverse effect on ability
to feel. However, the extent to which this becomes a detriment remains unknown. Many of these
tests aim to quantify tactility loss, but results differ between studies, possibly due to the different
methodology used. To quantify tactility loss, further studies looking at how the gloves dampen
vibration, like in Carré et al. (90), could prove vital for future work. Some of the studies discussed here
were conducted prior to the banning of powder coated NRL, thus the results may not be applicable to
gloves used today due to the differences in manufacturing. Gnaneswaran et al. (86) stated that
powdered NRL gloves are better because they have ideal properties, such conforming to the hands
better. There is a chance that this powder could affect the frictional properties of gloves in any of
dynamic tactility tests, which may give different results. Many of the studies cited regarding sensitivity
are vague in terminology, describing the gloves tested as ‘thick’ or ‘thin’ without giving any
measurements. Due to the issues arising with these assessments, it is unknown as to how much
medical gloves affect the tactile sensitivity of a user, but it is clear they are having a negative effect.
18
When comparing glove thickness, studies have found that the thinner gloves provide more sensitivity
(41, 78). Surgical gloves are often marketed as offering better ‘tactile sensitivity’. However, studies
looking at the difference between medical examination and surgical gloves have found no measurable
difference in sensitivity (68). Table 2.2 shows a breakdown of the available literature regarding tactile
tests where the use of gloves has been compared to the bare hand condition.
19
Table 2.2. Studies relating to the effect gloves have on tactile sensitivity. Reduced sensitivity is defined as a reduction in ability to discriminate or identify
sensations.
No of
Study Materials Test Results
Participants
Brunick, Burns, Gross, et al.
29 NRL and Vinyl Roughness discrimination No significant difference observed
(84)
Nelson and Mital (74) 20 NRL Roughness discrimination, needlestick No significant difference observed
Similar results between bare finger and

Klatzy and Lederman (85) 12 NRL Roughness discrimination
gloved finger
Mylon et al. (87) 30 NRL and NBR Roughness discrimination Reduced roughness perception
Phillips, Birch, and Ribbans Two-point discrimination Roughness

20 NRL No significant difference observed
(79) discrimination
Two-point discrimination
Thompson and Lambert (72) 20 and 30 NRL Monofilament Tactile sensitivity reduced with gloves
Vein location
Han, Kim, Moon, et al. (78)

40 NRL Two-point discrimination Tactile sensitivity reduced with glove
Fry et al. (77) 53 Not Stated Two-point discrimination No significant difference observed
20
Two-point discrimination and
Shih et al. (73) 10 NRL No significant difference observed
monofilament

Tiefenthaler et al. (68) 20 NRL Tactile sensitivity reduced with gloves
monofilament

Bucknor et al. (69) 52 Not Stated* Tactile sensitivity reduced with gloves
monofilament
No significant difference observed

Johnson et al. (75) 42 NRL and NBR Monofilament
between gloves
Mylon et al. (70)

18 NRL and Vinyl Monofilament Tactile sensitivity reduced with gloves
Park et al. (63) 12 NRL Bump discrimination Tactile sensitivity reduced with gloves
Mylon et al. (8) 19 NRL and NBR Pulse location simulation Tactile sensitivity reduced with gloves
Simulated Medical Examination Tactile

Mylon et al. (88) 39 and 34 NRL and NBR Tactile sensitivity reduced with glove
Tests (SMETT)
Carré et al. (90) 1 NRL Vibration sensitivity Sensitivity reduced with glove
*Presumed to be NRL as the methodology states the participants were asked about NRL allergies.
21
2.6.2 Dexterity
Dexterity is defined as the ability to carry out tasks using motor skill, moving the hands, fingers and
arms. The conformity of bending of the hands and fingers, material folding, and thickness are the
main areas were gloves affect dexterity (9). Together these can impact the ability of users to carry
out tasks and manipulate objects with fine skill. Numerous dexterity tests have been developed
comparing medical glove material performance. Widely used in these studies, are pegboard tests,
such as the Purdue Pegboard (Figure 2.8) and the Crawford Small Parts Dexterity Test (CSPDT)
(Figure 2.9). Tiffin and Asher (91) produced the Purdue Pegboard test, which is designed to assess
gross dexterity by measuring how many pegs can be placed into the board in a set time using both
hands and each hand separately. Washers can also be placed on the pegs in the test to allow further,
finer assessments. The CSPDT test requires the placement of the pins with the use of tweezers,
assessing finer dexterity. The results generally show that dexterity is only significantly affected when
thicker or double gloves are worn (31, 37, 40–42, 52, 59–65). Although little difference is observed
between gloves, vinyl showed more of a decrease in dexterity when compared to barehanded,
whilst NRL shows a minimal decrease. Drabek, Boucek, Buffington, et al. (97) demonstrated that
vinyl gloves do not affect performance when using a grooved pegboard test (similar to the Purdue
Pegboard), regardless of the size of the glove used. However, the study did find that the time taken
to remove the pegs from the board was significantly increased when best-fit gloves were worn.
Moore, Solipuram, Riley, et al. (92), Pourmoghami (94) and Drabek, Boucek, Buffington, et al. (99),
however, found that dexterity was decreased in the Purdue pegboard test with NRL when the wrong
sized glove was worn. Francis, Hanna, Cresswell, et al. (100) and Hamstra and Dubrowksi (101)
demonstrated the varied skill of professionals is a factor in these assessments. They found students
had impaired dexterity and dropped more pins than experienced surgeons in the pegboard tests.
This would suggest that in order to accurately interpret results of pegboard tests, recruited
participants should all be at the same level of experience. This is an important factor that should be
considered in all tests of this manner.
22
Figure 2.8. Purdue pegboard (46 × 30 cm).
Figure 2.9. Crawford small parts dexterity test (24 × 23 cm).
Gauvin et al. (102) states that these dexterity tests are of a good enough sensitivity to measure
performance and discriminate between gloves. However, numerous issues exist when using these
tests to assess the effects of gloves. The primary issue is that the frictional properties of each
person’s hand are different. Thus, in the ‘no gloves’ variable, results could be different due to the
variation of skin friction, sweat and oils present naturally on the fingers as well as contaminants
(such as food residue). No mention of washing the pegs or hands is present in any of the literature,
which would standardise this test and reduce contamination. Many of these studies include the NHS
first choice gloves: NBR and NRL as well as gloves that are not commonly used such as butyl and
vinyl (20). Nelson and Mital (74) and Gnaneswaran et al. (86) investigated the effect of NRL thickness
23
on dexterity by having subjects cut paper along lines using scissors and found that a glove thickness
of 0.83 mm did not have an adverse effect on dexterity during the task. Studies oriented at more
specific clinical tasks, look at the effect of gloves on suturing and syringing (8, 86). These studies also
did not observe any significant effect on dexterity between glove materials. The tasks and protocols
in most of these studies are very similar throughout and reveal very little to no impact on dexterity
when any of the gloves are donned. This would suggest that either the gloves are not having any
effect on dexterity or that the tests are not of a good enough sensitivity to pick up the differences.
However, dexterity is reported to be affected when thicker gloves are donned. More novel tests
need to be designed to simulate the tasks encountered when gloves are worn. Work has already
been carried out in this area (syringing and suturing (8, 86)), but more studies are needed to create a
test that produces repeatable, reliable results, and provide enough discrimination to highlight
differences between the effects of dexterity with different gloves. Table 2.3 shows a breakdown of
available tests within the literature investigating how medical gloves affect dexterity against the bare
hand.
24
Table 2.3: Studies relating to the effect gloves have on the dexterity. Reduced dexterity defined as a reduction in time taken to carry out tasks/quality of
task.
No of
Study Materials Test Results
Participants
Nelson and Mital (74) 20 NRL Paper Cutting No effect on dexterity
Mylon et al. (8) 19 NRL and NBR Suturing No effect on dexterity
No effect on dexterity, although

Moore et al. (92) 27 NRL Purdue Pegboard dexterity reduced if smaller or
larger gloves used
Sawyer and Bennet (95) 24 NRL and NBR Purdue Pegboard NBR gloves reduced dexterity

Drabek et al. (99)
20 NRL Purdue Pegboard dexterity reduced if smaller or
larger gloves used
Fry et al. (77) 53 Not Stated Purdue Pegboard No effect on dexterity
Park et al. (63)

12 NRL Purdue Pegboard Gloves reduced dexterity
Allahyari, Kahnehshenas,
30 NRL and NBR Purdue Pegboard No effect on dexterity
and Khalkhali (98)
25
Pourmoghani (94) 10 NRL Purdue Pegboard and O’Connor dexterity reduced if smaller or
larger gloves used
Berger, Krul, and Daanen

(96) 30 NBR Purdue Pegboard and O’Connor Gloves reduced dexterity
Johnson et al. (75) Manual dexterity reduced when

42 NRL and NBR Purdue Pegboard and CSPDT
thicker gloves worn
Gloves reduced dexterity in the

Pegboard test but not with the
Mylon et al. (70)
18 NRL and Vinyl Purdue Pegboard and CSPDT CSPDT. Fine dexterity was
reduced with the screwing
action in CSPDT
No effect on dexterity
regardless of glove size used.
Drabek et al. (97)
20 Vinyl Grooved Pegboard Test Time to remove pegs was
significantly quicker with best
fit gloves.
26
2.6.3 Grip and friction
The frictional properties of medical gloves is an important factor which glove manufacturers should
consider. It is these properties which allow for the users to ascertain grip and have a sense of force
they are applying, which is imperative for the ability to carry out tasks such as holding tools and
applying pressure to wounds. Friction is defined by the resistance to motion of objects, which move
over each other. Therefore, grip relies on the properties of the materials in contact. At a
fundamental level, the friction is determined by the contact of minute surface anomalies, known as
asperities. These asperities can interlock on surfaces and increase friction or sit atop each other and
reduce friction (103, 104). Two types of friction are commonly measured (105). Static friction is the
amount of friction present between two stationary objects. When one object moves, in this case the
hand or glove, the static friction is measured at the start of the sliding process. The sliding friction is
known as the dynamic friction. Static friction tends to be greater than that of the dynamic, due to
the increase in friction forces as the surface roughness’ (asperities) locally weld (106). The addition
of moisture can have a great impact on the friction, by separating the surfaces and reducing the
friction (71, 107). This could be a problem with bare skin due to the presence of sweat glands and
introduction of contaminants such as oils from pores (103, 108). c
Accurate force control for grip precision demands finer detailed information from
mechanoreceptors in the skin. Thus, when these are blocked by a membrane, it would be reasonable
to assume that grip force would be impaired (63, 73). Much of the work regarding grip is oriented at
industrial applications and extra vehicular activity gloves for use in space (9) , with few looking at
medical gloves. Gnaneswaran et al. (86) showed that when powder was present on the gloves, more
grip force was exerted. This is presumably because the frictional properties of the gloves were
lowered due to the presence of the powder. However, similar findings were reported in Shih et al.
(73), Willms, wells and Carnahan (109), and Kinoshita (110), who reported that thicker NRL gloves
made participants exert more grip force when picking up a desired load. They conclude that gloves
should be thicker in order to retain a greater grip force. However, it has been shown that that
thicker gloves impair sensitivity (41, 78). Park et al. (63) looked at the role of mechanoreceptors in
force control and the effect of gloves on precision grip. The study found that there was a 20%
increase in measured grip force when subjects lifted a heavy object after lifting a light object when
gloves were not worn. This grip force was not significantly different when the same test was carried
out with NRL gloves, suggesting the sensorimotor effects of gripping were not affected by the gloves.
Only one study was located where there was a measured decrease in the grip force with NBR and
vinyl gloves (111). Many of these studies appear to see an increase in force as beneficial, as grip is
imperative for control. Although, these studies do not look at the effects of this force increase on the
27
hands. It could be that this increase in grip, however slight, could affect fatigue on the hand and arm,
thus affecting dexterity and performance. It should also be noted, that the over-gripping effect could
be due to a reduced friction coefficient between the object and the hands when gloves are
introduced. As with Willms et al. (109), assessing how much pressure is instinctively applied, and
then how that adjusts overtime during a surgical procedure is required. However, assessing whether
the change in load is down to the gloves or the tasks carried out during surgery itself could prove to
be a difficult.
Many of the published studies looking at the frictional properties of medical gloves focus on
surfaces that are impractical to the medical profession, such as glass and sandpaper (73, 112, 113).
Mylon et al. (87) found no significant difference between NRL and bare hand friction with sandpaper
but found a significantly lower friction coefficient with NBR. Carré et al. (90) studied the friction of
surgical gloves on steel and found that the friction coefficients of NRL gloves were greater than the
bare hand condition. This finding is different from Shih et al. (73), who noted that the coefficient of
friction decreases when NRL gloves are donned. Laroche, Barr, Dong, et al. (114) looked at the static
friction of wet NRL and NBR gloves on a variety of dental tool patterns. Greater friction coefficients
for tools with knurled surface patterns were observed. Although this is the first test to incorporate
real tool patterns with fluids, this could be greatly improved by having more realistic bodily fluids in
contact with the gloves, such as blood and saliva (115). The study also did not include a control, such
as no gloves or dry gloves to compare. A paper published by Anwer (116) includes the use of blood
to assess friction modification in NRL gloves. They found that blood, and blood and water (1:1
mixture) increased friction coefficients when the compared to the dry state with NRL gloves. The
friction tests were carried out on a surgical scalpel. Although a unique study, which is required in this
area, a few issues are noted. The author states that friction increases as the blood starts to
coagulate under mechanical stress. However, bloods from different sources and treatments have
different rheological properties, including different viscosities and different shear rates, which will
influence the frictional behaviour (117, 118). Furthermore, the temperature of the blood, which is
not mentioned in the study, will induce a difference in coagulation properties, thus affecting the
friction. However, this is the only study to date considering the effects that blood could have on the
friction of medical gloves. In addition, the study found that double gloving induced a greater friction
coefficient than a single layer. However, no explanation is offered as to why this may be. It is
possible the frictional changes are due to the relative motion of the latex-latex interaction sliding
within the gloves, causing a difference in friction. No statistics were performed to conclude that this
difference is significant. Nevertheless, this study shows that consideration needs to be paid to the
reason why gloves are worn, that is, for their protective barriers, and contaminants should be
28
incorporated into future tests. This is a fundamental consideration, especially in surgical tasks where
gloves are more likely to be in contact with bodily fluids, and then a wide range of tools. Including
fluids into assessments would provide a greater significance to the results of any of the friction and
grip studies being conducted.
The frictional properties of the inside of the gloves also requires consideration from glove
manufacturers. Often a quick change of gloves is needed in fast-paced environments which can be
made difficult with the presence of moisture (15, 119, 120). Roberts and Brackley (57) found that
coating the glove with hydrogel gives a lower coefficient of friction than chlorination treatment, thus
enabling easier donning. Pavlovich, Cox, Thacker, et al. (120) demonstrated that when hands were
wet, the gloves became more difficult to don and greater force was required to pull the glove on,
when compared to dry. However, in this study, the hands were wet, with no drying process involved.
This is unrealistic of the real-world scenario of requiring a quick change of gloves. Damp skin has
been demonstrated to have higher friction coefficients when compared to dry skin (121). As many
issues lie with donning gloves with damp hands, this should be of consideration when assessing the
frictional properties of the inner surface of glove materials (120).
Medical Glove Surface Interaction
In the studies where friction and grip are concerned, there is a disregard for surfaces which
examination gloves encounter when in use. Medical gloves encounter a wide array of substances
and surfaces in a clinical setting in particular. Therefore, these studies should be accounting for the
materials that are contacted, allowing for a more targeted approach as to how gloves affect friction
and grip. In order to do this, it must be understood what surfaces gloves most commonly come into
contact with. All UK general practitioners (GP) are encouraged to provide minor surgical procedures
to the populations they see. This generally reduces the pressure in the hospitals around the UK.
These minor surgeries are all outlined in the Standard General Medical Services Contract (2009)
(122). The minor surgeries contracted to be carried out in a GP office can be placed into one of two
categories:
• Injections and aspirations: Drugs/vaccines injected into the body via a hypodermic needle
and syringe. For example, the injection of cortisone into the foot to elevate plantar fasciitis
pain.
• Excisions and incisions: removal of a small or large area of tissue. For example, the removal
of a sebaceous cyst (excision) or the draining of an abscess (incision) (NHS, 2017).
29
The list of medical equipment used in these procedures is exhaustive, as is the list of general medical
equipment nurses and doctors will interact with in hospitals and GP surgeries. Equipment most likely
to be used is shown in Table 2.4. These have been chosen based on likelihood of contact in common
minor procedures and general nursing healthcare, along with bodily fluids that are likely to be
encountered.
30
Table 2.4. Tools and equipment used in minor procedures to give an overview of the surfaces and textures encountered.
Bodily fluid(s) in
Equipment Use/handling Material(s) Surface finish/textures contact (between glove
surface and equipment)
Disposable scalpels are

composed of polystyrene
Used to cut into tissues/samples for Smooth top and All major bodily fluids
handles with stainless steel
removal of foreign objects or bottom. Sides where could be in contact with
blade. Metal scalpels, more
implantation of devices. Pressure is the thumb and middle the scalpel after the
Disposable scalpel often used for surgical
applied to scalpels, as these are required finger are placed have initial breaking of the
applications are more
to break the skin, but are equally deep ridges present skin. Blood, mucus,
commonly composed of
extremely sharp (123, 124) (125) saliva, etc.
stainless steel handles (124,
125)
Blood/saliva in some
Grooved/ridged dental procedures.
Thumb Used for suturing where required and patterns dependent Possible blood exposure
Stainless steel (127)
tweezers/forceps removal of foreign materials (126) upon the manufacturer if used to hold back skin
(128) and/or extraction of
foreign objects.
Minimal risk of
Used for the injections of fluids into the
contamination. There is
body as well as the aspiration of blood Ridges on thumb press
Polypropylene plastic syringes a risk of alcohol being in
Syringe (with and other fluids such as pus. The force and where syringe is
with a stainless steel needle contact from alcohol
needles and cap) applied to syringes is dependent upon the stabilised by index and
(129) wipes used to clean the
task and fluid being injected. The act is middle finger(128)
site of puncture when
normally carried out slowly (124).
taking fluids.
31
Dependent upon the
site with which these
Used for the handling and cutting of
are being used.
Scissors/handled tissues and medical aids such as bandages Smooth on the handles
Steel (124, 130) Frequently used to
forceps and tape (128, 130). where grasped (131)
cut/make stitches, so it
can be presumed blood
would be in contact.
Blood in most clinical
cases, could be other
Textured – knurled
fluids present
Used for the scraping and debriding of (diamond shape, for
Curette Steel (114) depending on area of
tissues (131). example) or annular
surgery (mucus and
(circular grooves) (114)
saliva). Presence of
saliva in dentistry.
These tubes have many applications.
Some are used to aid breathing in
Tubing – probes, intubation or as a flow path for bodily May be in contact with
Poly vinyl chloride (PVC),
catheterisation, fluids out of the body or drugs into the blood and or/excretive
polyethylene, silicone (132) Smooth (131, 132)
suction, dialysis, body, such as blood cleaning in dialysis. bodily fluids such as
and oxygen tubing. These tubes are usually attached at their urine and faeces.
end, one normally to the patient/a device
in/on the patient and an instrument (132)
32
The list in Table 2.4 is not exhaustive as many other surfaces are contacted, and many more
contaminants would be present. The surfaces of some of these equipment are manufactured to be
smooth, whereas others are manufactured to contain spaced grooves to allow enhanced grip (e.g. a
scalpel). Whilst the friction studies conducted show a difference in the friction of gloves, the surfaces
they use are not representative of the surfaces which are normally encountered with medical
examination gloves.
2.6.4 Double gloving

Throughout the literature, it is recommended that where surgery is a high risk due to diseases, such
as HIV, two layers of gloves are worn to minimise exposure. Much of the research on double gloving
is centred around puncture indication during surgeries (i.e. using different coloured gloves to indicate
the outer glove layer has ruptured) (133). Johnson et al. (75) and Kopka et al. (41) both show that
dexterity decreases when thicker gloves are worn. Thus, it would seem reasonable to believe that
dexterity would be more affected when multiple layers are worn, as the thickness is increasing which
could restrict movement. However, Webb and Pentlow (134) found that double gloving did not affect
dexterity when assessing knot tying. Fry et al. (77) also determined that there was no statistically
significant difference in performance when subjects wore two glove layers compared to one when
completing the Purdue Pegboard test. There are, however, opposing results with regards to the
effect of double gloving on tactile sensitivity. Novak et al. (67), Shih et al. (73) and Han et al. (78)
show that there is a loss in tactile sensitivity when assessed by monofilament or two-point
discrimination. On the other hand, Fry et al. (77) and Webb and Pentlow (134) show no statistical
difference in two-point discrimination between one and two glove layers. Germaine, Hanson, and de
gara (135) demonstrated that double gloving is not favoured amongst surgeons. Out of the 170
medical staff asked, when practice recommends that they double glove, 78 said that they do not as it
decreases their dexterity and 62 said that it was not comfortable. Regardless of the evidence
involving the practicality of double gloving during high-risk surgery, there is little discussion in the
literature as to how to double glove. Hollaus, Lax, Janakiev, et al. (136) discuss using the same sized
gloves as well as whichever size makes the user comfortable. However, much of the literature
focuses on the method used in Fry et al. (77) and recommend double gloving by using a larger inner
layer glove and a smaller outer layer glove. The authors suggest this reduces dermatological issues
but does not offer any insight into how dexterity and tactile feedback may be affected via this
method.
33
2.6.5 Donning
The donning of medical gloves is a relatively unexplored area in the literature. As previously stated,
much of the research conducted in glove friction applies to the outer interaction with the
environment, such as glass (113). Glove donning is a complex process due to the stretching and
bending of the materials as they are being pulled. The hand is inserted to the glove and the other
hand is pulling the material/holding it in place. If the glove gets stuck, it is common practice to stop
and manipulate the glove to aid the process of the glove going onto the hand. However, this task is
made increasingly difficult upon the addition of moisture (15, 57, 119, 120). Previous studies looking
at glove material donning have used loads as an assessment of donning ‘ease’. Cötë, Fisher, Kheir, et
al. (119), Pavlovich et al. (120), and Edlich, Heather, Thacker, et al. (15) have looked at the loads used
in donning medical gloves. By attaching the cuff of the glove to a ring, in which there are load
sensors, they found they could measure the force applied to don the gloves. The studies collectively
found load ranges between 29-78 N were being used to don the gloves when the hand was in a wet
condition. In all studies, the wet condition required a lot of water present on the surface of the
hands, making the studies unrealistic to a donning scenario. Glove donning with ‘wet’ hands tends to
arise as a function of improper drying or sweat generation, rather than hands having water dripping
from them. The loads used in these studies are extremely high, so much so, that in Pavlovich et al.
(120), the gloves tore under the applied loads and no measurements were recorded in over half of
the gloves used. Furthermore, the studies do not consider the realistic donning process, in which the
glove is not in a fixed cuff position held in one location. Much of the time, the gloves are being
stretched in different places. It is unclear in the studies if the subjects were able to use their other
hand to pull the material in places where the glove did not fit. If not, then more force would be
applied to make the hand slide down the glove when the material is stuck to the hands. These
studies appear to be more about comparing how much force is needed with different internal glove
coatings, rather than looking at how ‘easy’ it is to don the gloves. It is reasonable to assume that that
less force used to don the gloves would make the glove easier to don. However, these studies lack
application to the processes used in the donning of gloves. Furthermore, very few studies have been
produced linking the internal coatings used on medical gloves to the donning process.
There are many companies stating the benefits of different coatings and how chlorination
helps the donning process by smoothening the surface, but little literature is available on this. Much
of the work conducted in this area is protected under patent, thus it is unknown whether there are
significant rigorous tests being conducted which could be related to realistic working conditions
gloves are used in. Roberts and Brackley (137) looked at the friction of medical gloves on the inner
34
surface with skin at a load 4N and a glass surface at 0.32N. Roberts and Brackley (57) also compared
the friction of hydrogel gloves in a similar study, using a load of 0.4N with fingers. However, no
reasoning is given for the selection of these loads. The authors find that generally, the hydrogel
coated gloves are preferred, and the friction coefficients tend to be lower than the chlorinated
gloves. It should be noted that all these studies are investigating the natural rubber latex gloves with
different applied coatings. No other gloves appear to have been used. It is important to include other
materials in these types of studies, as the market trend shift due to the increasing demand for non-
latex gloves, these literatures will allow for up-to-date assessments of the available gloves.
2.6.6 Durability
Under EN 455 guidelines, gloves are tested for their durability and puncture resistance. The puncture
resistance/durability is inferred from the force required to break the materials, as discussed in the
glove standards (see Section 2.4). In industry, durability on gloves can be tested via the use of
abrasion resistance, using soft pads which are placed onto the material, and relative movement
wears the gloves over time (138). As the primary function of gloves is to act as a barrier, and protect
the hands, several studies exist looking at the barrier integrity of the gloves. Since the introduction of
non-latex gloves, much of the research has focused on comparing glove materials. Many tests look at
abrading gloves with abrasive materials such as grit (139), which do not represent the realistic
working conditions these gloves are used in, when in a medical setting. It is appreciated that gloves
are not used solely for medical purposes. However, this study compares the grit durability method
with a simulated clinical study. The simulated clinical work is a good indicator as it shows the
durability of gloves when in-situ. However, this is impractical to the manufacturing industry (139,
140). Further tests investigating the failure rate of gloves whilst in surgeries have been conducted
(136, 141, 142). Many of these tests are looking at NRL gloves. Much of the earlier research focuses
on PVC gloves, showing that the NRL material has lower failure rates (35, 139, 143, 144). Further
research looking at NBR gloves found that NRL and NBR had similar failure rates (64, 145). Studies
which focus on the failure rates of gloves in surgery draw comparisons to other studies to indicate
that gloves are either more durable, or less durable. However, there are a variety of surgeries used
between studies (136, 146, 147) ranging from oral surgery, to osteology, where bones are broken
and many more tools are used. There is also a tendency to statistically compare the perforation
rates. However, in some studies there are orders of magnitude difference between the duration
procedure as well as the total number of procedures included, thus making for an unfair comparison
between studies, leading to erroneous conclusions. Studies have shown that gloves tend to wear out
between the thumb and the index finger, as this section of the glove undertakes a greater amount of
mechanical strain. These also highlighted the potential failure for examinations gloves are at the
35
joints of the knuckles (138, 148). However, little regard is paid to the nature of these gloves in most
of these studies. Those looking at novel durability methods compare gloves with other studies,
although no thicknesses are published in some of the work (139). It could be that the differences in
results between some of the gloves are due to the thickness, rather than the material itself, as
previously highlighted (12).
2.7 Size and fit

Glove fitting is a vital part of both the donning process and the practicality of wearing gloves. Gloves
should freely fit the contours of the hands, and act like a second skin layer. If too large, the glove will
be easier to don, but the excess loose material can cause issues with dexterity and sensitivity. If too
small, the gloves can be difficult to don and restrict movement of the fingers (99). No studies could
be found which investigate glove sizes, specifically regarding how they are sized and how that relates
to the general population. The government provides protective glove size recommendations for
Europe and the United States only, but no information is given as to how these sizes are ascertained.
To determine the best fit of a glove, two measurements are required, which are shown in Table 2.5
(149), as provided by the HSE. Firstly, the hand should be measured from the base of the palm to the
tip of the middle finger. This produces the ‘finger length’. Secondly, the ‘palm circumference’ is
measured just below the knuckles. These two measurements provide a glove size for the hand. This
protocol appears to be universally adopted. However, no reference is provided as to where this
protocol is obtained.
Table 2.5. Finger and palm measurement sizes for selecting the best sized glove (149).
Finger length (cm) Palm circumference (cm) Size

16.0 15.2-17.8 XS
17.1 17.8-20.3 S
18.2 20.3-22.9 M
19.2 22.9-25.4 L
20.4 25.4-27.9 XL
21.5+ 27.9+ XXL
2.8 Paper grading

To identify gaps where research is required with regards to glove performance assessment, a paper
grading system has been adapted from Harmon and Lewis (150) and Watson, Christoforou, Herrera,
et al. (151), who found that study design and reporting of key findings was flawed across the field of
36
tribology. The aim of this grading differs from these by the way of trying to identify areas where
research should be focused in the future. The grading is focused on application of research to
relevant systems within the clinical environment and categories differ from those used in previous
papers in order to reflect the aim and the practices used in this area of research. It is noted that this
way of grading papers is subjective, thus the grading has been kept to matter-of-fact as opposed to
subjective analysis (i.e. focusing on participant number and statistical analysis as opposed to the
experimental design). It is important to note that not all of these criteria will be applicable to the
study designs for this grading. This means that a study which scores highly is not essentially a good
study, but a study that fulfils more of the criteria. Similarly, a high score may include all criteria, but
whether the entire study is fundamentally flawed will not be determined by this grading. The
research papers used in this review have been graded according to the following criteria:
(1) Repetition of work: does the study repeat tests to obtain an average result?
(2) Number of participants/samples: does the study have a respectable number of

participants/tests? (The average participant/sample number throughout the glove
assessment studies is 30, thus this has been used as a benchmark. Anything <30 does
not meet these criteria).
(3) Statistical analysis: has a statistical analysis been conducted?
(4) Conclusions: are the conclusions in the paper based on the results presented?
(5) Representative simulation: does the work simulate a clinical and/or surgical scenario?
E.g. suturing, pulse-feel, etc.
6) Glove material: have multiple glove materials been studied?
A grade ‘A’ constitutes as fulfilling 5–6 of the criteria; grade ‘B’ constitutes fulfilling 3–4 of the criteria
and grade ‘C’ constitutes 0–2 of the criteria. A graphical representation of the results is displayed in
Figure 2.10. Much of the research is focused on durability; this is most likely to be because the
durability of medical gloves is significant to function. Thus, this is an area of primary focus. However,
these assessments have focused mainly on obtaining and testing gloves after surgical procedures
have been performed. As there are a great number of different surgical procedures, each with
different tasks and different periods of glove wearing, this may result in incomparable data within
the literature. Very few studies focus on the grip and frictional properties of medical gloves. It is
recommended that further research should be carried out into the frictional properties as well as the
performance effects of tactile sensitivity and dexterity of gloves. Although many of the studies here
have good grades by these defined criteria, many of the methodologies lack standardisation and do
37
not have a control or a baseline reading of the gloves (8, 35, 71–75, 77, 78, 80, 83, 84, 41, 85–88, 90,
92–96, 42, 97–101, 109–113, 57, 114, 116, 138–144, 146, 63, 147, 148, 152–159, 67, 160, 68–70).
Figure 2.10. Grading of glove related papers to assess gaps in knowledge.
2.9 Conclusions
Overall, the literature suggests that sensitivity, friction, and grip are affected when medical gloves
are worn, but dexterity is not. The differences in results between studies of the same tests may be a
result of the difference in glove properties, arising from differences in manufacturing. Many studies
do not discuss this possibility, and numerous studies looking at dexterity do not assess thickness of
the gloves. Linking the key manufacturing parameters to performance will give better information
about which processes affect performance. When assessing medical gloves, the purpose of the
barriers should be considered in the tests. Thus, contaminants should be incorporated where
possible. Understanding how these contaminants affect the frictional properties of the gloves will
provide insight into how medical gloves perform. Including the assessment of a desired performance
characteristic into the manufacturing process will ensure the production of high-quality gloves that
are fit for purpose.
38
Chapter Three: Questionnaire
In the first instance, it is important to establish the issues surrounding medical glove use. Exploring
user perceptions is key to unlocking the areas where problems may occur. In the literature review in
Chapter 2, it was shown that there are flaws in previous work, as the studies conducted lack the
realistic conditions gloves are used in. Therefore, it is important to establish what gloves are in
contact with, which may contaminate them, and affect their performance. The areas where
performance is then affected can then be explored in more detail in order to further assess the
effects examination gloves have on users.
3.1 Introduction
Very little has been published on the perception of how examination gloves affect the user. This
leaves very little understanding about how gloves affect the users. Mylon, Lewis, Carré, et al. (7)
used a focus group of thirty four NHS medical staff to ascertain areas where perceived problems lie
with surgical gloves. It is important to note that this study focused on surgical gloves, which are
different from examination gloves in that they are designed to be worn for longer periods of time,
and have more precise sizing (161). Examination gloves, however, are to be worn for shorter time
periods and range in sizes (extra small, small, medium, large and extra-large) (149). Many studies
show gloves have an effect on the performance of the user when carrying out tasks (6, 12).
Furthermore, gloves have been shown to cause issues with contact dermatitis and the skin drying out
when gloves are worn for longer periods of time, or if any allergies are present (34, 162, 163).
In most cases, gloves are used to protect the user from contaminants (such as blood), but
there is little literature assessing how these contaminants affect performance (114, 116).
Furthermore, there is no literature suggesting what contaminants gloves commonly come into
contact with. To determine how these contaminants are affecting the performance, it is important to
establish the nature of these contaminants which are coming into contact with the gloves.
Examination gloves are used extensively throughout various sectors. Arguably, the most important of
these sectors is the area of medical care. Although, many other sectors rely on the performance of
examination gloves for health and safety. For example, forensic scientists rely on examination gloves
to protect evidence from contamination (164) as well as protecting themselves from contaminants,
such as blood. These gloves need to provide the same level of dexterity and sensitivity that any
medical care professional would require, in order to fully evaluate physical evidence.
39
3.2 Aim and scope
It is thought that, as few studies can be found regarding glove perception, further questions should
be asked in order to uncover further issues surrounding gloves. As observed in the literature review
in Chapter 2, there is a huge gap in studies relating to the performance of examination gloves once
exposed to contamination. In order to assess this, it was pertinent to obtain information regarding
what contaminants are contacted amongst glove users, what the perceptions of the gloves are and
what issues they are facing with the two most common glove materials. Thus, the aim of this study is
to gather views on the perception of examination gloves amongst common users. The purpose of this
study is not to obtain differences on the glove preferences, but rather to obtain information on what
glove materials are being worn routinely, the perception of the gloves being used, the ease of
donning and doffing the gloves, the contaminants they come into contact with, and how the users
perceive the way that contamination affects the performance when carrying out tasks.
3.3 Methodology
3.3.1 Questionnaire
Due to the regulations and restrictions surrounding research into medical devices within the NHS, it
was decided that data would be gathered via questionnaires. Although limitations exist with
questionnaires, in terms of user response and bias from the questions (i.e. leading questions), they
are effective ways to reach a wider range of participants quickly and efficiently, without the
requirement of obtaining participants for focus groups. The use of focus groups was discussed;
however, it was decided that as the aim was to reach a wider audience a questionnaire would be
more efficient. Attaining a wider audience would give a more accurate and varied view of the kinds
of issues that arise from glove use. The research received ethical approval from the Department of
Mechanical Engineering (No: 022731).
Participants were approached by e-mail, as well as verbal communication, aimed at professions

which require frequent glove use (e.g. private medical centres, dentists, testing laboratories, police
forces, forensic laboratories etc.) based in the United Kingdom. In addition to this, the questionnaire
was also posted on nursing/medical/laboratory forums in the United Kingdom (.co.uk domain).
Participants were invited from various job roles to take part in the survey. The only requirement for
participation was that either NBR and/or NRL examination gloves had to be routinely worn in order
to conduct their daily tasks. Only NBR and NRL were asked about this study due to trends in the
market leaning towards a shift from NRL material to NBR (38). As discussed in Chapter 2, other glove
materials are used (PVC and chloroprene), but these are less frequently encountered. The
40
participants were asked to fill out a questionnaire consisting of eight questions, based on the
perceived issues with gloves obtained from the literature review in Chapter 2 (dexterity, sensitivity,
durability etc.). The questions were also asked to further explore the issues brought up by the focus
group in Mylon et al. (7), and then questions were asked to see whether these issues were present
when gloves were contaminated. Some of these questions asked were presented with set multiple
choice answers, using the answers which were similar to those obtained from the focus group in
Mylon et al. (7). This was to entice more participants by making the form easier and quicker to
complete. Participants were asked the following questions:
1. What is your job title?

2. Which glove material(s) do you routinely wear?
o Latex
o Nitrile
o Other (please specify)
3. Regarding LATEX medical gloves, if you have worn this material currently/previously, which
of the following do you think are ISSUES with the gloves (please state other issues where
applicable).
o Fit
o Comfort
o Dexterity (ability to carry out tasks)
o Sensitivity
o Grip
o Ability to put on
o Ability to remove
o Tearing
o No issues
4. Regarding NITRILE medical gloves, if you have worn this material currently/previously, which
of the following do you think are ISSUES with the gloves (please state other issues where
applicable).
o Fit
o Comfort
o Sensitivity
o Grip
o Ability to put on
o Ability to remove
o Tearing
o No issues
41
5. What are the most common contaminants that these gloves encounter in your job role?
o Blood
o Urine
o Saliva
o Mucus
o Other bodily secretions (please state the nature)
o Liquid drugs (please state nature of drug)
o Powders (please state nature of powder)
o Other (please state)
6. When LATEX gloves are contaminated with these substances, what issues does this cause?
o Comfort
o Sensitivity
o Grip
o Ability to remove
o Tearing
o No issues
7. When NITRILE gloves are contaminated with these substances, what issues does this cause?
o Comfort
o Sensitivity
o Grip
o Ability to remove
o Tearing
o No issues
8. Do you feel there are any issues with carrying out specific tasks because of the medical
gloves you normally wear? E.g. it is more difficult to open a box with gloves on.
To limit response bias (tendency to give false answers), the questionnaire was completely
anonymised, with no names or any personal data being gathered in conjunction with the answers
provided.
3.4 Results
In order to show the frequency of responses the results are displayed either as a percentage or the
total number of user responses. A total of 172 useful responses were obtained over a period of five
months. This number did not include seven responses where the respondents did not answer any of
the questions.
42
3.4.1 Respondent roles
The different roles of the questionnaire responders have been categorised into job sectors and
displayed in Figure 3.1. Over half of the respondents worked in a clinical role as a nurse or doctor
(n=100). Other respondents came from the health-related fields of dentistry (n=14), veterinary
(n=11), care (n=12) or were medical students (n=5). Collectively, these roles make up a total of 82%
of the respondents. The remaining 18% of respondents had either a forensic, medical, or non-stated
field laboratory technician role (n=30).
Lab Technician
18%
Medical/Nurse
students
3%
Veterinary
6%
Clinical
Care Assistant 58%
7%
Dental
8%
Figure 3.1. Respondents of questionnaire by job sector (n=172).
3.4.2 Glove materials

Participants were asked which examination gloves they routinely wear in their day-to-day work. A
total of 102 of the respondents said that they used the NBR gloves, whereas 66 respondents stated
they used NRL. Three respondents stated they use vinyl routinely, two of which were in the clinical
field (nursing) and one a care assistant. These results are displayed in Figure 3.2. Only one person
stated they used chloroprene gloves. None of the respondents indicated they did not know what
material they routinely used, and all respondents indicated they routinely wear only one type of
glove. Some of the users of NRL, however, did state they used NBR where NRL allergies are present in
patients (n=12).
43
Chloroprene Vinyl
1% 2%
Latex Nitrile
38% 59%
Figure 3.2. Gloves routinely worn by respondents (n=172).
3.4.3 Contaminants contacted

Figure 3.3 shows the responses for what contaminants are frequently encountered. Many of the
respondents reported exposure to multiple contaminants. The contaminants encountered has been
broken down by job sector and shown in Section 3.4.4. Overall, blood is indicated to be the most
contacted contaminant (n=149) followed by: urine (n=95); medical disinfectants (n=81); saliva (n=68);
liquid drugs (n=54); water (n=52); sweat (n=50); faeces (n=46); powders (n=44); mucus (n=40);
pus/discharge (5); vomit (n=1); dirt(n=1) and food (n=1). Where powders or liquids were indicated,
respondents were prompted to state what type of substance was touched (i.e. oily liquid or fine
powder). The results of this are shown in Figure 3.4. These responses come mainly from lab
technician roles, where finer powders are contacted. Some respondents also indicated they have
regular contact with granular powders, but the nature of these powders was not disclosed. In terms
of liquid drugs, it appears there are three categories these drugs fall into which are solvent, watery,
or oily.
44
160
140
120
Number of responses
100
80
60
40
20
Contaminant
Figure 3.3. Contaminants coming into contact with medical gloves used throughout the various fields.
35
30
25
Number of responses
20
15
10
0
Fine powders Granular Oily liquids Watery liquids Solvent liquids
powder
Contaminants
Figure 3.4. Liquid drugs and powders contaminating gloves as indicated by respondents.
Contaminants by sector
Contaminants have been broken down into the job sectors to show the variation of contaminants by
role and shown in Figures 3.5. The most varied of the contaminants is shown in the clinical sector
45
(Figure 3.5a) where the gloves are exposed to all of the contaminants shown in Figure 3.3. Also, as
indicated by the compilation of responses in Figure 3.3, blood exposure is prevalent throughout all
job sectors. All (100%) of workers in the clinical sector stated they had regular exposure to blood,
along with dental (Figure 3.5b) and veterinary care (Figure 3.5d). Saliva is also common throughout
the varied job sectors. Many respondents from the lab technician role stated they were
contaminated with fine powders from illicit drugs (n=30). On the other hand, respondents from the
clinical field stated they had drug residues from tablets (i.e. paracetamol) contaminating the gloves.
Some respondents also indicated they had contact with granular powders. However, they did not
state what the nature of these powders were (n=4). Lab technician and clinical respondents also
indicated contact with oily liquids such as steroids (e.g. testosterone) (n=32) and watery liquids (n=6),
as well as solvents (n=6). The responses for each role are to be expected, e.g. more bodily fluids in
the clinical, than in the laboratory roles. The result that stands out more, is the sweat in the dental
sector (7%, Figure 3.5b). It is unclear how sweat would be exposed to medical examination gloves in
a dental setting, as the oral cavity is the area where most activity would take place. However, there
could be issues with stabilising patients’ heads, which could contaminate gloves with sweat.
a) Clinical b) Dental Care

100 100
90 90
80 80
70 70
60
% Response
60
% Response
50 50
40 40
30 30
20 20
10 10
0 0
Medical Disinfectant
Urine
Feaces
Saliva
Pus/Discharge
Blood
Water
Vomit
Fine powders
Oily liquids
Solvent liquids
Snot/Mucus
Watery liquids
Sweat
Dirt on skin
Saliva
Fine powders
Oily liquids
Blood
Water
Watery liquids
Snot/Mucus
Sweat
Contaminant Contaminants
46
e)
% Response % Response
c)
100
0
10
20
30
40
50
60
70
80
90
0
10
20
30
40
50
60
70
80
90
100
Blood Blood
Urine
Urine
Feaces
Feaces
Saliva
Saliva
Sweat
Contaminant
Care Assistants
Sweat
Contaminant
Nursing/Medical Students
Medical Disinfectant Water
Snot/Mucus Snot/Mucus
Food
f)
% Response
0
10
20
30
40
50
60
70
80
90
100
% Response
d)
0
10
20
30
40
50
60
70
80
90
100
Blood
Urine
Blood
Feaces
Urine
Saliva
Feaces
Sweat
Saliva
Powders
Water
Contaminant
Veterinary Care
Snot/Mucus
Contaminant
Laboratory Technicians
Figures 3.5 (a-f). Breakdown of all contaminants contacted by job sector.

Fine powders Water
Granular powders Fine powders

Oily liquids Oily liquids
Solvent liquids Watery liquids
47
3.4.4 Perceived issues with NRL and NBR gloves
Four of the 172 respondents stated they had never worn NRL or had NRL allergies. Also, nine of the
respondents stated they had no issues; thus, the NRL results are displayed as issues amongst the 159
respondents. In the NBR gloves, 10 respondents stated they had no issues and 2 stated they have not
worn NBR gloves before. This brings the total number of respondents for the issues with NBR to 160.
The results of both NRL and NBR are shown in Figure 3.6. In total there were 429 responses to the
issues regarding the NRL gloves and 597 for the NBR gloves. The issues perceived encompass both
material issues (e.g. stiffness) and the performance (e.g. dexterity). The major issue reported with
both gloves is the loss of tactile sensitivity (NRL n=77, NBR n=94). Table 3.1 shows the results and the
between the number of responses with each issue. The greatest differences are noted in the
thickness, ‘elasticity’, and dexterity between the two glove types. Due to the comments surrounding
the elasticity (e.g. more stretchy/stronger), it is likely that the respondents were referring to the
stiffness of the material.
Latex Nitrile
Do not wear/never worn
None
Sweatier
Tearing
Ability to remove
Ability to put on
Perceived Issue
Grip
Thickness
Loss of Sensitivity
Dexterity
Elasticity
Comfort
Fit
0 20 40 60 80 100
Number of responses
Figure 3.6. Results obtained from questionnaire regarding issues perceived with NBR and NRL gloves.
48
Table 3.1. Differences in response volume for issues between NBR and NRL gloves.
No of
responses Difference
Issue NBR NRL
Fit 64 44 20
Comfort 44 63 19
Elasticity 69 34 35
Dexterity 74 44 30
Sensitivity loss 94 77 17
Thickness 90 39 51
Grip 68 45 23
Ability to put on 50 48 2
Ability to remove 11 10 1
Tearing 33 25 8
Sweatier 6 0 6
No Issues 10 9 1
Do not wear/never worn 2 4 2
Total responses 597 429 168
3.4.5 Perceived issues with contaminated gloves

Figure 3.7 shows the responses regarding medical glove use once they have been contaminated with
the powders/fluids stated in Figure 3.4. The results are shown in Table 3.2, which shows that fit,
dexterity, and sensitivity loss have the greatest differences between the two glove types. In the NRL,
a total of 402 issues were reported, compared to 527 issues for NBR. When NRL and NBR gloves are
contaminated, most issues arise with regards to grip (NRL n=101, NBR n=119); tactility loss (NRL
n=82, NBR n=105) and dexterity (NRL n=73, NBR n=107). A total of forty respondents for the NRL, and
fifty-six respondents for the NBR, stated there were issues with the ‘elasticity’ after contamination.
More issues are reported in the NBR than the NRL, except in the issue of tearing (NRL n=23, NBR
n=17). Overall, it is shown that more issues exist for the NBR gloves.
49
Latex Nitrile
Do not wear/never worn
None
Perceived Issue with contaminated gloves
Tearing
Ability to remove
Grip
Loss of Sensitivity
Dexterity
Elasticity
Comfort
Fit
0 20 40 60 80 100 120
No of responses
Figure 3.7. Results obtained from questionnaire regarding issues perceived with NBR and NRL gloves
once contaminated.
Table 3.2. Response volume for issues between NBR and NRL gloves once contaminated with
substances indicated in Figure 3.4.
No. of responses
Contaminated Contaminated Difference
Issue
NBR NRL
Fit 38 10 28
Comfort 48 49 1
Elasticity 56 40 16
Dexterity 107 73 34
Loss of Sensitivity 105 82 23
Grip 119 101 18
Ability to remove 37 24 13
Tearing 17 23 6
No issues 7 7 0
Do not
2 4 2
wear/never worn
Total 527 402 125
50
3.4.6 Further issues
When prompted to discuss further issues where gloves may affect specific tasks, 49 respondents did
not answer or responded with no further issues. Many of the remaining comments expanded on the
issues previously mentioned. For example, some respondents stated that the gloves were ‘too
slippery’ and saying NBR was thicker, and more uncomfortable rather than reporting on a specific
area they feel is affected. Although the question asked was to name specific tasks, there were only
eight specific tasks identified. The remaining issues fall into problems such as: slipping of fingers
inside the gloves, changing gloves, sweat generation, and size/fit of the gloves. All of the results are
displayed in a sunburst diagram in Figure 3.8. An attempt has been made to identify and split up
specific gloves where they have been stated. However the majority of comments did not state a
particular glove material.
Figure 3.8. Diagram showing range of comments regarding specific issues with gloves. ‘Not stated’
indicates no specific material was given in the response.
51
Major issues identified are around the size/fit of gloves (n=25) as well as the changing of gloves
(n=24). Where fit was mentioned, many respondents also commented on the slipping of their fingers
inside of the glove. This was reported to cause issues in forensic laboratory respondents, as the
materials cause them to incorrectly identify bumps and striations on materials. Also, in a clinical
setting, there were comments focused on slipping affecting respondents’ ability to carry out port
connections where gloves are worn. There were 24 respondents who expanded on the donning
incapability, stating it was extremely difficult to don gloves once any moisture was present on the
hand, hindering their ability to carry out further tasks due to ill-fitting gloves. These issues are
highlighted in Figure 3.9. Other comments included the colour of NRL was not nice once it was
exposed to sweat in the hand (latex staining, n=2) and gloves made the hands sweatier (n=9). Which
is a common issue noted in NRL gloves, whereby the chlorination treatment of the gloves causes
them to yellow, even more so on exposure to sweat (14). When specific material issues were
mentioned, most of these focused on NBR tearing (n=10), causing gloves to be changed which is time
consuming. Along with this, comments appeared around NRL being ‘too elastic’ (less stiff) in nature,
and snags easily (n=7). This reportedly leads to issues with glove tearing, snapping back onto the skin
and sometimes misidentification of evidence in forensic laboratory tasks.
Not Stated Both materials Latex Nitrile

30
25
20
No of Responses
15
10
0
Changing gloves Sweat generation Finger slipping inside Size/Fit
Issue
Figure 3.9. Breakdown of the responses surrounding issues from the comment section of the
questionnaire. ‘Not stated’ indicates that no specific glove was given in the response.
52
Comments regarding specific tasks have been split into two sections; dexterity and sensitivity and are
displayed in Figure 3.10. The only sensitivity issues mentioned were with regards to pulse
identification (n=28) and physical examination by using percussion to feel organs (n=2). Issues with
dextrous tasks included equipment slipping from contamination (n=4); tearing/sticking of gloves in
cap lids (n=5); applying dressings (n=2); undoing small knots for evidence preservation (n=3); fine
control, such as applying pressure with a scalpel (n=3) and others reported ‘issues with dexterity in
most tasks’ (n=8). Although more issues were identified regarding dexterity, more respondents
reported specific issues with sensitivity, all of which were respondents working in the clinical sector
(n=30).
Palpitation/pulse feel Physical exams Fine control

Undoing knots Applying dressings Removing caps/lids
General dexterity Equipment slipping
35
30
25
Number of responses
20
15
10
0
Sensitivity Issues Dexterity
Figure 3.10. Breakdown of the responses regarding specific tasks affecting participants of the
questionnaire. Tasks have been split into two sections to show the two main issues affected.
3.5 Discussion
The questionnaire shows that, although it is clear that NRL is still being used, the NBR gloves are
more routinely worn. This is what is reported and predicted in line with the market trends (38). Three
respondents stated that they used PVC gloves. All of which were in the medical field, dealing directly
with patient healthcare. However, it is recommended by the National Health Service that vinyl gloves
are not be worn where contact with bodily fluids is apparent due to their high failure rates (165).
Thus, it is unclear whether these respondents are aware of which glove material they are using. The
contaminants with which the gloves are in contact are mostly pertaining to bodily fluids, due the
53
majority of the respondents working in the medical field (83%). These fluids are the fluids that would
be expected to be in contact with gloves, the most common being blood, urine, and saliva. However,
not previously considered, medical disinfectants also appeared as common contaminants.
Regulations include that clinical staff maintain good environmental hygiene, thus cleaning around the
patients/hospital/equipment is a vital part of their practice (22, 165). Furthermore, there are needs
to come into contact with cleaning/disinfectants, when it comes to phlebotomy (inserting a needle to
remove blood) (166, 167). These cleaners are normally alcohol-based wipes; thus gloves can be
contaminated before proper use (168, 169).
NBR and NRL gloves are perceived to have similar issues; however, it is shown that NBR has
more issues than the NRL glove. This could be due to the fact that only 39% of the respondents use
NRL routinely, whereas 59% routinely use NBR. The largest issue for both gloves is around the
sensitivity and ability to put on. Issues which were both highlighted in Mylon et al. (7), with the
sensitivity issues being prevalent with 23% of the participants. In this study, only one issue was raised
in the NBR that did not appear in the NRL, which was that the glove induced more sweat. The term
‘sweatier’ was used with the participants, thus it is thought that this means more sweat is generated
when NBR is worn, in comparison to the NRL glove. Ability to put gloves on is a notably frequent
issue with both gloves, which is an area which has seldom been explored in the literature (6, 9, 12).
The only issue where NRL is more frequent than NBR is in the area of comfort. This could be due to a
skin reaction to the NRL or from the material parameters (i.e. tighter on the skin). Mylon et al. (7)
found contradictory issues, whereby more contact dermatitis was reported by the participants (5.9%)
using the NBR gloves.
When the gloves are contaminated, the number of issues reported decreased by 6% for NRL
and 12% for NBR. This is likely to be because the question was concerned about issues which were
exacerbated by the presence of contaminants (i.e. not the issues that were already perceived to be
present). Unsurprisingly, grip is the highest reported issue with both gloves, and dexterity/sensitivity
is also reported to be affected. Comments were made on ‘elasticity’ being an issue after
contamination, which could be due to the way these contaminants are reacting with the gloves, to
either affect the stiffness of the material or elicit such a feeling. In addition, the ability to remove is
noted as a more frequent issue when compared to the general issues with gloves asked previously.
This is likely to be because it is harder to grab the glove due to the reported perception in reduced
grip capability. It is unclear why fit would be an issue once gloves are contaminated. It is possible that
the glove reaction to certain substances makes the user feel less comfortable, which respondents are
perceiving as issues with fit (such as solvents making the glove feel tighter as they evaporate). It
54
should be noted that ‘fit’ was not on the multiple-choice section for this and was typed in the ‘other
issues’ section.
3.6 Questionnaire limitations

As with any questionnaire, there are several limitations with the results obtained from this study.
Recollection bias is the most prominent issue in surveys. It is possible that some participants will not
know which glove materials they are wearing but will have attempted to answer under the
assumption of using a particular glove (i.e. participants could be using NBR but believe it is NRL).
Also, if one particular glove has been worn for a long period of time, participants could, perhaps,
think of issues that they believe may be associated with the other glove materials rather than
reporting experienced issues. This has been highlighted in Mylon et al. (7) where participants
reported the ‘thicker feeling’ gloves affected their tactility; however, the gloves were not measurably
thicker. This may arise as a function of bias due to glove preference through use. As market trends
lean towards other glove materials (such as the synthetic NBR over the NRL) there is a shift from
hospitals purchasing habits, and more synthetic gloves are favoured from a business point of view
(i.e. less incidences of allergies) (38, 165). However, as discussed in the Mylon et al. study (7) this
leads to a bias in ‘favoured’ gloves. In essence, the people who wore NRL gloves for longer before the
switch to NBR, show a preference for the NRL material. A way that this could have been mitigated
was by asking if the gloves being used currently in their job role was their preferred glove choice, or
part of an institutional decision of which gloves are being used. However, this study was pertaining to
what gloves are used and the issues are perceived with these gloves, not about how users compare.
Although it would be interesting to fully assess how glove users, who have had to change from their
preferred glove materials, evaluate different gloves.
Although the contamination questions asked about any further issues, when providing
answers, it is possible that participants filled out answers with the mind-set that the issues had not
gone away, rather than them being further issues. For example, a respondent could have reported
comfort as an issue for a NBR glove. Then when asked for further issues once the NBR glove had
been contaminated, the participant responds with ‘comfort’ as the issue has not gone away, inducing
a false positive for comfort being an issue when the glove is contaminated. Due to the nature of the
questionnaire, multiple choice answers were provided with encouragement to include issues which
were not stated in the answers provided. This box was utilised to add a wide range of substances for
the section regarding which contaminants the gloves came into contact with. However, this was
seldom used for the list of issues. Some of the participants used this box to comment on an issue that
was already in the multiple-choice section or to put an issue which was already present (i.e. writing
55
‘glove ripping’ instead of clicking on ‘tearing’). This could cause the issues, whereby recollection bias
makes the respondent think issues are present where none exist, just because they have seen the
word in front of them (170, 171). Furthermore, common issues with the gloves could be undetected
as participants do not have to think too deeply into their answers on an anonymised multiple-choice
questionnaire. Another limitation is how the participants link the perceived issues together is also
unobtainable from this study. This could be vital for perception of how glove users perform. For
example, the largest issue in NBR is the loss of sensitivity (n=94) and the second largest issue is
thickness (n=90). There is no indication in this questionnaire that the respondents believe that these
two could be linked.
3.7 Conclusions
The findings from this chapter are:
• The most common examination gloves being used are composed of the NBR material, which
participants appear to have more issues with than gloves composed of NRL. Although, this
could be due to the NBR gloves being more widely used, hence more issues are noticed. It
was shown, however, the more frequent issues being reported are similar for both of the
materials.
• The most frequently reported issues are the loss of sensitivity, dexterity, grip, and ability to
don. These issues, with the exception of donning ability, are reported to become further
issues when both of these glove materials become contaminated.
• Comfort is also reported as a larger issue in NRL when compared to NBR, which could be
down to the tightness of the gloves creating more sweat (although sweat was a reported
issue in NBR and not NRL), being tighter or underlying allergies/sensitivity.
• Fit is more of a perceived issue with the NBR gloves, but an inherent issue throughout both
glove types.
Overall, this questionnaire reveals the contaminants gloves come into contact with most frequently,
as well as highlighting what effect glove materials may have on user performance. This allows for a
greater depth of study into how glove behaviour is influenced by contamination. The issues
surrounding donning and doffing the gloves are of great interest. Although the issues surrounding
glove donning are relatively unexplored in the literature, there appears to be a problem amongst the
general population of glove users.
56
Chapter Four: Donning and doffing
As previously discussed in Chapter 2, there is a lack of studies linking glove properties to donning
capability and ease (6). To date, there is little literature regarding how the donning process is
affected when moisture is introduced via either sweat or hand washing (172, 173). This was further
identified as an issue from the questionnaire analysis in Chapter 3. It is referenced in the literature,
and a selling point of many gloves, that the internal coatings e.g. polymer coatings (such as acrylics or
hydrogels), or surface treatments help aid the donning of gloves (16, 57, 137, 174). The studies
investigating the differences between coatings show that friction is reduced when hydrogels are used
compared to chlorination (16, 57, 137, 174). However, beyond the fact that the friction is decreased,
there is no evidence that this makes a glove ‘easier’ to don. In addition to this, there is an issue raised
regarding the fit of gloves, and many people reported in the questionnaire (Chapter 3) that they
were ‘between sizes’ and found gloves either too small or too large (172). Thus, assessing whether
commercial gloves correlate to the hand sizes is required for assessing donning performance, as
larger gloves are easier to don, but ill-fitting, which may affect performance (172, 173). This chapter
concentrates on the inner glove interaction, that is, the donning side of the glove and the skin with
different glove materials and treatments. The efficiency of donning and doffing gloves with different
treatments, and with moisture present, is explored to mimic the conditions in which gloves are
donned.
4.1 Introduction
Performing basic hand washing between glove use decreases the risks of infection between patients
as the gloves could become damaged, contain pinholes, or break during use, leading to the hand
being contaminated (175). However, the use of hand hygiene is considered unnecessary by some,
and it has been shown that washing prior to and after glove use does not reduce pathogen
transmissions (176). Nevertheless, it is still recommended that hands should be washed every time
gloves are worn, especially given the covid19 pandemic where the use of PPE has increased and
encouraged to be used where they would not have prior to the outbreak (31, 177, 178). A quick
change of gloves is salient in high pressure environments, such as the medical field. The issues with
donning gloves with wet hands are documented, as the glove sticks to the skin more and creates
issues when trying to don gloves (7, 15, 119, 120, 179–181). Previous studies exploring force-donning
relationships have shown that that wet hands require more force to don medical gloves (15, 119,
120, 179, 180). However, in the ‘wet hands’ condition, no drying took place, which is not
representative of the conditions gloves are donned in The increase in force and sticking increases the
57
time taken to put gloves on and/or leads to ill-fitting gloves with loose material in areas, and is
regarded as unpleasant (181). Thus, assessing how the internal coatings and treatment of
examination gloves could enable manufacturers investigate different coating requirements, and help
purchasers/users make more informed choices regarding the selling point of gloves. Roberts and
Brackley have previously assessed the coating applied to NRL surgical gloves, studying friction with
skin and glass (57, 137). The work suggests longer chlorination time induces less friction, and
hydrogel performs better due to an overall decrease in friction when compared to the chlorination.
The wet condition was attained by applying water to the glove, rather than the finger. This could
alter friction in two ways which are not replicable of the realistic donning scenario. Firstly, the
coatings applied could affect the contact angle and the wetting of the surface, causing the moisture
to spread. Secondly, the water-finger interaction should be present prior to hand insertion into the
glove. Moisture in the hands has been shown to change morphology, which may induce changes in
contact area (182). Furthermore, only one participant was used, and skin has been proven to have
great variation between people, different interactions with moisture and thus, more people would
have induced a greater variation in results. It is possible that the conclusions based on these results
are erroneous and no statistical analysis was performed on any of the results. More recently
Manhart, Hausberger, Maroh, et al. (174) looked at the tribological aspects of gloves with skin and
compared porcine skin in an attempt to correlate human friction to an animal model. The study
found that the skin had a good match with correlations between porcine and human skin friction.
However, the human testing was only conducted once, whereas the porcine was tested 10 times.
Although, similar conclusions were drawn to other friction studies, leading to the inference that
gloves with polymer coatings are easier to don because there is less friction present (57, 137). No
gloves, to date, compare the findings of internal glove coatings and their effects on the donning
process and link this directly to the frictional properties of medical examination gloves.
4.2 Aim and scope

The aim of this study was to investigate the effects of donning different glove materials with dry and
wet hand conditions, replicating in-situ donning scenarios. Wet skin has been shown to have higher
friction coefficients when compared to dry skin (121, 183). This difference in friction can highlight the
differences between glove treatments, coatings, materials, and the hand conditions, as well as
informing better glove selection. These differences were determined by defining a protocol in which
different gloves are assessed for how long they take to don and doff in dry and wet conditions. In
conjunction with this, the frictional interactions between the skin and different internal glove
58
coatings were assessed, with the aim of exploring correlations of medical glove friction to the time
taken to don the glove.
4.3. Materials and Methods

4.3.1 Glove materials and characterisation
Glove Selection
Four types of commercially available medical examination gloves were used in this study. Chlorinated
(cl) NRL (branded UltraCruz) and chlorinated NBR (branded Arco) were selected. These types of
gloves are the most commonly used in industry due to the ease of access in the market, and they are
relatively inexpensive (38). The intention of this study was to compare multiple glove coatings with
the chlorinated treatment; however, the nature of the coatings is not determinable, as they are
patented to the manufacturers and not disclosed on the packaging. Attempts were made to
determine the coating via contacting the manufacturers, however no response was received. Thus,
only one brand (Glove+) was used which had an internal polymer coating (PC) inside the NBR and NRL
gloves. This led to a total of four gloves being used (Figure 4.1). Obtaining the roughness of each
glove would be beneficial to the study, however due to the nature of the gloves, the surface
roughness could not be obtained. This is because the surface roughness measurement instrument
(Alicona) uses light to map the surface profile. In some cases, the material can reflect the light, which
causes issues with the image. The materials used in this study were either too thin, or too reflective
to obtain a detailed surface profile in which the average roughness could be determined.
Figure 4.1. Glove selection used in this study. From left to right; chlorinated NRL; polymer coated
NRL; chlorinated NBR; and polymer coated NBR.
59
Thickness and size measurement
Glove thickness (T) was measured using a Mitutoyo micrometer (quick-mini, ± 0.01mm). Twenty
samples of each glove type were measured at the location of the palm, middle finger, and fingertip.
Each measurement was repeated three times in each area per glove. The Health and Safety Executive
(HSE) recommends the measuring of hands across the palm, and the total length of the glove finger.
Therefore, in order to assess if the gloves were of similar sizes, the same measurements were
conducted on the gloves. Glove sizes were measured using a ruler in three areas, as shown in Figure
4.2. The areas measured were from:
• The distal middle finger to the knuckle

• The distal middle finger to the cuff
• The width across the palm
Where gloves were wrinkled/folded due to the packaging (as is visible in Figure 4.2), the glove was
flattened as best as possible and held in place to ensure no folds/wrinkles were visible. However,
some wrinkles may have contributed to differences in glove sizes. A total of 20 gloves were measured
from each batch to get an average size for all three measurements.
= Thickness
measurement
area
Finger base
Palm
Figure 4.2. Depiction of areas of glove used for measurements.
Tensile strength
Gloves were tested as per EN regulations, using a tester Tinius Olsen TL-190 tensometer (Figure 4.3a)
with a deflection rate of 500 (±2) mm/min. The EN 455-2 standards lay out the requirements of
testing for physical properties (60). Standards state gloves should be cut to yield a 3 mm wide strip to
60
be tested at 21°C (±2) with a humidity at 50% (±5) for physical properties. The glove was press cut
around the palm area to yield a 9 cm long section, which had a 3 (±0.05) mm wide testing section, as
in Figure 4.3b. The thickness along the 3mm wide strip was measured three times and averaged
using a micrometer (Mitutoyo, C11XBS). The cut glove section was marked at an initial 2.5 cm spacing
along the 3 mm strip. This was then loaded on the tensile tester and tested for the force at break
(Fb), elongation at break (Eb), and tensile strength (Ts). Testing was carried out in a temperature and
humidity-controlled room within the EN standards specification range, previously mentioned.
Acceptable Quality Levels (AQL) requires gloves be checked to ensure they meet these standards.
The standard practice is to test 2% of each batch of gloves, which should have no more than 1.5% of
glove fail (61). If above 2.5%, the gloves are seen as low quality and the batch, as a whole, fails. For
this study, as only a limited number of gloves were received, 12 repeats of these tests were
conducted. Two sections were press-cut from each glove (around the palm area), thus only 6 gloves
were tested (184).
(a) (b)
Laser
Sample
holder
Figure 4.3. a) Tinius Olsen TL-190 tensometer and b) Press-cut sample for EN standard testing
The modulus of the gloves was also measured at 100, 300 and 500% strain, as per EN standards to
produce stress-strain graphs for comparison of modulus. The stiffness (K) of the gloves was also
calculated for discussion on how stiffness of the gloves could affect the donning process. The stiffness of
each of the gloves was calculated using the stress at 100% strain using the following formula:
𝑠𝑡𝑟𝑒𝑠𝑠 (𝑎𝑡 100% 𝑆𝑡𝑟𝑎𝑖𝑛) × 𝑆𝑎𝑚𝑝𝑙𝑒 𝑊𝑖𝑑𝑡ℎ × T

𝑆𝑡𝑖𝑓𝑓𝑛𝑒𝑠𝑠 (𝐾) =
𝐼𝑛𝑖𝑡𝑎𝑙 𝑠𝑎𝑚𝑝𝑙𝑒 𝑙𝑒𝑛𝑔𝑡ℎ
Equation 4.1
61
where T is the glove thickness (185). The stress at 100% strain was used as it is thought that stretching the
glove beyond a 100% strain is unlikely. Stretching beyond this is an indication that the hand is not fitting into
the glove correctly, due to incorrect sizing. This was noted in the video analysis of donning (discussed in section
4.4.2), whereby it was visually apparent that the gloves were not strained to over 100%. This is, however,
unmeasured and a best estimate of the strain applied to the gloves when donning.
Contact angle goniometer
The wettability of a surface is measured through the contact angle (186). Contact angle measurements
were carried out using a goniometer (ramé-hart, model 100-06, Figure 4.4) with a static sessile drop
method. The gloves were placed onto the goniometer platform and 2 µl droplets of deionised (DI)
water was syringed onto the sample surface, from a height of 0.8 mm. The droplet was analysed
immediately after contact with the glove and was not left for a period of time.
Figure 4.4. Schematic of goniometer. The syringe deposits a measured drop onto the substrate on the
platform. This is then viewed via the viewing lens with sight aided by the light behind.
Strain
The gloves were tested for contact angles under strains of 0%, 25% and 50% to assess if strain affected
the contact angle of the fluids (assessing donned/un-donned scenarios). The strain of the gloves was
achieved using a stretching device, shown in Figure 4.5. This device is composed of two sections, a
static section affixed to moveable section, which allows stretching of an attached glove. The glove
sample was placed into the device and held with screws. All gloves were measured three times at each
strain.
62
Glove Movable
sample platform
clamped to which
device stretches
the clamped
glove
section
Figure 4.5. Stretching device with glove attached
4.3.2 Donning methodology
Three video cameras were set up in a triangulated position in order to capture all areas of the hand
as the glove was being donned and doffed. A schematic of this set-up is shown in Figure 4.6. Prior to
the study taking place, participants were asked to ensure their hands were washed and thoroughly
dried around 15 minutes prior to starting. No gloves were worn in this 15-minute period. This was to
get the hands into a natural state of moisture and temperature, ensuring all participants had a similar
environment for the ‘dry’ condition. Gloves were placed side by side on a stool in front of the
participants, who were then signalled verbally to proceed donning the gloves. Once participants had
donned the gloves, they were asked to hold their hands out palms down to signal they had
completed donning. They were then asked to doff the gloves and then hold out their hands once
again, to signal that they had finished the process. To measure the donning efficiency with wet
hands, participants were asked to wash their hands with liquid soap and warm water from the taps
within the laboratory, and then partially dry, by patting with paper towel, using only two sheets of
paper towel. Some remnants of moisture were still visible on the surface of the skin. The participants
were then asked to don and doff the gloves in the same manner as before. This was repeated for all
four types of gloves, in both wet and dry conditions in a forced randomised fashion, whereby the
random pattern was checked over and changed to avoid a particular glove type always being in a
particular position. In an attempt to double blind the experiment, both the participants and the
principal researcher were blinded to which gloves were being used. The gloves were numbered 1-4
and placed into separate bags by a separate party. Thus, it was unknown which glove belonged to
which brand until the end of the study, an approach suggested by Watson et al. (151). However, the
gloves are distinct colours with NBR being blue and NRL being white/beige, thus the particular glove
material was identifiable when watching the video footage. Nevertheless, the inner coating was not
determinable by the colour without prior knowledge.
63
Figure 4.6. Schematic of the equipment set-up for capturing the donning and doffing process.
Participants
Participants were recruited from a forensic drug analysis laboratory (SOCOTEC, Burton-on-Trent, UK)
where the analysis took place. These participants routinely don gloves, using on average 10-15 pairs
of gloves per day. A total of 14 participants took part in the study, seven of which were male, and
seven were female. The ages of the participants ranged between 22-40 and had all consented to
being recorded and had no known allergies to NRL. It was determined that measuring the glove size
and matching that to the HSE recommended size would not be representative of what occurs when
gloves are selected. Consequently, all participants were given the option of selecting the size of
gloves based on their own perception of what was ‘best-fit’. That is, the participants selected the
glove size based on the fit they were used to routinely. Participants hands were measured, using a
tape measure, for the length (from the tip of the middle finger to the wrist), width (across the top of
the palm), and circumference (measuring around the palm) by adapting a procedure used in Jee and
Yun (187). Ethical approval was obtained from the University of Sheffield Department of Mechanical
Engineering (No: 022731).
4.3.3 Questionnaire
As the participants in this study were experienced glove users, it was thought best to get their
perceptions of the donnability and doffability of the gloves. This questionnaire was conducted for
two reasons, to correlate perception with the results, and to assess preference correlation to results.
The latter arising due to previous focus studies concluding that preferred glove types are seen to
have better performance (7). As gloves and hand size were measured to assess whether the glove
being donned was appropriate, the participants were also asked about the fit of the gloves (did the
glove fit well?). To simplify, the questions asked were short, to the point and required a ‘yes’ or ‘no’
answer. This was asked after each test was conducted. The questions were as follows:
64
• Did the gloves fit well?
• Were the gloves easy to don?
• Were the gloves easy to doff?
4.3.4 Friction
Friction measurements
The friction between the skin and the gloves was measured for the same two hand moisture
conditions used when assessing the donning. A multiaxial force plate (AMTI) was used (15cm × 15cm)
to measure the friction between the skin and each glove. The force plate measures the force applied
(Z) and the frictional force in both directions of the plate: side-to-side frictional force (y) and forward-
backward frictional force (x), as shown in Figure 4.7. The force measured in the opposite direction of
the sliding is the ‘frictional force’ (the force opposing the movement), whereas the force applied is
the ‘normal force’ which is the vertical force utilized by the user pressing their finger down onto the
plate.
(a) (b)
Direction
of travel
Figure 4.7. a) AMTI plate with glove attached, arrow shows the direction of finger travel, and b) the direction
of forces with the z force as the normal load, the y force is the lateral (sideways) force across the plate and x
is the force of the direction of the finger being dragged along the glove.
Friction Methodology
Each glove was cut open and fastened to the force plate using double sided tape to secure the glove
completely to the plate, ensuring no relative movement, as in Figure 4.7. The exposed glove surface
was the inner ‘donning’ side. To assess the frictional interaction between the finger pad and the
gloves, the angle between the finger and the surface was kept at around 40o and the finger pad was
dragged along the plate, inducing a sliding action. Attempts were made with the palm of the hand,
but the force plate was not large enough, and it was thought that the glove is rarely in contact with
65
the whole hand during the donning process, due to the gloves being pulled and stretched. Thus, only
the index finger of the participants was used to assess friction as used in previous studies (90, 116).
The index finger of each participant was placed onto the glove and held at the desired force for 2-3
seconds before sliding was initiated. Participants were instructed to drag their finger down the glove
for around 8-10 seconds, which results in a sliding speed of around 1.2-1.5 cm/s. Participants
repeated each test three times in each condition (wet and dry). Previous studies had participants wet
their hands and then don gloves (15, 119, 120, 179, 180). However, hands would be dried more
rigorously prior to donning. Therefore, in this study, the wet condition was achieved by dipping the
finger (as friction is only being assessed with the finger) in warm water at 30-32 °C and then blotting
with a paper towel to remove most surface water. This was to recreate the act of drying the skin
after washing the hands in tap water (181, 188). However, some moisture was still visible on the
finger surface, as with the glove donning assessments. Ethical approval was obtained from the
University of Sheffield Department of Mechanical Engineering (No:022735).
Participants
Four participants were recruited for the friction analysis (2 males and 2 females, aged 25-34). The
participants were not the same participants used in the donning analysis due to participant
availability.
Load selection
Five loads were used to assess the frictional properties, these were 0.1, 0.25, 0.5, 0.75 and 1 N. These
loads were selected based on the load ranges used in the literature looking at the friction between
glove materials and skin (57, 137, 174). However, this study looked at multiple loads as an
assessment of different areas of the skin-glove interaction. A force of 1 N is similative of gripping and
holding, thus has been selected as the highest load (189). At the fingers, the force will be higher as
they have most contact due to the hand being forced into the glove. The low loads in this study
represent the interaction between the glove and the palm/back of the hand region/side of the palms,
which tend to have the glove stretched over them with little contact, until the fingers reach the end
of the gloves.
Moisture measurements
MoistSense (Moritex, USA) was used for moisture measurement in the outer layer of the skin known,
as the stratum corneum (Figure 4.8) (190). Moisture measurements were taken on the centre of the
66
index finger three times for each friction test conducted. The moisture measurements were only
taken for the friction tests, to highlight the difference in moisture.
Figure 4.8. MoistSense used to measure the moisture in participant’s skin.
4.3.5 Data Analysis
Friction analysis
As the donning procedure is a dynamic system (i.e. the hand and the glove move over each other in
order to don the glove), dynamic friction has been measured. The dynamic friction has been
calculated from a period where there is a plateau in the friction force, as shown in Figure 4.9, which
shows an ideal graph with easily identifiable difference between the friction types.
Normal Force Frictional Force

1.6
1.4
1.2
Static
1
Force (N)
0.8
0.6
0.4 Dynamic
0.2
0
0 2 4 6 8 10 12
Time (s)
Figure 4.9. Typical graph for determination of friction coefficient. Dynamic CoF has been taken from
the plateau in the normal force.
For analysis, the resultant horizontal friction force was calculated to account for any changes in local
deformation (as the finger moves bulk-wise on the glove in the same direction) and for the misalignment of
sliding (191). Resultant horizontal friction force was calculated using the equation:
2
𝑅𝑒𝑠𝑢𝑙𝑡𝑎𝑛𝑡 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑓𝑜𝑟𝑐𝑒 (𝑁) = √𝑥[𝑁]2 + 𝑦[𝑁]2
Equation 4.2
67
where x is the friction force moving up and down the force plate, and y is the friction force moving side to
side (Figure 4.7b). Coefficient of friction (CoF, µ) was then calculated via the equation:
Resultant friction force (N)

µ=
Normal force (N)
Equation 4.3
Power law relationships between the skin and glove friction have been previously reported in literature (90,
103, 107). Power fit laws have been applied to the data to obtain the best-fit lines for the trends using
the formula:
𝑃𝑜𝑤𝑒𝑟 𝐿𝑎𝑤 𝐹𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝐹𝑜𝑟𝑐𝑒 = 𝑎 + 𝑏𝑁 𝑛

Equation 4.4
where a and b are constants determined by the data, N is the normal force, and n is the exponent
determined by the data set.
Statistical analysis
The Shapiro-Wilk test for normality was used to assess the data for normal distribution (192). Data
which was found to be normally distributed was analysed using one-way analysis of variance
(ANOVA). This test looks to see if there are significant differences between all data sets (193). If
significance was determined by the ANOVA test, a further post-hoc Tukey’s Honestly Significant
Difference (HSD) was conducted (194). If the data was found to be non-parametric, significance was
tested for via the Kruskal-Wallis method (195). The non-parametric post hoc test chosen for this is
the commonly used Dunn’s Multiple Comparison Test (195). Statistical differences between the dry
and wet conditions for each glove was assessed using a two tailed paired t-test (where parametric) or
Wilcoxon Signed Ranks Test (where non-parametric) (196, 197). The significance level for the data
being significantly different is set at α=0.05. Thus, probability values (p), which indicate the
significance of the test, must be <.05 in order to be defined as statistically significantly different.
4.4 Results
4.4.1 Glove properties
The average glove thicknesses at each measured location are shown in Table 4.1, along with the
average thickness. It was found that the gloves have a tendency be thicker at the fingers than the
68
palm. The gloves have a similar thickness overall, with the exception of the chlorinated NBR, which is
just over half of the thickness of the polymer coated NBR gloves, on average.
Table 4.1. Gloves used and thickness measurement.

Average Thickness (mm)
Glove ID Treatment
Palm Finger Fingertip Average
0.06 0.06 0.08 0.07
Cl NBR Chlorinated
(0.006) (0.003) (0.005) (0.005)
0.10 0.13 0.15 0.13
PC NBR Polymer
(0.011) (0.006) (0.006) (0.007)
0.09 0.12 0.12 0.11
Cl NRL Chlorinated
(0.010) (0.005) (0.006) (0.008)
0.10 0.11 0.13 0.12
PC NRL Polymer
(0.012) (0.006) (0.007) (0.008)
 denotes standard deviation. Cl = Chlorinated, PC = Polymer coated
Physical properties
The gloves show differences in the break force, tensile strength, and elongation at break. It would
appear that the greatest tensile strength is present in the PC NBR (33.40 MPa), which also has a large
elongation at break (516%), as shown in Table 4.2. The greatest differences in the gloves are
exhibited with the elongation at break. The NRL, when chlorinated, was shown to have the highest
elongation at break (846%), whereas the least was the NRL when polymer coated (275%).
Table 4.2. Measured physical properties of gloves.

Fb (N) Ts (MPa) Eb (%) K
Glove
(N/mm)
6.25 25.77 442.00 0.022
Cl NBR
(0.68) (5.26) (79.38) (0.002)
9.53 33.40 516.42 0.024
PC NBR
(1.69) (5.00) (47.05) (0.002)
8.62 23.20 846.08 0.009
Cl NRL
(0.60) (1.59) (77.28) (0.002)
7.53 22.73 275.92 0.012
PC NRL
(0.50) (1.47) (142.39) (0.001)
 denotes standard deviation
Contact angles
The results obtained from the contact angles over the strain range showed similar results between
strains for each glove type, with no statistically significant differences following ANOVA (Cl NBR
F(2,6)=1.036, p=.411; PC NBR F(2,6)=0.087, p=.918; Cl NRL F(2,6)=0.116, p=.892; PC NRL F(2,6)=0.124,
p=.886). This indicates that there is no difference in the contact angle of water when the gloves are
69
strained. Thus, the results were collated, and are shown in Figure 4.10, as an average of the 9
measurements. The contact angles of the NBR show a good surface wettability, shown with contact
angles less than 90°. This shows that the NBR material has a hydrophilic nature. The paired t-test
shows no differences in the contact angles between the two NBR gloves (t(8)=-0.029, p=.977), with
the contact angle for chlorinated averaging at 43.78° (±8.63) and the polymer coated glove averaging
at 43.89° (±7.77). The NRL materials, on the other hand, is shown to have a hydrophobic nature, with
contact angles greater than 90°. This shows poor surface wettability across both coatings. There are
slight differences with the polymer coating having a slightly higher contact angle (121.78° ±5.25)
when compared to the chlorinated glove (121.78° ±5.74). However, the contact angles are not found
to be significantly different following a paired t-test (t(8)=-1.612, p=.212).
140
120
100
Contact Angle (°)
80
60
40
20
0
Cl NBR PC NBR Cl NRL PC NRL
Glove
Figure 4.10. Contact angles of DI water on the inside of each glove. Error bars indicate standard error.
4.4.2 Glove size and fit
Glove size
The results from the measured glove sizes are displayed in Table 4.3. As only medium and large
gloves were used in this study, only those have been measured and included here.
70
Table 4.3. Measurements of gloves used in this study.
Glove Glove length (cm) Finger to Knuckle (cm) Palm width (cm)
Type M L M L M L
24.7 26.3 8.1 9.0 9.2 9.4
CL NBR
(0.18) (0.12) (0.10) (0.23) (0.08) (0.25)
24.2 25.9 7.6 7.9 9.2 10.2
PC NBR
(0.21) (0.15) (0.19) (0.15) (0.03) (0.21)
24.8 24.9 7.8 8.3 9.3 9.7
Cl NRL
(0.25) (0.18) (0.12) (0.11) (0.21) (0.31)
25.3 25.3 8.0 8.3 9.5 10.2
PC NRL
(0.12) (0.17) (0.18) (0.16) (0.18) (0.20)
24.75 25.60 7.88 8.38 9.30 9.88
Average
(0.45) (0.62) (0.22) (0.46) (0.14) (0.39)
 denotes standard deviation
Glove fit
The participants perceived best-fit of gloves were compared against the HSE recommended size in
Table 4.4. There was one participant who had a recommended size which matches their perceived
best fit, and one participant wore gloves that were a size smaller than that recommended, based on
the sizing of their hands. The remaining 12 participants had a preference to wear gloves that were
larger than recommended based on their finger and/or palm size.
Table 4.4. Comparison of perceived best fit gloves used by participants to HSE glove size
recommendations from hand sizing (149).
HSE recommended size

Perceived best fit size
Finger Palm
M S S
L S M
M M M
L L M
M M S
M S S
M S S
M S S
M S M
M S M
L L XL
L M L
M S S
M S S
S = Small, M = Medium, L = Large and XL = Extra Large.
71
4.4.3 Donning and doffing
Donning steps
Upon analysing the videos, it was noticed there were four key steps to donning a glove. The first step
is picking up the glove(s). Participants were instructed to don and doff the gloves in the manner they
normally would and reminded that this was not competitive. Nevertheless, it is viewed that the time
taken to pick up the glove does not affect the key donning action, as picking up the glove does not
affect the act of donning. Thus, for the purpose of this study, the time taken to pick up the gloves has
been removed for analyses. The remaining three steps consist of the following:
• Preparation: This is the time taken to orient and mechanically separate the glove whilst
preparing to insert the hand (Figure 4.11a).
• Hand insertion: This is the time taken for the fingers to reach the end of the fingertips of the
glove (i.e. the hand is fully inserted into the glove) (Figure 4.11b).
• Material pulling/Glove manipulation: This is the total time taken to manipulate the glove
after hand insertion. These actions consisted mostly of manipulating the cuff/unrolling the
cuff and pulling the glove to ensure fit (Figure 4.11c).
(a) (b) (c)
Figure 4.11. Glove donning steps. (a) shows the preparation step, opening the glove, (b) shows the
hand insertion step and (c) shows the pulling of material down the fingers to comfortably fit hands.
Donning
In all cases, there were no large differences between the left and right hands. Thus, the time taken to
don a glove has been averaged, and the results presented show the time taken to don one glove
only. Figure 4.12 shows the average of the results obtained, broken down into the three stages of
donning in both the dry and wet hand conditions. The results show that chlorinated NBR and
72
polymer coated NRL were the quickest to don overall when the hands were dry, taking 3.99 (±1.18)
seconds and 4.00 (±1.71) seconds, respectively. When the hands were wet, the gloves took longer to
don, and there were more visible issues with the gloves, such as sticking to the fingers. Paired t-tests
show that the differences between the time taken to don the gloves in both hand conditions was
statistically significant for the chlorinated NBR and NRL, as well as the PC NBR (p<.05, Appendix B1).
The polymer coated NRL gloves were the quickest to don when wet (4.83 (±2.74) seconds), and there
is no significant difference between the dry and wet conditions (t(13)=2.160, p=.124). Table 4.5
shows the results from conducting ANOVA on all gloves, in both conditions. No significant differences
were observed between any of the gloves at any of the three stages in the both the dry and wet
conditions (p>.05). Differences were, however, found in the total time taken to don the gloves in the
dry condition (F(3,52)=-4.283, p=.009). Tukey’s (HSD) tests were further conducted on the total time
in the dry condition, which showed statistically significant differences between Cl NBR and PC NBR
(Q=4.130, p=.026) as well as PC NRL and PC NRL (Q=4.552, p=.012). The results of these tests are
shown in Table 4.6. Paired t-tests on the dry and wet conditions for each glove reveal that the largest
differences are present in the ‘hand insertion’ step, as the time taken was significantly increased for
each glove (p<.05. Table 4.7).
* Indicates statistical significance (p<.05)

Figure 4.12. Average times taken to don the medical gloves broken down into the three key tasks.
Error bars denote standard error.
73
Table 4.5. Results of ANOVA/Kruskal-Wallis test conducted across the total donning time, and each
step of the donning process in both dry and wet conditions.
Result
Donning stage
Dry Wet
Total F(3,52)=4.283, p=.009* F(3,52)=1.876, p=.176
Preparation F(3,52)3.399, p=.101 F(3,52)=3.992, p=.054
Hand insertion F(3,52)=1.907, p=.340 H(3,52)=0.289, p=.529 A
Manipulation H(3,52)=3.191, p=.717 A F(3,52)=1.122, p=.329
* Indicates statistical significance (p<.05). A Denotes the use of Kruskal-Wallis test due to non-
parametric distribution of data.
Table 4.6. Post Hoc Tukey’s test results conducted on the total time in the dry condition (ANOVA=
.009).
Glove
PC NBR Cl NRL PC NRL
Q=4.130 Q=0.721 Q=0.4219
Cl NBR
p=.026* p=.900 p=.900
Q=1.142 Q=4.552
Glove PC NBR
p=.086 p=.012*
Q=3.410
Cl NRL
p=.834
* Indicates statistical significance (p<.05).
Table 4.7. Results of paired t-tests comparing dry to wet in all glove types at each step of the donning
process.
Glove
Donning stage
t(13)=-1.224 t(13)=-0.354 t(13)=-0.387 t(13)=-0.209
Prep
p=.183 p=.682 p=.647 p=.884
Hand W(13)=8 W(13)=5 W(13)=5 W(13)=10
insertion p=.013* A p=.013* A p=.002* A p=.002*
t(13)=-1.537 W(13)=5 t(13)=-0.424 W(13)=35
Manipulation
p=.118 p=.083 A p=.577 p=.395 A
A
* Indicates statistical significance (p<.05). Denotes the use of Wilcoxon-signed ranks test due to non-
normal distribution of data.
Doffing
Figure 4.13 shows that the time taken to doff the gloves had an average time range of 1.68-1.93
seconds across the eight conditions. When the hands were wet, there was a slight increase in the
average time taken to remove the gloves, with the exception of PC NBR, where the time taken to
remove decreased, on average (dry= 1.93s ±0.29; wet= 1.84s ±0.65). Paired t-tests show there are no
significant differences between the any of the hand conditions (p>.05, appendix B2). ANOVA also
74
reveal that there is no significant difference between all gloves in either the dry (F(3,52)=1.250,
p=.301) or wet (F(3,52)=0.011, p=.999) conditions.
Dry Wet
2.50
0.457 0.407 0.908 0.402
2.00
1.50
Time (s)
1.00
0.50
0.00
Glove Sample
Figure 4.13. Average results of time taken to doff the medical gloves, with paired t-test (p-value)
results between the two conditions Error bars denote standard error.
4.4.4 Gloves sticking incidence
As hands were placed into the glove, it was observed that on several occasions the gloves stuck to
the fingers in localised areas, decreasing the efficiency of placing the glove on the hand. These
incidences of sticking were noted down for each glove. A sticking incidence was noted when the
glove was being pulled by the participant, but there was no movement of the overall glove. In some
cases, these sticking incidences were quickly fixed by harder pulling of the gloves, which lasted
around 0.1-0.2 seconds. In other cases, the gloves required total cessation of the pulling action, to
manipulate the glove and pull the specific areas. A total of 329 incidences of sticking were noted
across the 14 participants. Figure 4.14 shows the different hand locations where sticking was
observed. This was formulated based on the common areas where the fingers became stuck to the
hand. It is important to note, that only one finger may have been stuck in any of the locations. All
locations have been labelled the same across the fingers for the sake of visual simplicity. In all the
gloves, there was a greater frequency of sticking/high friction at the section at the top of the palm
(location D) and the proximal location of the fingers (location C). The number of incidences of sticking
increased in the wet condition, due to the increased moisture causing adhesion (Figure 4.15).
75
Figure 4.14. Map of the glove showing areas where sticking of the fingers/hand occurred on the
glove throughout the study.
60
I
50 G
F
I
E G
I E
No of Sticking occurrence
40 H I
E I G
I F
D F I E
D G D
30 I F E H
F E
E F
D
E
D
20 C D
D C C D
C
C
10 C B B C
C B
B
B B B
A A B A
A A A A A
0
Dry Damp Dry Damp Dry Damp Dry Damp
Glove/Condition
Figure 4.15. Incidences of sticking in the different areas within all of the gloves shown in Figure 4.14.
4.4.5 Perception of fit, donning and doffing

Results from the participant questions after donning/doffing the gloves are shown in Figure 4.16. The
graph shows how many responded ‘yes’ to the questions asked. Chlorinated NRL has a good overall
reported fit with 9 out of the 14 participants responding that the glove fit well. On the other hand,
the polymer coated NRL gloves had the poorest reported fit with only 4 participants responding that
76
the fit was good. When the hands are wet, the gloves were perceivably harder to don with only two
respondents stating that both of the PC gloves were easy to don. However, the chlorinated gloves
were perceived to be harder to don with only one participant stating that the chlorinated gloves
were easy to don when the hands were wet. On the other hand, doffing the gloves had no significant
impact on the user perception. The chlorinated NBR was perceived to be slightly less easy to don
when the hands were wet. However, the polymer coated NRL was shown to increase from 12 people
finding it easy to doff to 14 when the hands were wet.
14
12
Participant Response
10
0
Dry Wet Dry Wet
Fits well Easy to Don Easy to Doff
Figure 4.16. Responses of the participant questionnaire regarding the fitting of the gloves and the
ease of donning and doffing.
4.4.6 Friction
Data has been processed and only graphs are shown in this section. All calculated CoFs for each load,
complete with the statistical analysis conducted is included in the appendix (B3-B5).
Moisture
The readings produced from the MoistSense give a reading in Arbitrary Units (A.U). A reading of 0-40
means the skin is lacking in moisture and is dry. When between 40-70 the skin is at a healthy
moisturised state, whilst a reading over 70 suggests the skin contains more moisture than the natural
state. As participants had similar skin moisture results across each of the gloves, averages have
displayed for each participant (Figure 4.17). The results were similar for each participant in the dry
section, showing a healthy dry skin around 57-61 A.U. The wet skin moisture results were
significantly higher in each participant (94-98 A.U) following paired t-tests (P1: t(11)=22.411, p=<.01;
P2: t(11)=-24.740, p=<.01; P3: t(11)=-61.660, p=<.01; P4: t(11)=-53.334, p=<.01).
77
Dry Wet
100
90
80
Moisture (A.U)
70
60
50
40
30
20
10
0
P1 P2 P3 P4
Participant
Figure 4.17. Average moisture per participant across the 4 gloves. Error bars denote standard error.
NBR friction
The results obtained from the friction between the skin and NBR are shown in Figures 4.18 (a-h). In
all instances, the friction increases with increasing load, leading to a lower CoF as the load increases.
It is clear from the data that the inclusion of moisture causes an increase in friction with both the
polymer coated and the chlorinated gloves. Most significant differences between the wet and dry
friction were noted in the polymer coated gloves (p<.05). The statistical analysis for these datasets is
included in the appendix (B2-3). In the wet hand condition, there was little difference between
friction observed between the chlorinated and polymer coated gloves, with very little statistical
differences amongst the participants following paired t-tests across all loads (p>.05). However,
significant differences were found between the friction of the two coatings in the dry condition
(p<.05). The statistical analysis for these datasets is included in the appendix (B2). In the wet
condition, more friction was present in the polymer coated, which is converse to what is expected to
happen, as the polymer coating is said to reduce friction to enable a smoother donning process. At a
low load when wet, the highest friction coefficients are observed between all participants (µ=5.17,
6.73, 6.50 and 8.81, respectively). In addition, stick-slip was identified in some participants in the
polymer coated gloves. As the load increases, the CoFs become quite similar across the gloves, but
chlorinated dry glove has a tendency of producing the lowest friction across the gloves, with CoFs
ranging between 3.79 and 1.1.
78
a) Participant 1 b) Participant 1
3 10
8
Friction Force (N)
2
6
Cl Dry Cl Dry
CoF
Cl Wet Cl Wet
4
1 PC Dry PC Dry
PC Wet PC Wet
2
0 0
0.0 0.4 0.8 1.2 0.0 0.4 0.8 1.2
Load (N) Load (N)
c) Participant 2 d) Participant 2
3 10
8
Friction Force (N)
2
6
Cl Dry Cl Dry
CoF
Cl Wet Cl Wet
4
1 PC Dry PC Dry
PC Wet PC Wet
2
0 0
0.0 0.4 0.8 1.2 0.0 0.4 0.8 1.2
Load (N) Load (N)
e) Participant 3 f) Participant 3
3 10
8
Friction Force (N)
2
6
Cl Dry Cl Dry
CoF
Cl Wet Cl Wet
4
1 PC Dry PC Dry
PC Wet 2 PC Wet
0 0
0.0 0.4 0.8 1.2 0 0.4 0.8 1.2
Load (N) Load (N)
79
g) Participant 4 h) Participant 4
3 10
8
Friction Force (N)
2
6
Cl Dry Cl Dry
CoF
Cl Wet Cl Wet
4
1 PC Dry PC Dry
PC Wet PC Wet
2
0 0
0.0 0.4 0.8 1.2 0 0.4 0.8 1.2
Load (N) Load (N)
Figures 4.18 a-h. Average friction and the CoF of chlorinated and polymer coated NBR gloves across
all participants. Error bars denote standard deviation.
4
Stick-slip
3.5
2.5
Force (N)
2
Normal Force
1.5 Horizontal Force
1
0.5
0
0 2 4 6 8
Time (s)
Figure 4.19. Example of the stick-slip induced by the rapid alternation between static and dynamic
friction.
NRL friction
Figures 4.20 (a-h) show the friction forces and the CoFs of the skin-glove interactions with the NRL
gloves. The NRL friction shows to have differing behaviours to the NBR, with the friction produced in
both the wet and dry being generally lower than the friction produced in the NBR material. In most
cases, CoFs between the skin and gloves increased upon the addition of moisture, with some
statistically significant differences observable with the chlorinated glove samples. Full statistical tests
80
are shown in the appendix (B4-5). With participant 1 there is very little fluctuation in CoF as the load
increases. T-tests show little difference between the gloves in all participants (p>.05). However,
across all participants in the wet condition, significant difference is noted between the polymer
coated films and the chlorinated films in all participants at the lowest target load (p<.05), as noted
with the NBR. In general, the friction of the polymer coated gloves is lower in the dry condition with
the lowest CoF observed in the 0.5 N target load in participant 1 (µ=0.88). The increase of friction
once moisture is introduced is minimal in the polymer coated gloves when compared to the
chlorinated. For example, with participant 3, the polymer coated gloves show an average CoF
difference of 0.06 between the wet and dry conditions at the highest target load (1 N). On the other
hand, in the chlorinated gloves, there is a CoF difference of 0.66. No significant differences were
found between the CoFs in the wet and dry conditions following paired t-tests (p>.05) however
differences were noted in some of participants friction in the chlorinated samples. These significant
differences were mostly observed at the higher loads (appendix B4). Stick-slip was also observed with
the NRL gloves, however, this time participants had stick-slip observed in the chlorinated gloves,
rather than the polymer coated as seen in the NBR.
3 6
5
Friction Force (N)
2 4
Cl Dry Cl Dry
CoF
3
Cl Wet Cl Wet
1 PC Dry 2 PC Dry
PC Wet 1 PC Wet
0 0
0.0 0.3 0.6 0.9 1.2 0.0 0.3 0.6 0.9 1.2
Load (N) Load (N)
81
3
6
5
Friction Force (N)
2 4
Cl Dry Cl Dry
CoF
Cl Wet 3
Cl Wet
1 PC Dry 2 PC Dry
PC Wet PC Wet
1
0 0
0.0 0.3 0.6 0.9 1.2 0.0 0.3 0.6 0.9 1.2
Load (N)
Load (N)
3 6
5
Friction Force (N)
2 4
Cl Dry Cl Dry
CoF
3
Cl Wet Cl Wet
1 PC Dry 2
PC Dry
PC Wet 1 PC Wet
0 0
0.0 0.3 0.6 0.9 1.2 0 0.3 0.6 0.9 1.2
Load (N)
Load (N)
g) Participant 4 h) Participant 4
3 6
5
Friction Force (N)
2 4
Cl Dry Cl Dry
CoF
3
Cl Wet Cl Wet
1 PC Dry 2 PC Dry
PC Wet 1 PC Wet
0 0
0.0 0.3 0.6 0.9 1.2 0 0.3 0.6 0.9 1.2
Load (N) Load (N)
Figures 4.20 a-h. Average friction and the CoF of chlorinated and polymer coated NRL gloves across
all participants. Error bars denote standard deviation.
82
4.5. Discussion
4.5.1 Donning and friction
Of the gloves used in this study, it is shown that there is little difference between the time taken to
don the different glove materials, with different coatings, when the hands are dry. The longest time
was shown in the polymer coated NBR glove. It is evident from the results, that participants generally
take longer to don the gloves when hands are wet. This reflects the issue of donning gloves with
sweaty or wet hands from washing (15, 57, 120). The polymer coated NRL was the only glove type
found to be unaffected by moisture changes, as indicated by the lack of a statistically significant
difference between the two hand conditions
When broken down into the three key steps present within donning, statistically significant
differences were found between the polymer coated NRL when compared to the other gloves in the
wet hand condition. This further indicates that this glove was quicker to don than the other glove.
Statistically significant differences were present mostly in the preparation stage when the hands are
wet. This is likely to be due to participants not being able to grip and/or open the gloves as efficiently
than with the dry hands. There are also large variations in the hand insertion step, due to the glove
sticking to the skin or fingers getting stuck in the glove. There is a greater frequency of sticking/high
friction at the section at the top of the palm (location D, Figure 4.14) and the first location of the
fingers (location C, Figure 4.14). This could be due to a combination of the nature of glove packaging
as well as the behaviour of the participants when donning the gloves. Medical gloves are normally
compressed into boxes for packaging (14). In some cases, this causes the inner surface of the gloves
to stick together, which are only separated by mechanical action prior to donning the glove or whilst
the glove is being donned. Separating the glove to insert the hand takes time, and when the gloves
are manipulated by the participants in the preparation stage, the participants tended to open the
glove, either by rubbing or pulling the glove, at the palm or cuff only. The sticking and friction with
the skin then occurs as the participant opens the finger holes using their fingers once the hand is in
the glove. This appears to be more problematic in the wet hand condition, led by the adhesion of the
glove to the skin surface. As the finger slides up and into the finger region of the glove, more friction
is likely as there is larger contact area with the hand, than at the opened palm. Manufacturers may
dip their gloves in silica to aid reinforcement of their tensile properties, prior to the chlorination step,
which changes the properties between gloves of the same bulk material. Also, in the case of NRL, this
further prevents latex allergies arising. Manufacturers may also use different chlorination strengths
and exposure times. These can all impact the final physical properties of the gloves (14, 38, 198).
83
The time taken to don the gloves has some correlation to the results obtained from the
friction study. There is little difference between the chlorinated and polymer coated friction in the
dry state with the NBR gloves. However, in both the NRL and NBR gloves, a higher friction coefficient
is induced when moisture is applied. The way the moisture reacts to the material strongly influences
the friction. NBR, by nature is polar, whereas NRL is non-polar. Thus, when moisture is introduced, it
would be expected to have slightly differing frictional behaviours because of the material interaction.
The goniometer results show clear differences in the way the water is interacting with the NBR and
NRL surfaces. In the NBR gloves, a low contact angle is observed. This means that there is a high
surface energy, which pulls the moisture towards the surface, inducing more wetting (hydrophilic).
This moisture addition creates local welding and more interaction with the glove surface will be
present via electrostatic interaction (121). The NBR pulling the liquid to the surface causes more
contact area with the finger, which increases friction, as shown in Figure 4.21a. Thus, the increased
time taken to don the PC NBR glove could be due to the hydrophilic nature of the coating itself,
which is used to aid donning, rather than hinder it. On the other hand, the NRL glove exhibits a high
contact angle, showing a low surface energy which leads to a low surface wetting (hydrophobic). This
means the water would have a stronger affinity for the skin, causing a separation of the skin-glove
surfaces and adding lubrication to the system, as shown in Figure 4.21b. This allows for the skin to
glide smoothly, allowing a quicker donning of the NRL glove, when compared to the NBR. In the NRL,
the polymer coating exhibits the lowest friction amongst the participants, which is not highly
impinged by the addition of moisture. This difference in friction between the chlorinated and
polymer coated NRL gloves is also observed by Roberts and Brackley (137), who obtained friction
coefficients of 0.15 for polymer coated and 0.5 with chlorinated gloves at 0.32 N. In this study,
friction coefficients for the gloves are found to be much higher. The average CoF for chlorinated
gloves in all participants at 0.32 N (following the trendlines) is in a range between 1.23 and 4.03. The
CoFs for the polymer coated gloves were also found to be much higher than in the previous study
(between 1.12 and 1.23). However, it is unknown what polymer coating has been used in either of
the studies.
84
(a) (b)
NBR NRL
Figure 4.21. Interaction between different glove surfaces when water is introduced. NBR brings the
finger to the surface due to the polar nature, whereas NRL repels water, causing it to lubricate.
The explanation behind the proposed interactions can be further evidenced by the friction graphs.
Figure 4.22 shows a typical graph of the glove friction obtained in these results. In some participants,
after a few seconds, friction started to increase in all gloves when moisture was added. This was
predominantly observed in the NBR gloves, more so with the polymer coated, as the hydrophilic
nature allows spreading of the moisture, ultimately increasing the skin-NBR contact area. In the NRL
gloves, this was more apparent at the higher loads, as the moisture is pushed out of the side of the
finger, inducing more contact area.
Figure 4.22. Friction of PC NBR gloves showing how the moisture changes in the wet condition
increase friction overtime as a sliding interaction with the glove spreads moisture away from the
finger surface in contact.
It is also important to note, that the process of coating NBR gloves is not as straight-forward as
coating NRL gloves. Close attention needs to be paid to the surface tension of the wet NBR film.
Without adequate modification of this surface tension, the polymer coating deposited onto the film
can be distributed with an uneven thickness (14, 199). In conjunction with this, high surfactant
85
content from the NBR gloves can leach into the polymer coating bath, causing issues whereby the
coating does not bind well to the surface (200). However, these issues are not widely discussed in the
literature. This could be one of the reasons for the polymer coated NBR gloves to have higher CoF
than the polymer coated NRL.
Morphological changes
Changes in the morphology in the finger throughout the study in both the dry and wet conditions can
contribute to slight differences in frictional properties, a variable factor in this study (108, 121, 201).
Repeated wetting of the skin fingertip could cause wrinkling of the skin, affecting the contact area
and overall frictional properties of the skin. Although this was not visibly noticed, and there was little
constant exposure to water/breaks between friction tests, there is still the possibility of micro-
wrinkling having an impact on the results (183). As low loads are used in this study, the small changes
in the skin topography could have an impact on these results.
Secretion-water interaction
The differences in the donning time and friction in some of the participants may be attributed to skin
contaminants. Skin, by nature, contains secretions of moisture, salts, and lipids on the surface, from
the underlaying sweat glands (202). This sweat held on the surface can attract or repel the water,
causing differences in electrostatic properties, which could cause either a reduction or increase in
friction (203, 204). As the contaminants on the fingers interact with the water, two things could
occur, which are dependent on the volume of contaminants, and their affinity for the glove material
or skin. The sweat-water molecules could pull down towards the polymers, causing a spreading of
the moisture throughout the contact area and beyond as the polymer acts as a capillary. This would
lead to an increase in contact area as surface asperities are brought closer together, as well as
electrostatic interaction with the glove film.
The other mechanism could be a reduction in friction as the moisture stays on the skin
surface, causing more separation between the finger and the gloves. This would cause a more
complex interaction as the individual contaminants (oils and water) would separate, due to their
immiscibility. Although the hands were washed prior to testing there is no guarantee, when
conducting studies of this nature, that these contaminants were not present. It is possible that,
although small, the immiscibility of these contaminants from sweat contribute to the stick-slip
exhibited in some of the gloves. Stick-slip is defined as rapid alternation between the static and
dynamic friction. Derler and Rotaru (205) previously defined stick-slip as the measured CoF with a
86
greater than 10% variation, which was observed in some participants (as shown in Figure 4.19). This
means that both the donning and friction of the gloves is dependent on how much water the
materials will absorb/repel, the interaction between the water and the finger, and the presence of
oils/contaminants on the skins surface.
Perception
As discussed by Mylon et al. (7), the perception of performance with routine medical glove users is
normally indicated by preference. The gloves used amongst the participants in their daily work were
chlorinated NBR and NRL gloves. On average, chlorinated natural rubber NRL was perceived to be the
easiest to don, but the results indicate that those gloves took longer to don whist the polymer coated
NRL was the quickest. Some participants also stated that the polymer coated NRL gloves were harder
to put on because they felt thicker than any of the other gloves, but the thickness was similar to the
polymer coated NBR.
4.5.2 Doffing
Doffing was not viewed to be an issue in this study. The results showed no differences between the
gloves. There was an increase in the time taken to doff the gloves when moisture was present,
however, this increase was minor and had no significant differences. In the PC gloves, there is a
tendency for NBR to take longer to don when compared to NRL. This is presumably because of the
hydrophilic nature of the NBR being drawn towards the skin. This would mean there is likely a
stronger interaction brought about by electrostatic charges between the skin and glove, causing
more of a peeling action to remove the gloves. In the NRL, however, the moisture will be separating
the glove from the skin, leading to a smoother transition when removing the glove, as described in
the donning actions. Very few participants thought that the different glove materials and coatings
affected their ability to remove the gloves, indicating that doffing is not an issue with these glove
users. However, the gloves were removed soon after donning, it may be that when more sweat is
generated in the glove, issues with glove sticking to the hands could cause more adhesion, possibly
making it harder to doff the gloves. Most participants indicated that all the gloves were easy to doff,
but a few commented that the polymer coated gloves ‘felt thicker’ and perceived that to be a slight
hindrance upon removal.
87
4.5.3 Glove properties
The gloves have been tested under EN standards; however, it is not known how old the gloves are
before these tests were conducted. Donning assessments were carried out around 1 year prior to
testing the physical parameters, and it was unknown when the gloves were manufactured prior to
the donning testing. Gloves degrade over time, and the longevity of their physical properties is
dependent on the correct storage, light exposure (206) and relative temperature/humidity (207). It is
very likely that this is not a true representation of the properties of the gloves when formed. For this
reason, the physical properties were not checked for correlation between either the donning or
physical properties with these gloves. This is because it is thought that this is not replicable of what
the properties will have been when the tests were conducted.
The differences in thickness along the glove length can be explained by inverted nature of
the dipping process of the glove manufacture procedure. When gloves are made on the dipping line,
formers are dipped into the compounded glove material finger first, left for the dwell time (usually 5-
10 seconds), and then then pulled back out of the compounded material. Therefore, the finger areas
have a longer dwelling time in the material, and have more coagulated rubber onto the surface of
finger areas, which produces a thicker film when compared to the palm (14, 38).
Issues were noticed when donning the gloves, mostly around the rolling of the glove on the
back of the hand, as shown in Figure 4.23. This adds time to the ‘after manipulation’ stage of donning
as participants take the time to unroll the glove and bring the cuff up the wrist to complete the
donning process. This rolling was more commonly seen in the NRL gloves. As the glove begins to roll
up the back of the hand, the chlorinated NRL glove will continue to roll with it due to it being less stiff
and conforming more to the hand. The NBR material, however, is stiffer compared to that of the NRL
and appeared to roll on the back of the hand less frequently, and not as severely. The gloves were of
a similar thickness except for the chlorinated NBR which was almost half the thickness of the other
gloves on average. As there are no statistically significant differences between the dry handed
gloving conditions, it is indicated that the thickness of the glove is not a factor in this study. However,
the lack of difference could be due to the differences in skin-glove coating interactions. Further work
needs to be carried out to assess if, and how, the thickness of gloves affects the donning process.
88
Figure 4.23. Rolling of glove on the back of the hand when donning.
4.5.4 Fit
When compared to the recommended glove sizes by the HSE, the participants did not appear to wear
the correct recommended sizes. Seven out of the 14 participants wore a size larger than
recommended and only one participant wore the correct recommended glove size. The literature
shows that these gloves need to be a good fit to ensure maximum comfort, dexterity, and tactile
sensitivity (99). As there was a small amount of excess material around the fingers for three of the
participants, it was viewed that the gloves were larger than needed when fitted. These three
participants wore medium gloves and said that when smaller gloves are used, they are difficult to put
on and too tight once on. It would be expected that if the hands are smaller than the recommended
glove size, they would be easier to don. However, this is not the case as the time taken to don the
gloves were similar across all participants. It is clearly indicated from this study that the ‘best-size’ to
fit a participants’ hand has little relation to the recommended ‘best-fit’ gloves size.
4.6 Conclusions
A summary of the findings from this chapter are shown in Table 4.8. This shows the results of the
three tested parameters in this chapter, when comparing the wet hand to the dry hand condition. In
all of the tests with NBR, the wet hand complicates the process and increases the time taken to don
the gloves and increases friction.
89
Table 4.8. Findings of the chapter comparing the outcome of performance of the wet hand to the dry
hand condition.
Glove donned in the wet hand condition

NBR NRL
Measured
Chlorinated Polymer Coated Chlorinated Polymer Coated
parameter
Increases/Similar
Donning Time Increases Increases Increases
to dry
Doffing Time No difference No difference No difference No difference
Decreases/ Similar
Friction Increases Increases Increases
to dry
The conclusions of this chapter are as follows:

• When the gloves were donned in dry conditions, the performance times were similar across
the gloves. However, polymer coated NRL generally exhibited lower friction, had less
incidences of sticking, and took less time to don when the glove was wet. Little difference
was observed in the friction between the dry and wet conditions with the polymer coating in
the NRL, however greater differences were noted in the NBR, with the polymer coated
having greater friction, and the gloves took longer to don on average. The two chlorinated
gloves used had little difference in donning time, but lower friction was observed in the NRL
gloves.
• Doffing is not affected by glove material, coating, or hand condition. It could be that
prolonged periods of wearing could induce more sweat, making the gloves harder to remove.
This would be reflected by the ‘wet’ condition in this study, which shows no difference from
the dry condition.
• The entire donning process needs more thought in studies, other than just the frictional
properties. The nature of the material, size, fit and stiffness can all contribute to the glove
donning process, and cause problems, such as the glove rolling up the hands, or adhesion of
the gloves to the hands.
• There are issues with glove size amongst some glove users. HSE recommendations match
only one participant in both palm and finger sizes in this study. Some participants wore sizes
that were a little too big for their hands.
• Chlorinating gloves is extremely common, but the finishing processes are not widely revealed
to the purchaser/user. Manufacturers may dip their gloves in silica to aid the reinforcement
of their tensile properties, and some manufacturers may use different chlorination strengths.
Thus, the two chlorinated gloves in this study may not have had the same treatment.
90
Chapter Five: The effects of NBR glove properties on
donning
5.1 Introduction
In Chapter 4, it was shown that the choice of polymer coating in the NBR material was more
detrimental to the donning process than the chlorinated gloves. The study conducted, however did
not study the effects of the effects of thickness but indicated that there was little difference in results
regarding thickness in the dry condition (172). Nor did the experiments have the capability of making
the test fair, by comparing gloves that only differed by their raw materials and treatments/coatings.
When purchasing gloves, it is impossible, without the manufacturer’s information, to determine the
exact components used and the treatment methods. There are a range of ways manufacturers can
finish gloves. This includes dipping in silica to protect the physical properties, ranging chlorination
strengths and the length of exposure to the chlorination (14, 38, 198). A higher chlorination leads to
a smoother surface, reducing tack and ultimately reducing the friction (16, 173). However, there is
little to link this chlorination process to an easier donning process, especially in the way of human
skin friction in conjunction with the donning mechanisms (173). In order to study the effects of
chlorination with skin, gloves need to be made with the same materials.
5.2 Aim and scope

The aim of this study covered in this chapter was to investigate the effects of thickness, chlorination
strength, and moisture on the donning process. To study the effects of thickness and chlorination,
gloves needed to be sourced which had the same manufacturing profiles and only differed in surface
treatment and thickness. In order to obtain these, gloves had to be manufactured specifically for this
test. Due to the leaning of the sales market towards the NBR gloves, only this material was studied
for the effects of different chlorination strengths and thickness (38). As with Chapter 4, the donning
of gloves was assessed in both dry and moist conditions.
5.3 Materials and methodology

5.3.1 Glove manufacture
NBR gloves were produced in-house at the Technical Centre of Synthomer Sdn Bhd, Kluang, Malaysia.
The NBR films were formed using Synthomer 6348HS grade rubber, via two manufacture methods
which mimic the process used for standard glove manufacture, but on a smaller scale. Synthomer
91
6348HS is a colloidal suspension of carboxylated acrylonitrile butadiene, containing emulsifiers and
antioxidant stabilisers. The manufacture methods used in this study differed only by the dwell time
of the former dipped into the coagulant and the compounded NBR material, in order to create gloves
of two different thicknesses.
Glove formation
The NBR was compounded using the constituents shown in Table 5.1. Medium size porcelain glove
formers were placed into a mixture of calcium nitrate and calcium carbonate coagulant for three
seconds. The formers were then heat dried in a 65°C oven before being dipped into the compounded
NBR for a further three seconds (Figure 5.1). Following this, the formers were placed into an oven to
gel set at 100°C for one minute, before being dipped again for a further three seconds. This method
created the thinner of the two films. The thicker film was produced using the same approach, but
with double the dwell time (six seconds for compounding and dipping). After the gelling process, the
gelled films were manually beaded. The beading was achieved by rolling the end of the glove down a
few mm, which creates the cuff of the gloves. The films were then leached for one minute in water at
100°C and then left to cure at 100-120°C in an oven to create the finished glove. Due to the
availability of equipment and small-scale production, films were only manufactured on medium sized
formers.
Table 5.1. Components used to make compounded solution of the NBR material for the glove film
formation
Component Parts per hundred rubber (phr)

6348HS NBR 100
Potassium Hydroxide 1.2
Zinc oxide 1
Sulphur 0.8
Zinc diethyldithiocarbamate 0.7
Titanium dioxide 1.5
92
Dipping
machine
Former
Deposited NBR
(brighter
white)
Compounded NBR
Figure 5.1. NBR material coagulated on the former surface (covered by coagulant salts) to form the
wet NBR film.
Chlorination
For this research, the acidification process was used, as discussed in Chapter 2 (53). Sodium
hypochlorite and hydrochloric acid (HCl) were mixed to create the concentrations in large plastic
containers, in which the formers could be immersed. Chlorine solutions were created at
concentrations of 500, 1000, and 2000 ppm (parts per million of chlorine). These concentrations
were chosen based on the typical industrial practices reported in Ong (16). A quarter of the gloves
from each thickness variant were skipped for the chlorination process to serve as control for testing.
Formers containing the attached glove film were placed into the chlorine solutions for 10 minutes.
Following this, formers were then immersed in a neutraliser solution (sodium thiosulphate) for 6
minutes before being leached, at 60°C with hot water. This removes any chlorine residue on the film
surface. The films were then dried in an oven for 5 minutes at 100-120°C, before being removed from
the former. One of the aims of this study was to assess to what extent chlorination made the whole
donning process easier, including a control which had no treatment. However, the control gloves
were found to be hard to release from the formers and became overstretched/torn. Thus, the
control glove was covered in a light dusting of calcium carbonate, which helped release the glove
93
from the contours of the former. Attempts were made to keep the powder distribution minimal,
however, the fine powder is likely to still be present on the inner surface.
Glove characterisation
The gloves were characterised as in Chapter 4, using the same thickness and size, tensiometer and
goniometer measurements (see Section 4.4). As it was found that strain did not affect the contact
angle, these were measured with the gloves in the unstrained condition. Also, in this section, two
extra tests were conducted on the gloves: surface characterisation by surface roughness and Fourier
transform infrared spectroscopy (FTIR).
Surface Roughness
Surface roughness of the donning side of the gloves was measured using Alicona optical 3D
measurement. In Chapter 4, the ability to measure the surface roughness was not possible due to the
nature of the finish on the materials. As the finish on these gloves rendered a ‘duller’ surface finish,
roughness was able to be obtained. Two samples of approximately 4 × 4 cm samples were cut from
the finger area of two separate gloves. For surface analyses, 1.5 × 1.5 cm sections were scanned onto
the instrument to obtain an average surface roughness (Sa) of the gloves, with a 5x objective lens
with magnification between -1.46 – 15.85x, a lateral resolution of 2.89 µm, and a vertical resolution
of 900 nm.
FTIR
A Thermo Scientific (T1-139) Fourier transform infrared spectrometer (FTIR) was used to assess the
chemical differences on the inner (donning) surface of the different manufactured gloves. This was to
establish if there were any chemical differences between the gloves receiving different chlorination
strengths. Each sample was scanned 16 times in the 400-4000cm-1 region with a resolution of 4cm-1.
5.3.2 Experimental methodology

The donning methodology was completed following the same set-up and procedure as in Chapter 4
(see Section 4.4). This study was conducted in the same conditions; dry and wet. There are, however,
a few differences between this study and the one previously conducted in Chapter 4, which are as
follows:
• The participants donning the gloves were not regular day-to-day glove users but use gloves
1-2 times a week on average. Thus, perceptions of donning/doffing were not ascertained.
94
• Moisture was measured on the fingers, palm and back of the hand using a moisture sensor
before trying on each glove type in dry and wet conditions.
• A drawback of the in-house manufacturing was the time taken to produce gloves on a small
batch scale, resulting in a lower volume of gloves being manufactured. Thus, the number of
participants was less than half of that of the previous study (n=6).
• Friction was measured in the same way as previously (see Section 4.4.3). However only three
loads were tested to allow time to repeat tests in an efficient manner. The selected loads
were the low (0.1N), medium (0.5N) and high (1N) loads used in the previous study.
• An extra friction study was used to determine the effects of the sample properties on the
donning behaviour. This was conducted by only affixing the glove around the edges of the
force plate. This left the centre free to move with the fingers, allowing assessment of the
behaviour of the different sample thicknesses.
• The doffing of these gloves was not assessed due to it not being highlighted as an issue in
Chapter 3, nor were there any differences between gloves in the previous study.
Participants
For the donning part of this study, four males and two females participated in this experiment (n=6).
Ages ranged between 22-28, and they did not have any known skin issues or any allergies that could
be triggered by using gloves. Participants used gloves on average 1-2 times per week and had a
preference of wearing ‘medium’ sized gloves. Hands were measured in the same manner as the
previous methodology in Chapter 4 (see Section 4.4). Prior to being recruited, participants were
asked to don a pair of the gloves to allow an assessment of fit. These gloves were picked at random,
and which glove was tried on was not noted. There did not appear to be any visual issues with fit
once the gloves were donned. Nor were there any comments around the fit of the gloves and
participants stated the gloves fit as they would expect.
Moisture
To assess the moisture present on the hands during the donning process, MoistSense readings were
taken in three regions. One reading at each of the fingers/thumb tip. Two readings at the top of the
palm, one in the centre and two at the base of the palm. The final set of readings were taken at the
back of the hand. Two were taken below the knuckle, one in the centre and two at the base of the
back of the hand. A diagram of the measurement locations is shown in Figure 5.2. These locations
95
were picked due to their likelihood of contact with the skin as noticed in the previous study. The
donning procedure was conducted as soon as the moisture measurements were taken.
Fingers
Palm
Back of hand
Figure 5.2. Diagram of hands where measurements were taken.
5.3.3 Analysis
The analysis follows as described in Chapter 4. In conjunction with this study, friction measurements
were carried out on three of the participants who took part in the donning study (2 males and 1
female, aged 26-28). As these participants took part in both tests, correlations between measured
friction and donning performance could be examined. These correlations were assessed using
Pearson correlation regression analysis (208). .
5.4 Results
5.4.1 Physical properties
The results obtained from the mechanical testing of the gloves are shown in Table 5.2. This provides
the sample IDs of the gloves used in the following results and discussions, and the measured
parameters, as well as the calculated stiffness (using the equation in Chapter 4, see Equation 4.1).
96
Table 5.2. Results of physical testing of the gloves under EN standards and calculated stiffness.
Where T= thickness, Fb= force at break, Ts= tensile strength, Eb=elongation at break and K= stiffness.
Chlorination
Sample T Fb Ts Eb
Strength K (N/mm)
ID (mm) (N) (MPa) (%)
(ppm)
0.054 6.50 39.90 506.58 0.022
A 500
(±0.003) (±0.49) (±2.88) (±25.69) (±0.003)
0.054 6.93 42.79 511.00 0.030
B 1000
(±0.004) (±0.55) (±3.37) (±16.73) (±0.006)
0.055 6.71 40.96 489.00 0.030
C 2000
(±0.004) (±0.80) (±3.40) (±23.63) (±0.009)
0.059 6.93 38.97 436.00 0.026
D 0
(±0.003) (±0.90) (±4.93) (±39.06) (±0.003)
0.098 16.50 56.00 528.50 0.059
E 500
(±0.003) (±1.12) (±3.64) (±10.88) (±0.003)
0.100 16.30 54.55 502.83 0.059
F 1000
(±0.005) (±1.14) (±3.45 (±16.35) (±0.005)
0.104 17.64 56.78 526.75 0.059
G 2000
(±0.004) (±2.23) (±7.68) (14.67) (±0.005)
0.103 17.23 55.98 523.00 0.055
H 0
(±0.006) (±1.45) (±4.65) (13.82) (±0.004)
± denotes standard deviation
The stress-strain curves obtained from the sample strength testing are shown in Figure 5.3. The
thicker gloves chlorinated at 1000 ppm (F) shows the highest stress at 500% strain, with the thin 500
ppm (A) sample showing the lowest stress at 500% strain. Only one glove sample ruptured before
500% strain, which was the thinner control (D). The average elongation at break of sample C was also
below the 500% strain (489.00 (±23.63) %), however some of the samples did break after the 500%
strain, and the pattern of deviation puts the average before the 500% strain measured. This suggests
the chlorination process has provided the gloves with a greater elastic modulus; however, this is not
observed in the thicker gloves as all the moduli are in the same region. However, sample F does have
a slightly higher modulus than the other thicker glove chlorination strengths and the control.
97
60
50
A
40
Thicker samples
B
Stress (MPa)
C
30
D
E
20
F
Thinner samples G
10
H
0
0 100 200 300 400 500 600
Strain (%)
Figure 5.3. Stress-strain curves of each in-house formed glove. Error bars indicate standard error.
Thickness
ANOVA tests carried out show no significant differences in thickness across the thicker gloves at
different chlorination strengths (F(3, 44)=2.951, p=.059). However, statistically significant differences
in thickness are shown in the thinner gloves (F(3, 44)=5.877, p=.002). Tukey’s (HSD) tests (Table 5.3)
reveal that the differences are present between gloves A, B and C when compared to the control
(p<.05).
Table 5.3. Tukey’s (HSD) test carried out on thinner gloves.
p-Value
Glove sample B C D
Q=0.162 Q=0.243 Q=4.864

A
p=.900 p=.900 p=.007*
Q=0.4053 Q=5.026
p-value B
p=.899 p=.005*
Q=4.621
C
p=.011*
*Denotes statistical significance (p<.05).
98
Tensile strength
No significant differences in tensile strength are present throughout the two sets of glove
thicknesses following ANOVA tests (thin F(3,44)=2.319, p=.089; thick F(3,44)=0.392, p=.760). Thicker
glove samples exhibit greater tensile strength than the thinner samples, which was expected due to
the thickness being double that of the thinner samples.
Force at break
Chlorination does not appear to have affected the break force of the either the thicker or thinner
glove samples, as no significant difference is present between any of the strengths following ANOVA
tests thin (F(3,44)=1.061, p=.375; thick F(3, 44)=1.960, p=.134). As expected, a higher force is
required to break the thicker gloves, when compared to the thinner. Overall, the results show that in
the thicker gloves, glove G (2000ppm) gives the highest force break (17.64 N) amongst the
chlorinated gloves. However, in the thinner samples, glove B (1000ppm) shows to have the highest
break force at 6.93 N (±0.55).
Elongation at break
ANOVA testing shows that the elongation at break is significantly different across both the thinner
(F(3,44)=18.817, p=<.001) and thicker (F(3,44)=14.986, p=<.001) gloves. In the thinner samples, the
chlorination process has shown to significantly increase the elongation at break as all chlorination
strengths (A, B, & C) are significantly higher than the control (D) via the post-hoc Tukey’s (HSD)
testing (Table 5.4). The thicker gloves, however, show differences in the chlorination strengths
following post-hoc testing. Differences are shown to be statistically significant between sample E and
F (Q=6.320, p=.004) as well as E and G (Q=8.153, p=.001). Differences are also present between the
control (H) and the other two chlorinated gloves (F and G).
99
Table 5.4. Tukey’s (HSD) test carried out elongation at break results after ANOVA results for both
thick and thin gloves show significant differences (thin F(3,44)=1.061, p=.375; thick F(3,44)=1.960,
p=.134).
p-value p-value
Thin gloves Thick Gloves
Glove B C D Glove F G H
Q=0.556 Q=2.215 Q=8.892 Q=5.127 Q=8.440 Q=1.099
A E
p=.898 p=.410 p=.001* p=.004* p=.001* p=.085
p- Q=2.772 Q=9.448 Q=3.313 Q=4.029
B F
value p=.220 p=.001* p=.104 p=.031*
Q=6.677 Q=7.341
C G
p=.001* p=.001*
Stiffness
Stiffness is found to be similar in the thicker gloves which are chlorinated (on average 0.059 N/mm),
however more variation is noted in the thinner gloves (Table 5.5). Sample A has a lower stiffness at
0.022 (±0.003) N/mm, whereas B and C have greater stiffness at 0.030 N/mm which leads to
significant differences in the ANOVA test (F(3,44)=4.774, p=.006). Significant differences are noted
between gloves A with B (Q=4.585, p=.012) and C (Q=4.683, p=.010). This is also noted in the thicker
glove samples (F(3,44)=7.887, p=<.001), whereby glove E shows significant differences in stiffness to
glove F (Q=5.731, p=.001) and glove G (Q=5.798, p=.001). Sample A also shows a lower stiffness than
the non-chlorinated control 0.026 (±0.003) N/mm, although this is not significantly different (
(Q=1.578, p=.663).
Table 5.5. Tukey’s (HSD) test carried out on the stiffness of the glove samples after ANOVA results for
both thin (F(3, 44)=4.774, p=.006) and thick (F(3, 44)=7.887, p=<.001) show significant differences.
p-value p-value
Thin gloves Thick Gloves
Glove B C D Glove F G H
Q=4.585 Q=4.683 Q=3.106 Q=5.731 Q=5.798 Q=2.427
A E
p=.012* p=.010* p=.141 p=.001* p=.001* p=.328
p- Q=0.099 Q=1.479 Q=0.067 Q=3.304
B F
value p=.900 p=.702 p=.900 p=.105
Q=1.578 Q=3.371
C G
p=.663 p=.095
100
5.4.2 FTIR
Results of the FTIR spectra are shown in Figure 5.4. Some slight differences exist between the
chlorinated samples. These differences pertain to absorbance only, indicating that there are some
small changes to the frequency of functional groups present on the samples, but ultimately the
samples have similar spectra. The thicker gloves tend to have less absorbance of the functional
groups, but all samples have the same spectral patterns. However, the control samples do have some
noticeable differences to the chlorinated samples. Samples D and H show a major absorbance at
1450cm-1, which shows a much stronger presence of methylene groups (-CH2-). These are present in
the chlorinated samples, but with a much weaker absorbance. At 2512cm-1 there are some peak
absorbances which correspond to S-H (thiol) stretching, in the samples D and H. This peak is not
present in the chlorinated samples. Other notable peaks are present in the controls that are not
present in the chlorinated samples. These peaks arise at 1576cm-1, 871cm-1 and 712cm-1 and
correspond to ketenes (C=C=O), H-C=C bending, and C-H bending, respectively. These groups are
likely to be changed when the chlorine process is conducted. Peaks present in the 2356-2330cm-1
region with samples B, C, G and F correspond to carbon dioxide (209–211). These peaks arise due to
a change in concentration in the air around the FTIR instrument and are not considered to be part of
the results.
Figure 5.4. FTIR spectra of gloves A-H with major functional group differences highlighted and
labelled with corresponding functional groups.
101
5.4.3 Surface roughness
The results show that the surface area roughness (Sa) decreases as the chlorination strength
increases, as shown in Table 5.6. The control samples are found to possess the highest surface
roughness (0.44-0.49µm) whilst the highest strength chlorination (2000ppm) is found to be the
smoothest (0.18µm). Little differences exist between the thinner and thicker gloves, indicating that
the thickness does not affect the surface roughness of the gloves in this study. As both sets of gloves
were produced using the same formers, it was expected that roughness would be similar.
Table 5.6. Results from surface roughness measurements of developed gloves.
Thin Thick
Chlorination
Concentration Surface Surface
(ppm) Image Roughness Image Roughness
(µm) (µm)
0.27 0.22
500
(±0.04) (±0.06)
0.21 0.18
1000
(±0.03) (±0.05)
0.18 0.18
2000
(±0.02) (±0.01)
0.44 0.49
0 (control)
(±0.05) (±0.05)
± indicates standard deviation between Sa of two separate measurements
5.4.4 Contact angle

The results of the contact angles are similar for all the gloves, which have an average contact angle
between 40.0 and 43.4° (Figure 5.5). Similar to the NBR gloves in Chapter 4, there are large overlaps
102
in the standard deviations, which show some variability in the readings. ANOVA shows there are no
statistically significant differences for either the thin (F(3,16)=0.113, p=.986) or thick (F(3,16)=0.425,
p=.738) glove samples, showing the chlorination strength has no effect on the contact angle of the
water.
50
45
40
Contact Angle (°)
35
30
25
20
15
10
5
0
A B C D E F G H
Thin Thick
Glove Sample
Figure 5.5. Average contact angles of gloves with DI water. Error bars indicate standard error.
5.4.5 Donning
Skin moisture
An average of the moisture results for all participants is shown in Figure 5.6. In the dry conditions,
the average moisture between the participants is shown to be 59.23 (±8.85) A.U. for the fingers,
60.55 (±6.70) A.U. for the palm area, and 56.07 (±5.24) A.U. for the back of the hand. After the hands
were wettened from washing, the average moisture between the participants is shown to be higher
at 93.95 (±2.57) A.U. for the fingers, 94.19 (±2.39) A.U. for the palm area, and 85.15 (±4.49) A.U. for
the back of the hand. Wilcoxon signed rank tests were performed between the dry and wet
conditions due to non-normal distribution of the data, as determined by the Shaprio-Wilk test.
Differences in moisture presence are found to be statistically significant between the two conditions
for all the regions tested (p<.05).
103
100
90
80
70
Moisture (A.U.)
60
50 Dry
40
Wet
30
20
10
0
Fingers Palm Back of Hand
Hand area
Figure 5.6. Average skin moisture on the hands in dry and wet conditions. Error bars indicate
standard error.
Donning time
Table 5.7 shows the average time taken to don one glove. There is an increase in the average time
taken to don gloves when the hands had more moisture present, which was also seen in in Chapter 4.
Glove C was the quickest to don when dry, taking 10.31 (±2.98) s on average, whilst glove F took the
longest, taking 16.12 (±4.56) s on average. When the hands were wet, both controls were the
quickest to don, with glove D taking 16.46 (±3.51) s, and glove H taking 18.14 (±3.98) s. Figure 5.7
shows the average time taken for the participants to don one glove in both dry and wet conditions.
As with Chapter 4, analysis was only conducted on the three steps of the process where the glove is
being used (i.e. the ‘pick up’ stage has been removed from analysis).
Table 5.7. Total average time taken to don one glove with pick up time removed.
Time (S)
Glove
Dry Wet
A 13.39 (±2.75) 20.88 (±6.41)
B 11.24 (±2.26) 16.67 (±6.21)
C 10.31 (±2.98) 21.48 (±6.11)
D 12.64 (±1.49) 16.46 (±3.51)
E 16.06 (±6.42) 25.82 (±5.42)
F 16.12 (±4.56) 21.89 (±4.82)
G 11.40 (±3.60) 24.13 (±5.76)
H 12.46 (±3.98) 18.14 (±3.98)
± indicates standard deviation.
104
Preparation Hand Insertion Manipulation
30
25
20
Time (s)
15
10
0
Dry Wet Dry Wet Dry Wet Dry Wet Dry Wet Dry Wet Dry Wet Dry Wet
A B C D E F G H
Thin Thick
Glove Sample
Figure 5.7. Average time taken for each of the three donning steps to be completed for one glove.
Error bars denote standard error across the 6 participants.
Thickness
Statistical analysis results are shown in full in the appendix C1. ANOVA tests across the glove
thicknesses show no statistically significant differences throughout the thin gloves in either condition
(dry F(3,44)=2.464, p=.075 ; wet F(3,44)=1.753, p=.170). However, significant differences are present
across the thick gloves in the wet condition (dry F(3,44)=2.329, p=.087; wet F(3,44)=2.845, p=.048).
Tukey’s (HSD) found significance only between samples E and H (Q=3.902, p=.040). Statistical
analyses were also performed on each step of the donning process. As most of the datasets being
compared were non-parametric, Kruskal-Wallis tests for non-parametric data was used to compare
thin and thick gloves in both the dry and wet conditions. No statistically significant differences were
present between the gloves in the preparation or the manipulation stage of the donning process
(p<.05, Appendix C1.3-C1.5). However, significant differences were found between the thick gloves in
the wet condition during the hand insertion step (H(3, 44)=8.736, p=.019, Appendix C1.4). This is
where most of the differences are observed in the donning process. The hand insertion step was
105
then subjected to a post-hoc Dunn’s test for non-parametric data, which shows statistically
significant differences between the gloves in E and H (Z=2.878 p=.002).
Gloves were also checked for statistical significance at each chlorination strength between
the thick and thin gloves. Paired t-tests show no statistically significant differences between thin and
thick gloves at each chlorination, except for 1000ppm chlorination when gloves are donned in the dry
condition (t(11)=-2.823, p=.008). The smallest difference is observed with the control gloves (D and
H), which differ by 0.14 seconds on average between thickness in the dry condition. The largest
difference observed is with the 500ppm gloves in the wet condition, which differ by 4.94 s, on
average.
Hand condition comparison
Significant differences were found between donning times in the dry and wet conditions with each of
the gloves, with the exception of glove sample F (p>.05). Results from the t-tests are shown in Table
5.8. In the preparation and manipulation stages, no statistically significant differences were found for
any of the samples (p>.05). In the hand-insertion phase, however, statistically significant differences
were found for all glove samples (p<.05).
Table 5.8. Results of paired t-tests between gloves in dry and wet conditions at each stage of the
donning process.
p-value
Glove Sample
Total Time Preparation Hand Insertion Manipulation
T(11)=3.447 W=18 T(11)=-3.313 W=19
A
p=.001* p=.122Δ p=.002* p=.158Δ
T(11)=-2.976 T(11)=0.672 T(11)=-3.047 T(11)=-1.269
B
p=.008* p=.552 p=.002* p=.145
T(11)=-4.887 T(11)=0.467 T(11)=-4.392 W=25
C
p=.013* p=.580 p=.001* p=.159Δ
W=12 T(11)=1.121 W=3 W=13
D
p=.016Δ p=.255 p=.005 Δ p=.502Δ
T(11)=-3.461 T(11)=-0.579 T(11)=-3.116 T(11)=-1.928
E
p=.006* p=.588 p=.005* p=.125
W=14 W=22 W=12 W=32
F Δ Δ Δ
p=.075 p=.177 p=.047* p=.464Δ
T(11)=-4.826 T(11)=-0.755 T(11)=-5.089 W=37
G
p=.001* p=.521 p=.003* p=.107Δ
T(11)=-2.892 T(11)=-1.943 T(11)=-3.332 W=30
H
p=.010* p=.828 p=.005* p=.381Δ
*Denotes statistical significance (p<.05). Δ Denotes Wilcoxon Signed Rank Tests carried out due to
either one or both datasets being non-parametric
106
5.4.6 Physical parameters to donning time
Measured physical parameters to donning time
It is important to establish if the physical properties, tested by the industries, have correlations to the
performance, as this will allow manufacturers to quickly assess the implication different parameters
may have on donning. Table 5.9 shows the correlation coefficients (r) and statistical analysis obtained
from the regression analysis for both the total donning time, and the hand insertion step. The r can
range from 1 and -1. A value of 0 shows no association between the two variables. Correlation
coefficients between 0.3 and 0.5 are viewed as weak positive correlations, whereas above this (0.5-1)
are seen as moderate-stronger positive correlations. (212, 213). The hand insertion step has also
been included as this is the step where the hand has more interaction with the glove overall.
Stronger correlations can be seen in the wet conditions, rather than the dry. The thickness of the
gloves shows a moderate correlation to the time taken to don the gloves, which is stronger in the
wet condition in the hand insertion step (r=.557; p=.152). However, it is shown that the thickness is
similar throughout the gloves in each set. While the donning times are not too dissimilar between
glove sets, this correlation is stating that the thicker the glove, the longer the glove takes to put on.
The elongation at break of the gloves shows moderate correlation to both the total donning time and
the hand insertion step, but only in the wet condition. Moderate correlations observed with the
force at break have similar correlation coefficients to the thickness parameter, with more correlation
being observed in the wet condition. Surface roughness shows moderate correlations to both the
total donning time and the hand insertion step in the wet condition only (r=-.655 and r=-.589,
respectively). This indicates that, as the surface roughness decreases, the donning time increases.
However, this is not statistically significant in any of the conditions (p>.05, Table 5.9). Tensile
strength shows to have moderate correlations to the total donning and hand insertion step. In the
wet condition, these are statistically significant (p<.05, Table 5.9). This strongly indicates that in the
wet conditions, the higher the tensile strength of the glove, the longer it takes to don (Figures 5.8
and 5.9).
107
Table 5.9. Pearson correlation coefficient results for total donning time and the hand insertion step
against the physical parameters, where r is the Pearson correlation coefficient, and p is the statistical
significance.
Total donning time to tested parameter

Force at
Surface Roughness Strength Thickness Elongation
Break
r p r p r p r p r p
◊ Δ Δ
Dry -.065 .878 .511 .196 .476 .233 .171 .686 .460 .247
Wet -.655◊ .078 .726◊
.041* .510 ◊
.197 .599◊ .117 .534 ◊
.173
‘Hand Insertion’ step time to parameter
Force at
Surface Roughness Tensile Strength Thickness Elongation
Break
r p r p r p r p r p
◊ ◊ ◊
Dry -.206 .626 .638 .089 .545 .162 .257 .539 .540 .167
◊ ◊ ◊ ◊ ◊
Wet -.589 .124 .770 .025* .557 .152 .627 .096 .583 .129
Δ
Denotes a weak correlation. ◊Denotes a moderate correlation. *Denotes statistical significance
60 G
F E
50 H
Tensile Strength (MPa)
B R² = 0.5275
C
40
D A
30
20
10
0
0 5 10 15 20 25 30
Total donning time (s)
Figure 5.8. Correlation of tensile strength to the total donning time of the gloves in the wet
condition. Thin gloves are indicated by blue, and thick gloves by red.
108
60 G
F E
50 H
Tensile Strength (MPa) B R² = 0.5937
C
40
D A
30
20
10
0
0 5 10 15 20 25
Time taken for hand insertion step (s)
Figure 5.9. Correlation tensile strength to the ‘hand insertion’ step time of the gloves in the wet
condition. Thinner gloves are indicated by blue, and thick gloves by red.
Stiffness and donning time
Stiffness of the material is thought to be an important characteristic when assessing these gloves.
Firstly, the stiffness was compared to the physical parameters, to assess if there were any
correlations between the measured parameters and the calculated stiffness. Of the parameters, only
tensile strength was found to have strong correlations with the calculated stiffness, as shown in
Table 5.10. The results shown strong correlations with the measured stiffness at 100, 300 and 500 %
strain (p<.05). As a greater stiffness is noted in the thicker samples, the results appear as two
clusters, as in Figure 5.10.
Table 5.10. Pearson correlation coefficient results comparing the stress at 100% strain and the tensile
strength of the samples, where r is the Pearson correlation coefficient, and p is the statistical
significance.
Correlation of tensile strength to stress at % strain

100 300 500
r .976¤ .901¤ .991¤
p <.001* .002* <.001*
¤ Denotes a strong correlation. * Denotes statistical significance
109
70
H G
60
E
Tensile strength (MPa)

50 B
F
A
40 R² = 0.9528
C
D
30
20
10
0
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07
Stiffness at 100% strain
Figure 5.10. Correlation of tensile strength to stress at 100% strain. Thinner gloves are indicated by
blue, and thick gloves by red.
As 100% strain is much more likely in the glove donning process, correlations have been drawn
against the stiffness at this point, and the time taken to don the gloves. Furthermore, the glove
stiffness has also been compared to each of the stages of the donning process, which is shown in
Table 5.11. The results show correlations between the steps in the dry hand condition; however,
correlations are only found in the total donning time and the hand insertion step with the wet hand
condition. Additionally, a statistically significant negative correlation is shown in the preparation
stage in the dry condition (r=-.908; p=.002). This strongly indicates that the stiffer the glove sample,
the quicker participants completed the preparation step (Figure 5.11). However, overall, a moderate
correlation is drawn between the total time to don the gloves in the wet condition (r=.503; p=.204),
compared to the dry condition which shows a weaker moderate correlation (r=.420; p=.300).
Table 5.11. Correlation of donning time to stiffness of each of the samples at 100% strain at the total
donning time and each of the three stages of the donning process.
Stiffness @100% strain

Total Preparation Hand Insertion Manipulation
r p r p r p r p
Dry .420 Δ .300 -.908¤ .002* .510◊ .197 .419 Δ .301
Wet .503◊ .204 .221 .599 .535◊ .172 .069 .871
Δ
Denotes a weak correlation. ◊ Denotes a moderate correlation. ¤ Denotes a strong correlation. *
Denotes statistical significance (p<.05).
110
3.0 D
A
B R² = 0.8245
2.5
Preperation time (s) C

2.0 H G
1.5 E F
1.0
0.5
0.0
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07
Material stiffness (N/mm)
Figure 5.11. Correlation of stiffness at 100% strain with the preparation stage of the donning process
in the dry condition. Thinner gloves are indicated by blue, and thick gloves by red.
5.4.7 Friction
Moisture
The results obtained from the moisture measurements for the friction tests are shown in Figures 5.12
a-c. In the donning test, the average results had moisture levels of 59.23 A.U. on average for the dry
and 93.95 A.U. on average for the wet condition. The participants for the friction moisture show
results similar donning moisture results. Paired t-tests between dry and wet conditions show the
moisture content is statistically significant for each participant in each glove condition (p<.001).
100 100
90 90
80 80
70 70
Moisture (A.U.)
Moisture (A.U.)
60 60
50 50
Dry Dry
40 40
30 Wet Wet
30
20 20
10 10
0 0
A B C D E F G H A B C D E F G H
Glove Glove
111
c) Participant 3
100
90
80
Moisture (A.U.)
70
60
50
40 Dry
30 Wet
20
10
0
A B C D E F G H
Glove
Figure 5.12 a-c. Results of moisture measurements for each participant in each glove test. Error bars denote
standard error.
Glove-skin behaviour
The glove-skin behaviour was assessed in the first assessment of the friction, where the glove sample
was attached to the force plate around the edges only, leaving the centre free to undertake relative
movement. Many of the results obtained followed a typical friction graph, as seen in Chapter 4 (see
Section 4.3.5). However, via this method, stick-slip and some sample stiffness contributed to the
friction measurements. There are overall differences in the way the NBR reacts to the friction in both
sets of thicknesses, and when moisture is added. This was mostly noticeable in the medium and high
loads. Figures 5.13 and 5.14 show an example of the friction behaviour with one participant at 1 N
with glove A (500ppm) and D (control) in the thinner gloves. In the chlorinated samples, the dry
condition shows some ‘snapping’ of the NBR. The ‘snapping’ is defined as the glove being pulled with
the finger, and then ‘snapping’ back into place, as shown in Figure 5.15. In the control, it can be seen
that this snapping behaviour is more frequent, and in some participants, stick-slip also occurs. With
the addition of water, the ‘snapping’ action worsens in these chlorinated samples, which can be seen
from the friction graph on the right of Figure 5.14. When moisture is added in the unchlorinated
sample, there are many more incidences of the snapping in combination with stick-slip. As observed,
the finger would drag some of the glove, and when it snaps back, stick-slip would then occur, and
then some of the glove would be pulled with the finger again. However, in the thicker samples, a
slightly different behaviour is observed. In the dry condition, the gloves exhibit some of this snapping
action, in combination with stick-slip (Figure 5.16). When moisture is added, there is more
pronounced stick-slip with little of the ‘snapping’ action observed. No major differences are observed
in the behaviour between the control and the chlorinated samples in the thicker gloves.
112
Normal Force Horizontal Force
3 Dry Wet
2.5
2
Force (N)
1.5
1
0.5 Snapping
0
0 2 4 6 8 10 12 14 16
Time (s)
Figure 5.13. Friction graphs obtained from glove A (500ppm) in dry and wet conditions at the 1 N
target load.

4
Dry Wet
3.5
3
2.5
Force (N)
2
1.5
1
0.5
0
0 2 4 6 8 10 12 14 16 18 20
Time (s)
Figure 5.14. Friction graphs obtained from the thin control sample (D) in dry and wet conditions at
the 1 N target load.
113
glove pulled with the finger
glove ‘snapping’ back

Figure 5.15. Glove stretching with finger and ‘snapping’ back.
5
Dry Wet
4
Force (N)
0
0 2 4 6 8 10 12 14 16 18
Time (s)
Figure 5.16. Friction graphs obtained from glove sample E (500ppm) in dry and wet conditions at the
1 N target load.
As the snapping action was occurring, this means there was relative motion of the glove across the
force plate, thus CoFs calculated may not be an accurate measure of the skin-glove interaction, but
rather the glove-force plate friction. Therefore, the experiment was repeated, with the glove section
fully secured (with double-sided tape) to the force plate to prevent movement, as in Chapter 4.
Friction Coefficients
Where discussed, friction coefficients obtained for each participant are shown in the appendix (C2)
with complete statistical analysis (C3-C5).
114
Thin gloves
The average friction and CoFs at each normal load in the thinner gloves are shown in Figures 5.17 (a-
f). In most of the participants, with all gloves, the CoF decreases as the load increases between the
maximum and minimum target load. However, friction does increase with increasing target load.
When moisture is introduced, the friction increases throughout the samples, in most instances.
However, there are some exceptions to this, for example participant 3 at a target load of 0.1 N
produces a dry CoF of 4.78 (±0.08) and a wet CoF of 4.02 (±0.01). Statistically significant differences
are shown across all loads between the dry and wet conditions (p<.05). However, participants 2 and
3 show no significant differences in friction between wet and dry conditions in gloves A and D at the
minimum load (p<.05). In the wet condition, glove D shows the highest friction at the minimum load
with participants 1 and 2. Glove A (wet) shows a greater friction coefficient at the minimum load with
participant 2. There is a slight trend that can be followed with the friction decreasing as chlorination
strength is increased in the dry condition for participants 2 and 3. Overall, the control sample (D) has
a greater friction coefficient, followed by glove A. Then B and C tend to have similar friction
coefficients throughout the participants, with glove B generally lower than C, except in participant 3.
No statistical difference is shown between B-C friction at the low and mid load in participants 1 and
2, following ANOVA and post-hoc Tukey’s (HSD) tests (p<.05). The full statistical analysis (appendix
C3-C4) shows that the most differences are highlighted between the D and gloves B and C at all loads
in all conditions.
115
5 7
A dry 6 A dry
4
A wet A wet
5
Frictional Force (N)
B dry B dry
3
4 B wet
B wet
CoF
C dry 3 C dry
2
C wet
C wet 2
D dry
1 D dry
1 D wet
D wet
0 0
0.0 0.3 0.6 1.0 1.3 0.0 0.3 0.6 1.0 1.3
Load (N) Load (N)
5 7
A dry 6
4 A wet A dry
5
A wet
Friction Force (N)
B dry
3 4 B dry
B wet
CoF
B wet
C dry 3
2 C dry
C wet 2 C wet
1 D dry D dry
1
D wet D wet
0 0
0.0 0.3 0.6 1.0 1.3 0.0 0.3 0.6 1.0 1.3
Load (N) Load (N)
5 7
A dry
6 A dry
4 A wet
5 A wet
Friction Force (N)
B dry
3 B dry
B wet 4
B wet
CoF
2 C dry 3 C dry
C wet C wet
2
1 D dry
D dry
1 D wet
D wet
0 0
0.0 0.3 0.6 1.0 1.3 0.0 0.3 0.6 1.0 1.3
Load (N) Load (N)
Figures 5.17 a-f. Average friction results from participants 1-3 with the thinner glove samples. Error
bars denote standard deviation.
116
Thick gloves
The average friction and CoFs at each normal load in the thicker gloves are shown in Figures 5.18 (a-
f). Friction increases with the increasing target load. As with the thinner gloves, when moisture is
added, there is an increase in friction. Differences between dry and wet CoFs are shown to be
significantly different (p<.05, appendix C3-C5). However, glove H in participant 3 shows no significant
difference between the wet and dry conditions at the minimum (dry µ=1.22; wet µ=1.29; t(2)=0.356,
p=.756) and maximum (dry µ=2.08 ; wet µ= 2.04; t(2)=3.683, p=.066) loads. Glove H is shown to have
the lowest CoF when compared to the chlorinated gloves, followed closely by glove G at the medium
and high loads. However, many of the loads show statistical differences between G and H across the
participants (p<.05). When wet, there is little pattern in the results, as the gloves show different
friction coefficients with the participants. As with the thinner samples, significant differences are
shown frequently between the chlorinated gloves and the control sample (p<.05). In conjunction
with this gloves F and G show frequent statistical differences from glove E (p<.05), but less frequent
differences with each other (p>.05). Overall, across the participants, glove G, when the finger is dry,
produces the lowest CoFs across the target loads. In the wet conditions, glove G gloves lower friction
in participants 1 and 2, followed closely by glove F, which shows to produce lower friction with
participant 3.
117
4 8
E dry 7 E dry
3 E wet 6 E wet
Friction Force (N)
F dry 5 F dry
F wet
CoF
2 4 F wet
G dry 3 G wet
1 G wet 2 G wet
H dry 1 H dry
0 H wet 0 H wet
0.0 0.3 0.6 1.0 1.3 0.0 0.3 0.6 1.0 1.3
Load (N) Load (N)
4 8
E dry 7 A dry
3 E wet 6 A wet
Friction Force (N)
F dry 5 B dry
CoF
2 F wet 4 B wet
G dry 3 C dry
1 G wet 2 C wet
H dry 1 D dry
0 H wet 0 D wet
0.0 0.3 0.6 1.0 1.3 0.0 0.3 0.6 1.0 1.3
Load (N) Load (N)
4 8
E Dry
7 E dry
E Wet
3 6 E wet
Friction Force (N)
F Dry
5 F dry
F Wet
CoF
2 4 F wet
G Dry
3 G dry
G Wet
1 2 G wet
H Dry
1 H dry
H Wet
0 0 H wet
0.0 0.3 0.6 1.0 1.3 0.0 0.3 0.6 1.0 1.3
Load (N) Load (N)
Figures 5.18 a-f. Average friction and CoF from participants 1-3 with the thicker glove samples. Error
bars denote standard deviation.
118
Thickness differences
Paired t-tests show significant differences between thicknesses at the different loads. Participant one
shows most of these differences, as each of the target loads produces a statistically different (p<.05)
CoF between the thick and thin gloves. In general, the friction in the thicker gloves is slightly higher
than those in the thinner gloves, with the exception of the control, which is significantly lower in the
thicker gloves. In the thin gloves, the friction of the control (D) tends to be a higher friction at each
load (in two out of the three participants), whereas in the thicker gloves, the friction for the control
(H) is generally the lower. This difference in behaviour is highlighted in the t-tests, which show the
majority of differences between gloves D and H being statistically significant (p<.05, appendix C3-C5).
In both thickness sets the 2000 ppm (C and G) gloves show to produce the lowest CoF in the dry
condition. However, when wet, the 1000 ppm (B and F) produces a the lowest CoFs. The thicker
samples also showed stick-slip behaviour in some participants at the med/higher loads when
moisture was added.
5.4.8 Friction correlation to donning
Both of the donning tests have shown that most variation is present in the ‘hand insertion step’, and
this is where more friction occurs. Thus, this step has been explored in conjunction with the total
donning time for each of the three participants taking part in the friction tests. Tables 5.12-5.14 show
the Pearson correlation coefficients for each participant. The results show mostly moderate
correlations between CoF and time taken in the wet condition. Much of this correlation is noted in
the hand insertion step. However the stronger correlations are present in the total donning time.
Participant 1 shows a moderate correlation in the wet condition to the time spend in the hand
insertion step at the maximum load (r=.621, p=.101). On the other hand, the stronger correlations in
participant 2 (Table 5.13) and 3 (Table 5.14) are noted in the total donning time. The strongest
correlation coefficient for participant 2 is present at the minimum force (r=.682, p=.063), whereas
the strongest for participant 3 is noted in the maximum force (r=.699, p=.054). None of the
correlations had any statistical significance across the participants (p>.05). There is little in the way of
pattern of behaviour in the correlation. However, it should be noted that glove E has a consistently
high CoF with all participants and took the longer to don with participants 1 and 2.
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Table 5.12. Correlation of CoF to total donning time and hand insertion step in participant 1.
Min load (0.1 N) Med load (0.5 N) Max load (1 N)

Donning step Condition
r p r p r p
Dry .532◊ .175 .115 .787 .070 .870
Total
Wet .253 .546 -.141 .740 .568◊ .142
Δ
Dry .498 .209 .145 .732 .075 .859
Hand insertion Δ ◊
Wet .349 .397 .117 .783 .621 .101
Δ
Denotes a weak correlation. ◊ Denotes a moderate correlation.
Table 5.13. Correlation of CoF to total donning time and hand insertion step in participant 2
Donning step Condition Min load (0.1 N) Med load (0.5 N) Max load (1 N)
r p r p r p
Total Dry .296 .477 .079 .853 -.115 .786
Wet .682◊ .063 .444Δ .271 -.108 .799
Hand insertion Dry .160 .704 -.117 .828 -.294 .480
◊ Δ
Wet .630 .824 .434 .282 -.109 .799
Δ
Denotes a weak correlation. ◊ Denotes a moderate correlation.
Table 5.14. Correlation of CoF to total donning time and hand insertion step in participant 3
Donning step Condition Min load (0.1 N) Med load (0.5 N) Max load (1 N)
r p r p r p
◊ ◊
Total Dry .143 .736 .638 .088 .699 .054
Wet .526◊ .180 -.216 .607 .127 .764
Δ ◊
Hand insertion Dry .072 .865 .455 .257 .698 .054
Wet .627◊ .096 -.221 .601 .069 .871
Δ ◊
Denotes a weak correlation. Denotes a moderate correlation.
5.5 Discussion
The results of the physical properties suggest that, in the thinner gloves, chlorination may have
impacted the thickness, making the glove slightly thinner as the concentration of chlorine increases.
The aim of the chlorination process is to chemically change the surface of the gloves, in order to
improve the donning process and reduce tack (16, 198). These chemical changes may be the reason
for the slight reduction in thickness. However, due to an incredibly small difference (±0.005mm), it is
likely that this is a random result. Another difference is highlighted in the elongation at break of the
different samples. In the thick gloves, the 500ppm sample has similar elongation at break to that of
the control, which is statistically different from the 1000-2000ppm chlorination strengths. However,
the results are similar, having no large differences in the elongation, with standard deviations
overlapping. Thus, the differences may have some statistical significance, but the results are too
similar to conclude that this is anything more than random, as statistical difference may have arisen
120
as a result of the variation in the data, rather than any overall difference. Further work would have to
be conducted to reveal any differences if present. The aim of this study was to compare gloves with
the same manufacturing process and chemical constituents, with the exception of the treatment
method, which has been achieved by the virtue of these physical property results.
Comparison of developed samples to industry
It is noted that there is some discrepancy between this data, and what is normally found within
industry. When gloves are chlorinated, the polymers vulcanise and cross link (14, 38, 214). This
lowers the tensile strength, elongation, force at break and modulus of the gloves. In effect, the
chlorination process is detrimental to the gloves, decreasing their shelf life. However, in the gloves
manufactured in this study, the detriment is not greatly reflected. In many cases, there is little
difference in the physical properties when comparing the chlorinated gloves to the control sample. In
the elongation at break, the control sample is shown to be significantly lower in the thinner gloves.
The difference in the results here, in comparison to what is shown in the industry, may be down to
the small-scale production. Gloves were dipped in batches for this study, whereas in manufacturing
plants they are continuously on-line producing gloves, with hundreds of formers (14, 38, 51). This is
all done successively, from the moment the former is dipped into the coagulant it follows a linear,
timed process. However, in this small-scale production, the batches were dipped (two gloves at a
time) and then left whilst other gloves were dipped. It is possible that the small-scale, room
temperature/humidity and time left between dipping could have affected the properties of the
gloves. It could also be that the chlorination method and time of chlorine exposure has contributed
to the differences (16, 51, 52, 214). However it has been previously discussed by Karunaratne (51),
that the chlorination method should not affect the process, as they all work in a similar way. It must
also be noted, that more variation (standard deviation) is observed in the control samples in the
thinner gloves. In the thicker gloves the sample with the highest physical properties is the control
sample. Therefore, it is likely that the properties were affected by the chlorination as expected, but
not as significantly as seen in the industry (16, 51).
The control sample is proven to be unexposed to the chlorination process via the results of
the FTIR. The IR spectra shows that the control samples in this study have not been fully cured. The
peak around 900cm-1 shows the H-C=C bending, which is not present in the chlorinated samples. In
addition the thiol peak (H-S-H) is present in the control at ~2500 cm-1 (210, 215). These peaks
strongly indicate that the vulcanisation is incomplete, and there are no sulphur cross links present.
Without sufficient vulcanisation, the glove film tends to be softer. Consequently, the controls should
have superior physical properties, which is observed in many of the physical properties. However,
121
Tohsan, Joomcom, and Limphira (216) does show that the tensile strength of NRL gloves tends to
decrease when the vulcanisation time is longer than 10 minutes due to the disulphide and
polysulphide links created during the vulcanisation process. Therefore, it does seem there is some
discrepancy between the processes used when manufacturing gloves on a small scale such as this,
and a larger scale in industry, which slightly affects the properties of the end products.
5.5.2 Donning and friction

Size
All participants had stated they wear medium gloves as their ‘best fit’ size, hence their recruitment
for this study as only medium sized gloves were manufactured. However, according to the HSE (149)
chart for glove sizing, it was found that 2 participants were recommended to wear large while 3 were
medium and 1 was small. There did not appear to be any visual issues with fit once the gloves were
donned. Nor were there any comments around the fit of the gloves.
Chlorination Strength
The results of the donning process do not show statistically significant differences between the
various glove chlorination strengths in the dry conditions. It was presumed that the controls (D and
H) would take longer to don due to the increased friction from the ‘tacky’ surface, originating from
the manufacturing process. However, this does not appear to be the case, which is likely to be a
result of the powder being present. In both thicknesses, the 2000ppm (C, G) chlorination was quicker
to don in the dry conditions, but the non-chlorinated gloves were quicker in the wet conditions. Only
one significant difference was found to be present, which was between 500ppm concentration and
the control in the thicker gloves when the hands were wet. As the control was faster to don, this
suggests that chlorinating to 500ppm has an adverse effect on the donning process.
When correlating the donning to the friction, much of the correlations are present in the wet
conditions, rather than dry, presumably due to similar incidences of the glove sticking to the skin
across the participants. There is slight evidence that chlorinating to 2000ppm does improve the
frictional properties and donnability of the glove in the thinner samples. For all participants glove C
tends to be closer to the bottom of the correlation trendline (low friction and low donning time).
However, the frictional properties of the thicker sample (G) were found to have a greater CoF and
took longer to don. This would make it appear that there is some ‘optimum’ friction to aid the
donning process, around the 1000-2000ppm region. Knowing the region of strength for optimal
friction can be salient for manufacturers to improve glove user compatibility. However, the material
parameters must be factored into the donning process. The difference in donning ability between the
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two gloves (C and G) is most likely to do with the difference in the physical properties of the two
glove thicknesses and behaviour of the samples when donning.
Thickness
The thickness of the glove does appear to have affected the donning time, with the thicker gloves
taking longer on average to don than the thinner gloves. Significant differences were observed
between samples with the 1000ppm (B-F) chlorination strength (p=.008). This indicates that
1000ppm is the only chlorination strength at which gloves affect donning between the thicker and
thinner gloves. This strength of chlorination is also shown to have the ‘optimum’ friction in the
thinner gloves. This could be due to it being the minimum concentration to needed to reduce the
anti-tack properties of the manufacturing process. The lack of statistical difference in the other
results is likely to be due to the physical properties, and how these properties affected each step of
the donning process. Firstly, participants spent less time on average in the ‘preparation’ stage with
the thicker gloves. This is likely to due to the glove stiffness. The thicker gloves were shown to be
stiffer than the thinner gloves. Therefore, these gloves were less likely to be subjected to creasing
and folding when in the packaging, as shown in Figure 5.19. This means they did not require as much
opening and mechanical separating as the thinner gloves. Furthermore, the ergonomics of easily
gripping the cuff of the thicker samples is likely to be more streamlined, as the thinner gloves may be
harder to grasp given less material being present. A possible way to circumvent these problems, is to
make the cuff of the thinner gloves thicker, and therefore easier to grab. However, this will not solve
the problem of the gloves being more creased due to packaging, which will cause issues with opening
up the glove as well as sliding the fingers in, as discussed in Chapter 4, where the fingers experienced
more sticking at the top of the palm and the base of the fingers.
1 2
Figure 5.19. 1) thicker glove (F); 2) thinner glove (B)
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Secondly, the ‘manipulation’ of the gloves also differed between glove thicknesses. Where the
thicker glove was donned, the rolling of the glove restricted the hand from being fully inserted and
more time was added to unroll the glove. This was a by-product of the hand insertion step, where
the glove moved easier down the fingers/hand in the thicker gloves but induced more rolling. In the
thinner gloves, the glove was found to stick more to the fingers and participants spent time pulling at
the fingers and pushing down at the top of the palm/joints of the fingers to ensure the glove fit, all of
which was also noted in the previous work (Chapter 4).
The first friction test conducted, looking at the behaviour of the different samples, confirms
there are differences in the way both the thick and thin glove sets react to the normal load.
Furthermore, the correlation of mechanical parameters indicates that the stiffness of the material is
an intrinsic part in the donning procedure. In the dry conditions, the thinner gloves exhibit more
‘snapping’, which is problematic when donning. It would appear, even though the skin is dry, there is
some adhesion and/or the stiffness of the sample is allowing conformation and bending of the glove
around the skin. When donning the gloves, this is likely to incur more incidences of sticking as the
glove bends around the fingers, previously discussed in Chapter 4. This is much more problematic in
the control gloves (D), in which stick-slip is then introduced. It is important to remember that glove D
and H will have contained some powder residue from the manufacturing/former releasing process. It
is possible that the powder may have been more present on the thicker gloves. However, the gloves
were of a similar roughness (0.44µm and 0.49µm respectively). Thus, it is expected that the powder
held onto the surface, however minimal, would be similar. Due to the similarity and frequency of the
issues in the donning, there is little difference in the overall time taken to don the gloves of different
thicknesses. Some participants commented that when donning the thicker gloves, the rolling had
restricted their movement to the point that it caused some pain. This was noted only after they had
donned the gloves and was not a level of pain where the participants did not wish to continue the
study. This was noted more in the two participants who had a recommended fit of ‘large’ by the HSE
(149).
Moisture
Across the total time taken to complete the three steps, wet hands were shown to significantly
increase the time taken to don the gloves (p<.05). The only exception to this was glove F. Although,
the wet hand condition took on average 5.77 seconds longer to don than the dry condition, no
significance was found. Most variation is noted in the hand insertion step, which is to be expected as
this is where most of the friction occurs between the glove and the skin. These findings were also
touched upon in Chapter 4. In the thicker gloves, there is a visually smoother transition as the fingers
124
slide down the gloves in the dry condition. However, when moisture is added, this step is slower,
indicating stick-slip behaviour between the skin and the glove, which was confirmed in the friction
results. The thinner gloves had a tendency to stick more to the hand, causing many issues whereby
the participants had to pull harder on the glove and/or pull the glove away from the skin where the
glove had stuck. Gloves C and G (2000ppm) had to have the greatest difference between the dry and
wet conditions, increasing by 11.17 and 12.73 seconds respectively when moisture was present. This
indicated that 2000ppm is more detrimental to the donning process when moisture is present.
However, when dry, this appears to offer optimal friction and a quicker overall donning time. As the
chlorination strength increases, the roughness of the surface decreases. In the dry condition this
appears to aid the friction, but not necessarily the donning process, which is likely to be down to
physical behaviour of the glove samples, as discussed. However, the smoother surface in the wet
condition can cause more contact through capillary action and contact area, as discussed in Chapter
4 (see Section 4.6.1). Whilst it is clear that moisture adversely affects the donnability of the gloves,
there is no clear indication that there is a strength of chlorination which aids or exacerbates this
issue.
Surface roughness
The correlation of surface roughness to donning time suggests that the rougher the surface, the
quicker the glove was to don. This is due to the rougher surfaces of the unchlorinated gloves D and H,
pulling the trendline up, and indicating a greater correlation. The rougher surface could increase
friction due to the gaps being filled by finger ridges as the surfaces move over each other (rough-
rough contact), increasing asperity contact through an increase in surface area contact. Furthermore,
when moisture is present, the water will flood these asperities, and cause capillary adhesion to the
gloves. When the surface is smoother, as in the case of the 2000 ppm chlorinated samples, there
appears to be a decrease the skin friction when compared to the 1000ppm samples. At 500-
1000ppm, the smoother, but rougher than 2000ppm, surface is a little more detrimental, as
evidenced through increased CoFs. This is due to several factors, but mostly the stiffness and
behaviour of the samples under load, which leads to different skin-glove interactions.
5.5.3 Physical parameters

The elongation at break parameter has a weak correlation to donning when the hands are wet. This
is likely suggesting that the less stiff the sample is (the more elongated it can ger), the more likely the
glove is to conform to the fingers, causing issues with the glove adhesion to the skin when moisture
is present. In conjunction with this, there is a weak correlation of the donning time to tensile
strength. There is a statistically strong correlation between the sample stiffness and the tensile
125
strength of the gloves observed in this study. This indicates that these properties are dependent
upon each other, however more samples should be studied to conclude this. If this is a true
correlation, this may allow for manufacturers to determine the donning capability and/or behaviour
by assessing the tensile strength, as the tensile strength shows some correlations to the donning
time, and stiffness also indicates correlation to the preparation stage. The correlations suggest that
the stronger/stiffer the glove, the longer the glove takes to put on. Gloves chlorinated to 500ppm (A,
E) and the thicker 2000ppm (C, G) have the highest tensile strengths, and highest hand insertion
times, with respect to their thickness. The unchlorinated gloves (D, H) show the lowest tensile
strength (for their respective thicknesses), and take the least time spent in the hand insertion step.
This suggests that when the gloves are chlorinated to 1000ppm, the tensile properties formed in this
glove allow for an easier donning process, as the hands spend less time in the ‘hand insertion’ step of
the donning process. However, the 2000ppm glove is proven quicker to don overall, and has the
lowest friction coefficients in the thinner gloves, further indicating the optimum chlorination strength
is between 1000-2000ppm.
5.6 Conclusions
A summary of the findings from this chapter are shown in Table 5.15. The table shows the results of
which gloves were quicker to don and compares the results of donning and friction with the wet
hand condition to the dry condition. In all of the tests, the wet hand was shown to complicate the
process and increase the time taken to don the gloves and increase friction.
Table 5.15. Findings of the chapter comparing the outcome of performance of the wet hand to the
dry hand condition with comments on the quickest glove to don.
Chlorination Strength (ppm)

Measured
0 500 1000 2000
parameter
Donning Quickest to don Greatest friction of Quickest to don Quickest to don
performance when thicker chlorinated gloves when wet when dry
Thin gloves (A-D)
Donning Time Increases Increases Increases Increases
Friction Increases Increases Increases Increases
Thick gloves (E-H)
Donning Time Increases Increases Increases Increases
Friction Increases Increases Increases Increases
126
• Together with Chapter 4, a methodology has been designed to identify the complications of
donning, and assess the ease of donning of gloves, as they are being donned in their natural
state. This has allowed identification of how differences in gloves affect the donning process.
The results of this protocol highlight four key stages of the process. Most variation and
complication in this process is highlighted at the hand insertion step of donning a glove where
the hand-glove system is more complex.
• Inclusion of moisture increases friction in all gloves, as seen with the previous study in Chapter
4. This is the same for all chlorination strengths, and the controls used in this study, showing
no chlorination strength lessens the complexity of donning gloves with wet hands.
• When donning gloves it is clear that the skin-material friction is salient, which is dependent on
the degree of chlorination, and the thickness of the material. In the thinner gloves, the
chlorination is shown to aid the donning process through a decrease in surface roughness and
friction. This decrease in friction is shown to be beneficial to donning in previous studies (57,
137). The thicker gloves, however, show a lower friction coefficient in the control, and the
gloves were quicker to don. When chlorinating gloves, concentrations between 1000 and
2000ppm appear to be optimal, with a lower friction coefficient and quicker donning times
observed in the dry conditions. Assessing chlorination strengths in between the 1000 and 2000
ppm may reveal a more optimum chlorination required for reducing friction with both dry and
wet hands. However, the control gloves are easier to don than the chlorinated materials, with
the thicker of the gloves showing a lower friction coefficient. This is likely to be due to the
presence of powder, reducing the friction more than the chlorination.
• The bulk physical properties of the gloves should be accounted for when assessing the ease of
donning gloves, not just the friction. Correlations have been shown between the stiffness of
the material and the donnability. The internal coating/treatment is only discussed in previous
literature. However, this study shows the complexity of the donning process requires a lot
more consideration.
• Elongation at break and tensile strength are highlighted to be two of the mechanical
parameters which require consideration during the manufacturing process. In particular,
tensile strength shows statistically significant correlations to the material stiffness, which in
turn shows correlations to the donning process at the preparation step. It is proposed that the
stiffer glove samples bend and fold less in the packaging, which makes it easier to separate the
two layers, and grab the cuffs to don the gloves. Material manufacturers should consider the
effects these physical parameters have on the ease of donning, in order to improve the user
127
experience and increase compliance. However, more work should be conducted in this area in
order to assess these correlations further.
• As noted in Chapter 4, there are issues amongst the sizes of gloves with some users. Gloves
should fit well to the hand of the user, and the sizes measured in correlation with the glove
users in this study, and the previous chapter, show some discrepancies. When donning, a
smaller glove may suit the user by providing a better fit but is more difficult to don. A larger
gloves would be easier to don, but may be loose around the fingers, which was a common
complaint amongst glove users from the questionnaire in Chapter 3. Overall, there are clear
issues highlighted between the best-fit of glove sizes and the recommended fits of the gloves,
which requires further examination.
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Chapter Six: Dexterity and friction
Dexterity was shown to be one of the highest reported issues amongst glove users in Chapter 3.
Whilst it could be argued that gloves have been well assessed for dexterity in the literature, there are
some issues present with these tests (6). The majority of studies assessing dexterity have attempted
to differentiate glove performance by the use of the pegboard tests (6, 9, 12). However, as discussed
in Chapter 2, the results of these studies give somewhat mixed results. Generally, the consensus in
the literature is that medical gloves do not have a significant impairment on dexterity, although in
some cases, there are observable differences in performance between gloves, or the bare hand.
Many of the studies conducted on dexterity tend to compare two materials (normally NRL and NBR),
with the hypothesis that one glove has a superior performance to the other. None of these studies,
however, consider the material properties and the constituents of the gloves. Little work looks at
why some gloves perform better than others. The aim of this chapter is to assess whether
performance differences exist across similar glove materials with different properties. These
properties could then be evaluated when manufacturing materials to predict what constituents and
parameters may impact dexterity and friction. The novelty of this approach, in comparison to
previous literature, considers the chemical differences between gloves of the same core materials, as
well accounting for the physical parameters to assess gloves which have similar materials.
6.1 Introduction
As discussed in Chapter 2 and further highlighted in Chapter 4, manufacturing procedures, bulk raw
materials, and treatment methods differ between gloves composed of the same material (such as
NBR). These differences have been shown to affect the performance of donning in Chapter 4. No
studies could be found assessing a range of gloves with known chemical and physical parameters.
The differences between gloves materials are well known amongst glove users. NBR is stiffer and has
a greater tensile strength than NRL, which gives it the perception of feeling thicker and hindering
performance (7). However, linking these exact differences in properties to the performance has had
little consideration. Two gloves made of NBR, for example, could be manufactured from different
grades of acrylonitrile butadiene, and have different compounding agents, affecting the physical
properties. Therefore, comparing dexterity across studies, where the same glove materials are used,
may yield different results. Dexterity performance is commonly measured via the use of pegboard
tests. The most frequent test encountered in the literature is the Purdue pegboard, as described in
Tiffin and Asher [13] and discussed in Chapter 2. This test can be easily implanted into material
manufacturing plants, and into the glove manufacturing plants for vital glove performance
assessments and requires very little time to complete.
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Furthermore, very little work has been shown considering the tribology of gloves and their effect on
carrying out dexterous tasks. It is possible, that in the tests used, the actual dexterity is not affected
as such by the gloves, but rather the introduction of a different surface contact into the system,
which introduced tribological issues. Tribology plays an important role in the grip of the pins in
studies of this ilk. Thus, without proper assessment of the tribology of gloves, it is difficult to
determine whether the effects gloves have on dexterity are due to movement restriction or are a
result of differences in friction, or a combination of the two.
6.2 Aim and scope

The aim of this chapter is to assess whether different gloves with different properties affect the
dexterity of users. The novelty of this approach will consider the bulk material properties, as well as
the chemical differences between the gloves. Furthermore, the tribological properties of the gloves
will be assessed to understand the friction occurring between the glove films and the smooth metal
components. The Purdue pegboard will be used to assess dexterity as it is a common test. Assessing
whether there are specific properties which affect the tribological properties of the gloves, and the
dexterity of glove users, will help inform glove manufacturers of the most important properties of
the materials they are using. Additionally, this will inform raw material manufacturers how the
chemical nature of the bulk raw materials affects glove properties, which in turn may affect tribology
and consequently the ability of the wearer to carry out dexterous tasks.

6.3.1 Glove selection
The glove materials were chosen with the help of the Synthomer technical centre Sdn Bhd Kluang,
Malaysia. The gloves were selected to reflect what is on the current glove market, available for
purchase. Although rare, some exposure to the accelerants used in the NBR gloves can cause skin
irritation amongst some users. However, there are NBR gloves which are manufactured without
accelerants (162). To negate irritation by these chemicals used in NBR, PVC gloves are also used as
alternatives where required. Although these gloves are not commonly used in the NHS, it is not
obsolete, and is still used around the world (5). Thus, this study also incorporates the use of medical
grade PVC for reference. The gloves used in this study are described in Table 6.1.
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Table 6.1. List of gloves and known constituents.
Glove Glove constituents
Carboxylated acrylonitrile butadiene rubber made with Synthomer
NBR 6348HS 6348HS. High level of acrylonitrile recommended for thinner gloves
with superior break forces. Finished with chlorination treatment.
Acrylonitrile butadiene rubber made with Synthomer 6329.
NBR 6329 Medium level of acrylonitrile recommended for thin gloves with
greater tensile strength. Finished with chlorination treatment.
Acrylonitrile butadiene rubber made with Synthomer 6311.
NBR 6311 Medium level of acrylonitrile recommended for softness. Finished
with chlorination treatment.
Natural rubber latex, with stabilising agents and no bulking
NRL
adulterants. Finished with chlorination treatment
Natural rubber latex with 10% bulking adulterants added. Finished
NRL 10% filler
with chlorination treatment
Medical grade polyvinyl chloride. Finished with chlorination
PVC
treatment.
6.3.2 Physical property measurements

The physical properties of the gloves were measured using a Tinius Olsen (TL-190) tensometer.
Testing was carried out under the same EN standard testing conditions described in Chapter 4 (see
Section 4.3.1). A total of 12 gloves of each set were analysed. The standards for testing were
previously discussed in Chapter 4, stating gloves need to have a ≥6 N break force to pass. However,
this is only true of natural and synthetic rubbers. Thermoplastics, such as PVC, have a lower break
force tolerance at ≥3.6 N (59). The gloves were manufactured and then delivered to the Synthomer
technical centre where they were tested. Therefore, the gloves were not left for a long time period
prior to testing, which was noted as an issue in Chapter 4 whereby the physical properties decreased
over time. Thickness was measured using a Mitutoyo micrometer (quick-mini, ± 0.01 mm) along the
palm, finger, and finger pad, using the method stated in Chapter 4 (see Section 4.3.1).
Stiffness calculations
Stiffness has been calculated as with the gloves used in the Chapter 4. This was done using the
formula given in Equation 4.1. Unless stated otherwise, the stiffness has been compared using the
stiffness obtained at the lowest measured strain (100%) when assessing the modulus. In the donning
Chapters (4 and 5), the stiffness around the 100% strain was likely more replicative of the conditions
when pulling on a glove compared to the 300% and 500% stress. However, the strain of the glove,
once on the hand, is likely to be much lower than 100%. Therefore, the strain used in these
correlations may not be an accurate representation of the strain of a glove once donned on the
hand.
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Size measurements
Using a ruler, a total of ten of each of the gloves were measured for size across the palm, middle
finger length and total length (middle finger-tip to cuff). This was the same procedure described in
Chapter 4. In addition, the width of the fingers was also measured across the base of the middle
finger.
FTIR
FTIR was conducted on the outer surfaces of the gloves to assess differences between the NBR gloves
and the differences between the NRL gloves. This was to highlight any areas where chemistry may
differ in the final glove products of the same bulk material. Analysis was conducted using a Brucker
ATR-FTIR instrument. Each sample was scanned 26 times in the 550-4000 cm-1 region with a
resolution of 4 cm-1. Two sections of each glove were analysed and averaged by OMNIC software.
6.3.3 Task performance assessment

Dexterity was chosen to be a measure of performance for these gloves, due to it being a commonly
reported issues in Chapter 3. The Purdue pegboard (Figure 6.1) was used for this study, as this is
sometimes used in industry as part of a battery of standardized tests when evaluating newly
designed gloves (12, 217). Furthermore, the test is easy to implement into the assessment process as
it is not time consuming or a large piece of equipment. The test measures both gross and an element
of finer dexterity and is comprised of a rectangular wooden board containing 25 holes running
vertically both sides. The top of the board houses four concave dishes. The outermost dishes contain
cylindrical metal pins, whilst the two central dishes house metal washers and collars. The test
consists of four separate tasks, which are as follows:
• Left hand: total number of pins placed into the left column in 30 seconds, using only the left
hand.
• Right hand: total number of pins placed into the right column in 30 seconds, using only the
right hand.
• Both hands: total number of pairs of pins placed into the both the left and right columns at
the same time, in 30 seconds.
• Assembly: total number of assemblies constructed. These assemblies consist of a pin-washer-
collar-washer combination (as in Figure 6.2). The assembly of one structure had to be
completed before moving onto the next. A total score was obtained from the parts of the
structure assembled.
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Figure 6.1. Purdue pegboard test
Figure 6.2. Assembly test construction
The test manufacturers recommend combining scores from all four tests to assess the results.
However, it is deemed that as the pin placement tests are assessing dexterity on a grosser scale than
the assembly test. Consequently, the tests were separated into the ‘combined test’ and the
‘assembly test’ with separate results recorded. In the combined test, scores are given as a total of the
three 30 second pin placement tests, and the assembly consists only of the score obtained from the
one-minute assembly test. Participants were instructed to not pick up any pins which were dropped
in the test, as it was found these were difficult to grab and consumed a large portion of time. Any
dropped pins/parts were counted. The total test combination was conducted in 7 gloving conditions,
once with each of the glove films, and a bare (no-gloves) condition. Tests were carried out in the
Human Interaction Group laboratory at the University of Sheffield with a room temperature range of
22-25°C and 50-57% humidity.
Participants
A total of 21 participants were recruited for the dexterity test. The gloves manufactured and donated
by manufacturing companies for this project were of a “medium” standard size. This is said to be the
133
most common size manufactured and sold in bulk by glove manufacturing companies. As this was the
only size present, participants were selected based on their size preference being a medium. The
participants were aged between 22-42 with no known sensorimotor conditions. Ethical approval was
received by the Research Ethics Committee of the Department of Mechanical Engineering, The
University of Sheffield (No: 016619/022735).
Hand size measurements

The hands of the participants were measured using the same method described in Chapter 4 (see
Section 4.3.2). These were the same measurements recommended by the Health and Safety
Executive (HSE) for sizing gloves for best fit to the hands (149). An additional measurement was
taken in this study, which was across the base of the middle finger of both the participants and the
gloves. Only the middle finger was arbitrarily chosen to save time. This was carried out due to the
results of possible ill-fitting gloves noted in Chapter 4, where it was not considered if finger width
could be a factor in hand insertion. Also, this measurement allowed for the assessment of any
discrepancy between participants perceived best-fit size choice, and those published for
recommendation of best-fit.
6.3.5 Friction methodology

The methodology for the friction analysis follows identically that described in Chapter 4 (see Section
4.3.4). A strip of steel (1.7 × 58 cm) was affixed to the AMTI plate using double sided tape, as in
Figure 6.3. A surface profilometer (Mitutoyo, SJ400 ±0.01 µm) was used to determine the Ra of the
steel surface. The surface was shown to have an Ra of 0.11 µm, a profile of which is shown in Figure
6.4.
Figure 6.3. AMTI plate with steel strip attached.
134
0.4
0.3
0.2
Height (µm)
0.1
0
-0.1
-0.2
-0.3
-0.4
0 1 2 3 4 5 6 7 8
Length (cm)
Figure 6.4. Surface roughness profile of steel strip.
A smooth steel was chosen as to represent the cylindrical metal pins used in the Purdue pegboard. In
addition to this, the smooth metal surface is also representative of some of the commonly
encountered surfaces (bedpans, trolleys, smoothed surface tools) discussed in Chapter 2 (see Section
2.6.3.). The angle between the finger and the surface was kept at approximately 40o, as with previous
studies (57, 90, 104, 137), and held in contact with a near constant desired force as shown in Figure
6.5. The force was shown on a screen, and participants could see the force that was being applied.
This allowed them to maintain a target force for each of the normal loads. Static friction was then
measured by the sliding of the finger down the metal strip. Only static friction was measured for this
study, as this is the friction most relevant in a medical setting (such as holding equipment and
precision work) (114, 116). An example of how static friction is determined has been discussed
previously (see Chapter 4, section 4.3.5). Gloves were donned on the right hand of the sole
participant (male, aged 28). The friction tests were carried out with all six of the gloves and in a no-
gloves condition.
Steel strip
Direction of finger
movement 40°
Force plate
Figure 6.5. Schematic of friction test set-up.
135
Normal force selection
In preceding literature, loads of 0.3-40 N have been used to assess glove friction with varying
surfaces (90, 113, 114, 116). As noted with the donning friction (Chapter 4), these studies rarely
report why certain loads are selected. Forces of 1 N have been used in many studies looking at grip
force, as it has been reported that this is the force used in precision grip (189). Therefore, the target
loads selected in this study are 1, 2, 3, 4 and 5 N. As with the donning methodology in Chapter 4, this
provides an understanding of how friction differs with normal load. Tests were repeated three times
at each load to obtain an average.
6.3.6 Data analysis

As with the previous friction study, the resultant horizontal force was determined prior to the
coefficient of friction (CoF) being calculated (equations 4.2 and 4.3). The data was then processed to
a power fit law, also described in Chapter 4 (see equation 4.4).
The data was assessed for normal distribution following the Shapiro-Wilk test for normality (192).
Where normally distributed, one-way ANOVA was conducted. Statistical significance is set at α=0.05.
ANOVA was followed up with a post-hoc Tuckey’s (HSD). Where non-normally distributed, the non-
parametric Kruskal Wallis test was conducted, followed by the Dunn’s multiple comparison test
where relevant (195). The null hypothesis of the test states that there is no difference between the
performance in both the Purdue tests, and the friction tests, across all glove conditions and the bare
hand. Where a probability (p) of difference is <.05, the null hypothesis is rejected, and a significant
difference is shown between results.
Correlation
Pearson correlation coefficients (r) were also calculated following the same regression analysis
detailed in Chapter 5 (see Section 5.3.3). The regression analysis was used to assess for correlation
between each measured physical property on the tensiometer to both the combined scores and the
total assembly scores for each hand condition. In conjunction with this, as stiffness was found to
correlate to the donning performance, the stiffness of the gloves was also used to assess whether
correlations are shown to both the dexterity and the friction.
136
6.4 Results
6.4.1 Physical characteristics
The results from the physical characteristic testing are shown in Table 6.2, with the stress-strain
curves shown in Figure 6.6. As the various grades of NBR are manufactured to create gloves with
slightly different properties, obtaining gloves of the same film thickness is difficult, as many of the
grade formulations are designed to create thinner gloves. The thickness (T) of NBR 3648 and 6329
are shown to be similar at 0.06 (±0.02) mm and 0.07 (±0.03) mm, respectively. However, the 6311
grade is slightly thicker at 0.10 (±0.05) mm. The thickness of the gloves is shown at the palm only, as
is standard when recording glove thickness (59). Nevertheless, as discovered when measuring the
gloves for donning in Chapter 4, it was noticed that the thickness slightly increased by around 0.01-
0.02 mm towards the fingers. The gloves are shown to have slightly differing mechanical properties
throughout. In the NBR gloves statistical differences are found between all NBR gloves in the break
force (ANOVA F(5, 66)=145.227, p<.001. Table 6.3). No statistical differences are found between the
NRL and NBR 6348HS (Q=0.829, p=.900), however, significant differences are shown between the
other two grades of NBR, which are found to possess high break forces. Large differences are shown
between the NRL and the NRL with 10% filler added. Break force (Fb) (Table 6.3), tensile strength (Ts)
(Table 6.4), elongation (Eb) (Table 6.5), and stiffness (K) (Table 6.6) all show statistically significant
increases when filler is added to the NRL. Significant differences are shown throughout all of the
glove’s stiffness following ANOVA (F(5, 66)=975.567, p<.001), with the exception of the NBR 6348HS
(0.022 (±0.001) N/mm) and the NBR 6329 (0.020 (±0.001) N/mm) gloves (Q=2.672, p=.419). These
two NBR gloves are also shown to have very similar properties with regards to other parameters.
PVC, which is shown to have lower force at break, tensile strength and elongation was also found to
be stiffest (0.065 (±0.004) N/mm), with the highest modulus of all of the gloves used.
137
Table 6.2. Physical properties of gloves.
T (mm) Fb (N) Ts (MPa) Eb (%) K (N/mm)

0.06 6.33 35.80 514.25 0.022
NBR 6348HS
(±0.02) (±0.31) (±2.07) (±9.74) (±0.001)
0.07 7.01 35.28 565.83 0.020
NBR 6329
(±0.03) (±0.74) (±4.30) (±9.15) (±0.001)
NBR 0.10 8.88 29.45 496.58 0.038
6311 (±0.05) (±0.91) (±2.41) (±17.33) (±0.002)
0.10 6.77 20.17 626.83 0.013
NRL
(±0.03) (±0.31) (±0.94) (±24.61) (±0.002)
NRL (10% 0.11 9.12 28.06 837.58 0.010
filler) (±0.06) (±0.52) (±1.24) (±35.95) (±0.002)
0.07 3.87 18.64 348.33 0.065
PVC
(±0.03) ±0.41) (±0.96) (±30.73) (±0.004)
40
35
30
25 NBR 6348HS
Stess (MPa)
NBR 6329
20
NBR 6311
15 NRL
10 NRL (10% filler)

PVC
5
0
0 100 200 300 400 500 600
Strain (%)
Figure 6.6. Stress-strain of gloves.
138
Table 6.3. Results of Tukey’s (HSD) test following ANOVA (t(5, 66)=145.227, p<.001) on the force at
break.
NBR 6329 NBR 6311 NRL NRL (10% filler) PVC

Q=6.598 Q=17.805 Q=0.829 Q=19.233 Q=12.266
NBR 6348HS
P=<.001* P=<.001* P=.900 P=<.001* P=<.001*
Q=11.207 Q=7.427 Q=12.636 Q=18.863
NBR 6329
P=<.001* P=<.001* P=<.001* P=<.001*
Q=18.634 Q=1.428 Q=30.071
NBR 6311
P=<.001* P=.900 P=<.001*
Q=20.062 Q=11.437
NRL
P=<.001* P=<.001*
Q=31.499
NRL (10% filler)
P=<.001*
* denotes statistically significant differences (p<.05).
Table 6.4. Results of Tukey’s (HSD) test following ANOVA (t(5, 66)=635.368, p<.001) on the tensile
strength.

Q=0.786 Q=9.571 Q=23.494 Q=11.629 Q=25.800
NBR 6348HS
P=.090 P=<.001* P=<.001* P=<.001* P=<.001*
Q=8.786 Q=22.709 Q=10.844 Q=25.015
NBR 6329
P=<.001* P=<.001* P=<.001* P=<.001*
Q=13.923 Q=2.058 Q=16.229
NBR 6311
P=<.001* P=.670 P=<.001*
Q=11.865 Q=2.306
NRL
P=<.001* P=.571
Q=14.171
NRL (10% filler)
P=<.001*
* denotes statistically significant differences (p<.05).
Table 6.5. Results of Tukey’s (HSD) test following ANOVA (t(5, 66)=573.568 p<.001) on the
elongation.

Q=7.594 Q=2.601 Q=16.574 Q=47.598 Q=24.426
NBR 6348HS
P=<.001* P=.450 P=<.001* P=<.001* P=<.001*
Q=20.195 Q=8.980 Q=40.006 Q=32.019
NBR 6329
P=<.001* P=<.001* P=<.001* P=<.001*
Q=19.175 Q=50.201 Q=21.825
NBR 6311
P=<.001* P=<.001* P=<.001*
Q=31.026 Q=41.000
NRL
P=<.001* P=<.001*
Q=72.025
NRL (10% filler)
P=<.001*
* denotes statistically significant differences (p<.05)
139
Table 6.6. Results of Tukey’s (HSD) test following ANOVA (t(5, 66)=975.567, p<.001) on the calculated
stiffness at 100% strain.

Q=2.672 Q=24.432 Q=13.234 Q=18.069 Q=65.533
NBR 6348HS
P=.419 P=.001* P=.001* P=.001* P=.001*
Q=27.104 Q=10.562 Q=15.397 Q=68.206
NBR 6329
P=.001* P=.001* P=.001* P=.001*
Q=37.666 Q=42.501 Q=41.102
NBR 6311
P=.001* P=.001* P=.001*
Q=4.836 Q=78.767
NRL
P=.013* P=.001*
Q=83.603
NRL (10% filler)
P=.001*
6.4.2 FTIR
NBR
The FTIR spectra for the NBR gloves are shown in Figure 6.7. NBR 6311 and 6329 show very similar
spectra, except in the 1575-1540cm-1 region. This absorbance corresponds to the carboxylate group
(COO-), which is not present in the NBR 6311 gloves. The presence of the carboxylate may be masked
in the 6311 by the inclusion of stabilisers and materials used to compound the NBR. The most
dissimilar of the three gloves is the 6348HS grades. There is strong peak absorbed by the 6348HS
material at 3690cm-1, which are not present in the other gloves. This peak corresponds to silanol
groups (Si-OH). This strongly indicates that this glove was finished with a silica dip or silica has been
used in the compounding process. Further differences between the 6348HS grade and the other
gloves are highlighted by peaks being present in 6348HS around 1055-1010cm-1. These correspond to
Ester (O=C-O) stretching or aliphatic amine (C-N) bending (209, 210). Differences are expected, due
to the gloves being manufactured by different companies, using different processes, and different
preparation techniques. Changes in the crosslinking, degrees of crystallisation of the polymers and
polymer chain orientation are all factors which can contribute to slight differences in the spectra
between absorbance with different functional groups (209).
140
Figure 6.7. FTIR spectra obtained from NBR gloves. Differences are highlighted in red.
NRL
The NRL gloves are shown to be very similar from the spectra, shown in Figure 6.8. Although no great
differences are present in the spectra, absorbance is noticeably lower in the glove which has had
adulterants added. More absorbance, however, is noticed in the hydroxyl (OH) region between 3550-
3200cm-1 (210). This is showing that the added adulterants could have slightly decreased the
absorbance, likely due to less presence of the natural rubber. Although, the results do show no great
differences are present in the overall spectra between the chemical structures of the different
gloves. It is possible that there are slight differences further down the spectra (>500cm-1 region), but
as the region (1500-500cm-1) has strong similarities in spectra, it is likely the bulking agents have not
changed the overall chemical structure of the glove. As stated with the NBR, the difference in the
polymer chains can cause slight changes in absorbance between spectra.
141
Figure 6.8. FTIR spectra obtained from NRL gloves and NRL gloves with filler.
6.4.3 Glove and hand size

Glove size
The glove measurements are shown in boxplots showing glove/hand length (Figure 6.9), finger length
(Figure 6.10), palm span (Figure 6.11) and finger width (Figure 6.12). These plots show the range of
data (indicated by the error bars), the median indicated by the line in the interquartile box range and
the mean represented by the cross. Additional data points are shown as outliers, which deviate from
the normal distribution within the data. There are some small variations noted between the gloves.
Most difference is present in the glove length, where the largest difference is between PVC (23.32
±0.11 cm) and NBR 6311 (24.91 ±0.20 cm). Slight differences are observed in the finger length also,
where the NBR 6329 gloves shows to be slightly longer at 7.69 (±0.07) cm, whilst the other gloves
range from 7.50-7.68 cm. When the gloves were donned, they were inspected for fit prior to the
experiment being conducted. No great visual issues were present. However there was a little excess
material noted in some participants with NBR 6329 and the PVC gloves in some participants. In the
NBR 6329, the excess was noted at around the tip (finger length= 7.69 ± 0.07 cm), whereas in the
PVC, the excess was noted around the base of the fingers (finger length = 7.61 ± 0.10 cm). However,
this was not excessive and was not indicative of an incorrect size being used (e.g. a smaller size would
have been tight around the palm and possibly the fingers).
142
Figure 6.9. Comparison of the length of gloves used and the length of the participants’ hands.
Figure 6.10. Comparison of the length of middle finger of the gloves used and the length of
participants’ middle finger.
Figure 6.11. Comparison of the palm span of the gloves used and the span of the participants’ hands.
143
Figure 6.12. Comparison of the finger width of the gloves used and width of the participants’ index
fingers.
Participant sizes
As is clear from the results presented in Figure 6.9-6.12, there are differences between the glove
sizes, and the participant hand sizes. However, these size differences are marginal in most cases. The
length of the total glove is larger than the participant’s hands. However, this is normal, as the glove
measurement includes the cuff, which tends to cover the wrist. The most important sizes pertain to
the palm span, finger length and finger width. A larger palm span is observable in the participants,
with a much greater variation. The average lengths of the fingers show similar measurements
throughout the gloves and the participants. The NBR 6311 shows the largest deviation from the
participant’s average (NBR: 7.69 ± 0.07 cm; participants: 7.61 ± 0.13 cm). Most variation is shown in
the finger width, where the NBR 6829, 6311, NRL with filler and the PVC have greater width.
However the difference between the averages is minimal. Comparisons of this nature must be
approached with caution when interpreting, as the gloves are measured when flat. Therefore, it may
appear that the measurements are likely to be different between the gloves and the participant hand
sizes, however these measurements do not account for the geometry of the glove expansion once
the hand is inside.
The hand measurements taken were compared to the HSE size gloving chart (149). All
participants had at least one hand measurement that aligned with that to recommend a ‘medium’
glove sizing. Of the 21 participants, only 4 had a finger length and palm circumference which both
aligned with the medium size category (Figure 6.13). Of the remaining participants, a total of 13
participants had a recommended palm circumference, and 4 had a recommended finger length as
appropriate for medium glove sizing.
144
Large
HSE recommended size
Medium
Palm circumference
Finger length
Small
0 4 8 12 16
No of participants
Figure 6.13. Distribution of recommended glove sizes amongst the participants based on palm
circumference and finger length measurements.
6.4.4 Dexterity
Combined
The results of the combined test are shown in Figure 6.14. Scores have been normalised to show the
differences in gloved score to the bare hand condition (gloved score – bare hand score). As the data
was found to be non-parametric, the Kruskal Wallis test was conducted, which shows significantly
different results across the conditions (H(6)=41.014, p=<.001). All gloves are shown to significantly
reduce performance, with a lower number of pins placed when compared to the bare hand following
the Dunn’s test (p=<.001, Table 6.7). However, the difference between some of the results is not
large. For example, when the NRL with filler was worn, the score was an average of 42.5 (±5.90), NBR
6348HS with an average of 42.10 (±5.82) and the bare condition an average of 46.14 (±5.60). The
bare hand also showed less pins being dropped, with only 5 people dropping pins, and only 6 pins
were dropped across the entire tests (0.42 pins on average, Table 6.8). Across the NBR gloves, the
6311 grade scored the lowest when donned, across all participants, with an average score of 37.71
(±5.90). Only one significant difference is noted between participants with the NBR gloves, which is
between the 6311 and the 6348HS grades (Z=2.015, p=.022). Although the dexterity performance
was not as good as when the 6348HS glove was worn, the 6329 glove showed the least pins dropped,
with only 7 participants contributing to dropping 11 pins (0.52 on average). In the NRL gloves, the
difference in scores when these two gloves are donned is not significantly different. However, the
NRL which included filler allowed the participants to perform better than when the other gloves were
145
donned. When the PVC glove was donned, performance was worse than any of the other gloving
conditions, and on average, 2 pins were dropped per person.
Dropped pins Normalised pegboard score
PVC
NRL (10% filler)
NRL
Glove
NBR 6311
NBR 6329
NBR 6348
-12 -10 -8 -6 -4 -2 0 2 4
No of pins
Figure 6.14. Normalised results (gloved score – bare hand score) of the combined test (left hand,
right hand and both hands) in the Purdue Pegboard test. Error bars denote standard error.
Table 6.7. Post-hoc Dunn’s test results conducted after Kruskal-Wallis on combined test scores
(H(6)=11.014, p=<.001).
NBR
Glove NBR 6329 NBR 6311 NRL NRL (10% filler) PVC
6348HS
Z=3.090 Z=3.076 Z=2.346 Z=3.090 Z=2.978 Z=2.652
No gloves
p=<.001* p=<.001* p=<.001* p=<0.001* p=<.001* p=<.001*
NBR Z=0.028 Z=2.015 Z=0.665 Z=0.048 Z=3.174
6348HS p=.511 p=.022* p=.253 p=.519 p=<.001*
Z=0.048 Z=0.327 Z=0.867 Z=3.317
NBR 6329
p=.104 p=.628 p=.193 p=<.001*
Z=0.066 Z=2.748 Z=0.533
NBR 6311
p=.254 p=.003* p=<.297
Z=1.447 Z=1.896
NRL
p=.074 p=.029*
NRL (10% Z=3.115
filler) p=<.001*
146
Table 6.8. No of pins dropped in the combined test.
No of participants
Glove Pins dropped Average
who dropped pins
No gloves 6 5 0.29
NBR 6348HS 16 10 0.76
NBR 6329 11 7 0.52
NBR 6311 23 13 1.10
NRL 23 13 1.10
NRL (10% filler) 19 13 0.91
PVC 42 18 2.00
Assembly
The results of the assembly test are shown in Figure 6.15. As with the combined test, the scores have
been normalised (gloved score – bare hand score) to compare dexterity to the bare hand condition.
As fewer pieces were assembled on average when compared to the no-gloves condition, this shows
that dexterity was impaired with all gloves. The Kruskal-Wallis test was conducted due to non-
parametric data, which shows statistically significant differences between the glove conditions
(H(6)=31.241, p=.001). Table 6.9 shows the results of the post-hoc Dunn’s test, which shows
significantly less pins were placed when NBR 6311 (27.86 ±5.19), NRL (30.62 ±7.16), and PVC (25.10
±4.66) are compared to the bare hand condition (35.57 ±5.97) (p<.05).
In the NBR gloves, the participants wearing the 6311 grade performed significantly worse
than when the 6329 (32.52 ±6.01, Z=2.067, p=<.018) and the 6348 (31.86 ±6.37, Z=1.774, p=.038)
gloves were worn. A superior performance is observed when the adulterated NRL (32.52 ±6.98) was
worn, when compared to the unadulterated NRL (30.62 ±7.16). As with the combined test,
performance was lowest with the PVC glove, which is statistically significant across all glove
conditions (p<.05), except with the NBR 6311 (Z=0.726, p=.234) gloves. The number of parts dropped
was higher when the PVC glove was worn, with 3.1 parts dropped on average. Across 12 of the
participants, 29 parts were also dropped when the 6311 NBR glove was worn (average 1.38 across all
21 participants), as displayed in Table 6.10. In the gloved conditions, the least amount of dropped
pins was observed when the adulterated NRL gloves were worn, which showed an average of 0.43
parts dropped. It was also noted that participants knocked off the top washer in the already
assembled parts when completing other assemblies. Participants were asked to ignore the washers
that had been knocked off and were counted as complete assemblies. The knocked off washers were
counted and are also shown in Table 6.10. It is shown that the when the PVC gloves were donned,
1.76 parts were knocked off on average, whereas when the NBR 6348HS and adulterated NRL were
donned, only 0.22 washers were knocked off on average. In comparison to the bare hand condition,
147
gloves appear to incur this knocking off of washers, as only one participant knocked one washer off
over the course of the tests in the bare hand condition.
Dropped parts Normalised assembly score
PVC
NRL (10% filler)
NRL
Glove
NBR 6311
NBR 6329
NBR 6348
-12 -10 -8 -6 -4 -2 0 2 4
No of parts
Figure 6.15. Normalised results (gloved score – bare hand score) of the assembly test of the Purdue
Pegboard test. Error bars denote standard error.
Table 6.9. Post-hoc Dunn’s test results conducted after Kruskal Wallis on assembly test scores
(H(6)=31.241, p=<.001).
NBR NBR NRL (10%

Glove NBR 6311 NRL PVC
6348HS 6329 filler)
Z=1.911 Z=1.70 Z=3.163 Z=1.943 Z=0.871 Z=3.4408
Bare
p=.208 p=.121 p=<.001* p=.026* p=.192 p=<.001*
Z=0.792 Z=2.067 Z=0.454 Z=0.256 Z=3.548
NBR 6348HS
p=.767 p=.018* p=.325 p=.665 p=<.001*
Z=1.774 Z=0.020 Z=0.845 Z=3.6843
NBR 6329
p=.038* p=.492 p=.801 p=.001*
Z=0.971 Z=2.053 Z=0.726
NBR 6311
p=.166 p=<.020* p=.234
Z=0.391 Z=2.326
NRL
p=.348 p=.010*
NRL (10% Z=0.028
filler) p=<.001*
* Indicates statistical significance (p<.05)
148
Table 6.10. Number of pins dropped, and washers knocked off in the assembly test.
No of
No of
participants
participants Average of Average of
Parts Knocked who
Glove who all all
dropped off contributed
dropped participants participants
to knocking
parts
pins off
Bare 2 2 0.1 1 1 0.05
NBR
10 6 0.48 6 6 0.29
6348HS
NBR 6329 21 16 1.00 7 5 0.33
NBR 6311 29 12 1.38 15 9 0.71
NRL 25 14 1.19 6 4 0.38
NRL (10%
9 7 0.43 6 3 0.48
filler)
PVC 49 20 2.33 37 19 1.76
6.4.4.1 Physical property correlation

As mentioned in Chapter 4, as industries measure glove parameters to EN standards, correlations
were drawn between the measured physical properties and the dexterity scores obtained from both
the combined and the assembly pegboard test. In addition to this, the sample stiffness has been
calculated, as previously described (equation 4.1), and correlated to the dexterity performance.
Moderate positive correlation is noted in the force at break in both the combined (r=.539) and
assembly tests (r=.627), as displayed in Table 6.11. The correlation tests also indicate that the
elongation properties have stronger positive correlation in the assembly tests (r=.774), but a weaker
negative correlation in the combined tests (r=.466). None of these correlations show any significant
differences (p>.05). On the other hand, stiffness is shown to have statistically strong correlations with
both the combined (r=-.888; p=.018) and the assembly tests (r=-.930; p=.007), as shown in Figure
6.16. The stiffer PVC glove has shown to decrease the average pegboard score by 14.9 (±10.5) % with
the combined test, and by 21.0 (±12.4) % in the assembly test, when compared to the high scoring,
least stiff NRL (with filler). This indicates that the less stiff the glove is, the better the performance in
the dexterity tests.
149
Table 6.11. Pearson’s correlation coefficients of measured physical parameters.
Combined Assembly
r p r p
Δ Δ
Force at break .539 .270 .627 .184
Tensile Strength -.247 .637 .488◊ .326
Elongation -.446◊ .427 .774Δ .071
¤ ¤
Stiffness at 100% strain -.888 .018* -.930 .007*
r= Pearson correlation score. p= statistical significance. denotes weak correlations,◊ denotes
Δ
moderate correlations ¤ denotes strong correlations * denotes statistically significant differences

(p<.05)
Combined Assembly
45
NRL (filler) NBR 6348HS
R² = 0.7905
40 NRL
NBR 6329
35 NRL (filler) PVC
NBR 6311
NBR 6348 HS
NRL
Pegboard score
30
NBR 3629 R² = 0.8639
25 NBR 6311 PVC
20
15
10
5
0
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07
Stiffness (N/mm)
Figure 6.16. Pearson correlation graph of combined Purdue pegboard scores to the stiffness
parameter of the gloves used.
6.4.5 Friction
The results of the static friction for each glove and the CoFs are shown in Figure 6.17 (a-b). In this
experiment, the gloves have shown to reduce friction when compared to the no gloves condition.
Friction increases across the increase in load with all materials and the no-gloves condition.
Noticeably, the skin CoF reduces between the minimum (~1 N) and maximum (~5 N) target load,
whereas the glove CoF increases slightly between the two extremes. ANOVA tests were conducted at
each load and statistically significant differences between results are indicated (1N F(6,14)=451.186,
p=.001; 2N F(6,14)=625.368, p=.001; 3N F(6,14)=613.098, p=.001; 4N F(6,14)=593.868, p=.001; 5N
F(6,14)=591.329, p=.001). The results of the post-hoc Tukey’s test are shown in Tables 6.12-6.16,
showing that the bare hand condition has significantly higher CoF than each of the glove conditions
at each given load (p<.05). Between gloving conditions, the NRL gloves produce the highest CoF,
150
ranging between 1.22 (±0.12) and 1.52 (±0.08). There is little difference between CoFs across all
loads with the NRL and the NRL with filler, which show no statistically significant differences at each
load. However, the CoF of the NRL with filler is slightly higher on average. For example, at ~2 N, the
NRL without filler averages a CoF of 1.60 (±0.02) and when filler is added the CoF is slightly increased
at 1.65 (±0.03). A similar result is shown for the ~5N load, however the NRL is shown to have a
slightly higher friction (µ= 1.52 ±0.02) than the NRL with filler (µ= 1.50 ±0.01). Among the different
NBR grades, 6311 produces a higher friction than the 6329 and 6348HS gloves. The CoF of the 6311 is
shown to be significantly different from all gloves, with the exception 6329 at the 4 N load
(Q=11.859, p=.082). Both the 6348HS and 6329 grade gloves produce similar friction coefficients at
each load, with no significant differences. The lowest friction is produced in the PVC gloves, showing
friction coefficients between 0.51 (±0.05) at the minimum applied force, and 0.69 (±0.01) at the
maximum applied force. The results of all CoFs produced in the PVC condition show statistically
significant differences from all other gloves at each load (p<.05).
a) 9 b) 2.5
8
NBR 6348
2 NBR 6348
7
NBR 6329
NBR 6329
6
NBR 6311
1.5 NBR 6311
5
CoF (N)
Friction Force (N)
NRL NRL
4
NRL 10% 1 NRL 10%
Filler Filler
3
PVC PVC
2 0.5
No Gloves No gloves
1
0 0
0 2 4 6 0 2 4 6
Load (N) Load (N)
Figure 6.17 (a-b). Friction and CoFs of different gloving conditions and no-glove condition. Error bars
denote standard error.
151
Table 6.12. Results of Tukey post-hoc test for all glove conditions at 1 N target load. ANOVA:
F(6,14)=451.186, p=.001.
NBR NRL (10%

Glove NBR 6329 NBR 6311 NRL PVC
6348HS filler)
Q=56.670 Q=50.924 Q=47.439 Q=33.688 Q=29.849 Q=62.592
Bare
p=<.001* p=<.001* p=<.001* p=<.001* p=.001* p=<.001*
NBR Q=5.149 Q=9.231 Q=22.927 Q=26.821 Q=5.922
6348HS p=.216 p=.001* p=.001* p=<.001* p=.009*
Q=3.485 Q=17.236 Q=21.075 Q=11.668
NBR 6329
p=.182 p=<.001* p=.001* p=.001*
Q=13.751 Q=17.590 Q=15.153
NBR 6311
p=.001* p=.001* p=.001*
Q=3.839 Q=28.904
NRL
p=.122 p=<.001*
NRL (10% Q=32.743
filler) p=<.001*
* denotes statistical significance (p<.05)
F(6,14)=625.368, p=.001.
NBR NRL (10%

6348HS filler)
Q=134.870 Q=132.12 Q=115.83 Q=74.733 Q=71.360 Q=145.54
Bare
p=<.001* p=<.001* p=<.001* p=<.001* p=.001* p=<.001*
NBR Q=2.571 Q=19.042 Q=60.140 Q=63.513 Q=10.669
6348HS p=.084 p=<.001* p=.001* p=.001* p=.007*
Q=16.291 Q=57.389 Q=60.762 Q=13.420
NBR 6329
p=.001* p=.001* p=<.001* p=<.001*
Q=51.098 Q=44.471 Q=29.711
NBR 6311
p=.001* p=.001* p=.001*
Q=3.373 Q=70.810
NRL
p=.273 p=.001*
NRL (10% Q=74.183
filler) p=.001*
152
F(6,14)=613.098, p=.001.
NRL (10%
Glove NBR 6348HS NBR 6329 NBR 6311 NRL PVC
filler)
Q=59.106 Q=58.201 Q=41.064 Q=21.400 Q=20.940 Q=65.150
Bare
p=<.001* p=<.001* p=<.001* p=<.001* p=.001* p=<.001*
NBR Q=0.905 Q=12.042 Q=37.707 Q=38.167 Q=6.044
6348HS p=.901 p=.001* p=.001* p=<.001* p=.011*
NBR Q=11.137 Q=36.802 Q=37.262 Q=6.942
6329 p=<.001* p=.001* p=.001* p=.003*
NBR Q=25.664 Q=26.125 Q=18.086
6311 p=<.001* p=<.001* p=.001*
Q=0.460 Q=43.751
NRL
p=.890 p=<.001*
NRL (10% Q=44.211
filler) p=.001*
F(6,14)=593.868, p=.001.
NBR NRL (10%

6348HS filler)
Q=57.178 Q=56.512 Q=44.653 Q=18.821 Q=19.087 Q=63.391
Bare
p=<.001* p=<.001* p=<.001* p=<.001* p=.001* p=<.001*
NBR Q=0.666 Q=12.525 Q=38.358 Q=38.091 Q=6.213
6348HS p=.901 p=.093 p=<.001* p=.001* p=.008
Q=11.859 Q=37.691 Q=37.425 Q=6.878
NBR 6329
p=.182 p=.001* p=<.001* p=.003
Q=25.833 Q=25.566 Q=18.737
NBR 6311
p=.021* p=.001* p=<.001*
Q=0.267 Q=44.570
NRL
p=.899 p=<.001*
NRL (10% Q=44.304
filler) p=.001*
153
F(6,14)=591.329, p=.001.
NBR
Glove NBR 6329 NBR 6311 NRL NRL (10% filler) PVC
6348HS
Q=51.918 Q=51.073 Q=37.515 Q=8.99 Q=9.951 Q=58.877
Bare
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
NBR Q=0.845 Q=14.403 Q=42.926 Q=41.961 Q=6.960
6348HS p=.582 p=<.001* p=.001* p=<.001* p=.003*
Q=13.556 Q=42.081 Q=41.117 Q=7.805
NBR 6329
p=.001* p=.001* p=<.001* p=.001*
Q=28.524 Q=27.558 Q=21.362
NBR 6311
p=<.001* p=.001* p=.001*
Q=0.966 Q=49.886
NRL
p=.900 p=.001*
NRL (10% Q=48.923
filler) p=<.001*
6.4.5.1 Correlation to performance and glove stiffness

Performance
Weak correlations are noted between the dexterity performance scores obtained and the CoF at
each load (Table 6.17). The most pertinent load is likely to be at the lower 1 N grasp force (218),
which shows no correlation with the combined test (r=.087), but a slightly stronger correlation is
observed in the assembly test (r=.397). This implies that dexterity performance is not greatly
influenced by the glove friction.
Table 6.17. Correlation of friction at each load to the dexterity performance scores.
Force (N)
1 2 3 4 5
r .087 .447 .425 .413 .409
Combined
p .871 .374 .401 .416 .421
r .397 .423 .402 .392 .391
Assembly
p .436 .403 .429 .442 .443
r= Pearson correlation score. p= statistical significance.
Stiffness
The glove stiffness has been compared with the friction coefficients obtained, which are shown in
Table 6.18. Moderate correlations are shown between the friction and the stiffness of the different
gloves. However, none of these results show statistical significance. The greatest correlation is shown
at the 1 N force (r=-.735; p=.096), which is shown in Figure 6.18. The correlations imply that the
154
stiffness affects the frictional properties of the gloves, whereby the stiffer the glove, the lower the
friction coefficient.
Table 6.18. Correlation of friction to glove stiffness.
Force (N)
1 2 3 4 5
r -.735 -.679 -.665 -.659 -.663◊
◊ ◊ ◊ ◊
p .096 .138 .150 .155 .151

◊
r= Pearson correlation score. p= statistical significance. denotes moderate correlations
1.4
NRL (filler)
1.2 NRL
1
NBR 6311
0.8 NBR 6329
CoF
NBR 6348HS PVC

0.6
0.4
0.2
0
0.000 0.010 0.020 0.030 0.040 0.050 0.060 0.070
Stiffness (N/mm)
Figure 6.18. Correlation of stiffness to the friction coefficient at 1 N (r=-.735).
6.5 Discussion
6.5.1 Performance and friction
The results show, on the whole, that dexterity is adversely affected when gloves are donned
compared to the bare hand. This was also shown with previous studies (63, 70, 75, 96) which
compare dexterity with a pegboard using NBR or NRL gloves. However, the nature of the glove
materials used in this study is much more understood than in previous studies, as the constituents
are known, and the physical parameters have been studied.
Carré et al. (90) studied the friction of NRL surgical gloves. The authors found that friction
was reduced when gloves were worn, compared to that of bare skin. Similar findings were produced
in this study. Furthermore, this study has highlighted that gloves of the same bulk material have
different frictional properties, and in turn, different dexterity performance scores. NBR 6311 shows
to have the highest friction of the three NBR gloves, and the lowest performance scores. Although
NBR 6348HS and 6329 show similar frictional properties, the performance was overall better with the
155
6348 gloves. In addition to adhesion of the gloves to the metal, contact areas could be the reason for
the differences in frictional performance (189). This is a limitation of studies involving gloves from
different manufacturing plants, as different formers and pattern imprints may be used. The
differences are visible in Figure 6.19 which shows the NRL (Figure 6.19a), NBR (Figure 6.19b), and
PVC (Figure 6.19c) finger patterns. The PVC shows to have no visible pattern on. Thus, in comparison
to the other gloves used, the PVC glove is ‘smooth’. The NRL shows to have a rougher texture all over
the glove surface, whereas the NBR shows to have a smooth area which is then textured at the finger
pad only. This grooved surface may be the cause for the reduction in friction between the textured
gloves. In the skin, the rough, grooved finger pad will cause a reduced contact area, however
moisture in the skin will cause capillary adhesion, whereby the finger will have more interaction with
the metal due to the asperity contact and surface attraction, which has been discussed in Chapter 4.
At higher loads, the finger ridges are deformable, which will cause an increased contact area through
rough-rough asperity contact, to help gain friction (219). When gloves are donned, as no moisture is
present, the capillary adhesion between the glove and the metal is reduced severely, leading to a
decrease in friction. As the NBR surface appears more textured, there will be less contact of the two
surfaces.
Figures 6.20a-c. Figure a shows the NRL glove fingertip, b shows NBR 6311 and c shows the PVC.
Positive correlations were noted between the friction of the gloves and the stiffness, a correlation
also noted in Chapters 4 and 5. The NRL gloves have a lower stiffness, indicating that they are easier
to deform. Thus, when the greater forces are applied, the more the NRL will deform and increase the
contact surface area, increasing the friction. As the NBR is more rigid and stiff, there will be less
deformation and the rough applied pattern will keep the surfaces separated, resulting in lower
156
contact areas and lower asperity contact. Therefore, in the NBR and NRL gloves, the lower stiffness
allows for deformation of the local asperities, likely inducing local welding and making the static
friction harder to overcome. On the other hand, in the stiffer PVC, the asperities will sit atop the
smoother surface and little deformation will occur. Thus, friction is lower in the smoother PVC glove,
as shown in Figure 6.20. This is similar to the friction between the skin and the gloves discussed in
Chapters 4 and 5. However this time, the deformability of the glove is increasing friction by
increasing the contact of asperity junctions, whilst the stronger gloves do not deform, reducing
friction. In Chapter 5 it was shown that the donning gloves had different frictional behaviours based
on the stiffness. The higher stiffness exhibited more stick-slip as the finger was run down the glove,
whereas the less stiff gloves exhibited more movement as the glove stuck to the fingers more.
However, with the gloves used in this study, different thicknesses are apparent throughout the
gloves, which may have an effect on the friction due to the differences in bulk material properties.
Figure 6.20. Schematic of the glove-metal asperity contact.
Due to the translucent nature of both the PVC and NRL, surface roughness details were unobtainable
as the method of surface roughness used deploys optical microscopy. However the physical glove
properties appear to be a greater factor than the surface roughness. The PVC is also shown to have
the poorest performance, with more pins/assembly parts being dropped on average than any other
condition. This leads to the inference that the frictional properties have led to the differences in
performance.
Capillary adhesion
The moisture in the bare skin is a reason for the differences in performance in the bare hand
condition. Although this is not shown in the results due to the normalisation, there was some
variation in the results. The reason for these differences is mostly down to the dexterity of each
157
individual conducting the test. In conjunction with this, however, the friction when grabbing the pins
is also an important factor to consider. It is important to note all gloving conditions either decreased
performance or matched the score in all participants. No one person performed better in any gloved
condition than their no gloves score. An increase in surface contact area is possible due to the
introduction of moisture in the skin. This can cause the two surfaces to pull together, and friction will
greatly increase. However, this is applicable to hard but rough surfaces, and not necessarily the case
when one of the materials is soft (189, 220). A study by Persson (105), shows that when water is
decreased between elastically deformable solids, the area of contact greatly increases. This effect
has been demonstrated and discussed in Chapter 4 (see Section 4.5.1). However, this friction was
dependent on two deformable solid materials, whereas this friction is between the skin and metal
surface. This effect of the increase in friction is said to be dependent on the Young’s modulus of the
materials in contact (105, 121). In the skin, the top layer (stratum corneum) will have a varied
Young’s modulus between participants, due to the differences in components in the skin, and the
moisture content (221). Where the bare hand test is being conducted, the Young’s modulus of the
stratum corneum is the most salient factor in whether capillary adhesion will occur to increase
friction. No water or increased moisture was used in this study, therefore the differences in capillary
adhesion between the skin and the metal is likely to not be as great an effect as discussed in previous
chapters. However, it could be argued that this adhesion is vital for precision control when placing
the pins. When gloves were donned, which contain no moisture, the friction of all gloves decreased
in comparison to the bare hand, as demonstrated with the sole participant in the friction study. This
is possibly because the adhesion between moisture, in the stratum corneum, and the metal is
blocked by the glove. It may be possible that this capillary adhesion could allow for a better grip and
sensibility regarding the task, allowing for greater precision when placing the pins/parts.
The role of capillary adhesion in grip has been studied previously, revealing it may only have
a little effect, if any, on the role of friction. Pailler-mattéi and Zahouani (222) studied the ‘pull off’
force of a steel probe on the forearm skin and found the capillary adhesion forces to be around 5
mN. The small values, which are a small percentage of the force applied in normal tactile exploration,
are also found throughout other studies (104, 218). Therefore, there is little evidence suggesting that
the capillary adhesion of the skin is a significant factor in friction in this study. However, it should not
be ruled out as a factor entirely. It is likely that the frictional differences observed in this study are
combined a result of the deformability of the gloves as previously discussed, leading to an increase or
decrease of asperity contact, which may be shaped by capillary adhesion in the skin.
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It could be argued in these tests that the measurements conducted when gloves are worn depend on
the glove friction, rather than dexterity. As, for example, the lower friction in the PVC gloves lead to
more pins being dropped in the performance tests. However, this study shows this is not likely to be
the case and is more of a combination of dexterity and friction. As the loads used by the participants
in the dexterity test will vary, more force could be applied to hold and place the pins/parts. In order
to assess the correlation between the friction of the gloves and the performance accurately, there
needs to be a constant force applied with each glove in order to fairly assess these parameters.
However, the fact that there are correlations between the stiffness of the gloves, with both the
friction and the performance implies that friction is important. For example, the NRL gloves show
differences in performance, but similar frictional behaviour. When filler is added to NRL, the gloves
become less stiff than when no filler is added. However, there are slightly different performance
scores between the two gloves. Additionally, there are positive correlations noted between both the
elongation of the gloves and the performance. In the combined test, this correlation is negative. The
correlation between elongation and the performance in the assembly is stronger, which shows better
correlation between the score and the elongation. This correlation was also noted between the
donning time and elongation in Chapter 4, giving further evidence that elongation may provide an
indication to the performance of examination gloves.
6.5.3 Effects of gloves on dexterity

There is little discussion in the literature on how gloves affect dexterity enough to conclude that a
decrease in performance is detrimental. Proud, Miller, Bilney, et al. (223) studied the use of the
Purdue pegboard with patients diagnosed with Parkinson’s disease. The study compared the results
to those who did not have Parkinson’s, and found on average, those with the diagnosis placed 12.4
fewer pins. In this study, the greatest difference to the bare hand was found to be 10 fewer pins
placed on average when the PVC glove was worn, indicating a greatly reduced performance. Morris
(224) and Korniewicz, Garzon, Seltzer, et al. (225) suggest that dexterity is affected by gloves through
inducing hand fatigue over time. However, little work has been conducted into how this causes
fatigue, and results in a loss of dexterity. From the review of the work looking at dexterity, it is clear
that many of these types of tests are short and succinct. For example, this test took the participants
each 2.5 minutes to do all of the tests, with breaks in between whilst the board was cleared, and
participants rested. This is the case for many of the tests conducted in the literature, and far fewer
test conditions are normally used (6, 9, 12). Therefore, it is more likely that the reason for dexterity
loss is through the gloves restricting lateral movement of the joints between the fingers, as well as
movement of the thumb both horizontally and laterally, rather than solely a time-dependent issue.
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Hubner, Goerdt, Mannerow, et al. (226) also show that gloves tend to have a higher failure rate
(more perforation) between the index finger and the thumb, indicating more stress is put in this
area. It is likely that this wear is present as the glove is stretched and relaxed more due to the natural
movement involved in gripping. In this study, participants grabbed parts predominantly with a pinch-
grip, holding pins between the thumb, index, and middle finger as in Figure 6.21. Thus, if the glove is
restricting the natural movement of this thumb-finger area, the participant may struggle to conduct
the task when trying to grab the pins.
Figure 6.21. Pinch grip exhibited with pin grabbing and placement amongst the participants.
It is thought that if the gloves are stiffer, this would be harder to move more naturally, due to the
resistance of stretching from the glove. The results of this study do provide some evidence for this.
The PVC gloves scored the lowest on average in both of the tests. This glove was shown to be the
stiffest of all of the gloves used, whereas the NRL which contained adulterants was the least stiff and
performed better overall. In addition, the stiffer nitrile glove (NBR 6311), was shown to perform the
worst out of all the NBR gloves used. In conjunction, correlations were found between the glove
stiffness and the performance score with both of the tests.
To highlight the effects these different gloves may have on the restriction of movement a
small test was produced to assess how hand span may be decreased with donned gloves. Figure 6.22
shows the hand is placed as wide as possible on a series of grids (1cm × 1cm). Each of the gloves was
then donned and placed onto the grid to assess any visual reduction in hand span. However, this is a
rudimentary test which would require a greater assessment with a larger number of gloves, and
participants with different hand sizes, in order to form a solid conclusion on the hypothesised effects.
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Nevertheless, it can be seen that when the stiffer PVC glove is donned, the glove restricts adduction
of the thumb. Thus, when doing tasks quickly, the restriction may have an effect on the psychomotor
ability due to the small differences in freedom of movement. In addition to this, it can be seen there
is excess material between the fingers with the PVC, but not with the NRL, highlighting issues with
the sizing of gloves and further indicating a restriction of movement of the fingers.
Figure 6.22. Left: hand spanned without gloves. Centre: hand spanned with NRL. Right: hand and
spanned with PVC gloves.
The knocking of the washers in the assembly test strengthens this reasoning. A total of two washers
were accidentally knocked off the completed assemblies in the bare hand condition. However, when
gloves were donned, more washers were knocked off. The PVC glove shows a greater number of
washers being knocked off. The knocking off of the parts could be due to a combination of the
compression of the hands, the gloves restricting movement, and the overall feel of the gloves. This
indicates that once the gloves are donned, the movements are less co-ordinated, showing that the
gloves do decrease dexterity. A greater bank of gloves should be analysed, with known chemical
compositions, as in this study, in order to fully understand the effects these gloves have on dexterity.
It was previously postulated by Mylon et al. (8) that the combined portion of the Purdue pegboard
test is redundant for use in glove assessments. However, this test is becoming a more widely used
and standardised test for motor skill assessments. Using the board between studies, where the exact
components and physical characteristics of the gloves are known could prove useful for assessments
by manufacturers, as this study shows measurable differences.
Comparison of common gloves
A common theme noted in the review of literature in Chapter 2 was the frequency of studies
comparing NRL and NBR gloves. This leads to a underlying theme in the literature of comparing the
two gloves, where similar or slightly differing results are shown (6, 9, 12). Although this study is
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similar to the other studies in respect to this comparison, the addition of the chemical knowledge
and differences between the bulk materials is advantageous for better understanding the effects of
gloves on performance. As discussed earlier, comparing studies where chemical/material information
is not ascertainable does not allow for a fair comparison. It would seem that the comparison of NRL
and NBR gloves has reached its course without the fundamental understanding of why or how
dexterity is affected. Very little differences exist between the two gloves in terms of performance in
this area. However the NRL does provide slightly better dexterity than the different grades of NBR.
Although the NBR does show remarkably similar results. Future work in this area should focus on
much longer tasks, looking at the induction of hand fatigue proposed by Morris (224) and Korniewicz
et al. (225) whilst giving great consideration to the physical and frictional properties. Whilst it could
be argued that examination gloves are used for a short amount of time, therefore studies looking at
prolonged use would be more pertinent to surgical gloves, examination gloves are worn across many
fields. In clinical settings, a frequent glove change is encouraged to avoid cross contamination.
However, in roles such as mechanics, forensics, cleaning, laboratory work etc., gloves will be worn
much longer without the need for frequent changes.
6.5.4 Glove size and fit

There is some mixed messaging regarding how the fit of gloves affects dexterity. Drabeck et al. (99)
speculates that the thickness of NRL surgical gloves impairs the dexterity of glove users, and the
dexterity is rather unaffected by the glove size. On the other hand the authors found in another
study that wearing vinyl gloves did not impair manual dexterity (97). Mylon et al. (70) also showed
that wearing gloves larger than the perceived best fit diminished dexterity when using the Purdue
pegboard. Although differences in glove size performance was not assessed in this study, it is clear
that glove sizing is an inherent issue.
It was discussed in Chapter 4 how the fit of gloves may not account for the general
population, which has also been highlighted in this study. Of the 21 participants only four had gloves
that fit into the HSE guide chart. In Chapters 4 and 5, only four of the 20 participants used in both of
the donning studies had gloves that fit the participants recommended size. Ooka and Morimoto
(227) assessed the perception of fit on 325 female dental students. They found the participants had
‘optimum’ perceived best-fit when the gloves had slightly shorter fingers than the participant. This
study shows similar findings, with the gloves being shorter than the fingers, which shows conformity
to the fingers. The less stiff the glove, the better the gloved looked to fit. However, Ooka and
Morimoto’s (227) findings are only applicable to the less stiff gloves. As discussed around Figures
6.10-6.13, there are areas where the gloves are visibly shorter than the fingers in the PVC gloves.
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However, the gloves are all the same gross size (medium), and therefore should have very little
difference between the sizing and fit. Measurement of the gloves themselves, however, do show
very slight differences in the sizes of gloves. The most variation is noted at the total length, which is
likely a result of the difference in the dipping process and/or how far down the glove is beaded.
More emphasis should be placed on the differences in measurements at the finger length, palm
span, and finger width. The palm span was shown to differ most in the NBR 6311 and the PVC gloves.
Although the difference is not great between the two gloves, it would indicate that a perfect fit with
the NBR 6311 glove would lead to some excess material with the PVC glove. This is likely to arise due
to a possible variation in former size, rather than the manufacturing process.
Glove formers and fit
The glove formers used to manufacture gloves can be purchased by different manufacturers, and
due to the difference in the glove sizes there is a suggestion that the formers differ in geometry, even
in the same sizes. One company was found selling two different formers for medical examination
gloves with sizes extra small, small, and medium. When compared, the formers were found to have
different dimensions, as shown in Table 6.19 (228). As the total glove length is dependent on the
manufacturing dipping process, the height is arguably unimportant, as long as the gloves can be
dipped to similar lengths. However, there are differences highlighted between the formers. As much
as a 2 cm difference is shown in the medium sized former at the height. The greatest difference
noted at the palm circumference is in the extra-small gloves (6 mm difference). The wrist
circumference with the greatest difference is noted in the extra-small and the medium formers (2
mm difference).
Table 6.19. Former sizes obtained from one former manufacturer (228).
Extra-small Small Medium

Former 1 Former 2 Former 1 Former 2 Former 1 Former 2
Height (mm) 400 380 400 380 400 380
Palm circumference (mm) 170 164 177 178 202 202
Wrist circumference (mm) 151 149 166 167 180 182
A question arises as to why these medical glove formers are different geometries for the same sized
gloves. There is no literature guidance surrounding the shrinkage of films once removed from the
former, such as if particular gloves shrink to a particular size when removed. As the chlorination
process, and other treatment processes, harden the surface of the glove, it is highly unlikely that
there is any significant film shrinkage once the glove is stripped from the former (51). As the gloves
being made are sized in increments of extra-small, small, medium, large, and extra-large, it is likely
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that that one former size should be used to yield the respective glove size, regardless of the bulk
material being used. This size variation between formers, that is prevalent throughout the industry,
causes fitting problems, whereby one user may be a between sizes or have to use different sizes for
different brands. In an emergency, this causes complications with the ability to don the gloves (as
highlighted in Chapters 4 and 5), and with the user performance, such as tactility and dexterity as
seen in this chapter and with previous studies (70, 72, 99). The sizing of gloves was highlighted as a
concern in Chapter 3, with 62% of the participants indicating that the size of gloves they routinely
wear do not properly fit. By virtue of the formers mimicking the hands, the sizes must be based on
the anthropomorphic sizes of the hands of a general population. However, no information can be
found on the sizing regarding former manufacturing, and it is difficult to ascertain how these sizes
have been developed and established worldwide. Given some of the variations in size and how these
relate to the populations using the work in both this chapter, and in Chapters 4 and 5, it is clear to
see why participants who responded to the questionnaire in Chapter 3 stated that they believe they
are ‘between’ the glove sizes available. This was more prevalent in the NBR gloves. Although, more
users stated they wore NBR, the perception of NBR being ‘between sizes’ could be down to the
stiffness, the gloves not conforming to the hand, and having a ‘looser’ feel as indicated by Ooka and
Morimoto (227). As with much of the PPE, it is highly likely that the formers existing today are based
on the producing gloves fit for a male population. This is a timely issue, with the Royal College of
Nursing stating the problem of a one-size fits all sizing system is problematic for female nursing staff
(229). This problem has also been highlighted as more PPE is required, where it may have not been
use previously, over safety concerns regarding the covid-19 pandemic (177).
Anthropomorphic data, over time, has shown that there are clear and distinct differences
between hand sizes between men and women (230). Furthermore, hand sizes have been shown to
variate throughout different races (231). It is clear that the gloves manufactured today are not the
‘one size fits all’ that they perhaps were when glove manufacturing became more prevalent.
Although, it is appreciated how difficult it would be, from a manufacturing point of view, to
differentiate and create different sizes for different populations. On the other hand, a more specific
sizing does exist for the use of surgical gloves (99). Data is available that strongly indicates that glove
sizing requires a lot more research and changes should be made to ensure the safety of users, and to
not adversely affect performance. If glove sizes cannot be accurately ascertained by glove users,
there is a potential for diminished performance with regards to dexterous tasks (70, 99).
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6.6 Conclusions
Figure 6.23 summarises the findings in this chapter by showing the effects of stiffness on the
measured performances and ranks the gloves by their effects on dexterity.
Gloves ranked by user Decreased

dexterity friction
1. NRL (10% filler)
2. NBR 6348 Stiffer gloves Restricted Decreased
3. NBR 6329 movement dexterity
4. NRL
5. NBR 6311
6. PVC
Figure 6.23. Summary of chapter findings, showing the effects of the different materials on dexterity.
NRL with filler offers better dexterity, due to less restricted movement.
The findings of this chapter are:

• Dexterity of the participants was affected by the examination gloves used in this study, and
the differences in properties between gloves play an important role in both the friction and
dexterity of the gloves. The work conducted also highlights that gloves between studies
cannot be accurately compared, as previous studies looking at dexterity with different gloves
will have fundamental differences in their physical properties. In this study different grades
of NBR have different properties, leading to a difference in overall dexterity amongst the
glove users.
• The fundamental causes for differences that are apparent in studies of this nature are not
well understood. This study finds strong correlations between the glove stiffness and the
performance, which strongly indicates that a stiffer glove (such as the PVC) adversely affects
performance. This is hypothesised to restrict movement around the fingers, which decreases
dexterity. The stiffer gloves in this study were shown to reduce the dexterity of the
participants, whereas the less stiff gloves showed to increase the participants dexterity.
Further work assessing why, and how, medical gloves affect dexterity is pertinent to the
understanding of how to overcome issues whereby gloves decreased dexterity.
Understanding the parameters which may affect the gloves will allow the manufacturers to
understand and predict how newer glove materials may affect dexterity.
• Gloves decrease the frictional properties when compared to skin. The frictional properties
are found to be much lower for the stiffer gloves, due to behaviour of asperity contact.
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However, little correlation was noted between performance and the friction coefficients of
each glove.
• The sizing of gloves needs to be reviewed in accordance with the general population.
Although the gloves in this study were chosen as participants ‘best-fit’ there were clear
discrepancies in the fit between both participants and the gloves. Issues were also found in
previous chapters regarding the fit of gloves which further highlights this issue.
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Chapter Seven: Effects of contamination on glove friction
Having determined the requirement for the knowledge about the physical and chemical properties of
the materials, it is clear gloves need testing in the conditions they will be used in (6, 172, 232). New
industry standard testing can be difficult to implement. However, adapting existing tests to make
them more replicable of the conditions glove are used in, is easier to execute. Much of the work
carried out on friction has been previously discussed in Chapter 6. However, in the literature review
conducted in Chapter 2, it was shown that the reason gloves are donned is neglected from these
tests (6). That is, to protect the hands from contamination. Therefore, frictional properties may be
affected by this contamination, which in turn, could have an effect on performance. Only two papers
were found incorporating contaminants; water (114) and blood (116). This chapter of the thesis
focuses on that contamination, exploring how gloves may be affected in terms of friction when
exposed to a variety of substances. The frictional implications will then be discussed in terms of how
they affect dexterity and sensitivity in a later chapter (Chapter 8).
7.1 Introduction
Potentially, gloves are exposed to contaminants every time they are donned, hence the reason for
using them. Many of these contaminants have been discussed in Chapter 3, where it was discovered
that bodily fluids make up the majority of contaminant sources. However, the main respondents of
the questionnaire were from medical and clinical fields, thus the answers regarding bodily fluids are
to be expected. Blood was shown to be the most common contaminant for medical gloves. However
that has not been used in this chapter. This was due to reasons regarding quantity and stability over
the course of the tests. Nevertheless, blood was used in other tests and is discussed later in Chapter
9.
Other than blood, the most common fluids in contact were reportedly watery solutions such
as urine, sweat, water and liquid drugs. Medical disinfectants were also indicated to contaminate
gloves frequently. Combined, mucus and saliva make up the second (next to blood) most common
contact contaminant. A major protein constituent of these two fluids is mucin. Mucin is a central
component of mucus, found in saliva, nasal mucus, and the linings of the respiratory, urinogenital,
and gastrointestinal tracts (233). Composed of long peptide chains, mucins are of a characteristically
high molecular mass owing to the abundance of hydrophilic carbohydrate side chains that span off
the central protein (234). Due to this size, and hydrophilicity of the carbohydrates, charge repulsion
enables the mucin protein to entangle and form muco-adhesive gels. When the water evaporates
from the mucin gel, a thin muco-adhesive film is left behind, which can act as a tribo-film (235, 236).
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Mucin was chosen due to the abundance in the body, making it a likely source of contamination for
medical gloves (233).
7.2 Aim and scope

Analysing the friction present between tools and glove surfaces is key for the assessment of medical
gloves. Examination gloves need to retain a certain amount of friction for the user to be able to
precisely hold equipment, but not have too much friction as to make it difficult to manipulate and
hinder their dexterity. In this chapter, the frictional properties of NRL and NBR examination gloves
will be investigated. This includes assessing how the frictional properties change in response to
contamination. The questionnaire results in Chapter 3 revealed that, other than blood, common
contaminants are solvents, proteins, watery liquids, and powders. Thus, the contaminants used are
centred around substances with these properties to assess how they affect the frictional properties
of gloves with different tools used in clinical practice.
7.3 Materials and Methodology

7.3.1 Glove Material Selection and characterisation
Glove selection
The gloves used in this study were NRL gloves branded ‘Safe Touch’, purchased commercially, and
carboxylated NBR gloves, which were obtained from Synthomer. Both sets of gloves were powder
free and chlorinated. Other than the core material (acrylonitrile butadiene and natural latex), the
chemistry of the glove films was not able to be determined, as detailed information regarding
manufacturing was not available. Thickness of the gloves was measured at the palm and fingertips
using a micrometer (Mitutoyo, quickmini ±0.01 mm), and the gloves were found to be of a similar
thickness (NBR= 0.106 (±0.006) mm; NRL= 0.114 (±0.007) mm).
Surface roughness
Surface roughness was measured using the Alicona microscope (InfiniteFocusSL), as in Chapter 5.
Two samples of each glove were obtained from the fingers (4.0 × 4.0 cm) and two scans (1.5 × 1.5
cm) were made of each surface, with a 5x objective lens with magnification between -5.47 – 17.11x,
a lateral resolution of 3.71 µm, and a vertical resolution of 900 nm. Problems occurred with the
scanning of the NRL glove due to the colour and translucency of the material, a problem which is
noted in Chapters 4 and 6 with the NRL and vinyl gloves. The instrument could not scan small
sections of the NRL gloves, leading to small holes in the images produced; thus, a full surface area
measurement of scanned samples was not obtainable. Roughness was measured using an averaged
surface roughness (Sa) of a 0.5 × 0.5 cm portion of each scan.
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Atomic Force Microscopy
To assess the topography of the gloves in greater detail, atomic force microscopy (AFM) was used. One
5 × 5 mm section was cut off of three finger sections of each glove and mounted onto the AFM plate
(6 samples in total). The fingers of the gloves were used for this study to assess the surface topography,
as this is where the friction is most pertinent. The gloves were cleaned by the application of nitrogen
gas being blown onto the surface. This removed loose contaminants that may be present on the
surface of the material. AFM measurements were performed using a Bruker AFM (800 Multimode).
Scans were completed using the dual pass method, whereby the scanning cantilever probe passes over
the surface, taking topographical information and allowing phase images to be taken. Tapping mode
was used to obtain height, phase, and amplitude measurements at ambient temperature with a dual-
scanning rate of 4 and 12 Hz. In tapping mode, the cantilever oscillates up and down near the sample
surface via a piezo element. The tip of the cantilever will interact with the surface of the glove film via
electrostatic forces, Van der Waals bonds and dipole-dipole interaction. This causes the cantilever to
change in oscillation frequency the closer the tip is drawn to the sample (237). Thus, the image
produced is provided by the force of the interactions with the sample surface. Three different 2 × 2
µm areas of each glove sample were analysed. The inside of both of the gloves were also analysed for
any similarities to the outer. As the gloves are affixed with a low-tack adhesive to the AFM instrument,
the inner and outer surfaces are from different locations of the glove, and not the same section flipped
over, as this may have incurred some contamination. Each area analysed was further zoomed in and
analysed at 100 nm for further topographical information. Sample data and roughness measurements
were processed using Gwyddion imaging software.
7.3.2 Contaminant selection and characterisation
Six contaminants were selected for this study, based on responses regarding common contaminants
in Chapter 3. Whilst most of the contaminants suggested originate from the body, there are some
which were shown to be from different origins (e.g. solvents, cleaning, oils). The contaminants
selected here were chosen based on their likeness to bodily fluids, availability, ease of storage and
safety of disposal. In addition to this, contaminants were selected based on their differences in
properties, to allow assessment of how glove friction may be affected by the differences in behaviour
and interaction. The fluids selected are based across two major professions: forensic and clinical.
However some of these contaminants can be applied to multiple professions where gloves are used.
A mixture of the individual contaminants was also included. This was to mimic conditions
encountered when in gloves are in use, whereby contaminants may mix together, and to understand
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how mixtures would affect the tribology of gloves (e.g. different affinity of components for the
gloves). The contaminants are shown in Table 7.1.
Table 7.1. Contaminants selected for friction assessment.

Contaminant Constituent Appearance Selection rational
Ethanol ≥99.8% Comes into contact with the
absolute with 2% gloves when cleaning (such as
Alcohol Clear, watery liquid
chlorhexidine cleaning skin) and sterilising
disinfectant equipment (238)
Globular protein, which is the
major component of mucus, saliva
Porcine gastric
and found lining organs in the
mucin protein Globular liquid
body. Mucus/saliva was said to be
(PGM, Type II, Colloidal proteins
Mucin a common-contact contaminant in
unpurified). suspended in
Chapter 3. The solutions display a
[10 mg/ml] solution solution
non-Newtonian behaviour and
made with DI water
viscosity reduces in response to
shear rate increase (235)
Constituent of fats, which can be
found in the body. Questionnaire
Viscous, greasy showed contaminants of steroidal
Oil Triglyceride fat
liquid oil suspensions is known to
contaminate gloves when
discussed in Chapter 3.
Magnesium Silicate Powder residues are common
(talc) from tablet handling in the
Powder White, fine powder
(Johnson and medical field and are frequently
Johnson) encountered in the forensic sector
Commonly many contaminants
Water DI water Clear liquid from the body are watery in
nature (e.g. urine).
5ml Ethanol, Mucin
Colloidal liquid,
5ml, Vegetable oil A mixture of the individual
mucin suspended.
Mixture 5ml, Baby Powder contaminants is included to assess
Oil and powder on
0.5g, and 25ml differences in glove behaviour.
liquid surface
water
Viscosity
To measure the viscosity (η), 10 ml of each solution was measured with an AND vibro-viscometer
(SV-1A, ±0.01 mPa s.). Each solution was measured three times to obtain an average. Solutions were
shaken for 2 minutes before filling the sample well to disperse any colloidal suspensions and induce
homogeneity. Samples were measured at room temperature (23.9-24.9°C), with the exception of
mucin, which was heated to physiological temperature. As this is the only fluid being used which
originates from a body, it was thought a more realistic view of the effects of the protein interaction
was to heat it to physiological temperature (36-37°C).
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Contact angles
Contact angles were measured using the sessile drop method used in Chapter 4 and 5 (see Section
4.3.1). Samples were measured 5 times with the solutions at room temperature (24-27°C), with the
exception of mucin which was heated to 37°C with a water bath. In Chapter 4, it was shown that the
contact angle was not affected by the strain of the material. Thus, the gloves in this chapter were
studied in an unstrained condition using the stretching device shown in Section 4.3.1 (Figure 4.5).
Contact angles were determined to assess the initial interaction with the gloves and assess the
wettability of the different surfaces.
7.3.3 Tool selection
The tools and patterns used in this study are shown in Table 7.2. Tools were provided by The
University of Sheffield Dental School and were selected based on the difference in tool patterns on
commonly used equipment. Measurements of the manufactured patterns were made using a scaled
compound microscope (Kern, KEOBS-101) and a ruler. The steel strip (tool 7) is the same strip used in
Chapter 6, where it was used to compare frictional performance to dexterity with pegboard pins.
Where the roughness (Ra) is reported, the measurement was recorded using a surface profilometer
(Mitutoyo, SJ400) over a 2.5 (±0.001) cm section with a measuring speed of 1 mm/s and a force of 0.75
mN. This was repeated three times along the surface.
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Table 7.2. Tools used for analysis of frictional properties. Wavelength refers to the distance between
repeating parts of the pattern.
Pattern Pattern Wave-

Tool Material Image shape depth length
(mm) (mm)
1 Metal 0.02 1.0
2 Metal 0.08 2.8
Smooth
3 Ceramic
Ra = 0.08 µm
4 Metal 0.03 0.02
5 Metal 0.04 1.0
6 Plastic 0.05 3.0
Smooth
Smooth Metal
Ra = 0.11 µm
7.3.4 Friction methodology

The methodology for the friction analysis follows the same as described out in the previous chapters
but follows more closely to the friction tests designed in Chapter 6 (see Section 6.3.5). The tools were
alternately fixed to the AMTI force plate and secured with tape to ensure there was no relative
movement, as in Figure 7.1. Further tape was placed over the end of the tools to further secure the
tools to the plate and cover the sharp edges. The angle between the finger and the surface was kept
at approximately 40° in order to measure just the gloved finger pad friction. After holding the finger
in place on the tools for 2-3 seconds, the finger pad was dragged along the plate to cause a sliding
action (at around 0.6 mm/s). As in Chapter 6, only static friction was used for this study, as this is
friction most relevant to holding tools of this nature (114, 116). Gloves were donned on the right
hand of the sole participant (male, aged 28), and the tools/force plate were cleaned with
acetone/water and dried before repeating with another contaminant. The gloves were also changed
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between contaminants to avoid cross contamination. The friction tests were carried out with both
gloves in the dry condition, and with gloves exposed to each of the six contaminants (14 tests in
total).
Direction of finger travel
Figure 7.1. Tool 2 affixed to the AMTI force plate.
Load selection
Force selection was chosen based on the loads used in Chapter 6 for consistency. These loads were
selected to replicate grip forces based on literature, as discussed in Chapter 6. The target loads
selected in this study are 1, 2, 3, 4 and 5 N. A range of loads allows for the understanding of how the
contaminants are changing friction with different grip force, as well as how the contaminants may
change in behaviour over the load range. Tests were repeated three times at each load to obtain an
average.
7.3.5 Contaminant application

Fluid contaminants were applied to the glove by dipping the gloved index finger into the fluid
contaminants. The solution covered the finger up to the proximal-intermediate interphalangeal joint
(around 5 cm up the finger, Figure 7.2) and was held for 10 seconds. This was to ensure coverage of
the finger pad and allow interaction between the fluid and the glove film. The finger was removed,
and excess fluid was shaken off of the finger before placing onto the tool.
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Contaminant
Length of contamination
Proximal-intermediate interphalangeal joint Radius

(r)
Figure 7.2. Location of contaminant on finger (shown in green) to the interphalangeal joint of the
index finger.
All contaminants were tested at room temperature (22-25°C,) with the exception of mucin, which
was heated to 37 (±1.5) °C via a water bath to achieve physiological temperature, as previously
discussed. When the test was being conducted, the temperature of the mucin was monitored using
an infrared thermometer (Raytek, RSCMTFSU ±0.5°C) from removal of the water bath to application
of the tool. It was found the mucin temperature dropped 3-5°C to around (32-33°C). Initially, the
mucin was going to be heated to 40-42°C in order to account for this drop in temperature. However,
proteins are intricate, changing their shape and ultimately their behaviour depending on the
temperature (233, 234). Changing the temperature higher could have caused some denaturation to
the proteins, changing their interaction with the gloves, and lead to erroneous conclusions of their
effects. Therefore, the testing was continued by initially heating the mucin to 37°C. To apply the
powder, the finger pad was place in the powder, patted, and then rolled around to ensure coverage,
as shown in Figure 7.3.
Figure 7.3. Powder application to the finger pad.
Contaminant mass and film thickness
To determine the amount of contaminant on each glove, the gloves were weighed using an analytical
balance (Ohaus, PR124 ±0.0001 g), before and after application of contaminants. This test was
conducted as a separate study to determine the differences in contaminant deposition onto the
174
gloves and followed the same application procedure described. This was conducted three times with
each contaminant to obtain an average.
The thickness of the deposited contaminants has been calculated to further highlight
differences in the liquid contaminants surrounding the gloves. Whilst many instrumental methods
exist to assess film formation thickness, the precision of these instruments are used to measure
extremely thin films deposited onto the surfaces using controlled synthesis of materials (239, 240).
Given the procedure used to deposit the contaminants, and the evaporation rate of the
contaminants (such as alcohol), it was thought that instrumental analysis was not applicable. Thus,
analysis has been conducted using an estimated film thickness. The estimated thickness (t) of each
film was calculated using the density (ρ) and the mass (m) transfer of the contaminants to the
calculated surface area (a) of the glove (239, 241). Estimated film thickness was calculated using
Equation 7.1.
𝑚
𝑡=
𝑎 × 𝜌
Equation 7.1
Density (ρ) was calculated by pipetting (Scorex, Acura ±5 µL) 1 ml of each sample to a pre-weighed
Eppendorf tube. The density was then calculated using Equation 7.2.
𝑚
𝜌=
𝑉
Equation 7.2
where m is mass of solution and V is volume. The area with which the finger was contaminated (A)
was calculated using the formula for a flat ended cylinder (with only the area of one flat end
calculated), by using Equation 7.3.
𝐴 = (2𝜋 𝑟 𝑙) + (𝜋 𝑟 2 )
Equation 7.3
where r = radius and l = length, depicted in Figure 7.3. It is appreciated this method of determining
film thickness has some shortcomings, as it assumes that the shape, and that the film is even and
uniform along the entire surface, and the same volume of liquid is on the finger in every friction test.
However, together with the calculations of how much of the contaminant is deposited onto the
finger, these calculations highlight the differences in interaction between the glove films.
175
7.3.6 FTIR
FTIR was conducted on different regions of the gloves following the discovery of an adsorbed
substance on the surface by the AFM. FTIR analysis was conducted using a Brucker ATR-FTIR
instrument. Each sample was scanned 26 times in the 550-4000 cm-1 region with a resolution of 4 cm-
1
. FTIR was conducted on both of the gloves in 3 separate regions.
7.3.7 Data and statistical analysis
Data was processed as in previous chapters, calculating the resultant horizontal force to account to
for misalignment when sliding the finger down the tools (Equation 4.2) and then the friction
coefficients calculated via Equation 4.3. The data was processed to a power fit law, also described in
Chapter 4 (Equation 4.4). Data was analysed using a two-tailed paired t-test to test for statistical
significance. As the aim of this study is to evaluate whether the glove friction is affected by each
contaminant, paired (two-tailed) t-tests were performed to compare the frictional of differences
between the contaminant and the dry gloves. In conjunction with this, NBR and NRL gloves were also
checked for differences, in order to establish any behavioural variations between the two gloves
when contaminated. The alpha value for determining whether a result is statistically significant is set
at α=0.05. Therefore, a probability of difference value (p) should be less than 0.05 to be defined as
statistically significant.
7.4 Results
7.4.1 Surface roughness and AFM of gloves
Three images are shown for each AFM sample, which represent the different types of scanning. In the
height images, the brighter areas denote higher sections of the sample. In amplitude error, the brighter
areas indicate a greater amplitude error, and in the phase mode, a brighter area indicates less viscous
portions of the sample.
Figure 7.4 (a-c) shows a selection of the height, amplitude error and phase measurements of
the outer surface of the NBR gloves and NRL is shown in Figure 7.5 (a-c). The results of the topography
(height) show smaller clusters of the NBR compounds, whereas NRL shows larger clusters with bigger
gaps between the groups of latex rubber. The gaps are possibly due to the differences in the patterns
of the gloves, created during the manufacturing process. The NBR has a fixed random bump pattern
manufactured at the fingertip, similar to the NBR gloves described in Chapter 6. The NRL gloves have
a textured surface all the way around the glove, which is not too dissimilar from the NBR, also noted
in Chapter 6.
176
a) b)
c)
Figure 7.4 (a-c). AFM images of NBR glove showing height (a), amplitude error (b), and phase (c)
images.
a) b)
c)
Figure 7.5 (a-c). AFM images of NRL glove showing height (a), amplitude error (b), and phase (c)
images.
177
Adsorption
Where the interaction between the cantilever and the surface of the sample changes, there will be a
change in the resonance frequency of the AFM instrument. For forces where more attraction is
present, the frequency will be lower. For the forces where more repulsion is present, the frequency
will be higher. Thus, the phase image allows for visualisation of the changes in properties of the
material. Due to the nature of the attraction-repulsion forces of the AFM cantilever, any material
property will show as a difference in the image (dissipation, adsorption, viscoelasticity, stiffness,
adhesion) (242). Therefore, the phase images must be read with some caution (243). Nevertheless, a
noticeable feature on both the NBR (Figure 7.6) and NRL (Figure 7.7) AFM scans was the presence of
a possible adsorbed layer on the sample surface. Where the topographical image (height) shows a
lighter section (higher) and the phase image shows a darker area (lower) this indicates the presence
of liquid or gas adsorbed onto the material (244). In the NBR particularly, there are areas where
‘smearing’ is present (as is visible in Figure 7.6 b). Therefore, it was thought this was a result of
contamination. As stated in the method, three samples of each glove were analysed, and this
smearing and adsorption was noted in all three. Gloves were cleaned with nitrogen gas to remove
any contaminants prior to analysis; however, this does not remove the presence of contaminants
from handling, although gloves were worn. Figures 7.8 (NBR) and 7.9 (NRL) show the inner surface of
the gloves. These also show the difference in phases seen on the outer gloves. In the NBR, this
possible adsorption appears more in localised areas, rather than smeared as in Figure 7.6. The NRL,
however, shows some similarities to the outer surface, however there are smaller, more frequent
lighter areas (Figure 7.9).
178
a) b)
Figure 7.6. Height (a) and phase (b) images of the outer side of the NBR glove section showing the
possible adsorption onto surface. Area of smearing has been highlighted.
a) b)
Figure 7.7. Height (a) and phase (b) images of the outer side of the NRL glove section showing the
possible adsorption onto surface.
a) b)
Figure 7.8. Height (a) and phase (b) images of the inner side of the NBR glove section showing the
a) b)
Figure 7.9. Height (a) and phase (b) images of the inner side of the NRL glove section showing the
179
Adsorption identification
Visual analysis
Upon visual examination of the gloves, it can be seen that the gloves are not homogenous in colour.
In essence, the gloves are not one solid shade of colour and show regions which are darker/lighter. In
some cases, the differences are visible as dried drips. Figure 7.10 shows areas (around 25 cm2) of the
gloves where there are differences in light transparency when held up against a light source. The
images have been saturated and overexposed in order to highlight these differences (NBR: +40
brightness, -40 contrast and +200% saturation; NRL: +30 brightness, -20 contrast and +400%
saturation). Images are shown which are similar to the AFM phase mode in terms of contrast, clearly
indicating the presence of different adsorbed substances onto the surface.
a) b)
Figure 7.10. Difference in NBR and NRL films when exposed to light. a) NBR, colour correction +40
brightness, -40 contrast and +200% saturation and b) NRL, +30 brightness, -20 contrast and +400%
saturation.
FTIR
In an attempt to identify the suspected adsorbed substance, FTIR was conducted on the gloves in 3
separate regions. The FTIR analysis was targeted on different places of the glove, ensuring the visible
‘drips’ noted were captured in the scans. No measurable variations are seen in the spectra (Figure
7.11).
180
Figure 7.11. FTIR of NRL and NBR outer layers assessing for differences between scans.
Localised roughness
The AFM shows clusters of the core materials, with deep grooves between them. These grooves on
the NBR are less deep, with an average depth of 60.71 (±13.43) nm, whereas NRL has grooves with
depths of 151.88 (±4.78) nm. The clusters of materials were also scanned to assess the localised
roughness. Figure 7.12 shows a typical roughness of the NBR sample (Ra=6.89 (±0.13) nm) and Figure
7.13 shows a profile of the NRL roughness (Ra=10.72 (±1.19) nm). It is important to note, this is only
a 2 µm section shown. Therefore, the roughness differences shown are only on a small scale. Of the
three scans taken, roughness measurements were taken on the 2 µm samples only, as these gave the
clearest images for measurements.
12.0
7.0
Height (nm)
2.0
-3.0
-8.0
-13.0
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00
Length (nm)
Figure 7.12. AFM roughness profile of NBR glove section
181
12.0
7.0
Height (nm)
a)2.0Sa 1.83 µm
-3.0
-8.0
-13.0
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00
Length (nm)
Figure 7.13. AFM roughness profile NRL glove section.
Surface roughness
The surface roughness scans using the 3D measurement instrument shows the average film
roughness on a greater scale. Both of the gloves are shown to have similar surface roughness. NBR
has a Sa of 1.83 (±0.27) µm, whereas NRL is slightly rougher with a Sa of 1.90 (±0.25) µm. Samples of
the scans are shown in Figure 7.14. Although the gloves show similar Sa, the patterns on the glove
are visually different. The NRL has a more concave nature of grooves, whereas the NBR appears more
textured.
a) Sa 1.83 µm b) Sa 1.90 µm
Figure 7.14. Surface roughness (Sa) of NRL (a) and NBR (b) gloves.
182
7.4.2 Contaminant characterisation
The viscosities of the contaminants can be found in Table 7.3. The lower end of the viscosity ranges
from very low at 0.90 mPa-s with water to 7.25 mPa-s with the mixture solution. The highest noted
viscosity is the oil at 70.10 mPa-s. Also, in Table 7.3 is the estimated film thickness. The NBR material
is most likely to allow a thicker film to develop (with the exception of the alcohol, NBR t=2.40 µm;
NRL t= 2.59 µm). This is also indicated from the results of the mass transfer used to calculate the film
thickness, which are shown in Figure 7.15. In the mass transfer, it is shown that more substance is
deposited on the NBR material, indicating higher affinity for the material over the NRL. All data was
found to be within a normal distribution via the Shapiro-Wilk test for normality (192). The results
show that the oil gives the greatest mass transfer, and the greatest film thickness (NBR mass= 0.14
(±0.006) g, t=5.74 µm; NRL mass=0.12 g (±0.005), t=5.00 µm). With exception of the powder, the
alcohol shows the lowest transfer of substance for both NBR and NRL gloves. This also leads to the
lowest estimated film thickness.
Table 7.3. Viscosity (η), density (ρ), and estimated film thickness (t) of fluid contaminants.
t
η ρ
Contaminant (µm)
(mPa-s) (kg/M3)
NBR NRL
1.02 814.69
Alcohol 2.40 2.59
(±0.01) (±0.05)
3.13 1085.25
Mucin 4.40 3.64
(±0.05) (±1.09)
70.10 929.95
Oil 5.74 5.00
(±0.01) (±0.06)
0.90 984.32
Water 2.84 2.76
(±0.01) (±0.06)
7.25 1007.91
Mixture 4.82 3.43
(±0.05) (±0.05)
183
0.16
0.14
Mass (g) 0.12
0.1
0.08
NBR
0.06
NRL
0.04
0.02
0
Alcohol Mucin Oil Water Mixture Powder
Contaminant
Figure 7.15. Weight of contaminants deposited onto the gloves. Error bars indicate standard
deviation.
Contact angle
Figure 7.16 shows the results of the contact angles of the fluid contaminants with both glove films.
With the exception of alcohol, all contaminants show a high surface wetting with NBR (low contact
angle) and a low surface wetting (high contact angle) with NRL. The alcohol, however, shows to have
a similar, low contact angle and high surface wetting of both samples (NBR= 21.67°, ±3.06; NRL=
22.33°, ±5.13). These were shown to be statistically similar following a paired two tailed t-test (t(2)=-
0.193, p=.886).
140
120
100
Contact angle (°)
80
60 NBR
NRL
40
20
0
Alcohol Mucin Oil Water Mixture
Contaminant
Figure 7.16. Contact angles of contaminants on the NBR and NRL material. Error bars indicate
standard deviation
184
7.4.3 Friction
Over the load range it was discovered there was little difference between the coefficient of friction
(CoF) at the minimum and maximum normal force applied for many of the contaminants, most
notably in the NBR gloves. For this reason, and for simplicity in data presentation, only the CoFs at
the minimum (~1 N) and maximum (~5 N) normal forces are displayed. CoFs at each load for each
tool and contaminant can be found in the appendix, Section D.
NBR
In all of the tests conducted, the friction was found to increase with an increasing normal force. The
CoF at minimum and maximum normal force for all of the tools and contaminants with NBR are
shown in Figure 7.17. The t-test results comparing contaminant to the dry CoF are shown in Table
7.4. With the exception of tools 5 and 7, there is little change exhibited between the dry condition
with some of the contaminants. However, there is a noticeable increase in CoF when compared to
the contaminated friction. Statistical significance is shown between the dry condition and all other
conditions in tools 5, 6, and 7 (p<.05). In tools 1-5 the water produces the lowest CoF, with the
lowest being observed in tool 5 at the maximum normal force (µ= 0.19 ± 0.03), however there is little
overall trend in which contaminant produces the greatest friction. Tools 1-4 show a more clustered
variation in the results between the contaminants, indicating little difference in friction behaviour
with notable exceptions (such as the mucin in tool 1), however there are many significant differences
seen from the dry condition (p<.05). There is no contaminant which shows consistently significant
differences from the dry condition. However, the greatest differences between the dry gloves and
the contaminants are shown in tools 5 and 7, where contaminants are shown to greatly decrease the
frictional properties of the gloves (p<.05). This is also observable in tools 4 and 6, but to a lesser
extent. In general, the CoFs exhibit slight changes over the increasing loads, however these are not
greatly different in many of the cases.
185
Dry Alcohol Mix Mucin Oil Powder Water
2.2
1.8
1.6
1.4
1.2
CoF
0.8
0.6
0.4
0.2
0
Min Max Min Max Min Max Min Max Min Max Min Max Min Max
Tool 1 Tool 2 Tool 3 Tool 4 Tool 5 Tool 6 Tool 7
Normal Force
Figure 7.17. CoFs at the minimum (min) and maximum (max) normal forces applied with the NBR gloves in dry and contaminated conditions with each tool. Error
bars denote standard error in the obtained CoFs.
186
Table 7.4. Results of t-tests comparing CoFs of contaminants to the dry NBR glove at the minimum (~1 N) and maximum (~5 N) normal forces.
Normal
Contaminant Tool 1 Tool 2 Tool 3 Tool 4 Tool 5 Tool 6 Tool 7
Force
t(2)=6.288 t(2)=-1.172 t(2)=-2.345 t(2)=-7.620 t(2)=-21.357 t(2)=-19.451 t(2)=20.667
min
p=.002* p=.153 p=.039* p=.001* p=<.001* p=<.001* p=<.001*
Alcohol
t(2)=-1.546 t(2)=-8.255 t(2)=8.877 t(2)=1.228 t(2)=35.554 t(2)=-14.569 t(2)=23.305
max
p=.099 p=.001* p=.023* p=.143 p=<.001* p=<.001* p=<.001*
t(2)=-48.932 t(2)=-1.665 t(2)=1.600 t(2)=24.419 t(2)=26.685 t(2)=-3.089 t(2)=11.895
min
p=<.001* p=.086 p=.092 p=<.001* p=<.001* p=<.018* p=<.001*
Mucin
t(2)=-64.383 t(2)=-0.930 t(2)=-1.380 t(2)=4.274 t(2)=36.518 t(2)=-2.345 t(2)=11.771
max
p=<.001* p=.203 p=.120 p=.006* p=<.001* p=<.039* p=<.001*
t(2)=-5.265 t(2)=-2.334 t(2)=3.302 t(2)=9.67 t(2)=16.406 t(2)=-6.513 t(2)=25.134
min
p=.003* p=.040* p=.015* p=<.001* p=<.001* p=<.001* p=<.001*
Oil
t(2)=-26.169 t(2)=26.144 t(2)=1.439 t(2)=1.094 t(2)=22.458 t(2)=-13.795 t(2)=14.983
max
p=<.001* p=<.001* p=<.001* p=.168 p=<.001* p=<.001* p=<.001*
t(2)=-2.604 t(2)=1.550 t(2)=3.491 t(2)=5.100 t(2)=11.930 t(2)=17.413 t(2)=33.788
min
p=.030* p=.098 p=.013* p=<.001* p=<.001* p=<.001* p=<.001*
Powder
t(2)=0.751 t(2)=19.922 t(2)=31.616 t(2)=3.715 t(2)=29.297 t(2)=8.317 t(2)=27.290
max
p=.247 p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
t(2)=0.899 t(2)=2.787 t(2)=11.284 t(2)=15.145 t(2)=27.693 t(2)=3.030 t(2)=33.788
min
p=.210 p=.025* p=<.001* p=<.001* p=<.001* p=<.019* p=<.001*
Water
t(2)=11.224 t(2)=1.342 t(2)=15.415 t(2)=4.025 t(2)=72.825 t(2)=8.317 t(2)=20.238
max
p=<.001* p=.125 p=<.001* p=.008* p=<.001* p=<.002* p=<.001*
t(2)=-2.632 t(2)=-1.558 t(2)=10.349 t(2)=11.791 t(2)=21.584 t(2)=17.193 t(2)=21.220
min
p=.029* p=.097 p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
Mixture
t(2)=-9.898 t(2)=-7.341 t(2)=10.276 t(2)=3.360 t(2)=38.824 t(2)=-4.825 t(2)=25.357
max
p=<.001* p=.001* p=<.001* p=.014* p=<.001* p=<.004* p=<.001*
*denotes statistical significance p<.05
187
NRL
In all cases, with all contaminants and tools, the friction force increased with an increase in load with
both gloves. The CoFs at the minimum and maximum normal force applied for all of the tools with NRL
are shown in Figure 7.18. With the exception of tool 6, the dry condition has a greater CoF than when
contaminants are added. Large variations in CoFs are observed with the dry conditions over the load
range. Tool 1 is the only tool were the CoF increases with the increasing load, whereas the CoF
decreases over the load range with the other tools. When contaminants are present, mucin induces
more friction than the other contaminants, with higher friction coefficients observed for tools 2, 4, 5
and 6. Water is also observed to have higher friction than the other contaminants in tool 1 and is
highest in tool 7 (µ at minimum normal force= 1.28 ±0.03; µ at maximum normal force= 1.31 ±0.03).
Water and mucin exhibit similar CoFs over the loads with tool 3, and both produce the highest friction
coefficients. Tools 3, 4 and 5 show small variations for the obtained CoFs, with similar ranges across
the contaminants (µ=0.46-0.18). The CoFs however, do show slight changes in behaviour, such as
water and mucin showing a decrease in CoF between minimum and maximum normal forces with tool
3, but increasing friction in tool 4 over the load range. In all of the tools used in this study, statistically
significant differences are exhibited between each contaminant and the dry glove (p<.001, Table 7.5).
Only one contaminant was found to be statistically similar to the dry condition is the water in Tool 6 at
both the maximum (dry µ=0.97 ±0.02; water µ=0.99 ±0.02) and minimum (dry µ=1.03 ±0.02; water
µ=0.97 ±0.05) normal forces. Mucin also shows similarities to the dry condition in tool 6 at the
minimum force (mucin µ=1.10 ±0.06; t(2)=-0.840, p=.224). Although no clear trends are observed,
there is a pattern of oil producing the lowest CoFs for each of the tools, and the mucin contaminant is
generally of greater friction in 5 of the 7 pattern textures.
188
Dry Alcohol Mix Mucin Oil Powder Water
2.2
1.8
1.6
1.4
1.2
CoF
0.8
0.6
0.4
0.2
0
Normal Force
Figure 7.18. CoFs at the minimum (min) and maximum (max) normal forces applied with the NRL gloves in dry and contaminated conditions with each tool. Error
bars denote standard error in the obtained CoFs.
189
Table 7.5. Results of t-tests comparing CoFs of contaminants to the dry NRL glove at the minimum (~1 N) and maximum (~5 N) normal forces.
Contaminant Normal Force Tool 1 Tool 2 Tool 3 Tool 4 Tool 5 Tool 6 Tool 7
t(2)=72.385 t(2)=17.959 t(2)=149.484 t(2)=31.998 t(2)=193.131 t(2)=9.203 t(2)=39.299
Min
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
Alcohol
t(2)=62.638 t(2)=20.115 t(2)=20.905 t(2)=63.515 t(2)=30.516 t(2)=8.546 t(2)=70.241
Max
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=.001* p=<.001*
t(2)=27.899 t(2)=16.961 t(2)=28.314 t(2)=32.050 t(2)=69.464 t(2)=-0.840 t(2)=39.768
Min
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=.224 p=<.001*
Mucin
t(2)=35.961 t(2)=17.488 t(2)=19.496 t(2)=61.744 t(2)=35.482 t(2)=-4.963 t(2)=33.903
Max
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=.004* p=<.001*
t(2)=76.008 t(2)=27.445 t(2)=170.868 t(2)=35.157 t(2)=188.489 t(2)=9.005 t(2)=87.840
Min
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
Oil
t(2)=92.196 t(2)=35.309 t(2)=20.495 t(2)=45.253 t(2)=34.512 t(2)=74.220 t(2)=103.418
Max
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
t(2)=45.321 t(2)=22.987 t(2)=64.026 t(2)=29.602 t(2)=177.797 t(2)=22.357 t(2)=71.882
Min
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
Powder
t(2)=77.302 t(2)=13.482 t(2)=20.276 t(2)=34.720 t(2)=27.804 t(2)=105.939 t(2)=334.923
Max
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
t(2)=17.081 t(2)=17.313 t(2)=58.469 t(2)=27.587 t(2)=48.554 t(2)=1.035 t(2)=28.949
Min
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=.180 p=<.001*
Water
t(2)=53.224 t(2)=24.225 t(2)=20.003 t(2)=56.984 t(2)=22.365 t(2)=-1.272 t(2)=11.282
Max
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=.136 p=<.001*
t(2)=29.370 t(2)=24.807 t(2)=28.314 t(2)=32.050 t(2)=69.464 t(2)=24.257 t(2)=82.262
Min
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
Mixture
t(2)=96.434 t(2)=32.020 t(2)=19.496 t(2)=61.744 t(2)=35.482 t(2)=97.908 t(2)=6.647
Max
p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001* p=<.001*
*denotes statistical significance p<.05
190
Material comparison
Figure 7.19 shows the CoF at minimum and maximum normal force for both NRL and NBR gloves with
contaminants (combined graphs of the above Figure 7.17 and 7.18). As can be see, there is little
similarity between the CoFs of the contaminants. In tool 1, the powder contaminant does produce
similar CoFs between the NBR (µ at minimum normal force= 0.37 ±0.04, µ at maximum normal force=
0.27 ±0.01) and the NRL (µ at minimum normal force= 0.39 ±0.01, µ at maximum normal force= 0.29
±0.01). The lowest overall CoF is observed with NRL and oil on the smooth steel (µ= 0.09 ±0.02). A
comparison of the averaged CoFs is presented in Table 7.6 along with statistical significance between
the two gloves highlighted via paired t-tests. There are no observed statistically significant differences
in tool 1 with the alcohol, mixture, mucin, and the powder at the minimum force. Indicating at a low
load there is no significant difference in friction between these contaminants on either of the gloves
(p>.05). The only occurrence of a contaminant not changing frictional properties between the two
gloves, at the minimum and maximum normal force, was with alcohol when applied to tool 2, and
powder applied to tool 1 (p>.05). As many of the comparisons show significant differences between
the gloves, it is highlighted that there are likely differences in the contaminant interaction with the
glove materials causing differences in frictional behaviour.
191
Dry NBR Alcohol NBR Mix NBR Mucin NBR Oil NBR Powder NBR Water NBR
Dry NRL Alcohol NRL Mix NRL Mucin NRL Oil NRL Powder NRL Water NRL
2.2
1.8
1.6
1.4
1.2
CoF
0.8
0.6
0.4
0.2
0
Normal Force
Figure 7.19. CoFs at the minimum (min) and maximum (max) normal forces applied both NBR and NRL gloves. NBR is represented by straight lines, whereas NRL is
represented by dashed lines. Error bars denote standard deviation in the obtained friction coefficients.
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Table 7.6. Average friction coefficient values obtained from each tool with the different contaminants used for the NRL and NBR gloves. Those highlighted in green
show statistically significant differences between the two glove materials at the retrospective force (p<.05), whereas those in blue do not show any statistically
significant differences between the two average friction coefficients (p>.05).
Friction Coefficient
Tool 1 Tool 2 Tool 3 Tool 4
Condition
Min force Max force Min force Max force Min force Max force Min force Max force
NBR NRL NBR NRL NBR NRL NBR NRL NBR NRL NBR NRL NBR NRL NBR NRL
Dry 0.26 1.23 0.26 1.47 0.51 1.71 0.43 1.12 0.57 1.78 0.46 1.56 0.47 1.62 0.48 0.99
Alcohol 0.24 0.18 0.28 0.24 0.55 0.58 0.56 0.61 0.59 0.39 0.41 0.2 0.39 0.32 0.43 0.28
Mix 0.31 0.32 0.35 0.14 0.46 0.43 0.51 0.41 0.42 0.33 0.38 0.24 0.27 0.28 0.34 0.21
Mucin 0.5 0.56 0.53 0.39 0.57 0.78 0.43 0.77 0.53 0.44 0.48 0.34 0.28 0.43 0.31 0.46
Oil 0.33 0.22 0.36 0.18 0.58 0.29 0.59 0.37 0.42 0.22 0.25 0.22 0.42 0.22 0.43 0.21
Powder 0.37 0.39 0.27 0.29 0.45 0.51 0.58 0.59 0.38 0.29 0.22 0.24 0.28 0.39 0.35 0.34
Water 0.22 0.61 0.21 0.57 0.37 0.71 0.40 0.58 0.37 0.45 0.23 0.26 0.28 0.39 0.33 0.4
Friction Coefficient
Tool 5 Tool 6 Tool 7
Condition
Min force Max force Min force Max force Min force Max force
NBR NRL NBR NRL NBR NRL NBR NRL NBR NRL NBR NRL
Dry 0.74 1.35 0.66 1.05 0.36 1.03 0.30 0.97 1.05 2.15 1.1 1.67
Alcohol 0.32 0.33 0.43 0.26 0.49 0.7 0.52 0.77 0.36 0.43 0.42 0.44
Mix 0.21 0.28 0.22 0.12 0.30 0.33 0.37 0.32 0.53 0.42 0.30 0.18
Mucin 0.24 0.47 0.40 0.54 0.46 1.1 0.33 1.03 0.72 0.97 0.79 0.67
Oil 0.34 0.22 0.31 0.18 0.63 0.68 0.53 0.29 0.25 0.09 0.28 0.09
Powder 0.35 0.29 0.26 0.32 0.16 0.36 0.21 0.32 0.31 0.29 0.33 0.21
Water 0.23 0.45 0.19 0.35 0.34 0.97 0.35 0.99 0.42 1.28 0.52 1.31
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7.5 Discussion
7.5.1 AFM and roughness profile
There are similarities between the NRL and NBR materials. However, on the nano scale, a great
difference in roughness is shown, with the NBR being half the roughness of the NRL. Between both
of the glove films, there are clusters of the core compounds present with grooves in between these
clusters. The grooves on the NBR are smaller and shallower than observed in the NRL. This clustering
and size difference between particles is to be expected due to the reported particle size of NBR
being smaller on average (0.1-1.0 µm) than the NRL material (0.3-2.0 µm) (14, 44, 45). It is possible
the gaps present are the edges of the raised bumps pattern on the NRL gloves; however, they were
present frequently throughout each scan. When looking at the roughness of the gloves on a greater
scale (using the optical microscopy) the gloves are shown to have similar surface roughnesses. Thus,
the frictional difference in the dry gloves is possibly a result of the material properties, as discussed
in Chapter 6.
Adsorption
Noticeably on both the NBR and NRL scans, there is the presence of an adsorbed substance onto the
films. The phase images of the NBR material are similar to images published by Zhao, Xiang, Tian, et
al. (245) who looked at NBR composites, and used AFM to find localised regions of different co-
polymers after dispersing in manufacturing. However, the images from Zhao et al. (245) are taken
from 0.5 × 0.5 nm areas, which are incredibly small areas. As multiple gloves were scanned, and they
all had the similar phase images, this study shows that there is likely to be an adsorbed layer on the
surface. This leads to the inference that this is a result of the post film manufacturing (leaching,
chlorination etc.) once the core film has been dipped. Therefore, it is reasonable to assume that the
chlorine has been adsorbed onto the surface, as discussed in depth in Chapter 5. When chlorinating
the gloves in industry, the gloves are also sometimes ‘double chlorinated’, exposing both the inside
and the outside to the chlorination treatment. In the NRL material, this reduces the amount of
extractable proteins, leading to a lower exposure to the latex protein which causes allergies (14).
Furthermore, tumble washing is a method of chlorinating gloves, which would expose both sides of
the gloves to the chlorine (51). However, it is well documented that the chlorination process
deteriorates the gloves, and the smoother surface on the outer side of the gloves can lead to
problems with gripping through the reduced surface roughness (16, 47, 51). As stated in the results,
due to the sensitivity of the phase imaging measuring different properties, these differences in the
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phase images could be due to mechanical properties, rather than chemical (e.g. slightly thicker
regions of the gloves).
As no measurable variations are seen in the spectra (Figure 7.11), this indicates that the adsorbed
substance is either:
• Inert to the glove (such as water used for washing after the chlorination step),
• In such a small quantity that it is immeasurable to the FTIR,
Or
• Not an adsorbed substance, but the film itself with varied, with inhomogeneous regions
throughout which affect the material properties in these localised regions.
The results seen in the NRL AFM scans are similar to those seen in Ho and Khew (56) who used AFM
to analyse the films at different stages of the vulcanisation process. Although phase images were not
obtained, the authors indicate that the differences in surface topography is likely to be due to the
diffusion of the vulcanising reagents. The authors suggest that pre-vulcanisation is good for cross-
linking of the polymers and forming a smooth film, where the traditional vulcanising method cause
uneven cross-linking. It is possible the AFM is measuring differences in the latex particle coalescence,
and that is what is visible on the films simply exposed to light (Figure 7.10). Differences in surface
chemistry could have a great influence on the contacting surfaces, however minor. Thus, there may
be stronger localised attractions in certain areas of the gloves, which could give rise to the variations
seen in the contact angle measurements and friction, which will ultimately affect the performance of
gloves, as seen in Chapter 6.
7.5.2 Friction and effects of tool patterns

A study conducted by Laroche et al. (114), looking at the effects of glove friction on different tool
patterns of a similar nature, found, on average, the friction of the NBR gloves was higher than the
NRL. However, in this study, the opposite is observed in most of the tools. The study by Laroche et
al. (114) only looked at the effects of water on the static friction, with no control (dry condition) and
looked at higher normal forces (40 N). Furthermore, the study does not state whether the gloves
were examination or surgical, which was indicated to be a factor in the frictional properties due to
the bulk material properties in Chapter 6. Anwer (116) showed that blood and blood-water mixtures
lowered friction with NRL gloves on a scalpel, which is observed with some of the contaminants in
this study with the scalpel. As blood was not used in this study, the results cannot be compared
directly, but will be discussions around blood friction can be found in Chapter 9.
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In this study, few trends are observed with the contaminants through the various tools,
although most differences are shown in the NRL gloves in dry condition and in smoother surfaces
when mucin is applied. It was hoped there would be more observable trends in behaviour with each
contaminant, in order to quantify how friction was affected in a consistent manner. This would
better inform glove manufacturers on how their materials were responding to certain contaminants,
allowing for a better targeted marketing with regards to frictional properties of gloves depending on
their use. However, great frictional differences are apparent when the NBR and NRL gloves are in
contact with different tool surfaces. Tool 2, with the annular deep ridged surface, produced a
greater CoF with the contaminants in both of the glove materials. This was expected due to the
deeper pattern (0.8mm) which will allow contaminants to fall into the gaps and prevent separation
of the glove-tool surface. Therefore, contact area would be increased between the gloves and the
metal. This is evidenced by the general increase in the CoF with both glove materials, except mucin
and water, in which the CoF decreased as the load increased. It is likely that the differences in
affinity for the materials leads to this increase in CoF, as well as the material behaviour, previously
discussed in Chapter 6. The NRL gloves display greater CoFs than the NBR gloves, on average. It is
also observed there is little change in CoF as the load increases with the dry NBR gloves, where NRL
has much greater CoF changes over the loads with each tool. However, friction does increase with
each load, but the friction is greater with the NRL material. In many of the gloves, it could be seen
that the NRL was stretching during the movement of the glove down the tools, indicating the NRL
material was getting trapped more in the grooves than the NBR material, as shown schematically in
Figure 7.20. The less stiff NRL glove will depress more into the grooves and get stuck as the finger
attempts to break the static friction and initiate sliding. This was demonstrated in Chapter 6 when
discussing the asperity contact and deformation with the steel strip. In this study however, the bulk
of the NRL material will be deforming on a macro level into the gaps of the tool treads, as well as at
an asperity level. The stiffer NBR however, will glide easier over the material due to less deformation
of the material into the gaps.
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NRL NBR
Figure 7.20. Deformation of gloves observed with tools. The lower stiffness of the NRL means the
material fills the gap, incurring more static friction. The NBR material is stiffer and sits atop the close-
gap tool pattern, incurring a lower static friction.
7.5.3 Contaminant interaction
Tools 1 and 5 have similar patterns with slightly differing depths and separation of
patterns/wavelengths. However, the friction coefficients between the glove materials are different.
This shows the effects the tread has on the presence of contaminants, as they will flow through the
tread pattern upon contact, either increasing friction or decreasing friction. Tool 4 has a close-knit
diamond pattern with a low tread depth, and little separation between the diamond tread. Overall,
this tool shows to have the lowest average friction amongst the contaminants. Contact area is the
likely reason for this decrease in friction. As the contaminants are introduced, the low depth tread
will be quickly filled by the fluids or the powder. This will cause the contaminant to ride above the
tread and ensure separation of the glove from the tool pattern, acting as an initial lubricant for the
system (106, 246). The thickness of the contaminant film/the amount deposited onto the glove, as
determined by the affinity and viscosity of the contaminant, will impact on how much separation
occurs once the glove is in contact with the surface (247). For example, in the NRL, the more viscous
oil tends to produce the lower friction but produces higher friction in many of the tools in the NBR.
This difference is noted with most contaminants between the gloves. In the NBR gloves, the
contaminants tend to show an increase in CoF with load, although in many cases, these are only
small changes, whereas NRL tends to show a decrease over the load. However, this is not true for all
contaminants. This is because of the way the contaminants are reacting on the surface. The
contaminants show affinity for the NBR gloves but are repelled by the NRL. High contact angles from
the contaminants with NRL indicate the contaminants are being pushed away as the force is
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increased, and friction decreases as the gaps are filled, as shown schematically in Figure 7.21.
However, alcohol was found to have a good surface wettability of the NRL and produces varied
results in friction across the tools.
Figure 7.21. NRL reaction with tools with low tread depth. Contaminants fill gaps easier as repelled
by the NRL material, this separates the glove from the surface, decreasing friction.
It is proposed that affinity and interaction with the gloves are the most important factors in whether
the contaminants will affect friction. These chemical interactions determine how the contaminants
behave on the gloves, as well as the prevalence of thicker films with different glove materials. In the
mixture solution, CoFs are notably higher in NBR than the NRL (except tools 5 and 6). In addition,
there are multiple differences in frictional behaviour between the materials. For example, in tool 4,
the CoF in both gloves is the same at the minimum normal force (~1 N), but an increase in load
causes an increase in CoF with the NBR material, but a decrease is observed with the NRL. During the
application of the contaminants, the fingers were held into the solutions and moved around to
encourage binding and interaction with the different components. Thus, differences in interaction
with the distinct components will encourage variances in surface wettability, film thickness, and
adherence of components to the gloves. This means, there was likely a difference in what
constituents were attracted to the different gloves when the finger was removed from the solution.
Electrostatic interaction
The gloves possess slight surface charges and contact with both the metal and the contaminants can
increase this charge potential. However, the influence of the charge increase is highly unpredictable
(248). NBR films encompass a positive surface charge, with more polar characteristics, whilst the NRL
film possess a negative surface charge with non-polar characteristics (14, 248, 249). Thus polymers
such as the oil, composed of triglyceride fats, protein (mucin), and the mixed solution will have greater
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differences in reactions over the loads between gloves (233). This would have either a lubricating effect
or increase adhesion properties of the contaminant, depending on the interaction with the glove
film.
Mucin film development
Of all the contaminants used, mucin appears to consistently give the highest CoFs between the
gloves with most of the tools. Previous studies have shown the development of mucoadhesive films
on surfaces. These mucoadhesive films form as a result of interaction with the environment, causing
proteins to fold in an loose water through self-assembly (250). This film development depends on
the environmental conditions, such as temperature and interaction, as well as the viscosity and
shear (233, 251, 252). Higher shear rates in a system have been shown to potentially elongate polymer
chains, making the system more ordered, affecting the lubrication and adhesion properties of mucin (233,
253). The groups surrounding the core peptide (central protein) of the mucin are dominated by
negatively charged carbohydrates. This gives an overall negative charge to the mucin structure at
physiological pH (234), and is also the contaminant which contains greater differences in positive
and negative domains (233), indicating the likelihood of differences in interaction with the two
oppositely charged materials. In addition, mucin has been shown to have good wettability with
different surface charges, such as the case with holding dentures (254). Together, the viscosity of the
mucin along with surface wettability and film development can increase adhesive properties when
handling equipment in a clinical setting (250). Great differences are observed with this protein
between the glove materials. Overall, the friction of the NRL gloves is higher with mucin applied in
tool 2, 3, and the smooth steel when compared to the mucin contaminated NBR. Furthermore, there
is a larger decrease in friction with the NRL in tool 1 and tool 7, whereas an increase is observed with
the NBR gloves with the mucin protein, indicating the nature of the protein behaviour is intrinsic to
the frictional properties.
The adhesive and lubricious properties of the mucin are dependent upon the interaction
with the gloves. Many oral tribology studies assessing mucin interactions study how the mucin
interaction is dependent upon the charge and the environment (255, 256). The protein will naturally
contort and respond to the environment it is put in. In this study, the interactions are based on the
electrostatic attraction and repulsion between both the gloves, and the protein itself (233). The
most dominant charge in mucin is the negatively charged carbohydrates, causing the negative
charge of mucin to interact more with positive charges. Thus, the protein will have a greater
interaction with the NBR gloves. Figure 7.22 indicates that the negatively charged mucin will be
attracted to both the positively charged NBR and the positively charged surfaces (248, 249, 257).
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This would bring the two surfaces together, increasing friction through both electrostatic interaction
and possible increased asperity contact. The NRL will, however, feel more charge repulsion from the
mucin, and the more positively charged regions of the core peptide will interact with the NRL,
leading to a weaker interaction than with the NBR.
Figure 7.22. Proposed representation of the attraction of charges between mucin-steel and mucin-
NBR and mucin-NRL.
In some cases the frictional properties of the NBR are decreased, such as the smoother tools (3, 4
and 7). This could be due to the interaction with the surfaces creating lubricating properties allowing
less time for film formation. Previous work with mucin has highlighted that the film formation is
more apparent on surfaces which have hydrophobic tendencies, such as the case in the NRL used in
this study (251). This is likely to be the reason for a higher friction than other contaminants. It is
proposed that the mucin has a higher affinity for the NBR, which causes a lubricating effect in some
tools, and in others, causes friction through film formation and the materials being pulled together.
On the other hand, the mucin is hydrophobically repelled from the NRL, causing surface separation
and decreased friction. As the CoF of the dry glove is generally greater than the NBR gloves, this
could be of a greater detriment to the glove user.
Film formation over time
Where these studies have been conducted, it must be kept in mind that the development of a
mucoadhesive tribofilm is not instantaneous. To assess the change in possible confirmation of the
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proteins, the dynamic friction was checked. Figure 7.23 shows that at 5.02 N, after around 7 seconds, the
friction of the NRL gloves steadily begins to increase on the smooth steel (tool 7). This is the likely to be the
development of a mucoadhesive film brought about by shear stress on the mucin, and the slight affinity of
the weakly positively charged metal surface (235, 252). This increase was apparent in both the NRL and NBR
gloves but was more prominent in the NRL. Further tests would need to be conducted by holding the
contaminated finger for longer on the surface before initiating the sliding. This would allow for a greater
insight into the development of the film formation.
Horizontal Force Normal Force

6
4
Force (N)
2 Steady increase in friction over time
0
0 2 4 6 8 10
Time (s)
Figure 7.23. Example of film development over time for a NRL glove with mucin applied, sliding on steel.
Alcohol
The alcohol solution shows similar contact angles with both gloves with similar estimated film
thicknesses. However, although a similar wettability was observed, the tribological properties of the
gloves were still affected in different ways. This is likely due to the way in which the gloves are
wetted, leading to different surface chemistry and interaction, as previously discussed with
protein/polymers. The alcohol is composed of two key components, ethanol (C2H5OH) and
chlorhexidine gluconate (C22H30Cl2N10). The hydroxyl group (OH) of the ethanol makes the compound
strongly polar, which will cause the OH group to attract to the NBR glove. On the other hand, the
ethyl group (C2H5) is non-polar, which will cause high wettability of the NRL surface (258). The
chlorhexidine gluconate is a strongly polar compound, which will be dissolved in the alcohol and
further add to the interaction with the polar NBR surface (259). As the gluconate is dissolved into
ethanol, there will be interaction, albeit weakly, with the non-polar NRL surface. A similar effect has
been noted with all contaminants. As different frictional properties, and behaviours are observed
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between the gloves, it is clear that knowledge of the affinity of the contaminants for the glove films
is vital for assessing frictional behaviour.
Evaporation and flow
Evaporation would cause more contact between the surface pattern and the glove than with other
contaminants. Although the gloves are of similar roughness, the NRL gloves are shown to have more
concave grooves, whereas the NBR looks to possess more convex grooves. This was also noticed in
the AFM images produced by Ho and Khew (56). The evaporation of the contaminant from the
surface is most likely to occur with the alcohol solvent, which was also included in the mixed
solution. This evaporation would be dependent on the airflow around the tool/glove and the time
between the solution being removed from the stock and placed onto the finger. Due to the concave
nature of the NRL pattern, as well as the deeper groves noted on the AFM, it is possible that when
the finger is placed on the tools, there would be less evaporation as more of the contaminant is
trapped in the deeper grooves. This would lead to a lower static friction, which is frequently
observed in the NRL glove, as the surfaces remain separated for longer. However, not considered in
this study, is that the fingers have some element of movement when gripping tools, the users may
pick up and put down the tool’s multiple times during use. This would, in effect, re-contaminate the
tool and the gloves, and the contamination already stuck to the surfaces may cause different
reactions on the surface.
Influence of powder on friction
When the gloves are contaminated with powder, rather than a fluid, the friction, is on average,
lower with the NBR gloves than the NRL. The lowest friction is observed when powder is present
with tool 6 when NBR gloves were worn, indicating that the powder could cause slipping when
holding disposable scalpels. For the frictional measurements with this tool, the finger was placed
onto the circle in the centre of the tool pattern, which does not have any groves, which would
maximise the contact area. The lower friction is due to the powder reducing contact area and
separating the surfaces sufficiently to reduce the friction of the glove-surface contact, similar to that
seen in Figure 7.21. This is also observed on the smooth steel (tool 7), which shows a greatly reduced
friction with both gloves when the powder is present. In some instances, such as tools 4 and 6 with
both gloves, there is an observed increase in CoF with increasing load. This could be due to the
differences in powder stuck to the gloves or small areas of inhomogeneity in the powder.
The powder used in this study consists of talc, also known as hydrated magnesium silicate.
As with the fluid contaminants discussed, the magnesium silicate contains domains that allow for
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both polar and non-polar interactions (260). Therefore, the powder will interact with both gloves.
However, more powder was found to be stuck to the NBR than the NRL. Although the amount on the
finger was small, and the difference between the two were found to be insignificant (t(2)=-1.538,
p=.541). Furthermore, the results of the AFM indicate the differences in behaviour, observed
primarily in tools 6 and 7, could be due to the variations in the way the gloves are being
contaminated. In the NRL, the large latex rubber clusters cause deeper gaps to form between
clusters, whereas the NBR is much smaller, and overall smoother. These smooth isolated regions
may have an effect on the interaction with the powder. As there are larger clusters of the NRL
material, there is surface interaction due to reduced isolated areas. However, more powder is likely
to be trapped in larger gaps between these clusters. It is possible that minute weights of this powder
fall out of these gaps upon contact/movement, which causes a reduction in friction by separation of
the surfaces.
Table 7.7 summarises the increase or decrease in friction at a 1 N force, to ease visualisation
of the effects the contaminants have on the gloves. In most cases, friction is reduced by the
contaminants. Those where friction is greater than the dry glove occurs with the NBR material,
primarily with alcohol and with tool 1, which has a low tread depth. Although similar in surface
texture, tools 3 and 7 were different materials, and different widths, and therefore contact area,
which gives rise to the differences in some of the frictional properties observed with the NBR.
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Table 7.7. Summary of frictional differences to the dry glove at 1 N load, where ‘L’ = lower than the
dry CoF, and ‘H’ = higher than the dry CoF.
Alcohol Mucin Oil Powder Water Mixture
Pattern NBR NRL NBR NRL NBR NRL NBR NRL NBR NRL NBR NRL
H L H L H L H L L L H L
H L H L H L L L L L L L
H L L L L L L L L L L L
L L L L L L L L L L L L
H L H L H L L L L L L L
7.6 Conclusions
The findings of this chapter are as follows:
• AFM of the glove films reveals the possibility of an adsorbed surface on the glove materials.
This is thought to arise as a function of the chlorination of the glove materials during the
manufacturing process and could impact the interaction of contaminants with the glove
materials.
• It has been shown that friction can be modified upon exposure to the contaminants used in
this study. NRL gloves were shown to be severely affected by contaminants, greatly reducing
friction. On the other hand, NBR gloves were shown to have both increases and decreases in
frictional properties, depending upon the tool pattern. The differences in the CoF of the
contaminated materials, in many cases, are not greatly affected by an increase in load.
• The change in frictional behaviour is dependent on the affinity of the contaminant for the
gloves, which modifies the ability to separate the surfaces and allows lubrication into the
system. The thicker the film, the greater the initial separation, which would induce lower
friction, which is observed in some cases in the NRL, which shows a poor surface wettability,
with hydrophobic tendencies. On the other hand, the NBR shows a good surface wettability,
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with hydrophilic characteristics. In addition to this initial film thickness, the chemical
interactions have changed the way the contaminants interact with the gloves, causing great
differences in the frictional properties between the two materials studied.
• The differences in frictional behaviour also depend on the tread pattern. Where the tools
were smoother, the friction was reduced greater when contaminants were present at the
maximum load.
• Differences in friction are likely to adversely affect grip in the NRL gloves, as decreases in
friction are more observable than in the NBR when contaminated, indicating equipment is
more likely to be near dropping/sipping from the user’s fingers. The tools which exhibit
higher friction coefficients will allow easier grip with less pinch force, which will in turn
reduce hand fatigue.
• As it is understood that the frictional properties of the gloves are easily modified by the
addition of contaminants, it needs to be identified as to how that impacts user performance.
It could be that the small friction modifications that are present have no effect on the user,
reducing the likelihood of problems occurring. However, the contaminants could change the
perception of the glove user, changing their sensitivity and affecting their dexterity.
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Chapter Eight: Effects of contamination on dexterity and
sensitivity
At the forefront of the literature assessing medical gloves is dexterity and sensitivity. However, the
inclusion of contaminants, making the assessments more relevant to realistic situations, have been
neglected in the literature (6). Highlighted in Chapter 7 was the requirement for more performance
assessments to be conducted in-situ. It was shown that the frictional properties of both NRL and
NBR materials were affected by contamination from a variety of substances. In many cases, this
lowered the frictional properties of the gloves, especially with the NRL gloves. This chapter explores
this contamination further, assessing if, and how, contaminants affect the performance capabilities
(dexterity and sensitivity) of the user (232).
8.1 Introduction
Understanding if the differences in frictional properties, observed in Chapter 7, influence the
performance measures, such as dexterity and sensitivity, is vital to understanding the effects gloves
have on the user. Stimuli changes on the fingers are a result of friction created by the deformation of
skin. This deformation and friction create surface strains that propagate to mechanoreceptors,
which are vital for sensory perception, allowing for physical feeling (63, 189). They also play a vital
role in providing feedback regarding grasp. Therefore, the tactile sensation is also pivotal in
preventing slipping and manipulation of objects (261). The presence of a contaminant on the gloves
could affect tactile sensation by way of dampening the stimulus, which could lead to incorrect
patient care through missed information or dropped equipment. Furthermore, external substances
on the gloves could change the perception of the glove user, especially in cases where the
contaminants are of a different temperature. This has been shown to affect the dexterity of
participants when completing pegboard dexterity tasks (262).
8.2 Aim and objectives

The aim of this study is to assess to what extent glove user dexterity and sensitivity is affected by the
contamination assessed in Chapter 7. Mucin has been chosen from the contaminants used in the
previous chapter to contaminate the gloves. Due to the differences in frictional behaviour observed,
mucin was perhaps the most intriguing due to the intrinsic nature of the protein. Specifically,
porcine gastric mucin has been observed to display similar behaviour and viscosity to human mucin
found in saliva (233, 254). This allows for conclusions to be drawn on how saliva/mucus in the body
may influence the dexterity and sensitivity performance of the glove users. In Chapter 7, the mucin
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was shown to give different frictional properties for both of the gloves. This was due to the
differences in behaviour of the polymer chains, the interactions with the tools, and ultimately the
reactions with the glove films (233, 234, 250). Mucin is a long chain protein, surrounding by
carbohydrate chains, which aid interaction through the contortion of proteins (233). This contortion
happens due to the interaction with the glove material surfaces. The negatively charged NRL repels
the mucin, which aids mucoadhesive film formation over time. The positively charged NBR draws
more mucin to the surface and causes differences in frictional properties when compared to the NRL
(248, 249). Therefore, it is expected that there will be differences in dexterity and sensitivity
performance due to the different way in which the gloves and mucin are interacting with the
environment. In addition, out of the contaminants selected in Chapter 7, mucin is most likely to be
contacted in a medical setting, given the contaminants discussed in Chapter 3 (233). Understanding
the effects of contaminants on examination glove users is salient to comprehending whether
contamination is detrimental to the tasks being carried out.
8.3 Materials and methods

8.3.1 Participants
A total of 15 participants (13 male and 2 female) took part in the dexterity tests, and 12 (10 male
and 2 female) took part in the sensitivity tests. All participants were asked if they had any
sensorimotor deficiencies, any allergies to latex, or any conditions that could affect their sensitivity
or dexterity. All participants were recruited from The University of Sheffield and were aged between
22 and 34 years (for both tests). Ethical approval was received by the Research Ethics Committee of
the Department of Mechanical Engineering, University of Sheffield (No: 016619).
8.3.2 Glove selection and analysis

Participants donned the same glove make and model used in Chapter 7, for consistency. These were
powder free, chlorinated NBR and NRL gloves, which were found to have similar thicknesses NBR=
0.106 (±0.006) mm; NRL= 0.114 (±0.007) mm). Participants were selected gloves based on their
perceived “best-fit” (the glove size they would ordinarily use), however no measurements were
taken of the hands for this section of work. Visual inspections were carried out to ensure gloves fit as
expected. Gloves were expected to conform to the fingers and the hands with little to no areas of
loose material, as described in Chapters 4, 5 and 6. The medium glove size was the “best-fit” choice
for all participants with both glove materials, except for two who requested large NBR gloves but
were comfortable with the medium NRL gloves.
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FTIR
In Chapter 7, it was shown through contact angles, estimated film thickness, and the amount of
mucin deposited onto the gloves, that the mucin has a stronger affinity for the NBR than the NRL,
Therefore, to further assess if any surface binding takes place, FTIR was conducted. Samples were
prepared by cutting off the fingertip of the glove (around 3 cm). Two samples were produced for
each glove type: washed and unwashed. This allowed the determination of whether the surface has
been cleaned by the water, or if the mucin has bonded/changed the surface chemistry. FTIR analysis
was conducted using a Brucker ATR-FTIR instrument. Each sample was scanned 26 times in the 550-
4000 cm-1 region with a resolution of 4 cm-1. Two areas of each glove were analysed and averaged by
OMNIC software. Using a Pasteur pipette, 1 ml of the mucin solution was placed onto the outer
surface of each glove left for 10 minutes. The ‘washed’ sample was then held in a beaker of water (at
20-22oC) and stirred for 10 seconds. The sample was then removed and left to out dry. The
‘unwashed’ sample was patted with a clean, dry tissue to remove any visible residue on the surface
of the glove. Both washed and unwashed samples were left to dry for a minimum of 24 hours before
analysis (16-24oC). Each test was repeated three times for the NBR and NRL gloves (three washed
samples and three unwashed samples). Three samples of each glove material were also analysed in
an uncontaminated condition.
8.3.3 Dexterity measurements

Gross dexterity
Gross dexterity was measured using the Purdue pegboard, as discussed, and used in Chapter 6 (see
Section 6.3.3). This was chosen in line with the previous reasons, the ease of implementation of the
test to be used in industry, the ease of results comparison, and the ease of the test to be conducted
by participants. As in the previous pegboard test, the participants completed all four tasks, which
was split into two scores (combined and assembly test). The combined test consists of the number
of pins placed in thirty seconds using the left hand, right hand and both hands (1.5 minutes in total).
The assembly test consisted of the number of parts assembled in the pin-washer-collar-washer
structure within the 1 minute allocated time. Participants who dropped pins, or assembly parts,
were instructed to leave them and then pick up another for their allocated dish, so as not to waste
time.
208
Fine dexterity
The Crawford Small Parts Dexterity Test (CSPDT) was chosen as an extra measurement of dexterity in
this test. In medical tasks, fine dexterity using tweezers (and other tools) is salient to performance,
thus assessing the effects of contaminants on the gloves with finer measurements would be
insightful (114). As with the Purdue pegboard test, the board is small, and easy to use as well as
implement into industry. The CSPDT, designed by Crawford and Crawford (263), has been discussed
in Chapter 2 as a common test used for glove performance assessments (see Section 2.6.2). This test
consists of two parts: pin and collar placement and screws placement. For this study, only the pin
and collar test were chosen to be conducted, for both the constriction of time and the relevance to
medical glove users in clinical practice.
The pin and collar test consists of a board filled with 36 holes. Next to the board there are
three dishes, one contains screws (not used for this test), one contains cylindrical metal pins, and
one contained small metal collars. The aim of the test is to use tweezers to place the pins into the
board and place a collar on top, as shown in Figure 8.1. Each pin must contain a collar before moving
onto the next pin placement. The score is the time taken to complete the task. Due to the number of
conditions and tests in this study leading to time restraints, only half the board was filled (n=18). As
with the Purdue pegboard test, the participants were told if they dropped any part, to not attempt
to pick up the parts and obtain a new respective part from the dishes.
Figure 8.1. CSPDT pins and collar test.
Test familiarisation and learning behaviour

As in Chapter 6, the participants were made to practice the tests prior to the experiment being
conducted. This was to circumvent any learning behaviour as the tests were conducted. These tests
were carried out in the bare hand condition and were scored to establish a plateau in the results. A
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plateau was defined as three results in a row being similar (±2 pin/assembled parts for the Purdue
test and ±3.0 seconds for the CSPDT), after a minimum number of 5 trials in each of the tests. In
addition to this, to assess the possible effects of further learning behaviour throughout the dexterity
tests, participants were asked to repeat one random condition to check for differences with their
previous result. For example, once a participant had completed a test, they were then instructed to
repeat the test in the same condition. The choice of which condition was re-tested was
predetermined for each participant before the tests were conducted, and always fell near the end of
the study (3rd or 4th test) as this is where learning behaviour is more likely to take effect. With the
repeated test results, the first score was used in the data analysis if the results were different upon
repetition.
8.3.4 Sensitivity measurement

The sensitivity test was chosen based on previous work conducted by Mylon et al. (88) who
developed two simulated medical tactile tests (SMETT) to measure cutaneous sensibility. These tests
have been discussed in Chapter 2 (see Section 2.6.1). Only the ‘Bumps’ SMETT test was selected for
this study, as differences between gloves were more apparent in the study by Mylon et al. (88) with
this test.
The bumps sensitivity test is composed of a flat elastomeric sheet with an attached guide,
allowing for the finger to move down the columns, as shown in Figure 8.2a (14.0 × 14.0 × 0.8 cm). At
random location across the sheet, 26 bumps have been manufactured onto the surface. The
hemispherical bumps start at a height of 100 µm in size and increase by 20 µm up to 600 µm (Figure
8.2b). The participants were instructed to place their finger pads flat onto the surface, keeping the
finger at around a 40° angle to the test bed, similar to the friction tests conducted previously in this
thesis. This was to standardize the test and make the results more comparable between
participants. If participants had applied their fingers so as to be aligned perpendicularly to the
elastomeric sheet, the dispersion of mechanoreceptors activated is fewer than when the finger pad
is horizontal to the board (264). In the previous study by Mylon et al. (88), the finger position varied
between participants, making the results incomparable.
210
a) b)
600 100 320

540 260 360 280 400 220
580 500 160 560 120

200 340 140
520 440 480 380
180 240 460 300
420
Figure 8.2. a) Bumps test bed developed by Mylon et al. (88) b) location and size of bumps (µm).
A light dusting of talcum powder was used, as in the original study (88). Efforts were made to avoid
using this, to better understand the effect of gloves on tactile ability without a contaminant present.
However, the contact induced too much friction and the fingers were found to slip in the gloves, and
the polymer-polymer contact induced stick-slip friction. The talcum powder was spread as lightly as
possible on the surface and practices were conducted to assess how light the dusting could be to
reduce the friction. It was found that that a light dusting was sufficient. As this made some of the
bumps visible on the surface, the participants were asked to close their eyes and their finger was
guided by the researcher to the top of the plastic guide. Thus, the participants did not see the test
bed in detail until after all tests were completed, to eliminate bias. Participants could explore each
column at their own speed and were allowed run their finger up and down at their own leisure. All
columns were used in each test and the columns were chosen in a forced randomized fashion before
the study to further eliminate bias. In addition to this, the test bed was rotated 180° to increase the
randomized possible orientations and prevent learning behavior for each test.
8.3.5 Mucin and application

Porcine gastric mucin (Type II, un-purified) was heated to physiological body temperature (37oC) via
a water bath whilst in use. The mucin solution was the same as used in the previously in Chapter 7.
To apply mucin to the gloves, participants dipped their gloved fingers into the solution (Figure 8.3).
Unlike the application in Chapter 7, there the finger was dipped to the interphalangeal joint, in this
study the fingers were dipped up to the knuckles to cover all the fingers. The fingers were held into
the solution for 10 seconds. When removed, the mucin was rubbed over the palm and between the
fingers using the dipped fingers of the same hand. This was to assess if the drying, crystallisation, or
211
presence of mucin around the hand had an effect on performance. Excess mucin was shaken off
until no drops fell from the glove, and then the test was conducted.
Figure 8.3. Application of mucin to the glove.
Mass transfer
As with the contaminants in Chapter 7, preliminary experiments were carried out to measure the
weight of mucin transferred to the gloves by following the mucin application procedure. Participants
were found to wear only medium and large gloves, thus only these sizes were measured. Two
participants (both best-fit medium sized hands) donned five of each glove type and size (20 gloves in
total). Mucin was applied using the procedure described. Gloves were then removed and weighed
using a 5-point analytical balance (Analytical Sartorius, ±0.0001 g) to determine the amount of mucin
transferred to the gloves.
8.3.6 Experimental procedure

All of the tests (Purdue pegboard, CSPDT and Bumps sensitivity) were performed in one 2 – 2.5-hour
session with time for resting in between to avoid fatigue. Each of the dexterity tests were carried out
in were carried out in 4 hand conditions: NRL, NRL + mucin, NBR and NBR + mucin. The sensitivity
test encompassed the same conditions and a no-gloves condition. The order of tests conducted, and
hand test conditions were conducted in a forced randomised fashion. This is a way of randomising
test conditions, whereby permutations were checked and altered where applicable, to prevent
certain conditions always being in a certain position. Participants were also not informed of the
gloves being used, and packaging was removed prior to glove selection. However, due to the
common colour variation between gloves, some participants were aware of which glove materials
they were using. Tests were carried out at The University of Sheffield with a room temperature
between 21.0-24.3oC. To eliminate the possibility of contamination, all of the equipment, with the
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exception of the gloves which were changed between tests, was cleaned with acetone and water
between all tests.
8.3.7 Statistical analysis

Gloving conditions were compared to check for statistically significant differences within the raw
data. Each set of data was checked for normal distribution using the Shapiro-Wilk Test for normality
(192). The null hypothesis is that the mean result of each condition showed no difference between
the two compared tests. Statistically significant differences are shown at p<.05. Where the null
hypothesis of normality was not rejected within the data, statistical analysis was carried out using
one-way analysis of variance (ANOVA) followed by a post-hoc Tukey’s Honestly Significant Difference
(HSD) where applicable (194). Where the dataset was rejected for normal distribution, the non-
parametric Kruskal-Wallis test was conducted followed by a Dunn’s Multiple Comparison test to
assess where any significant difference occurs, if applicable (195).
8.4 Results
8.4.1 Mucin transfer
The weight of mucin determined to be on the gloves is shown in Figure 8.4. The medium sized NRL
gloves averaged a deposit of 0.49 g (±0.026 g) of mucin, whereas larger gloves averaged 0.52 g
(±0.056 g). Mucin on the medium NBR weighed, on average, 0.60 g (±0.067 g) whereas on the large,
mucin weighed 0.62 g (±0.025 g).
0.8
0.7
0.6
Mucin Weight (g)
0.5
0.4
0.3
0.2
0.1
0
NBR Medium NBR Large NRL Medium NRL Large
Glove Material/Size
Figure 8.4. Mucin adherence to medium and large sized NRL and NBR glove. Error bars denote
standard deviation.
213
8.4.2 FTIR
NBR
After the mucin application, there are slight changes in the NBR spectra compared to the washed
glove, which are shown in Figure 8.5. The unwashed mucin sample has the absence of the C-O ester
peaks at the 1050-1000cm-1 wavelength. The washed sample does have these peaks, but they are
severely decreased in absorbance compared to the uncontaminated NBR gloves. This could be due
to mucin being present on the surface. The increase in broadness and intensity of the peak from
3500-3100cm-1 indicates the presence of more hydroxyl groups (OH) on the NBR gloves. The overall
absorbance of the uncontaminated NBR is dominant in the spectra, indicating that some of the
mucin could still be present on the surface in the washed sample, reducing peak intensities. A higher
intensity of peaks in the region from 900-400cm-1 is shown for the unwashed sample. This could be
due to the mucin carbohydrates increasing the C-H intensities and the presence of disulphide
bridges from the existing cystine links within the mucin (265). However, this is decreased after
washing, indicating that washing has decreased some of the presence of the mucin (210). The peak
shown at 2356-2332cm-1 shows the C-O bond of carbon dioxide, which has arisen because of an
increase of CO2 in the atmosphere around the sample, rather than the sample itself. These results
show there are some changes to the surface of the NBR gloves when exposed to the mucin, which
cannot be reversed with washing.
Figure 8.5. Spectra of NBR and mucin contamination.
214
NRL
The spectra for NRL when mucin is applied is shown in Figure 8.6. The unwashed sample has a peak
at 1256 cm-1 which is absent from the washed sample. This is indicative of the carboxylic acid
(COOH), which could arise from the terminus of the mucin proteins (265). Confirming mucin is likely
to be on the gloves surface, as expected. There is also less absorbance of the main peaks in the
unwashed samples, which indicates a reduction in the C-O/amine region between 1500-1300 cm-1
(210). There is very little difference between the clean sample and the washed sample. The slight
reduction in absorbance could be due to the washing procedure or variation in the structure, as
discussed regarding the AFM in Chapter 7. These absorbance shifts are minimal and are enough to
indicate that the mucin has been removed from the surface of the NRL, showing very little and weak
affinity of the mucin for the NRL material.
Figure 8.6. Spectra of NRL and mucin contamination.
8.4.3. Gross dexterity (Purdue pegboard test)

Left, Right and Both Hands (Combined Test)
The results of the combined Purdue pegboard test are shown in Figure 8.7. Data have been
normalised against the dry glove condition (mucin contaminated time - dry glove time) to highlight
the differences between gloving conditions and compare the impact of the mucin on the score.
ANOVA tests were conducted, after the data were found to be normally distributed throughout the
215
four conditions. The ANOVA shows statistically significant differences within the data (F(3,66)=3.042,
p=.009). Tukey’s HSD test results are shown in Table 8.1. NRL was shown to perform better, on
average, than NBR with a score of 43 (±8) pins being placed, which is 1 greater than the NBR gloves
(42 pins placed ±6). However, this was not significantly different (H=1.400, p=.786). When mucin was
applied to the gloves, NBR was shown to have significant increase in dexterity, with the number of
pins being placed averaging 46 (±6) (H=4.209, p=.012). This increase in performance was observed
throughout all participants. On the other hand, with the NRL gloves, scores were lower than the dry
condition with 43 pins being placed (±6). However, this was not significantly different from the dry
performance (H=1.400, p=.786). The score was found to be 4 pins greater, than dry condition, with
mucin contaminated NRL gloves in 2 participants. The remaining 13 participants were found to have
lower performance scores with the contaminated NRL. Significant differences were found between
the NBR and NRL when mucin is applied to both sets of gloves (H=4.209, p=.013).
NRL
Glove
NBR
-2 -1 0 1 2 3 4 5
No of pins placed
Figure 8.7. Normalised (mucin contaminated time - dry glove time) scores of combined Purdue
Table 8.1. Tukey’s (HSD) test results for the different gloving conditions in the Purdue pegboard
combined hands result (ANOVA F(3,66)=3.042, p=.009).
NBR + NRL +
Condition NRL
Mucin Mucin
H=4.209 H=1.400 H=0.002
NBR
p=.012* p=.786 p=.900
NBR + H=2.829 H=4.209
Mucin p=.179 p=.013*
H=1.400
NRL
p=.786
*Indicates statistical significance (p<.05)
216
The number of dropped pins are displayed in Figure 8.8. The results show that the number of pins
dropped when the NBR is contaminated, is no different from the uncontaminated (NBR= 0.60, NBR +
mucin= 0.60). The same is observed in the NRL, however, more pins were dropped on average (NRL=
0.67; NRL + mucin= 0.67). Although the average number of pins dropped is higher in the NRL, only 9
pins were dropped in both sets of NBR gloves, and 10 were dropped in the NRL condition.
0.68
Average No of pins dropped
0.66
0.64
0.62
0.60
0.58
0.56
NBR NBR+mucin NRL NRL+mucin
Glove
Figure 8.8. Average number of pins dropped across the gloving conditions in the combined test.
Assembly Test
The normalised (mucin contaminated time - dry glove time) results of the assembly segment of the
Purdue pegboard test are displayed in Figure 8.9. The average number of parts assembled for the
NBR (32.53 ±4.70) was found to be lower than the NRL (33.80 ±7.42). When contaminated with
mucin, the gloves do exhibit differences in results. A decrease of 4.27 parts assembled is observed
with the NRL gloves (average= 29.53 ±4.55). A decrease in the parts assembled were noted in all but
one of the participants wearing contaminated NRL gloves. However, the number of parts assembled
when the NBR glove was donned, increased by 1.60 (average= 34.13 ±3.85). This increase in score
was observed in all participants. ANOVA tests show there is no statistically significant differences
present between any of the data sets (F(3,66)=1.838, p=.084).
217
Latex
Glove
Nitrile
-6.00 -4.00 -2.00 0.00 2.00 4.00

Number of parts assembled (normalised)
Figure 8.9. Normalised (mucin contaminated time - dry glove time) scores of assembly Purdue
The number of parts dropped between the two conditions with each gloves also shows a difference,
which is shown in Figure 8.10. When gloves are contaminated, both materials led to the dropping of
5 more parts than in the dry condition. In addition, more parts were dropped in this section of the
test than previously (NBR=0.53; NRL; 0.67). More parts were dropped with the NRL gloves (10 pins,
0.87 average) than the NBR (8 pins, 0.67 average).
1.0
0.9
Average No of parts dropped
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Glove
Figure 8.10. Average number of parts dropped across the gloving conditions in the assembly test.
8.4.4 Fine dexterity (CSPDT)

The results of the fine dexterity test (with pins and collar placement being completed with tweezers)
show that when the NRL gloves were donned, the user performance was slightly quicker (1.83 ± 0.36
min) than the NBR (1.88 ± 0.34 min). However, the slight increase in speed is not significantly
218
different (Z=0.874, p=.382). The normalised (mucin contaminated time - dry glove time) results for
the CSPDT are shown in Figure 8.11. The results show that the performance with both gloves
increased upon addition of mucin. When mucin was exposed to the NRL, the test was completed 3.6
(±16.8) s quicker than the dry condition. The increase in speed was noted in 12 of the participants,
where three were found to take longer in the contaminated condition. When the NBR was
contaminated, the test was performed 15 (±21.0) s quicker than the dry condition. All participants
were shown to perform quicker when the mucin contaminated gloves were worn. All datasets were
found to be non-normally distributed. Therefore, statistical analysis was carried out using the
Kruskal-Wallis test. Statistically significant differences were found amongst the different conditions
(H(3)=9.754, p=.045). Table 8.2 shows the results of the Dunn’s post-hoc tests, which reveals
significant differences to be between NBR conditions (dry and with mucin) (Z=-2.652, p=.008).
NRL
Glove
NBR
-0.35 -0.30 -0.25 -0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10
Time taken (s)
Figure 8.11. Normalised (mucin contaminated time - dry glove time) time from CSPDT test. Error bars
denote standard error.
Table 8.2. Dunn’s post-hoc test results for the different gloving conditions in the CSPDT results.
NBR + NRL +
Condition NRL
Mucin Mucin
NBR Z=-2.652 Z=0.874 Z=-1.405

P=.008* p=.382 P=.160
NBR + Mucin Z=-1.787 Z=-1.256
p=.074 p=.209
NRL Z=0.532
p=.595
*Indicates statistical significance (p<.05)
219
Figure 8.12 shows the average number of pins dropped per test. On average, the participants
dropped fewer pins in this test than the gross dexterity tests, with 4 pins being dropped in the NRL
condition (average= 0.27), and 5 pins dropped in the NBR (average= 0.33). When mucin is added,
there is a slight decrease with the NBR, with 4 pins being dropped in total (average 0.27). The NRL
however, remains the same, with 4 pins being dropped across all participants (average= 0.27).
0.40
0.35
Average No of pins dropped
0.30
0.25
0.20
0.15
0.10
0.05
0.00
Glove
Figure 8.12. Average number of pins dropped across the gloving conditions in the CSPDT.
8.4.5 Sensitivity
One participant was only able to identify grooves running parallel between B and C as well as F (highlighted
in Figure 8.13). These are not part of the test and presumed to be a fault in the manufacturing process.
However, they were not mentioned in the previous experimentation by Mylon et al. (88). These grooves
were noted by some of the other participants; however, they were also able to identify the bumps
intended to be sensed. Another participant did not identify any bumps in any of the conditions, or without
any gloves donned. Therefore, data for these two participants has been eliminated from the analysis (n=10).
220
Figure 8.13 a-c. Grooves horizontal to the board. a) bumps test bed. b) groove running across
between rows B and C, and c) groove running across row F.
Figure 8.14 shows the percentage of bumps detected in each gloving condition plotted for each
bump size. All participants detected all of the bumps between 600 m and 300 m in the bare hand
condition. When gloves were donned, this was shown to increase to 380 m for the dry gloves. With
the bare hand, participants felt bumps down to 180 m, giving an average detection of all bumps at
75.2%. However, when gloves were donned, the LOD was shown to decrease. In the NBR gloves, the
LOD 280 m, when contaminated with mucin the LOD did not decrease, however 30% more
participants were able to detect down to the 280 m, rather than 10% in the dry condition. NRL had
a greater rate of detection, with a LOD down to 220 m. However, when mucin was applied, the
detection rate decreased to 260 m. Although the detection rate of the bumps is still better in the
NRL, the mucin has been shown to increase detection of the bumps in the NBR.
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No Gloves NBR NBR + Mucin NRL NRL + Mucin
100
90
80
70
Bumps detected (%)
60
50
40
30
20
10
0
100 150 200 250 300 350 400 450 500 550 600
Bump size (µm)
Figure 8.14. Results of bumps sensitivity test showing the percentage (%) detection rates at each
bump size.
8.5 Discussion
8.5.1 Binding of mucin
The spectra of the FTIR confirms the previous tests regarding the binding and affinity of the mucin
for the NBR glove, and less attraction to the NRL. The mucin was easily washed off of the NRL, but
changes remained on the surface of the NBR after washing. That is not to say that mucin is still
present on the surface of the NBR after washing, as the changes in the spectra could be down to
other factors, one of which could be due to the leaching of phthalates out of the gloves. It is
documented that the microstructures of polymers change with exposure to water due to phthalate
leaching (207, 266). However, this process tends to occur over a longer period than used in this
study. There are several other additives that contribute to the observed spectra, such as the
stabilisers, dyes, antioxidants, and treatment methods. It is possible that some of these additives
could have reacted with the mucin in this study, resulting in the observed spectral changes. NBR and
NRL both degrade by oxidative chain scission, a process whereby oxygen will break the C=C bonds to
become C=O, breaking the polymer chain (267, 268). Occurrence of a C=O band does occur at
stronger absorbances with NRL and mucin, but not in the NBR and mucin, leading to the inference
that there may be differences in the changes with the microstructure of the mucin itself when on the
gloves. Differences could arise due to changes in orientation of polymer chains, degree of
222
crosslinking and degree of crystallisation of the mucin, as discussed in Chapter 6 (269). In order to
understand the changes on the surface, confirmatory chemical analyses could be used to explore
that. However that was considered to be beyond the scope of this work. It is clear that the mucin has
a stronger attraction to the NBR material, as it causes changes in the surface chemistry of the glove,
has a larger estimated film thickness and greater contact angles than the NRL material.
8.5.2 Effects of mucin on dexterity

In Chapter 6, it was shown that the stiffer gloves had a greater detriment to dexterity. Therefore, it
was thought that, as the mucin dried, the gloves may feel stiffer due to the evaporation, and the
differences in this perception may affect performance. As no other studies have been found
assessing how contamination affects the dexterity performance of gloves, is it not clear what is
occurring to improve dexterity with NBR, but not with NRL in the pegboard test. The assembly test
proved to be more difficult when the mucin was present on both gloves, and participants noted
more difficulty in their ability to carry out the task when using NRL. Where lubricated, a greater level
of fatigue can be induced through increased, and prolonged, gripping. The drying and stiffening of
the mucin protein may occur over a prolonged period, especially with more tasks and a variety of
movements seen in the medical profession. However, it does not appear to be the case in this study,
or with this particular contaminant. It is most likely the increase in dexterity is a result of a more
‘optimum’ friction, and ability to feel. If pins and parts are easier to grab and place, as is the case
with NBR and mucin, performance will be quicker.
External stimuli and temperature
When gloves are contaminated with proteins, such as mucus, there is a greater risk of dexterity
changes due to changes in feel and possible micro changes in the surface structure, as shown in the
FTIR results. Perception of performance is also known to have an effect on dexterity (270). It has
been shown in previous studies that performances are affected by an environmental stimulus. A
review by Heus, Daanen, and Havenith (271) showed that both gross and fine finger dexterity is
significantly reduced when the psychological effects of the cold are exerted onto the human body.
More specifically when assessing effects of external stimuli on or around the hands, Maley, Minett,
Bach, et al. (272) found that performance with the Purdue pegboard was significantly decreased
when the arms of the participants were cooled to 10°C. However, Ray, Sanli, Brown, et al. (273)
found little difference between dry hands and hands when wet or cold after completing the
pegboard test. However, the study does show a decrease in performance when the hands are both
wet and cold. It is possible these studies are measuring the effects of muscles constricting to
preserve warmth. In this study, warming of the hands (through the heated mucin) may have
223
improved gross dexterity with the NBR but decreased gross dexterity with the NRL gloves. An
increase in dexterity as a function of increase in temperature has been shown previously by Chen,
shih, and Chi (262), who showed a strong correlation between warm hands and an improved
performance with the Purdue pegboard. As the gloves move, the protein will cool down over time,
which will induce evaporation and different sensations on the hands. The cooling effect could be
perceived differently through the materials, brought about by distinct interactions of the mucin with
the glove, specific hand movements, film thicknesses, and heat transfer. It is possible the dexterity of
the NRL was affected by the cooling action as the mucin was repelled, however the temperature was
not checked over the course of the study. Much of the work conducted looking at the effects of
external stimuli are centred around lighting and temperature, rather than something pressing
against the hand or the sensations as something being exposed to the hands/evaporated.
Protein conformational changes
The mucin would have changed in viscosity due to the movement and differences in pressure being
applied (235, 274), which would affect how the mucin feels when pins are being grabbed (i.e. a
thicker formed mucoadhesive gel will change instinctive applied force, than a watery solution).
Furthermore, the movements and airflow around the protein can cause differences in mucin interaction as
well as the physical properties of the gloves. As the gloves move, the already decreasing temperature will
be rapidly decreased further. Ligtenberg, Meuffels, and Veerman (275) shows that at a lower temperature
the flow rate of saliva decreases, due to mucin aggregation and changes in protein conformation. Again, this
would have an effect on the perception when participants grab the pins in the Pegboard test, and when
holding the tweezers in the CSPDT. The results of dexterity tests, where changes are occurring over the
course of the test, need to incorporate the psychological aspects of the perception of the task. It is
proposed that as the NRL is generally tighter fitting to the hand, as observed in previous chapters (Chapters
4, 6 and 7), the cooling effects as well as the changes in protein viscosity and conformation have a greater
effect on the participants. This could be the reason for the increase in dexterity with the CSPDT, because of
the more static position, the participants may not be feeling and responding to the changes over time.
The changes in conformation of the protein may also be a reason for performance decrease in both
gloves with the assembly tests. Excess mucin dropping off of the gloves into the washers appeared to be the
greatest hurdle, as the washers stuck together and required separation. The mucin in this position would
also pull the positively charged metal to the mucin, making separation of these washers slightly more
difficult. This was more frequent in the NRL gloves, over the NBR, as more mucin ran off of the NRL gloves
due to less mucin-glove interaction.
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8.5.3 Friction and film formation
Purdue Pegboard
Where mucin was present, it was noticed when participants had NBR gloves donned, users had
difficulty trying to grab washers from the concave dishes. However, the difficulty was apparent when
trying to grab all components when NRL was donned. The frictional properties of both the NRL and
NBR gloves are shown in Figures 8.15 (a-b). These are taken from the friction obtained in Chapter 7
(see Section 7.4.3), assessing friction with tool 7 (smooth steel), which is replicable of the surface of
the pegboard pins, as discussed in Chapter 6. The CoFs decrease on average by around 0.19-0.28, across
all loads, when mucin is applied to the NBR glove. When mucin is applied to NRL gloves, the friction
decrease is greater. At the 1 N target load, the CoF decreased by 1.18, which then reduces to between 0.84
and 0.89 across the loads. However, it does not appear that the mucin affected the frictional properties
to the extent that many more pins were being dropped. Further work could be conducted to
measure the loads used to grab the pins, in addition to further assessments of the dropping
frequencies, in order to evaluate how the mucin may affect grip. It may be that the participants were
likely experiencing difficulties in adjusting the grip to accommodate the changes in frictional properties.
Thus, participants could have been taking longer to pick up the pins when the gloves are
contaminated with the mucin. The higher affinity of mucin for the NBR gloves is aiding optimal
friction and adhesion, allowing pins to be picked up more easily in the Purdue pegboard test. The
protein conforming under a higher load over time as the water is pushed aside appears to decrease the
friction in the NRL.
a) NBR Dry NBR + Mucin NRL Dry NRL + Mucin

b)
2.4 2.4
2.0 2.0
1.6 1.6
CoF
CoF
1.2 1.2
0.8 0.8
0.4 0.4
0.0 0.0
0 2 4 6 0 2 4 6
Normal Force (N) Normal Force (N)
Figure 8.15 (a-b). CoF of a) NBR and NBR with mucin; b) NRL and NRL with mucin on smooth steel
across a 1-5 N target load range (as tested in Chapter 7). Error bars show standard deviation.
225
CSPDT
When assessing fine dexterity in the CSPDT, it is shown that when mucin is present, there is an
increase in dexterity with both glove materials. The NBR is shown to allow a much greater dexterity
than the NRL when contaminated with mucin. It would appear in the fine dexterity, addition of the
mucin causes an ‘optimum’ friction, due to the formation of a mucoadhesive film. This is aided by
the static positioning of the thumb and proximal index finger skin/index finger pad, which would
contain some mucin between the metal and the gloves. Under shear stress, this film formation
prevents microslips through an increased adhesion (233, 250). However, the friction coefficient of
the gloves when mucin is applied, is shown to be lower in Figure 8.16(a-b), which is reproduced from
the results in Chapter 7 (see Section 7.3). It must be considered that the friction test was unlike the
conditions used in the CSPDT, where the average elapsed time was around 3.5 minutes and there
was some movement of the hand. In the friction tests the finger pad was placed onto tweezers and
moved down after holding for a few seconds. Thus, it is unlikely a tribofilm had developed during the
friction tests.
a) NBR Dry NBR + Mucin NRL Dry NRL + Mucin

b)
1.4 1.4
1.2 1.2
1.0 1.0
0.8 0.8
CoF
CoF
0.6 0.6
0.4 0.4
0.2 0.2
0.0 0.0
0 2 4 6 0 2 4 6
Figure 8.16 (a-b). CoF of a) NBR and NBR with mucin; b) NRL and NRL with mucin on tweezers (tool
5) across a 1-5 N target load range. Error bars show standard deviation.
Thus, it is hypothesised that there is more affinity of mucin for both the NBR gloves and the metal,
which is aiding friction by bringing the surfaces closer together, allowing pins to be picked up more
easily in the Purdue Pegboard test. This allows for greater precision when completing the tasks.
When applied to NRL, the mucin has less affinity for the surface and may be acting as a lubricant in
the first instance, making the surfaces more slippery and harder to grip. However, over time, the
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movement and change in force when grabbing pins/tweezers aided the thinning of the mucin
viscosity, which would have contributed to changes in the mucin. The muco-adhesive film takes time
to form and is not instantly apparent, as these tests were 30 seconds/1 minute, there may have not
been enough time to allow development of this film. This hypothesis is also supported by the results
of the CSPDT which shows that mucin improved dexterity to participants when wearing both glove
materials. The static positioning of the finger and thumb used to hold the tweezers has allowed the
formation of a thin muco-adhesive film, negating any microslips between the gloves and the metal.
In conjunction with this, the tweezers had textured grooves on the surface to enhance grip. The
mucin could have flowed into these and increased the contact area with the gloves, further
increasing friction.
8.5.4 Effects of mucin on sensitivity

Mylon et al. (88) observed that NBR had a higher detection rate than NRL when compared to the
bare hand, whereas this study presents an opposite result. The difference in participant number (32
V.S 10) could be a reason for this difference. However, in the previous study by Mylon et al. (88) the
thickness of the NBR gloves was less than that of the NRL (NRL= 0.123 mm, NBR= 0.074 mm). Thus, it
could be argued that a better comparison can be drawn from this study, due to the gloves being of
similar a thickness. Another reason could be the standardisation of finger orientation used in this
test. In the previous study, participants were not instructed on how to place their fingers onto the
test bed. Having the fingers flat would induce more accurate results through an increase in surface
contact area, and participants are more inclined to feel the bumps through increased contact area
and mechanoreceptor activation (276). When the gloves are dry, the gloves will deform to the bumps,
increasing the likelihood of mechanoreceptors picking up the change in stimuli (264). In addition, the
material stiffness may hinder the detection of the bumps. When the gloves are moving over the bump,
there will be some minor pulling of the glove as it deforms, shown in Figure 8.17. In the stiffer NBR material,
this effect will be lessened as the material is stiffer and will deform less (277). This has been explored and
discussed in terms of asperity contact in Chapter 6.
a) b)
Direction of glove travel
227
Figure 8.17 (a-b). a) Materials pulling when deformed to elicit tactile sensation b) mucin allowing the
material to glide over the bump.
When mucin contaminates the NBR gloves, the affinity of the mucin for the glove will cause some tack as
the mucin competes for interaction with the nylon and the gloves. This increases some adhesion of the
mucin to the bumps over time, improving detection rate of the bumps. However, the mucin did not allow
for better sensitivity beyond the limit of detection of the dry gloves in the NBR – both conditions had a
detection limit of 280 µm. When mucin is present on the NRL gloves, only weak interactions hold the
substance to the surface. Therefore, when in contact with the test bed, the mucin will run off the NRL and
cause flooding around the bumps. This separates the two surfaces, causing a decrease in detection, as seen
in Figure 8.17. However, it is possible there is also development of a tribofilm, as seen with the metal pins.
As the finger is run down the test bed, the mucin will change due to motion, pressure, and temperature
changes. It is possible that due to the interaction with the NRL, the mucin is pushed out at the start of the
test, but as the finger runs down the column, less mucin is present. Also, the participants ran their fingers
from side-side and up and down to determine the bumps. As this movement occurs the mucin will
experience shear thinning (278). This has the potential to increase the rate of tribofilm development, due to
less solution presence and more water evaporation, as in Figure 8.18. This could also be the reason for a
loss of detection when mucin is added to the NRL, as many of the smaller bumps felt by participants, when
wearing the dry NRL are at the top half of the board. In the NBR, the low tack film will be established earlier
as the mucin binds to the gloves, causing some possible stick-slip with the bumps, enhancing the detection
rate.
Bump test column Mucin quantity

Finger placed on Maximum mucin quantity as finger is
board at the top placed onto the board. Finger floods
the bumps = less detection of smaller
bumps
Mucin running off of the fingers and
glove is brought closer to the surface Direction
of finger
Less mucin contained by the finger travel
Finger reaches the Little to no mucin on the bottom row.

bottom Film development more likely
Figure 8.18. Representation of the mucin quantity of NRL on the bumps test board.
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8.5.5 Significance of findings
A summary table (Table 8.3) is provided to show the implications of contaminating gloves, and their
effects on performance.
Table 8.3. Performance of mucin contaminated glove performance when compared to the dry
condition.
Glove material
Test NBR NRL
Gross dexterity Increase Decrease
Fine dexterity Increase Increase
Sensitivity Increase Decrease
In Chapter 7 it was shown that contaminants, such as mucin, affected the frictional properties of the
gloves. This was expected, due to the addition of a substance that would act to serve as a lubricant,
lowering friction. This chapter has further shown the implications of that change in friction. By
lowering friction vastly, as observed with the NRL gloves, the detriment to gross dexterity is
apparent. In addition, the contaminated gloves are shown to decrease the sensitivity in NRL gloves,
which may lead to sensitivity issues, which could lead to missed lumps, small lacerations, and
damage to the skin (13). The impact of the contaminants on the NBR gloves, however, are shown to
be beneficial, increasing dexterity and sensitivity, in this case. This would suggest that, of the two
most common materials, the NBR material is a better selection for glove users, particularly in the
medical field. However, this must be interpreted with some caution. Whilst the NBR shows an
improvement over the dry condition, and the NRL, in this work, it has only been conducted on one
type of NBR glove. It may be the case that gloves which have been subjected to a different surface
finishing (such as silica dipping), will have a different surface chemistry, and therefore a different
chemical reaction to the contamination.
8.6 Conclusions
• The mucin contaminant has been shown to affect both the performance measures of
sensitivity and dexterity. Through different interactions, the results exhibited are different
between the materials.
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• Mucin has a greater affinity for the NBR gloves due to the polarity, leading to mucin-NBR
interaction. On the other hand, the NRL gloves will repel the mucin through hydrophobic
mechanisms and exhibit less interaction.
• When contaminated, the NRL gloves show a severe reduction in friction and a decreased
gross dexterity and sensitivity. NBR on the other hand, shows a smaller, but significant,
decrease in friction but an increase in performance. The development of the protein film,
however, has aided performance in the CSPDT by the way of adhesion, circumventing any
micro-slips between the glove and the tweezers, improving dexterity with both glove
materials.
• The chapter has overall shown that contaminants affect performance when medical
examination gloves are worn. If the contaminants are decreasing performance, as seen in
the NRL, then the effects could be potentially detrimental to the medical practice. On the
other hand, if there is an improvement, then understanding how the gloves are improved,
and with what particular glove films, could aid the market targeting of gloves for specific
use.
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Chapter Nine: Blood friction and synthetic development
In Chapter 7, it was shown that contaminants have a varied affinity, and reaction, to the different
glove materials. However, in Chapter 3, the respondents to the questionnaire demonstrated that
blood is the most frequent contaminant to contact the gloves, at least in a medical setting. This was
not used as a contaminant in the previous chapter due to the availability and shelf life of blood.
Therefore, this chapter will explore the use of blood in assessing how the friction of medical
examination gloves can be modified upon exposure (232). This chapter closely relates to the
frictional tasks carried out in Chapter 7. As blood is the most commonly contacted biological fluid, as
discovered in the questionnaire in Chapter 3, assessing frictional modifications of gloves is important
for understanding the conditions gloves are used in (6). To circumvent the storage and ethical issues
there is a need for a synthetic blood for use in future studies, in order to allow this to be replicable in
industrial settings. Thus, this chapter of the thesis focuses on the development of a representative
synthetic blood which may be used in industry to assess friction modification.
9.1 Introduction
Blood characterisation
Blood is a liquid connective tissue which is comprised of red blood cells (erythrocytes), white blood
cells (leukocytes), fragmented cells known as blood platelets (thrombocytes), and an extracellular
matrix, which is often referred to as plasma (279). The plasma is composed mostly of water, which
helps with the suspension of ions, proteins, and nutrients in the blood matrix. Blood tissue which
contains all of the plasma and cell components is known as ‘whole blood’ (280). The viscosity of
whole blood is found to be between the range of 1.38 and 5.84 mPa-s at 37°C (281–285), with most
of those studies placing the viscosity in the 3-4 mPa-s range. However, most of these studies mixed
anticoagulants into the blood, most commonly ethylenediamine tetraacetic acid (EDTA) to prevent
clotting. Although only a small amount is added (around 2µl per ml), there is a change in the way the
blood behaves and reacts. This is because EDTA works by chelating (removing) the calcium ions to
prevent any cross-binding in the blood, which prevents clotting. Mayer and Kiss (285) have shown
that anticoagulants added to the blood do give a small change in the viscosity. Blood was measured
at a viscosity of 3.54 mPa-s at 37°c, which, on average, dropped to 3.40 mPa-s when EDTA was
added. Reuf, Gehm, Gehm, et al. (284) made similar findings to this. Citrate can also be added
instead of EDTA, however, this does not bind as strongly to the calcium-blood complex as EDTA, thus
can be reversed with the addition of calcium. This is a much more complex method, as the citrate
needs to be added at the correct concentration and volume in order to prevent coagulation (286).
Several studies have also reported variations in the density of whole blood. Vitello, Ripper,
231
Fettiplace, et al. (287) states the density of blood is measured to be around 1043-1060 kg/m3.
Whereas Benson (288) states the density is between 1025 and 1125kg/m3. Most of the published
studies place the density of whole blood between 1025 and 1060 kg/m3 (287, 289–293).
Synthetic bloods
To better study how fluids, such as blood, affect glove material performance there is a requirement
for the development of a synthetic blood. This is to avoid the issues with storage and ethical queries
regarding using blood in research practice. Much of the research around synthetic bloods created in
the literature are based on matching the viscosity of whole blood. Where studies using bloods are
published, they use whole bovine, porcine, ovine, or equine blood (294). This is because the physical
properties of the animal blood are similar to those of whole human blood. In order to assess the
effect of blood on glove performance whole blood is required, as this is the blood which is most
likely to be contacted. Blood which has been separated into cells and plasma could also contaminate
gloves, such as that in a medical laboratory setting. Although, in more emergency clinical
applications, whole blood is most likely present. The likelihood of developing a fluid that acts exactly
like whole blood in terms of behaviour out of the body and chemical reactivity is low, due to the
variety of biological compounds constructing the tissue. Existing synthetic bloods are separated into
two areas; one of which is the medical use, focusing on the ability of oxygen to readily bind and
unbind as required (280). The second is for scientific study, mostly concerning forensics, such as
blood spatter and use for medical research regarding equipment and flow (295). These materials are
developed to mimic a specific characteristic of blood, primarily viscosity, none of which look at the
frictional properties or interactions with medical gloves.
9.2 Aim and Objectives

There are two aims to this chapter. The first aim is to identify if the presence of blood affects the
frictional properties of NBR and NRL gloves. This allows for a fundamental understanding how blood
interacts with the different glove materials, allowing an assessment of how friction is modified,
much like in Chapter 7. A previous study looking at the friction of medical gloves with blood (116) did
not state the nature of the blood which was used, nor whether the blood had been treated (e.g.
whole blood, fresh, or any if any anti-coagulants were present). In an ideal setting, the blood would
be drawn fresh, just before the frictional analysis is conducted. However, to get fresh whole blood,
without an anti-coagulant is difficult due to the rapid coagulative nature of the blood (296, 297). To
circumvent this coagulation, as mentioned, anticoagulants are normally used.
232
The second aim of this study is to develop a synthetic blood which may be used for future
studies regarding friction. As blood is contacted in various stages of the drying properties (fresh,
gelled, and dried) there are challenges with mimicking the properties of these. This work will focus
on creating a synthetic blood which is fresh (i.e. still wet without drying). In a medical situation, this
will be more representative of the blood exposed to during minor medical procedures. A variation of
sugars, stabilisers and proteins, which have been used previously to make bloods of varying
viscosities (295), and are easily obtainable and require little storage issues, were selected.
Comparisons will be drawn between the friction coefficients of the blood and the friction obtained
from the synthetics in order to assess if blood can be removed from future studies of this ilk. By
removing the tissue, this allows industries to assess frictional behaviour modification of a common
contaminant, without the need for safe storage, considerations for shelf life and ethics, or concerns
around disposal of materials.

Ethical approval was received by the Research Ethics Committee of the Department of Mechanical
Engineering, University of Sheffield (No 022733 and 022735).
9.3.1. Glove Materials

The NRL gloves were branded ‘Safetouch’ and the NBR gloves were provided by Synthomer. These
materials were the same as those used in Chapter 7 and 8, regarding contaminated glove friction
and effects on user performance.
9.3.2 Blood
Whole ovine blood was used with a citrate anti-coagulant added for this study. The blood used was
also compared to that of the fresh, whole human blood for contact angle analysis and FTIR. This was
to assess whether the initial behaviour and interaction with the different materials is the same
between the two tissues. If the behaviour is shown to be similar, this would give the further
validation to using a blood which has anti-coagulants present for future tests.
Whole blood
For the whole blood comparison, blood was drawn from the finger of one participant, (male, 28)
using an Abbott lancet kit, as seen in Figure 9.1(a). This kit consists of a spring-loaded lancet device
(10 × 1.2 cm) which is loaded with a lancet needle (0.3 cm). This is placed over the fingertips and the
button forces the lancet to pierce the skin to the depth of a few mm, drawing blood, as shown in
Figure 9.1 (b).
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a) Protective b)
Head Lancet
Figure 9.1 (a-b). a) Lancing device with protective head detached to reveal the lancet; b) blood
drawn from finger after pricking with the lancet device.
Ovine blood
Whole ovine blood was purchased commercially, with a sodium citrate anticoagulant added. This
was stored in the fridge when not in use as to prevent warming. When in use, the blood was heated
to 36-37°C in a water bath to get to physiological temperature, which is the temperature in which
fresh blood is most likely to come into contact with the gloves.
9.3.3 Synthetic blood development

Solutions were made up using methods from previously published literature looking at viscosity and
flow (295). For industry, the materials used in this study are easy to obtain, with little concern
regarding storage. There are many variations of synthetic bloods in the literature and available to
purchase commercially, however by creating variations of blood materials already tested for
viscosity, the study can easily assess which synthetic solution gives similar friction properties to that
of real whole blood. Slight variations have been made to those proposed by Millington (295) based
on availability of materials, viscosity of materials, and use of stabilising solutions to prevent mould
growth over time. Some of the constituents were used which have a similar nature to the chemicals
used by Millington (295), and the volumes adjusted accordingly. Synthetic blood solutions (SB) were
created consisting of variations of:
• Glucose syrup (Lyons)

• Glucose anhydride (α-D-Glucose, Boots)
• Glycerol (100%, Value Health)
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• Flour (plain, BeeRo)
• Methyl cellulose (Sigma Aldrich)
• Porcine gastric mucin (Sigma-Aldrich, Type II, unpurified)
• Sodium chloride (Sigma-Aldrich)
All materials were purchased commercially. Red food colouring was also added to the solutions for
aesthetic reasons, as well as adding colour to visually see the solutions on the gloves, as many were
colourless. The solutions were made up in accordance with the differences in their properties (some
solutions contained more agents which thickened the solutions or made them waterier). The
solutions were mixed together into a beaker, poured into sealed containers, and stored at room
temperature in a dark and dry area. A total of 7 solutions were developed, via mixing the ingredients
shown in Table 9.1. Solutions 1-3 were made in the first instance, with the proceeding solutions
being created based on the observations made from the initial material characteristic testing.
Table 9.1. Constituents of the SB solutions
Solution
Ingredient SB1 SB2 SB3 SB4 SB5 SB6 SB7
Glucose syrup (g) 2.25 3.75 0.25 2.25
Methyl cellulose
1.25 0.2
(g)
Sodium chloride
0.25 0.25 0.25 0.25
(g)
Glycerol (ml) 1.5 0.25 1 ½ of SB1 ¼ of SB1
Plain flour (g) 7.85 3.75
Glucose anhydride
1 1.4
(g)
Porcine gastric
0.15
mucin (Type II) (g)
DI water (ml) 44.5 30 20 44 20 40 40
Food colouring
0.5 4 0.5 2 2
(ml)
9.3.4 Properties of blood and synthetics

Density
The density of the SB solutions, and the ovine blood, were calculated using the method described in
Chapter 7 (Section 7.3.5). Density was measured by weighing 1 ml of each solution (Analytical
Sartorius, ±0.0001 g). The density was then determined using equation 7.2. This test was repeated
three times for each of the solutions.
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Viscosity
To measure the viscosity of the SB solutions and the ovine blood, 10 ml of each solution was
measured with a vibro-viscometer (AND, SV-1A, ±0.01 mPa-s.), discussed in Chapter 7 (see Section
7.3.2). Each solution was measured three times to obtain an average viscosity. Each sample was
shaken for one minute, before filling the sample well, to disperse colloidal suspensions and induce
homogeneity.
pH measurement
The pH of the developed SB was monitored using HANNA benchtop pH meter (HI-2211, ±0.01 pH).
The glass probe was inserted into each solution and left to reach a pH balance reading, which was
then recorded. This test was conducted only once due to the high sensitivity and availability of the
equipment.
9.3.5 Contact angles
Contact angles were measured to compare the surface interaction of the SBs, and both the fresh
whole blood, and the anti-coagulated ovine blood. Sections of the NBR and NRL gloves were cut off
and placed onto the stretching device used in Chapter 4 (Section 4.3.1) to flatten the material and
secure it in place. Contact angles were measured via a contact angle goniometer (ramé-hart, model
100-06) using the sessile drop method used in Chapter 4 (Section 4.3.1). The previous work also
showed that the contact angle is unaffected by the strain of the material. Thus, the material was
studied in the ‘unstrained’ condition.
9.3.6 FTIR
FTIR (described in Chapter 5, Section 5.3.1) was used to assess whether binding to the gloves was
similar between the ovine and the whole blood samples. Whole human blood (0.4 ml, acquired by
the lancing device in Figure 9.1), and ovine blood (0.4 ml) was syringed onto the NRL and NBR gloves,
separately (4 samples in total). The samples were left to dry for 30 minutes before washing the
solutions in DI water. The gloves were then scanned on the FTIR (Thermo Scientific, Nicolet iS5) in
the 4000-600 cm-1 region with a scanning resolution of 4cm-1. Three samples of each glove and each
blood source were obtained (12 scans in total).
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9.3.7 Friction measurements
Anwer (116) previously analysed the friction coefficients of blood on a scalpel handle with a serrated
surface on both the flat and serrated section. However, scalpels come with a variety of serrated
patterns. In many cases, these patterns contain large areas of smoother material where fingers are
placed. Therefore, for consistency and comparison to the previous work conducted in this thesis, the
friction was measured using a polished steel strip, which was used to represent smooth metal in the
medical profession (bedpans, smooth medical tools, trolleys etc.) and the pegboard pins in Chapters
6 and 8.
As with the previous tests (see Chapter 6 and 7), the gloved index finger pad of the sole
participant (male, aged 28) was placed onto the metal strip (attached to the AMTI force plate using
double sided tape) at a 40° angle. The finger was held for 2-3 seconds at the desired force before it
was moved down the strip. The forces used were chosen based on the grasping forces discussed and
used in previous chapters, with target loads of 1, 2, 3, 4 and 5 N (189). The static friction was
assessed for this work, as this is considered more relevant to studies of this ilk with medical
examination gloves (114, 116). The friction assessments were carried out on the ovine blood and the
synthetic bloods only. The fresh blood volume obtained from the lancing device was not enough to
carry out frictional assessments, as previously stated.
Blood and SB deposition
Contaminants were deposited in the same manner as in Chapter 7, whereby the finger was placed
into the solution, up to the proximal-intermediate interphalangeal joint, for 10 seconds (Figure 9.2).
Prior to putting the finger into the glove, the glove was ensured to fit around the finger, meaning no
loose material was present. The finger was then removed, the excess shaken off and the friction
analysis conducted. All contaminants were tested at room temperature (23.1-24.8°C), with the
exception of the blood, which was heated to physiological temperature 37°C (±1.5) via a water bath
and monitored with an infrared thermometer (Raytek, RSCMTFSU ±0.5°C).
237
Figure 9.2. Application of solutions to the glove materials
Weight deposited
The mass transfer of blood was measured by analysing the weight transferred to the glove. The
gloves were weighed using a 5 point balance (Analytical Sartorius ±0.0001 g) and then the blood was
applied following the application method. The gloves were then weighed again to determine the
mass. Three of each glove were assessed with each SB and the ovine blood. As is visible from the
image in Figure 9.3, the distribution of blood onto the glove is not homogenous, i.e. the blood pools
in some areas and is thinner in others. Therefore, the film thickness has not been calculated (as in
Chapter 7) due to the visually uneven dispersion.
Figure 9.3. Blood deposited onto the finger
Temperature changes
As with the mucin in Chapter 7, the blood was measured for changes in temperature when removed
from the water bath once transferred to the finger. This was measured five times to obtain an
average. The temperature was found to drop to an average of 34.6 (±0.32) °C. As with the mucin
used previously in Chapters 7 and 8, the proteins in blood are sensitive to heat and the interactions
with their surroundings (290, 296, 298). Thus heating beyond physiological temperature may have
238
changed some of these interactions with the glove materials, leading to differences in bonding,
triboelectric interactions, and drying properties (299). Furthermore, in scenarios where blood has
contaminated medical examination gloves, the blood has usually already left the body. Thus, it will
have dropped in temperature, as seen in this study, whereas the physiological temperature would
be more appropriate to maintain when assessing surgical gloves, as the gloves are likely to be in a
more temperature regulated and controlled environment.
Drying
In order to assess the drying efficacy, 0.5 ml of blood was syringed onto sections (approx. 5.0 × 5.0
cm) of the glove materials and rubbed with the syringe to spread the sample. This was weighed and
then left to dry on the weighing scales (Analytical Sartorius ±0.0001 g), with the weight taken every
30 seconds to assess the drying time over 5 minutes. This was carried out 5 times for each material.
9.3.8. Statistical analysis

In order to assess the similarities of each synthetic sample to the ovine blood, two-tailed paired t-
tests were performed on the CoFs at each of the target loads (300). The null hypothesis states that
no differences exist between the SB and the blood. Therefore, a p-value greater than .05 shows that
there is no evidence of a difference between the SB friction and the whole ovine blood. T-tests were
also carried out on the contact angles of human blood and ovine blood to assess how similar the
initial contact behaviour is between the two.
9.4 Results
9.4.1 FTIR
The spectra of the human and ovine bloods are shown in Figure 9.4 with NBR and Figure 9.5 with
NRL. As is visible there are changes present to the spectra between the clean, uncontaminated NBR
and the blood contaminated NBR. Major changes to functional groups and peak absorbances have
been highlighted on both figures. There are some minor absorbance differences between the two
blood types on both glove materials, but the results show very similar spectral patterns, indicating
that in both materials, similar changes also occur. When blood is present in both glove materials the
amide (NH) peaks around 6340-6390 cm-1 disappear, and a stronger presence of the hydroxyl (OH) is
noted in the broad peaks at 3500-3150 cm-1. A carbonyl (C=O)/Diene (C=C) peak is also present when
blood has contaminated the surface of both materials at around 1650 cm-1. The presence of two
peaks at 1575-1540 cm-1 indicates amide C=C stretching. However, this noticeably then becomes one
peak when contaminated with blood, indicating the presence of a carboxylate (COO-) around the
239
1540 cm-1 wavelength. The final major peak change is seen with the dissolution of the ester C-O-R)
stretching/Aliphatic amine (C-N) peaks present around the 1052-1010 cm-1 region when the gloves
are contaminated with blood (209, 210, 265). The peaks present around the 2360-2340 cm-1 region
indicate the presence of CO2 in the atmosphere and are not regarded as changes to the surface in
these results. The changes in spectra show that blood has either bound to the surface chemically or
chemically modified the surface. After washing both of the materials, the gloves were found to have
discoloured, thus it is likely that blood has bound to the surface and cannot be washed off.
Figure 9.4. FTIR spectra of the NBR gloves and gloves contaminated with ovine and human blood
Figure 9.5. FTIR spectra of the NRL gloves and gloves contaminated with ovine and human blood
240
9.4.2 Material characterisation
The first SB formed (SB1) formed a rigid gel-like substance. This rendered the material unusable for
the purposes of this experiment, thus no testing has occurred using SB1. However, the substance
was further diluted to make a 6th and 7th synthetic blood (SB6 and SB7), as described in the
methodology (Table 9.1). The overall results of the density measurements, pH, and contact angles
are shown in Table 9.2. As can be seen similar results are observed for the pH of the solutions.
Putting them in the neutral range, with slightly basic properties, which is similar to that observed
with the blood.
Table 9.2. Properties of the synthetic bloods and blood. Red cells indicate the results that are not
close to blood. Amber indicates results which are close to that of blood, and green indicates little to
no difference with blood.
𝝆 η Contact Angle (°)

Solution pH
(kg/m3) (mPa-s) NBR NRL
SB1 7.19 Solution formed a thick gel – unsuitable for further testing
1071.90 6.49 42.67 135.67
SB2 7.27
(±1.32) (±0.03) (±8.74) (±10.26)
1010.99 1.45 43.00 107.67
SB3 7.29
(±0.37) (±0.03) (±10.15) (±6.11)
1031.85 1.18 26.33 122.33
SB4 7.25
(±0.17) (±0.01) (±2.08) (±4.36)
1043.62 3.67 43.67 97.00
SB5 7.32
(±2.47) (±0.00) (±1.53) (±3.06)
1035.57 3.45 37.33 125.00
SB6 7.29
(±0.17) (±0.04) (±7.57) (±12.53)
1030.51 2.98 33.00 102.90
SB7 7.22
(±0.11) (±0.01) (±2.65) (±6.28)
1052.38 3.38 32.00 95.00
Whole Ovine Blood Δ 7.31
(±2.15) (±0.00) (±4.92) (±9.18)
33.00 92.00
Whole Human Blood 7.35-7.45* 1025-1060* 3.00-4.00*
(±2.65) (±11.87)
Δ = testing carried out at 37°C. ± indicates standard deviation. *averages obtained from literature
Density
The density of each of the samples is shown in Figure 9.6. The results show that SB2 (ρ= 1071.90 ±
0.17 kg/m3) and SB3 (ρ= 1010.99 ± 0.37 kg/m3) do not fit into the density range of the blood
provided in the literature (shown in faded red on Figure 9.6). However, there is little variation in the
density between the SB4, SB6, and SB7. The closest match of density to the ovine blood is SB5,
which is also the only SB to have no significant difference to the blood following a paired t-test
(t(2)=-1.010, p=.158, Table 9.3).
241
1080
1070
1060
1050
Density (kg/m3)
1040
1030
1020
1010
1000
SB2 SB3 SB4 SB5 SB6 SB7 Ovine Blood
Sample
Figure 9.6. Density of synthetic bloods and ovine blood. Opaque red band indicates density range of
whole human blood in the literature. Error bars denote standard deviation.
Table 9.3. Paired t-tests, comparing the developed SB to the measured ovine density.
Sample t-test
t(2)=8.149
SB2
p=.001*
t(2)=-20.990
SB3
p=<.001*
t(2)=-9.837
SB4
p=.006*
t(2)=-1.010
SB5
p=.158*
t(2)=-7.626
SB6
p=<.001*
t(2)=-10.740
SB7
p=.001*
*indicates statistically significant differences (p<.05)
Viscosity
The viscosities between the solutions have some differences (Figure 9.7). The solutions range from
6.49 to 1.18 mPa-s within a temperature range between 23.1-23.5°C. The results indicate that SB2 is
the most viscous of the solutions at 6.45 (±0.03) mPa-s. This is likely due to the amount of flour
present in the solution. The samples were homogenised by mixing/shaking. However, in this
solution, it was found that the suspended flour quickly settled to the bottom of the mixture. The
average reported viscosity of whole blood is reported to be between 3-4 mPa-s, which is highlighted
on the graph in Figure 9.7. Only SB5 (3.67 ±0.00 mPa-s) and SB6 (3.45 ±0.04 mPa-s) fall into the
242
average viscosity range of blood, whilst SB7 is on the verge at 2.98 mPa-s (±0.01). Although, none of
the viscosities measured show statistical similarities to the ovine blood, SB5, SB6 and SB7 all show
similar results to the ovine blood (p<.05, Table 9.4).
6
Viscosity (mPa-s)
0
SB 2 SB 3 SB 4 SB 5 SB 6 SB 7 Ovine Blood
Sample
Figure 9.7. Viscosity of synthetic bloods and ovine blood. Opaque red band indicates viscosity range
of blood in the literature. Error bars denote standard deviation.
Table 9.4. Paired t-tests, comparing the developed SB to the measured ovine viscosities.
Sample t-test
t(2)=-230.409
SB2
p=<.001*
t(2)=140.750
SB3
p=<.001*
t(2)=288.900
SB4
p=<.001*
t(2)=-37.123
SB5
p=<.001*
t(2)=-7.506
SB6
p=.016*
t(2)=40.442
SB7
p=.001*
* indicates statistically significant differences (p<.05)
Contact angles
The results for contact angles with the SB, ovine and human blood are shown in Figure 9.8. When whole
human blood was exposed to the NBR surface, there is a good surface wettability with an average contact
angle of 32.78° (±1.79). An example of SB4 in contact with the NBR is shown in Figure 9.9 (a). When in
contact with NRL, there is a lower surface wettability with an angle of 92.0° (±11.87). An example of SB5 in
contact with the NRL is shown in Figure 9.9 (b). The results obtained from the ovine blood have similar
contact angles, and no statistically significant differences are shown between the two samples with human
243
blood (NRL t(2)=0.451, p=.949 ; NBR t(2)=0.707, p=.816). The SBs show similarities through their results in
the NBR samples, with the exception of SB4 which has a lower contact angle on average (26.3° (±2.08)). As
this solution contains flour, the solution has become colloidal, with suspended particulates of flour,
this could affect the contact angle of the solution with the gloves. However, SB2 contains more flour
than SB4, but does not exhibit the same behaviour. When applied to NBR, SB4 and SB7 have a
similar contact angles to real blood at 33.0° (±4.92). When applied to NRL, SB5 (97.00° (±9.18) and
SB7 (102.90° (±6.28)) have similar contact angles to ovine blood at 95.00° (±9.18). Paired t-tests
show no statistical differences to any of the contact angles with the ovine blood for both materials
(p>.05, Table 9.5). However, a significant difference is found between SB5 (43.66°) and the ovine
blood in the NBR material (t(2)=-6.407, p=.007).
160
140
120
Contact Angle
100
80
NBR
60
NRL
40
20
0
SB2 SB3 SB4 SB5 SB6 SB7 Human Ovine
Blood Blood
Blood
Figure 9.8. Contact angles of synthetic bloods, ovine blood, and human blood. Error bars denote
standard deviation.
a) b)
Figure 9.9 (a-b). Contact angles of a) NBR and b) NRL. The lower contact angle in NBR indicates a
surface with hydrophilic properties whilst the NRL indicates hydrophobic with high contact angles, as
observed with all of the synthetic bloods.
244
Table 9.5. Paired t-tests, comparing the developed SB to the measured ovine contact angles as well
as comparing the human to the ovine blood.
Glove t-test
Sample
NBR NRL
t(2)=-1.834 t(2)=-3.919
SB2
p=.279 p=.055
t(2)=-1.651 t(2)=-0.841
SB3
p=.161 p=.551
t(2)=-1.546 t(2)=-6.146
SB4
p=.135 p=.042
t(2)=-6.407 t(2)=-2.377
SB5
p=.007* p=.134
t(2)=-0.935 t(2)=-2.284
SB6
p=.520 p=.134
t(2)=-0.621 t(2)=-1.011
SB7
p=.686 p=.992
t(2)=0.707 t(2)=0.451
Human blood
p=.816 p=.949
*indicates statistically significant differences
Deposited material
The amount of each SB and blood deposited onto both glove materials, following the application
method, is shown in Figure 9.10. Similar amounts of the blood and SB’s are deposited onto both of
the glove materials. NRL is shown to have slightly less of each solution transferred to the gloves,
which was also noted in Chapter 7 and 8. The average amount deposited for all SBs onto the NBR is
0.101 (±0.006) g, whereas the NRL was found to have 0.089 (±0.008) g deposited. The largest noted
difference between the two materials is with SB4. As SB4 was a suspension of flour in a sugar
solution, this could have been due to the amount of flour getting stuck to the glove material. In the
NBR, 0.097 (±0.005) g was found to stick to the glove, whereas 0.076 (±0.012) g was found on the
NBR. More ovine blood was also found on the NBR (0.090 (±0.01) g) when compared to the NRL
(0.073 (±0.004) g). Statistically significant differences are not found between the weight of blood and
the weight of solutions SB4, SB5, SB6, and SB7 when on the NBR material (p>.05, Table 9.6). SB4
shows no statistically significant difference to the blood deposition when on the NRL (t(2)=0.561,
p=.494).
245
0.12
0.1
0.08
Mass (g)
0.06
NBR
0.04
NRL
0.02
0
SB2 SB3 SB4 SB5 SB6 SB7 Ovine
Blood
Sample
Figure 9.10. Amount of SB, and blood deposited onto the NBR and NRL glove materials. Error bars
denote standard deviation.
Table 9.6. Paired t-tests results of weight deposition between ovine blood and each synthetic blood.
Glove t-test
Sample
NBR NRL
t(2)=-3.595 t(2)=-4.627
SB2
p=.024* p=.013*
t(2)=-3.211 t(2)=-5.208
SB3
p=.032* p=.002*
t(2)=-1.383 t(2)=-0.561
SB4
p=.282 p=.494
t(2)=-1.018 t(2)=-3.736
SB5
p=.452 p=.001*
t(2)=-1.174 t(2)=-5.476
SB6
p=.365 p=.003*
t(2)=-2.264 t(2)=-4.477
SB7
p=.168 p=.020*
*indicates statistically significant differences
Drying
The results of blood drying show similar rates of evaporation for each of the materials (Figure 9.11),
with the NBR having a slightly higher evaporation rate than the NRL. On average, the NBR has a
weight loss of 0.06412 (±0.00199) g every 30 seconds, whereas the NRL lost an average of 0.05429
(±0.00123) g every 30 seconds.
246
0.1
0.09
0.08
0.07
Blood weight loss (g)
0.06
0.05
NBR
0.04
NRL
0.03
0.02
0.01
0
0 50 100 150 200 250 300
Time (s)
Figure 9.11. Evaporation of blood from the surface of the NRL and NBR materials
9.4.3 Friction
Resultant horizontal force and power fit laws were fitted to the data, and CoFs were calculated as
per the preceding chapters in this thesis, using the equations in Chapter 4 (see equations 4.2-4.4)
9.4.3.1 NBR
Blood
An example of the raw data for the NBR with blood is shown in Figure 9.12. The friction results
obtained from the uncontaminated NBR gloves are shown in Figures 9.13 (a-b) along with the blood
contaminated glove friction. The addition of blood produces lower CoFs than for the dry condition.
When contaminated, the behaviour is similar to the dry condition across the loads, as the CoF ranges
between 0.72-0.67. The dry condition does, however, show a slight trend of increasing CoF as the
load increases, which does not occur when the gloves are contaminated with the ovine blood (µ
ranges 1.10-1.01 when dry). The decrease in friction is significantly different across each load
following paired t-tests (1N t(2)=3.318, p=.081; 2N t(2)=0.917, p=.935; 3N t(2)=-2.553, p=.125; 4N
t(2)=-2.886, p=.102; 5N t(2)=0.934, p=.449).
247
5
4.5
4
3.5
Force (N)
3
2.5
2 Normal force
1.5 Horizontal force
1
0.5
0
0 1 2 3 4 5 6 7 8
Time (s)
Figure 9.12. Normal and Horizontal force of the NBR glove contaminated with ovine blood at the 4 N
target load on smooth steel.
a) 7 b) 1.4
6
1.2
Static friction force (N)
5 1.0
4 0.8
Static CoF
NBR
3 0.6 NBR
2 0.4
1 0.2
0 0.0
0.0 2.0 4.0 6.0 0.0 2.0 4.0 6.0
Figure 9.13 (a-b). Static friction (a) and CoFs (b) for dry NBR gloves and NBR gloves when
contaminated with ovine blood on smooth steel. Error bars denote standard deviation.
Synthetic validation
The static friction of the NBR gloves when contaminated with the SB’s and the ovine blood are
shown in Figure 9.14 (a-b). SB3 has a consistently higher CoF on average across all of the loads when
compared to the ovine blood sample. SB6 is higher at the 1 N load, and then lower as the load
increases. SB5 and SB6 show similar trends in decreasing CoF over the increased load, whereas SB2
is the only solution which is shown to increase CoF over the load range. The CoF of SB4 also
increases, however there is a decrease in CoF initially (1 N µ= 0.79 ±0.02; 3 N µ= 0.52 ±0.01; 5 N µ=
0.66 ±0.01). At the 1 N load SB4 (µ= 0.79 ±0.02) and SB7 (µ= 0.75 ±0.01) produce similar CoFs to the
ovine blood (µ= 0.73 ±0.02). SB7 has similar CoFs to the ovine blood, exhibiting little friction
248
differences across the range of loads. Due to the similarity in results, only SB7 has been tested for
statistical significance (Table 9.7). The t-tests shows no significant differences between the blood
and SB7, indicating similar CoFs at each of the target loads.
4.0 1.2
a) b)
3.5
1.0
3.0
Static Friction Force (N)
SB2 0.8 SB 2
2.5 SB 3
SB3
CoF
2.0 SB4 0.6 SB 4
SB5 SB 5
1.5
SB6 0.4 SB 6
1.0 SB7 SB 7
0.2 Blood
0.5 Blood
0.0 0.0
0 2 4 6 0 2 4 6
Figure 9.14 (a-b). Static friction (a) and CoFs (b) for dry NBR gloves when contaminated with
synthetic bloods and ovine blood. Error bars denote standard deviation.
Table 9.7. Static CoFs obtained from SB7 and whole ovine blood with paired t-test results with NBR
SB7 Blood
CoF t-test
Load (N) CoF Load (N) CoF
1.04 0.75 1.03 0.73 t(2)=0.142
(±0.04) (±0.02) (±0.07) (±0.01) p=.901
2.14 0.68 1.99 0.69 t(2)=1.634
(±0.04) (±0.04) (±0.14) (±0.01) p=.243
3.04 0.67 3.28 0.68 t(2)=-3.745
(±0.01) (±0.01) (±0.10) (±0.01) p=.065
4.09 0.67 4.19 0.69 t(2)=0.967
(±0.07) (±0.07) (±0.06) (±0.01) p=.436
5.31 0.68 5.15 0.70 t(2)=2.702
(±0.11) (±0.09) (±0.04) (±0.02) p=.114
The 1N force is the force most observed with grasping and holding equipment lightly, therefore it
could be considered more important that the friction at the 1N force needs to be similar between
the synthetic and the blood (218). Figure 9.15 highlights the similarity in friction between SB7 and
the ovine blood at the 1N target load. No statistical difference is found between the CoFs with SB7
249
showing a CoF of 0.75 (±0.01) and blood showing a CoF of 0.73 (±0.02). As shown in Table 9.7, the
results are statistically similar following a paired t-test (t(2)=0.142, p=.901).
0.8
0.7
0.6
CoF at 1 N
0.5
0.4
0.3
0.2
0.1
0.0
SB7 Blood
Substance
Figure 9.15. Comparison of the Static CoF at the 1 N target load for SB7 and ovine blood. Error bars
denote standard deviation.
9.4.3.2 NRL
Blood
An example of the raw data for the NBR with blood is shown in Figure 9.16. The results comparing
the dry NRL to the blood contaminated NRL are shown in Figure 9.17 (a-b). As with the NBR, the NRL
is shown to decrease in friction. However, the decrease is far greater than observed in the NBR. This
was also noted with the mucin protein used in Chapter 7. When blood is applied, the CoF is shown to
be significantly greater (p<.05) than the dry condition between all of the loads. The greatest
difference is observed between the 1N target loads. The CoF is shown to decrease by 1.44 when the
gloves are contaminated by blood (dry µ= 2.15 ±0.02; blood µ= 0.71 ±0.01, p=<.001). As the load
increases the CoF of the blood decreases slightly to 0.50 ±0.01. The CoF at all loads is shown to be
significantly different (1N t(2)=-64.246, p=<.001; 2N t(2)=-75.466, p=<.001; 3N t(2)=-238.713,
p=<.001; 4N t(2)=-199.080, p=<.001; 5N t(2)=-331.705, p=<.001).
250
5
4.5
4
3.5
Force (N)
3
2.5
Normal force
2
1.5 Horizontal force
1
0.5
0
0 1 2 3 4 5 6 7 8
Time (s)
Figure 9.16. Normal and horizontal force of the NRL glove contaminated with ovine blood at the 4 N
target load on smooth steel.
a) 8.0 b) 2.4
7.0
2.0
6.0
Friction Force (N)
1.6
5.0
CoF
4.0 1.2
NRL NRL
3.0 Blood NRL Blood
0.8
2.0
0.4
1.0
0.0 0.0
0.0 2.0 4.0 6.0 0.0 2.0 4.0 6.0
Normal Force (N) Normal force (N)
Figure 9.17 (a-b). Static friction (a) and CoFs (b) for dry NRL gloves and NRL gloves when
contaminated with ovine blood on smooth steel. Error bars denote standard deviation.
Synthetic validation
The static friction results of NRL gloves are shown in Figure 9.18 (a-b). Noticeably the friction of the
solutions is higher with NRL than with NBR. SB7 shows a sustained higher friction than all of the
other SBs, with the exception of SB3 at the 1N load (SB3 µ= 1.82 ±0.01; blood µ= 1.69 ±0.01). With
the exception of SB2, which behaved similar to the NBR material, and SB6, all SBs showed a trend of
decreasing CoF with an increase in load. SB7 shows a sustained higher friction than all of the other
SBs, with the exception of SB3 at the 1N load (SB3 µ= 1.82 ±0.01; blood µ= 1.69 ±0.01). Overall blood
produces a lower CoF than the other SB’s except for SB2 at 1 N (SB2 µ= 0.61 ±0.11; blood µ= 0.71
±0.05). This similarity was found to be statistically similar (t(2)= 1.593, p=.204, Table 9.8). Statistical
251
significance was found at each of the other loads (2-5 N, p<.05, Table 9.8). SB3 at 5 N has a similar
CoF to the blood at 5 N (SB3 µ= 0.60 ±0.01; blood µ= 0.51 ±0.04), however this is statistically
different (t(2)=-11.269, p=<.001). With the exception of SB2, which behaved similar to the NBR
material, and SB6, all SBs had a trend of decreasing friction with an increase in load. SB7 shows a
sustained higher friction than all of the other SBs, with the exception of SB3 at the 1N load (SB3 µ=
1.82 ±0.01; blood µ= 1.69 ±0.01).
a) 8
b) 2.0
7 1.8
1.6
6
Static friction force (N)
SB2 1.4
5 SB 2
SB3 1.2
Static CoF
SB 3
4 SB4 1.0 SB 4
SB5 0.8
3 SB 5
SB6
0.6 SB 6
2 SB7
0.4 SB 7
Blood
1 Blood
0.2
0 0.0
0 2 4 6 0 2 4 6
Figure 9.18 (a-b). Static friction (a) and CoFs (a) for dry NRL gloves when contaminated with
synthetic bloods and ovine blood. Error bars denote standard deviation.
Table 9.8. CoFs obtained from SB2 and whole ovine blood with paired t-test results with NRL
SB2 Blood
CoF t-test
Load CoF Load CoF
1.18 0.61 1.12 0.71 t(2)=1.593
(±0.14) (±0.09) (±0.05) (±0.02) p=.204
2.20 0.90 2.23 0.73 t(2)=-96.190
(±0.05) (±0.03) (±0.04) (±0.05) p=<.001*
3.12 0.85 3.18 0.64 t(2)=-44.715
(±0.11) (±0.01) (±0.04) (±0.01) p=<.001*
4.18 0.78 4.25 0.56 t(2)=-24.545
(±0.21) (±0.02) (0.04) (±0.02) p=<.001*
5.13 0.72 5.27 0.51 t(2)=-47.039
(±0.11) (±0.01) (0.07) (±0.04) p=<.001*
± denotes standard deviation *indicates statistically significant differences
As with the NBR, focus should be placed around the 1 N load, for easier comparison. Figure 9.19
highlights the similarity in friction between SB2 and the ovine blood at the 1N target load. No
statistical difference is found between the CoFs with SB2 showing a CoF of 0.61 (±0.11) and blood
252
showing a CoF of 0.73 (±0.02). As shown in Table 9.7, the results are statistically similar (t(2)=1.593,
p=.204).
0.8
0.7
0.6
0.5
CoF a 1N
0.4
0.3
0.2
0.1
0
SB2 Blood
Substance
Figure 9.19. Comparison of the Static CoF at the 1 N target load for SB2 and ovine blood with NRL.
9.5 Discussion
9.5.1 Whole human and citrated blood
Many minor procedures exist where anti-coagulants are provided (301). Therefore, a part of this
study was aimed at assessing if the chemical behaviour was the same between whole blood and
anti-coagulated blood upon contact with the glove materials. The results indicate that the contact
and reactions are similar between the two whole bloods used. The FTIR shows similar spectra for
both the ovine and human blood in both NRL and NBR. This is likely due to the fact that the
components of blood which are interacting with the gloves are the same for both samples, thus the
spectra are similar. There is evidence of some sustained differences on the gloves surface once
exposed to blood. These changes appear to be more prevalent in the NRL, as indicated by the
greater differences in absorbances, likely to be because of blood protein and latex protein residue
interactions. The initial contact of the bloods on the gloves also shows similar angles for both the
NRL and NBR materials. It is shown that for this study, the chemical interactions between the blood
and the glove are not dependent on the presence of an anti-coagulant. This means using the
anticoagulated blood reflects the initial interactions that would be seen in a clinical situation.
9.5.2 Effects of blood on glove friction

The results obtained from the NRL gloves reflect those from the study by Anwer (116), which
showed the friction increased by 0.2 when blood was applied to NRL gloves. The results of this study
253
also show a decrease in friction, showing that at 1 N, the CoF decreases by 1.44. Although, at the
higher loads, the material will conform and bend more, causing a difference in the way the materials
both contact the surface, and behave under that load, which has been shown and discussed in
Chapter 6. Anwer (116) used greater forces for their study with blood, which led to a lot of
fluctuation in the applied load (between 22.8 and 35.3 N). This fluctuation is most likely due to the
extraordinary amount of pressure being placed onto one finger. This in unlikely to happen in
surgeries, as the load applied will be spread across the fingers holding the tool, and not applied to
one particular area.
As detailed in Chapter 6, the nature of the glove is important to their function, and when
drawing comparisons between studies. The gloves used by Anwer (116) were only declared as NRL
gloves. No information was present on whether the gloves were examination or surgical, nor how
well the glove fit the finger. The study also set out to compare double gloves to single glove use
when contaminated, which would imply that the gloves were surgical as double gloving is most likely
to be used here (133). A question around this research has been that if blood can be used for friction
tests, should it be fresh whole blood, most commonly encountered in minor wounds, or blood with
an anti-coagulant, more often encountered in surgeries and minor procedures (301)? Unfortunately,
as discussed, no fresh whole blood was available for the friction assessments, it is unable to
ascertain if major differences would be between present between anti-coagulated and fresh blood.
It is certain that the blood will dry and clot upon exposure to the atmosphere, thus friction changes
will likely occur (296). What this work does show, however, is that blood decreases friction in both
glove materials in very different ways, as observed in Chapter 7 with the other contaminants used.
Blood-glove material interactions
The differences in frictional behaviour are more observable as the loads increase. At the 1 N load,
the gloves have similar frictional properties when contaminated by the blood (0.71 for NRL and 0.73
for NBR). As revealed in Chapter 7, both the affinity of the contaminant for the gloves, and the
electrostatic interactions, both play a pivotal role in the frictional properties of contaminated glove
materials. Much like the contaminants used in Chapter 7, this study has shown that the blood has a
higher affinity for the NBR, and a lower affinity for the NRL. This is exhibited by the contact angle of
blood on the NRL being greater than 90° and then when being exposed to the NBR, the contact angle
is less than 90° (302). As blood is a tissue composed of many individual components, each with their
own affinity and aversion to the materials further interactions complicate the frictional properties.
Protein affinity will change and compete with weak electrostatic interactions depending on the
254
environment, which make it difficult to determine exactly what is happening over the course of the
changing loads (136).
Electrostatic and chemical interaction
As with the contaminants used in Chapter 7, and the water in in Chapters 4 and 5, blood will form
capillary bridges, induced by electrostatic interactions, between the metal counter-face and the
gloves. Oliver and Barnard (303) showed that the charges on blood are strongly influenced by the
blood electrolytes, which in turn will influence the overall charges, and thus, the attraction to the
different glove materials. Therefore, the effects of the electrostatic charges play an important part in
the lubrication and adhesion processes with blood. Blood has been shown to have a varied charge
depending on how it is suspended and the environment. Overall, the general charge on blood is
negative (298, 304). However, constituents of blood possess some positive charges (such as the
haemoglobin protein (305)), which are dependent upon the surroundings of the molecules (such as
ions, dissolved gases etc.) (306). Although the proteins and constituents are different, the blood
proteins will behave very similarly to the mucin proteins. That is to say, as noted with the mucin in
Chapters 7 and 8, charge repulsion and charge attraction play a major role in how blood will bind to
the gloves and cause changes in frictional properties.
Also previously discussed in Chapter 7, the triboelectric series places NRL as a negatively
charged species and NBR as a positively charged species (14, 248). Therefore, more migration of the
blood will occur towards the NBR material, which is seen by the contact angle and surface wetting as
well as the higher mass being deposited onto the glove material. In the performance tests carried
out in Chapter 8 with the mucin, this aided the dexterity and sensitivity. As the drying properties of
blood are different, and tend to form gels which have greater tack than the mucin (297), it would be
prudent to assume the same increase in performance would be present. But it can be presumed that
differences in performance measures when different glove materials are contaminated with blood
would be apparent, as this has been previously observed with the mucin protein in Chapter 8. It is,
however, important to note that in both materials, the CoF drops to around 0.6-0.75 in both
material, therefore it is possible that the presence of blood is similar, regardless of the glove
material being used. This suggests the lubrication of the blood is an important factor, not just the
chemical interaction. This means that a single synthetic blood being developed needs to be good
enough to pick up the minor differences which exist between the friction with the two materials.
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Blood drying and evaporation
In emergency situations where blood is present, there is likely to be dried blood already present
which may not contaminate the gloves. However, once the wet blood has contacted the gloves, the
probability of that blood drying is high. The drying property is also a function of the coagulation of
the blood, which begins to occur once the blood has been exposed to a different environment. In
coagulation, the fibrin proteins cross-link and form harder, solidified structures whilst the
evaporation of water causes platelet adhesion and aggregation. This leads to gelation, and then
solidification of the blood material (307). Laan, Smith, Nicloux, et al. (296) shows that, when blood
pools, the substance undergoes two drying stages. The first of which is where the evaporation rate
of the water increases towards zero. In the second stage, the liquid/gel diffuses the vapour to the
surface of the material. Subsequently, the blood dries out and becomes a sticky gel, before
becoming a solid mass through further evaporation. However, the study was looking at blood
pooling, rather than smaller amounts of blood already applied to a surface. It is reasonable to think
that since the blood is present in a smaller, thinner layer on the surface of the glove material, the
drying process would be quicker in the study conducted here. Nonetheless, the drying process is
slower at standard room temperature when compared to extreme conditions, thus is not likely to
have a great affect in this friction study (297).
The reason for the difference in evaporation rate could be due to the affinity of the blood
for the NBR surface, which could push the water to the surface, inducing a quicker evaporation than
that seen with the NRL (296, 307). In standard examinations, where the gloves are exposed to blood,
there is a greater likelihood that over time the frictional properties will change, due to the gelation,
evaporation and ultimately drying of the blood. Neither this study, or the study by Anwer (116),
looked into the effects of this. This study is looking more at examination gloves, which are more
likely to be changed before the blood fully gels and turns into a tacky film. However, this depends on
the volume of blood and the procedures involved, so may be of relevance for future work. The
synthetic bloods developed will also undergo some evaporation, however, this was not explored
here as the main constituent is water, so it was thought the evaporation would have less of an effect
over the course of these studies.
9.5.3 Protein behaviour with gloves

Given that mucin and blood are both protein based substances, it is also important to compare the
results from this chapter, and those observed in Chapter 7 when the gloves were contaminated by
mucin. Although there are some differences, which are shown in Figures 9.20 (a-b), there are also
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similarities in the pattern of behaviour between the blood and mucin. At the 1 N target force, CoFs
are shown to be similar between the two substances on both materials. This has been highlighted in
the bar graph in Figure 9.21. The similarities in behaviour are likely to be due to the resemblances
with the interaction. Both mucin and blood are primarily composed of water and proteins (234, 279).
This strongly implies that the protein interaction and attraction/repulsion is of significance when
studying the friction properties. Further work should be conducted looking at a range of protein
based contaminants to fully understand the behaviour of the proteins under the load range. It does
appear that at the lower load, more representative of a grasp force (189), a similar behaviour and
friction coefficients are observed between the two materials with the proteins. It may be that the
protein behaviour is similar when exposed to each material, which leads to a similar friction
behaviour across the range of bodily fluids of the same ilk.
a) NBR Blood NBR Mucin b) NRL Blood NRL Mucin
0.9 0.9
0.8 0.8
0.7 0.7
0.6 0.6
0.5 0.5
CoF
CoF
0.4 0.4
0.3 0.3
0.2 0.2
0.1 0.1
0.0 0.0
0 2 4 6 0 2 4 6
Load (N) Load (N)
Figure 9.20 (a-b). Friction of blood and mucin over the 1-5 N load range with NBR (a) and NRL (b).
0.76
0.74
0.72
CoF at 1 N
0.7
0.68
0.66
0.64
0.62
0.6
Blood Mucin Blood Mucin
NBR NRL
Contaminant/condition
Figure 9.21. Static CoF for blood and mucin at 1N. Error bars denote standard deviation.
257
9.5.4 Synthetic blood development
The physical properties of the SBs are very similar to that of the blood, but none are an exact match.
However, the density, contact angles and viscosity are deemed close enough to be similar to that of
blood, with the exception of the gelatinous SB1. Of the 6 tested SBs, the frictional behaviour
observed was different, especially between glove materials. Friction coefficients are shown to have
little variance over the load range with the NBR material. On the other hand, the NRL materials show
greater differences with friction over the loads. This pattern in behaviour of little change over the
load range with NBR, but NRL exhibiting greater variation was also noted when using contaminants
on the various surfaces in Chapter 7. There are two major categories that the SBs can be placed in.
Those that contained particulate suspensions, and the more homogenous sugary solutions. Both of
these types of solutions appeared to exhibit very different behaviours to each other.
Particulate solutions
The difference in frictional properties and behaviour over the load range is due to both the
interaction with the materials and the individual constituents. However, when compared to the NRL,
the NBR CoF range does not vary all that greatly. For example, in SB2 where flour is present, the
friction goes from a low CoF (µ= 0.40) to a higher CoF (µ= 0.57) in the NBR, which is similar to the
NRL (µ= 0.52 at 1 N; µ= 0.68 at 5 N). The presence of flour, which is undissolved, can cause both an
increase and a decrease in friction. The friction will be low at a lower load as flour separates the two
surfaces, which allows the glove to move easily down the counter surface in a ball-bearing fashion.
On the other hand, as the force increases, the fine flour particles will fill asperities, increasing
contact area or increase the occurrence more concentrated pockets of flour particles. This is
dependent on how much of the flour is present between the glove material and the metal. This is
shown schematically in Figure 9.22.
Glove
Particles in solution
Metal
Flour particulates
Glove material “rolling”
squashed/clumping on the
metal/gloves
Figure 9.22. Behaviour of flour particulates under an increasing load.
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Due to the hydrophilic nature of the NBR, this will bring the moisture closer to the surface, and in
effect, hold some of the particulates there, causing greater separation of the metal and glove
material. This is evidenced by the lower friction observable in the powder containing SB’s with the
NBR. In the NRL however, the moisture is pushed away because of the hydrophobic nature of the
material, which could push out some of the suspended flour particles as more load is applied, hence
a greater observed friction with the NRL. The CoF also shows a decrease with the increasing load in
the NRL, which could be due to the water being pushed out and leaving more powder. Furthermore,
AFM of the NRL gloves, in Chapter 7, showed greater gaps between the bulk glove materials, and it
was hypothesised that this allows more contaminant to be pushed into the material under greater
loads, which increased the friction in the NRL over the NBR material, in some cases. This behaviour is
also observed in the SB4 solution at the lower loads, but not to as great and extent, as less flour was
present, and the solution was of a more viscous consistency than SB2.
Sugary solutions
The greatest difference in friction and blood is observed with SB3, which is composed primarily of
diluted sugar syrup, although not too viscous (compared to other sugar solutions), the result was a
sticky watery solution. Due to the simple sugary nature of the material, the CoF is shown to be the
highest in the NBR materials as more adhesion will occur. However, in the NRL, the CoF decreases
with load. As described with the flour containing solutions, this is likely to be down to the repulsion
of the SBs from the NRL surface. However, the interaction of the SBs with the NBR gloves produces
very little differences over the load range in this work. Of the SB1 diluted samples (SB6 and SB7)
there are varying behaviours between the two synthetics. In the NBR, SB6 acts very similar to SB5,
exhibiting the highest friction coefficient at the low load, possibly because the primary ingredients
are sugar and the thickening agent (methyl cellulose), which produced similar behaviour to the
sugary solution of SB5.
9.6 Synthetic blood validation

SB7, which was only a quarter of SB1 mixed with water, had the highest friction along loads 2-5 N in
the NRL gloves. However, in the NBR gloves, the CoFs produced are very similar to the blood. The
synthetic solution was so similar that there were no statistically significant differences found
between the two substances at each of the load used. This shows that a diluted mix of simple sugars
can be used in lieu of blood for friction analysis across a 1-5 N load. However, this is only pertinent
to the NBR gloves, as shown in the summary table (Table 9.9). With the NRL, none of the synthetic
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fluids matched the behaviour of the blood over the load range. However, there was a similar result
produced between the blood and the flour based liquid of SB2 at the 1 N load. Due to the
disbursement of the flour particulates when applied to the finger, it was presumed the similarity in
friction may have been a random correlation. In essence, the amount of flour and mucin contained
to the finger during the dipping procedure added is random. However, multiple repeats show
similarities to the ovine blood the 1 N target load. It was found to get this match, the solution had to
be homogenous, otherwise the friction was too high. Further work would have to be carried out with
the solutions find a solution with a similar behaviour at a higher load with the NRL. Further work
would have to be carried out with the solutions find a solution with a similar behaviour at a higher
load. However, for the purposes of industry checking how the blood has modified behaviour, looking
at the 1 N load, which is more simulative of gripping forces (189), would suffice to show the effects
of contaminants on the frictional modification of gloves.
Table 9.9. Summary of synthetic bloods which have a similar CoF to blood on each of the glove
materials along with their properties.
Glove Material NBR NRL

Synthetic Blood SB7 SB2
2.25g glucose syrup
1.25g methyl cellulose
7.85g plain flour
0.25g sodium chloride
Synthetic Blood 1g glucose anhydride
1.5 ml glycerol
Constituents 0.15g porcine gastric mucin
45 ml DI water
34 ml DI water
(Take ¼ of solution and
dilute with 40 ml of water)
PH 7.22 7.27
Density 1030.51 (±0.11) 1071.90 (±1.32)
Viscosity 2.98 (±0.01) 6.49 (±0.03)
Contact Angle 33.00 (±2.65) 135.67 (±10.26)
Static CoF at 1 N 0.75 (±0.02) 0.61 (±0.09)
Further work is also needed to explore the existence of an ideal substance which can give similar
frictional properties to blood with both glove materials. The solutions used here were adapted and
changed from one study only, which looked at viscosity (Millington paper). It is possible that, by
adjusting the constituents in solutions made in this work, a better match for the frictional properties
of both glove materials could be found. The aim of this study was to remove the requirement for
animal blood to prevent storage issues. However, porcine gastric mucin was used as a thickening
agent in the SB2 solution after finding the solution visually watery. This could draw some ethical
quandaries, as the product is from animal origins. This could be substituted with other solution-
thickening ingredients, if required. However, it could be argued that, as companies are turning more
260
towards the NBR material (38, 43), the work regarding the NBR material with SB7 is more pertinent
to the assessments required in manufacturing. This solution is solely comprised of sugary water,
using ingredients that are easy to obtain.
9.7 Conclusions
A summary of the findings of this Chapter are shown in Table 9.10, detailing the CoF differences
when gloves are contaminated, compared to dry, and surmising the SB’s which closely match the
CoFs of the different blood contaminated glove materials. SB2 and SB7 have very different
constituents, which is less than ideal, especially for industry preparation, and quick testing. Further
work is required to find a synthetic blood that works for both materials.
Table 9.10. Summary of results comparing dry gloves to blood contaminated, and the SB which
replicates the frictional properties of blood across all loads and the 1 N target force.
Glove material
Friction tests NBR NRL
Blood friction Decrease Decrease
SB match at all loads SB7 None
SB match at 1 N SB7 SB2
• Blood that possesses anti-coagulants has the same chemical interaction with NBR and NRL gloves
as fresh whole blood. In addition, spectral results show that gloves exposed to blood are
contaminated permanently, as blood has shown to bind to both the NBR and NRL materials,
causing changes to the surface chemistry. This binding is similar for both the fresh and blood and
anti-coagulated blood.
• The friction of gloves is reduced when blood is exposed to both the NRL and the NBR gloves.
However, a greater reduction in friction is observed in the NRL. It is important to note that when
the blood is applied to both materials, the friction is reduced to similar levels due to the overriding
effect of blood being present.
• The blood used in this study has a similar behaviour and frictional properties to the mucin used in
Chapter 7. Due to the presence of proteins, and conformation changes in these proteins, being
responsible for changes in viscosity when drying, it is presumed proteins affect gloves in a similar
way, regardless of the nature, and source, of the protein. This would require a greater study to
understand if this is the case. If it is found that proteins have similar reactions across different glove
261
materials. This means that one protein could be used to assess the friction modification of gloves in
industrial assessment practices.
• The work conducted in this chapter has shown a suitable match for NRL by using a combination of
sugars and flour. Although, this is only significantly similar at the 1 N load only. However, with the
NBR a match was found using a formulation of diluted sugars. This was significantly similar across
all loads used in this study. It was hoped that the development would yield a synthetic material
which matches the frictional properties of both NRL and NBR, however this is not the case. It could
be that further materials match the frictional properties of both glove materials, but this would
require further investigation.
• As the industry is aiming more focus at the NBR material, a solution had been created which
provides a suitable alternative to using blood tissues to assess frictional changes. This study has
therefore proved a suitable alternative for friction analysis for NBR without the use of animal
models, negating any storage issues, biohazardous waste disposal, or ethical concerns.
• Where this work validates synthetic models to assess blood friction, the inherent differences
in blood nature and behaviour must be considered for other studies. This work shows that
the models can be used to assess how blood modifies friction immediately after
contamination whilst still wet, but not after the blood has become tacky or dried onto the
gloves, which will occur in some cases.
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Chapter Ten: Conclusions and future work
Three areas have been explored in this thesis in order to further advance the understanding of glove
assessments and their effects on glove users. The first is the assessment of the ease of donning and
doffing different glove materials in realistic conditions (172, 173), followed by understanding how
the key chemical and physical parameters of the glove polymers affect user performance. Finally, an
understanding of the key differences between glove materials when contaminated, and how this
impacts the performance of the glove users (232). By assessing these key areas, the whole thesis has
taken the innovative approach of looking at tying together the chemistry, mechanical, and
performance parameters.
10.1 Importance of results for glove assessments

It is clear from the responses of the glove users in Chapter 3 of this thesis that gloves are perceived
to have an adverse impact on the user’s performance. The impact of these gloves still receives little-
to-no assessment at the manufacturing stage. Namely, the gloves are assessed for their main
purpose of protection and tested for their barrier properties. However pertinent the barrier integrity
is, the findings in this thesis shows that the effects gloves have on users’ performance needs to be
considered (6).
One of the most common themes noted throughout this thesis is that there is discord, in some
areas, between the published literature and industry. It would appear, through the continued
marketing of gloves aimed at improving tactility, grip, and dexterity, that the manufacturers are
aware of the common issues noted from glove users (69, 75, 95). However, it is unclear what
investigations glove manufacturers are performing to evaluate, and ultimately alleviate these issues
in-house. From the manufacturer’s perspective, understanding how the behaviour of these gloves
are modified through their daily use, and how the gloves affect user performance, will allow the
modification of properties to maximise the performance of glove users. Manufacturers do not
publish the criticisms on their products, as this allows them to improve and lead the industry with
novel technologies. However, this leaves collaboration on projects of this ilk problematic. More
transparency with the issues known by the manufacturing companies would lead to more targeted
assessments, which would lead to greater user satisfaction if perceived issues can be corrected.
Whilst it is appreciated that having an advancement in a technological area is vital for business
performance, the privacy around the technologies, and tests conducted within the industries, leaves
a vacuum in the literature, especially regarding how glove materials are assessed for their effects on
user performance (6).
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Key findings
The work conducted in this thesis has shown that the key parameters of stiffness and thickness, as
well as the way the material interacts with moisture in the skin, require critical consideration. This is
particularly important for the tribological aspects of the glove materials. The key
contributions/findings of this thesis are as follows:
• Development of methodology to assess glove donning and investigating correlations to

friction/physical properties, in both dry and wet conditions, to understand the behaviour of
gloves with different treatments. Including the manufacturing of bespoke gloves and
assessing donning performance through defined protocols. Overall, to quickly don, gloves
should be stiff, thin, and no moisture should be present.
• Development of synthetic blood surrogates that are easy to create using commercially
available constituents. These can be used in lieu of animal blood to assess the differences
in tribological properties of gloves and circumvent any safety concerns.
• Established understanding of the glove-contaminant chemical interaction, the

tribochemical effects of substances on gloves, and how this affects the performance of
glove users (dexterity and sensitivity). The hydrophobicity of the NRL shows a greater
decrease in friction, and decreased performance when contaminated. On the other hand,
the NBR gloves show little changes in friction. However, some contaminants and surfaces
lead to an increase in friction of the NBR gloves. These interactions lead to an increase in
performance when NBR gloves are contaminated with mucin. By assessing the changes
caused by contaminants, the user performance can be evaluated in more realistic
conditions, with measurable differences.
• A key outcome of this thesis shows that comparing gloves between studies, just because
they are of the same material, is imprudent. There are clear differences in the dexterity
performance of the glove users, which is linked to the polymer chemical constituents, and
in turn, their differences in mechanical properties. These mechanical properties have been
found to have correlation to their performance, especially in the case of material stiffness.
The stiffer materials were found to have lower friction coefficients, and lower
performances in dexterity.
264
The work in this thesis also revealed a gap in knowledge around the sizing of examination gloves.
The participants used throughout these studies showed to have either a finger length, or a palm
circumference measurement, larger or smaller than the recommended glove size by the Health and
Safety Executive (HSE) (149). This would imply that either the gloves are the wrong size for the users,
or that the sizing of gloves is not fit for the general population. Further research around this subject
has yielded very little, but confusing and contradictory results. Many female healthcare workers
cannot find gloves that fit their hands (229), leading to the inference that the sizes used today, are
based on archaic anthropometric data based on the hands of males (308). Thus, the HSE makes
glove size recommendations which appear to be based on outdated information, leading to
erroneous size suggestions. A more accurate sizing scale, with a wider range of glove sizes, which is
in accordance with updated anthropometric data, should be created in order to negate the issues
arising as a function of loose or tight fitting gloves which would be beneficial to improve user
performance, and in some cases, compliance (19).
A summary of the tests conducted in this thesis is shown in Table 10.1, which highlights the
principles of the protocols and tests, the outcomes from the tests, and recommendations for
improvements in the future. The tests used in this thesis could easily be implemented into glove
manufacturing plants, and into the raw material suppliers’ labs for newly developed polymers. Some
tests however require more refinement in order to save time, such as cutting down the analysis time
of the donning tests, or analysing friction at one load, rather than a range.
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Table 10.1. Summary of methodologies and assessments used in this thesis along with the key findings and recommendations for future work.
Assessment Recommendations for

Chapter Developed protocols Findings/Novelty of Research Limitations
conducted Improvement and future use
Three key stages to donning are affected by
the presence of moisture. Assessing the key
stages of donning is
Method of Doffing unaffected by material or moisture time consuming.
Donning and measuring the time presence. Addition of sweat, rather Can be
doffing of taken for gloves to
Correlations found between the glove than water could highlight circumvented by
4&5 gloves in wet be donned and
donning time and stiffness, with the thicker further differences in the assessing the time
and dry doffed and
gloves taking longer to don. donning process taken to don gloves
conditions identifying the key
as a whole, rather
stages of donning. NBR gloves treated with 1000-2000 ppm are than assessing
quicker to don, as well as polymer coated stages.
NRL.
A data bank of glove size and
Existing Discrepancies between glove sizes, glove fit to more recent
Fit of gloves to
4, 5, & 6 measurement former sizes, and general hand size, leading anthropometric data could
the hand
methods to issues with fit. further highlight
discrepancies.
NBR gloves treated with 1000-2000 ppm Protocol could be useful with
Assessment produce the least friction, as were the just one or two materials and
polymer coated NRL gloves in the wet Time consuming for
Glove-skin methodology of skin using only one specified load.
condition. multiple gloves and
friction with and material friction
4&5 conditions with
AMTI force as well as the bulk Bulk behaviour of the material changes Securing at the side of the
multiple
plate behaviour of depending on thickness. Thicker gloves plate can help assess
participants
material under load. rolled more, whilst the thinner gloves caused material behaviour under
more skin adhesion to the glove. load.
266
Repeatable and easy Using more participants with
To assess the
assessment different glove sizes to fully
Outer material friction coefficients
methodology of understand how loose/tight
friction with The stiffer the glove, the lower the friction accurately across
6 gloves with tools. fitting gloves would change
AMTI force coefficients were. multiple gloves and
Understanding of the tribology, and in turn
plate and tools. surfaces is time
material behaviour could affect
consuming.
on tool patterns. dexterity/sensitivity.
Affinity of the contaminant affects the Time taken to clean
tribological behaviour of the glove materials. More work needs to be the instrument
conducted on the effects of between
Contamination NRL shows a greater reduction in friction
blood in the various stages of contaminant use.
friction with when contaminated, and has a generally low
Friction protocol drying. Can be improved by
AMTI force surface wettability
that can aid the sticking to one
plate and tools. NBR shows a reduced friction with most of
Understanding of Further exploration of a contaminant, such
Application of
7, 8 & 9 the effects of the contaminants, however the decrease is synthetic blood which can be as blood (or the
the
different not great, and generally has a high surface used on both NRL and NBR synthetic version
contaminant to wettability.
contaminants on gloves to replicate the created in chapter
the gloves and
gloves. frictional effects of blood. 9).
monitoring of Development of a synthetic blood which can Further analysis of blood in
evaporation.
be used in place of whole blood to assess different drying stages is Different synthetic
frictional differences with gloves. required bloods needed for
each glove type.
Comparing gloves of the same material is
imprudent without chemical knowledge.
Gloves of the same core material have Will be useful for
different physical properties based on the determining effects of newer
chemical additives and physical parameters. gloves with different grip
Dexterity: Existing test
6 patterns/thicknesses when
Pegboard methods The assembly test shows greater differences,
correlated to the mechanical
thus may be more useful for assessing finer
and tribological
differences.
performance.
Correlation between performance and
stiffness as stiffer gloves restrict movement.
267
Needs to be used with a
greater variety of
contaminants with different
properties to fully Time taken to clean
understand the effects between tests is a
different contaminants may limitation,
Fine dexterity is increased due to the film
Application of mucin have. especially when
formation effects of mucin.
contaminant to multiple conditions
gloves and assessing Clear differences in glove behaviour can be Using different tests, where are studied. This
Dexterity: varied tasks and different
both dexterity and distinguished. NRL performs worse than NBR could be minimised
contaminated tools are required, could
8 sensitivity through when contaminated. by changing the
pegboard and highlight further differences
defined protocols . assessment to
CSPDT Reduction in friction with the NRL adversely between materials and the
Novel to assessing assess
affects the gross dexterity and sensitivity of effects of different
dexterity with contamination on
NRL glove users. contaminants. Assessments
medical gloves. the equipment in
that require greater the first instance,
interaction with the rather than the
environment would be more gloves.
simulative of tasks
conducted when gloves are
worn.
Requires a wider
NRL provides greater sensitivity than the Re-print test bed to remove bumps range, also
Protocol developed NBR glove. defects on board. some other
to apply discrimination on
Sensitivity: NBR shows improved sensitivity when Conduct with a greater
contaminants and the test (such as
contaminated contaminated. variety of contaminants.
repeatable purposely
8 simulated measures of NRL shows a decrease in sensitivity when Further tests could be manufactured
medical tactile sensitivity. Novel to contaminated. developed to measure the grooves) to help
test (bumps) assessing sensitivity
Useful method for determination of impact of contaminants, such with differentiating
with medical gloves. dampened sensitivity from placing gloves as measuring vibration differences
over the fingers. transmission. between gloves and
conditions.
268
10.2 Effects of glove properties
A summary of the gloves’ properties, and their effects on the user/performance are shown in Figure
10.1. The figure highlights the effects of each of the properties analysed in this thesis if the property
is increased. For example, in the case of the wettability of the glove materials, an increase in the
surface wettability property leads to an increase in friction and chemical interaction over the less
wettable surface. The increase in both of these behaviours, leads to an increase in dexterity and
sensitivity. The positive icons indicate an increase, whilst the negative indicates a decrease. In each
case, these can be reversed to obtain an opposite effect.
Caveats do exist however, for example as the size decreases, this still has a negative effect
on the glove fit, as it will be too small, which will incur restricted movement and greater effects on
dexterity. Ideally, a glove should be of a low stiffness, with a good surface wettability with a good fit.
This produces gloves which are easy to don and increases dexterity and sensitivity performance of
users when compared other gloves. Of the parameters addressed, the most affected is the dexterity
of the glove users. By changing the material properties studied in this thesis, at the manufacturing
stage, improvements could be made on the performance of the gloves, as noted in the donning in
Chapter 5 where different thicknesses and chemical treatment strengths were analysed. In some
cases, the material parameters are intrinsically affected by one another, such as the material
thickness having an effect on the stiffness. Therefore, adjusting the thickness will impact the
stiffness of the gloves, which will, in turn, affect the dexterity and ease of glove donning.
269
Figure 10.1. Properties assessed in the thesis and how they link to the effects on the gloves and the user performance as the property increases (e.g.
thickness gets thicker). ‘+’ indicates an increase, whilst ‘-‘ indicates a decrease.
270
10.3 Recommendations to industry
• The work conducted in this thesis shows that there is a correlation between the stiffness of the
gloves and the performance parameters (such as dexterity and donning) as well as between
tensile strength and performance. It is possible that the correlation between tensile strength
and the performance is not a causation, but an indirect correlation as correlations were found
between the stiffness and the tensile strength. Further research would need to be carried out
to assess this correlation, but the research presents interesting findings, nonetheless. The work
conducted suggests that by paying closer attention to these parameters, the performance could
be predicted. Stiffer materials were shown to induce a poorer user performance, but reduced
friction as the stiffer material is less likely to locally deform.
• For the examination gloves being sold, there are statements of ‘increased friction’ or ‘increased
grip’, but no information around the effect of contamination of these gloves, or even the tests
used to assess the friction, can be ascertained. The work in this thesis has shown that the
frictional properties of gloves are modified upon exposure to both powder and liquid
contamination. Assessing these contaminant tribological interactions with newer NBR grade
gloves will greatly inform of the differences in contaminant interaction, and tribological
changes, which are salient to the performance. The use of the synthetic blood developed in
Chapter 9 of this thesis would be useful in aiding this understanding.
• Assessing frictional properties in-house when different glove formulations are developed is vital
for moving the industry forward. Tribological differences are present between different grades
of nitrile materials, which could cause issues with dropping equipment, and more fatigue
overtime, as more force is exerted to grip equipment. This is especially pertinent in covid-19
outbreaks, in which glove use is becoming more and more frequent, and gloves are worn for
tasks which they were previously not worn before.
• When developing gloves with novel polymer coatings, assessing the time taken to don the
gloves, in conjunction with the friction measurements would be beneficial, and may show
greater differences. In addition, when chlorinating gloves, chlorinating to around 1000ppm
appears to be more beneficial to NBR materials. However, when the hands have some moisture
present, chlorinating to 2000 ppm shows to be more advantageous. It is possible that an
optimum chlorination strength exists in between these two strengths, however the frictional
properties should not be the only consideration in the process. The material stiffness, as
suggested, plays an important part in the way the gloves move around the fingers, as well as
stretch around the hand to ensure an easier donning.
271
• One of the common comments obtained from the questionnaire in the third Chapter of this
thesis was around the fit of gloves. There is a requirement for manufacturers to assess how the
sizing grades may affect the donning performance, as it would appear the sizing is based on
outdated information and does not apply to the majority of the population. Newer, or even
reviewed, sizing could alleviate some of the issues glove users have, as better fitting gloves
could remove dexterity and sensitivity issues which users often encounter.
10.4 Future work

The work presented in this thesis brings up some interesting correlations between the physical
parameters and the performance of dexterity and donning. Further analysis of these parameters
with a larger sample size will provide further confidence in these results. Some of the test
procedures, such as the donning methodology created, could be repeated using sweat, rather than
just water in order to assess the differences in frictional interactions. Additionally, as the covid-19
pandemic is very much prevalent, and regular hand-washing is encouraged, a larger range of skin
care products are likely to be present on hands prior to donning gloves (178). These products are
namely moisturisers used due to frequent hand washing, which will provide more moisture to the
skin. As well as an increase in moisturisers, hand cleaning products are also more frequently used.
Under current guidelines, these are 70% (minimum) alcohol based hand sanitisers (309), which will
dry the skin out, reducing the moisture to abnormal levels. Assessing how these materials and
coatings interact with these products would further advance the knowledge of how the different
coatings affect donning and doffing in different hand conditions.
As covid-19 forces industries to use more PPE, particularly gloves, there is a likelihood more
issues will arise as a result of an increase of both more frequent use, and more frequent users (30).
This does not pertain solely to the medical field. As stated in the introduction to this thesis, medical
gloves are worn in a myriad of fields, and are used for many more applications. Gloves will now be
worn for situations where they were not required previously, highlighting further issues.
Ascertaining greater information regarding how gloves may affect performance in other fields will
increase the knowledge of how to incorporate more standard tests, more contaminants that gloves
are exposed to, and understand the material parameters which may affect the performance in
different areas. Therefore, it would be interesting to carry out another study based on the views of
glove users to widen the particular issues of interest.
A few caveats exist in the studies conducted in the thesis, such as the correlation of
parameters to the strain once the glove is on the hand. Measuring strain when the glove is on the
272
hand has not been previously carried out. Using instrumentation such as digital image correlation
would advance the knowledge in this area. Knowing the strain that a glove undergoes and assessing
how that strain affects dexterity and sensitivity, could be vital for performance measuring. This ties
in very closely for the requirement to assess the general sizing of medical examination gloves.
One of the issues highlighted by glove manufacturers was with getting polymer coatings to
bind to the NBR material. This knowledge is missed in the literature but is known by the glove
manufacturers, which would explain some of the differences in results between studies assessing
these coatings. Studies oriented at these technologies will allow greater understanding of what is
happening at the skin-glove material interface, allowing insight for further technological
advancements to help with glove donning.
Many of the contaminants used in this thesis are of both a polar and non-polar nature,
meaning their interactions will be difference based upon exposure to different glove materials.
However, the interaction, although based on a lot of information regarding the chemistry of the
materials and contaminants, does need further work for confirmation of key interactions. Knowing
what the gloves are composed of, in full, is key to understanding this. X-ray diffraction is a useful tool
for targeted analysis of what may be present on the surface of the glove materials, which will allow
for greater understanding of the surface chemistry. By understanding this on a molecular level, the
interaction with the contaminants can then be understood, and the surface chemistry could be
modified to increase or decrease the tribological interactions with different surfaces. Additionally,
more analytical chemistry techniques could be used to assess how contaminants are affecting gloves
on a chemical level, such as mass spectrometry to assess if contaminants are present on the gloves
through simple adhesion, or if there are chemical interactions.
Tying together the physical and chemical interactions gloves have with their environment is
paramount to identifying how gloves are affecting both user perception and performance. Only by
assessing the gloves in the conditions they are used in can the effects of gloves be identified. Future
tests should be considering the impacts gloves have on users once they are contaminated, rather
than just assessing in dry, unrealistic conditions. Ultimately, by making the tests more representative
of the environments gloves are used in, this thesis shows that sensitivity, dexterity, friction, and the
donning efficiency of gloves are affected by contamination (172, 173, 232). It is hoped that the
methodology developed and implemented in this thesis, along with the advancement in knowledge
of the chemical interactions and friction differences, can lead the industry to a better understanding
of how medical examination gloves affect user performance.
273
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Appendices
Appendix A – Publications
Publications
• PREECE, D, LEWIS, R and CARRÉ, MJ. Efficiency of Donning and Doffing Medical Examination
Gloves. International Journal of Ergonomics [online]. 2020. Vol. 10, no. 1, p. 1–17.
• PREECE, D, LEWIS, R and CARRÉ, MJ. A critical review of the assessment of medical gloves.
Tribology - Materials, Surfaces & Interfaces [online]. 2020. P. 1–10. DOI
10.1080/17515831.2020.1730619.
• PREECE, D, LEWIS, R and CARRÉ, MJ. Effects of Mucin on the dexterity and tactile sensitivity
of medical glove users. Biotribology [online]. 2020. Vol. 24, 100146. DOI
10.1016/j.biotri.2020.100146.
• PREECE, D, HONG, T, TONG, HK, LEWIS, R and CARRÉ, MJ. The effects of chlorination,
thickness, and moisture on glove donning efficiency. Ergonomics [online]. 2021. P. 1-12 DOI
10.1080/00140139.2021.1907452.
WATSON, M, CHRISTOFOROU, P, HERRERA, P, PREECE, D, CARRELL, J, HARMON, M, KRIER, P,

LEWIS, S, MAITI, R, SKIPPER, W, TAYLOR, E, WALSH, J, ZALZALAH, M, ALHADEFF, L, KEMPKA,
R, LANIGAN, J, LEE, ZS, WHITE, B, ISHIZAKA, K, LEWIS, R, SLATTER, T, DWYER-JOYCE, R and
MARSHALL, M. An analysis of the quality of experimental design and reliability of results in
tribology research. Wear [online]. April 2019. Vol. 426–427, p. 1712–1718. DOI
10.1016/j.wear.2018.12.028.
Conferences
• PREECE, D, LEWIS, R and CARRÉ, MJ. A review of the assessment of medical gloves.
Poster presented at: Tribomotion: Where performance and motion meet friction. 44th
Leeds Lyon Symposium on Tribology. 4th-6th September 2017; Lyon, France.
• PREECE, D, LEWIS, R and CARRÉ, MJ. A review of the assessment of medical gloves.
Poster presented at: Tribology in motion. TriboUK 2017. 27th-28th April 2017; London,
UK.
• PREECE, D, LEWIS, R and CARRÉ, MJ. The Effects of Mucin on Medical Glove Users and
Dexterity and Tactile Sensitivity. Poster presented at: The Impact of Tribology in the
Modern World. TriboUK 2018. 12th-13th April 2018; Sheffield, UK.
• PREECE, D, LEWIS, R and CARRÉ, MJ. Effects of mucin on medical glove tribology and
performance. Oral presentation at: Tribology in daily life. 46th Leeds Lyon Symposium on
Tribology. 4th-6th September 2019; Lyon, France.
296
Appendix B – Supplementary data for Chapter Four
B1. Total donning times for each step with paired t-test results for total time taken between dry and
wet conditions (n=14).
Average times taken for each step (s)

Hand Total
Glove/Condition Preparation Manipulation t-test
Insertion donning time
1.21 1.95 0.83 3.99
Dry
Cl (±0.71) (±0.93) (±0.54) (±1.18) t(13)=-3.183
NBR 1.48 3.88 1.14 6.50 p=.007*
Wet
(±0.99) (±.2.13) (±0.98) (±3.34)
1.53 2.33 0.97 4.83
Dry
PC (±1.43) (±1.06) (±0.77) (±2.74) t(13)=-2.901
NBR 1.67 4.84 1.08 7.59 p=.012*
Wet
(±0.85) (±3.10) (±0.63) (±4.35)
1.14 1.94 1.2 4.28
Dry
Cl (±0.71) (±0.91) (±0.92) (±1.47) t(13)=-3.125
NRL 1.21 4.63 1.07 6.91 p=.008*
Wet
(±0.63) (±3.24) (±0.98) (±4.13)
0.95 2.13 0.92 4.00
Dry
PC (±0.54) (±1.07) (±0.75) (±1.71) t(13)=-1.646
NRL 0.99 3.06 0.78 4.83 p=.124
Wet
(±0.63) (±1.47) (±0.51) (±1.70)
± denotes standard deviation, * Indicates statistical significance (p<.05)
B2. Time taken for participants to doff gloves, with paired t-tests comparing dry and wet conditions.
Glove/Condition Time taken (s) t-test

Dry 1.68 (±0.45) t(13)=-0.587
Cl NBR
Wet 1.80 (±0.80) p=.562
Dry 1.93 (±0.29) t(13)=-0.090
PC NBR
Wet 1.84 (±0.65) p=.407
Dry 1.80 (±0.41) t(13)=-0.089
Cl NRL
Wet 1.80 (±0.46) p=.928
Dry 1.63 (±0.55) t(13)=-0.765
PC NRL
Wet 1.78 (±0.42) p=.452
± denotes standard deviation.
297
B3. Friction coefficients for each participant in each condition
Chlorinated NBR
Participant
1 2 3 4
Condition Load (N) µ Load (N) µ Load (N) µ Load (N) µ
0.09 3.04 0.10 3.63 0.10 3.79 0.10 3.55
0.22 2.55 0.23 2.60 0.21 2.52 0.24 2.16
Dry 0.57 1.27 0.57 1.73 0.50 1.55 0.33 2.28
0.71 1.49 0.80 1.74 0.83 1.56 0.77 1.85
1.04 1.10 0.98 1.68 1.03 1.19 1.04 1.44
0.14 2.26 0.17 4.09 0.11 4.42 0.15 4.80
0.30 1.85 0.39 2.17 0.26 2.96 0.30 2.67
Wet 0.39 1.70 0.42 2.20 0.35 2.47 0.44 2.35
0.80 1.28 0.87 1.32 0.84 1.33 0.85 1.87
1.13 1.39 0.93 1.87 1.04 1.52 1.03 1.62
Polymer Coated NBR
Participant
1 2 3 4
0.11 2.73 0.12 4.51 0.11 3.71 0.13 3.52
0.36 1.93 0.3 2.05 0.28 2.85 0.32 1.97
Dry 0.41 1.72 0.4 2.18 0.33 2.74 0.39 2.11
0.82 1.58 0.77 2.15 0.70 1.57 0.79 1.73
0.95 1.01 0.94 2.06 0.94 1.67 1.04 1.57
0.10 5.17 0.12 6.73 0.10 6.50 0.09 8.81
0.29 3.50 0.29 3.67 0.28 4.38 0.23 5.60
Wet 0.37 3.00 0.36 3.18 0.34 3.95 0.34 4.22
0.76 2.03 0.79 2.62 0.63 2.27 0.78 1.76
1.08 1.68 1.01 1.88 1.02 1.47 1.09 1.69
Chlorinated NRL
Participant
1 2 3 4
0.12 1.93 0.11 3.44 0.13 2.65 0.11 5.39
0.30 1.34 0.20 3.36 0.25 2.75 0.27 1.66
Dry 0.48 1.20 0.39 2.19 0.43 2.07 0.37 1.15
0.79 1.08 0.89 1.93 0.79 2.08 0.76 1.29
1.04 1.11 0.90 1.65 1.06 1.52 0.88 1.39
0.10 1.99 0.08 4.86 0.11 4.27 0.10 4.86
0.28 2.07 0.35 2.19 0.27 4.78 0.38 2.23
Wet 0.38 1.86 0.51 2.52 0.48 3.44 0.48 2.18
0.80 1.56 0.73 2.20 0.80 2.12 0.72 2.31
1.05 1.49 0.89 2.11 1.03 2.21 1.09 2.26
298
Polymer Coated NRL
Participant
1 2 3 4
0.10 1.18 0.09 2.66 0.12 1.26 0.13 1.21
0.25 1.32 0.22 1.86 0.21 2.25 0.25 1.82
Dry 0.44 1.26 0.42 1.67 0.39 1.85 0.45 1.79
0.74 1.24 0.74 2.00 0.78 1.61 0.73 1.81
1.03 1.03 0.96 1.54 1.02 1.48 0.96 1.61
0.13 1.71 0.09 2.81 0.11 2.29 0.12 2.64
0.28 2.05 0.28 2.19 0.31 1.78 0.29 1.99
Wet 0.34 2.05 0.44 1.80 0.37 1.75 0.34 1.48
0.81 1.83 0.72 1.83 0.8 1.40 0.73 1.54
1.04 1.9 0.89 1.90 1.02 1.56 0.99 1.84
B4. Paired t-tests of friction between wet and dry conditions of NBR gloves
Participant
Condition Load 1 2 3 4
t(2)=8.437 t(2)=6.867 t(2)=4.706 t(2)=5.243
0.1
p=.047* p=.037* p=.032* p=.014*
t(2)=0.990 t(2)=1.520 t(2)=2.452 t(2)=10.267
0.25
p=.124 p=.523 p=.138 p=.659
Polymer t(2)=0.273 t(2)=-5.620 t(2)=1.606 t(2)=1.797
0.5
coated p=.158 p=.034* p=.514 p=.648
t(2)=4.634 t(2)=1.175 t(2)=2.645 t(2)=0.407
0.75
p=.478 p=.134 p=.184 p=.325
t(2)-3.077 t(2)=-0.678 t(2)=-1.372 t(2)=0.725
1
p=.156 p=.189 p=.844 p=.072
t(2)=2.051 t(2)=-1.681 t(2)=-8.630 t(2)=-7.278
0.1
p=.103 p=.960 p=.020* p=.014*
t(2)=3.942 t(2)=-1.633 t(2)=-4.301 t(2)=-0.644
0.25
p=.272 p=.008* p=.006* p=.238
t(2)=-5.399 t(2)=-1.300 t(2)=-5.008 t(2)=0.930
Chlorinated 0.5
p=.001* p=.695 p=.313 p=.164
t(2)=-4.704 t(2)=1.899 t(2)=2.740 t(2)=-0.046
0.75
p=.065 p=.641 p=.028* p=.183
t(2)=-2.133 t(2)=-2.133 t(2)=-2.119 t(2)=-1.284
1
p=.046* p=.295 p=.053 p=.218
*Denotes statistical significance (p<.05)
299
B5. Paired t-tests of friction between wet and dry conditions of NRL gloves
Participant
Condition Load 1 2 3 4
t(2)=-1.856 t(2)=-2.78 t(2)= -2.794 t(2)=4.117
0.1
p=.241 p=.007 p=.157 p=.016*
t(2)=-2.283 t(2)=-1.418 t(2)=-0.523 t(2)=-0.198
0.25
p=.144 p=.342 p=.634 p=.847
Polymer t(2)=-3.373 t(2)=0.474 t(2)=3.559 t(2)=1.327
0.5
coated p=.165 p=.720 p=.890 p=.323
t(2)= 1.319 t(2)=-0.455 t(2)=0.778 t(2)=0.763
0.75
p=.436 p=.536 p=.404 p=.524
t(2)= -3.526 t(2)=-1.065 t(2)=-0.682 t(2)=-0.992
1
p=.128 p=.352 p=.623 p=.440
t(2)=1.445 t(2)=3.443 t(2)=-10.030 t(2)=-1.227
0.1
p=.080 p=.121 p=.002* p=.252
t(2)=16.978 t(2)=-3.383 t(2)=-2.594 t(2)=-0.442
0.25
p=.005* p=.067 p=.206 p=.777
t(2)= 14.599 t(2)=1.278 t(2)=0.0569 t(2)=4.515
Chlorinated 0.5
p=.054 p=.109 p=.250 p=.049
t(2)=13.631 t(2)= 1.460 t(2)=-0.96 t(2)=7.695
0.75
p=.002* p=.198 p=.808 p=.023*
t(2)=23.100 t(2)=44.530 t(2)=-4.343 t(2)=4.762
1
p=.014* p=<.001* p=.081 p=.036*
*Denotes statistical significance (p<.05)
300
Appendix C – Supplementary data for Chapter Five
C1. Statistics for differences in donning time regarding thickness (Section 5.4.5)
C1.1. One-Way ANOVA analysis of the donning time of a single glove in dry and wet conditions.
p-value
Condition
Thin Thick
F(3, 44)=2.464 F(3, 44)= 2.329
Dry
p=.075 p=.087
F(3, 44)=1.754 F(3, 44)=2.845
Wet
p=.170 p=.048*
C1.2. Tukey HSD analysis donning time of the thick gloves in wet condition (ANOVA =F(3, 44)=2.845
p=.048).
Pair Q-stat p-value

E vs F 1.996 .500
E vs G 0.859 .900
E vs H 3.902 .040*
F vs G 1.137 .835
F vs H 1.906 .534
G vs H 3.043 .153
C1.3. Kruskal-Wallis of thin and thick gloves in dry and wet conditions from the preparation stage of
donning.
Results
Condition
Thin Thick
H(3, 44)=1.325 H(3, 44)=1.200
Dry
p=.222 p=.753
H(3, 44)=0.876 H(3, 44)=4.260
Wet
p=.831 p=.235
C1.4. Kruskal-Wallis of thin and thick gloves in dry and wet conditions from the hand insertion stage
of donning.
Results
Condition
Thin Thick
H(3, 44)=3.650 H(3, 44)=2.641
Dry
p=.302 p=.133
H(3, 44)=2.746 H(3, 44)=8.736
Wet
p=.433 p=.019*
301
C1.5. Kruskal-Wallis of thin and thick gloves in dry and wet conditions from the manipulation of
donning.
Results
Condition
Thin Thick
H(3, 44)=1.486 H(3, 44)=2.852
Dry
p=.686 p=.415
H(3, 44)=2.328 H(3, 44)=0.723
Wet
p=.507 p=.868
C1.6. P-values of Post-Hoc Dunn test of thick gloves in the wet condition from the hand insertion
stage of donning.
Glove p-value
sample E F G
Z=1.506
F
p=.066
Z=-0.619 Z=0.085
G
p=.268 p=.466
Z=2.878 Z=0.769 Z=1.635
H
p=.002* p=.221 p=.051
C1.7. t-test results comparing thin and thick gloves in dry and wet conditions.
Results
Glove Sample
Dry Wet
t(11)=-1.140 t(11)=-1.842
500ppm
p=.115 p=.630
t(11)=-2.823 t(11)=-1.440
1000ppm
p=.008* p=.828
t(11)=-0.698 t(11)=-0.848
1500ppm
p=.503 p=.252
t(11)=0.116 t(11)=-0.904
Control
p=.897 p=.350
302
C2. Friction coefficients for participants 1-3
C2.1. CoF of wet and dry for participant 1
Load (N)
Glove Sample Condition
Low Medium High
Dry 2.80 (±0.05) 1.89 (±0.01) 1.98 (±0.01)
A
Wet 5.44 (±0.27) 2.17 (±0.02) 1.98 (±0.01)
Dry 1.58 (±0.04) 2.56 (±0.02) 2.09 (±0.04)
B
Wet 1.88 (±0.03) 2.11 (±0.02) 1.82 (±0.05)
Dry 2.49 (±0.07) 2.64 (±0.01) 2.44 (±0.01)
C
Wet 3.39 (±0.01) 1.96 (±0.05) 1.84 (±0.01)
Dry 5.65 (±0.17) 3.07 (±0.03) 2.69 (±0.01)
D
Wet 6.78 (±0.01) 3.75 (±0.21) 1.99 (±0.03)
Dry 2.66 (±0.01) 2.18 (±0.04) 1.95 (±0.01)
E
Wet 6.40 (±0.24) 2.68 (±0.04) 2.98 (±0.03)
Dry 2.80 (±0.05) 2.15 (±0.01) 1.89 (±0.01)
F
Wet 3.15 (±0.01) 2.85 (±0.01) 2.65 (±0.01)
Dry 2.02 (±0.07) 1.52 (±0.01) 1.38 (±0.01)
G
Wet 6.81 (±0.43) 2.77 (±0.04) 1.82 (±0.03)
Dry 2.11 (±0.06) 1.82 (±0.01) 1.67 (±0.01)
H
Wet 1.40 (±0.32) 2.45 (±0.03) 1.79 (±0.03)
Load (N)
Low Medium High
Dry 5.06 (±0.19) 2.66 (±0.04) 2.17 (±0.03)
A
Wet 6.55 (±0.71) 2.62 (±0.01) 2.76 (±0.02)
Dry 2.36 (±0.07) 1.83 (±0.01) 1.63 (±0.02)
B
Wet 2.64 (±0.01) 2.10 (±0.01) 2.07 (±0.01)
Dry 3.32 (±0.14) 2.14 (±0.08) 1.91 (±0.01)
C
Wet 4.88 (±0.05) 3.37 (±0.04) 3.08 (±0.02)
Dry 4.78 (±0.06) 3.94 (±0.02) 4.44 (±0.07)
D
Wet 5.63 (±0.33) 3.63 (±0.04) 3.16 (±0.02)
Dry 7.33 (±0.40) 3.19 (±0.18) 2.13 (±0.06)
E
Wet 10.43 (±0.40) 3.70 (±0.12) 2.55 (±0.04)
Dry 3.43 (±0.07) 2.17 (±0.01) 1.78 (±0.02)
F
Wet 4.77 (±1.13) 2.44 (±0.08) 3.38 (±0.03)
Dry 4.84 (±0.29) 1.87 (±0.06) 1.34 (±0.06)
G
Wet 10.76 (±1.18) 3.48 (±0.10) 2.34 (±0.13)
Dry 2.96 (±0.02) 2.17 (±0.03) 1.91 (±0.01)
H
Wet 2.81 (±0.02) 2.56 (±0.01) 2.41 (±0.04)
303
Load (N)
Low Medium High
Dry 3.18 (±0.21) 1.33 (±0.01) 1.68 (±0.02)
A
Wet 3.06 (±0.06) 2.23 (±0.02) 2.08 (±0.01)
Dry 1.85 (±0.22) 1.97 (±0.01) 1.58 (±0.01)
B
Wet 3.58 (±0.27) 2.89 (±0.02) 1.85 (±0.01)
Dry 1.12 (±0.22) 0.46 (±0.01) 1.29 (±0.17)
C
Wet 3.15 (±0.13) 2.88 (±0.03) 2.34 (±0.01)
Dry 3.76 (±0.23) 0.93 (±0.03) 0.62 (±0.06)
D
Wet 4.15 (±0.17) 2.19 (±0.12) 1.58 (±0.03)
Dry 2.93 (±0.02) 2.45 (±0.19) 1.91 (±0.08)
E
Wet 5.16 (±0.13) 2.34 (±0.01) 2.29 (±0.01)
Dry 4.78 (±0.08) 2.22 (±0.04) 1.40 (±0.03)
F
Wet 4.02 (±0.01) 2.03 (±0.02) 2.14 (±0.11)
Dry 3.44 (±0.88) 0.93 (±0.01) 1.35 (±0.13)
G
Wet 4.61 (±0.10) 3.36 (±0.05) 2.28 (±0.12)
Dry 1.22 (±0.01) 1.62 (±0.05) 2.08 (±0.02)
H
Wet 1.29 (±0.35) 2.91 (±0.01) 2.40 (±0.17)
304
C3. Data and statistical tests for friction regarding participant 1 (Section 5.4.6)
C3.1. ANOVA tests conducted on friction results from Participant 1 investigating for differences in
results across all conditions
Thin Thick
Load Dry Wet Dry Wet
F(3,8)=976.320 F(3,8)=756.732 F(3,8)=176.097 F(3,8)=241.911
Low
p=<.001* p=<.001* p=<.001* p=<.001*
F(3,8)=2482.993 F(3,8)=174.823 F(3,8)=530.352 F(3,8)=88.559
Medium
p=<.001* p=<.001* p=<.001* p=<.001*
F(3,8)=595.879 F(3,8)=30.076 F(3,8)=379.920 F(3,8)=1551.714
High
p=<.001* p=<.001* p=<.001* p=<.001*
* Denotes statistical signifnicance (p<.05)
305
C3.2. Tukey’s HSD test conducted on thin and thick gloves in dry and wet conditions from Participant
1.
Dynamic Dry Dynamic Wet

Load Glove
A B C A B C
(N) Sample
Q= 21.711 Q= 45.155
B
p=.001* p=.001*
Q=5.492 Q=16.219 Q=25.959 Q=19.196
0.1 C
p=.020* p=.001* p=.001* p=.001*
Q=50.641 Q= 72.352 Q= 53.133 Q=17.007 Q=62.162 Q=42.966
D
p=.001* p=.001* p=.001* p=.001* p=.001* p=.001*
Q=68.380 Q=0.936
B
p=.001* p=.900
Q= 76.908 Q=8.528 Q=3.362 Q=2.426
0.5 C
p=.001* p=.001* p=.159 p=.377
Q=120.490 Q=52.110 Q=43.582 Q=24.859 Q=25.796 Q=28.221
D
p=.001* p=.001* p=.001* p=.001* p=.001* p=.001*
Q=7.670 Q=9.661
B
p=.003* p=.001*
Q=34.373 Q=26.703 Q=8.689 Q=0.972
1 C
p=.001* p=.001* p=.001* p=.896
Q=25.942 Q= 45.272 Q=18.569 Q=0.580 Q=10.241 Q=9.269
D
p=.001* p=.001* p=.001* p=.900 p=.001* p=.001*
Load Glove
E F G E F G
(N) Sample
Q=4.791 Q=19.395
F
p=.039* p=.001*
Q=21.715 Q=26.505 Q=2.424 Q=21.818
0.1 G
p=.001* p=.001* p=.378 p=.001*
Q=18.771 Q=23.562 Q=2.944 Q=29.871 Q=10.476 Q=32.294
H
p=.001* p=.001* p=.238 p=.001* p=.001* p=.001*
Q=34.088 Q=8.836
F
p=.001* p=.001*
Q=30.275 Q=3.812 Q=4.771 Q=4.065
0.5 G
p=.001* p=.102 p=.039* p=.080
Q=13.752 Q=20.336 Q=16.523 Q=12.845 Q=21.68 Q=17.616
H
p=.001* p=.001* p=.001* p=.001* p=.001* p=.001*
Q=21.651 Q=21.651
F
p=.001* p=.001*
Q=76.115 Q=54.464 Q=76.115 Q=54.464
1 G
p=.001* p=.001* p=.001* p=.001*
Q=78.472 Q=56.821 Q=2.357 Q=78.472 Q=56.821 Q=2.357
H
p=.001* p=.001* p=.399 p=.001* p=.001* p=.400
306
C3.3. T-tests conducted on participant 1 assessing differences in friction between the thin and thick
gloves chlorinated to the same concentration.
Dynamic
Load
Dry Wet
t(2)=-4.457 t(2)=-3.536
Low
p=.047* p=.072
t(2)=11.764 t(2)=-39.991
A-E Medium
p=.007* p=.879
t(2)=-5.741 t(2)=9.274
High
p=.029* p=.033*
t(2)=24.497 t(2)=57.704
Low
p=.002* p=<.001*
t(2)=-73.674 t(2)=41.284
B-F Medium
p=<.001* p=.224
t(2)=7.143 t(2)=25.335
High
p=.019* p=.002*
t(2)=-5.932 t(2)=13.554
Low
p=.027* p=.005*
t(2)=-296.052 t(2)=-28.273
C-G Medium
p=<.001* p=.002*
t(2)=-157.469 t(2)=0.760
High
p=<.001* p=.527
t(2)=-28.301 t(2)=-29.714
Low
p=.001* p=.001*
t(2)=-13.996 t(2)=11.157
D-H Medium
p=.005* p=.008*
t(2)=29.425 t(2)=5.676
High
p=.001* p=.030*
307
C3.4. T-tests conducted on participant 1 assessing differences in friction between the dry and wet
conditions.
Dynamic
Glove Sample Low Load Mid Load High load
t(2)=18.993 t(2)=20.669 t(2)=-7.777
A
p=.003* p=.002* p=.016*
t(2)=51.525 t(2)=-18.514 t(2)=-17.843
B
p=<.001* p=.003* p=.003*
t(2)=27.000 t(2)=-27.712 t(2)=-117.081
C
p=.001* p=.001* p=<.001*
t(2)=11.484 t(2)=5.643 t(2)=-34.865
D
p=.007* p=.030* p=.001*
t(2)=27.912 t(2)=16.842 t(2)=46.854
E
p=.007* p=.003* p=.001*
t(2)=15.067 t(2)=113.934 t(2)=153.871
F
p=.004* p=.004* p=<.001*
t(2)=23.361 t(2)=47.888 t(2)=24.634
G
p=.004* p=<.001* p=.002*
t(2)=-4.724 t(2)=39.733 t(2)=7.098
H
p=.042* p=<.001* p=.019*
308
Thin Thick
F(3,8)=41.645 F(3,8)=64.916 F(3,8)=183.069 F(3,8)=68.383
Low
p=<.001* p=<.001* p=<.001* p=<.001*
F(3,8)=1229.862 F(3,8)=2008.825 F(3,8)=112.884 F(3,8)=156.675
Medium
p=<.001* p=<.001* p=<.001* p=<.001*
F(3,8)=3418.990 F(3,8)=2462.809 F(3,8)=176.040 F(3,8)=137.126
High
p=<.001* p=<.001* p=<.001* p=<.001*
309
2.
Dry Wet
Load Glove
A B C A B C
(N) Sample
Q=13.735 Q=18.79
B
p=.001* p=.001*
Q=8.854 Q=4.882 Q=8.090 Q=10.789
0.1 C
p=.001* p=.035* p=.002* p=.001*
Q=1.422 Q=12.313 Q=7.432 Q=4.468 Q=14.411 Q=3.622
D
p=.733 p=.001* p=.003* p=.053 p=.001* p=.124
Q=32.264 Q=33.169
B
p=.001* p=.001*
Q=20.189 Q=12.076 Q=48.154 Q=81.323
0.5 C
p=.001* p=.001* p=.001* p=.001*
Q=49.530 Q=81.794 Q=69.718 Q=64.798 Q=97.697 Q=16.644
D
p=.001* p=.001* p=.001* p=.001* p=.001* p=.001*
Q=24.738 Q=69.602
B
p=.001* p=.001*
Q=11.765 Q=12.973 Q=31.124 Q=100.730
1 C
p=.001* p=.001* p=.001* p=.001*
Q=103.021 Q=127.760 Q=114.78 Q=39.695 Q=109.300 Q=8.571
D
p=.001* p=.001* p=.001* p=.001* p=.001* p=.001*
Load Glove
E F G E F G
(N) Sample
Q=26.883 Q=11.678
F
p=.001* p=.001*
Q=17.141 Q=9.742 Q=0.670 Q=12.349
0.1 G
p=.001* p=.001* p=.900 p=.001*
Q=30.112 Q=3.229 Q=12.972 Q=15.709 Q=4.031 Q=16.379
H
p=.001* p=.181 p=.001* p=.001* p=.082 p=.001*
Q=18.685 Q=24.803
F
p=.001* p=.001*
Q=24.308 Q=5.632 Q=4.411 Q=20.391
0.5 G
p=.001* p=.017* p=.056 p=.080
Q=18.770 Q=0.085 Q=5.539 Q=22.381 Q=2.422 Q=19.969
H
p=.001* p=.900 p=.019* p=.001* p=.378 p=.001*
Q=13.736 Q=20.289
F
p=.001* p=.001*
1
Q=31.495 Q=17.759 Q=4.915 Q=25.204
G
p=.001* p=.001* p=.034* p=.001*
310
Q=8.808 Q=4.927 Q=22.686 Q=3.390 Q=23.679 Q=1.521
H
p=.001* p=.034* p=.001* p=.155 p=.001* p=.696
Dynamic
Load
Dry Wet
t(2)=6.782 t(2)=15.110
Low
p=.021* p=.004*
t(2)=-5.799 t(2)=-14.241
A-E Medium
p=.029* p=.005*
t(2)=1.897 t(2)=-21.918
High
p=.198 p=.002*
t(2)=13.407 t(2)=-3.297
Low
p=.006* p=.081
t(2)=148.035 t(2)=-7.755
B-F Medium
p=<.001* p=.016*
t(2)=-39.222 t(2)=86.392
High
p=<.001* p=<.001*
t(2)=6.175 t(2)=9.010
Low
p=.025* p=.012*
t(2)=7.674 t(2)=-3.132
C-G Medium
p=.017* p=.089
t(2)=-16.351 t(2)=-9.568
High
p=.004* p=.011*
t(2)=-4.842 t(2)=-102.853
Low
p=.040* p=<.001*
t(2)=-55.720 t(2)=49.795
D-H Medium
p=<.001* p=.001*
t(2)=-73.001 t(2)=-77.280
High
p=<.001* p=<.001*
311
conditions.
Dynamic
Glove
Low Load Mid Load High load
Sample
t(2)=3.765 t(2)=-1.582 t(2)=95.714
A
p=.064 p=.254 p=<.001*
t(2)=5.386 t(2)=37.738 t(2)=50.673
B
p=.033* p=.001* p=<.001*
t(2)=25.514 t(2)=22.431 t(2)=179.052
C
p=.002* p=.002* p=<.001*
t(2)=2.401 t(2)=-20.580 t(2)=-34.379
D
p=.138 p=.002* p=.001*
t(2)=18.172 t(2)=5.632 t(2)=21.085
E
p=.003* p=.030* p=.002*
t(2)=2.047 t(2)=6.599 t(2)=-67.194
F
p=.177 p=.022* p=<.001*
t(2)=7.281 t(2)=-44.289 t(2)=24.042
G
p=.018* p=.001* p=.002*
t(2)=-8.162 t(2)=25.873 t(2)=29.958
H
p=.013* p=.001* p=.001*
312
Thin Thick

F(3,8)=71.470 F(3,8)=23.610 F(3,8)=33.434 F(3,8)=68.383
Low
p=<.001* p=<.001* p=<.001* p=<.001*
F(3,8)=581.474 F(3,8)=113.568 F(3,8)=17.400 F(3,8)=156.675
Medium
p=<.001* p=<.001* p=<.001* p=<.001*
F(3,8)=14.975 F(3,8)=712.821 F(3,8)=65.387 F(3,8)=2.967
High
p=.001* p=<.001* p=<.001* p=.092
313
3.

Load Glove
A B C A B C
(N) Sample
Q=10.593 Q=5.096
B
p=.001* p=.027*
Q=16.394 Q=2.802 Q=0.879 Q=4.217
0.1 C
p=.001* p=.015* p=.900 p=.068
Q=4.692 Q=15.284 Q=21.086 Q=10.632 Q=5.536 Q=9.753
D
p= .043* p=.001* p=.001* p=.001* p=.019* p=.001*
Q=18.638 Q=18.112
B
p=.001* p=.001*
Q=26.423 Q=45.061 Q=17.686 Q=0.423
0.5 C
p=.001* p=.001* p=.001* p=.900
Q=12.213 Q=30.851 Q=14.210 Q=1.081 Q=19.193 Q=18.768
D
p=.001* p=.001* p=.001* p=.857* p=.001* p=.001*
Q=2.013 Q=18.952
B
p=.52 p=.001*
Q=7.279 Q=5.266 Q=20.929 Q=39.881
1 C
p=.004* p=.024 p=.001* p=.001*
Q=19.925 Q=17.912 Q=12.646 Q=41.651 Q=22.699 Q=62.579
D
p=.001* p=.001* p=.001* p=.001* p=.001* p=.001*
Load Glove
E F G E F G
(N) Sample
Q=1.458 Q=8.423
F
p=.720 p=.001*
Q=6.671 Q=25.212 Q=4.024 Q=4.399
0.1 G
p=.007* p=.026* p=.900 p=.001*
Q=415.289 Q=13.831 Q=8.618 Q=28.564 Q=20.141 Q=24.540
H
p=.001* p=.001* p=.001* p=.001* p=.082 p=.001*
Q=0.211 Q=18.112
F
p=.900 p=.001*
Q=9.922 Q=10.133 Q=19.024 Q=83.234
0.5 G
p=.001* p=.001* p=.001* p=.001*
Q=2.707 Q=2.918 Q=7.215 Q=64.210 Q=54.855 Q=28.379
H
p=.295 p=.243 p=.004* p=.001* p=.001* p=.001*
Q=19.437 Q=2.386
F
p=.001* p=.390
Q=21.652 Q=2.216 Q=0.106 Q=2.280
1 G
p=.001* p=.448 p=.900 p=.425
Q=6.621 Q=26.057 Q=28.273 Q=1.819 Q=4.205 Q=1.925
H
p=.007* p=.001* p=.001* p=.600 p=.070 p=.552
314
Dynamic
Load
Dry Wet
t(2)=-2.064 t(2)=18.621
Low p=.175 p=.003*
t(2)=10.433 t(2)=-1.951
A-E
Medium p=.009* p=.191
t(2)=-6.589 t(2)=34.541
High p=.022* p=.001
t(2)=23.696 t(2)=2.774
Low p=.002* p=.109
t(2)=17.595 t(2)=-71.294
B-F
Medium p=.003* p=<.001*
t(2)=-8.960 t(2)=-12.179
High p=.012* p=.004*
t(2)=4.266 t(2)=-37.379
Low p=.051 p=.001*
t(2)=8.662 t(2)=21.260
C-G
Medium p=.013* p=.002*
t(2)=0.532 t(2)=0.826
High p=.648 p=<.001*
t(2)=124.862 t(2)=-19.007
Low p=<.001* p=.003*
t(2)=-16.654 t(2)=10.435
D-H
Medium p=.001* p=.005*
t(2)=8.542 t(2)=-9.725
High p=.013* p=.010*
315
conditions.
Dynamic
Glove
Low Load Mid Load High Load
Sample
t(2)=-0.890 t(2)=85.889 t(2)=40.748
A
p=.468 p=<.001* p=.001*
t(2)=42.782 t(2)=110.648 t(2)=-12.226
B
p=.001* p=<.001* p=.007*
t(2)=19.715 t(2)=32.034 t(2)=10.561
C
p=.003* p=.001* p=.009*
t(2)=13.439 t(2)=-3.203 t(2)=4.387
D
p=.005* p=.085 p=.048*
t(2)=33.119 t(2)=-1.107 t(2)=8.174
E
p=<.001* p=.384 p=.015*
t(2)=-6.799 t(2)=10.540 t(2)=113.914
F
p=.021* p=.013* p=<.001*
t(2)=2.176 t(2)=61.761 t(2)=11.348
G
p=.161 p=<.001 p=.008*
t(2)=0.356 t(2)=47.580 t(2)=3.683
H
p=.756 p=<.001* p=.066
316
Appendix D – Supplementary data for Chapter Seven
D1. Friction coefficients of NBR gloves in each condition, with the different tools at each load.

Load CoF Load CoF Load CoF Load CoF Load CoF Load CoF Load CoF
1.05 0.26 1.11 0.51 1.02 0.57 0.97 0.47 0.80 0.74 1.01 0.36 1.22 1.05
(±0.05) (±0.01) (±0.09) (±0.05) (±0.04) (±0.01) (±0.07) (±0.01) (±0.16) (±0.11) (±0.03) (±0.06) (±0.11) (±0.09)
2.18 0.25 2.08 0.50 2.05 0.44 2.09 0.36 2.00 0.67 1.95 0.35 2.03 1.01
(±0.01) (±0.01) (±0.03) (±0.02) (±0.11) (±0.04) (±0.11) (±0.04) (±0.01) (±0.01) (±0.08) (±0.15) (±0.02) (±0.02)
3.01 0.25 3.03 0.48 3.02 0.43 3.05 0.38 3.03 0.66 2.90 0.35 2.98 1.02
Dry
(±0.04) (±0.01) (±0.09) (±0.04) (±0.07) (±0.03) (±0.02) (±0.01) (±0.06) (±0.04) (±0.06) (±0.08) (±0.19) (±0.21)
4.02 0.26 3.92 0.45 4.05 0.44 4.09 0.43 4.04 0.66 4.01 0.26 4.36 1.06
(±0.07) (±0.02) (±0.13) (±0.05) (±0.02) (±0.01) (±0.11) (±0.07) (±0.01) (±0.01) (±0.06) (±0.07) (±0.14) (±0.17)
4.97 0.26 5.02 0.43 5.16 0.46 4.98 0.48 5.03 0.66 4.95 0.30 5.36 1.10
(±0.15) (±0.04) (±0.11) (±0.04) (±0.17) (±0.10) (±0.01) (±0.01) (±0.04) (±0.02) (±0.04) (±0.05) (±0.25) (±0.32)
1.01 0.24 0.94 0.55 1.01 0.59 1.00 0.39 0.94 0.32 0.99 0.52 1.16 0.36
(±0.01) (±0.01) (±0.03) (±0.02) (±0.02) (±0.01) (±0.05) (±0.01) (±0.04) (±0.01) (±0.02) (±0.01) (±0.05) (±0.09)
2.10 0.26 2.03 0.55 2.02 0.49 2.00 0.33 2.00 0.24 2.08 0.24 1.98 0.38
(±0.07) (±0.02) (±0.06) (±0.03) (±0.12) (±0.04) (±0.07) (±0.02) (±0.01) (±0.01) (±0.02) (±0.01) (±0.03) (±0.02)
Alco- 2.97 0.27 3.11 0.55 3.01 0.45 2.95 0.35 2.96 0.25 3.04 0.25 3.01 0.39
hol (±0.05) (±0.02) (±0.02) (±0.01) (±0.07) (±0.03) (±0.04) (±0.02) (±0.08) (±0.02) (±0.08) (±0.02) (±0.07) (±0.21)
4.05 0.28 4.07 0.56 3.99 0.43 4.02 0.39 4.06 0.25 4.10 0.26 4.13 0.41
(±0.12) (±0.04) (±0.04) (±0.02) (±0.05) (±0.02) (±0.09) (±0.05) (±0.12) (±0.03) (±0.15) (±0.04) (±0.04) (±0.17)
4.95 0.28 4.93 0.56 5.18 0.41 5.07 0.43 4.93 0.43 5.12 0.52 5.23 0.42
(±0.29) (±0.09) (±0.10) (±0.06) (±0.10) (±0.03) (±0.03) (±0.02) (±0.10) (±0.02) (±0.04) (±0.01) (±0.12) (±0.32)
1.06 0.31 1.00 0.46 1.03 0.42 1.09 0.27 0.97 0.21 1.02 0.37 1.06 0.53
(±0.10) (±0.01) (±0.05) (±0.02) (±0.01) (±0.01) (±0.06) (±0.05) (±0.15) (±0.04) (±0.02) (±0.02) (±0.05) (±0.05)
2.02 0.26 1.96 0.47 2.03 0.44 1.99 0.35 1.90 0.25 2.03 0.24 1.95 0.33
Mix
(±0.09) (±0.02) (±0.05) (±0.02) (±0.03) (±0.01) (±0.11) (±0.05) (±0.09) (±0.01) (±0.11) (±0.05) (±0.10) (±0.09)
3.01 0.26 3.05 0.49 2.93 0.42 3.03 0.35 3.06 0.20 3.06 0.20 3.04 0.28
(±0.07) (±0.02) (±0.05) (±0.03) (±0.05) (±0.02) (±0.07) (±0.02) (±0.01) (±0.01) (±0.03) (±0.01) (±0.05) (±0.04)
317
4.00 0.28 4.00 0.50 3.99 0.40 4.01 0.33 3.94 0.17 4.08 0.16 4.02 0.28
(±0.06) (±0.02) (±0.15) (±0.08) (±0.03) (±0.01) (±0.03) (±0.01) (±0.04) (±0.01) (±0.05) (±0.01) (±0.08) (±0.06)
4.93 0.35 5.00 0.51 4.96 0.38 4.97 0.34 4.99 0.22 4.80 0.33 4.89 0.30
(±0.04) (±0.02) (±0.06) (±0.03) (±0.05) (±0.01) (±0.06) (±0.01) (±0.05) (±0.01) (±0.07) (±0.01) (±0.06) (±0.04)
1.02 0.50 0.96 0.57 1.03 0.53 0.92 0.34 1.07 0.24 1.09 0.30 0.97 0.72
(±0.03) (±0.02) (±0.04) (±0.02) (±0.05) (±0.02) (±0.04) (±0.03) (±0.03) (±0.02) (±0.02) (±0.02) (±0.05) (±0.05)
2.07 0.52 1.97 0.51 2.07 0.49 2.00 0.38 2.05 0.50 2.07 0.56 1.90 0.83
(±0.07) (±0.04) (±0.08) (±0.04) (±0.05) (±0.02) (±0.02) (±0.01) (±0.04) (±0.02) (±0.5) (±0.05) (±0.10) (±0.09)
Muci 2.99 0.52 3.06 0.47 2.95 0.48 2.78 0.36 3.08 0.49 2.96 0.50 3.04 0.82
-n (±0.10) (±0.05) (±0.07) (±0.03) (±0.09) (±0.04) (±0.16) (±0.04) (±0.05) (±0.01) (±0.03) (±0.01) (±0.05) (±0.04)
4.12 0.53 3.92 0.46 4.08 0.48 4.01 0.32 4.00 0.44 3.99 0.44 4.05 0.80
(±0.10) (±0.05) (±0.07) (±0.02) (±0.08) (±0.04) (±0.10) (±0.02) (±0.06) (±0.01) (±0.05) (±0.01) (±0.08) (±0.06)
5.12 0.53 4.99 0.43 5.09 0.48 5.17 0.28 4.98 0.40 5.04 0.39 5.03 0.79
(±0.06) (±0.03) (±0.09) (±0.03) (±0.08) (±0.04) (±0.01) (±0.01) (±0.06) (±0.01) (±0.07) (±0.01) (±0.06) (±0.04)
1.03 0.33 0.99 0.58 0.96 0.42 1.07 0.42 1.00 0.34 1.08 0.46 1.04 0.25
(±0.05) (±0.03) (±0.07) (±0.03) (±0.02) (±0.01) (±0.03) (±0.08) (±0.01) (±0.01) (±0.03) (±0.01) (±0.07) (±0.03)
1.97 0.40 1.97 0.55 1.93 0.36 1.97 0.39 1.90 0.16 2.04 0.16 2.02 0.27
(±0.10) (±0.04) (±0.13) (±0.07) (±0.07) (±0.02) (±0.08) (±0.03) (±0.03) (±0.01) (±0.05) (±0.01) (±0.08) (±0.03)
3.00 0.39 3.04 0.55 3.05 0.30 3.01 0.40 2.94 0.16 2.95 0.16 3.09 0.27
Oil
(±0.10) (±0.03) (±0.11) (±0.06) (±0.10) (±0.02) (±0.11) (±0.10) (±0.07) (±0.02) (±0.02) (±0.01) (±0.02) (±0.01)
4.12 0.37 4.08 0.56 3.95 0.27 4.12 0.41 3.95 0.16 3.94 0.16 4.25 0.28
(±0.20) (±0.06) (±0.08) (±0.05) (±0.11) (±0.01) (±0.10) (±0.06) (±0.06) (±0.02) (±0.02) (±0.01) (±0.09) (±0.03)
4.88 0.36 5.07 0.57 5.02 0.25 5.02 0.43 4.98 0.31 5.04 0.53 5.15 0.28
(±0.15) (±0.04) (±0.07) (±0.04) (±0.23) (±0.02) (±0.07) (±0.02) (±0.10) (±0.03) (±0.11) (±0.03) (±0.15) (±0.05)
0.96 0.37 0.96 0.45 0.98 0.38 0.98 0.28 0.96 0.35 0.96 0.16 0.96 0.32
(±0.06) (±0.02) (±0.05) (±0.03) (±0.02) (±0.05) (±0.05) (±0.05) (±0.05) (±0.05) (±0.05) (±0.01) (±0.03) (±0.02)
1.99 00.31 1.98 0.51 2.07 0.33 1.95 0.34 1.98 0.31 1.97 0.31 1.95 0.33
Pow- (±0.04) (±0.01) (±0.09) (±0.05) (±0.08) (±0.03) (±0.01) (±0.02) (±0.05) (±0.02) (±0.07) (±0.02) (±0.05) (±0.03)
der 2.99 0.29 2.85 0.55 2.97 0.28 3.04 0.35 2.99 0.29 2.95 0.29 3.01 0.33
(±0.09) (±0.02) (±0.14) (±0.09) (±0.03) (±0.05) (±0.01) (±0.03) (±0.04) (±0.07) (±0.06) (±0.01) (±0.21) (±0.01)
3.98 0.28 4.01 0.57 3.97 0.24 3.93 0.35 3.97 0.29 3.99 0.29 3.97 0.33
(±0.16) (±0.04) (±0.06) (±0.05) (±0.18) (±0.05) (±0.03) (±0.05) (±0.06) (±0.03) (±0.02) (±0.12) (±0.06) (±0.03)
318
5.05 0.27 5.14 0.58 5.07 0.22 5.04 0.35 4.94 0.26 5.08 0.21 4.90 0.33
(±0.07) (±0.02) (±0.05) (±0.06) (±0.11) (±0.01) (±0.03) (±0.01) (±0.09) (±0.03) (±0.10) (±0.01) (±0.08) (±0.02)
1.05 0.22 1.01 0.7 1.04 0.37 0.96 0.28 1.05 0.23 1.02 0.34 1.02 0.42
(±0.09) (±0.02) (±0.10) (±0.04) (±0.08) (±0.09) (±0.04) (±0.02) (±0.08) (±0.10) (±0.02) (±0.02) (±0.03) (±0.01)
2.11 0.23 2.00 0.39 2.08 0.32 1.94 0.27 1.96 0.75 2.03 0.75 1.96 0.43
(±0.01) (±0.01) (±0.07) (±0.03) (±0.03) (±0.05) (±0.15) (±0.02) (±0.025) (±0.10) (±0.02) (±0.01) (±0.04) (±0.02)
Wat 3.08 0.23 3.08 0.40 3.08 0.28 3.03 0.29 2.98 0.69 3.07 0.69 2.94 0.46
-er (±0.05) (±0.01) (±0.09) (±0.04) (±0.08) (±0.04) (±0.01) (±0.01) (±0.08) (±0.04) (±0.04) (±0.03) (±0.04) (±0.02)
4.03 0.22 3.98 0.40 4.16 0.24 4.14 0.30 3.97 0.63 4.07 0.62 4.00 0.49
(±0.06) (±0.01) (±0.05) (±0.02) (±0.07) (±0.17) (±0.01) (±0.06) (±0.06) (±0.02) (±0.02) (±0.13) (±0.04) (±0.03)
5.05 0.21 5.04 0.40 5.09 0.23 5.03 0.33 5.07 0.19 5.07 0.35 4.94 0.52
(±0.04) (±0.01) (±0.07) (±0.03) (±0.15) (±0.13) (±0.01) (±0.05) (±0.09) (±0.03) (±0.03) (±0.02) (±0.02) (±0.01)
319
D2. Friction coefficients of NRL gloves in each condition, with the different tools at each load.

Load CoF Load CoF Load CoF Load CoF Load CoF Load CoF Load CoF
1.04 1.23 1.19 1.71 1.09 1.78 1.10 1.62 0.93 1.35 0.97 1.03 1.18 2.15
(±0.04) (±0.09) (±0.07) (±0.12) (±0.02) (±0.04) (±0.08) (±0.12) (±0.03) (±0.07) (±0.01) (±0.03) (±0.04) (±0.03)
2.12 1.60 1.89 1.86 2.00 1.43 2.02 1.49 2.09 1.25 1.10 1.18 2.23 2.22
Dry (±0.02) (±0.03) (±0.07) (±0.08) (±0.13) (±0.23) (±0.07) (±0.07) (±0.02) (±0.04) (±0.07) (±0.12) (±0.16) (±0.07)
2.95 1.59 3.03 1.32 3.12 1.23 3.11 1.39 3.02 1.19 3.01 1.29 3.02 2.14
(±0.06) (±0.10) (±0.08) (±0.07) (±0.05) (±0.07) (±0.08) (±0.06) (±0.02) (±0.05) (±0.06) (±0.09) (±0.06) (±0.08)
4.04 1.53 4.05 1.46 4.05 1.58 4.29 1.23 4.00 1.14 3.97 1.14 3.90 1.84
(±0.06) (±0.07) (±0.05) (±0.04) (±0.16) (±0.20) (±0.13) (±0.08) (±0.09) (±0.12) (±0.03) (±0.03) (±0.05) (±0.08)
5.08 1.47 5.02 1.12 5.18 1.56 5.26 0.99 5.02 1.05 4.98 0.70 5.35 1.67
(±0.12) (±0.14) (±0.03) (±0.02) (±0.26) (±0.29) (±0.12) (±0.06) (±0.08) (±0.10) (±0.08) (±0.09) (±0.32) (±0.66)
1.08 0.18 0.97 0.58 1.03 0.39 0.24 0.32 1.02 0.33 1.12 0.19 1.04 0.43
(±0.04) (±0.01) (±0.04) (±0.03) (±0.02) (±0.01) (±0.10) (±0.01) (±0.01) (±0.04) (±0.03) (±0.01) (±0.02) (±0.02)
2.10 0.24 1.95 0.66 2.03 0.28 0.27 0.35 2.00 0.24 1.88 0.24 2.07 0.46
Alco
(±0.04) (±0.01) (±0.05) (±0.03) (±0.01) (±0.01) (±0.07) (±0.01) (±0.03) (±0.11) (±0.11) (±0.03) (±0.04) (±0.02)
hol
3.03 0.25 2.98 0.65 3.10 0.23 0.24 0.32 2.99 0.25 2.95 0.25 3.07 0.46
(±0.09) (±0.02) (±0.17) (±0.10) (±0.12) (±0.01) (±0.06) (±0.01) (±0.05) (±0.03) (±0.01) (±0.01) (±0.04) (±0.02)
4.07 0.25 4.07 0.62 4.01 0.20 0.21 0.28 3.88 0.26 4.01 0.25 4.00 0.45
(±0.16) (±0.04) (±0.08) (±0.04) (±0.06) (±0.01) (±0.13) (±0.06) (±0.02) (±0.15) (±0.14) (±0.04) (±0.28) (±0.12)
4.97 0.24 5.05 0.61 5.14 0.20 0.19 0.28 3.88 0.25 4.81 0.77 5.15 0.44
(±0.05) (±0.01) (±0.12) (±0.06) (±0.02) (±0.01) (±0.06) (±0.02) (±0.02) (±0.07) (±0.07) (±0.02) (±0.05) (±0.02)
1.05 0.32 0.97 0.43 0.94 0.33 0.98 0.28 1.02 0.28 0.99 0.33 1.02 0.42
(±0.05) (±0.01) (±0.03) (±0.01) (±0.01) (±0.03) (±0.01) (±0.02) (±0.01) (±0.01) (±0.05) (±0.01) (±0.03) (±0.01)
Mix 2.08 0.24 2.02 0.38 2.00 0.33 2.01 0.27 1.97 0.25 2.02 0.25 1.98 0.31
(±0.06) (±0.01) (±0.14) (±0.06) (±0.01) (±0.02) (±0.04) (±0.07) (±0.01) (±0.04) (±0.07) (±0.01) (±0.08) (±0.01)
3.01 0.20 2.93 0.39 2.93 0.29 2.98 0.24 3.06 0.20 3.02 0.20 3.03 0.24
(±0.11) (±0.01) (±0.01) (±0.01) (±0.01) (±0.01) (±0.01) (±0.04) (±0.01) (±0.01) (±0.02) (±0.01) (±0.11) (±0.01)
3.94 0.17 3.93 0.41 3.86 0.26 4.05 0.21 4.01 0.17 4.13 0.16 3.93 0.20
(±0.08) (±0.01) (±0.09) (±0.04) (±0.01) (±0.01) (±0.01) (±0.01) (±0.01) (±0.01) (±0.11) (±0.01) (±0.01) (±0.01)
320
5.02 0.14 5.11 0.41 4.99 0.24 4.95 0.21 5.02 0.12 4.92 0.32 4.91 0.18
(±0.08) (±0.01) (±0.11) (±0.05) (±0.01) (±0.01) (±0.01) (±0.06) (±0.01) (±0.01) (±0.10) (±0.01) (±0.10) (±0.01)
1.11 0.56 0.93 0.78 0.94 0.44 1.21 0.43 1.00 0.47 1.10 1.10 1.11 0.97
(±0.02) (±0.02) (±0.04) (±0.04) (±0.05) (±0.03) (±0.09) (±0.04) (±0.02) (±0.02) (±0.08) (±0.06) (±0.05) (±0.06)
2.03 0.57 1.99 0.85 2.08 0.38 1.98 0.45 1.94 0.57 1.95 0.57 1.97 0.97
Muci
(±0.09) (±0.04) (±0.04) (±0.13) (±0.06) (±0.02) (±0.05) (±0.02) (±0.03) (±0.07) (±0.05) (±0.02) (±0.10) (±0.08)
n
3.02 0.50 2.92 0.83 2.97 0.34 3.08 0.46 2.99 0.50 3.07 0.49 3.01 0.85
(±0.05) (±0.01) (±0.10) (±0.08) (±0.08) (±0.02) (±0.07) (±0.07) (±0.02) (±0.05) (±0.12) (±0.03) (±0.12) (±0.06)
4.00 0.44 4.01 0.80 4.04 0.29 3.98 0.46 3.98 0.44 4.21 0.43 4.05 0.74
(±0.10) (±0.02) (±0.06) (±0.04) (±0.04) (±0.01) (±0.02) (±0.07) (±0.01) (±0.01) (±0.09) (±0.02) (±0.12) (±0.05)
4.99 0.39 5.09 0.77 5.00 0.34 5.00 0.46 4.90 0.54 5.14 1.03 5.03 0.67
(±0.09) (±0.02) (±0.05) (±0.03) (±0.13) (±0.01) (±0.06) (±0.11) (±0.02) (±0.01) (±0.08) (±0.01) (±0.06) (±0.02)
1.07 0.22 1.03 0.29 1.00 0.22 1.00 0.22 1.03 0.22 1.01 0.68 1.05 0.09
(±0.03) (±0.01) (±0.09) (±0.05) (±0.02) (±0.01) (±0.01) (±0.01) (±0.08) (±0.01) (±0.02) (±0.01) (±0.03) (±0.01)
2.13 0.16 1.98 0.39 1.98 0.24 1.88 0.24 2.00 0.16 2.26 0.46 2.13 0.07
Oil (±0.15) (±0.02) (±0.12) (±0.05) (±0.04) (±0.01) (±0.07) (±0.02) (±0.03) (±0.01) (±0.66) (±0.10) (±0.06) (±0.01)
2.91 0.17 3.07 0.39 2.90 0.23 3.00 0.23 2.97 0.17 2.67 0.36 3.10 0.07
(±0.05) (±0.01) (±0.18) (±0.07) (±0.13) (±0.02) (±0.14) (±0.02) (±0.08) (±0.01) (±0.57) (±0.09) (±0.09) (±0.01)
4.00 0.16 4.03 0.38 3.89 0.20 4.15 0.20 4.00 0.17 4.11 0.27 4.06 0.08
(±0.08) (±0.02) (±0.08) (±0.03) (±0.15) (±0.02) (±0.07) (±0.02) (±0.23) (±0.05) (±0.13) (±0.03) (±0.08) (±0.01)
5.09 0.18 5.00 0.37 5.03 0.22 4.86 0.21 4.96 0.18 4.97 0.29 5.08 0.09
(±0.14) (±0.04) (±0.03) (±0.01) (±0.06) (±0.01) (±0.14) (±0.01) (±0.06) (±0.01) (±0.07) (±0.02) (±0.02) (±0.01)
0.98 0.39 1.09 0.51 1.05 0.29 1.01 0.39 1.00 0.39 0.99 0.36 1.04 0.29
(±0.06) (±0.01) (±0.07) (±0.06) (±0.07) (±0.03) (±0.05) (±0.02) (±0.05) (±0.01) (±0.05) (±0.01) (±0.03) (±0.01)
1.87 0.32 1.93 0.61 1.93 0.31 1.94 0.40 2.06 0.31 1.92 0.32 2.03 0.23
Pow
(±0.06) (±0.01) (±0.04) (±0.03) (±0.04) (±0.01) (±0.07) (±0.02) (±0.03) (±0.02) (±0.04) (±0.01) (±0.10) (±0.02)
der
2.94 0.29 3.02 0.62 3.00 0.27 2.86 0.38 3.11 0.29 3.00 0.29 3.07 0.21
(±0.04) (±0.01) (±0.08) (±0.05) (±0.06) (±0.01) (±0.05) (±0.02) (±0.03) (±0.02) (±0.03) (±0.01) (±0.03) (±0.01)
4.00 0.29 3.95 0.61 3.92 0.24 3.99 0.35 3.93 0.29 3.95 0.29 3.97 0.21
(±0.02) (±0.01) (±0.11) (±0.06) (±0.15) (±0.02) (±0.04) (±0.01) (±0.07) (±0.02) (±0.08) (±0.02) (±0.09) (±0.02)
4.99 0.29 4.99 0.59 4.96 0.24 5.01 0.34 5.01 0.32 4.80 0.32 5.08 0.21
(±0.09) (±0.03) (±0.03) (±0.01) (±0.05) (±0.01) (±0.12) (±0.03) (±0.04) (±0.01) (±0.04) (±0.01) (±0.20) (±0.04)
321
1.03 0.61 0.94 0.71 1.08 0.45 1.03 0.39 0.99 0.45 0.98 0.97 1.01 1.28
(±0.03) (±0.03) (±0.02) (±0.01) (±0.01) (±0.01) (±0.04) (±0.01) (±0.03) (±0.03) (±0.05) (±0.06) (±0.02) (±0.05)
2.09 0.75 1.98 0.67 2.06 0.39 2.00 0.34 1.99 0.75 1.99 0.75 1.97 1.55
Wat
(±0.08) (±0.05) (±0.09) (±0.06) (±0.03) (±0.01) (±0.07) (±0.02) (±0.07) (±0.05) (±0.07) (±0.04) (±0.05) (±0.08)
er
3.04 0.69 3.00 0.63 2.95 0.33 3.01 0.35 2.97 0.69 2.96 0.69 3.16 1.46
(±0.13) (±0.06) (±0.07) (±0.04) (±0.03) (±0.01) (±0.14) (±0.06) (±0.02) (±0.01) (±0.08) (±0.04) (±0.13) (±0.15)
4.00 0.63 4.08 0.61 4.11 0.28 3.97 0.37 3.82 0.64 3.99 0.63 4.20 1.37
(±0.09) (±0.04) (±0.06) (±0.03) (±0.07) (±0.01) (±0.07) (±0.03) (±0.12) (±0.05) (±0.03) (±0.01) (±0.10) (±0.11)
4.95 0.57 4.89 0.58 5.11 0.26 5.04 0.40 5.12 0.35 4.97 0.99 5.00 1.31
(±0.13) (±0.04) (±0.09) (±0.05) (±0.08) (±0.01) (±0.01) (±0.01) (±0.09) (±0.03) (±0.11) (±0.04) (±0.09) (±0.08)
322

Assstment of Gloves

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The Assessment of Medical Gloves for In-Situ

A thesis submitted in partial fulfilment of the requirements for the degree of

The University of Sheffield

1st February 2021

Adsorbed: Substance chemically adhered to a surface of a material

• Understanding the tribological interactions between gloves and a variety of surfaces is

1.3 Novelty and Impact

1.4 Structure of thesis

2.2 Medical glove use

2.3 Glove Materials and market trends

Figure 2.2. Structure of the polyisoprene monomer making up the NRL.

2.4 Glove Manufacturing

2.4.1 Manufacturing Process

Figure 2.5. Glove formed on porcelain mould.

2.4.2 Post-dip processing

NaClO + H2O  Na++ HClO + OH

The hypochlorous acid then further dissociates to form chlorine (Cl2):

HClO + H3O++ Cl─  Cl2 + 2H2O

2.5 Glove Standards

Before Aging After Aging

ASTM 6 ≥0.05 ≥500 ≥14.0 ≥400 ≥14

2.6 Medical glove assessments

2.6.1 Tactile Sensitivity

Similar results between bare finger and

Phillips, Birch, and Ribbans Two-point discrimination Roughness

Han, Kim, Moon, et al. (78)

Two-point discrimination and

Two-point discrimination and

No significant difference observed

Mylon et al. (70)

Simulated Medical Examination Tactile

Figure 2.9. Crawford small parts dexterity test (24 × 23 cm).

Nelson and Mital (74) 20 NRL Paper Cutting No effect on dexterity

Mylon et al. (8) 19 NRL and NBR Suturing No effect on dexterity

No effect on dexterity, although

No effect on dexterity, although

Fry et al. (77) 53 Not Stated Purdue Pegboard No effect on dexterity

Park et al. (63)

Berger, Krul, and Daanen

Johnson et al. (75) Manual dexterity reduced when

Gloves reduced dexterity in the

Medical Glove Surface Interaction

Disposable scalpels are

2.6.4 Double gloving

2.7 Size and fit

Finger length (cm) Palm circumference (cm) Size

2.8 Paper grading

(2) Number of participants/samples: does the study have a respectable number of

(3) Statistical analysis: has a statistical analysis been conducted?

6) Glove material: have multiple glove materials been studied?

Figure 2.10. Grading of glove related papers to assess gaps in knowledge.

Participants were approached by e-mail, as well as verbal communication, aimed at professions

1. What is your job title?

Figure 3.1. Respondents of questionnaire by job sector (n=172).

3.4.2 Glove materials

Figure 3.2. Gloves routinely worn by respondents (n=172).

3.4.3 Contaminants contacted

a) Clinical b) Dental Care

Figures 3.5 (a-f). Breakdown of all contaminants contacted by job sector.