Abstract: Using dimethyl terephthalate and pyromellitic dianhydride as core structures and octadecylamine as terminal chains, two thickeners including octadecyl terephthalamide (C₁₈DA) and sodium octadecyl terephthalamate (C₁₈DA-COONa)featuring hydrogen bonding and π-π stacking interactions were designed and synthesized. Their molecular structures were confirmed by nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. Subsequently, lubricating greases were prepared using C₁₈DA and C₁₈DA-COONa as thickeners, and their microstructures, lubricating performance, and extreme pressure properties were systematically investigated. Finally, the lubrication mechanisms of these thickeners were elucidated through quantum chemical calculations and molecular dynamics simulations.Compared to C₁₈DA, C₁₈DA-COONa exhibits a higher melting point, enhanced viscosity, and superior thickening efficiency, with a greater tendency to self-assemble into stable three-dimensional network structures within the base oil.Grease formulated with C₁₈DA-COONa demonstrates significantly improved extreme pressure performance.Molecular simulations reveal that C₁₈DA-COONa generates stronger hydrogen-bonding interactions in the base oil system, facilitating the formation of helical nanofibers. This structural arrangement enhances thickening efficacy and imparts superior tribological properties to the lubricant.

Key words: benzoyl derivatives, thickener, self-assembly, lubrication, computational simulation