Synthesis, characterization and applications of thermoplastic polyurethane elastomers

Abstract

This chapter reviews the research and the most relevant advances in the investigation of thermoplastic polyurethane elastomers, TPU, and provides a comprehensive source of information on their synthesis, structure, properties and applications. TPUs are multiblock copolymers built up from so-called short, rigid hard segments and long, flexible soft segments. The thermodynamic incompatibility of the hard and soft segments at low temperatures results in phase separation and, consequently, in the formation of a domain structure. Due to their twophase microstructure, TPUs exhibit a combination of unusual thermoplastic and elastomeric behavior. The properties of TPUs depend on many variables, such as the chemical structure of the segments, the ratio of the hard/soft segment content, the molecular weight of the soft segments, the degree of crystallinity of the hard segments, and, in some cases, crystallization of the soft segments and the ability to form discrete crystalline and rubbery or viscous microdomains. The versatility of this class of materials promises that novel TPUs will play a key role in many future biomedical applications. Knowledge of the structure and properties of TPUs and their influence on the biocompatibility of TPUs is of great practical importance; therefore, this chapter also reviews biocompatibility assessment of different TPUs using recent studies presented in the literature. The latest developments in design of TPU nanocomposites, as well as in future trends for TPUs are also presented.