8 - Thermoplastic Elastomers

Abstract

This chapter describes thermoplastic elastomers. Thermoplastic elastomers (TPEs) have two advantages over the conventional thermoset (vulcanized) elastomers. The advantages being ease and speed of processing. Other advantages of TPEs are recyclability of scrap, lower energy costs for processing, and the availability of standard uniform grades. TPEs are molded or extruded on standard plastics processing equipment. They are made by copolymerizing two or more monomers, using either block or graft polymerization techniques. One of the monomers provides the hard or crystalline, polymer segment that functions as a thermally stable component; the other monomer develops the soft or amorphous segment which contributes the elastomeric or rubbery characteristic. Block techniques create long-chain molecules that have various or alternating hard and soft segments. Graft polymerization methods involve attaching one polymer chain to another as a branch. The properties that are affected by each phase can be generalized as hard phase and soft phase.