Facile synthesis of comb, star, and graft polymers via reversible addition-fragmentation chain transfer (RAFT) polymerization

Reversible addition-fragmentation chain transfer (RAFT) polymerization has been shown to be a facile means of synthesizing comb, star, and graft polymers of styrene. The precursors required for these reactions were synthesized readily from RAFT-prepared poly(vinylbenzyl chloride) and poly(styrene-co-vinylbenzyl chloride), which gave intrinsically well-defined star and comb precursors. Substitution of the chlorine atom in the vinylbenzyl chloride moiety with a dithiobenzoate group proceeded readily, with a minor detriment to the molecular weight distribution. The kinetics of the reaction were consistent with a living polymerization mechanism, except that for highly crowded systems, there were deviations from linearity early in the reaction due to steric hindrance and late in the reaction due to chain entanglement and autoacceleration. A crosslinked polymer-supported RAFT agent was also prepared, and this was used in the preparation of graft polymers with pendant polystyrene chains. (C) 2002 Wiley Periodicals, Inc.