Oxidation Effect on Tribological Pproperties of Rapeseed oil and Lard Mixtures Containing Monoglycerides and Fatty Acids

Vegetable oils and animal fats are increasingly popular base material to produce environmentally friendly lubricants. This is a renewable and easily biodegradable in the natural environment material. The main disadvantage of vegetable oils and animal fats as raw materials and its lubricants is pour oxidation stability. There are already a wide range of environmentally friendly lubricants in the market, while the variety of greases offer is not so high. This research aims to explore the properties of prepared compositions of lubricating greases produced from rapeseed oil and lard, modifying them with monoglycerides, stearic and oleic acids. The plastic properties (penetration) and oxidation influence on tribological and corrosive properties of these compositions were studied. It was found that modifying rapeseed oil and lard with monoglycerides, oleic and stearic acids a few lubricating compositions of NLGI grades can be achieved: soft or very soft rapeseed oil based greases and medium or nearly hard consistency lard based compositions. The oxidation studies showed that it decreases the tribological properties of base and monoglycerides modified lubricants. Oxidation has greater negative impact on lard and lard based compositions. Oleic and stearic acids reduces or completely eliminates the negative influence of oxidation. Corrosion studies have shown that both fresh and oxidized lubricant compositions have no significant affect on copper strip corrosion. DOI: http://dx.doi.org/10.5755/j01.erem.61.3.1763