Evaluation of Oxidative and Thermal Stability of Base Oil for Automotive Application

Abstract

AbstractBase oils make up the majority of the content of engine oils and substantially impact the overall performance of the finished lubricant product. The oxidative and thermal stability of the base oil are critical factors in defining the quality of automobile lubricating oil. Thus, it is critical to understand the degrading behavior of base oils and engine oils. The oxidative and thermal stability of several base oils and engine oil were thoroughly investigated in this study. Three distinct types of base oil (base 1, 2 and 3) and motor oil were produced and physically characterized. The samples were dried in a drying oven at atmospheric pressure and 150 ℃ for 24 h. The impact of heat treatment on the samples’ oxidative stability was investigated using a Fourier Transform Infrared Spectrometer (FTIR). The thermogravimetric analysis was used to determine the samples’ thermal stability (TGA). The study was done in an inert atmosphere using nitrogen gas and a 10 ℃ min−1 heating rate from 30 to 900 ℃. The experimental results indicate that base oils and engine oil resisted oxidation since no apparent chemical structural alteration was seen following 24-h heat treatment. Meanwhile, engine oil demonstrated the most outstanding onset temperature of 298 ℃, followed by base oil three (276 ℃), base oil two (275 ℃), and base oil one (262 ℃). Additionally, the TGA profile revealed that engine oil had the highest thermal stability at 5, 50, and 90% weight loss. Base oil three, base oil two, and base oil one all followed this pattern. Nonetheless, further research is necessary to better understand the mechanisms at action and assist in creating an industry-specific optimal solution.KeywordsBase oilsEngine oilOxidative stabilityThermal stabilityInfrared spectra