Effect of Atomic Oxygen Exposure on Polyhedral Oligomeric Silsesquioxane/Polyimide Hybrid Materials in Low Earth Orbit Environment
A novel polyimide (PI) hybrid nanocomposite containing polyhedral oligomeric silsesquioxane (POSS) had been prepared by copolymerization of octa(aminophenyl)silsesquioxane (OAP-POSS), 4,4’ -oxydianiline (ODA), and pyromellitic dianhydride (PMDA). The AO resistance of these POSS/PI hybrid films was tested in the ground-based AO simulation facility. Exposed and unexposed surfaces have been characterized by X-ray photoelectron spectroscopy and FTIR. The XPS data indicate that the carbon content of the near-surface region is decreased from 63.6 to 19.3 at% after AO exposure. The oxygen and silicon concentrations in the near-surface region increase after AO exposure. The data reveal the formation of a passive inorganic SiO2 layer on the POSS/PI hybrid films during the AO exposure, which serves as a protective barrier preventing further degradation of the underlying polymer with increased exposure to the AO flux. SEM images showed that the surface of the 10 wt% POSS/PI became much less rough than that of the pristine polyimide. The AO resistance of the POSS/PI hybrid films is up to several tenfold than that of the pristine polyimide.
Yiwang Bao, Danyu Jiang, Li Tian and Jianghong Gong
S. W. Duo et al., "Effect of Atomic Oxygen Exposure on Polyhedral Oligomeric Silsesquioxane/Polyimide Hybrid Materials in Low Earth Orbit Environment", Key Engineering Materials, Vol. 492, pp. 521-524, 2012