Synthesis and characterization of semicrystalline triblockcopolymers of isotactic polystyrene and polydimethylsiloxane

Abstract

iPS-b-PDMS-b-iPS triblock copolymers were prepared by hydrosilylation of vinyl-terminated isotactic polystyrenes (iPS) with α,Iω- bis(dimethylsilane)-terminated poly(dimethylsiloxane)s (PDMS). As a function of the molecular weights of the two components, the triblock copolymer composition was varied between 9.0 and 98 wt % iPS. The resulting triblock copolymers remained soluble during block copolymer synthesis due to slow iPS crystallization in solution. At iPS content exceeding 31 wt %, the iPS crystallization was achieved by postpolymerization annealing and melt processing. The triblock copolymers melted above 200 °C with melting temperatures very similar to those of the corresponding iPS homopolymers. Nanostructure and microstructure formation of both amorphous and semicrystalline triblock copolymers were examined by means of light microscopy, atomic force microscopy, and TEM measurements. © 2011 Wiley Periodicals, Inc.