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Microstructure evolution of ammonia‐catalyzed phenolic resin during thermooxidative aging
Author(s) -
Guo DanDan,
Zhan MaoSheng,
Wang Kai
Publication year - 2012
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.36550
Subject(s) - fourier transform infrared spectroscopy , thermogravimetry , materials science , glass transition , attenuated total reflection , spectroscopy , polymer chemistry , infrared spectroscopy , catalysis , chemistry , chemical engineering , composite material , organic chemistry , polymer , inorganic chemistry , physics , quantum mechanics , engineering
The thermooxidative aging of ammonia‐catalyzed phenolic resin for 30 days at 60–170°C was investigated in this article. The aging mechanism and thermal properties of the phenolic resin during thermooxidative aging were described by thermogravimetry (TG)–Fourier transform infrared (FTIR) spectroscopy, attenuated total reflectance (ATR)–FTIR spectroscopy, and dynamic mechanical thermal analysis. The results show that the CN bond decomposed into ammonia and the dehydration condensation between the residual hydroxyl groups occurred during the thermooxidative aging. Because of the presence of oxygen, the methylene bridges were oxidized into carbonyl groups. After aging for 30 days, the mass loss ratio reached 4.50%. The results of weight change at high temperatures coincided with the results of TG–FTIR spectroscopy and ATR–FTIR spectroscopy. The glass‐transition temperature ( T g ) increased from 240 to 312°C after thermooxidative aging for 30 days, which revealed the postcuring of phenolic resins. In addition, an empirical equation between the weight change ratio and T g was obtained. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012