The purpose of this work is to understand the mechanisms of high temperature decomposition for a ceramic coated polyimide (DP-29) composite by developing a model for each of the mechanisms. The model covers a temperature range of 340-380°C, an oxygen range of 0-21%, and a duration of 100 hours.
An oven reactor was used to obtain experimental data for the thermal and thermo- oxidative decomposition reactions of the polyimide composite. The data taken was used to develop a model of the decomposition process. The equation of continuity for oxygen was used to find the concentration profile of oxygen through the ceramic film. The solution to the equation of continuity was combined with the model of polyimide decomposition to form an overall model for the prediction of thermo-oxidative mass loss of a ceramic coated polyimide composite.
The kinetic model predicts the decomposition reaction of the polyimide composite to within 10% of the experimental data taken. The overall model shows that temperature has the greatest effect on the rate of decomposition of a ceramic coated polyimide composite. Surface coverage of the ceramic coating on the polyimide composite has the next greatest effect on the decomposition rate and oxygen concentration of the atmosphere has the smallest effect.