Reactivities of monomers towards the 1-phenylethyl radical: Monomers with low ceiling temperatures

Abstract

The reactivities towards the 1-phenylethyl radical of 2-vinylnaphthalene and some monomers with low ceiling temperatures (α-methylstyrene, 2-isopropenylnaphthalene and α-methoxystyrene) have been assessed by 13C-NMR examination of end-groups in terpolymers prepared at 100° using 13C-enriched azobis-1,1′-phenylethane as initiator. In each case, acenaphthylene has been used with styrene (STY) or methyl methacrylate and a third monomer selected from the quoted list. The present and previous results suggest that, for many monomers, the reactivity towards the 1-phenylethyl radical is very similar to that predicted from data on copolymerizations with STY, regarding the initiating small radical as a model for the polystyrene radical. There are appreciable differences between the observed and predicted relative reactivities in cases where either the copolymerization of the monomer with STY may show quite pronounced penultimate group effects or the monomer has a low ceiling temperature.