Tribological behavior of lubricant-impregnated porous polyimide
Abstract Porous materials impregnated with lubricants can be used in conditions where limited lubricant is desirable. In this work, three porous polyimides (PPI) with different densities were prepared. Polyalphaolefin (PAO) impregnated PPI (iPPI) discs were rubbed against steel and sapphire balls. I...
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Tsinghua University Press
2023-12-01
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| Series: | Friction |
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| Online Access: | https://doi.org/10.1007/s40544-023-0796-9 |
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| author | Jinbang Li Ningning Zhou Janet S. S. Wong |
| author_facet | Jinbang Li Ningning Zhou Janet S. S. Wong |
| author_sort | Jinbang Li |
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| description | Abstract Porous materials impregnated with lubricants can be used in conditions where limited lubricant is desirable. In this work, three porous polyimides (PPI) with different densities were prepared. Polyalphaolefin (PAO) impregnated PPI (iPPI) discs were rubbed against steel and sapphire balls. In operando observations of the iPPI–sapphire contacts show that oil is released under an applied load, forming a meniscus around contacts. Cavitation at the outlet is created at high sliding speeds. The amount of released oil increases with increasing PPI porosity. Contact moduli, E*, estimated based on the actual contact size show that trapped oil in iPPIs contributes to load support. At higher speeds, tribological rehydration of the contact occurs in low density iPPI, with that E* rises with speed. For high density PPIs, high speeds give a constantly high E* which is limited by the viscoelastic properties of the PPI network and possibly the rate of oil exudation. Friction of iPPI–steel contacts is governed by the mechanical properties of the PPI, the flow of the lubricant, and the roughness of the PPI surfaces. For low- and medium- density (highly porous, high roughness) PPIs, large amount of oil is released, and lubrication is mainly via lubricant restricted in the contact in the pores and possibly tribological rehydration. For high density (low porosity) PPI, with lower roughness, hydrodynamic lubrication is achieved which gives the lowest friction. Our results show that polymeric porous materials for effective lubrication require the optimization of its surface roughness, stiffness, oil flow, and oil retentions. |
| format | Article |
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| institution | Kabale University |
| issn | 2223-7690 2223-7704 |
| language | English |
| publishDate | 2023-12-01 |
| publisher | Tsinghua University Press |
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| series | Friction |
| spelling | doaj-art-8e4426fe5a8a475e8a50073b79227a0d2025-08-20T03:37:17ZengTsinghua University PressFriction2223-76902223-77042023-12-0112471172510.1007/s40544-023-0796-9Tribological behavior of lubricant-impregnated porous polyimideJinbang Li0Ningning Zhou1Janet S. S. Wong2School of Mechanical Engineering and Mechanics, Ningbo UniversityBeijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms, Beijing Institute of Control EngineeringDepartment of Mechanical Engineering, Imperial College LondonAbstract Porous materials impregnated with lubricants can be used in conditions where limited lubricant is desirable. In this work, three porous polyimides (PPI) with different densities were prepared. Polyalphaolefin (PAO) impregnated PPI (iPPI) discs were rubbed against steel and sapphire balls. In operando observations of the iPPI–sapphire contacts show that oil is released under an applied load, forming a meniscus around contacts. Cavitation at the outlet is created at high sliding speeds. The amount of released oil increases with increasing PPI porosity. Contact moduli, E*, estimated based on the actual contact size show that trapped oil in iPPIs contributes to load support. At higher speeds, tribological rehydration of the contact occurs in low density iPPI, with that E* rises with speed. For high density PPIs, high speeds give a constantly high E* which is limited by the viscoelastic properties of the PPI network and possibly the rate of oil exudation. Friction of iPPI–steel contacts is governed by the mechanical properties of the PPI, the flow of the lubricant, and the roughness of the PPI surfaces. For low- and medium- density (highly porous, high roughness) PPIs, large amount of oil is released, and lubrication is mainly via lubricant restricted in the contact in the pores and possibly tribological rehydration. For high density (low porosity) PPI, with lower roughness, hydrodynamic lubrication is achieved which gives the lowest friction. Our results show that polymeric porous materials for effective lubrication require the optimization of its surface roughness, stiffness, oil flow, and oil retentions.https://doi.org/10.1007/s40544-023-0796-9polyimideporous materialfriction mechanismpolymerlimited lubrication |
| spellingShingle | Jinbang Li Ningning Zhou Janet S. S. Wong Tribological behavior of lubricant-impregnated porous polyimide Friction polyimide porous material friction mechanism polymer limited lubrication |
| title | Tribological behavior of lubricant-impregnated porous polyimide |
| title_full | Tribological behavior of lubricant-impregnated porous polyimide |
| title_fullStr | Tribological behavior of lubricant-impregnated porous polyimide |
| title_full_unstemmed | Tribological behavior of lubricant-impregnated porous polyimide |
| title_short | Tribological behavior of lubricant-impregnated porous polyimide |
| title_sort | tribological behavior of lubricant impregnated porous polyimide |
| topic | polyimide porous material friction mechanism polymer limited lubrication |
| url | https://doi.org/10.1007/s40544-023-0796-9 |
| work_keys_str_mv | AT jinbangli tribologicalbehavioroflubricantimpregnatedporouspolyimide AT ningningzhou tribologicalbehavioroflubricantimpregnatedporouspolyimide AT janetsswong tribologicalbehavioroflubricantimpregnatedporouspolyimide |