Borate-Catalyzed Thermolysis of Polymethylsilane

Polymethylsilane (PMS) with a general formula [−(CH 3 SiH) 1 - y −(CH 3 Si) y −] n has been synthesized by Würtz type polycondensation of methyldichlorosilane. Copolycondensation with dimethylchlorosilane was realized in an attempt to control the viscosity of the PMS. Thermal reactions at 230 °C with small amounts (1 wt %) of boron derivatives such as B[OSi(CH 3 ) 3 ] 3 serve to cross-link this Si−H-containing organosilicon polymer. As a result, when the products of these reactions are pyrolyzed at 1000 °C under argon, the ceramic residue yields are increased considerably over those obtained with the original polymers.