BORATE-CATALYZED THERMOLYSIS OF POLYMETHYLSILANE

Polymethylsilane (PMS) with a general formula [-(CH3SiH)(1-y)-(CH3Si)( y)-](n), has been synthesized by Wurtz type polycondensation of methyl dichlorosilane. Copolycondensation with dimethylchlorosilane was reali zed in an attempt to control the viscosity of the PMS. Thermal reactio ns at 230 degrees C with small amounts (1 wt %) of boron derivatives s uch as B[OSi-(CH3)(3)](3) serve to cross-link this Si-H-containing org anosilicon polymer. As a result, when the products of these reactions are pyrolyzed at 1000 degrees C under argon, the ceramic residue yield s are increased considerably over those obtained with the original pol ymers.