Novel thermoplastic elastomers based on arborescent (dendritic) polyisobutylene with short copolymer end sequences

This article presents the synthesis and initial characterization of polymers having a high molecular weight dendritic (arborescent) polyisobutylene (arbPIB) core and short end sequences composed of copolymers of isobutylene with isoprene, p‐methyl styrene, or cyclopentadiene. The first stage of the polymerizations was controlled/living (i.e., no chain transfer or irreversible termination were detected) and the process was reproducible. The hydrodynamic radii of arbPIBs were measured by viscometry and quasi‐elastic light scattering, and good agreement between the two methods is demonstrated for the first time in this paper. Sequential addition of the second monomer(s) led to the formation of short copolymer end sequences. We have discovered that regardless of the T_g of the copolymer end blocks, the new block copolymers exhibited TPE properties, which were improved by carbon black and silica fillers to a great extent. These novel PIB‐based TPEs are promising new biomaterials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1148–1158, 2009