Rubber, which is in common use, is of two types, namely, natural rubber and synthetic rubber. Natural rubber comes from the juice of a tree while synthetic rubber is made from chemicals.
Synthetic rubber was first developed before 1900 from the hydrocarbon isoprene which was synthesized from turpentine. Almost all types of synthetic rubber are obtained from petroleum industry. Important sources are styrene, acetylene and butadiene. Two of the most important types of synthetic rubber are butyl rubber and styrene-butadiene rubber. These two rubbers along with natural rubber made up about 90 percent of the worlds’ demand.
Natural-synthetic rubber is also an important rubber for the industry. These are the synthetics that duplicate the molecular structure of natural rubber and can be used interchangeably with the natural product. Since World War II, a lot of products such as foam rubber have been directly made from natural rubber latex or from synthetic equipment.
Chemists have developed better and better synthetic rubber with different properties. Neoprene rubbers resist oxygen, sunlight, gasoline, oil and other chemicals better than natural rubber does. Nitrile rubber which stands heat upto 177°C is much better than natural rubber. It is used in gasoline hose, leather products and many types of cloth. Polysulphide rubbers such as Thiokol have great resistance to softening and swelling in gasoline and greases. Polyurethane rubbers resist age and heat and withstand remarkable stresses and pressures. Silicone rubbers keep their like properties at much higher and lower temperatures than natural rubber. Silicone rubbers are used in seals, gaskets, and jet plane industry. These rubbers are made of oxygen and silicon with a hydro-carbon added to the silicone. Thermoplastic rubbers are used as shoe soles and automotive parts.
Rubber whether natural or synthetic, is one of the most versatile materials available to industry.
