Pyrolysis kinetics of polysulfonamide fiber used for fire protective clothing

Polysulfonamide (PSA) fibers, which belong to the series of phenylene terephthalamide fibers, exhibit excellent thermal stability, flame retardancy, and heat resistance. In this work, the thermal behavior of PSA fibers was investigated under nitrogen atmosphere in a thermogravimetric analyzer at heating rates of 5, 10, 15, and 20℃/min from room temperature to 900℃. The activation energy and the kinetics model for PSA fiber pyrolysis have been estimated by using the Friedman method, Flynn–Wall–Ozawa method, and Coats–Redfern method. The appropriate thermal degradation kinetics model for PSA fiber followed a mechanism of one-dimensional diffusion and was determined by the Coats–Redfern method. Kinetic constants and a pyrolysis mechanism model for PSA degradation in a nitrogen atmosphere, which were obtained by model-fitting and model-free methods and were not available in the literature, provide useful information for flame-retardant clothing researchers.