Effect of electron beam irradiation on polyimide film

The effects of electron beam radiation on polyimide films were investigated through dynamic mechanical analysis (DMA), in which the energy of the electron beam was set to a voltage of 1 MeV and a beam current of 4 mA. The β2 sub-glass relaxation temperature of polyimide decreased with irradiation dose, consisting with formation of free radicals at the ends of the molecular chains. The glass relaxation temperatures are not influenced as a function of increasing electron beam exposure because imide rings prevent structural damage by electron beam irradiation. Furthermore, decomposition temperatures of the irradiated polyimide slightly decrease, from 571.42 to 570.67 °C and the residue weight also decreases.