The Application of Chitosan as a Modifier for Lubricating Greases Based on Vegetable Oil

The paper focuses on the influence of novel chemical additive on the physicochemical and rheological properties of novel lubricating grease compositions. The mentioned physicochemical tests revealed that the additive influenced positively the dropping point and oxidation stability of the tested lubricating greases as well as on the reduction of oil release from the grease. The introduction of chitosan caused also an increase of dynamic viscosity at lower shear rates and significant changes of viscosity in the low temperatures. The introduction of modifier led to the increase of yield point value of the tested lubricating compositions. Spectral analyses of lubricating compositions after tribological tests showed that during mechanical and thermal excesses, some components of the lubricant undergo chemical reactions with the surface of the friction pair, creating compounds effectively protecting the tribosystem from damage.