Synergistic effect of space radiation environments on the mechanical properties of polyimide films

Polyimide film had been widely used on the spacecraft as thermal control material or structural materials. During in mission, polyimide film will be damaged by space radiation environments such as energetic charged particles and solar electromagnetic radiation, especially electron, proton and ultraviolet, which will lead to the degradation of its mechanical properties or structural rupture. In this paper, the mechanical properties of polyimide film under the synergistic effect of electron, proton and near ultraviolet was tested by the space integrated irradiation test facility in Beijing Institute of Spacecraft Environment Engineering, and the tensile strength and rupture elongation of it was studied. Under the synergistic effect of ultraviolet, electron and proton, the mechanical properties decrease in the early stage of irradiation larger than in the electron and proton irradiation, but less than in the degradation of mechanical properties caused by electrons and protons in the later stage of irradiation. During the initial stage of synergistic irradiation of electron, proton and near ultraviolet, the degradation law of mechanical properties of polyimide films is basically consistent with that under electron or proton irradiation. But its tensile strength and rupture elongation will exponentially increase with space combined radiation until tend to stable.