Abstract：In order to investigate the thermal imidization process of different polymerization systems, the peak temperatures of imidization reaction of three polyimide (PI) systems at different heating rates were obtained by differential scanning calorimetry (DSC) test. The activation energy, pre exponential factor and reaction kinetics equation of different PI were calculated by Kissinger method and Flynn-Wall-Ozawa method. The relationship among the reaction rate, reaction temperature and conversion rate was studied. The flexible structure PI-1 had almost no dissociation reaction, the rigid structure PI-2 and semi-rigid structure PI-3 were accompanied by the production of anhydride in the imidization process. At the same time, the temperature range of the dissociation reaction was determined to be 150-300 ℃ by in-situ temperature rising infrared spectroscopy. Combined with the coupling effect of kinetics and thermodynamics, the results illustrated that the process of imidization of PI with flexible and rigid copolymer structure occur relatively gently, which was an ideal polymerization system for the preparation of high strength and high modulus PI fiber. This work has important reference significance for improving the mechanical properties of PI fibers by adjusting the preparation conditions.
CHEN Xue,CUI Jing,SUN Xuyang et al. Study on Thermal Imidization Process of Polyimide Fiber[J]. Chemical Reaction Engineering and Technology, 2022, 38(4): 338-347.
