Determination of the oxidation induction time of mineral insulating oils using a modified EN 14112 method

Zn2Al Layered Double Hydroxides Intercalated with Nitrate and p-Aminobenzoate as Ultraviolet Protective Agents in Low-Density Polyethylene Nanocomposites and Natural Insulating Oils

“…The oxidation induction time (OIT) is the time between the start of the measurement and the onset of a rapid rise in conductivity. 17 The conductivity increases slowly during the early stages of the measurement but increases more rapidly after the OIT is reached. The OIT is easily identified in a plot of conductivity versus time by drawing tangents to the curve or by using the second derivative of the curve.…”

“…Detected OIT until secondary reaction products (polar products of oxidation) is a measure of the time that passes until the oxidation takes place, a property that has a direct relation with conductivity. 17,33 According to the results, the OIT was higher in presence of Zn 2 Al-N-AB ( Figure 8) and the conductivity decreased compared to the pure oil. As observed, when an organic UV absorber was intercalated in Zn 2 Al and mixed with the vegetable insulating oil, the oxidation was lower compared to both oils without additives, indicating Zn 2 Al-N-AB as a possible additive to decrease the oxidation due to air presence, and therefore improving the oxidation stability of the evaluated natural insulating oils.…”

“…The OIT is easily identified in a plot of conductivity versus time by drawing tangents to the curve or by using the second derivative of the curve. 17 The effect of adding Zn 2 Al -N-AB was evaluated by measuring the increase in the conductivity of the distilled water contained in the vial. The powder sample was mixed with 3.00 ± 0.01 g of natural insulating oil (7 wt.%).…”

“…Just as the degradation of polymeric materials is favored by the process of free radical formation in the presence of air, the most common cause of chemical aging of insulating oils is oxidation, so inhibitors need to be used, such as 2,6-di-tert-butylphenol or 2,6 -ditert-butylp-cresol to slow the rate of oxidation. 17 In order to determine the influence of the organic UV absorbent into the LDH nanocomposites on commercial natural insulating oils, evaluating their oxidation catalytic activity when compared with UV unsupported absorbers, we decided also to extend the study by performing preliminary conductivity measurements of natural ester insulating fluid containing Zn 2 Al-N-AB.…”