Fiber-Reinforced-Polymer (FRP)

Materials

Made By:
Kirtika Gupta
MCI
 WHAT ARE FRP COMPOSITES?
• Fiber Reinforced Polymers (FRP), also known as “composites” are materials composed of
fiber reinforcements and a polymer resin. The reinforcements impart strength and stiffness,
while the resin is an adhesive matrix that bonds the fibers.
• In the finished part, the resin matrix transfers applied loads to the reinforcing fibers and
protects the fibers from environmental attack.

High Strength Dimensional Stability

Light Weight Part Consolidation
Corrosion Resistance Low Thermal Conductivity
Durability Good Fire-retardant Properties
Design Flexibility Reproducibility

• The properties of FRP pipes can be varied by changing the ratio of the raw materials.
• Many types of resins, reinforcements, core materials, and additives can be combined to
design very specific properties within FRP products.
Types of Fibers used in Fiber Reinforced Composites:

1. Glass fibers

2. Carbon fibers

3. Aramid fibers
 Glass Fiber – Fabrication

• Made by mixing silica sand, limestone, folic acid and other minor ingredients.
• The mix is heated until it melts at about 1260°C.
• The molten glass is then allowed to flow through fine holes
in a platinum plate.
• The glass strands are cooled, gathered and wound.
• The fibers are drawn to increase the directional strength.
• The fibers are woven into various forms for use in composites.
• Glass is generally a good impact resistant fiber but weighs
more than carbon or aramid.
Bundle of Glass Fibers
Effect of Different Weaves of Glass Fiber:-

The plain weave fabric –

• Having square setting i.e. equal number per inch of ends.
• Employed where uniformity in strength is desired.

8-shaft satin weave –

• Each weft yarn goes under one and over seven warp yarns.
• Used in heavier fabrics when lamination calls for high strength in all direction and where a
smooth surface and decorative appearance are desired.

Unidirectional weave –
• When maxi mum strength in one direction is required at a maximum weight.

*The strength of a satin weave fabric is comparatively greater than of a plain weave fabric.

Different weaves of glass fiber

 Physical and Mechanical Properties of Glass Fiber Types
Tensile
Glass Density, Modulus, Percent
Composition Strength,
Fiber type (g/cm3) GPa Elongation
MPa
High Alkali Content-Alkali-lime glass with
A-glass 2.44 3300 72 4.8
little or no boron oxide
AR-glass Alkali Resistant 2.7 1700 72 2.3
Chemical Resistant-alkali-lime glass with
C-glass 2.56 3300 69 4.8
high boron oxide
Good Dielectric Properties-borosilicate
D-glass 2.11 2500 55 4.5
glass
Good Electrical Properties-Alumino-
E-glass 2.54 3400 72 4.7
borosilicate glass
ECR- Use in Acid Environments-Alumino-lime
2.72 3400 80 4.3
glass silicate
High Mechanical Strength-Alumino silicate
R-glass 2.52 4400 86 5.1
glass without MgO and CaO
High Mechanical Strength-Alumino silicate
S-glass 2.53 4600 89 5.2
glass without CaO but with high MgO
 Applications of GFRP
• GFRP can be used for both interior and exterior fixtures in a variety of shapes,
styles, and textures.
• Architectural Uses – Due to its translucent nature and less weight, it is used as a
roofing material in various places.
• Water Distribution
• Waste Water
• Cooling System
• Process Lines for Plants
• Food and Chemical Storage
• Sea Lines and River Crossings
 Carbon Fibers – Classification

Based on carbon fiber properties –

• Ultra-high-modulus, type UHM (modulus >450GPa)
• High-modulus, type HM (modulus between 350-450GPa)
• Intermediate-modulus, type IM (modulus between 200-350GPa)
• Low modulus and high-tensile, type HT (modulus < 100Gpa, tensile strength >
3.0GPa)
• Super high-tensile, type SHT (tensile strength > 4.5GPa)

Based on precursor fiber materials –

• PAN-based carbon fibers
• Pitch-based carbon fibers
• Mesophase pitch-based carbon fibers
• Isotropic pitch-based carbon fibers
• Rayon-based carbon fibers
• Gas-phase-grown carbon fibers
Conti...

Based on final heat treatment temperature –

High-heat-treatment carbon fibers (HTT):

• Where final heat treatment temperature should be above 2000°C.

• Can be associated with high-modulus type fiber.

Intermediate-heat-treatment carbon fibers (IHT):

• Where final heat treatment temperature should be around or above 1500°C.

• Can be associated with high-strength type fiber.

Low-heat-treatment carbon fibers (LHT):

• Where final heat treatment temperatures not greater than 1000°C.

• These are low modulus and low strength materials.
 Carbon Fiber – Fabrication

 To melt C, we must put it under 10MPa and higher than 3800°C.

 Organic fiber with a high content of C is used as a precursor in manufacturing
carbon fiber under the protection atmosphere of N2 or Ar.
 Majority of non-carbon elements are removed by heating (carbonization).

Kinds of raw yarns of Carbon Fiber:-

1) Viscose fiber (regenerated cellulose) (C6H10O5)n –
• Needs the process of traction graphitization at high temperature.
• The technology is difficult, the equipment is complex, cost is high and carbonization
yield is low (20%∼40%).
• The retained is only part production for abrasion resistant material application.

2) Pitch fiber –
• Found in abundance.
• Carbonation yield is high (70%∼ 90%), and new technics are developing
unceasingly, with a very good prospect, especially in improving the fiber modulus.
3) PAN Carbon fiber (C3H3N)n-Fabrication
The manufacturing process of PAN carbon fiber includes three main steps:-
1) Thermo-oxidative stabilization in air at 180–400°C.
2) Carbonization in inert atmosphere at 600–1500°C.
3) Graphitization at 2000–2500°C in inert atmosphere.

• PAN fiber can be made into high-performance carbon fiber, with a high carbonization yield
(40%∼60%).
• The manufacturing method is simpler than other methods.
• The highest yield, the largest species, and the fastest development.

The production process of PAN based carbon fiber

 Applications of CFRP

CFRP IN AIRCRAFTS –
• Using 50% of the structural parts (aircraft wing), can reduce weight by about 20%.

CFRP IN AUTOMOTIVE INDUSTRY –

• If CFRP is used for 17% of an automobile's parts, its weight can be reduced by
about 30% of a standard automobile.

CFRP REDUCES CO2 EMISSIONS –

• CFRP can greatly reduce fuel consumption by making automobiles and aircraft
lighter. As a result, adoption of CFRP reduces CO2 emissions over the entire life
cycle of the product.

CFRP AS FRICTION BEARINGS –

• Excellent dry running characteristics.
• An ideal solution for use in pumps and in offshore and onshore facilities to reduce
maintenance and increase reliability.
• It can withstand up to 260°C.
Comparison between GFRP and CFRP on the basis of their Physical and Mechanical
Properties

Property GFRP CFRP

Tensile Strength (MPa) 480-1600 1500-3700

Yield Stress (MPa) 2750-2875 228×10^3
Modulus of Elasticity (GPa) 30-36 110-120
Shear Modulus (GPa) 3.89 5
Fracture Toughness (MPa·√m) 7-23 6.12-88
Elongation (%) 1.2-3.1 0.3-2.5
Density (g/cm3) 1.75-1.97 1.4-1.7
Hardness 306-612HV 10.8-21.5HV
Specific Gravity 1.87 1.6
Melting Point (°C) 1260 140-220
Electrical Resistivity (Ω.m) 10^15 1.8×10^−5
Thermal Conductivity (W/m.K) 1.2-1.35 1.28-2.6
Specific Heat (J/kg.K) 800-805 902-1037
 Aramid Fiber – Fabrication

 Polymer poly-metaphenylene isophthalamide is used to make meta-aramids.

 Polymer poly-phenylene terephthalamide to make para-aramids.
 Produced by wet and dry spinning methods.
 Sulphuric acid is the normal solvent used in the spinning processes.

 Methods of Fabrication:-

1) Wet spinning a strong solution of the polymer, which also contains inorganic salts,
is spun through a spinneret into weak acid or water.

2) Dry spinning process the salts are more difficult to remove and this process is only
used to produce the weaker meta-aramid fibers.
Process Flow of Kevlar Manufacturing
 Properties of Different Kevlar Fibers

Yarn Kevlar and

Kevlar 49 Kevlar 68 Kevlar 119 Kevlar 129 Kevlar 149
Properties Kevlar 29
Multipurpose High Moderate High High Ultra high
Characteristic
yarn Modulus Modulus Elongation Tenacity Modulus
Tensile
23 23 23 24 26.5 18
Strength gpd
Initial
550 950 780 430 750 1100
Modulus gpd
Elongation % 3.6 2.8 3 4.4 3.3 1.5
Density g/cc 1.44 1.45 1.44 1.44 1.45 1.47
Moisture
6 4.3 4.3 - - 1.5
Regain%
*grams per denier - the weight in grams of 9000 meters of yarn
 Applications of Aramid Fiber
of CFRP

• Flame resistance clothing, helmets

• Used in tyres for resisting wear and tear because of their high strength properties
• Used for making sporting goods
• Used in many civil structure, mechanical structure
• Ballistic protective applications such as bullet proof vests
• Protective apparel such as gloves, motorcycle protective clothing
• Sails for sailboats, yachts etc.
• Belts and hosing for industrial and automotive applications
• Aircraft body parts
• Boat hulls
• Fiber optic and electromechanical cables
• Friction linings such as clutch plates and brake pads
• Gaskets for high temperature and pressure applications
 Comparison between Glass, Aramid, And Carbon Fiber

On the basis of Physical and Mechanical Properties:-

Unit Glass Fiber Aramid Carbon Fiber

Property
E S Fiber HS HM
Density g/cm² 2.54 2.46 1.45 1.76 1.8
Tensile Modulus GPa 72 87 124 235 338
Tensile Strength MPa 3400 4600 3600 3500 2480
Specific Modulus GPa/g/cm³ 28 35 85 133 188
Specific Strength MPa/g/cm³ 1340 1870 2480 1990 1380
Elongation at Break % 4.8 5.4 2 1.2 0.5

Coefficient of thermal Expansion 10-⁶m/mK 5 2.4 -3.5 -0.36 -0.54

Graphical Representation of Stress-Strain for Different Materials
 Resins
Resins can be divided into two broad classes: thermosetting and thermoplastic.

Thermoplastic:
• Have a definite melting point
• They soften, but they do not liquefy

Thermosetting:
• Cure to produce an infusible solid material that does not melt when heated with
chemical additives

These resin families have unique usefulness depending upon the specific corrosive
process, temperature, and engineering requirements of the application.
Properties of resins :-

According to the type of resin used, FRP pipes can be classified as:

GRP-
 Fiber glass reinforcements which are set in cured thermosetting resin.
 For both restrained and non-restrained underground applications.
 In media temperature upto 600C.
GRV-
 Using Vinyl ester Resin throughout.
 For Industrial applications where specific chemical resistance is required.
 Used mainly in above ground applications
 In media temperature upto 850C.
GRE-
 Using Epoxy Resin throughout.
 In media temperature upto 1200C.
 Types of Thermoset Resins Used In Corrosion Applications

Unsaturated Isophthalic Polyester Resins-

•Is a blend of styrene and the condensation product with a mixture of maleic anhydride
(MA) and isophthalic acid.
•Used in the production of FRP’s and filled plastic products, including tanks, pipes,
gratings, and high performance components for the marine and transportation industry.

Terephthalic Polyester Resins-

•Terephthalic acid based resin, with medium to low reactivity and min. viscosity.
•Recommended for acid resistance applications below 50°C.
•Used in pipe manufacturing, storage tanks & vessels, lining of tanks, ducting etc.
 Vinyl Polyester Resins-
• Produced by the esterification of an epoxy resin with acrylic or methacrylic acids.
• Extensively used to manufacture FRP tanks and vessel and in marine applications.

 Chlorendic Polyester Resins-

• Chlorendic anhydride and chlorendic acid are used in manufacturing of these resins.
• Fire resistant and they often exhibit a significant degree of UV stability.

 Bisphenol A Fumarate Resins-

• Powdered, monomer-free, bisphenol-A fumarate polyester.
• Used as a styrene soluble binder for fiberglass reinforcement products.

 Epoxy Novolac Vinyl Ester-

• Combination of both polyester resin and epoxy resins.
• Medium viscous, medium reactive.
 Bisphenol Epoxy Vinyl Ester Resins-
• Produced by the addition of α - β unsaturated carboxylic acids to epoxy resins.
• A medium viscosity , tough and flexible vinyl ester resin.
• Provides resistance to a wide range of alkalis, bleaches, and organic compounds for
use in many chemical processing industry.

 Urethane-modified Vinyl Ester Resins-

• Prepared by copolymerization of an epoxy resin and a urethane oligomer.
• Ideal for filament winding.
• Creates a tough, resilient polymer.

 Furfural Alcohol Resins-

• Produced by self polycondensation of furfuryl alcohol monomer which reacts with
the active a-hydrogen of another furfuryl alcohol molecule.
Types of Resins used in fabrication of FRP’s:-

Resin Type Key Attributes

Unsaturated Polyester Low material cost, low molding cost, room temperature cure, good
(UPR) mechanical performance, and best cost vs. performance.

Modified Acrylic Low molding costs, room temperature cure, good mechanical
properties with high filler loading, low flame spread and smoke
generation.
Epoxy Vinyl Ester Higher material cost vs. UPR, low molding cost (similar to UPR),
(EVER) excellent corrosion resistance, improved mechanical properties and
heat resistance compared to UPR.
Epoxy Higher material and molding cost than EVER, excellent overall
mechanical properties, high toughness.
Phenolic Similar cost to UPRs, lower mechanical properties vs. UPRs, excellent
flame retardancy without additives, high heat and solvent resistance.

Polyurethane Similar material cost as epoxy resins, similar molding cost compared
to EVERs, excellent mechanical properties, high toughness, and high
adhesion to reinforcements.
Polyethylene A thermoplastic polymer with mechanical properties higher than Vinyl
Terephthalate (PET) Esters’ but slightly lower than epoxy’s. Excellent impact resistance
and toughness properties with excellent adhesion to reinforcements.
Catalyst (Initiator)
• Used to transform low viscosity polyester resin to high
viscosity solid.
• Dimethyl aniline (DMA) is used to activate peroxide
catalyst.
• Promoters such as, Cobalt Naphthenate is used to increase
rate of cure.
• Generally used are Methylethylketone peroxide (MEKP),
benzoyl peroxide (BPO) and cumene hydro-peroxide
(CHP).
Methylethylketone Peroxide (MEKP)
• Excellent curing performance.
• Activated by DMA and rate of curing is increased by cobalt
naphthenate and cobalt octoate.
• Gel Time: Time lapse between the addition of catalyst and point at
which resin becomes gelatinous.
• Addition of 0.1% of DMA will speed gel and cure rate.
• Must always be added as the last component.
• Levels of addition:
• Cobalt Naphthenate 0.3-1.0 phr* (%)
• DMA 0.1-0.3 phr (%)
• MEKP 1.0-1.5 phr (%)
• Grades that greatly reduce foaming are DION9100, DION9420 and
DION9800-05A.
*per hundred parts of resin by weight
Cumene Hydroperoxide (CHP)

• Eliminate foaming in vinyl ester resins.

• Used to eliminate exotherm problems in thick laminates.
• When used in substitution for MEKP, results in slower release of heat.

Benzoyl Peroxide (BPO)

• Activated by DMA and provides very fast gelation and cure.

• Difficult to evenly disperse in resin than MEKP.
• Improperly dispersed BPO may lead to permanent undercure.
Flame-Retardant Resins

• Cure well with MEKP catalyst systems.

• Antimony trioxide is added to optimize flame retardance but can be difficult to disperse.
• Pre-dispersed form e.g. Nyacol, APE 3040.

Inhibitor
• Tert-butyl catechol (TBC-10) can be used to extend gel time.
• 2,5 ditert-butyl hydroquinone are used to lengthen gel time and reduce exotherm
development.

Accelerators (Promoters)
• Dimethylaniline (DMA) is used to speed up the curing reaction of polyester and vinyl ester
resins.
• Usually 0.05-0.6% of DMA promoter is added.
• Should be thoroughly mixed with resin before adding the catalyst.

*Fabrication should not be attempted below 40◦F.

Other Additives:-

Pigments & Colorants:

• To enhance weatherability.
• For gel coats, finely milled pigments are blended with resin.
• Pigments may slow down or speed up resin gel time.

Suppressants:
• Styrene emission suppressants are used to block evaporation for air quality
compliance.
• These wax-based materials form a film on the resin surface and reduce styrene
emissions during curing.

UV Inhibitors & Stabilizers:

• Added to prevent loss of gloss, crazing, chalking, discoloration, changes in
electrical characteristics, embrittlement and disintegration.
• The addition of a UV stabilizer will slow the surface degradation of a non-gel
coated resin.
Conductive Additives:

• To obtain a degree of electrical conductivity by the addition of metal or conductive

fibers like carbon particles, carbon fibers, SS fibers, Ni coated graphite,
PermaStat®, PermaStat PLUS®.
• Electromagnetic interference shielding can be achieved by incorporating conductive
materials.

Release Agents:

• Facilitate removal of parts from molds.

• These products can be added to the resin, applied to molds, or both.
• Zinc stearate is a popular mold release agent that is mixed into resin for
compression molding.
• Waxes, silicones and other release agents may be applied directly to the surface of
molds.
Additives:-

Filler Amount Purpose

Thixotropes (Fumed 1-2phr* Viscosity control - Prevent resin from flowing out of the
silica) reinforcement before cure
Antimony trioxide 1-5phr Fire retardant synergist - Added to halogenated resins at 1.5% to
5% by wt. (effective snuffing compound)
Antimony pentoxide 3-5phr Fire retardant synergist - Added to halogenated resins at 1.5% to
5% by wt. (effective snuffing compound)

Aluminum trihydrate 50-120phr Low smoke formulation - Can be added at a max. percentage of
200% by wt.
Carbon black/graphite 1-30phr Electrical conductivity - Usually added 5-10 wt.%

Silica carbide 1-30phr Abrasion resistance

Pigments/UV stabilizer 1-2phr Cosmetics/UV protection – to enhance weatherability
* parts per hundred parts resin
Effect of Silicon Dioxide (SiO2) On Physical and Mechanical Properties
of Vinyl Ester Composite

 The filler material used in this study is silicon dioxide (SiO2) with different wt.%
i.e. 0wt%, 5wt%, 10wt%, 20wt% and 30wt %.

 Composite Fabrication-

• Two layers of aramid fiber is cut into 250*250 mm was used for specimen.
• Hardener is mixed in the ratio of 20:1 and silicon dioxide is added in different
percentage ranges.
• Acetone is sprayed on the inner side of mold before pouring the mixture.
• A layer of aramid fiber again poured, repeating the procedure till two layers of
aramid fiber in between three layers of the mixture is obtained.
• After the mold is completely dried, the composite material was taken out.
 Conclusion:-
• Tensile strength increases from 0.02 KN/mm2 to 0.06 KN/mm2 by adding SiO2 content from
0 to 20 wt. % .whereas further increases in SiO2 content i.e. 30 % results in decreases the
value up to 0.04 KN/mm2.
• Flexural strength increases from 0.01 KN/mm2 to 0.013 KN/mm2 by adding SiO2 content
from 0 to 20 wt. % .whereas further increases in SiO2 content results in decrease in the value
of flexural strength.
• The value of hardness and percentage elongation also shows the same trends as in the case of
tensile and flexural strength.
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