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Crosslinking of an epoxy with a mixed amine as a function of stoichiometry. II. Final properties via dynamic mechanical spectroscopy
Author(s) -
Wingard Charles D.,
Beatty Charles L.
Publication year - 1990
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.1990.070411101
Subject(s) - epoxy , stoichiometry , diglycidyl ether , glass transition , curing (chemistry) , materials science , bisphenol a , dynamic mechanical analysis , activation energy , polymer chemistry , amine gas treating , kinetics , composite material , ether , polymer , chemistry , organic chemistry , physics , quantum mechanics
Variation of the epoxy/curing agent ratio for a system containing a diglycidyl ether of bisphenol‐A (DGEBA) and a mixed aromatic amine was found to have a significant effect on the cure kinetics and final dynamic mechanical properties of both the neat resin and glass reinforced epoxy. For a partial B‐stage cure to an ultimate C‐stage cure, optimum cure temperatures were obtained as a function of stoichiometry. For the ultimately cured (C‐stage) resin, the molecular weight between crosslinks ( M c ) passed through a minimum, and both the glass transition temperature ( T g ) and a secondary (sub‐ T g ) transition passed through a maximum at the stoichiometric ratio. In addition, the activation energy of the ultimately cured resin passed through a maximum at or near the stoichiometric ratio for both the T g and sub‐ T g transitions.