Short term effects of DC and AC corona on the surface electrical properties of polymer films

The effects of DC and AC corona on loss tangent measurements in four thin foil polymer samples were investigated. The materials investigated were 25- mu m polyimide (PI), 75- mu m low-density polyethylene, 12- mu m polyester, and 25- mu m polytetrafluorethylene. Surface conductivity measurements of PI samples exposed to negative corona were also made, as were measurements of temperature effects on loss peak position for that material. It was concluded that the measured properties are a surface effect, possibly attributable to surface charges.<
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