State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
ACS Appl Mater Interfaces. 2010 Mar;2(3):870-6. doi: 10.1021/am900847j.
Three imidazolium-based ionic liquids containing sterically hindered phenol groups were synthesized. The cation was 1-(3,5-ditert-butyl-4-hydroxybenzyl)-3-methyl-imidazolium, and the anions were tetrafluoroborates, hexafluorophosphates, and bis(trifluoromethylsulfonyl)imide. The physical properties of the synthetic products and of poly(ethylene glycol) (PEG) with the additive were evaluated. The oxidative stability of 0.5 wt % 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-methyl-imidazolium hexafluorophosphates in PEG were assessed via rotating bomb oxidation test (RBOT), thermal analysis, and copper strip test. The tribological behaviors of the additives for PEG application in steel/steel contacts were evaluated on an Optimol SRV-IV oscillating reciprocating friction and wear tester as well as on MRS-1J four-ball testers. The worn steel surface was analyzed by a JSM-5600LV scanning electron microscope and a PHI-5702 multifunctional X-ray photoelectron spectrometer. RBOT test, thermal analysis, and copper strip test results revealed that synthesized ionic liquids possessed excellent antioxidant properties. Tribological application results revealed that these could effectively reduce friction and wear of sliding pairs compared with the PEG films used without the additives. Specifically, (BHT-1)MIMPF(6) exhibited better antiwear properties at an optimum concentration of 1 wt %. At this level, its antiwear property significantly improved by 100 times with respect to using just the PEG base oil. Boundary lubrication films composed of metal fluorides, organic fluorines, organic phosphines, and nitride compounds were formed on the worn surface, which resulted in excellent friction reduction and antiwear performance.
合成了三种含有位阻酚基团的咪唑鎓基离子液体。阳离子为 1-(3,5-二叔丁基-4-羟基苄基)-3-甲基-咪唑，阴离子为四氟硼酸根、六氟磷酸根和双(三氟甲基磺酰基)亚胺。评估了合成产物以及添加添加剂的聚乙二醇（PEG）的物理性能。通过旋转弹氧化试验（RBOT）、热分析和铜带试验评估了 0.5wt%1-(3,5-二叔丁基-4-羟基苄基)-3-甲基-咪唑六氟磷酸酯在 PEG 中的氧化稳定性。在 Optimol SRV-IV 振荡往复摩擦磨损试验机和 MRS-1J 四球试验机上评估了添加剂在钢/钢接触中的 PEG 应用的摩擦学性能。使用 JSM-5600LV 扫描电子显微镜和 PHI-5702 多功能 X 射线光电子能谱仪分析磨损的钢表面。RBOT 试验、热分析和铜带试验结果表明，合成的离子液体具有优异的抗氧化性能。摩擦学应用结果表明，与未添加添加剂的 PEG 薄膜相比，这些离子液体能有效降低滑动副的摩擦和磨损。特别是，（BHT-1）MIMPF(6)在最佳浓度 1wt%时表现出更好的抗磨性能。在该浓度下，其抗磨性能相对于仅使用 PEG 基础油提高了 100 倍。在磨损表面形成了由金属氟化物、有机氟、有机膦和氮化物组成的边界润滑膜，从而具有优异的减摩和抗磨性能。
