Study on the interface and morphological control mechanism of calcium sulfonate grease thickener

In this study, lauric acid was introduced in the growth of thickener of calcium sulfonate grease, and the low temperature fluidity and drop point of the grease were greatly improved by regulating the morphology of the thickener and the oil fixing ability of the surface. The aspect ratio of thickener was increased from 1 to 5, and the specific surface area was increased by 40.12%. At the same consistency, the low temperature similar viscosity decreased by 11.63%, and the drop point increased by nearly 100 ℃. By comparing the effects of lauric acid, amine and alcohol with different polar end groups on the surface adsorbability and wettability of the thickener, it was found that the adsorption quality of the three molecules was similar, but only lauric acid and amine could significantly improve the lipophilicity of the surface of the thickener and increase the drop point of the grease by nearly 100 ℃. Through molecular dynamics simulation, it is found that the alkyl chain of linear acid and amine molecules adsorbed on the surface of the thickener is almost perpendicular to the surface of the thickener, which makes the interface base oil difficult to slip, increases the adsorbed oil content and the effective radius of the thickener, and effectively increases the drop point of the grease. The long alkyl chain of the linear chain alcohol molecules is almost parallel to the surface of the thickener, which has little effect on the physicochemical properties of the grease.