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Rubber technology
From Wikipedia, the free encyclopedia
Rubber Technology is the subject dealing with the transformation of rubbers or elastomers into useful products, such as car tyres.The materials includes Latex, natural rubber, synthetic rubber and other polymeric materials, such as thermoplastic elastomers.
Most rubber products are vulcanized, a process which involves heating with a small quantity of sulphur (or equivalent cross-linking agent so as to stabiliise the polymer chains. This discovery was made by Charles Goodyear in the 1844, but is a process restricted to polymer chains having a double-bond in the backbone. Such materials include natural rubber and polybutadiene. The range of materials available is much wider however, since all polymers become elastomeric above their glass transition temperature. However, the elastomeric state is unstable because chains can slip past one another resulting in creep or stress relaxation. Chemical cross links add the stability to the network that is needed for most practical applications.
Methods for processing rubber include mastication and calendering, both processes being essential to bring crude rubber into a state suitable for shaping the final product. The former breaks down the polymer chains, and lowers their molecular weight so that viscosity is low enough for further processing. After this has been achieved, various additions can be made to the material ready for cross-linking.
