Thermogravimetric Analysis of a New Series of Trimellitimide-Based Epoxy-Imide Resins

The dynamic thermogravimetric analysis of a new series of aliphatic, cycloaliphatic, and aromatic trimellitimide-based epoxy-imide (EI) resins, compared to diglycidyl ether of bisphenol-A (DGEBA) and triglycidyl isocyanurate (TGIC) resins, in uncured and cured states, revealed that the EI resins/ systems, unlike DGEBA ones, have a multistep thermal degradation process with two chief steps corresponding to the degradation of the DGEBA and the imide moieties. Evaluating the influences of isothermal curing temperature (T_Cure) on their degradation behavior ascertained that, generally, the 1^st stage of the thermal degradation processes is more affected by T_Cure. Furthermore, the competition between epoxide-amine reactions with etherification/ homopolymerization plays the most crucial role in the impact of T_Cure on the systems' stability and decomposition behavior. Therefore, the most considerable changes can be observed in the thermograms of the cycloaliphatic system due to the highest difference between the melting temperature of its resin and T_Cure.