Silicon Carbide Base Ceramic Fiber Synthesis from Polycarbosilane-Polymethylsilane Blend Polymers by Melt Spinning

A melt-spinnable precursor for SiC based fibers was prepared from blend polymers of polycarbosilane (PCS) and polymethylsilane (PMS). After melt spinning, thermal oxidation curing, and pyrolysis, Si-C-O fibers were obtained. The addition of a small amount of PMS (0.2 or 0.5 mass%) to PCS was effective in increasing the resulting ceramic yield at 1273 K. Fiber decomposition temperature of the obtained Si-C-O fibers shifted to higher temperature (~100 K) by the PMS addition. For high PMS content (20 mass%), however, cross-linking of the blend polymers made the spinning process impossible. Doping of a radical trapping agent in the starting blend polymers was effective in preventing the cross-linking process. Si-C-O fibers with high oxygen content and reduced C/Si ratio were obtained in this case.