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

The relative reactivities of butadiene, isoprene, 2,3-dimethylbutadien e, 2,3-diphenylbutadiene and methyl methacrylate with the 1-methyl-1-( methoxycarbonyl)ethyl radical have been evaluated by using the 'polyme r end-group method', and the data obtained compared with those for the same monomers in their reactions with the poly(methyl methacrylate), 1-cyano-1-methylethyl and 1-phenylethyl radicals. The observed reactiv ity trends can be explained by variations in the and and e values for the monomers, and show that the 1-methyl-1-(methoxycarbonyl)ethyl radi cal is a good model for the poly(methyl methacrylate) radical. Further results indicate that a penultimate styrene unit does not affect the reactivity of a poly(methyl methacrylate) radical, whereas a penultima te methacrylonitrile unit does.