膨润土-复合铝基润滑脂的老化分析

Aging analysis of bentonite-composite aluminum base lubricating grease

以环烷油为基础油,以膨润土和复合铝皂为稠化剂制备了膨润土-复合铝基润滑脂(简称膨润土润滑脂),通过紫外模拟老化,利用正交实验确定膨润土润滑脂的适宜配方为:在150℃下添加1.5%(w)抗紫外老化剂UV531。利用FTIR,DSC,TEM等方法研究了膨润土润滑脂在长时间暴露紫外光下,膨润土润滑脂的性能及其内部微观结构的变化。实验结果表明,老化后的膨润土润滑脂的剪切应力均降低,触变环面积基本减小,黏度下降,且形成了局部硬化。老化后的膨润土润滑脂主要生成了含羟基、羰基等的含氧衍生物,使润滑脂内部结构发生改变,稠化剂结构被破坏,稳定性降低。抗紫外老化剂可以降低一些老化对热稳定性的影响。

Bentonite compound aluminum base lubricating grease（abbreviation for bentonite grease） was prepared by using naphthenic oil as base oil and bentonite and composite aluminum soap as thickening agent. Through simulation of aging by ultraviolet,it was determined by the orthogonal experiment that the optimum formulae for bentonite grease was：1.5%（w） anti UV aging agent UV531 was added at 150 ℃ to the grease. The properties of bentonite grease and the changes of its internal microstructure in the long time exposure to ultraviolet light were studied by FTIR,DSC,TEM. The experimental results showed that the shear stress of bentonite grease decreased after aging,the area of thixotropic ring decreased basically,the viscosity decreased,and the local hardening was formed. After aging,the bentonite grease mainly produced oxygen containing derivatives containing hydroxyl,carbonyl groups etc.,which made the internal structure of grease change,thus,the structure of thickening agent was destroyed and the stability was reduced. Anti UV aging agents could reduce the effect of aging on thermal stability.