Spontaneous Ring-Opening Copolymerization of 1,1,2,2-Tetramethyl-1,2-Disilacyclobutane with Styrene

Abstract

l,l,2,2-Tetramethyl-l,2-disilacyclobutane (TMDSCB), obtained by alkali metal vapor dehalogenation of l,2-bis(chlorodimethylsilyl(ethane, undergoes room-temperature spontaneous ring-opening Copolymerization with styrene (St) and results in a rubbery copolymer (M w = 1.6 × 105, M w/M n = 4.4). In contrast to a thermoplastic homopolymer of TMDSCB (m.p. 110°C) that is obtained by the same procedure in the absence of styrene, the copolymer exhibits two-phase behavior (Tg = − 37°C, m.p. 106°C), with the heat of melting being considerably lower in the case of the copolymer (cf. 49.0 and 4.8 J g−1). Spectral and analytical data are consistent with a copolymer structure, [(Me2SiCH2CH2SiMe2) k (CH2CHPh)l] n , where k = 3, l = 1 (36%), and k = 6, l = 2 (64%).