Study on reaction kinetics of bio-based semi-aromatic high-temperature polyamide PA5T/56

In this paper, the polycondensation kinetics of bio-based semi-aromatic high-temperature polyamide PA5T/56 was studied in a micro-high-temperature and high-pressure reactor. The polycondensation experiment of PA5T/56 salt solution with temperature of 240-300 celcius and initial water content of 5-30wt% was carried out. The change of end group content in the reaction process was investigated, and the relationship between polymer equilibrium molecular weight and temperature and water content was explored. The results showed that the end group concentration decreased rapidly at the beginning of the reaction and approached equilibrium after a period of time, and the higher the temperature, the higher the initial water content and the lower the equilibrium molecular weight, indicating that the polycondensation of PA5T/56 was an exothermic reaction; on this basis, a kinetics model of polycondensation reaction was established based on the literature model, it was considered that the polycondensation reaction is an acid-catalyzed third-order reaction, and the effects of temperature and water content on the equilibrium and rate of polycondensation reaction can be investigated. The kinetics model of polycondensation reaction was obtained, and the calculated results of the model were basically consistent with the experimental values.