Preparation and tribological behavior of high‐temperature oil‐containing porous polyimides

Abstract This paper aimed to attempt the fabrication of high‐temperature oil‐containing porous polyimides (OCPPIs) using as‐polymerized powder with a no processing melting point, as well as investigate its tribological behavior. The OCPPIs were fabricated using a cold‐press sintering technique containing multiple gradient processing steps. Coalescence tightly among polymer powders was successfully achieved under a high‐elastic state by extending holding time vastly based on the time–temperature equivalence principle. The results indicate that OCPPIs possessed a high performance of oil retention after centrifuging in rotation 6000 r/min within 120 min whether low or high porosity. The tribological behaviors were evaluated by reciprocating friction tests under point‐contact conditions. Surprisingly, the tribological properties showed counterintuitive performance, wherein the best performance on the anti‐friction and wear resistance is encountered for the PPIs with the lowest porosity due to the excellent mechanical performance. The corresponding tribological mechanism with respect to multi‐phase wear and liquid–solid lubrication was also discussed comprehensively. This work fills the gap with respect to the fabrication of high‐temperature oil reservoirs and contributes to further understanding the forming mechanisms of porous materials under a high‐elastic state.