Investigation of shear stability of commercial polymer of viscosity index improver for determination of engine oil optimal formulation

Document Type: Research Paper


1 Department of Chemistry, North Tehran Branch, Islamic Azad University, Tehran, Iran

2 Young Researchers Club of Omidieh Azad University


The lubricating oils in each mechanical device are affected by shear forces. Polymers in lubricating oils engine, in particular, undergo many changes because of the influence of the applied forces. Awareness of these changes can help us to design optimal formulations. In this work, shear stability of four commercial was studied. Calculation of various parameters about viscosity in the enhancing were performed and compared. The results of this study can be used for optimizing the usage of polymers in engine oil.