Preface

Thermoplastic elastomers (TPEs), sometimes referred to as thermoplastic rubbers, are a class of co‐ polymers or a physical mix of polymers (usually a plastic part and a rubbery part) which consist of materials with both thermoplastic and elastomeric properties. A TPE is a rubbery material with prop‐ erties and functional performance similar to those of conventional vulcanized rubber at ambient tem‐ perature; yet it can be processed in a molten state as a thermoplastic polymer at an elevated temperature. Most of the elastomers are thermosets; thermoplastics are in contrast relatively easy to manufacture, for example, by injection molding. A TPE shows advantages typical of both rubbery materials and plastic materials. The principal difference between thermoset elastomers and thermo‐ plastic elastomers is in the type of the crosslinking bond in their structures. In fact, crosslinking is a critical structural factor which contributes to imparting high elastic properties. TPEs are a class of polymers bridging between the service properties of elastomers and the processing properties of thermoplastics. Thus, TPEs combine the conventional rubbers and thermoplastics. They provide the simplest way of achieving outstanding properties by simply varying the blend compositions and the viscosity of the components and compounding ingredients at a low cost.

A thermoplastic elastomer must fulfill the following three essential characteristics:


TPE materials have the potential to be recyclable since they can be molded, extruded, and reused like plastics, but they have the typical elastic properties of rubbers which are not recyclable owing to their thermosetting characteristics. TPEs also require little or no compounding and do not require the ad‐ dition of reinforcing agents, stabilizers, or cure systems. Hence, batch-to-batch variations in weight‐ ing and metering components are absent, leading to improved consistency in both raw materials and fabricated articles. TPEs can be easily colored by most types of dyes, and more economical control of product quality is possible.

The applications of TPEs are listed below:

Gaskets, Seals, Stoppers, Housings, Rollers, Valves, Bumpers, Wheels, Pads, Casters Strain Reliefs, Cable Jacketing, Switch Contact Points, Bellows, Fuel Line Covers, Housings Shoe Soles/Heels, Wrist Straps, Cushions, Airbag Doors Keycaps, Cosmetic Cases, Handles, Grips, Push Buttons, Knobs

> **Professor Chapal Kumar Das** Materials Science Centre IIT Kharagpur, India
