Liquid crystalline and isotropic epoxy thermosets: Mechanism and kinetics of non-isothermal degradation

Thermal non-oxidative degradability of two epoxy thermosets was studied. Investigations were carried out on a non-commercial liquid crystalline structure and its isotropic homologue in order to provide further insight into the mechanism and kinetics of thermal degradation of the proposed systems. The studies were done by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). For the first time the degradation of a liquid crystalline epoxy was studied using an advanced isoconversional kinetic method. The results were used to predict the thermal stability of both types of epoxy networks. GC-MS analysis was applied on evolved gas during degradation to elucidate the degradation mechanism in accordance with the kinetic results. The liquid crystalline structure has a different mechanism of decomposition in comparison with its isotropic homologue. In spite of a higher Tg value, it shows a similar thermal stability but a lower release of degradation compounds.