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Curing of epoxy resins with citric acid–piperazine salt
Author(s) -
Galego N.,
González F.,
Vazquez A.
Publication year - 1996
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(199607)40:3<213::aid-pi551>3.0.co;2-f
Subject(s) - piperazine , diglycidyl ether , epoxy , differential scanning calorimetry , curing (chemistry) , materials science , glass transition , thermal decomposition , polymer chemistry , salt (chemistry) , nuclear chemistry , chemistry , bisphenol a , organic chemistry , polymer , composite material , physics , thermodynamics
Citric acid–piperazine salt was prepared with a molar ratio of acid–piperazine of 2.9. The salt was characterized by thermal calorimetry, 13 C NMR and IR spectroscopy. The piperazine content in the salt was 52%. A typical formulation was achieved by mixing the salt with the diglycidyl ether of bisphenol A (DGEBA). The heat of reaction was measured by a calorimeter and the evaluated peak resulted from the simultaneous endothermic salt decomposition and exothermic network formation. The heat of reaction value was −Δ H = 18kJ/eq. for the stoichiometric ratio, and the glass transition temperature, T g , was 95°C. The heat of reaction evolved and the T g value of piperazine–epoxy were determined for comparison with the salt–epoxy system.