Comparative thermal decomposition kinetic analysis of the biodegradable terpolymer poly(lactide-co-propylene carbonate) applied by various theoretical models

The thermal stability and non-isothermal decomposition kinetics of the terpolymer poly (lactide-co-propylene carbonate) (PLAPC) were studied by thermogravimetric and derivative thermogravimetric analyses with multiple heating rates (2.5, 5, 10, 20 °C min−1) under nitrogen gas atmosphere. The microstructure and molecule thermal transition property of PLAPC were examined by 1H NMR, FTIR and differential scanning calorimetry (DSC) respectively. The decomposition kinetic parameters of PLAPC were calculated using ''model-free'' integral method (Flynn-Wall-Ozawa), ''model-free'' differential method (Kissinger) and ''model-fitting'' method (Tang). Its average activation energy thus obtained with different methods ranges from 96.62 to 104.91 kJ mol−1 12 kinetic models were employed to check the most probable decomposition mechanism. The results showed R2 model, F1 (A1) model and R3 model are the most probable to fit the decomposition mechanism.