Method of preparing polycarbosilanes

摘要

A method of preparing polycarbosilanes having high molecular weight and also having the major structural unit of silicon-carbon linkage. The method comprises heating a polysilane at 50 DEG -600 DEG C. in atmosphere of an inert gas and distilling out a low molecular weight polycarbosilane fraction having the number mean molecular weight of 300-600, followed by polymerizing the fraction by heating it at 250 DEG -500 DEG C. in atmosphere of an inert gas. The polycarbosilane obtained by the method of the present invention is useful for the precursor of preparing silicon carbide fibres and shaped articles.