Thermoplastic Elastomers - A Major Innovation in Rubber

Abstract

The worldwide growth rate of thermoplastic elastomers (TPEs) is 3 to 5 times that of either the rubber or the plastics industry, a pace which likely will be maintained until the end of this century. These novel materials have numerous processing and performance advantages, and some disadvantages. Their chief advantage, however, is the ease, reproducibility and economy of thermoplastic processing. The unique combination of thermoplastic processing and subsequent rubber properties is derived from the two-phase morphology of these materials. Virtually all TPEs consist of a hard thermoplastic phase, and a soft elastomeric phase. The useful temperature range of a TPE lies between the melting point (T_m) of the hard phase and the glass transition temperature (Tg) of the elastomeric phase. Existing TPEs are (1) block copolymers consisting of alternating hard and soft monomer blocks, (2) blends of a thermoplastic and an elastomer, or (3) alloys of these two polymers. TPEs now have a broad variety of properties and performance features, with their cost generally increasing with these two parameters. With the exception of pneumatic tyres and low volume rubber parts, it is now practical to fabricate virtually all other rubber articles from a TPE.