Abstract

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Seed oil has been proposed as alternative base fluid for drilling mud but its stability to oxidation is still an issue to deal with. This paper reports the influence of stabilizing neem oil through chemical modification on its flow and electric conduction properties. Ester derivatives were produced from laboratory purified neem oil. The purified neem oil (PNO) was epoxidized to convert the double bonds to epoxy rings in order to eliminate the weak pi-bonds that are susceptible to oxidation. The derived products from these controlled reactions were verified using Fourier Transform Infrared (FTIR) spectroscopy. The viscosity of the epoxy neem was found to have increased. Glycerol was then removed from the epoxy oil to produce alkyl ester of epoxy neem oil. This reduced the viscosity of the epoxy oil. The mid frequency dielectric response of the PNO and its derivatives are related to ionic conduction. PNO has an electrical conductivity of 1.26 × 10-9 S·m-1 at 20ºC; this is about 100 times higher than the conductivity of diesel oil used as base oil for drilling fluid. The bulk conductivity is thermally activated (activation energy = 0.31 eV) and influenced by the liquid viscosity. A higher conductivity was observed for the ester derivatives compared to that for PNO and this may be attributed to polarization of suspended nanoimpurities. The obtained results support the proposition that suspension of conducting nano-particles in the neem oil derivatives will pave way for the production of a suitable base liquid that will provide lubrication and electric current path for a sustainable oil-based drilling fluid for offshore drilling

Keywords: Drilling fluid, Neem oil, Epoxidation, Sustainable materials, electrical conductivity