Abstract

Esters of linear long-chain unsaturated fatty acids with a variety of alcohols, both linear and branched, are extensively used in the lubricant industry. Extending the generally accepted principle that disruptions to linearity may favorably enhance tribological properties, this article presents a combined experimental and molecular dynamic simulation study to explore the influence of polar ring strain-inducing heterocyclic moieties on the lubrication behavior of such long-chain unsaturated fatty acid esters. The introduction of these disruptive structural features has been achieved by synthesizing the smallest possible three-membered heterocyclic rings (epoxy and thiirane) containing oxygen and sulfur, respectively, in the backbone of oleic acid esters, creating hitherto unexplored derivatives of such esters. The epoxy ester (EE) and thiirane ester (TE) show significant reduction in friction (40%) and wear (30%) with respect to the linear ester (LE), including in elliptical contact experiments at different interfacial contact stresses. Molecular dynamic simulation studies offer valuable insights into the orientation, adsorption, and diffusion behavior of such atomic changes on the lubricant’s physicochemical and tribological characteristics.

摘要

直链长链不饱和脂肪酸与多种直链和支链醇的酯广泛用于润滑剂行业。本文扩展了普遍接受的原则，即破坏线性可以有利地提高摩擦学性能，本文提出了一项结合实验和分子动力学模拟的研究，以探讨诱导极性环应变的杂环部分对此类长链不饱和脂肪酸的润滑行为的影响酯类。这些破坏性结构特征的引入是通过在油酸酯的主链中合成最小可能的三元杂环（环氧基和硫杂环）（环氧和硫杂环）来实现的，这些杂环分别包含在油酸酯的主链中，从而产生迄今为止尚未开发的此类酯衍生物。与线性酯 (LE) 相比，环氧酯 (EE) 和硫杂丙环酯 (TE) 的摩擦 (40%) 和磨损 (30%) 显着降低，包括在不同界面接触应力下的椭圆接触实验中。分子动力学模拟研究为此类原子变化对润滑剂物理化学和摩擦学特性的取向、吸附和扩散行为提供了宝贵的见解。