Degradation and Mechanism of Mechanical Properties of Polyimide Film Irradiated by Gamma Ray

Abstract

Polyimide (PI) films might be damaged under space high energy particle irradiation. In this paper, the mechanical properties and mechanism of polyimide film is studied with the 60Co radiation source, the thermo-gravimetric analysis and the XPS analysis. Significant total dose effect is found in the mechanical properties of the PI film under gamma ray radiation. The tensile strength and rupture elongation of polyimide film increase first and then decrease exponentially with the increase of irradiation dose. The corresponding initial decomposition temperature of the gamma ray-radiated polyimide film changed from 570°C to 590°C for weight-loss ratio of 2%. From XPS analysis, it can be found that there were rupture and crosslink of chemical bond in polyimide film. In early stage of gamma ray radiation, the rupture of C-N bond and following crosslink is for the increase of mechanical properties of polyimide film, and as the increase of radiation, the rupture of C=O and −N(CO)bond, formation of C-N bond, release of N was for the decrease of mechanical properties of polyimide films.