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 degrees 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.