Kinetics and evolved gas analysis of the thermo-oxidative decomposition for neat PPS fiber and nano Ti–SiO2 modified PPS fiber

Abstract

Using isoconversional methods and model-fitting methods, the non-isothermal thermo-oxidative decomposition kinetics of the nano Ti–SiO2 modified PPS fiber (AO-PPS) and neat PPS fiber are investigated. Decomposition processes of both PPS fibers can be differentiated into two stages with totally different mechanisms. Using the Málek method combined with residual sum of squares, the most probable mechanism model of the first stage is derived, which belongs to the deceleration α-t curve and the integral form is g(α) = (1-α)−1-1. Thermo-oxidative decomposition processes of the second stage are the aggregation of many complicated reactions, which cannot be expressed through the simple, single kinetic mechanism. Evolved gas analysis of both PPS fibers gives an insight of the mechanism of the thermo-oxidative decomposition processes. The main reactions of the first stage involve the breaking of the phenyl-S bonds and the cross-linking of remaining molecules. The multiple complex reactions in the second stage verify the kinetic analysis of the mechanisms.