环境友好脂肪酸型离子液体的流变学与摩擦学性能

Rheological and Tribological Properties of Environment Friendly Fatty Acid Based Ionic Liquids

为研究不同结构脂肪酸离子液体的流变学及其对润滑油性能的影响,以蓖麻油酸、油酸、二聚酸及胆碱为原料,制备3种环境友好型润滑材料([cho][ricinoleat],[cho][oleat],[cho][dimer]),采用流变仪和SRV摩擦试验机研究其流变学和摩擦学性能,采用扫描电子显微镜(SEM)和X-射线能谱仪(EDS)对磨损表面进行分析,初步探讨其润滑机制。结果表明:制备的[cho][ricinoleate]和[cho][dimer]是离子液体,室温下以液体状态存在,而[cho][oleic acid]室温下是以半固体的形态存在,类似润滑脂;随着温度和剪切速率的变化,[cho][ricinoleate]和[cho][dimer]黏度始终大于150BS基础油,其中[cho][dimer]黏度最大,并具有最优的减摩和抗磨性能,其主要原因可以推测为离子液体在金属表面形成双电层结构的吸附膜,以及离子液体较高的黏度增加了油膜厚度以及承载能力。

In order to study the rheology of fatty acid ionic liquids with different structures and its effect on the properties of lubricating oil,three environmentally friendly lubricants were prepared from ricinoleic acid,oleic acid,dimer acid and choline,including[cho][ricinoleat],[cho][oleat]and[cho][dimer].Their rheological and tribological properties were investigated by Rheometer and SRV.The lubrication mechanism was preliminary explored by analyzing the worn surfaces with SEM/EDS.The results show that both[cho][ricinoleate]and[cho][dimer]are ionic liquids and in liquid state at room temperature,but[cho][oleate]is semisolid and seems like a lubricant grease.The viscosities of[cho][ricinoleate]and[cho][dimer]are always higher than that of 150BS base oil with the changes of temperature and shearing rate.Especially,[cho][dimer]with the highest viscosity shows the optimal friction reducing and anti-wear properties.The probable reason is speculated that[cho][dimer]as an ionic liquid forms an adsorption film with double electric layer,and its highest viscosity increases the lubrication film thickness and loading capacity.