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Effect of silanol on the thermal stability of poly[methyl(trifluoropropyl)siloxane]
Author(s) -
You Yang,
Chen Jianding,
Zheng Anna,
Wei Dafu,
Xu Xiang,
Guan Yong
Publication year - 2020
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.49347
Subject(s) - silanol , siloxane , thermogravimetric analysis , thermal stability , polymer chemistry , monomer , polymer , chemistry , reaction mechanism , materials science , chemical engineering , organic chemistry , catalysis , engineering
Poly[methyl(trifluoropropyl)siloxane] (PMTFPS), which is an essential polymer in oil‐resistant rubber materials, exhibits unsatisfactory thermal stability. In this article, PMTFPSs with methyl and hydroxyl terminal groups are prepared, and their thermal stabilities are investigated via thermogravimetric analysis and pyrolysis‐gas chromatography‐mass spectrometry in an inert atmosphere. Additionally, the degradation mechanisms are discussed in terms of molecular structural characteristics (bond length and bond angle) and reaction driven forces (electrostatic potential and atom charge) based on quantum chemistry calculations. PMTFPS is found to degrade mainly into cyclic monomers through (a) the SiO rearrangement reaction in the middle of the chain and (b) the “back‐biting” reaction from the end of the chain. PMTFPS with silanol terminal groups is more likely to degrade according to pathway (b), resulting in more cyclotrisiloxane. Furthermore, the silanol from nano‐silica accelerates the degradation of PMTFPS, and the mechanism of this process is presented.