Speciality Polymers

Rubbers also known as elastomers are linear
polymers which exhibit elastic property distinctly.

 Collection of latex
 Processing of latex
 Coagulum
 Crepe rubber
 Smoked rubber
 Mastication

 Collection of latex:
Hevea brasiliensis
(30-60 % rubber)

 Processing of latex:
Coagulum
Latex is filtered to remove any dirt present in it. This latex is then
coagulated by using 1% acetic acid/formic acid solution.
A soft white mass is obtained called as coagulum.

 Processing of latex
 Crepe rubber
Coagulated rubber is drained for about 2 hrs. and then passed
through creping machine to obtain pale yellow crepe rubber.

 Smoked rubber
 Latex is coagulated long times having vertical groves where
metal plates are fitted.
 Metal plates with groves are inserted in the tank after
coagulation.
 The tank is kept undisturbed for about 16 hrs.
 The tough slabs of rubber are obtained and passed through a
series of smooth rollers to get ribbon like pattern of thin rubber
sheet.
 These thin sheets are then hanged in smoke house for 4 days at
40-50oC.
 The rubber so formed called as Smoked rubber.

 Masticated rubber
 Crude rubber is masticated and compounded with chemicals
such as sulphur (vulcanization), accelerators & antioxidants and
then converted into utility articles by suitable processing.
 Mastication is the process of making rubber soft & gummy by
subjecting it to several mechanical working.
 During mastication, rubber is broken down into small particles
by passing it through roller mill.
 Mastication causes decrease in molecular weight of rubber due
to oxidative degradation.

 Natural Rubber is a polymer of Isoprene. To understand
the structure of Rubber we shall concentrate on structure
of Isoprene. Isoprene is a conjugated diene containing
double bonds at alternate position.
 Structure of Isoprene: Monomer of Natural Rubber

 Polymerization of Isoprene may follow either of the two
pathways; either of cis-polymerization or trans-
polymerization. The rubber formed from cis-
polymerization is called cis-polyisoprene or Natural
Rubber. Similarly, the rubber formed from trans-
polymerization is called Synthetic Rubber.

 It becomes soft at high temperature and too brittle at low
temperature. Thus, it can be used in the range of 10 to
60oC only.
 It is weak & its tensile strength is 200 kg/cm3.
 It has large absorption capacity.
 It can be attacked by non polar solvents like vegetables
and mineral oils, gasoline, benzene & carbon
tetrachloride, etc
 It perishes, due to oxidation in air.

 It swells & gradually disintegrates in organic solvents.
 It possesses remarkable tackiness i.e. when two fresh raw
rubber surfaces are pressed together, they coalesce to
form a single piece.
 When stretched to high extent, it suffers permanent
deformation.

Vulcanization of
Natural Rubber

The process of compounding raw rubber with some chemicals
(vulcanizing agents) like sulphur, hydrogen sulphide , benzoyl peroxide etc to
improve the properties of rubber is called as vulcanization.

 Natural rubber
 Useful temp range is 10 to 60
oC
 Low tensile strength(200
kg/cm2)
 High water absorption capacity
 High tackiness
 Low resistance to oxidation in
air
 Vulcanized Rubber
 -40 to 100o C
 High tensile strength(2000
kg/cm2)
 Low water absorption capacity
 Low tackiness
 High resistance to oxidation in
air

Styrene - Butadiene rubber (SBR)
Government Styrene rubber
Ameripol
Buna - S

 It is prepared by copolymerization of 75% butadiene &
25% styrene by weight.
 Cumene hydroperoxide is used as catalyst for
polymerization.
 It is a block copolymer, prepared by emulsion
polymerization.

nx CH2 CH CH CH2 + ny CHCH2
Copolymerization
CH2 CH CH CH2 CHCH2 AA
n

 It possesses high abrasion resistance.
 It has load bearing capacity and resilience.
 It shows high resistance to heat.
 It swells in oils and solvents.
 It get readily oxidized by traces of ozone.
 It can be vulcanized by sulphur.

 Mainly used for making motor tires because of high
abrasion resistance.
 It is used for floor tiles, shoe soles, gaskets, electrical
insulation, adhesives, carpet backing, conveyer belt etc.

Speciality
Polymers
Thermoplastic
Polymers
Biodegradable
Polymers
Conducting
PolymersElectroluminescent
Polymers
Liquid Crystal
Polymers
Polymer
Composites

Engineering thermoplastics are group of materials obtained
from high polymer resins which provide one or more outstanding
properties when compared with the commodity thermoplastics
such as polystyrene, polyethylene, polypropylene, etc

Advantages of Engineering Thermoplastics include,
1.High thermal stability.
2.Excellent chemical resistance.
3.High tensile & impact strength.
4.High flexibility.
5.High mechanical strength.
6.Light in weight.
7.Readily mouldable into complicated shaped.
8.High dimensional stability.

Thermoplastic Polymers
Polycarbonate (Lexan or Merlon)
O C
CH3
CH3
O C
O
AA
n
It can be obtained by interaction of Bisphenol-A with diphenyl carbonate.

O C O
O
C
C C
C
CC
C
C
C
C
C C
C
CC
H H
H H H
H H
H
H H
H
H
H H
( )n

Thermoplastic Polymers: Polycarbonate (PC)
Physical Properties:
1. High impact strength & tensile strength over wide range of temperature.
2. Highly transparent plastic (higher light transmittance: 88%).
3. It is resistance to water & many organic compounds, but soluble in number of
organic solvents & alkalis.
4. It has a good resistance (up to 140oC), thermal stability, oxidative stability and
high melting point (265oC).
It has a tendency to yellow with long term ultra violate exposure
It has good thermal & oxidative stability

Applications:
1. Electrical and Electronic components
Being good insulator, having heat resistant and flame resistant
properties, it is used in various products associated with electrical &
telecommunication hardware.
They can be used for making electrical insulators, industrial plugs,
sockets, switches, covers of cell phones, laptops, papers, etc
2. Data Storage
The production of CD, DVD’s, and Blue ray Disc by injection moulding
of polycarbonate.

Applications:
3. Optical applications
It is used for (ultra-light) Sunglasses, Swimming & SCUBA glasses, safety
glasses, visors in helmets, automotive head lamp lenses as it has high optical
clarity.
It is also used for widescreens for motorcycles, golf carts, small planes
& helicopters.
It can also be used for electronic display for use In mobile and portable
device for some LCD screens.

Applications:
4. Security components
It can be laminated to make bullet-proof glass.
5. Other applications
It is used as housing for machinery / apparatus such as hair drier
bodies, camera & binocular bodies.
It is used as transparent food containers, cooking utensils covers,
blender jars, drinking bottles, glasses, toys, etc

Biodegradable Polymer:
Definition:
Biodegradation of polymer is a process carried out by
biological systems (usually bacteria or fungi) where in polymer chain
is cleaved via enzymatic activity.

Biodegradable Polymer: Factors Responsible
1.Micro-organism
• Naturally occurring micro-organisms such as
bacteria, fungi & algae are responsible for
biodegradation of polymers by breaking C-C bond. The
process takes place at very slow rate.
• For the survival, action of micro-organisms & for
biodegradation process to function, suitable conditions
like temperature, moisture, pH, oxygen, salts
(concentration & type), pressure, light, etc are
important.
• Polymer should have ability to biodegrade itself. So it
needs such functional groups like amines, carboxylic
that they absorb water, swell & degrade.
2. Environment
3. Nature of
Polymer

Biodegradable Polymer: Features
1. Naturally occurring polymers are biodegradable.
2. Synthetic addition polymers with only carbon atom main chain
are not biodegradable at molecular weight above 500.
3. If polymer chain contains atom other than carbon in backbone it
may biodegrade depending on attached functional groups.
4. Synthetic polycondensation polymers are generally
biodegradable to extent depending on functional groups involved
( ester > ether > amide ).

Biodegradable Polymer: Features
5. Amorphous polymers are more susceptible for biodegradation
compared to crystalline polymers.
6. Generally lower molecular weight polymers undergo
biodegradation easily compared to high molecular weight
polymers.
7. Hydrophilic polymers degrade faster than hydrophobic polymers.

Biodegradable Polymers
1. Natural
Biopolymers
e.g.
Cellulose, Starch, P
rotein
2. Biosynthetic Polymers
e.g. Polyhydroxyalkanoates
(Polyhydroxyvalarate, Polyh
ydroxybutarate, etc)
3. Synthetic
Biopolymers
e.g.
Polycaprolactone, Polyl
actic acid, etc

Biodegradable Polymers: Applications
1. As Packing Material: It can be used in food packing, foam for
industrial packaging, film rapping, disposable plastic packing
material such as single serve cups, disposable food service
items, etc.
2. Medical Applications: Polymers like HB-HV, Polylactic acids are
used in controlled drug delivery because of biocompatibility &
biodegradability.
Cell transplantation using biodegradable polymers scaffolds
offers possibility to create completely natural new tissues &
replace organ function.

Biodegradable Polymers: Applications
3. Agricultural Applications: These polymers are used as time
release coating for fertilizers & pesticides, making films for
moisture & heat retention.

Biodegradable
Polymers
Polyhydroxybutarate (PHB)
Polyhydroxyvalarate (PHV)
Polyhydroxybutarate-hydroxyvalarate
[PHB-HV / PHBV / Biopol]

O CH
CH3
A CH2 C
O
A
n
It is produced by the fermentation of glucose by the
bacterium Alcaligenes eutrophus

O CH
CH2
A CH2 C
O
A
CH3
n
It can be produced by fermentation of glucose A. eutrophus /
P. oleovorans

O CH
CH3
A CH2 C
O
O CH
CH3
CH2 C
O
A
n
It can be produced by A. eutophus when grown in the
presence of glucose & either propanoic or valeric acid

Biodegradable Polymers: PHBV
Physical Properties: The physical properties of biopol
copolymer vary with hydroxyvalarate content of polymer.
1. As HV content increases in the range of 0.2 %, polymer flexibility,
toughness, tensile strength, resistance.
2. Melting point reaches minimum at about 30 % mole
hydroxyvalarate.
3. It is susceptible to hydrolysis above pH 9 and below pH 3, it can
be dissolved in number of chlorinated solvents like chloroform &
methylene chloride.

Biodegradation of PHBV:
PHBV shows complete biodegradation in both aerobic &
anaerobic conditions.
Apart from small amounts of biological material, the final
product of biodegradation are C02 & water for aerobic condition.
The final product of biodegradation are methane & some
C02 for anaerobic condition.
The rate of degradation depends on moisture, nutrients
supply, temperature, pH, etc

Biodegradable Polymers: Applications of PHBV
1. Medical Applications:
PHBV are used for controlled drug delivery as they
are biocompatible & biodegradable. Also it is non-toxic.
2. Disposable Personal Hygiene:
PHBV can be used as a sole structural material or as a
part of degradable composites.
3. Packaging:
PHBV can be used for films, blow moulded bottles &
as a coating on paper.

Conducting Polymer:
Definition:
Those polymers which has ability to conduct heat
better than that of metals, are called as Conducting
Polymers.

 Polymers become conducting upon doping
 Polymer becomes electronically charged
 Polymer chains generate charge carriers
 Concentration of dopant causes certain electrons to become
unpaired
 Formation of polarons and bipolarons
 They have extended p-orbital system

Conducting Polymers: Classification
1. Intrinsically Conducting Polymers (ICP): Some polymers can
conduct electricity of their own because of their structural features. Such
polymers are known as ICP.
• These are linear have high planarity in structure & conjugation in
the polymer chain.
• e.g. Trans-
polyacetylene, Polyaniline, Polyparaphenylene, Polypyrrole, Polyt
hiophene, etc
• Conjugated Π electrons conducting polymers are used in polymer
light emitting diodes (PLED), photodiodes & in solar cells.

C
CC
C
C
C
C
CHA
A
H
H
H
H
H
H
H
n
Trans-polyacetylene

N
H
N
H
N
H
N
H
AA
n
Polypyrrole

2. Doped Conducting Polymers: ICP posses low conductivity, but their
conductivity can be improved by creating positive or negative charges on the
polymer chain by oxidation or reduction. This technique is called as Doping.
a. P-doping
• It includes doping of ICP with a
Lewis acid. Oxidation takes place &
positive charge is developed on
polymer chain increasing
conductivity.
• Lewis acids like I2, Br2, FeCl3, PF6,
AsF6 can be used as p-dopants.
• e.g. doping of FeCl3 in (C2H2)n to
form (C2H2)n
+ FeCl4
- + FeCl2. by
oxidation.
b. N-doping
• It includes doping of ICP with a
Lewis base. Reduction takes place
& negative charge is developed on
polymer chain increasing
conductivity.
• Lewis acids like lithium, sodium
metals, naphthyl amines can be
used as n-dopants.
• e.g. doping of Sodium in (C2H2)n to
form (C2H2)n
- Na+ by Reduction.

Doping in polyacetylene
• Amount of dopant used is significantly higher
• Doped polyacetylene is always in tans form
• Neutral polyacetylene can be doped in two ways
p type doping : oxidation with anions eg : ClO4(-)
n type doping : reduction with cations eg : Na(+)
- e
+ ClO4(-) + ClO4(-)
+ e
+ Na(+)
(-)
Na(+)

Doped Conducting Polymers
C2H2
n
+ FeCl 3
2
Oxidation
C2H2
n
+
FeCl 4
-
+ FeCl 2
P-doping
C2H2
n
+
Reduction
C2H2
n
-
Na Na
+
N-doping

a. Conducting element filled polymer
• Metallic fibres, metal oxides, or carbon black can be mixed in
the polymer during moulding process.
b. Blended conducting polymer
• It is obtained by blending conducting polymers with
conventional polymer, physically or chemically.
3. Extrinsically Conducting Polymers: These are
conducting polymers whose conductivity is achieved by adding
external ingredients to them.

4. Coordination Conducting Polymers:
It is a charge transfer complex containing polymer, obtained
by combining a metal atom with polydentate ligand.
So there is a formation of coordination bond between the
polymer and metal which allow the transfer of electrons easily.
This there is a conduction takes place as energy gap between
higher energy level and lower energy level decreases.

Conductivity in Conducting Polymers
Conjugated polymers like polyacetylene are organic
semiconductors. They have a band gap. Conducting polymers have
extended delocalized bonds that creates the band structure similar to
that of silicon, but with delocalized state.
When charge carrier are introduced into the conduction or
valence bands, the electrical conductivity increases dramatically.
Doping generates charge carriers which move in electric field.
+ve charges (holes) & -ve charges (electrons) move to opposite
electrodes. These movement of charge is responsible for electrical
conductivity.

Conductivity in conducting polymers
In general, conductivity increases with decreasing band gap between the
valence band & conduction band.
Conduction
band
Valence
band
Conduction
band
Valence
band
Conduction
band
Valence
band
Eg
Forbidden
Energy gap
n-type
P-type
Polaron on
localized band
Energy band structure Energy band structure
of Si
Energy band structure
of conducting polymer

Conducting Polymers: Applications
1. In rechargeable light weight batteries, doped conducting
polymers are used.
2. In electronic devices such as transistors, photodiodes & light
emitting diodes (LED).
3. In optical display devices.
4. In telecommunication system.
5. In antistatic coatings for clothing.
6. In solar cells.
7. In drug delivery system for human body.
8. In molecular wires & molecular switches.

Conducting Polymers: Limitations
Conjugated polymers have few large scale applications
because of high cost, problems in processing (due to their
insolubility, infusibility, brittleness) & long term instability.

Conducting Polymers: Polyacetylene
The polymer consist of a long chain carbon atoms with
alternating single & double bonds between them. Each carbon
posses one hydrogen atom. It can be in two forms: cis & trans
(shown below) form.
Trans – polyacetylene
(discovered by Prof. H. Shirkawa by using Ziegler- Natta catalyst)
A A
n

Conduction Mechanism in Polyacetylene:
1. An electrical conductive polymer is able to conduct electricity
because of the conjugated Π-bond system.
2. The conjugated double bonds permit easy electron mobility
throughout the molecule because the electrons are delocalized.
3. When the oxidative dopants such as I2 is added, it takes away an
electron from the Π-backbone of the polyacetylene chain & creates a
positive charge (hole) on one of the carbons. The other Π-electron
resides on the other carbon making a radical cation known as
polaron.

4.The lonely electron of the double bond from which electron was
removed, can move easily. As a consequence the double bond moves
along.
5.A bipolaron formed on further oxidation.
6.As the 2 electrons are removed, the chain will have 2 positive
charges (holes). The chain as a whole is neutral, but the holes are
mobile. When a potential is applied, they migrate from one carbon to
another & accounts for conductivity.

7.When a Π-bond is introduced, valence band (VB)& conduction
band (CB) are created. Before doping, there is sufficient energy gap
between VB & CB, so the electrons remain in VB & polymer acts as
an insulator.
8.Upon doping, polaron & solitons are formed which result in the
formation of new localized electronic states that fill the energy gap
between VB & CB.

9.When sufficient solitons are formed, a new mid-gap energy band is
created which overlaps the VB & CB allowing electrons to flow.
10. The charged solitons are thus responsible for making
polyacetylene a good conductor.

Conducting Polymers: Applications of Polyacetylene
1. Doped polyacetylene offer a particularly high electrical
conductivity therefore used as electric wiring or electrode
material in light weight rechargeable batteries.
2. Tri-iodide oxidized polyacetylene can be used as sensor to
measure glucose concentration.

Electroluminescent Polymer:
Definition:
Electroluminescence is a phenomenon in which a material
emits light in response to the passage of an electric current or
strong electric field.
These are the polymers which emit light in response to the
passage of an electric current or strong electric field.
They have potential applications in LED devices (Flat panel
display for PC, TV, mobiles) and color pixels in ink jet printing.

Polymer Light Emitting Diode (PLED)
1. Semiconducting polymers, with Π electron system such as PPV
(Polyphenylene-vinylene) exhibit electroluminescence. To generate
light with these materials, a thin film of semiconducting polymers is
sandwiched between two electrodes.
2. Indium Tin Oxide (ITO) is commonly used anode material. It is
transparent electrode material which is deposited on glass / plastic
substrate. Metals like Ca, Mg, Al are used for cathode.

Polymer Light Emitting Diode (PLED)
3.Electrons & holes are then injected from the cathode & anode
respectively into polymer. Driven by the electric field, the charge
carrier move through the polymer over certain distance &
recombination takes place. The recombination of these charge
carriers results in luminescence.

Highly oriented PPV can be obtained by soluble polymeric precursor.
A
A

Electroluminescent Polymers: PPV
Physical Properties: (Bright yellow-green fluorescence on application of
electric field)
1. It is diamagnetic in nature & has a very low thermal conductivity (10 – 13 S/
cm).
2. The electrical conductivity increases upon doping with iodine, ferric chloride,
alkali metals or acids. However the stability of these doped materials are
relatively low.
3. Alkoxy substituted PPV shows ease of oxidation & have much higher
conductivities. Large side chain substitution lowers the conductivity.
4. It is water soluble, but its precursors can be manipulated in aq. Solution.

Electroluminescence Polymers: Applications of PPV
1. It is capable of electroluminescence. Due to its stability,
processibility & electrical as well as optical properties, PPV is
used in organic light emitting diode (OLED).
2. Devices based on PPV an emissive layer, emit bright yellow-green
fluorescent light & derivatives of PPV are used when light of
different color is required.
3. It is also used as electron donating material in organic solar cells.

Liquid Crystal Phase:
Crystalline solids have sharp melting point. On heating, there
is a sharp transition from solid crystalline phase (anisotropic) to
liquid phase (isotropic).
However, certain crystalline solids do not show this sharp
transitions from solid to liquid on heating. Intermediate stage can be
identified called as liquid crystal phase or mesomorphic phase.

Liquid Crystal Polymer:
Solid phase
Mesomorphic or
liquid crystal
phase
Heat Liquid phase

Definition:
A polymer that under suitable conditions of temperature,
pressure & concentration, exist as liquid crystal is known as liquid
crystal polymer.
Polymers that form liquid crystal stage contain long, rigid units
or disc shaped molecular structure called as mesogens

Liquid Crystal Polymers: Classification
1. Thermotropic Liquid Crystal Polymers:
• The polymers which have tendency to align their polymers chains (mesogens)
over a large distance before their crystallization from the melt, is called as
thermotropic liquid crystal polymers.
• e.g. Vectra, Victex, Xyder, etc

Liquid Crystal Polymers: Classification
2. Lyotropic Liquid Crystal Polymers:
• The polymers which have tendency to align their polymers chains (mesogens)
over a large distance before their crystallization from the solution, is called as
thermotropic liquid crystal polymers.
• e.g. Kevlar

Liquid Crystal Polymer: Classification
1.Smectic LCP • Polymer chains maintain orientational order , but also
tend to align themselves in layers i.e. mesogens are
arranged in parallel & lateral order.
• The polymer chains are arranged in parallel order but
not in lateral order.
• This is a modified nematic phase in which mesogens
are oriented parallel to one another but their
directions vary from one layer to another.
2. Nematic LCP
3. Cholesteric LCP

1.Smectic LCP
2. Nematic LCP

3. Cholesteric LCP

When polymer exhibiting liquid crystalline properties are formed, they can
be constructed with the mesogens with three forms as:
Main Chain LCP
Mesogens

Side Chain LCP
Mesogens
Polymer chain

Combined Chain LCP
Mesogens
Polymer chain

Liquid Crystal Polymers: Properties
They have good thermal stability, high dimensional stability, easily
moulded, good electrical properties at high temperature, very low coefficient of
thermal expansion, high chemical & solvent resistance and high crystallinity (Tg &
Tm are high).
Liquid Crystal Polymers: Applications
In electronic & electrical equipments, data storage discs, fibre optic
cables, chemical appliances, encapsulation of IC engine, housing for light wave
conductors, aerospace applications, as filer for composite material, military
communication.

NH NH C
O
C
O
AA
n
The polymer has very high strength due to intermolecular hydrogen bond
formed between carbonyl group and NH group.

Liquid Crystal Polymers: Kevlar
Physical Properties:
1. It has outstanding high strength to weight ratio. It is 5 times stronger than
steel & 10 times stronger than aluminum on equal weight basis. It is light
weight polymer with high strength.
2. It is thermally stable (M. P. > 500oC).
3. It is very resistance to impact & abrasion damage.
4. The Kevlar fibers can absorb moisture, so they are more sensitive to
environment than glass or graphite composites.
5. Although tensile strength & modulus is high, compressive properties are
relatively poor.

Liquid Crystal Polymers: Applications of Kevlar
1. Kevlar is often combined with carbon fibers & embedded in epoxy resins to
form hybrid composite that have the ability to withstand catastrophic impact.
2. It can also be used in light weight boat hulls, high performance race cars.
3. It has outstanding high temperature resistance & high tensile strength,
therefore can be used for fire retardant fabric & tyre cord.
4. It can be used as cables for mooring lines, offshore drilling platforms, for
parachute lines, fishing lines, mountaineering ropes & pulley ropes.
5. It can be used in protective clothing & body armor.

Polymers Composites:
Definition:
Polymer composite is the material which is made up of
polymer matrix & reinforcing materials being put together with a
definite interface.

Polymers Composites: Constituents
1. Polymer matrix phase:
• It gives a continuous body constituent, surrounding the other phases & gives a
bulk form to the composite.
• These may be thermoplastics (like polyolefins, polyimides, vinylic polymer,
polyphenyles, etc) or thermosetting (like Epoxy resins, Phenolic resins,
Polyesters, etc)
• Following are the functions of matrix phase:
• It binds the dispersed phase/reinforcement together.
• It helps in distributing externally applied load to the reinforcement.
• It prevents the development of cracks due to plasticity & softness.
• It protects the reinforcement /dispersed phase from chemical action & keeps
them properly oriented under the action of load.

Polymers Composites: Constituents
2. Reinforcement Phase:
• They are structural constituents like fibres, sheets, particles which are
embedded in matrix phase and provide high strength, rigidity & enhance matrix
properties.
• Fibres: Long thin filaments of glass, carbon, aramides are added to
matrix to give high tensile strength, high stiffness & low density.
• Particulates: Small metallic or non-metallic particles can be added to the
polymer matrix to increase surface hardness, abrasion, resistance & strength.
They reduce shrinkage, friction & cost. Particles carry major portion of the load
applied.

Polymers Composites: Classification
1. Particle reinforced composites:
• These are composed of particles distributed or embedded in the matrix body.
Metallic or non-metallic particles can be added to polymer matrix to improve
mechanical strength.
• e.g. carbon black reinforced rubber show improvement in tensile strength,
toughness & abrasion resistance and are used in manufacturing automobile
tyres.

2. Fibre reinforced composites:
• These are composed of fibres embedded in the matrix material. These can be
further divided into three categories continuous aligned (a), discontinuous
aligned (b) & discontinuous randomly oriented fibre (c) composites.
a
b
c

3. Structural Composites:
• Laminar composites: A laminar composites are made up of lamellar sheets that
have high strength in particular direction such as in wood or in continuous
aligned reinforced plastics.
• Sandwich panels: Sandwich panels consists of two strong outer faces surfaces
by a layer of dense core. Face material is generally fibre reinforced plastic
whereas core material can be synthetic rubber, foamed polymer, etc. These type
of materials are normally used in aircraft wings, boat
hulls, roof, floors, walls, etc.

Polymers Composites: Properties
They have high thermal stability, high tensile strength, stiffness, chip &
easily fabricable, low thermal expansion, high impact, oxidative & abrasion
resistance.
Polymers Composites: Applications
•In automobile body & parts, turbine engines, pumps, valves, etc
•In fabrication of roofs & floors, furniture.
•In manufacturing sports goods like rackets, toys, musical instruments.
•In marine applications – shafts, hulls, propellers, etc
•In components of rockets, aircraft, helicopters, etc
•In electronic applications – communication antenna, electronic circuit boards.

Fibre Reinforced Plastics (FRP):
Definition:
FRP is a composite material made of a polymer matrix
reinforced with fibres.
The characteristic properties of FRP depends upon:
a) Nature, orientation & distribution of fibres
b) Nature of polymer matrix
c) Strength of interfacial bonds between fibre phase & polymer
matrix phase.

FRP: Classification
1. Glass FRP:
• They use glass fibres reinforced in polymer matrix containing
nylon, polyesters, etc. Glass fibres are obtained by forcing glass melt through
spinnerate (having small holes) and rapidly pulling & cooling to get fibres.
• Advantages: They show improved properties as:
• High tensile strength & impact resistance.
• Lower densities
• Excellent resistance to corrosion & chemicals.

1. Glass FRP:
• Limitations:
• As Polymer matrix flows at high temperature, they show applications in
limited temperature range.
• Since the material do not posses desired stiffness & rigidity, they cannot be
employed as structural components.
• Applications:
• They are used in automobile parts, storage tanks, industrial flooring, plastic
pipes, etc
• They are extensively used in automobiles to reduce vehicle weight & boost
fuel efficiency.

2. Carbon FRP:
• They use carbon fibres reinforced in polymer matrix like epoxy or polyester
resins. Carbon fibres are obtained by pyrolysis of cellulose / Acrylonitrile in an
inert atmosphere. It has much higher elasticity modulus than glass fibres &
show better resistance to temperature & corrosive chemicals. However, they are
short fibres & are more expensive.
• High elastic modulus.
• Low density.
• Excellent resistance to corrosion.
• High Temperature resistance.

2. Carbon FRP:
• Applications:
• They are used as structural components (like wings, body, stabilizers, etc) of
aircrafts & helicopters.
• They are used in making sports goods (rackets, archery, racing
bicycles, etc), laptops, fishing rods, musical instruments, etc

3. Aramid FRP:
• They use carbon fibres reinforced in polymer matrix like epoxy or polyester
resins. Carbon fibres are obtained by pyrolysis of cellulose / Acrylonitrile in an
inert atmosphere. It has much higher elasticity modulus than glass fibres &
show better resistance to temperature & corrosive chemicals. However, they are
short fibres & are more expensive.
• High elastic modulus.
• Low density.
• Excellent resistance to corrosion.
• High Temperature resistance.

3. Aramid FRP:
• They are divided into two types
• Short Fibres - reinforced composites: Short fibres give high surface area,
toughness, strength, heat stability, wear resistance & effective reinforcement.
• Applications: Used in automobile brakes & clutches.
• Long Fibres - reinforced composites: Aramid fibres are capable of absorbing
energy to show very high compressive strength & ductility.
• Applications: Used as structural & advanced engineering material for aircrafts &
helicopter parts, as protective clothes, etc

Speciality Polymers

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Andere mochten auch

Andere mochten auch (20)

Ähnlich wie Speciality Polymers

Ähnlich wie Speciality Polymers (20)

Mehr von Santosh Damkondwar

Mehr von Santosh Damkondwar (9)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Speciality Polymers