Mechanism and kinetics of epoxy-imidazole cure studied with two kinetic methods

Abstract

Curing kinetics and mechanism of the diglycidyl ether of bisphenol-A (DGEBA) initiated with 2-ethyl-4-methylimidazole (EMI-2,4) were studied with two methods by using differential scanning calorimetry (DSC). Method I and Method II were deduced by assuming a constant E and a variable E, respectively. With Method I, the cure reaction activation energy E, the frequency factor A and the overall order of reaction m + n are calculated to be 49.03 KJ mol-1, e14.5 and 1.22, respectively. With Method II, E is proved to decrease initially, and then increase as the cure reaction proceeds, and the value of E spans from 34.3 to 63.84 KJ mol-1. The variations of E were also used to study the cure reaction mechanism. Method I and Method II are effective as long as they are used in proper aspects. With these two methods used all together, we can have a comprehensive and in-depth understanding of the cure reactions, such as those of the DGEBA/EMI-2,4 system.