A Study on Chemical and Lubrication Properties of Unrefined, Refined and Virgin Coconut Oil Samples

Abstract

In the present work four samples each of unrefined coconut oil (URCO), refined coconut oil (RCO) and virgin coconut oil (VCO) samples collected from different places were evaluated in terms of physicochemical and lubrication parameters. The physicochemical properties of URCO, RCO and VCO were analyzed in terms of kinematic viscosity, Fatty acid profile, Iodine number, Saponification number, free fatty acid, Peroxide value and flash point. The lubrication properties of the oil samples were compared with the aid of four ball tester. The study revealed that fatty acid profile of VCO samples was slightly different from that of URCO and RCO samples. The saponification and Iodine value of VCO samples was also slightly lower than that of URCO and RCO samples. The four ball test results showed that the average coefficient of friction under tested condition was slightly less for URCO and VCO samples when compared to RCO samples. This difference in frictional property was due to the presence of free acid in the URCO and VCO which acted as boundary lubricant. The increased wear observed with VCO and URCO samples was linked to the presence of peroxides.