Electric strength and dieletric properties of µm-polymer-films

The electric strength and the dielectric properties of different polymers with film thicknesses from s = 1 ... 100 μm are presented. The experimental data of the electric strength of PMMA and an acrylic polyester resin is obtained without partial discharges by the use of a special test item design. Based on these results a model is then presented which may describe the breakdown mechanism in consideration of the molecular properties of the polymer. Therefore the formalism of Townsend mechanism, which is known from the breakdown of gases, is used. The results of this model calculation match the experimental data.