Curing of Epoxy Resins with Citric Acid-Piperazine Salt

✍ Scribed by Galego, N.; González, F.; Vazquez, A.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 314 KB
• Volume: 40
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199607)40:3<213::aid-pi551>3.0.co;2-f

✦ Synopsis

Citric acid-piperazine salt was prepared with a molar ratio of acidpiperazine of 2.9. The salt was characterized by thermal calorimetry, 13C 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 -AH = 18 kJ/eq. for the stoichiometric ratio, and the glass transition temperature, T,, was 95°C. The heat of reaction evolved and the T, value of piperazine-epoxy were determined for comparison with the salt-epoxy system.