The interest of combining two additives with palm olein as selected lubricant components
Authors: Husnawan M. , Masjuki H.H. , Mahlia T.M.I. 
Published: May 2011

PurposeThe purpose of this paper is to study the effect of palm olein, amine phosphate and 4‐nonyl phenoxy acetic acid (NPAA) added to a commercial lubricant in terms of tribological properties such as wear and coefficient of friction.Design/methodology/approachA tribological study on the lubrication performance of a lubricant‐based palm oil (PO) containing anti‐wear and antioxidant combined corrosion inhibitor additive was carried out using a universal sliding wear machine. In this experiment, amine phosphate and NPAA were selected as additive to be mixed with PO (palm olein) in several concentrations and commercial lubricant 20W‐50 for the tests. Various PO blended samples with additional 1 and 3 percent additive were used in this study. The experiments were performed under 252 rpm sliding speed for 2 h where the oil temperature reached 100°C.FindingsThe analysis showed that the average wear coefficient and the mean wear scar diameter (MWSD) which is normalized to the 1.4 KPa water pressure generates lower values for the PO containing additives than 100 percent PO, commercial lubricant and their blended. The coefficients of friction and wear were also lower for the samples with additives compared to other. To consolidate the result, viscosity of used samples is checked and shows the additives improved the viscosity stability. Finally, the overall study concluded that PO‐added additives have the potential to be one of the ingredients in effective lubricant oil.Research limitations/implicationsThe paper is limited to findings based on a Universal Sliding Machine Test under certain conditions. The test has been conducted on the basis of three types of chemical compounds (palm olein, amine phosphate and NPAA) which are designed as a combination of anti‐wear and antioxidant additive. Wear and friction characteristics of the lubricant with and without these additives are analyzed in this paper. However, the film formation and microstructure analysis of the lubricated materials are excluded in this study.Practical implicationsThis paper shows a significant reduction of average wear rate and friction coefficient when palm olein and additive added to the lubricant compared to pure commercial lubricant. In terms of wear scar diameter (WSD), with additional palm olein and additive produces lower WSD which is under the standard limit of diesel lubricity. These results have confirmed that by using palm olein as renewable component together with amine phosphate and NPAA additive would improve lubrication performance as well as improves biodegradability of the lubricant.Originality/valueThis paper emphasises the advantages of synthetic additives that are derived from renewable resources. Since environmental issues are now stringent, many lubricant industries have focused on environmentally friendly lubricant and researches on this particular area become important. The presented tests have been carried out in the above area which is close to those applied in lubricant industry. Thus, the results are reliable and could be very useful both for lubricant designers and the researchers of lubricant and additive formulation.