Styrenic-based thermoplastic elastomers by anionic polymerization

Thermoplastic elastomers are copolymers consisting of an elastic matrix that is physically cross-linked by nonmiscible glassy domains. Thanks to the physical cross-linking, TPEs combine the elasticity of a conventional rubber (chemical cross-linking) with the thermoplasticity of a noncross-linked polymer and thus can be processed by various techniques. TPEs are used in a wide range of applications, such as adhesives, elastomers, coatings, fibers, and additives. Styrenic block copolymers, based on styrene (or styrene derivatives) and 1,3-dienes, lead to phase-separated systems which do not require chemical cross-linking. In this chapter, the general principles, as well as the recent advances in design/synthesis, by anionic polymerization, of SBCs (TPE) with different macromolecular architectures, including linear ABA triblock copolymers, ABC triblock terpolymers, multiblock copolymers, star copolymers, and graft copolymers, are presented. In each section, a comparison of the morphology and mechanical properties of the different materials is also discussed.