Thermal Degradation Kinetics of PS and PMMA

In this work, the thermal degradation (pyrolysis) kinetic of polymers was studied. Attention was focused on the thermal pyrolysis of polymethylmethacrylate (PMMA) and polystyrene (PS) as two thermoplastic polymers. Thermogravimetric (TG) analysis is a basic method for kinetic analysis calculations. Different analytical methods such as Flynn-Wall-Ozawa, Friedman, Kissinger and Coats-Redfern were used to determine the triplet kinetic parameters. Consequently the best kinetics model for two polymers was proposed and the simulated kinetics curves based on the determined kinetics parameters were compared to the experimental TG curves. Investigation on thermal degradation of polystyrene shows that random chain scission, unzipping and intermolecular transition reactions are the most dominant mechanisms. Thermal degradation of PMMA progresses at different steps in which the most unstable step, initiates with head to head bounds cleavage.