In this paper we determine for the first time the volume conductivity of polyethylene (of 40 μm and 50 μm thickness), using the positive corona triode. A general theory of flowing of the current through the sample, when it depends linearly on the grid potential, is formulated. A concrete methodology for the definition of volume conductivity is composed. The volume conductivity of polyethylene lies within the interval: These results obtained using the corona triode are closely similar to those obtained using the standardized "static" methods, thus showing its superiority to the "dynamic" method of electronic radiation.

In this paper, we determine the surface and volume electrical resistivity of the 50 μm thick cellular polypropylen (VHD50), for the temperature range 393–453 K. For this we use a contemporary methodology, which consist of a voltage measurement across the sample, with a known current flowing through it. This methodology includes a three-electrode system, which allows us to estimate the resistivity of the samples, based on their corresponding total resistances. The electric fields applied for a time interval of 1 min are of the order of 200 kVm−1. The order of magnitude of surface and volume electrical resistivity is 1013 Ω and 1011 Ωm, respectively. For both types of the resistivity, the temperature dependence is an increasing or decreasing exponential function, depending on the type of the activation energy, (its average value for the temperature range mentioned above is 41,20 kJmol−1), totally confirmed by the corresponding theoretical interpretation, conditioned by the ionic conduction.The methodology and equipment used, as well as the satisfying accordance with the results, found out directly or indirectly with the consulted literature, confirm the high accuracy of experimental measurements.

In this paper, the effect of polarity on the volume conductivity of Kapton and polyethylene (PE), determined using the corona triode method, when the sample current depends linearly on grid potential, was studied. For the determination of volume conductivity, in addition to the analytical method, for the first time, a graphical method is presented as well. According to the experimental results, obtained by both methods, the volume conductivity values of negative corona charged samples were higher than those of the samples charged by positive corona. Considering the different nature of positive and negative coronas, these differences in results are to be expected and are in full accordance with the theoretical considerations as well. On the other hand, the good agreement between the analytical method results and those obtained by the graphical method, indicates high accuracy of the proposed analytical formula. Meanwhile, the satisfying accordance of experimental results with those found by the classical "static" and "dynamic" methods, confirms the accuracy of the corona method, for the determination of volume conductivity of polymers.

In this paper is determined the volume conductivity of thin polymeric films using the corona triode method, when the current through the sample exhibits a quadratic dependence on the grid potential. Based on the experimental data, for the first time, an effective methodology for the determination of volume conductivity, graphically and analytically, is composed. The results obtained by the proposed analytical formula, for polypropylene and Trespaphan, with two different configurations of structures, are closely similar to the graphical method results. In addition, the satisfying accordance of our results, with the results, found out with the consulted literature, obtained by the "static" methods, confirms the accuracy of the proposed methodology, for the determination of volume conductivity of thin polymeric films, using the corona triode.

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