Impact of Ultraviolet Radiation on an Artifi cially Polluted Silicone Rubber during Inclined Plane Tracking Test

This paper presents experimental results obtained on tracking and erosion resistance of Silicone rubber (SIR) with and without pollutants. The IEC-60587 Inclined Plane Tracking and Erosion Test method combined with UV radiations of different intensities was employed to assess two different formulations with same base polymeric material (SIR). The hydrophobicity recovery property of silicone rubber formulations before and after inclined plane tracking test was studied besides the effect of corona. Some of the physical, thermal and electrical properties were compared before and after inclined plane tracking test. It is inferred from the analysis carried out on the experimental results that the intensity of UV radiation plays a major role in deteriorating the surface characteristics of the material. It is also found that the introduction of UV in the test method has helped in distinctly evaluating polymeric materials. The effect of two different pollutants was not the same on formulations considered for the study, which implies that the additives play a dominant role in the overall performance of the material than the base polymer. The study also revealed that a formulation with a better performance under a certain pollutant need not have to behave the same way under a different pollutant. Presently, CIGRE Working Group (WG D1.14) is active in standardization of material aspects besides developing suitable methodology for the testing of polymeric materials for outdoor insulation application; the inferences appear to be an useful input to both CIGRE working group and International Electro technical Committee (IEC TC 15 PT 2).