This book is broadly organized according to the type of rubber or elastomer involved: thermosetting elastomer (TSE) or thermoplastic elastomer (TPE). The terms “elastomer” and “rubber” are used interchangeably.
Adhesion is affected by materials, process, and equipment. It plays a vital role in the success or failure of many rubber composites that involve a broad range of rubber types, adhesives, and substrates. Ease of adhering different types of rubber varies substantially. For example, polar rubbers like NBR are more easily adhered than nonpolar rubbers like EPDM.
Thermoplastic elastomers (TPEs) are rubbery, two-phase materials that can be fabricated like conventional thermoplastics but have the performance characteristics of a TSE [1]. TPEs are self-reinforcing, generally from two or more intermingled polymers that act as separate phases [2].
Among the substantial differences between processes and equipment for TPEs and TSEs are the thermal profiles for the two materials. During molding, a TPE increases in viscosity as it cools in its mold. In contrast, higher temperature first decreases viscosity of a TSE in its mold, and then crosslink formation increases its viscosity. After a TSE extrudate exits its die, increasing temperature decreases both viscosity and dimensional stability.
Copolyester TPEs are said to be easily extruded into blown films with a thickness less than 1 mm [1]. Both the extruder adapter and head should be as streamlined and as short as possible to minimize regions of low flow that can lead to polymer degradation and subsequent random release of degraded polymer.
