2. Dr. SURENDRAN PARAMBADATH
(M.Sc, M.Phil, M.Tech)
Formerly: Post Doctoral Research Associate,
Nano-Information Materials Research Laboratory,
Pusan National University, Busan-South Korea
Currently: Assistant Professor
Govt. Polytechnic College, Perinthalmanna

3. What is a polymer?
• A long molecule made up
from lots of small molecule
called monomers.

4. Poly = many, Mer = unit
Macromolecules: If the compound containing hundreds or
thousands of atoms per molecule are called macromecules.
Eg: Starch, Cellulose, proteins, nucleic acids, rubber, silk etc.
The repeating unit in the molecule is called monomer.
Polymers consisting of a single type of monomer molecules are
known as homopolymers.
The polymers obtained from monomers of different types are
called copolymers.

6. Homopolymer
-A-A-A-A-A-A-A-A-
Example: Polythene, nylone-6, Polystyrene, Polyvinyl chloride
(PVC)
Formation of homopolymer………………

7. Copolymer
-A-B-A-B-A-B-A-B-A-B-
Example: Nylone-6.6, Styrene-butadiene rubber (SBR), Buna-S,
Bakelite.
Formation of Copolymer…………………

8. POLYMERIZATION
It is the process of chemical combination of two or more
smaller and simpler molecules of similar or different types,
with or without the elimination of small molecules like H2O,
HCl or C2H5OH, resulting in the formation of new C-C or C-N
linkages in the product.
Example:
Polythene from ethene
Nylone-6 from caprolactum
Buna-S from Butadiene and styrene
Nylone-6,6 from Hexamethylene diamine and adipic acid with elimination
of H2O.

9. Polymerization is of two types
1. Addition polymerization
2. Condensation polymerization

10. 1. Addition polymerization
In this type of polymerization, the polymer formed in an exact
multiple of monomer molecules and there is no elimination.
This polymerization may initiate by heat or pressure.
nCH2=CH2 -(-CH2-CH2-)-
Ethylene Polyethylene

11. 2. Condensation polymerization
In this type of polymerization, chain growth takes place together with
elimination of small molecules like water, ammonia, alcohol etc.
This polymerization may initiate by heat or pressure.
HO-CH2-CH2-OH + HOOC-C6H4-COOH
Ethylene Glycole 1,4-dibenzoic acid
-H2O
-{-O-CH2-CH2O-CO-C6H4-CO-}-

13. No Addition Polymerization Condensation Polymerization
1 Formed by the simple addition In this process two or more
of monomers with out liberation monomers will combine together
of small molecules. with the liberation of some simple
molecules.
2 Monomers usually contains Monomers contain two functional
double or triple bond groups.
3 The monomers and polymers The monomers and polymers
having the same empirical having the different empirical
formula. formula.
4 Most of them asre formed by Most of them are formed by step
chain growth polymerization. growth polymerization.

15. 1 Based upon Natural and synthetic polymers
source
2 Based upon Addition and condensation polymers
synthesis
3 Based upon Inorganic and organic polymers
elements
4 Based upon Plastic: Intermolecular forces of attraction are
molecular intermediate between those of elastomers and
forces. fibers.
Elastomers: Chains are held together by weak
forces
Fibers: Held together by strong inter molecular
forces.

16. Elastomer
Fibre
Plastic

18. A plastic is a material which shows the
property of plasticity ie, capacity to change to
different forms under pressure.
Plastics may be defined as organic material of
high molecular mass, which can be moulded
into any desired shape, by subjecting to
suitable heat and pressure conditions in
presence of a catalysts.

19. • No cross links between chains.
• Weak attractive forces between chains broken by
warming.
• Change shape - can be remoulded.
• Weak forces reform in new shape when cold.

20. • Extensive cross-linking formed by covalent bonds.
• Bonds prevent chains moving relative to each
other.

21. Thermoplastics Thermosetting Plastic
1 They have formed by addition They have formed by condensation
polymerization and usually have polymerization and usually have three
linear structure dimensional extensive cross linking
between the polymer chains.
2 They are soft, weak and less They are more hard, strong brittle and
brittle and are soluble in organic insoluble in organic solvents.
solvents
3 Can be remoulded, recast Cannot be remoulded or reshaped.
reshaped, and reused by Once set, it cannot be recast by any
application of suitable pressure means.
and temperature.
4 On heating they soften and On heating, do not soften, rather they
become fluid but on cooling become hard and infusible, prolonged
become hard. heating make them burn.
5 Eg. Cellulose acetate, PVC, Bakelite, polyester, terylene, resins,
Polythene, Polypropylene, Teflon urea-formaldehyde polymer ect.
etc.

23. 1 Light weight, but tough very good tensile strength, high dimensional
stability and high refractive index.
2 Low thermal and electrical conductance and high insulating power, low
thermal expansion-coefficient, very good shock absorption capacity.
3 Resistance to corrosion and rust, to abrasion, to growth of fungus and
insects, action of fumes, gases and corrosive substances.
4 Chemical inertness to acids, oils, dampness, light etc.
5 Capability of being made (a) hard or soft (b) rigid or pliable © tough or
fragile (d) opaque or transparent (e) brittle or malleable or elastic (f)
wearable, curvable or pourable.
6 Easy workability, ability to take variety of fast and appealing colors,
shades. Shining glossy appearance etc.
7 Low fabrication cost and low maintenance cost.

24. 1.Higher cost and combustibility
2.Poor ductility
3.Softness and deformation under load
4.Brittleness at low temperature
5.Low heat resistance
6.Non biodegradable
7.Not easy to dispose off.

26. Elastomers include all those polymers, whose chains are held
together by weak forces and hence can be stretched by pulling
and on relieving the stress, can be made to regain their original
shape.
Eg: Rubber

27. Natural Rubber
Destructive, distillation of rubber from the tree gives a
hydrocarbon C5H8 isoprene-(2-methyl-1,3-butadiene) which is
the repeating unit in rubber. Rubber contains 16000-20000 units
in one string.

28. Vulcanization
It is the process of heating natural rubber with sulphur (3-5%),
H2S, benzoyl chloride to a temperature range 110-140oC.
Merits of Vulcanization
1. It helps in preventing the slippage of chains on application of
stress.
2. It makes rubber less sensitive to temperature changes.
3. It increases elasticity, tensile strength and extensibility.
4. It increases the resistance of rubber to oxidation, abrasion, wear
and tear, water and organic solvents.
5. Rubber becomes a better electrical insulator as a result of
vulcanization

29. Applications of Rubber
1. For making rubber bands, golf balls, mechanical
rubber goods, rubber gaskets for sealing equipments
like pressure cooker, refrigerators doors etc.
2. For making automobile and aeroplane tyres due to its
abrasion resistance.
3. In telephone receivers, battery cases, electrical
switch board panels etc.
4. Due to its remarkable resistance to electricity used
for insulating coating on wires and cables.
5. In medicine, rubber is used for making heart valves,
transfusion tubings, padding for plastic surgery etc.
6. It finds uses as an eraser and adhesive too.

30. Synthetic Rubber
These are man made, rubber like polymer………………
Eg: Buna-S, Thiokol, Buna-N
Name Uses
1 Buna-S Manufacture of motor tyres, floor tiles, gaskets, wire & cable
insulation.
2 Buna-N Conveyer belts, high altitude air craft components, hoses
printing rollers, automobile parts.
3 Neoprene Wire insulations, cable covering for conveyer belts and chemical
apparatus, sponges etc.
4 Butyl Rubber Cycle and automobiles parts, tank linings
5 Thiokol Hoses, gaskets and covering for cables.
6 Silicon rubber Artificial heart valves, transfusion tubes and padding for plastic
surgery, in lubricants, paints and protective coatings, shoes.

32. Fibres are thread like bits of materials characterized by
great tensile strength in the direction of the fibre.
Cloths are making from fibres.
Types of Fibre……………..
1. Natural fibre, obtained from natural sources like cotton,
jute, wool and silk.
2. Semi synthetic fibres, obtained from natural sources eg:
cellulose, which is heated with special reagents to bring it
to solution or dispersed state and then turned into
filaments
Eg: Rayons.
3. Synthetic fibres, obtained by addition or condensation
polymerization.
Eg: Nylon, terylene, orlon etc.

34. A fibre may be defined as a
flexible macroscopically
homo-
geneous body of high tensile
strength, possessing a high
ratio of length to thickness
and a small cross section.

35. The main characteristics of a fibre forming polymer are,
1 Should be convertible to a dissolved form
and then spun into fine fabric.
2 Should posses high tensile strength to
produce stable fibre.
3 Should have sufficient resistance to light,
heat and air-oxidation.
4 Should be able to take fast colours.

37. Nylon 6,6
It is formed by the condensation polymerisation of adipic acid
and hexamethylene diamine.
It is a polyamide polymer.
n HOOC-(CH2)4- + n H2N-(CH2)6-NH2
COOH Adipic acid Hexamethylene diamine
O
-[-OC-(CH-C-NH-(CH6-NH-
2)4 2) + n H2O
]n-
Nulon-6,6 is stronger than natural fibres. They are elastic, light
weight, very strong and flexible, inert to chemicals and biological
agents and are used in making fabrics, carpets, tyre cords, ropes etc.

39. Nylon 6
It is manufactured by prolonged heating of caprolactum at 260-
270oC.
It is another polyamide polymer.
H
N
O
CH2 C=O
260-270oC
-[
-C-NH-(CH5-]n-
2)
CH2 CH2
C C
H2 H2
Caprolactum Nylon 6

41. Terylene or Dacron
Condensation polymerization of terephthalic acid
and ethylene glycol, in presence of a weak base
results in the formation of the most important
polyester fabric named Terylene.
HOOC COOH + OH-CH2-CH2-OH
Teraphthalic acid Ethylene Glycol
-[-OC-C6H4-CO-O-CH2-CH2-O-]n-

43. Orlon
Polymerization of acrilonitrile (vinylcyanide) in
presence of FeSO4 and H2O2, gives orlon.
It is water resistant quick drying, can be woven or
knitted, can be blend with wool, used in making
cloths, carpets, blankets etc.
Polymerization
n CH2=CHCN -[CH2-CH-]-
Fe2SO4/H2O2
CN

46. Composites are reinforced plastics.
Composites consists of two components,
1. Matrix phase and
2. Dispersed phase

48. 1. Matrix Phase
Matrix phase is the main part of the composite.
Metal can give metal matrix composite,
Ceramics can give ceramic matrix composite,
Polymer can give polymer matrix composite.
Matrix should satisfy the following criteria,
1. It should be ductile
2. The bounding between the matrix and the filler should be
strong.
3. The fibre and matrix should be chemically compatible with
each other.

49. 2. Dispersed phase
The reinforcing material should be strong and
stiffer than the matrix to increase the strength of
the matrix.
Wood floor, Asbestos, Clay, marble powder, mica, graphite, fibres
of glass, cotton, carbon or ceramic may be used as dispersed
phase.
Metallic oxides like ZnO, PbO or powders of metals like Si, Cu, or Pb
are also used.

55. On the basis of the structures of the reinforcing
material, the composites are classified as,
1. Fibre reinforced composite: In this type of
composite, fibers are embedded in a suitable
matrix.
2. Particulate composite: These contain
particles of a wide range of size dispersed in a
matrix.
3. Dispersion hardened composite: These
contain very fine particles dispersed in a
matrix.

59. Fibre reinforced composite

62. Glass Reinforced Plastics (GRP)
GRP are the most common example of fibre reinforced
plastic. In this plastic acts as the matrix glass fibre as the
dispersed phase.
These have low density, high tensile strenghth, resistance to
thermal and chemical corrosion.
GRP finds use in
1. Plastic pipes
2. Storage tanks
3. Speed boats
4. Flooring materials
5. Automobile parts
6. Battery boxes.