Kinetic study on aircraft-used polymethyl methacrylate under different oxygen concentration

The decompositions of aircraft-used polymethyl methacrylate are studied by means of thermogravimetric analysis and differential thermal analysis. Four kinds of oxygen concentrations are used (5%, 10%, 15%, 21%) and heating rates used vary from 15°C/min to 30°C/min. Improved Coats-Redfern method is used to determine the kinetic parameters and Doyle method was used to calculate the decomposition data. The active energy and pre-exponential factor both increase when the oxygen concentration decreases. The active energy is in the range 100-108 kJ/mol and 87-92 kJ/mol at the two heating rates when oxygen concentration decreases, while the pre-exponential factor is in the range (7-35) × 10⁶/s and (0.4-1) × 10⁶/s. The simulation of weight loss process accords with the real weight loss process well.