Mechanism of CPDB-Mediated RAFT Polymerization of Methyl Methacrylate: Influence of Pressure and RAFT Agent Concentration

Reversible addition-fragmentation chain transfer (RAFT) polymerizations of methyl methacrylate (MMA) in bulk at 60 degrees C were performed at five pressures up to 200 MPa using 2-(2'-cyanopropyl)dithiobenzoate (CPDB) as RAFT agent at concentrations between 1.5 x 10(-3) and 2.0 x 10(-2) mol L(-1). Applying high pressure during polymerization increases the rate of polymerization, but no effect on polydispersity was observed. Molecular weight distributions and average molecular weights of the final polymer indicated the successful control of MMA polymerization even at low CPDB concentrations. The slight retardation observed is adequately described by the dependence the termination rate coefficient, k(t), on the chain-length.