Effect of extracting method of coconut oils on tribological properties as bio-based lubricant

Abstract

The use of mineral and synthetic lubricants will have long-term impact on the environment. Vegetable oil can be an alternative for substitution due to having significant environmental benefits. In addition, vegetable oils also offer renewable resources and have proven to have excellent lubrication performance for automotive and industrial application. Coconut oil is one of vegetable-based oil that would have prospective characteristics to be exploited as bio-lubricant oil. The origin of coconut oil would distinguish its characteristic, hence differentiating its performance as a lubricant. Indonesia is well known as having abundant source of coconut oil which is made with different extraction methods. Extraction method can be envisaged for improving the performance of coconut oil as lubricant oil. Indonesian coconut oils that had been extracted through dry and wet methods would be a primary concern in this study. The prospective of extracting method of coconut oil as lubricant in term of physicochemical and tribological properties will be investigated. hydrogenated coconut oil (HCO), virgin coconut oil (VCO), and refined coconut oil (RCO) are product of coconut oil extracted from wet and dry, respectively. Results indicated that RCO and HCO posed high viscosity index, high ratio unsaturated to saturated fatty acids, and low wear and friction coefficient which are prospective as base fluid in lubricant industries.

Friction and Wear Characteristics of Bio-Lubricants Containing Clove Oil as Antioxidant

“…Pin-on-disk testing was conducted at low speed (500 rpm) and high speed (1400 rpm). The two levels of speed represent regimes of lubrication, which are boundary and mixed lubrication regimes, respectively, based on a theoretical prediction of the Stribeck curve [16]. Two loads used were 50 and 100 N, which were equivalent to 1.2 and 1.5 GPa, respectively, based on Hertzian pressure.…”

“…According to Ilhami et al [18], euginol in clove oil can be used to minimize or prevent lipid oxidation in food. VCO has the lowest unsaturated fatty acid composition among these oils (Table 1) because the manufacturing process of VCO does not use a heating process [16]. The most common molecules that are attacked by oxidation are unsaturated fatty acids [10].…”

“…The effect of the breakdown of oils due to oxidation could influence the chemical and physical properties of lubricants and increase CoF and wear on palm oil. Chemical and physical properties of lubricants play a role in protecting contact surfaces from wear, especially in the boundary lubrication regime [16]. The effect of clove oil in VCO and HCO in terms of CoF was reduced slightly with increasing clove oil concentrations at low speed (500 rpm).…”

“…In this research, coconut oils and palm oil were used as vegetable base oils. The used coconut oil types were without heat processing (VCO) and with heat processing (HCO) [16]. All three oils were obtained from commercial cooking oils available in supermarkets.…”

“…Composition of unsaturated and saturated fatty acids (UFA and SFA) in VCO, HCO, and palm oil[16,17].…”