ABSTRACT
With the rapid acceptance of thermoplastic elastomers (TPEs) in the past decade, they can hardly be ignored when reviewing rubber compounding; yet the field is so wide, any attempt to be comprehensive would require a separate volume. Although the first TPE was thermoplastic polyurethane which appeared in the 1950s styrene block copolymers, which enjoy a major part of the market, were not available commercially until the 1960s. There are some basic differences between the linear and the radial styrene block copolymers. Unlike polyester, polyurethane and polyamide block copolymers polystyrene block copolymers are not used as copolymers but are compounded with plastics, oils, fillers, resins and stabilizers. The prime use of polystyrene TPEs is in soles for footwear, particularly athletic shoes, either as unit soles or direct molded soles. An elastomeric alloy is a two phase compound with a polyolefin such as polypropylene or polyethylene for the hard phase and vulcanized rubber for the soft phase.
