Dynamic Bleeding Behavior of Commercial Oil-Impregnated Porous Polymers

AbstractThis study compared the tribological performance of four commercial oil-impregnated porous polymer materials and proposed a new benchmark test to measure their dynamic oil bleeding rate. Results were further evaluated using a half-life model. To reveal the structure-performance relationship, the effects of material properties, surface roughness and porosity on the water contact angle (WCA) were discussed using a combined model based on the Wenzel and Cassie-Baxter equations. Results showed that higher WCAs indicated higher oil content at the interface, which favors better tribological performance. The material with a highly fibrous pore structure demonstrated the best performance, with low friction and temperature as well as the longest half-life. It is suggested that optimizing the fibrous content and pore size can improve the performance and extend the life of oil-impregnated porous polymer. This research provides valuable insights into the evaluation and design of oil-impregnated porous polymer materials for improved tribological performance in various applications.Keywords: Porous polymerlubricationbleeding ratedegradationcontact angle AcknowledgmentsThe Timken Company is thanked for supporting this work. We gratefully acknowledge Ryan D. Evans, Director of The Timken Company R&D Department, for allowing us to publish this paper and commenting on the manuscript. In addition, we are grateful for the discussions with William Hannon, Carl H. Hager, Robert A. Pendergrass, and Matthew R. Boyle at The Timken Company.Disclosure StatementNo potential conflict of interest was reported by the author(s).