Macromolecules, Vol.37, No.10, 3614-3622, 2004
Room temperature atom transfer radical polymerization of glycidyl methacrylate mediated by copper(I)/N-alkyl-2-pyridylmethanimine complexes
The homogeneous controlled/"living" free radical polymerization of glycidyl methacrylate (GMA) by atom transfer radical polymerization (ATRP) using Cu(I)X/N-alkyl-2-pyridylmethanimine complexes with various initiators R-X (X = Cl, Br) and solvents was investigated. Most of these systems display characteristics of a living radical polymerization as indicated by (a) linear first-order kinetic plots of ln[M](0)/[M] vs time, (b) an increase in the number-average molecular weight (M.) vs conversion, and (c) relatively narrow polydispersities indicating a constant number of propagating species throughout the polymerization with negligible contribution of termination or transfer reactions. The dependence of the rate of polymerization on the concentrations of initiator, ligand, and temperature is presented. We observed comparable rates of polymerization linear increase of molecular weight with conversion and low polydispersities in polar solvents. No polymerization was observed in nonpolar solvents such as toluene and xylene at room temperature. The order of controlled polymerization with different initiator system is CuBr/BPN > CuCl/BPN > CuBr/ClPN, and the polymerization did not proceed with CuCl/ClPN initiator system at room temperature. The high functionality of bromine end groups present in the polymer chains was confirmed by ESI MS analysis. The thermal stability of PGMA prepared by the CuBr/PPMI/BPN initiation system is higher than by the other three systems, indicating the high regioselectivity and the virtual absence of termination reactions in the former case. The ligand alkyl chain length from R = propyl to octyl did not affect the rate of polymerization. The molecular weight (M.) increases linearly with conversion, and these polymers showed narrow polydispersities.