Journal of Natural Fibers
ISSN: 1544-0478 (Print) 1544-046X (Online) Journal homepage: http://www.tandfonline.com/loi/wjnf20
Recycling of cotton and polyester fibers to produce
nonwoven fabric for functional sound absorption
material
Sakthivel Santhanam, Bharani M., Selamu Temesgen, Desalegn Atalie &
Gashaw Ashagre
To cite this article: Sakthivel Santhanam, Bharani M., Selamu Temesgen, Desalegn Atalie &
Gashaw Ashagre (2018): Recycling of cotton and polyester fibers to produce nonwoven fabric for
functional sound absorption material, Journal of Natural Fibers
To link to this article: https://doi.org/10.1080/15440478.2017.1418472
Published online: 09 Jan 2018.
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Date: 09 January 2018, At: 13:17
JOURNAL OF NATURAL FIBERS
https://doi.org/10.1080/15440478.2017.1418472
Recycling of cotton and polyester fibers to produce nonwoven
fabric for functional sound absorption material
Sakthivel Santhanama, Bharani M.a, Selamu Temesgena, Desalegn Atalieb,
and Gashaw Ashagreb
a
Department of Textile Engineering Kombolcha, Institute of Technology,Wollo University, Kombolcha, Ethiopia;
Ethiopian Institute of Textile and Fashion Technology, Bahir Dar University, Bahir Dar, Ethiopia
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b
ABSTRACT
KEYWORDS
Recycled fibers are commonly used in dissimilar applications and one of the
most important applications is sound absorption. Recycled fiber nonwovens
currently are in greater demands in industries because of their advantages
such as low cost, biodegradability, acceptable mechanical and physical
properties, and so on. Sound absorption materials, renewable, and ecofriendly nonwovens have been developed using recycled cotton and polyester fibers. This research provides a contribution to the body of knowledge
on the sound absorption properties of nonwovens using recycled fibers
which contain cotton and polyester by means of spun-laid technique and
provides a better understanding of the effects of a number of manufacturing processes on nonwovens noise control performance and also contributes to the wider adoption of nonwovens as sound absorbers. The sound
absorption coefficients were measured according to ASTM E 1050 by an
impedance tube method. The results revealed that the average of the
sound absorption coefficients increased with the thickness of the nonwovens, but decreased with the nonwoven fabric density.
Recycling; cotton/polyester;
spun laid; nonwoven; sound
absorption; non woven
density
关键词
回收; 棉/涤; 纺丝成网; 无
纺布; 声吸䔶; 非织造密
度。
摘要
再生纤维在不同的应用中广泛使用，其中最重要的应用之一是吸音。再生
纤维非织造布目前，因其具有成本低、可生物降解的优势在行业的要求越
来越高，可接受的机械和物理性能等。吸声材料，可再生能源和环保无纺
布已使用再生棉和聚酯纤维的开发。这项研究提供了对使用再生纤维包括
棉、纺涤纶非织造布放技术手段的吸声性能的知识体的贡献，提供了一个
更好地了解一个制造工艺对非织造布的噪音控制性能的影响，也有助于更
广泛的采用无纺布的声音吸收剂。吸声系数由ASTM E 1050通过阻抗管法测
量。结果表明，吸声系数的平均值随非织造布厚度的增加而增加，但随着
非织造布密度的增大而减小。
Introduction
For centuries, fibers have been reclaimed from end-of-life textiles and made into textile products,
which has become a well-proven and effective way of recycling. The natural availability of reproducing fibers is limited and people have always tried to control consumption. In times of textile raw
material scarcity, the recycling of end-of-life textiles became a necessity, and craftsmen or even the
recycling industry tried to achieve higher output this way. Textile waste was looked upon as a
valuable source of raw material. Resources to make primary synthetic fibers are becoming less and
less and the world population is rising, so it is clear that textile recycling needs to stay on the agenda
CONTACT Sakthivel Santhanam
sakthi.texpsg@gmail.com
Department of Textile Engineering Kombolcha, Institute of
Technology, Wollo University, Kombolcha, Ethiopia-208.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/wjnf.
© 2018 Taylor & Francis Group, LLC
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2
S. SANTHANAM ET AL.
(Braun, Levy, and Sifniades 1999, Realff, Ammons, and Newton 2004). This is what makes it
necessary to develop processes to design textiles that are easy to recycle. Designers are expected to
feel responsible for production waste and for end-of-life products. This is what they have been faced
with for a long time. Both in the clothes-making industry and in enterprises such as processing and
finishing of textiles, production waste is generally defined and much is suitable to be reused. For
end-of-life industrial textiles, including mainly technical textiles, recycling systems are generally not
yet sufficient (Brown 2001). One of the reasons that there are only few vehicle fields in which wereuse them. However, if they were designed to be easily recycled, such fields could well be found. With
the significant production of waste fibrous materials, different companies are looking for applications where waste materials may represent an added-value material (Mwaikambo 2006). Textiles for
use in the automotive industry are often composites. This is how they can best achieve the
characteristics or the functionality required. Cost is also of interest in this context (Realff,
Ammons, and Newton 2004). The textiles-based stamped parts used in the vehicle interior are
typical representatives. High-grade decorative materials hide a blend of a variety of fibers. This is
what the structural strength depends upon. Decorative and base materials are generally inseparably
bonded by means of gluing the full surface to be bonded. The whole system serves to stop sound
waves resulting from the car body, in particular from the front wall of the engine compartment and
the bottom plate of the interior. Noise control applications of nonwoven fabrics include wall
claddings, acoustic barriers and acoustic ceilings, passenger vehicle noise absorbers, and various
others. Nonwoven fabrics made from recycled fibers can also be more advantageous in terms of
environmental friendliness compared to conventionally used polyurethane foams which cannot be
recycled and are produced with environmental damaging manufacturing methods. Kozłowski et al.
(2008) developed nonwoven from recycled fibers that can be applied in buildings as a filling and
facing insulation materials. Structural and insulation materials made of synthetic raw materials (e.g.
polyester and polypropylene) ensure full and active “breathing” of the whole structure element
giving users a real feeling of building comfort. This more environment-friendly composite that can
be compression molded into a wide range of parts has a greater bending stiffness, is more resistant to
fire, less expensive and without the odor problems that accompany many recycled fibers by (Bradley
and Greer 2011) formation of composites by using reclaimed polyester fibers and biodegradable melt
blown (PVA, PLA, and PEA). Polymers as main components have been studied by Muller and
Krobjilowski (2004).
Experimental methodology
Materials
Current research focuses on the development of a waste-free system to make textile-based stamped
parts for the automotive industry. This production process is characterized by high quantities of
waste which, so far, can hardly or not at all be reused. Yet textile-based thermoplastic composites
show good material potential and are suited to recycling (Braun, Levy, and Sifniades 1999, Brown
2001). In this research work, the recycled cotton and polyester materials are used to make the blends
of recycled fiber with spun-laid techniques.
The purpose of this study is to provide a better understanding of acoustical properties of
nonwovens, and to model the noise control behavior in terms of material and treatment parameters.
Treatment of the noise receiver may not always be a practical solution, as each receiver must be
treated individually. Hence, treatment of the noise path is conceptually the simplest and the most
common approach in noise reduction (Braccesi and Bracciali 1998). Secondary noise control
constitutes enclosure of noise sources, vibration isolation, noise barrier, noise absorption, reactive
and dissipative silencing. The present paper focuses on the absorption phenomenon of sound.
Nonwoven fabrics, which are fibrous porous materials, have an important use in noise reduction.
Nonwovens have some advantages over cellular absorbers, that is foams, such as low production
JOURNAL OF NATURAL FIBERS
3
costs and low specific gravity. Nonwovens can also be more environmental friendly than conventional sound absorbers of polyurethane foams which are unable to be recycled and have environmental damaging manufacturing methods. Human ears can detect sound waves in the frequency
range of 16 Hz to 20,000 Hz generally. The range below the audible range is called the infrasonic
range, and the range above the upper limit of hearing is called the ultrasonic range. Whereas there is
no lower limit for infrasonic range, the upper limit of ultrasonic range is of the order of 1013 Hz
depending on the medium. At 1013 Hz, the wavelengths reduce to values which are comparable to
the distances between atoms in liquids and solids (Saha 1994).
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Measuring the sound absorption coefficient in recycled nonwoven fabric
The image 1 shows measuring the sound absorption of recycled nonwoven fabrics. According to
ASTM E 1050, the shape and size of each specimen were the same as the tube cross-section (a
circular form, 40 mm in diameter). The normal incident sound absorption coefficients (α) were
measured by an impedance tube, which was kindly provided by Automotive Research and Testing
Center (ARTC, Taiwan). The mechanisms of the instrument are shown in image 1. The arithmetic
average (α) of sound absorption coefficients over six frequencies 125, 250, 500, 1000, 2000, and
4000 Hz was calculated by
α¼
α125 þ α250 þ α500 þ α1000 þ α2000 þ α4000
6
(1)
SEM analysis of recycled cotton and polyester fibers
The image 2 shows the recycled fibers nonwoven samples perimeters measured with scalex plan
wheel XLU, by using SEM photograph of the reclaimed nonwoven fabrics. The recycled cotton and
polyester fibers nonwoven samples are measured three times and final average values were taken as a
fiber perimeter. The surface area of the fibers was calculated by multiplying the perimeter and the
total fiber length in the fabric. The surface area of the non fabrics was obtained by 25 × 4 × 25 × 4.
Results and discussions
The sound absorption reclaimed nonwoven fabrics processed at 180°C for 20 min and its composition of recycled PET/Cotton fragments is 50/50 with 4 mm in mesh diameter. Sound absorption
coefficient can be determined by the given equation.
Image 1. The apparatus and instrumentation of the impedance tube.
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4
S. SANTHANAM ET AL.
Image 2. SEM photographs of recycled nonwoven fabrics made from recycled cotton/polyester fibers.
αn ¼
Sound energy absorbed b a surface
Sound energy incident in that surface
αn ¼
1
Energy reflected
Energy incident
(2)
(3)
Table 1 shows that the sound absorption coefficient varies from zero (0) to one (1). Sound
absorption performance is a function of frequency and is performed generally with the increase in
frequency. Performance improves with the increase in thickness. Material thickness should be at least
1/10 wavelength of sound to justify the use (i.e., offer any benefit) and ¼ wavelength of sound to be
effective. Sound absorption coefficient is affected by parameters of material such as porosity,
thickness, density, air space between the absorber and the wall, perforation, and facing. The same
finding was observed by (Saha 1994; Shoshani 1990) Shoshani and Yakubov (2000). A nonwoven
web to have a high sound absorption coefficient, porosity should increase along the propagation of
the sound wave. Figure 1 presents a typical curve of the sound absorption coefficient as a function of
the sound frequency for the recycled nonwovens. As the nonwovens consisted of a melted polyester
nonwoven granules, fragments, and fibers, the recycled nonwoven porous structure possessed
Figure 1. Sound absorption coefficient recycled nonwovens.
Green line: 20 mm thickness.
Black line: 40 mm thickness.
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JOURNAL OF NATURAL FIBERS
5
excellent performance for absorption of high-frequency sound waves, especially above 2000 Hz.
However, the application of the reclaimed nonwovens for low-frequency (1000 Hz) sound wave
absorption is restricted. One of the most important qualities that influence the sound absorbing
characteristics of a fibrous material is the specific flow resistance per unit thickness of the material.
The characteristic impedance and propagation constant, which describes the acoustical properties of
porous materials, are governed to a great extent by flow resistance of the material. Fibers interlocking
in nonwovens are the frictional elements that provide resistance to acoustic wave motion. In general,
when sound enters these materials, its amplitude is decreased by friction as the waves try to move
through the tortuous passages. The same trend was observed by Fung and Hardcastle (2001).
The influence of nonwoven’s thickness on the sound absorption coefficient is shown in Figure 2,
and the values of the sound absorption coefficients at the six frequency and their averages are given
in Table 1. It found that increasing thickness obviously improved the sound absorption efficiency of
the recycled nonwoven samples at medium and low frequency, and also the value of α. In practice,
this kind of characteristic can usually be used to redeem the shortcomings of the porous structure for
sound absorption. The thicknesses of the nonwoven material are the most influencing factor on their
sound absorbing capacity. The thickness of nonwoven is less than 3.5mm little sound absorption is
achieved, if the thickness is more 9.03mm best sound absorption is achieved. The same finding was
observed by Shoshani (1990) and Fung and Hardcastle (2001).
Figure 3 shows the influence of nonwoven materials density on the sound absorption coefficient.
The sound absorption efficiency of the nonwoven samples was decreased as the nonwoven density
increases, especially for medium- and high-frequency sound wave. The density of recycled nonwoven is 0.144–0.174g/cm3 the increase of sound absorption values in the middle and higher
frequency as the density of the nonwoven samples were increased. The number of fibers increases
per unit area when the apparent density is large. The energy losses increase as the surface friction
increases, thus, the sound absorption coefficient increases. Thus most of the waves are absorbed
Figure 2. The influence of recycled nonwoven thickness on the sound absorption coefficient.
Green line: 20 mm thickness
Black line: 40 mm thickness
Red line: 50 mm thickness
Violet line: 70 mm thickness
Table 1. The sound absorption coefficients of the six frequencies and their averages of the recycled
nonwovens.
Thickness
In mm
20
40
50
70
Frequency (Hz)
α 125
0.11
0.12
0.11
0.20
α 250
0.23
0.26
0.31
0.35
α 500
0.45
0.56
0.64
0.68
α 1000
0.56
0.64
0.72
0.78
α 2000
0.64
0.66
0.74
0.86
α 3000
0.86
0.90
0.94
0.96
Α
0.475
0.523
0.573
0.638
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S. SANTHANAM ET AL.
Figure 3. The influence of recycled nonwoven density on the sound absorption coefficient.
Green line: 20 mm thickness
Black line: 40 mm thickness
Red line: 50 mm thickness
Violet line: 70 mm thickness
rather than reflected. To make the recycled nonwoven structure more compact, the interconnected
voids in the nonwovens are relatively decreased with increasing nonwoven density. Most of the
incident sound waves are reflected, rather than absorbed. In this research, recycled polyester and
cotton in the nonwovens have the effect on the sound absorption efficiency. The sound absorption
coefficients are a little decreased on the medium sound frequency (1000–2000 Hz). The same results
were obtained by Vaughn, Boston, and Tascan (2003) and Wu et al. (1996).
Comparison of reclaimed nonwoven and thermo plastic polyurethane honey comb structure
In this research work, a comparison of sound absorption measurement for recycled nonwoven materials
based on the specifications of the sound absorption materials has been developed. This same method has
been used to measure the thermo plastic polyurethane honey comb structure and alternative proposed
materials, the recycled cotton/polyester nonwovens. The results showed that the recycled cotton/polyester
nonwovens are more resilient than tested thermo plastic polyurethane honey comp structure. Indeed, this
structure enables a vertical orientation of fibers; this vertical orientation of fibers has the effect to provide
maximum resilience to the material. On the other hand, it has been shown that the recycled nonwovens
dissipate more sound absorption than thermoplastic polyurethane honey comb structure. This result has
demonstrated the ability of the fibrous structure to be reorganized under compression stress. All these
results underline the ability of this reclaimed nonwoven structure materials to replace polyurethane foam
in sustainability purpose. The same findings were observed by Koizumi, Tsujiuchi, and Adachi (2002).
Conclusion
Consider the ecological issues and the possible market development for the environmentally
compassionate recycled cotton/polyester nonwoven materials as sound absorption. In this research
work the recycled cotton and polyester fibers are used to make the blends of reclaimed fiber web
with spun-laid techniques to produce nonwoven fabrics. The recycled fibers nonwoven samples
perimeters are measured with scalex plan wheel XLU, by using SEM photograph of the recycled
nonwoven fabrics. The surface area of the recycled non fabrics thus obtained is 25 × 4 × 25 × 4. The
recycled nonwovens samples were tested for sound absorption by ASTM E 1050. The results exposed
that the porous recycled nonwovens possess excellent performance in absorption of high-frequency
JOURNAL OF NATURAL FIBERS
7
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sound waves, especially above 2000 Hz. The sound absorption efficiency of the recycled nonwoven
samples at medium and low frequency can be enhanced evidently by increasing the thickness.
However, it is decreased, at the same time as the recycled nonwoven density is increased. The
density of recycled nonwoven is 0.144–0.174g/cm3 it has been concluded that the thickness decreases
with increasing material density. The comparison was made of sound absorption measurement for
recycled nonwoven materials and thermo plastic polyurethane honey comb structure. The results
exposed that the recycled nonwovens dissipate more sound absorption than thermoplastic polyurethane honey comb structure. The acoustical properties of these recycled nonwoven materials are
useful for the proper application in products such as sound barriers, walls, road surfaces and used as
interior linings materials for auditoriums, halls, apartments, automotives, aircrafts, and ducts and
encloses for noise equipments and insulations for machineries.
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