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Effects of chemical structure of hardener on curing evolution and on the dynamic mechanical behavior of epoxy resins
Author(s) -
De Nograro F. F.,
Guerrero P.,
Corcuera M. A.,
Mondragon I.
Publication year - 1995
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.1995.070560208
Subject(s) - diglycidyl ether , epoxy , differential scanning calorimetry , dynamic mechanical analysis , curing (chemistry) , glass transition , materials science , natural rubber , steric effects , polymer chemistry , activation energy , composite material , chemistry , bisphenol a , polymer , thermodynamics , organic chemistry , physics
A diglycidyl ether of bisphenol‐A‐type difunctional epoxy resin was cured with different amine‐type curing agents at stoichiometric ratios. The crosslink process was followed by viscosimetry and differential scanning calorimetry. The gelation time and the apparent activation energy were found to be strongly dependent on the structure of the hardener. The heat of reaction did not vary significantly when the hardener was changed. An interpretation based on structural aspects such as amine reactivity, steric hindrance, and chain rigidity is proposed for the variations corresponding to the curing process. Master viscosity curves have been built up for all mixtures. The effect of the hardener on the glass transition temperatures of the different mixtures has been analyzed taking into account the crosslink density, measured by the rubber modulus obtained by dynamic mechanical studies, and the chemical structure of the hardener chains. © 1995 John Wiley & Sons, Inc.