增黏剂对锂基润滑脂流变性能的影响

摘要

Lithium greases containing different kinds of tackifiers were prepared,and their cone penetration and similar viscosity were tested.The influence of tackifier types on the rheological properties were studied by rheometers in two differ⁃ent test modes,one of that is controlled⁃stress rheology measurement under oscillatory strain amplitude sweep,the other is controlled⁃strain rheology measurement under steady stress sweep.The experimental results show that the storage modulus of the greases with tackifiers is decreased and the strain is increased,compared with the greases without tackifiers.The addi⁃tion of tackifiers results in the increase of viscous properties and the decrease of elastic properties of the lithium greases,so the lithium greases with tackifiers are more difficult to flow,and are easier to deform under stress and also easier to recover when stress disappears.Several kinds of tackifiers in study have different extent of influence on the lithium greases,the in⁃fluence of polymethacrylate is more obvious than that of the ethylene⁃propylene copolymer with low molecular weight.%制备含有不同种类增黏剂的锂基润滑脂，测试润滑脂的锥入度和相似黏度；采用流变仪通过剪率控制下的稳态流变试验和应变控制下的动态流变试验，研究增黏剂种类对锂基润滑脂流变性的影响。结果发现，加入增黏剂后，锂基脂的弹性模量减小，形变增大，即弹性特征相对减弱，黏性特征相对增强，从而润滑脂更易变形，不易流动，产生的形变更易恢复；在本研究试验条件下，不同增黏剂对基础脂流变性的影响程度不同，聚甲基丙烯酸酯的影响最为显著，小分子量的乙丙共聚物的影响最小。