LIANA BOGATU, RALUCA ELENA DRAGOMIR, PAUL ROSCA EFFICIENCY OF ANTIOXIDANT ADDITIVES MIXED IN VEGETABLE OILS
The vegetable oils are considered a viable alternative in the manufacture of some industrial lubricants types, as replacement of the mineral base oils. The main issue that has to be solved, in the case of the vegetable oils, is the very poor oxidation resistance that limits their application and period of service. Considering that one of the most common methods for improvement of different characteristics of lubricants is the additivation, this is very often used, also for the oxidation resistance improvement. The antioxidant additives are usually designed for mineral base oils. Considering that, the purpose of the present study is to evaluate the behavior of vegetable oils mixed with suitable antioxidant additive. In this respect, two representative vegetable oils were chosen, characterized and evaluated, in comparison with two mineral base oils. There are many types of additive compositions, but the selected antioxidant additive was one which provides very good results in the mixture with mineral base oils, so, a high performance sulfur-containing hindered phenol component in combination with suitable aminic antioxidant, was chosen. The experimental results have shown a significant different behavior of the additive mixed with the two oil categories, vegetable oils and mineral base oils, behavior that can be explained in correlation with their specific chemical structure.