thermolysis of crosslinked polysiloxanes
Si—C/Si—O and Si—H/Si—O bonds exchange
thermogravimetric analysis/mass spectroscopy
Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
The thermolysis under argon of various polysiloxane resins containing D, T, DH, or TH units was investigated using thermogravimetric analysis combined with mass spectroscopy (TG/MS analysis) and solid-state 29Si-NMR. Redistribution reactions involving the exchange of Si—C/Si—O bonds or Si—H/Si—O bonds were evidenced in addition to the exchange of Si—O/Si—O bonds reported to date. These reactions significantly modify the initial siloxane units and lead to an escape of volatile silanes or siloxanes. The exchange of Si—H/Si—O bonds takes place at lower temperatures (300°C) than the exchange of Si—C/Si—O bonds (500°C).
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