REACTIVITIES OF MONOMERS TOWARDS THE 1-METHYL-1-(METHOXYCARBONYL)ETHYL RADICAL

The relative reactivities of acrylonitrile, methyl acrylate, methyl me thacrylate and styrene towards the 1-methyl-1-(methoxycarbonyl)ethyl r adical 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 m ethyl methacrylate unit in a poly(methyl methacrylate) radical leads t o a slightly greater preference for this radical to add styrene over m ethyl methacrylate compared to the 1-methyl-1-(methoxycarbonyl)ethyl r adical. The results for methyl methacrylate and acrylonitrile suggest that the copolymerization of these monomers is probably best represent ed by a penultimate mechanism.