Photoinduced reverse atom transfer radical polymerization of methyl methacrylate using camphorquinone/benzhydrol system

A versatile initiating system composed of camphorquinone/benzhydrol and Cu^IIBr₂/N,N,N′,N″,N″-pentamethyldiethylenetriamine for photoinduced reverse atom transfer radical polymerization has been developed. The control experiments, where each component is eliminated in the reaction, serve as a direct verification of the mechanism. There is poor or no control over the polymerization of methyl methacrylate in the absence of either camphorquinone or benzhydrol. The experimental molecular weights are considerably higher than theoretical values and the obtained polymers show slightly broad molecular weight distributions ranging from 1.13 to 1.51 in the process. Although at relatively lower polymerization rates, the addition of an alkyl halide to the system leads to a better control of the polymerization as reflected by the improved molecular weight distribution and chain-end functionality.