Rapid Curing of Liquid Polycarbosilane and Its Conversion into Protective Coating

High ceramic yield, fast curing rate and high purity are essential for ceramic precursors. In this study, a SiC ceramic precursor-polycarbosilane containing both allyl group and acrylate group was synthesized. According to the 1 H-NMR analysis, the molar ratio of allyl group to acrylate group was 10:1. The polycarbosilane can be cured under UV light for only 1 s and photolithography pattern with clear boundary could be formed. After pyrolysis to 1000 °C, the ceramic yield was up to 78 wt% and the pattern could be retained without cracks and deformation. The ceramic product was composed of 63.28 wt% Si, 33.37 wt% C and 3.35 wt% O, and the chemical formula was determined as SiC 1.23 O 0.09 . As a SiC ceramic precursor, the polycarbosilane was used to prepare SiC-based protective coating on carbon fiber. The obtained SiC coating was dense with a thickness of about 150 nm, significantly improving oxidation resistance of the carbon fiber.