Free radical copolymerization of styrene with vinyl acetate using p‐acetylbenzylidene triphenylarsonium ylide as an initiator

Abstract

Abstractp‐Acetylbenzylidene triphenylarsonium ylide (p‐ABTAY) initiated free radical copolymerization of styrene (Sty) with vinyl acetate (VA) in dioxane, at 65 ± 0.1°C, under the inert atmosphere of nitrogen has been studied. The system follows ideal radical kinetics and the kinetic equation for the system is Rp ∝ [p‐ABTAY]0.5[Sty][VA]. The rate of copolymerization (Rp) is proportional to the square root of [p‐ABTAY] indicating biomolecular termination. The values of kp2/kt and energy of activation have been computed as 5.0 × 10−3 mol l−1 s−1 and 34.0 kJ mol−1 respectively. The reactivity ratios calculated by using Kelen–Tudos method are r1(Sty) = 42.8, r2(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 pπ–dπ overlap between the hybridized sp2 orbital and more diffused 4d orbital of arsenic. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 108–115, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/adv.2000