Synthese und charakterisierung von poly(dialkenylsilylen-co-methylenen) als grundmaterialien von SiC-Fasern

Abstract

The synthesis of new poly(dialkenylsilylene-co-methylenes) of the general composition (SiR 2CH 2) x (with R  CHCH 2, CH 2CHCH 2, CH 2C(CH 3)CH 2, (CH 2) 2CHCH 2, (CH 2) 3CHCH 2) was achieved by the Grignard reaction of the educt poly(dichlorosilylene-co-methylene) with alkenylmagnesiumhalides. The products obtained were characterized by elemental analysis and by IR, 1H, 13C and 29Si NMR spectroscopy. The ceramic residues were determined via pyrolysis. The molecular weight distribution was investigated by gel permeation chromatography. Green fibres were formed from poly(diethenylsilylene-co-methylene). The fibres were cured into an infusible state by UV irradation or by peroxidic catalysts. The precursor fibres were heated up to 1000°C and 1700°C, and oxygen-free SiC-based ceramic filaments were prepared.