Effect of 10 MeV electron irradiation on polyimide composites for space systems

Abstract This paper presents the results from a study on the effect of 10 MeV electron irradiation on polyimide (PI)–tungsten oxide W O 2 composites. The electron flux (fluence rate) was 3.5 × 1 0 15 electrons c m −2 se c −1 . A single absorbed dose varied between 10 − 20 kGy with the maximum total absorbed dose being 10 MGy . The morphological, physicomechanical, and dielectric properties of the samples were studied before and after irradiation with fast electrons, at various accumulated doses. It was found that irradiation with electrons at the maximum dose leads to an increase in the roughness of the PI surface, with an increase in average roughness from 28 to 46 nm, and for the PI/W O 2 composite the roughness is practically unchanged, from 55 nm pre-irradiation to 58 nm post-irradiation. Irradiation of PI with fast electrons increases its Vickers microhardness by 39%, while that of the PI/W O 2 composite decreases by 10% post-irradiation. At a maximum absorbed dose of 10 MGy , the dielectric constant PI decreases by almost 20%, while fast electron irradiation of the PI/W O 2 composite has practically no effect on the dielectric constant.