Jyri K. Paulasaari, W. P. Weber
Jul 16, 1999
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0
Influential Citations
9
Citations
Journal
Macromolecules
Abstract
1-Hydrido-1-vinyldimethylsiloxy-3,3,5,5-tetramethylcyclotrisiloxane (IV) was prepared by reaction of tetramethyldisiloxane-1,3-diol and 1,1-dichloro-1-hydrido-3,3-dimethyl-3-vinyldisiloxane (III). Ring-opening polymerization of IV catalyzed by either triflic acid or dilithium diphenylsilanediolate yields high molecular weight poly[1-hydrido-1-vinyldimethylsiloxy-3,3,5,5-tetramethyl-1,3,5-trisiloxanylene] (V), which has an exceptionally low Tg. On the other hand, hydrosilylation polymerization of IV catalyzed by the 1,3-divinyltetramethyldisiloxane platinum complex (Karstedt catalyst) gives high molecular weight alt-copoly(3,3,5,5-tetramethylcyclotrisiloxane-1,1-ylene/2,2-dimethyl-1-oxa-2-sila-1,4-butanylene) (VI). The structures of V and VI were confirmed by IR, 1H, 13C, and 29Si NMR spectroscopy as well as by elemental analysis. Differences in the microstructure of V, formed by acid- or base-catalyzed ring opening of IV, were detected by 29Si NMR. The molecular weight distributions of V and VI were deter...