Disproportionating Versus Nondisproportionating Solvent Effect in the SET-LRP of Methyl Acrylate During Catalysis with Nonactivated and Activated Cu(0) Wire

The disproportionating solvent effect on the kinetics of single electron transfer living radical polymerization (SET-LRP) during catalysis with nonactivated Cu(0) wire coated with Cu2O and activated Cu(0) wire free of Cu2O was studied. In solvents such as dimethyl sulfoxide, MeOH and ethylene carbonate that in conjunction with Me-6-TREN promote extensitve disproportionation of Cu(I)X, faster polymerizations were achieved upon switching from nonactivated Cu(0) wire to activated Cu(0) wire. The results showed that the substantial rate enhancement was accompanied with excellent control of molecular weight evolution and distribution, and high fidelity of chain-end functionality. This can be attributed to a more effective equilibrium between activation and deactivation in the presence of Cu(0) free of Cu2O. In nondisproportionating solvents, the kinetics of SET-LRP of methyl acrylate catalyzed by activated Cu(0) wire resembled that of the polymerizations catalyzed by nonactivated wire. This is the result of a competing effect between rapid activation and insufficient disproportionation. The absence of disproportionation effectively leads to the lack of first order kinetics, broad molecular weight distribution, significant loss of bromide chain-end functionality, and therefore, the absence of a living polymerization. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 42274240, 2011