Thermal degradation kinetics of poly(1,3,4-oxadiazole) fibers

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 by thermogravimetry. Thermal degradation kinetic parameters of POD fibers were obtained 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 of 276 k J / mol,and the activation energy of POD fibers at the maximum thermal degradation rate obtained by Kissinger method is of 277 k J / mol. And in air atmosphere,the thermal degradation activation energy of POD fibers is 257. 5 k J / mol at the first stage,and gradually decreases from 195. 3 k J / mol to79. 1 k J / mol at the second stage. By the combination of the Flynn-Wall-Ozawa method and the CoatsRedfern 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.