ELASTICITY

Rubber consists of individual molecules called monomers. The monomers bind together to form long chains, so-called polymers. These long polymer chains are unstructured and intermingled.

In this state, rubber does not possess the elasticity we usually associate it with. It can be shaped (possesses plasticity) because the polymers can slide between one another. The elasticity of rubber is created by means of vulcanisation. During vulcanisation, bridges containing sulphur, peroxide or other molecules are formed between the polymers, bonding them together.

Vulcanisation thus "locks" the polymers in place, and they can no longer slide freely between one another. The polymer chains are only able to slide between one another to a limited extent before the bridges prevent further displacement and pull them back into their original position. This characteristic elasticity is quite unique in rubber.