Vinyl Chloride Copolymerization. Penultimate Effects with Conjugated Comonomer

A kinetic study of the radical copolymerization of vinyl chloride with acrylonitrile, methyl methacrylate, or styrene, using the chromatographic method, shows that penultimate effects are observed in all cases, chiefly for the acrylonitrile case (r_cc = 0.03, r_ac = 3.0). The conjugated monomer induces a stronger penultimate effect than the unconjugated vinyl chloride; this effect might be correlated with the e values of the Q-e scheme. A strong antepenultimate effect is observed on the styrene ended radicals (r_sss = 3.0, r_css = 20.0, r_scs = 18.5, r_ccs = 2.7), which might be related to a steric effect.