PREPARATION AND CHARACTERIZATION OF POLY[(4-VINYLPHENYL)DIMETHYLVINYLSILANE] VIA ANIONIC LIVING POLYMERIZATION

(4-Vinylphenyl)dimethylvinylsilane (VS) was anionically polymerized to yield poly[(4-vinylphenyl)dimethylvinylsilane] (PVS). The styryl grou p of VS was polymerized and silylvinyl group of VS remained unreacted during the anionic polymerization. However, a slight amount of the sil ylvinyl group of VS should be subject to anionic polymerization. To su ppress two side reactions related to the silylvinyl group, the influen ce of initiators, solvents and polymerization time on anionic polymeri zation was studied in detail. When n-butyllithium was used as initiato r, the resultant polymer conversion rate was 60% and the corresponding GPC chromatogram showed a broad peak. This is because during chain pr opagation, the styryl living end was deactivated by a labile proton of the silylmethyl group of the side chain (abstraction mechanism). When cumylpotassium and cumylcesium were used as initiators, the polymer c onversion rates were nearly 100% and corresponding GPC chromatograms s howed double and/or triple peaks because after chain propagation had c ompletely finished, the styryl living end reacted with the silylvinyl group of the side chain of a different polymer molecule (addition mech anism). When a mixture of diethyl ether/4,4-dimethyl-1,3-dioxane (1,3- DX) was used as solvent, PVS yielded a sharp GPC chromatogram containi ng a small shoulder at the higher molecular weight side. The size of t his shoulder increased with polymerization time. Thus, VS was polymeri zed by cumylcesium in a 1:2 mixture of diethyl ether/1,3-DX for 30 min utes to yield four polymers with M-n from 2.5(0) x 10(4) to 1.3(6), x 10(5), and M-w/M-n less than 1.0(8). Upon exposure to a deep ultraviol et light having a wavelength of 290 nm, gel of PVS was observed in the exposed area.