关键词: 复合钛基润滑脂, 制备工艺, 加料顺序, 分子模拟, 反应机理

Abstract: Using the control variable method, the effect of raw material type, ratio and preparation process on the grease-forming effect of the composite titanium-based grease system was systematically investigated, and the synthesis reaction mechanism was explored by molecular simulation method, and the internal principle of the grease-forming effect of the feeding order was revealed from the different reaction energy barrier and charge transfer level.The results show that the preferred thickener preparation raw materials of titanium complex grease are tetrabutyl titanate, stearic acid and terephthalic acid, and the best molar ratio is 1:1:1. The preferred feeding order of the two acid components is to add terephthalic acid first and then stearic acid.The optimized preparation process is: first, tetrabutyl titanate, terephthalic acid and base oil are mixed, heated to 85 ℃reaction for a certain time after adding stearic acid, heated to 190 ℃ for refining, after the completion of refining control rate rapid cooling to about 80 ℃, grinding into grease.The results of molecular simulation show that the energy barriers for the reaction of tetrabutyl titanate with terephthalic acid and stearic acid are 111.89 kJ/mol and 334.69 kJ/mol, respectively, indicating that tetrabutyl titanate is difficult to react directly with stearic acid；After the reaction of tetrabutyl titanate and terephthalic acid, the electron-induced effect of benzene ring significantly increases the positive charge of titanium atoms and enhances the activity of the reaction with stearic acid. At the same time, the two carboxyl groups of dibasic acid contribute to the cross-linking of different titanium soap molecules to form a dense three-dimensional network skeleton structure, which enhances the adsorption and binding ability of base oil and improves the grease-forming effect of the system.

Key words: composite titanium-based grease, preparation process, feeding order, molecular simulation, reaction mechanism