Solvent Effects on the Radical Copolymerizabilities of Styrene with p-Substituted N,N-Diethylcinnamamides and of p-Substituted Styrenes with Methyl Vinyl Sulfoxide

Radical copolymerizations of styrene (St) with p-substituted-N, N-diethylcinnamamides (I) and also of p-substituted styrenes (II) with methyl vinyl sulfoxide (MVSO) have been carried out in benzene, acetic acid or acetonitrile. The monomer reactivity ratios (r₁) were found to be affected by the solvents, p values obtained by using the modified Hammett equation, i. e., log(1/r₁) = ρσ + γ E_R, were also found to be altered by the solvents. The results are discussed in terms of the solvent effect in the transition state of the propagation reaction.