p-Acetylbenzylidene triphenylarsonium ylide (p-ABTAY) initiated free radical copolymerization of styrene (Sty) with vinyl acetate (VA) in dioxane, at 65 +/- 0.1degreesC, under the inert atmosphere of nitrogen has been studied. The system follows ideal radical kinetics and the kinetic equation for the system is R-p proportional to [p-ABTAY](0.5)[Sty][VA]. The rate of copolymerization (R-p) is proportional to the square root of [p-ABTAY] indicating biomolecular termination. The values of k(p)(2)/k(t) and energy of activation have been computed as 5.0 x 10(-3) Mol l(-1) s(-1) and 34.0 kJ mol(-1) respectively. The reactivity ratios calculated by using Kelen-Tudos method are r(1) (Sty) = 42.8, r(2) (VA) = 1.0. SEM analysis shows that arsenic is not incorporated in the polymer and the copolymerization reaction is initiated by phenyl free radicals. The formation of phenyl radicals may be attributed to the ppi-dpi overlap between the hybridized sp(2) orbital and more diffused 4d orbital of arsenic.