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NATURAL RUBBER:
The organic polymers possessing elasticity to the extent of nearly 200 to 300 percent are known as elastomers or rubber.
TYPES OF RUBBER:
There are two types of rubber
1.Natural rubber: Natural rubber is obtained from latex, a milky emulsion, collected from rubber tree. It is nothing but the milky white watery emulsion of isoprene.
Structure of natural rubber: Natural rubber is cis-polyisoprene which can be represented as,
Due to cis form, the polymer develops coiled structure, and hence possesses elasticity. In cis-form, the distance between groups lying in the same plane is 8.1A0 and methyl groups are oriented outward.
Coiled structure of natural rubber :
Drawbacks of natural rubber
1- Get damaged under the action of strong acid, ozone, oils, greases and fats.
2- Not recommended for use in alcohols, esters, or among the aromatic solution.
3- Low temperature properties.
4- Higher raw material prices.
5- Does not apply to hot water being.
6- Cannot be used in power transmission systems.