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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.

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