P-ACETYLBENZYLIDENE TRIPHENYLARSONIUM YLIDE (p-ABTAY) INITIATED RADICAL COPOLYMERIZATION OF METHYLMETHACRYLATE WITH STYRENE

Abstract

p-Acetylbenzylidene triphenylarsonium ylide (p-ABTAY) initiated radical copolymerization of methylmethacrylate (MMA) with styrene in dioxane, at 60 ± 0.1°C, under the inert atmosphere of nitrogen yields alternating copolymer, as evidenced by 1H NMR spectroscopy. The kinetic equation for the present system is Rp μ[p-ABTAY]0.46 [MMA] [Sty]. The rate of copolymerization (Rp) is proportional to the square root of [p-ABTAY] indicating bimolecular termination. The values of kp2/kt and energy of activation have been computed as 6.3 × 10−3 l mol−1s−1 and 63 KJ mol l−1, respectively. The reactivity ratios have been calculated as r1 (MMA) = .60, r2 (Sty) = .35, by using the Kelen-Tudös method. The copolymerization reaction is initiated by the phenyl free radical. The formation of phenyl radicals may be attributed to the pp-dp overlap between the hybridized sp2 orbital and the larger and more diffuse 4d orbital of arsenic.