Effects of natural antioxidants on the essential properties of modified Terminalia catappa L. kernel oil: a possible substitute for mineral oil transformer fluid

Abstract

ABSTRACTThis work focuses on the modification of solvent-extracted Terminalia catappa L. kernel oil (TCKO) using the methods of direct purification and transesterification. Selected physicochemical properties of TCKO and modified Terminalia catappa L. kernel oil (MTCKO) samples were evaluated using International Electrochemical commission (IEC) and American Society for Testing and Material (ASTM) standard methods. Furthermore, the effects of natural antioxidants (citric acid [CA] and ascorbic acid [AA]) on these properties (dielectric strength [DS], viscosity, flash point and pour point) of MTCKO were investigated. The introduction of blended and unblended antioxidant samples into the MTCKO increased the DS and flash point while it decreased the viscosity, with no effect on the pour point. The DS of MTCKO samples modified by direct purification and transesterification methods was 32.88 and 33.95 kV, respectively, prior to the introduction of antioxidants. The DS of MTCKO modified by direct purification and transesterification methods after the introduction of AA and AA/CA was 39.46, 46.36, 41.08, and 48.55 kV, respectively. Furthermore, Fourier transform infrared (FTIR) was used to determine the functional groups in the MTCKO, while statistical analysis indicated that both time and particle sizes were significant during oil extraction.