双咪唑离子液体的合成及其高温摩擦学性能研究

Tribological Properties of Dicationic Imidazolium Ionic Liquids at High Temperature

合成了3种不同连接链的双咪唑离子液体;采用核磁共振谱仪表征了其结构,采用SRV-IV型摩擦磨损试验机评价了其在变温及250℃恒温下的摩擦学性能;并采用扫描电镜(SEM)和X射线光电子能谱仪(XPS)分析了磨斑表面形貌和主要元素的化学状态.结果显示:同变温摩擦磨损试验相比,恒温摩擦磨损试验能更为有效地体现不同双咪唑离子液体的高温摩擦学性能差异;与此同时,烷基链连接的双咪唑离子液体的减摩抗磨性能明显优于醚链连接的双咪唑离子液体,且缩短双咪唑离子液体的连接链长度有利于提高其摩擦学性能.

Three kinds of dicationic imidazolium ionic liquids（ILs） linked with different carbon chains were synthesized.An SRV-IV type friction and wear tester was performed to evaluate the tribological properties of as-synthesized ILs at elevated temperatures from 50 ℃ to 350 ℃ and at a constant temperature of 250 ℃.The morphology and elemental composition of the wear scars were analyzed by means of scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）.Results indicate that,as compared with the friction and wear test at varied temperatures,the tests at a constant temperature of 250 ℃ are more effective in differentiating the tribological properties of dicationic imidazolium ILs at elevated temperatures.In the meantime,the dicationic imidazolium ILs linked with alkyl bridge possessed better friction-reducing and anti-wear abilities than those linked with polyethylene glycol,and decreasing length of the alkyl linking chain of the dicationic ILs can improve their tribological properties.