Isoconversional models toward the curing kinetics of self-healable epoxy resin TGDDM and acid anhydride

The reaction process and curing mechanism of self-healable epoxy resin TGDDM and curing agent TA are complicated. In this paper, the curing reaction kinetic mechanism of the system is studied from the perspective of isoconversional models. The nth-order model and autocatalysis model are established for observations of heat flow versus temperature and time during real-time curing obtained by non-isothermal differential scanning calorimetry (DSC), and evaluated under the standards of MSE, RMSE, and R-square. Under the guidance of least squares fitting, the pre-exponential factor (A), the activation energy (E-alpha), the order of models (n, m) and other parameters in f(alpha) of the model are mainly estimated by Kissinger method, Ozawa method, Malek method, and other methods. The correlation between the activation energy (E-alpha) of the reaction and the degree of conversion alpha also analyzed by the Flynn-Wall-Ozawa method. The chemical reaction of the system is studied by Fourier transform infrared (FTIR) and the self-healing property of the system is characterized by scanning electron microscope (SEM). It was found that the esterification reaction occurred in the system, and the realization of the self-healing property was also due to the transesterification reaction. In addition, the effect of the accelerator on the system is analyzed by the established autocatalysis model and dynamic mechanical analysis (DMA). The result shows that the addition of the accelerator does not change the curing reaction mechanism of the system, but accelerated the reaction process and increased the glass transition temperature.