Abstract: Amide soap-based grease exhibits excellent properties such as high-temperature stability, oxidation stability, mechanical stability, radiation resistance, and long service life. To investigate the influence of molecular structure of amide soap-based thickeners on grease performance, four types of N-octadecyl terephthalamate metal salt thickeners and four sodium-based N-alkyl terephthalamate thickeners with varying hydrocarbon chain lengths were synthesized, and corresponding greases were prepared. The grease properties including penetration, dropping point, oil separation rate, and tribological performance were evaluated to explore the relationship between the molecular structure of amide soap-based thickeners and grease characteristics. Results indicate that the performance of amide soap-based grease demonstrates regular variations with changes in the atomic number of metal ions and hydrocarbon chain length. A soap-soap dimer model was established using molecular simulation methods to preliminarily discuss the influence mechanism of thickener molecular structure on grease properties.

Key words: amide soap, lubricating grease, thickener, constitutive relationship, molecular simulation