Styrene-Butadiene Rubber (abbreviated SBR) describes families of synthetic rubbers derived from styrene and butadiene. About 50% of car tires are made from various types of SBR. The styrene/butadiene ratio influences the properties of the polymer, in which, with high styrene content, the rubbers are harder and less rubbery.
SBR is a commodity material which competes with natural rubber. The elastomer is used widely in pneumatic tires. Some other applications include shoe heels and soles, gaskets, and even chewing gum. It is also used in building applications, as a sealing and binding agent behind renders.