Dielectric measurements of degradation condition of polymer material surface

Abstract

The application of polymer insulator, such as silicone rubber has been demanded to solve the subjects on a long-term reliability and on a diagnosis techniques. Dielectric measurement of the degradation condition of polymer material is one of the most useful techniques to evaluate these changes on the properties. In this study, a pair of inter-digital electrodes is used to detect the change in dielectric properties of silicone rubbers. It can detect the change in hydrophobic condition of polymer surface and also the change in bulk condition of the polymer. The dielectric property of insulating material is evaluated as loss tangent and capacitance by using the application of ac electric field. The inter- digital electrodes is set only on one side of the sample surface, however, it can evaluate the dielectric property by using the leakage of the electric field lines from the edge of inter-digital finger electrodes on the sample surface to the bulk region of the sample. High field tan/spl delta/-capacitance bridge system can successfully measure the condition of both the surface of polymer and also the bulk of the material for every one cycle of ac electric field application.