Kinetics of Thermal Decomposition of Expanded Plystyrene in Different Gaseous Environments

The characteristics of thermal decomposition of expanded polystyrene (EPS) foams were studied in various gaseous environments, both oxidizing and non-oxidizing, over a narrow range of heating rates between 1 and 30 K/min using non-isothermal thermo gravimetric analysis (TGA). A modified integral-optimization technique was developed for multiple rate-controlling decomposition reactions. Results from kinetic data analysis shows that the activation energy of EPS foam decomposition in air is much less than in non-oxidizing environments, including nitrogen, helium and argon. Qualitative mass spectrometric studies of EPS pyrolysis gases revealed the differences in EPS foam decomposition mechanism between various gaseous environments. Furthermore, it was found that the non-oxidizing gases, especially helium, have a significant effect on the decomposition efficiency of the EPS foam.