The Reactivities of Nuclear-Substituted Phenyl Methacrylates in Radical Copolymerization with Styrene

In order to clarify the effects of the alkyl substituents on the reactivities of methacrylate monomers toward the attack of a radical, the copolymerizations of a series of nuclear-substituted phenyl methacrylates with styrene were investigated. From the results, the monomer reactivity ratios and the Alfrey-Price Q, and e values were determined. It was found that the relative reactivities toward the polystyryl radical were not correlated with the ordinary Hammett equation, but a linear relationship was obtained with a modified Hammett equation which contained a term of the resonance contribution by the substituents. Accordingly, it was considered that the reactivities of substituted phenyl methacrylates depend on both polar and resonance effects caused by the substituents.