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Dynamic mechanical analysis study of the curing of phenol‐formaldehyde novolac resins
Author(s) -
Markovic Slobodanka,
Dunjic Branko,
Zlatanic Alisa,
Djonlagic Jasna
Publication year - 2001
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.1623
Subject(s) - curing (chemistry) , formaldehyde , dynamic mechanical analysis , materials science , rheology , phenol formaldehyde resin , order of reaction , kinetics , polymer chemistry , reaction rate constant , composite material , chemistry , polymer , organic chemistry , physics , quantum mechanics
The curing reaction of typical commercial phenol‐formaldehyde novolac resins with hexamethylentetraamine (HMTA) was followed by dynamic mechanical analysis. The evolution of the rheological parameters, such as storage modulus G ′, loss modulus G ″, and tanδ ( G ″/ G ′), as a function of time, for samples of the phenolic resins on cloth, was recorded. The curing reaction, leading to the formation of a crosslinked structure, is described by a third‐order phenomenological equation. This equation takes into account a self‐acceleration effect, as a consequence not only of the chemical reaction of crosslinking after the gel point but of phase segregation as well. This rheokinetic model of the curing of phenolic novolac resins permits the determination of the numerical values of the kinetic equation constants. The influence of the composition, structure, and physical treatment on the curing kinetics of the novolac resins is evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1902–1913, 2001