Thermal and thermoxidative decomposition of a heat-resistant poly(dimethylsilylene ethynylenephenyleneethynylene) resin

Poly(silylene arylacetylene) resins (PSA resins) show excellent thermal stability under inert atmosphere but weak thermoxidative stability under aerobic environment. The thermal and thermoxidative decomposition of the cured poly(dimethylsiliylene ethynylenephenyleneethynylene)(PSA-M) resin was comparatively investigated in this article. The pyrolysis-gas chromatography-mass spectrometry was used to analyze the decomposed products and determine the structure of the PSA-M resin. The thermogravimetric analysis coupled to fourier transform infrared spectroscopy and mass spectrometry (TGA-FTIR-MS) and normal fourier transform infrared spectroscopy (FTIR) is used to investigate the decomposition mechanism. In combined TGA-FTIR-MS technique, Fourier transform infrared spectroscopy and mass spectrometry were used to detect the volatile products from TGA instrument. Normal FTIR was used to determine the chemical structures of the TGA residues at different temperatures under oxygen-free and aerobic atmospheres. The results show the decomposition under the oxygen-free atmosphere (N-2) mainly undergoes the cleavage of the side groups on silicon atoms, the release of degraded fragments and the dehydrogenated carbonization. The oxidation decomposition mainly undergoes the oxidation of residual internal alkyne groups, the oxidation cleavage of the side groups on silicon atoms and the decomposition of the oxidized products. The decomposition mechanisms for the PSA-M resin under oxygen-free and aerobic atmospheres are separately suggested.

Automated summary

Poly(silylene arylacetylene) resins (PSA resins) exhibit good thermal stability under inert atmosphere but poor thermoxidative stability under aerobic environment. This article comparatively investigates the thermal and thermoxidative decomposition of cured poly(dimethylsiliylene ethynylenephenyleneethynylene)(PSA-M) resin, and analyzes the decomposed products and structure using pyrolysis-gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy and mass spectrometry.