Synthesis and characterization of polyvinylsilazane as a precursor for Si3N4 based ceramic materials
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This investigation focused on the synthesis and characterization of a polyvinylsilazane (PVSZ) polymer. This material shows promise as a precursor for silicon nitride/silicon carbide based ceramic materials. The polymer was synthesized via the ammonolysis of vinyltrichlorosilane (VTS) in tetrahydrofuran (THF). The polymer was characterized using Fourier Transform Infrared (FT-IR) spectroscopy, 1H/13C nuclear magnetic resonance (NMR) spectroscopy, and gel permeation chromatography (GPC). This polymer was found to have a molecular weight of around 880 g/mol, as determined by GPC. Thermal cross-linking, up to 1500 °C in an inert atmosphere, produced a ceramic material with a char yield of around 85%. The gas by-products from the partial decomposition of the polymer to a ceramic material were characterized using residual gas analysis (RGA). The crystallite phases of the ceramic char, pyrolyzed in different atmospheres, were determined by X-ray powder diffraction (XRD). Lastly, the ability of the polymer to form a free standing monolithic structure as well as the ability to be drawn into fibers was evaluated.
KeywordsNuclear Magnetic Resonance Spectrum Nuclear Magnetic Resonance Spectroscopy Char Yield Ultra High Purity Dicumyl Peroxide
The authors would like to thank Pratt & Whitney for their funding and support of this work. We also thank Dr. Martha Morton for training and interpretation of the NMR and Mark Dudley for GPC analysis. We would also like to thank Dr. Francis Galasso, Dr. Evan Benbow, and Dr. Raymond Joesten for editing and encouragement.
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