Abstract:

In order to investigate the thermal degradation kinetics of poly(1,3,4-oxadiazole) (POD) fibers, thermal degradation performance of POD fibers at certain heating rates in different atmospheres of nitrogen gas and air  were analyzed thermogravimetry. Thermal degradation kinetic parameters of POD fibers were obtained according by Kissinger, Flynn-Wall-Ozawa and Coats-Redfern methods. The result show that the average activation energy of POD fibers in nitrogen gas atmosphere obtained by the Flynn-Wall-Ozawa method  is 276 kJ/mol, and the average active energy of POD fibers at the maximum thermal degradation rate obtained by Kissinger method is of 277 kJ/mol. And in air atmosphere, the thermal activation activation energy of POD fibers is 257.5 kJ/mol at the first stage, and gradually decreases from 195.3 kJ/mol to 79.1 kJ/mol at the second stage. By the combination of Flynn-Wall-Ozawa method and the Coats-Redfern method, the  integral form of the mechanism equation of thermal degradation of POD fibers is obtained, which is random nucleation followed by growth, and only the order of reaction is different.

Key words: oly(1,3,4-oxadiazole) fiber, thermal degradation, kinetics,  thermogravimetry analysis