Styrene-butadiene block copolymers are an important class of synthetic rubbers. The two most common types are linear and radial triblock copolymers having rubber center blocks and polystyrene end blocks. SBS elastomers combine the properties of a thermoplastic resins with those of butadiene rubber. The hard, glassy styrene blocks provide mechanical strength and improve the abrasion resistance, while the rubber mid-block provides flexibility and toughness.
In many regards, SBS elastomers with a low styrene content have properties that are similar to those of vulcanized butadiene rubber but can be molded and extruded using conventional thermoplastic processing equipment. However, SBS is less resilient than chemically crosslinked (vulcanized) butadiene rubber and thus, does not recover as efficiently from deformation as vulcanized diene elastomers.