Measurement and Simulation of Thermal Stability of Poly(Lactic Acid) by Thermogravimetric Analysis

The thermal degradation of poly(lactic acid) (PLA) biopolymer was studied as used by the thermogravimetry analyzer in a nitrogen atmosphere in the temperature range of 100–500°C. The reaction was found under these experimental conditions to be of first order with an activation energy of 94.0 and 105.3 kJ/mole and pre-exponential factor 6.43×105 and 1.91×106 1/s, respectively. Slight differences have been found in activation energy depending on the analytical methods used and reported in other previous articles. It was found that the activation energy of thermal degradation increased with increasing the molecular weight of PLA. Moreover, the behaviors involved in the thermal degradation of PLA in nitrogen atmosphere were studied by using the numerical simulation of the kinetic model to dynamical thermogravimetric data. The maximum decomposition temperature, shape index for dynamic condition and life, and degree of decomposition for the isothermal condition of thermal behavior of PLA are predicted via mathematical simulation in this study.