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

Copolymerization of acrylonitrile (AN) with p-trimethylsilylstyrene (TMSS) was carried out at 60 degrees C in bulk and in solution in the presence of 2,2'-azobisisobutyronitrile (AIBN). The reactivity ratios of AN (M-1) and T MSS (M-2) were determined to be r(1) = 0.068 and r(2) = 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. Po ly(AN-eo-TMSS-co-St) was synthesized in solution using AIBN as the initiato r. The molar fraction of AN was 0.415, while the molar ratio of TMSS/St var ied from 1 : 1 to 1 : 9. The transition temperatures and thermal and thermo oxidative stabilities of poly(AN-co-TMSS) and poly(AN-co-TMSS-co-St) were i nvestigated. The differential scanning calorimeter technique was used to de termine 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 transi tion 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 sili con-containing copolymer is concentrated in the surface layer. (C) 2000 Joh n Wiley & Sons, Inc.