Tribological properties of the polyacrylate/PTFE coating modified by POSS in the space environment |
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Authors: | Chuanyong Yu Pengfei Ju Hongqi Wan Lei Chen Hongxuan Li Huidi Zhou Jianmin Chen |
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Affiliation: | 1. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 China Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049 China;2. Shanghai Aerospace Equipment Manufacture, Shanghai, 200245 China;3. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 China |
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Abstract: | The irradiation conditions in the low earth orbit (LEO) severely inhibit the development of polymeric materials for solid lubrication coatings used on the external surfaces of spacecraft. To solve the problem, octavinyl polyhedral oligomeric silsesquioxanes (OvPOSS) were covalently grafted onto poly(methyl/butyl methacrylate) composites (PMB). The results showed that the appropriate incorporation of OvPOSS (10 wt %) significantly reduced the friction coefficient and improved the wear resistance of the OvPOSS/PMB composite coatings. Furthermore, the impact of OvPOSS on the tribological properties of PMB/polytetrafluoroethylene (PTFE) lubrication coatings in the space environment was investigated. In particular, the degradations, mass losses, surface morphologies, and chemical compositions of POSS/PMB/PTEF composite coatings were characterized under ultraviolet (UV), electric irradiation (EI), and atomic oxygen (AO). The results indicated that OvPOSS provides numerous Si O Si bonds in the polymer matrix that improve the resistance to UV and EI. Besides, a passivating SiO2 layer was formed to prevent further erosion and degradation of the underlying PMB and PTFE components during AO irradiation. Particularly, the wear resistance of OvPOSS/PMB/PTFE coatings under AO irradiation increased significantly compared with the pristine PMB/PTFE coating. Overall, our results indicate that POSS-containing composites are a good prospective material for space application in the LEO. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48730. |
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Keywords: | coatings composites friction irradiation wear and lubrication |
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