RESUMO
Oxidative stability of prototypical groundnut oil (GO) and mustard oil (MO) blended with a significant characteristic addition of antioxidants, α-tocopherol (α-T) and TBHQ (tert-butyl hydroquinone), at different concentrations was analysed. α-T (natural) and TBHQ (synthetic) antioxidants at a different concentrations from 0 to 20 mg/L were blended with GO and MO to prepare 18 samples. Compositional analysis of groundnut oil and mustard oil was carried out using gas chromatography and mass spectra (GCMS). Electrical properties like dielectric constant, tanδ, specific resistance etc. were investigated at frequencies from 1 Hz to 10 MHz for the modified samples. Thermal properties like breakdown voltage, flash and fire points and viscosity of all samples were also premeditated. It was observed that dielectric constant (ε') of GO reduces from 3.58 to 2.82 with the addition of α-T but increases to 3.29 with the addition of TBHQ, whereas in MO, dielectric constant increases from 2.93 to 3.38 with the addition of α-T and rises to 3.27 with the addition of TBHQ at 15 mg/L. The synergistic effect of antioxidants in regulating the insulation nature of the oil is found to be more effective with α-tocopherol compared to TBHQ in GO. Higher breakdown voltage and more stability were observed in oil with the addition of antioxidant (TBHQ) in low concentration. The study would be useful in the selection of eco-friendly coolants in engineering and industry.
