This work describes the synthesis of alkyl sulfur‐functionalized polymethacrylate‐based Viscosity Index Improvers (VII) derived from oleic acid (OLA) for mineral paraffinic lubricating oils. In this strategy, OLA was first quantitatively ramified by alkyl thiols containing long aliphatic chains through thiol‐ene coupling as demonstrated by ¹H NMR spectroscopy with the complete consumption of OLA internal double bonds. The resulting alkyl sulfur‐functionalized OLA‐based derivatives were methacrylated through Steglich esterification in order to afford highly suitable hydrophobic OLA‐based monomers which, as far as we know, have not been described yet in the current literature. High polymethacrylate molecular weights were reached through radical polymerization despite the long alkyl pendant chains contained in their backbones. Finally, the resulting alkyl sulfur‐functionalized OLA‐based polymethacrylates have been blended in a mineral paraffinic oil (MPO) of reference at 5 wt% and evaluated as VII. Rheological measurements revealed that polymer thickening powers were significantly improved in oil with temperature and promoted by increasing the pendant alkyl thiol contained in polymer backbones. Moreover, the viscosity index of MPO was significantly improved with the addition of both synthesized homopolymers which confirmed their efficiency as VII. In the meantime, these results have been compared with a previously reported polymer, the poly(2‐[methacryloyloxy]ethyl oleate) (PMAEO), which demonstrated a lower VII efficiency compared with its analogous polymethacrylates containing an additional alkyl chain in their pendant chains.

中文翻译：

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烷基硫官能化油基聚甲基丙烯酸甲酯的合成及其在矿物石蜡润滑油中的粘度指数改进剂的应用

这项工作描述了基于烷基硫官能化的聚甲基丙烯酸酯的粘度指数改进剂（VII）的合成，该改进剂是从油酸（OLA）衍生而来的，用于矿物石蜡润滑油。在这种策略中，OLA首先通过含有长脂肪链的烷基硫醇通过硫醇-烯偶联进行定量分枝，如图^1所示。完全消耗OLA内部双键的1 H NMR光谱。所得的烷基硫官能化的基于OLA的衍生物通过Steglich酯化进行了甲基丙烯酸酯化处理，以提供高度合适的疏水性基于OLA的单体，据我们所知，当前文献中尚未对其进行描述。尽管主链中含有长烷基侧链，但通过自由基聚合仍可达到较高的聚甲基丙烯酸甲酯分子量。最后，将所得的烷基硫官能化的基于OLA的聚甲基丙烯酸酯以5 wt％的比例混入参考的矿物石蜡油（MPO）中，并进行VII评估。流变学测量表明，随着温度的升高，聚合物的增稠能力在油中显着提高，并通过增加聚合物主链中所含的烷基侧基硫醇来促进。此外，通过添加两种合成的均聚物，MPO的粘度指数得到显着提高，这证实了它们作为VII的效率。同时，这些结果已与先前报道的聚合物聚（2- [甲基丙烯酰氧基]乙基油酸酯）（PMAEO）进行了比较，与在其侧链中含有一个额外烷基链的类似聚甲基丙烯酸酯相比，该聚合物的VII效率更低。 。