Facile synthesis of melt-spinnable polyaluminocarbosilane using low-softening-point polycarbosilane for Si-C-Al-O fibers

Melt-spinnable polyaluminocarbosilane (PACS) is of importance as the precursor to prepare the Si–C–Al–O ceramic fibers, which can be employed for the preparation of SiC fibers with high tensile strength and good thermal stability. In this work, low-softening-point polycarbosilane (LPCS) was synthesized by pyrolysis of polydimethylsilane and applied to prepare PACS precursors with variable aluminum content by the reaction with aluminum(III) acetylacetonate. GPC, 1H NMR, UV–Vis, FT-IR, 29Si NMR, 27Al MAS NMR, TGA, and elemental analysis were used to analyze the composition and structure of the PACS precursors. Finally, Si–C–Al–O fibers were obtained successfully by melt-spinning, curing, and final pyrolysis of the precursors. The method demonstrated in this work can be further extended to synthesize other melt-spinnable metal-containing polycarbosilane (PMCS, M: Zr, Ti, Fe, Co, et.) of high ceramic yield and adjustable M content by reacting LPCS with other corresponding metal-containing compounds.