Synthesis and Thermal Degradation Kinetics of PA6T/66 and PA6T/610 Copolyamides

Abstract

PA6T is one of the most typical high-temperature resistant polyamides, which is widely used in military, transportation and communication fields. As an engineering plastic, thermal stability is a very important point, although there are many studies on copolyamide PA6T, but the in-depth analysis of its heat resistance and thermal degradation process is rarely studied. Therefore, two copolyamides, PA6T/66 and PA6T/610, were synthesized by high temperature and high pressure solution polycondensation method, and their thermal degradation processes and kinetic mechanisms were analyzed in depth. Firstly, the structure and composition of both were characterized by Fourier transform infrared spectroscopy (FTIR) and hydrogen nuclear magnetic resonance spectroscopy (¹H NMR). The results showed that copolyamide was synthesized successfully. Thermogravimetric analysis (TGA) and thermogravimetric infrared comprehensive analysis (TG-IR) were used to analyze the heat resistance and degradation products of the two copolyamides PA6T. The results of TGA showed that the initial decomposition temperature of the two copolyamides was about 400°C, and the temperature of PA6T/610 was slightly higher. TG-IR results showed that both copolyamides maintained good thermal stability before 350°C, without the generation of degradation products and their corresponding obvious characteristic absorption peaks. Thermal decomposition products increased significantly at about 400°C, and gradually became complete after 450°C. By comparing the Kissinger method, Flynn-Wall-Ozawa method (FWO), and Coats-Redfern method (CR), the thermal degradation activation energy and kinetic reaction mechanism of the two copolyamides were obtained.