(517c) Oxidative Stability and Biodegradability of Bio-Based Lubricants Using the Petrooxy and Bio-Kinetic Methods

The key properties for bio-based lubricants are their biodegradability, cold flow behavior and oxidative stability. In order to be considered as a candidate to obtain bio-based lubricants, a material from renewable sources must provide properties which overcome the disadvantages usually observed for vegetable oils in this application, poor oxidative stability and high pour point. In this study, the oxidative stability and biodegradability of bio-based lubricants were compared to petroleum-based lubricants and vegetable oils through the PetroOXY and Bio-kinetic methods, respectively. Chemical modifications of castor oil fatty acids were carried out using 2-ethylhexanol. The acetylation reactions were performed with acetic anhydride (1:2) using KOH (5 % wt.). Furthermore, commercial antioxidants and phenolic compounds (saturated and unsaturated cardanol), obtained from cashew nut shell liquid, were added to the synthesized samples. The results show that the chemically modified bio-based products exhibited improved oxidative stability (up to 6 times) and depressed pour point (-42 °C) when compared to fresh castor oil. Overall, the addition of antioxidants increased 6 to 20 times the oxidative stability of the bio-based products. The biodegradability tests showed that synthesized samples have half-life around 30 days.