Thermal reactions occurring during pyrolysis of crosslinked polysiloxane gels, precursors to silicon oxycarbide glasses

摘要: The pyrolysis under argon of three polysiloxane gels, MeSiO1.5, PhSiO1.5 and crosslinked oligovinylsiloxane, was investigated by 29Si solid-state NMR thermogravimetric analysis coupled to mass spectrometry. Above 500–600°C, redistribution reactions involving the exchange Si-C Si-O bonds take place, which lead a random environment silicon atom at 1200°C. use oligovinylsiloxanes hydrosilation leads high yields oxycarbide glasses with an O/Si ratio close 1.