Vegetable Oils as Base Oil for Industrial Lubricants: Evaluation Oxidative and Low Temperature Properties Using TGA, DTA and DSC

In this paper oxidative degradation of saturated and unsaturated vegetable oils is studied by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) and their low temperature properties are studied by differential scanning calorimetry (DSC). Both non-isothermal and isothermal thermo gravimetric analysis procedures are used for the study. The onset temperatures of oxidative degradation and weight gain in isothermal TGA are taken as measures of oxidative and thermal stabilities. Three vegetable oils namely coconut oil, sesame oil and sunflower oil with varying degree of un-saturation are selected for the study. The results are found to agree with reported results obtained by conventional methods. Several standard methods are currently available for determining the oxidative and low temperature properties of base oils. These methods are extremely time-consuming and data reproducibility between laboratories is poor. TGA, DTA and DSC are excellent tools to evaluate base oils in respect of their oxidative and low temperature behavior in that they produce results quickly, reproducibly and the sample requirement is very low.