Film Forming Mechanism of Thermoreversible Supramolecular Gel Lubricant for Elastohydrodynamic Lubrication

Mechanical components such as bearings and gears that are in an elastofluidic lubrication condition during smooth operation which were widely used in daily machinery and equipment operation. Therefore, the close examination of the lubrication performance was necessary for thermoreversible supramolecular gel lubricants under elastofluidic lubrication condition. The tribological characteristics of thermoreversible supramolecular gel lubricants with temperature-responsive properties under elastofluidic conditions were predominantly studied in this manuscript. When heated, the supramolecular gel lubricant transformed from a gel to a flowing sol and returns to a gel state when cooled. The thermal stability of thermoreversible supramolecular gel lubricants were determined using synchronous thermal analyzers (TGAs) and differential scanning calorimeters (DSCs). The gel lubricantswere thermally stable, as shown by the sol-gel transition temperature and thermal decomposition temperature values for thermoreversible supramolecular gel lubricants compared with base oils (500SN). The rheological properties of thermoreversible supramolecular gels under different shear stress and temperature were characterized by Rheometer (Anton Paar MCR302) .The results showed that the thermoreversible supramolecular gellubricants demonstrated good mechanical, thermal stability and thixotropy. As the shear force increased, the viscosity of thermoreversible supramolecular gel lubricants decreased, releasing the lubricants bound in the three-dimensional network structure and bringing the shear rate back to the original state to prevent creeping or leaking of the lubricants. A photoelastic flow lubricant meter was used to investigate the actions of speed, load of frictional conditions and glue-forming concentration on the oil film formation mechanism of the thermoreversible supramolecular gel lubricants under elastofluid lubrication condition. According to the results, the oil film thickness of thermoreversible supramolecular gel lubricants increased with increasing speed and decreased with increasing load, and the oil spent time increased as load of operation condition and concentration of thermoreversible supramolecular gels increased on the conditions of elastic flow lubrication. Compared with lithium grease, gels have more consistent film thickness and faster drain times. Stribeck curves of thermoreversible supramolecular gel lubricants were measured by MTM2 microtraction tester. The findings indicated that the friction coefficient of Stribeck curves for thermoreversible supramolecular gel lubricants increased with increasing load and slip-roll ratio. But the friction coefficient of thermoreversible supramolecular gel lubricants decreased with temperature increase. Research showed that the thermoreversible supramolecular gel as a novel type of lubricant with potential application value was demonstrated to have greater tribological performance than base oil and lithium grease.