Copolymerization of acrylonitrile (AN) and ethyl methacrylate (EMA) using copper-based atom transfer radical polymerization (ATRP) at ambient temperature (30 degrees C) using various initiators has been investigated with the aim of achieving control over molecular weight distribution. The effect of variation of concentration of the initiator, ligand, catalyst, and temperature on the molecular weight distribution and kinetics were investigated. No polymerization at ambient temperature was observed with N,N,N ',N ',N ''-pentamethyldiethylenetriamine (PMDETA) ligand. The rate of polymerization exhibited 0.86 order dependence with respect to 2-bromopropionitrile (BPN) initiator. The first-order kinetics was observed using BPN as initiator, while curvature in first-order kinetic plot was obtained for ethyl 2-bromoisobutyrate (EBiB) and methyl 2-bromopropionate (MBP), indicating that termination was taking place. Successful polymerization was also achieved with catalyst concentrations of 25 and 10% relative to initiator without loss of control over polymerization. The optimum [bpy](0)/[CuBr](0) molar ratio for the copolymerization of AN and EMA through ATRP was found to be 3/1. For three different in-feed ratios, the variation of copolymer composition (FAN) with conversion indicated toward the synthesis of copolymers having slight changes in composition with conversion. The high chain-end functionality of the synthesized AN-EMA copolymers was verified by further chain extension with methyl acrylate and styrene. (c) 2006 Wiley Periodicals, Inc.