Kinetic analysis of thermal decomposition of poly(propylene carbonate)

The dynamic thermal degradation of poly(propylene carbonate)s (PPC)s with alternating molecular structure and varying molecular weights was studied using TG-DTA. Because of the thermal hysteresis and the dissolved air for bulk samples, it is beneficial to employ film samples for kinetic analysis. It was found that the DTA curve for low molecular weight PPC had both an endothermic peak and an exothermic peak, whilst the DTA curve for high molecular weight PPC exhibited only the exothermic peak. PPC with high molecular weight showed better thermal stability than that with low molecular weight. Kinetic analysis of the dynamic TG curves for PPCs with varying molecular weights was carried out using the Ozawa method. The decomposition activation energy of PPC was calculated to range from 105 to 118 kJ/mol. The influence of nitrogen flow rate on the decomposition of PPC was also investigated and is discussed.