The preparation of LPVCS with high ceramic yield and low oxygen content

As by-products produced by the synthesis of polycarbosilane, RLPS and dimethyldivinylsilane (DVS) can synthesise vinyl-containing liquid polycarbosilane (LPVCS) via hydrosilylation reaction. The structure, thermal curing performance and pyrolysis performance of PVCS are characterised by means of the analysis means such as FT-IR, GPC and TG, etc. According to the result, the structure of PVCS is affected by the different synthesised temperatures and different proportions of introduced DVS. And LPVCS that contains Si–H and –CH=CH2 groups is synthesised under the control of reaction condition. Cross-linking solidity is available at 350°C in an inert atmosphere, and the total ceramic yield of LPVCS is 42.5%. The oxygen content of the pyrolysed product is just about 2.0% after heating in 1000°C, which is a suitable precursor polymer for SiC-based composite.