LDPE is formed from ethylene at a high pressure of 1500-3000 atmosphere at a temperature range of175-250oC in presence of some oxygen, peroxide, or azocompounds as initiators. LDPE has nearly 20–50 branches (both long and short branches) per 1000 linear carbon atoms in the chain molecules. The loss of molecular symmetry due to the high degree of branching results in a lower density range (0.915–0.94 g/cm3 ) and lower softening or melting temperature. LDPE dissolves in toluene at or above 60°C.HDPE is usually more resistant to chemicals than LDPE. HDPE is soluble in toluene at 900C. 2–5 short branches or side chains per 1000 carbon atoms in the main chain, thus having a higher density range (0.945–0.96) and high melting temperature (125–130°C) compared to LDPE. HDPE-The polymerization at a low temperature and pressure in presence of metal oxide catalyst Poly ethylenes are very good insulating materials and are adequately flexible hence used as an insulator in wires and cables. They find extensive uses and applications as molded or formed objects, films, sheets, bottles and containers, pipes, and tubes. Polythene finds application in packaging, waterproofing, irrigation, and water management including canal lining and mulching, and in coating and lamination. Polypropylene - Addition polymer Thermoplastic Monomer propylene USES For making household appliances In package industry For making plastic parts of machinery For making plastic furniture For making syringes, medical vials, Petri dishes, pill containers, specimen bottles. Polystyrene is synthesized by the polymerization of styrene at 335K in the presence of a benzoyl peroxide initiator. It is used as an electrical insulator. Expanded polystyrene finds extensive use in packaging and shock absorbing applications, in thermal insulation, and as acoustic improvers in halls and auditoria. High impact grades are suitable for use as toys, games and sports articles, casings and cabinets for electrical/ electronic gadgets and equipment, and inner liners of refrigerators. Another major use of polystyrene is in the making of ion-exchange resins. Kevlar is an aromatic polyamide Five times more tensile strength than steel. POLYVINYL PYROLIDONE(PVP)(POVIDONE),ETHYLENE VINYL ACETATE (EVA), SARAN , TEFLON (polytetrafluoroethylene) – A fluoro polymer, POLYACRYLONITRILE (PAN),Poly(Methyl Methacrylate) (PMMA), Poly(Hexamethylene Adipamide): Nylon 66, Nylon 6, KEVLAR, Terylene, GLYPTAL, Lexan, POLYURETHANES, UF( Urea –Formaldehyde) MF (Melamine- formaldehyde) PF (Phenol-Formaldehyde),MELAMINE FORMALDEHYDE RESIN(MELMAC)(MF), NATURAL RUBBER, VULCANISATION, SYNTHETIC RUBBER, Butadiene rubber(BR), polybutadiene, Buna-S, BUNA- N, EPDM ( ethylene, propylene, diene monomer) , Neoprene, silicone rubber, Pollution due to plastics , and recycling of plastics are the other topics discussed here.

1. Commercial polymers
Dr.Lali Thomas Kotturan
Associate Professor in Chemistry
Little Flower College, Guruvayoor, Kerala.

2. POLY OLEFINES
 HDPE,(Highdensity polythene)
 LDPE, (lowdensity polythene)
 PP (Polypropelene)
 PS (Polystyrene)

3. Low-Density Polyethylene (LDPE)
high branching , less tightly packed , and less crystalline
Chain Length: 1000 - 2000

4. Low-density polyethylene (LDPE)
 LDPE is formed from ethylene at a high pressure of 1500-3000 atmosphere at
a temperature range of175-250oC in presence of some oxygen, peroxide, or
azocompounds as initiators.
 LDPE has nearly 20–50 branches (both long and short branches) per 1000
linear carbon atoms in the chain molecules.
 The loss of molecular symmetry due to the high degree of branching results
in a lower density range (0.915–0.94 g/cm3 ) and lower softening or melting
temperature.
 LDPE dissolves in toluene at or above 60°C

5. High-Density Polyethylene (HDPE)
less branching, tightly packed, and has high tensile strength.
Chain Length: 10,000 – 100,000

6. High-density poly ethylene (HDPE)
 The polymerization at a low temperature and pressure in presence of metal
oxide catalyst
 HDPE is usually more resistant to chemicals than LDPE.
 HDPE is soluble in toluene at 900C.
 2–5 short branches or side chains per 1000 carbon atoms in the main chain,
thus having a higher density range (0.945–0.96) and high melting temperature
(125–130°C) compared to LDPE.

7. USES Of POLYETHYLENE
 Polyethylenes are very good insulating materials and are adequately flexible
hence used as an insulator in wires and cables.
 They find extensive uses and applications as molded or formed objects, films,
sheets, bottles and containers, pipes, and tubes.
 Polythene finds application in packaging, waterproofing, irrigation, and water
management including canal lining and mulching, and in coating and
lamination.

8. PP (Polypropelene)

9. POLYPROPYLENE contd…….
 Addition polymer
 Thermoplastic
 Monomer propylene
USES
For making household appliances
In package industry
For making plastic parts of machinery
For making plastic furniture
For making syringes, medical vials, Petri dishes, pill containers, specimen bottles

10. Polypropylene contd…….

11. POLY STYRENE (PS)

12. POLYSTYRENE
 An addition polymer
 Styrene is the monomer
 Amorphous and transparent
 synthesized by the polymerization of styrene at 335K in the presence of a benzoyl peroxide
initiator.

13. USES OF POLYSTYRENE
 As electrical insulator.
 Expanded polystyrene finds extensive use in packaging and shock absorbing
applications, in thermal insulation, and as acoustic improvers in halls and
auditoria.
 High impact grades are suitable for use as toys, games and sports articles,
casings and cabinets for electrical/ electronic gadgets and equipment, and
inner liners of refrigerators.
 Another major use of polystyrene is in the making of ion-exchange resins.

14. KEVLAR- Poly(para-phenyleneterephthalimide)
 Aromatic polyamide
 Five times more tensile strength than steel
 polycondensation polymer
 Monomers are p-phenylene diamine [p-H2N-(C6H4)-NH2] and terephthaloyl chloride. [p-ClOC-
(C6H4)-COCl].

15. USES OF KEVLAR
 Used in industrial applications, such as cables, ropes,
body/vehicle armor, brake linings, bulletproof body
armors.
 To make high-performance structural composites in
aircraft components, boat hulls, and high-performance
cars.
 For making Friction products and gaskets
 For making Adhesives and sealants
 For making Protective apparel in automobile and Aircraft
 For making tennis strings

16. Kevlar
Strong Network of Covalent Bonds
And Polar Hydrogen Bonds

17. VINYL POLYMERS
POLY VINYL CHLORIDE(P.V.C.)
 Addition polymer
 Monomer-vinyl chloride
Synthesis
At 293 K in presence of hydrogen peroxide.
USES
In manufacture of pipes, equipment parts
For covering wires and cables.

18. PVC – (polyvinyl chloride)
Chain Length: 4,000 – 5,000
More Polar  Stronger Bonding

19. POLYVINYL PYROLIDONE(PVP)(POVIDONE)
 Water soluble amorphous, thermoplastic
 Monomer is N-vinylpyrolidone.
 Azobisisobutyronitrile (AIBN) is the freeradical initiator for synthesis of PVP
USES
1. Because of its ability to form film, acts as emulsion stabilizer, suspending agent,
hair fixative, binder is used in mascara, eyeliner, hair conditioners, hair sprays,
shampoos, and other hair care products. it forms a thin coating over the hair
that helps to maintain it in the position you wish.
2. Is used as a surfactant.
3. A food additive. Good taste masker
4. used in the pharmaceutical industry as a synthetic polymer vehicle for dispersing
and suspending drugs. It also acts as a disintegrant and tablet binder.

20. PVP continued……

21. ETHYLENE VINYL ACETATE (EVA)
Co polymer
Monomers are Ethylene and vinyl acetate.
An elastomer
Thermoplastic
USES
1. Used as adhesive.
2. Used as foam
3. To make rubber chappals
4. To make souls of shoes.
5. To make antislippery foams.

22. ETHYLENE VINYL ACETATE (EVA)

23. ETHYLENE VINYL ACETATE (EVA)………

24. SARAN
 Copolymer of 87% vinylidene chloride and 13% vinyl chloride.
 An addition polymer.
 Commercially available as saran wrap for wraping food materials.
 First manufactured by Dow chemical company.
 excellent chemical resistance to many chemicals including acids, alkalis, bleaches, oils, and
most organic solvents.

25. TEFLON (polytetrafluoroethylene) – A
fluoro polymer
Addition polymer
Monomer is tetrafluoroethylene.
TEFLON is the trade name.
Catalysed by oxygen or peroxide.
Strong ,tough, waxy, inflammable resin. Highly slippery. Resistent to ozone, chlorine
and acids. Reacts with molten alkali metalsand fluorinating agents.
USES
Coatings of surgical blades.
Non stick pan coatings
In paints
For coating on metal surfaces and optical devices.

26. POLYACRYLONITRILE (PAN)
 An addition polymer
 A fiber- also called as acrylic fibre
 Monomer is acrylonitrile
 polymerization of acrylonitrile using redox catalysts at or near room temperature.
 Starch and ceric ion, hydrogen peroxide etc. are good redox catalysts.

27. USES OF PAN
 A good fiber
 Wool can be replaced by PAN as In bulkiness, feel and warmth, the acrylic
fibers are very much similar to wool.
 They are widely blended with other fibers, particularly wool, to form various
textile items.

28. Poly(Methyl Methacrylate) (PMMA)
 An addition acrylic polymer
 Monomer is methyl methacrylate.
 using peroxide or azonitrile initiators
at about 100°C, preferably in the absence of air.

29. USES OF POLYMETHYL METHACRYLATE
 PMMA is used for making an automotive tail lamp, signal light lenses, jewelry,
lenses of optical equipment, and contact lenses.
 Used in display and advertisement applications;
 Application in the building industry is also notable. Perspex, Plexiglass, Lucite
and Acrylite are common trade names.
 Used in paints and enamel applications.
 In dentistry for making denture bases.

30. USES OF POLYMETHYL
METHACRYLATE…………..

31. Poly(Hexamethylene Adipamide): Nylon 66
 A condensation or Chain growth polymer
 Monomers are hexamethylene diamine and adpic acid.
 The first 6 in 66 denotes number of carbon atoms in
diamine and second 6 denotes the number of carbon
atoms in diacid.
 Reaction occurs at 523K
 An aliphatic polyamide

32. USES OF NYLON 66
Used for making stockings,
socks, and tights.
Used for making fishing nets,
brush bristles, ropes, etc.

33. Nylon 6
 An aliphatic polyamide (All polyamides are called as Nylon)
 Monomer is caprolactum
 6 indicates number of carbon atoms in caprolactum.
 Caprolactam is heated with traces of water (acting as the catalyst) and traces of acetic acid
(chain length regulator) are charged into a reactor and heated at 250°C under a blanket of
nitrogen for 10–12 h.

34. Nylon

35. USES OF NYLON 6
 1. Widespread applications for the manufacture of gears, bearings, bushes, etc.
 2. Nylon films feature low odor transmission and are useful in packaging for foodstuffs,
drugs, and pharmaceuticals.
 3. Nylon 6 and nylon 66 are melt-spun into fibers or filaments and the fibers and cords
made from them are extensively used as reinforcing agents for plastics and rubbers (in the
construction of composites including hoses and beltings and as tyre cords).

36. KEVLAR- Poly(para-phenyleneterephthalimide)
 Aromatic polyamide
 Five times more tensile strength than steel
 polycondensation polymer
 Monomers are p-phenylene diamine [p-H2N-(C6H4)-NH2] and terephthaloyl chloride. [p-ClOC-
(C6H4)-COCl].

37. USES OF KEVLAR
 Used in industrial applications, such as cables, ropes,
body/vehicle armor, brake linings, bulletproof body
armors.
 To make high-performance structural composites in
aircraft components, boat hulls, and high-performance
cars.
 For making Friction products and gaskets
 For making Adhesives and sealants
 For making Protective apparel in automobile and Aircraft
 For making tennis strings

38. Terylene
 A polycondensation polymer
 Polyester
 Other name is dacron
 Monomers are terephthalic acid and ethylene glycol
 The reaction occurs at 423-473 k under vacuum.

39. USES OF TERYLENE
Terylene is extensively used in the textile
industry to make hard-wear clothes like
sarees, and dress material.
It is mixed with a natural fiber like cotton
and wool to make more variety of clothes.
Used for making plastic bottles.

40. GLYPTAL
 Thermosetting polyester , copolymer, step growth polymerisation
 Monomers- ethylene glycol and phthalic acid.
USES
For making paints and laquars
For making enamel.

41. Polycarbonate (lexan)
Polycarbonate resin. Thermoplastic.
Copolymer- Trade name Lexan (given by SABIC company)
Monomers- Bisphenol A and Phosgene
Heat resistant and flame retardant property, transparent to visible light
USES
A good electrical insulator
For making electrical and telecommunication hardware
Used in capacitors
Coated in eyewear lenses to protect eye from UV light.
Used in sunglass lenses, swimming goggles and scuba masks.
For making domelights, vehicle headlamp lenses.
Used in electronic display sreens of mobile and portable devices.
For making light weight luggage, CD,DVD and blue ray discs.
For making roofing sheet

42. Polycarbonate (lexan)……..

43. POLYURETHANES
Elastomer, Thermoset polymer, linked by carbamate or urethane linkages (HNCOO).
Copolymer made from di or tri cyanates with polyols
USES
 For home furnishings such as furniture, bedding and carpet underlay.
 As a cushioning material for upholstered furniture
 insulation of refrigerators and freezers.
 building insulation.

44. FORMALDEHYDE RESINS
o These are Thermosetting plastics which can withstand high temperatures.
o The nature of the product depend on catalyst used and the molar ratio of the
reactants.
o Condensation polymer under suitable temperature pressure and catalyst.
EXAMPLES
 UF( Urea –Formaldehyde)
 MF (Melamine- formaldehyde)
 PF (Phenol-Formaldehyde)

45. PHENOL-FORMALDEHYDE RESIN(PF).-
Bakelite
 A condensation polymer.
 Monomers are phenol and formaldehyde.
 by the condensation polymerization of phenol with a 75% stoichiometric
quantity of formaldehyde catalyzed by acids or bases. The product formed is
called novlak resins
 If formaldehyde is taken in excess three-dimensional polymer bakelite resins
are formed.

46. Bakelite continued

47. MELAMINE FORMALDEHYDE RESIN(MELMAC)(MF)
As plywood and particleboard adhesives,
To make laminated countertops and tabletops, dishwasher-safe tableware, and automotive surface
coatings.
Mixed with cellulose, wood flour or mineral filters to make unbreakable crockery, dinnerware and
bowls.
Used as insulating and soundproofing materials.

48. Urea Formaldehyde resin (UF)
 As binders for wood boards
 For textile finishing
 Used in moulded plastic industries

49. RUBBERS
 NATURAL RUBBER
polymer of isoprene (2-methylbuta-1,3-diene)
cis polyisoprene .
All isoprene units are attached head to tail fashion.
Gutta Percha is a natural rubber like elastomer obtained from the tree
Palaquium in the family Sapotaceae

50. VULCANISATION
 Vulcanization is heating of natural rubber with Sulphur.
 Short chains of Sulphur atoms are introduced between polymer chains of natural
rubber.
 The stiffness depends on the amount of Sulphur added. Increase in Sulphur
decreases the elasticity of rubber.
3-5% S-used for making tyres and belts
30% Sulphur – for making battery cases.
32% Sulphur-ebonite or hard rubber- noelasticity, tough, Abrasion resistant, good
electrical insulation property.
 Advantages
1. Rubber becomes stiff
2. Improves strength and resilience
3. Greater tensile strength, extendability, resistance to wear and tear, greater
mouldability.

51. SYNTHETIC RUBBER
The polymers which has the properties of natural rubber
are called synthetic rubbers.
Monomers are butadiene or their derivatives
Formed either by homo polymerisation or
copolymerization.
Buna Rubbers are examples for synthetic rubber
BU-Butadiene
Na- catalyzed by sodium.

52. Butadiene rubber(BR), polybutadiene
 Monomer is butadiene.
 Polymerisation can take place in three ways. Cis - 1,4 ;trans1-4 or vinyl-1,4.
Applications
1. For making tyre
2. As toughening agents in plastics
3. For making golf balls.
4. As a coating in electronic assemblies.

53. Buna-S (styrene butadiene rubber),SBR.
 Copolymer of Buta1,3-diene And Styrene in presence of sodium or redox initiators
like hydrogen peroxide or ferrous sulphate.
USES
For making tyre.
For making shoes.
insulating wires and cables.
as adhesive,
for making lining of vessels
Advantage
Can be vulcanized with Sulphur.
Blends verywell with natural rubber.
Superior to natural rubber in mechanical strength and abrasion resistance.

54. BUNA- N (nitrile rubber)
 Copolymer of 1,3 butadiene and vinylcyanide(acrylonitrile)
 Presence of sodium or redox initiators such as hydrogen peroxide and ferrous
sulphate.
USES
can be vulcanized with Sulphur
good resistant to oils , hence used as oil resistant applications.
to manufacture automobile and aircraft parts, conveyer belts and
adhesives.

55. EPDM ( ethylene, propylene, diene monomer)
Monomers ethylene, propylene and diene cross linked with Sulphur .
Heat, ozone and weather resistant.
USES
Automotive. This is EPDM’s most common application. weather stripping, seals,
sealant, wire and cable harnesses, and brake systems.
Industry.- hoses, and gaskets, as well as in electrical insulators and connectors
for wire and cable.
Construction – roofing, pool and tank liners, and waterproof coating .

56. Neoprene (polychloroprene)
 Monomer is chloroprene
 Vulcanised in the presence magnesium oxide.
 Very resistant to chemicals and oils , heat, light and oxygen.
USES
To make hoses, shoe- heels, containers for hydrocarbons and corrosive
chemicals.
for making conveyer belts, adhesives, gaskets, pipes
for making pipes for carrying gases and oils.

57. silicone rubber
 Synthetic organosilicon polymer
 R2SiO repeating units.
 Si-O- Si linkage.
USES
For making gaskets and seals, wire and cable insulation, heat resistant
containers, for making surgical devices.

58. Pollution due to plastics
1. Plastics may remain in soil without degradation and prevent seepage of water into
soil, adversly effecting ground water levels.
2. The poisonous substances like ethylene oxide, benzene, xylene etc. may affect
blood, kidneys, may cause birth defects to cancer.
3. Recycling of plastics is uneconomical as recycling may lower the quality of product
which necessitates the production of more plastic to make the original product.
4. Plasic when burnt produce the poison dioxins into the air.
5. Landfills using plastic is dangerous as it causes seepage of toxic substance to soil
contaminating soil and water. The poisonous substances released include heavy metals
like cadmium and lead.
6. Animals may mistakenly eat plastic waste which may clog their intenstine and leads
to slow starvation.
7. Plastic waste causes clogging of water which may become breeding ground for
mosquitoes. May lead to flood too.

59. Recycling of plastics
 STEPS OF RECYCLING
1. The waste plastic is cleaned by washing
2. Fabricating- Cutting, bending and fixing.
3. Remelting
4. Moulding or extrusion- either converted into useful objects or pellets are made for future reuse.
 Advantages
1. Reduces the accumulation of plastic waste atdisposal sites.
2. Recycling reduces water, air and soil pollution.
3. Reduces global warming as there is reduction in burning of plastic.
4. Reduces the use of fossil fuels like petroleum as the raw materials for plastics are petroleum products.
5. Recycling generates job opportunities as recycling plants require workers.
 Limitations
1. Recycling is not cost effective as the building up of recycling plant requires lots of capital and the recycling
equipments are costly.
2. The quality of recycled products are inferior.
3. Poor management of recycling units leads to unhygienic conditions that may effect the health condition of
workers adversely. Pathogens accumulated in these cites may spread to locality. The poisonous gas may be
released to air from these waste plastics.