Journal of Applied Polymer Science, Vol.117, No.6, 3220-3227, 2010
Curing Mechanisms and Kinetic Analysis of DGEBA Cured with a Novel Imidazole Derivative Curing Agent Using DSC Techniques
A novel imidazole derivative, 2MI-g-CA, was obtained through the reaction of 2-methylimidazole (2MI) and cyanuric acid (CA) and characterized by means of elemental analysis, FTIR spectroscopy, H-1 NMR spectroscopy, and mass spectrometric analysis. The curing mechanisms and kinetics of diglycidyl ether of bisphenol A (DGEBA) using 2MI and 2MI-g-CA as curing agents were studied with differential scanning calorimetry (DSC) under dynamic and isothermal conditions. Both dynamic and isothermal DSC thermograms of DGEBA/2MI system showed two distinct exothermic peaks, whereas those of DGEBA/2MI-g-CA system showed only one distinct exothermic peak. These results indicated that the two systems have different initiation curing mechanisms. The apparent activation energies (E-a) obtained from DSC scanning runs using the Kissinger and Ozawa methods were 79.0, 83.0 kJ/mol and 84.2, 88.8 kJ/mol for DGEBA/2MI and DGEBA/2MI-g-CA systems, respectively. These values suggested the novel curing agent 2MI-g-CA exhibited greater levels of latency during cure or increased the pot life of epoxy resin system. In addition, under the same curing condition, the T-g values of DGEBA/2MI-g-CA system were about 25 degrees C higher than those of DGEBA/2MI system, exhibiting a better thermal stability. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 3220-3227, 2010