Premium
High temperature oxidative degradation of phenol–formaldehyde polycondensates
Author(s) -
Jackson William M.,
Conley Robert T.
Publication year - 1964
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.1964.070080516
Subject(s) - char , phenol , formaldehyde , pyrolysis , chemistry , thermogravimetric analysis , degradation (telecommunications) , thermal stability , thermal oxidation , carbon monoxide , reaction mechanism , carbon fibers , infrared spectroscopy , polymer chemistry , organic chemistry , photochemistry , materials science , catalysis , composite material , telecommunications , silicon , computer science , composite number
Abstract The degradation of phenol–formaldehyde polycondensates has been investigated at temperatures as high as 1000°C. By employing infrared spectrophotometric techniques and vapor‐phase chromatographic methods, as well as thermogravimetric and x‐ray analyses, it has been possible to examine the oxidation chemistry of this resin system. It has been found that the primary degradation route of phenol–formaldehyde polycondensates, regardless of whether the resin is exposed to elevated temperatures in air, argon, or nitrogen, is oxidation. At elevated temperatures, products are observed from thermal pyrolysis in addition to those from the oxidation path. However, throughout the temperature region studied, the oxidative degradation is always more pronounced. The mechanism of oxidation has been found to agree favorably with the proposals formulated earlier by Conley and Bieron. It is also possible to extend this mechanism to include the formation of graphitelike char. This extension is postulated on the simultaneous formation of the char and carbon monoxide. By infrared studies of the intermediate stages in char formation, the postulation that these products arise from quinone‐type intermediates is justified. In this study, it was found that phenolformaldehyde polycondensates of unusual thermal stability could be produced by high temperature postcuring. The comparison of the oxidation rates of the resin cured at low temperature and this material indicates greatly improved oxidative stability, as well as resistance to thermal pyrolysis. This undoubtedly is due to the complete crosslinking of the resin system.