Molecular dynamics simulation of the effects of base oils in barium-based greases on tribological properties based on IR and GC/MS data

Twelve kinds of base oils were characterized by a series of analytical methods to obtain detailed composition and structure information. Mineral oil and poly alpha olefin oil were mainly composed of long-chain alkanes, while ester oil was mainly composed of ester compounds. Ten of the 12 base oils were selected to synthesize barium lubricating greases . Both base oils and greases were evaluated by molecular simulation , and the corresponding molecular models were constructed based on the structural information of base oils. Grease models constructed by barium 12-hydroxystearate and ester oil exhibited the largest surface adsorption energy and intermolecular interaction energy, respectively, because polar groups in lubricant tend to adsorb on metal surface and form an absorbing film. Comparing physicochemical properties of the synthesized barium lubricating greases. The temperature resistance of grease presents a positive correlation with the simulated intermolecular interaction energy.