Submitted to: Society of Tribologists and Lubrication Engineers
Publication Type: Abstract Only
Publication Acceptance Date: 3/20/2005
Publication Date: 5/15/2005
Citation: Erhan, S.Z., Sharma, B.K., Adhvaryu, A. 2005. Additive-additive interactions in vegetable oil: the search for synergistic antioxidant using pdsc. Society of Tribologists and Lubrication Engineers. p. 189.
Technical Abstract: Lubricants based on mineral oils render unfavorable impact on the environment. Owing to growing environmental concerns, vegetable oils are finding their way as lubricants for industrial and automotive applications. Vegetable oils offer significant advantages in terms of resource renewability and biodegradability, as well as comparable performance properties to petro-based products. The unique challenges posed with formulations using vegetable oils are poor oxidative and low temperature stability associated with their triglyceride structures. This paper presents a systematic approach to study the extent of antioxidant/antiwear additive synergism in soybean oil using pressure differential scanning calorimetry (PDSC) and the Rotary Bomb Oxidation Test (RBOT). Synergism was investigated on a set of four antioxidants and three antiwear additives. The results indicate that an antioxidant like zinc dialkyldithiocarbamate performed better than diphenylamine and hindered phenol. Also all the antioxidants showed excellent synergism with antiwear additive; antimony dithiocarbamates were followed by molybdenum phosphorodithioate, while an ashless antiwear additive having amine-phosphate didn’t show any synergism. Under the conditions employed certain additive combinations were distinctly superior to commercially available formulations.