原子氧环境中聚酰亚胺的质量变化和侵蚀机制

Mass change and erosion mechanism of the polyimide film during atomic oxygen exposure

用石英晶体微天平(QCM)原位监测并研究了聚酰亚胺薄膜在地面原子氧模拟装置中暴露时的质量变化.结果表明,聚酰亚胺薄膜在较低的原子氧束流通量暴露的初期,试样的质量先增加后降低,质量的降低与暴露的时间成正比.在高原子氧束流通量暴露的初期,试样质量的增加不明显,甚至一开始就发生稳态氧化失重.实验数据拟合的结果表明,原子氧对聚合物造成的侵蚀主要发生在有氧原子吸附的表面.质量的增加是由于较低的原子氧通量没有能完全氧化聚合物的表面.原子氧对聚合物材料的侵蚀机制服从Langmuir吸附理论.

The variations of mass changes of polyimide films during exposure in different flux ofatomic oxygen （AO） beams which was a ground-simulated low earth orbit （LEO） space environment, were in-situ studied using QCM. The results show that the mass of the polyimide film increases at the initial stage of the erosion under the condition of low AO flux, subsequently begins to decrease linearly. However, under the condition of high AO flux, the polyimide film shows a steady-state mass loss in the whole exposure process. The computer simulation based on Langmuir adsorption theory suggests that the major reaction path of carrying the mass away from the surface occurs at the oxidized surface. The mass gain results from AO adsorption under an insufficient AO flux on the un-oxidized surface.