Preparations and Polymerizations of p-Substituted Phenyl Vinyl Sulfides. Vinyl Polymerization 168

Abstract p-Substituted phenyl vinyl sulfides (PVS) were prepared and their radical polymerizations were investigated dilatometrically to determine some kinetic constants and to deduce the influences of the sulfur atom and p-substituents of PVS. It was found that PVS could be easily homopolymerized by ordinary radical polymerization mechanisms in the presence of 2,2′-azobisisobutyronitrile, contrary to the case of phenyl vinyl ethers, which do not homopolymerize. From the rates of polymerization (Rp H) of PVS and those of p-substituted PVS (Rp X) under the same conditions, the plot of log (Rp H/Rp X) against the Hammett's equation was found to give a parabola curve. When these results were plotted by the modified Hammett's equation [log (kp X/kp H) = ρσ + γER ], however, a straight line with γ = −4.5 and ρ = 0.35 was obtained. From these results it was concluded that the 3d orbital resonance was important in the transition state of the polymerization of these monomers.