Synthesis of Layered Octadecyltrimethylammonium-Templated Aluminosilicate and Its Use as a Thickening Agent for Lubricating Grease

We describe herein the use of octadecyltrimethylammonium-templated aluminosilicate (designated as LS) as a thickener to induce gelation. LS samples with different aluminum/silicon molar ratios (Al/Si = 0, 0.05, 0.10, 0.15, 0.20) were synthesized hydrothermally and characterized by X-ray diffraction analysis, 27 Al MAS NMR spectra, elemental analysis, and scanning electron microscopy. The aluminum/silicon molar ratio was shown to be an important factor affecting the rheological properties of LS gels. With an increasing Al/Si molar ratio, the viscoelasticity and structural strength of the LS gel were enhanced, the dropping point increased, and the amount of oil separation decreased. LS (0.20) gel exhibited superior relative elastic properties. The strength of the LS (0.20) gel was also enhanced with increasing LS (0.20) content. In SRV tests, LS (0.20) gel with different content showed good performance in terms of load-bearing and anti-wear properties, indicating that LS was strongly adhered on the friction surface, and thereby promoted lubrication. A fair comparison was made between organic montmorillonite gel and LS gel under the same test conditions. Owing to simple preparation and the promising rheological and tribological properties, LS gels hold great potential for application in lubricating grease. Graphical Abstract