Rubber

The production of rubber

More than half of all the rubber produced goes to car tires, therefore the use of rubber in the automobile industry is also huge. The rest of the rubber produced goes into mechanical parts such as fasteners, gaskets, belts and hoses and consumer products such as shoes, clothing, furniture and toys.

The main chemical constituents of rubber are elastomers or “elastic polymers,” large chain-like molecules that can be stretched to great lengths and still regain their original shape.

The first common elastomer was polyisoprene, from which natural rubber is made. Natural rubber is formed in a living organism and consists of solids suspended in a milky liquid called latex, which circulates in the inner parts of the bark of many tropical and subtropical trees and shrubs.

Natural rubber continues to occupy an important place in the marketplace. Its resistance to heat build-up makes it valuable for tires used in racing cars, trucks, buses and airplanes. Yet natural rubber is only less than half of commercially produced rubber. The rest of rubber production consists of synthetically produced rubber through chemical processes.

These processes were known as far back as the 19th century, but it was not until the 2nd half of the 20th century that these processes were used commercially. The main synthetic rubbers include butadiene rubber, styrene-butadiene rubber, neoprene, the polysulfide rubbers (thiocols), butyl rubber and the silicone rubber. Synthetic rubbers, like natural rubbers, can be hardened by vulcanization and, for special purposes, improved and modified by reinforcement with other materials.