SYNTHESIS OF POLY(DIMETHYLSILYLENE-CO-DIPHENYLSILYLENE) POLYMERS AS PRECURSORS FOR SIC CERAMICS

Silicon carbide ceramics, especially fibres, are being fabricated via polymeric precursors. Although such fibres are commercially available, there is a demand for improved performance particularly at elevated temperatures. A range of copolymers has been synthesized from the monomers, dimethyldichlorosilane and diphenyldichlorosi lane, by a Wurtz reaction involving dechlorination using sodium metal in xylene. The products of reaction were characterised by a range of techniques, including gel permeation chromatography (GPC), infra-red spectroscopy (IR), X-ray powder diffraction (XRD) and thermogravimetry (TG).