Synthesis of Star-Like Poly(n-butyl acrylate)-b-Poly(methyl methacrylate) Block Copolymers as Thermoplastic Elastomers

摘要

Recently, it was demonstrated that thermoplastic elastomers based on star block copolymers may exhibit improved properties in comparison with the linear ABA triblock copolymers. For example, multi-arm polystyrene-b-polyisobutylene star block copolymers have shown much lower sensitivity to diblock contamination and substantially better mechanical properties than their linear triblock counterparts. For the synthesis of star-shaped polymers two major strategies, arm-first and core first, can be employed. The arm-first technique involves use of multifunctional linking agent for bonding of preformed polymer chains. The core-first strategy utilizes multifunctional initiators from which polymer chains are grown. For example, calixarene and dipentaerythritol derivatives having between 3 and 24 functional groups were used as initiators for ring opening polymerizations of lactones or for atom transfer radical polymerization (ATRP) of vinyl monomers.