Synthesis and characterization of novel preceramic polymer for SiC

Polyphenylcarbosilane as a novel preceramic polymer for SiC was synthesized by thermal rearrangement of polymethylphenylsilane at around 350–430 °C. Characterization of the synthesized polyphenylcarbosilane was performed using 29Si NMR, 13C NMR and 1H NMR spectroscopy, FT-IR spectroscopy and TG, XRD, and GPC analysis. From the FT-IR data, the band at 1035 cm−1 was very strong and was assigned to the CH2 bending vibration in the Si–CH2–Si group, indicating the formation of polyphenylcarbosilane. The average molecular weight (Mw) of the polyphenylcarbosilane synthesized was 2,500, and it was found to easily dissolve in an organic solvent. TGA data indicate that polyphenylcarbosilane is thermally stable up to 200 °C. However, rapid weight loss occurs above 200 °C because of the decomposition of polyphenylcarbosilane, and the diffraction peak of the pyrolysis residue at 1200 °C corresponds to β-SiC ceramic. The ceramic yield calculated from TGA is approximately 60%.