Evidence for Termination of Intermediate Radical Species in RAFT-Mediated Polymerization

The reactions of short-chain species during the initial periods of cumyl dithiobenzoate (CDB)-mediated polymerizations of styrene were investigated at 84°C. High initiator and CDB concentrations were chosen such that very short chains were targeted at complete conversion, and high radical concentrations were present. The high radical and RAFT agent concentrations allowed the detailed examination of the nature and concentrations of both radical and nonradical species during the initial stages of the reaction. The probability of side reactions, such as termination of intermediate radicals, was enhanced due to the high concentrations of the potential reactants that were presented.