COMPOSITION CONTROL OF CERAMIC CHARS DERIVED FROM METHYLPOLYSILANES

A process for the preparation of a methylpolysilane having a controlled carbon content is provided which includes the steps of heating together to form a reaction mixture at leasdt one alkoxy-functional disilane selected from the group consisting of disilanes having two, three, and four alkoxy groups bonded to the silicon atoms, and mixtures thereof, with either an alkoxy-functional silane having at least one unsaturated substituent or an unsaturated hydrocarbon compound in an amount effective to increase the carbon content of the resulting polymer. The reaction is carried out in the presence of a catalyst which is a source of alkoxide ions. The methylpolysilane polymers produced may be pyrolyzed to form ceramic compositions having increased carbon contents. The ceramics may find use as films, fibers, and coatings, as well as the many other uses to which silicon carbide ceramics have heretofore been put.