EXAMPLES OF POLYMERS
Rubber occurs in nature as well as it is obtained by synthetic methods.
Natural rubber is obtained as latex from rubber trees. The monomer of natural rubber is isoprene. There may be as many as 11000 to 20000 isoprene units in a polymer chain of natural rubber.
Properties of Natural Rubber
It is soft and sticky material which is insoluble in water. When a rubber piece is stretched, its length increases greatly. And on releasing the stretched rubber piece, it returns to its original size.
Vulcanization of Rubber
The process of heating natural rubber with Sulphur to improve its properties is called vulcanization of rubber. Vulcanization of rubber makes the rubber hard, strong and more elastic and loses its sticky properties.
Hardening of Rubber
Rubber is hardened by adding carbon black in it.
Synthetic rubber means artificial rubber. It is superior to natural rubber. The two important synthetic rubbers are:
- Neoprene rubber, and
a) Neoprene Rubber
The monomer of neoprene rubber is chloroprene. It was prepared in 1931.
Uses of Neoprene Rubber
Following are the uses of neoprene rubber:
- It is used for making insulation of electric wires.
- It is used for making belts in industry and coal mines.
- It is used for making hoses for petrol delivery and transporting oil.
b) Thiokol Rubber
The monomer of Thiokol rubber is ethylene polysulphide.
Polythene is formed by heating ethene at temperature of 460 K to 480 K and applying high pressure.
Uses of Polythene
Following are the uses of polythene:
- It is used for insulation of electric wires.
- It is used in manufacture of bags, toys and pipes.
Polypropene is formed by polymerization of propene.
Uses of Polypropene
Following are the uses of polypropene:
- It is used for making carpets, ropes and fishing nets.
- It is used for making seat covers.
It is prepared by polymerization of 1, 3–Butadiene and Styrene in the presence of sodium.
This rubber is called Buna-S-Rubber because in it Bu stands for butadiene, na for Sodium and S for Sulphur.
Uses of Buna-S-Rubber
- It is used for making rubber tyres and footwear.
- It is also used for making belts.
5) Teflon or Polytetrafluoroethane or (PTFE)
Teflon is prepared by polymerization of tetrafluoroethane.
Uses of Teflon
- It is used for making non-stick cooking utesnsils.
- It is used for making gaskets, pump packings and seals.
Nylon is a polyamide fibre. A polyamide fibre is made when a carbon compound containing two carboxylic acid groups is reacted with another carbon compound containing two amino groups.
Nylon is formed by polymerization of hexamethylene diamine with adipic acid.
Uses of Nylon
- It is used for making fibres and ropes.
- It is used for making footwears and bristles of tooth brushes.
A polyester fibre is prepared by polymerization of a dicarboxylic acid with dihydric alcohols. An important example of polyester is terylene.
Terylene is prepared by polymerization of terephthalic acid with ethylene glycol.
Uses of Polyester Fibres
- These are used for making clothes, sarees, dress materials and curtains.
- These are used for making conveyor belts.
- These are used for making sails of sail boats.