Stoichiometric silicon carbide from borate-catalyzed polymethylsilane–polyvinylsilane formulations
✍ Scribed by Bruno Boury; Nathan Bryson; Gérard Soula
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 121 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0268-2605
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✦ Synopsis
Polymethylsilane (PMS) and polyvinysilane (PVS) were prepared by Wurtz condensation of chlorosilanes and characterized by spectroscopy ( 1 H, 13 C and 29 Si NMR, and infrared), viscosity and GPC analysis. Mixtures of the PMS and PVS were prepared and stabilized with 2,6di-t-butyl-4-methylphenol (BHT; 0.5 wt%) to which was added a catalytic amount of tris (trimethylsilyl)borate, B(OSiMe 3 ) 3 (BTMS; 2 wt% by weight). The resulting liquid materials were pyrolyzed to 950 °C and to 1400 °C under argon. The formulation, composed of 60% PMS / 40% PVS / 2% BTMS, was pyrolyzed and gives nearly stoichiometric silicon carbide in 73% yield. The pyrolyzate was analyzed spectroscopically at intermediate stages in order to study its thermal transformations and the influence of the boron catalyst. The ceramic obtained from the formulation 60% PMS / 40% PVS / 2% BTMS shows good stability at 1500 °C under oxygen.