烷基咪唑螯合硼离子液体的合成及摩擦学性能

Imidazolium-bis(salicylato) borate Ionic Liquids as Lubricant Additives:the Effect of Alkyl Chain Lengths on the Tribological Performance

以1种环境友好的双水杨酸螯合硼为阴离子中心,以咪唑环为阳离子骨架,合成了7种新的具有不同烷基直链的螯合硼离子液体D-C_nImBScB(n=4,6,8,10)和C_nImC8BScB(n=4,6,10).利用核磁共振波谱(~1H NMR)、热重分析(TGA)和差示扫描热量(DSC)等技术对7种双咪唑螯合硼离子液体进行了结构和热稳定性分析.以聚乙二醇(PEG200)作为基础油,双边咪唑螯合硼离子液体D-C_nImBScB(n=4,6,8,10)和C_nImC8BScB(n=4,6,10)作为添加剂,采用四球摩擦磨损试验机、扫描电子显微镜(SEM)和能量色散X射线光谱仪(EDX)分别对油样的抗磨减摩性能、磨斑形貌和磨斑表面元素分布进行了分析表征.结果表明,D-C_nImBScB(n=4,6,8,10)和C_nImC_8BScB(n=4,6,10)可用作在较宽温度范围使用的润滑油添加剂,添加C_6ImC_8BScB的PEG200油样抗磨效果最佳,其磨斑直径为0.712 mm,与PEG200相比降低了27.49%,通过适当调节阳离子咪唑环骨架上的双边烷基链长度可以调控离子液体的摩擦学性能.

Seven environmental-friendly ionic liquids containing chelated organoborate anions having different alkyl chain lengths were synthesized and then evaluated as potential lubricant additives.The ~1H NMR,TGA and DSC were employed to characterized the structure and thermal properties of synthesized ionic liquids.The tribo-performacne were systematically studied by four-ball machine and SEM-EDX as well.The synthesized ionic liquids were found to be quite stable at room temperature and showed remarkable improvement in the anti-wear properties of the poly（ethylene） glycol（PEG200） lube base.The results showed that ionic liquids as additives significantly reduced the wear of PEG200,and particularly the variation in substituted alkyl chain length on the imidazolium ring monitored the degree of reduction in wear.C_6ImC_8BScB shows the excellent friction reducing properties among all the synthesized ionic liquids,the coefficient of wear scar diameter lubricated by PEG under 392 N corresponding reduced with mass fraction of 27.49%.