Study On The Atomic Oxygen Effects And Protection Of Kapton Film

Atomic oxygen is the most abundant neutral gas in the atmosphere of low earth orbit.Due to the strong oxidation of atomic oxygen,it could cause oxidation corrosion to spacecraft materials,especially polymer materials.As one of the widely used materials for spacecraft,Kapton films is often used as a reference standard which is for comparison of flight test and ground simulation test of space polymer materials.In this paper,the most representative Kapton films materials are selected,and the mechanism of atomic oxygen effect of Kapton materials is explored from the physical and chemical reactions.The space atomic oxygen evaluation of Kapton/Al₂O₃ composite films prepared by ion exchange method and sol-gel method provides a reference for the practical application of atomic oxygen protective films.Based on the chemical corrosiveness of single atom nitrogen without single atom oxygen,through changing the air source and using the ground simulation equipment of atomic oxygen effect,the atomic oxygen and atomic nitrogen exposure experiments of Kapton films were carried out respectively to explore the contribution of physical etching reaction to the atomic oxygen effect.The results show that the mass loss of Kapton films also occurs under the etching of atomic nitrogen.With the increase of etching time,the unit weight loss rate increases gradually.Among them,the mass loss of samples etched by atomic oxygen for a period of time and then by atomic nitrogen is greater than that of samples not etched by atomic oxygen.This shows that in the initial stage of atomic oxygen effect,the main corrosion is atomic oxygen corrosion.When the chemical reaction between the surface of Kapton material and atomic oxygen leads to the roughening of the films,the etching of atomic nitrogen will accelerate the corrosion of atomic oxygen.In order to further improve the applicability of Kapton films in space environment,Kapton/Al₂O₃ composite films were prepared by ion exchange method and sol-gel method.The optical and mechanical properties of the composite films were analyzed,and the changes of the quality and microstructure of atomic oxygen before and after exposure were also analyzed.The prepared Kapton/Al₂O₃ composite films,exposed to the atomic oxygen environment for a short time,shows good resistance to atomic oxygen corrosion due to the inhibition of the Al₂O₃layer on the diffusion of atomic oxygen.With the increase of exposure time of atomic oxygen,atomic oxygen diffuses into the interior of Kapton matrix through the pores of Al₂O₃layer,resulting in the undercutting effect of the matrix,which leads to the fall of Al₂O₃ layer on the surface,the exposure of Kapton matrix,and the decrease of atomic oxygen resistance.