Reactivities of Monomers Towards the 1-Methyl-1-(methoxycarbonyl)ethyl Radical

The relative reactivities of acrylonitrile, methyl acrylate , methyl methacrylate and styrene towards the 1-methyl-1-( methoxycarbonyl )ethyl radical have been determined at 60°C, and the results compared with those for the poly (methyl methacrylate ) radical. The results for methyl acrylate suggest that the copolymerization of this monomer with methyl methacrylate is adequately described by a terminal mechanism. Those for styrene show that the presence of a penultimate styrene or methyl methacrylate unit in a poly(methyl methacrylate ) radical leads to a slightly greater preference for this radical to add styrene over methyl methacrylate compared to the 1-methyl-1-( methoxycarbonyl )ethyl radical. The results for methyl methacrylate and acrylonitrile suggest that the copolymerization of these monomers is probably best represented by a penultimate mechanism.