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Reference: ISH2015_39

ISH Collection

Effect of nitric acid on the hydrophobicity of HTV and LSR polymeric insulators



Polymeric insulators offer a lot of advantages over ceramic such as light-weight construction, ease of installation and maintenance, vandalism resistance, improved contamination performance due to use hydrophobic materials and compact line design. Overhead transmission lines insulators which located near chemical factories are suffering from industrial pollution that characterized by industrial waste gases produced from the chimneys of factories. Nitric oxide is naturally generated during thunder and lightning, where oxygen combines with nitrogen yielding nitric oxide gas (unstable), this gas combines with atmospheric oxygen simultaneously forming nitrogen dioxides which is dissolved in atmospheric water vapour also forming nitric and nitrous acids. Nitrous acid dissociates to nitric oxide and water. The effect of nitric acid on silicone rubber insulators (either on high-temperature vulcanized silicone rubber (HTV) or liquid silicone rubber (LSR) samples) is thoroughly investigated in this paper. Several specimens were individually immersed in nitric acid with different concentrations for a suitable time. Every 6 hours one specimen is taken off from the solution and then it was investigated by measuring the contact and/or receding angles. The specimens were left to be dried and the contact and/or receding angles were measured to study the recovery phenomena of both HTV and LSR insulators. The experimental results showed that the value of each of the contact and receding angle is decreased with the increasing of the acidity of the solution and with the time of immersion. It is clear that a significant decrease in the receding angle is noticed in case of immersing the LSR specimens in nitric acid.

File Size: 347,4 KB

Pages NB: 3

Year: 2015

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