Study on thermal degradation kinetics of bio-based semi-aromatic high-temperature polyamide PA5T/56 and the effect of benzene ring

The process and mechanism of thermal degradation of the bio-based semi-aromatic high-temperature polyamide PAST/56 in nitrogen (N-2) and air atmosphere were studied using thermal degradation kinetics of PAST/56 at different heating rates (Phi(h)) under N-2 atmosphere by thermogravimetric analysis. The results showed that the thermal degradation process of PAST/56 in N-2 was a one-step reaction, consistent with the thermal degradation mechanism of conventional polycondensation reaction products, and thermal degradation temperature increased with the increase in Phi(h). Different atmospheric conditions were shown to alter the thermal degradation process of polyamide; the thermal degradation process of PAST/56 in air atmosphere was similar to that under N-2, except in air the degradation was a two-step reaction with additional oxidation cross-linking process. The thermal degradation activation energies of PAST/56 were calculated by the Kissinger method, Flynn-Wall-Ozawa method and Coats-Redfern method to be 154.11 kJ/mol, 178.24 kJ/mol and 166.56 kJ/mol, respectively. In addition, the thermal degradation activation energy of PAST/56 increased with the increase in benzene ring content. Finally, the thermal degradation of bio-based semi-aromatic high-temperature polyamide PAST/56 was proven to be a phase boundary reaction by the Coats-Redfern method.

Automated summary

The thermal degradation process of bio-based semi-aromatic high-temperature polyamide PAST/56 was studied under different atmospheric conditions. The results showed that the degradation process differed in nitrogen and air atmosphere, with the latter involving an additional oxidation cross-linking process. The thermal degradation activation energy was found to be related to the benzene ring content.