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Thermal stability of substituted phenol‐formaldehyde resins
Author(s) -
O'Connor Daniel,
Blum Frank D.
Publication year - 1987
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.1987.070330606
Subject(s) - hexamethylenetetramine , thermal stability , phenol , formaldehyde , chemistry , thermogravimetric analysis , organic chemistry , synthetic resin , distilled water , phenol formaldehyde resin , phenols , alkyl , polymer chemistry , materials science , chromatography
A variety of crosslinked phenol‐, or derivatized phenol‐formaldehyde polymers have been synthesized. The phenol derivatives included o ‐ and p ‐cresol, p ‐nonylphenol, m ‐pentadecylphenol, and raw and distilled cashew nutshell liquid. The derivatives were copolymerized with phenol and formaldehyde using sulfuric acid as catalyst to yield novolak‐type prepolymers, which were then cured with hexamethylenetetramine. Thermogravimetric analysis was used to evaluate the thermal stability of the cured resins. It was found that the thermal stability of the resins decreased with increasing amounts of cashew nutshell liquid, with distilled cashew resins being slightly more thermally stable than raw cashew resins. The thermal stability of resins containing substituted phenols with alkyl chains was observed to increase from n ‐pentadecylphenol to cresol to phenol. The trend in thermal stability of the resins may be explained on the basis of alkyl groups being less thermally stable than aromatic rings. The amount of hexamethylenetetramine used to cure the prepolymers also influences the thermal stability of the resins. It appears that a level of 10 to 15% hexamethylenetetramine maximizes the thermal stability of the resin.