A Mechanistic Study of Organic Friction Modifiers Combining Advanced X-ray Analysis with Tribotesting

Organic Friction Modifiers are lubricant additives known for their friction-reducing properties in the boundary lubrication regime by forming adsorbed layers on rubbing surfaces. The exact operation mechanism is still undiscovered, despite more than 100 years of OFM use in lubricant formulations. Nowadays, OFMs attract attention as an alternative to additives containing elements harmful to the environment, like sulphur or phosphorus.
This project investigates the structure of selected OFMs (glycerol monooleate, technical glycerol monooleate and Ethomeen 1812) in the model base oil via synchrotron X-ray scattering techniques and compares these results with the MTM tribometer friction tests. Model formulations were also measured after the addition of water or acetic acid to understand the influence of small polar molecules on the self-assembly and tribological performance of OFM-containing lubricants.
The friction-related phenomena (shear, temperature and pressure) were studied separately in available and custom-built cells to allow for better control of conditions and to understand what is the key phenomenon of friction.
This study reveals the role of OFM in lubricants and important factors affecting their performance.