Curing kinetics and mechanical properties of epoxy resin/1-benzyl-2-methylimidazole/isophorone diamine system

The epoxy resin of diglycidyl ether of bisphenol A (DGEBA) diluted with allyl glycidyl ether (AGE) was mainly cured by 1-benzyl-2-methylimidazole (1B2MZ). Then, the effect of isophorone diamine (IPDA) on the properties of DGEBA-AGE-1B2MZ system was investigated. The differential scanning calorimetry (DSC) results revealed that when the content of 1B2MZ was small, the epoxy groups need to be completely cured by imidazole regeneration, which would be unnecessary with the introduction of IPDA thereby alleviating the burden of 1B2MZ. The variations of the activation energy with the degree of curing determined via Ozawa–Flynn–Wall were various for the studied systems. Calculations based on the Cure Index (CI) approved that the cure states of all the composite systems were affected by the heating rate. Finally, the resin of optimal formula could be cured in 20 min at 120 °C with the best mechanical properties and the glass transition temperature (Tg) of 100.61 °C.