Solid State NMR Analysis on the Conversion Process of Poly(Si-isocyanato-Si-methylpolysilazane) into Silicon Nitride Oxide†
Takahiro GUNJI, Yoshinori SUZUKI and Yoshimoto ABE*
Department of Industrial Chemistry, Faculty of Science and Technology, Science University of Tokyo; 2641 Yamazaki, Noda-shi 278-8510 Japan
The ceramization process of poly(Si-isocyanato-Si-methylpolysilazane)(MPZ-6) was investigated by means of the ceramic yield on pyrolysis, carbon content analysis, and solid-state cross-polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) spectra. On the pyrolysis of MPZ-6 under ammonia atmosphere, isocyanato and methyl groups were eliminated at about 400 °C to provide silicon nitride oxide at 700 °C. The 29Si, 13C, and 15N CP/MAS NMR spectra showed disappearance of the signals due to silylmethyl and silylisocyanato groups and appearance of the signals due to nitride oxide SiN4−nOn (n=0−4) unit structures, when the pyrolysis temperature was raised. In addition, the S/N ratio decreased in the 13C CP/MAS NMR spectra, due to the elimination of carbon on heating. MPZ-6 was amorphous after the pyrolysis at 1400 °C.
† Syntheses and Properties of Poly(Si-methylpolysilazane)s as a Precursor for Silicon Nitride. Part 2.
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