Research on Kapton aerobic pyrolysis by using ReaxFF molecular dynamics simulation

In the oxygen-containing defect of insulation, corona discharge caused high temperature is the main reason for the cleavage of chemical bonds, which would lead the insulation failure. To address the problems, some of ReaxFF simulations are carried out to reveal the aerobic pyrolysis of widely-used insulation Kapton-type polyimide. The effects of temperature and its elevation gradient on the disintegration response and distribution of products are investigated. The result shows that, oxygen connects to polyimide chain without separation at the beginning of reaction. And the rate of temperature increase is able to accelerate destruction of the polymer. CO₂, H₂O and C₂H₂O are dominant products. The quantitative relation between CO₂ and H₂O in simulations of aerobic and non-oxygen models has proved the experimental result that oxygen enriched atmosphere is in favor of deterioration of polymers. The present work demonstrates that by using ReaxFF simulation method, it is able to elucidate detailed chemical reaction in polymer pyrolysis, by which the aging and failure of insulation can be in-depth understood.