Synthesis and properties of poly(acrylonitrile-co-p-trimethylsilylstyrene) and poly(acrylonitrile-co-p-trimethylsilylstyrene-co-styrene)

Abstract

Copolymerization of acrylonitrile (AN) with p-trimethylsilylstyrene (TMSS) was carried out at 60°C in bulk and in solution in the presence of 2,2′-azobisisobutyronitrile (AIBN). The reactivity ratios of AN (M1) and TMSS (M2) were determined to be r1 = 0.068 and r2 = 0.309. The effects of the AIBN concentration and that of the chain transfer agent CCl4 on the molecular weights (MWs) of the copolymers were investigated. An increase in the concentrations of AIBN or CCl4 in solution led to a decrease in MW. Poly(AN-co-TMSS-co-St) was synthesized in solution using AIBN as the initiator. The molar fraction of AN was 0.415, while the molar ratio of TMSS/St varied from 1 : 1 to 1 : 9. The transition temperatures and thermal and thermooxidative stabilities of poly(AN-co-TMSS) and poly(AN-co-TMSS-co-St) were investigated. The differential scanning calorimeter technique was used to determine the compatibility of the poly(AN-co-TMSS) and poly(AN-co-TMSS-co-St) with commercial poly(AN-co-St). All the blends show a single glass transition temperature, which indicates the compatibility of the blend components. The surface film morphology of the blends mentioned above was examined by X-ray photoelectron spectroscopy. The data obtained indicate that the silicon-containing copolymer is concentrated in the surface layer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1920–1928, 2000