Electrical conduction of metallized BOPP films based on revised Poole–Frenkel effect

Biaxially oriented silica–polypropylene nanocomposites for HVDC film capacitors: morphology-dielectric property relationships, and critical evaluation of the current progress and limitations

“…The hopping distance λ was found to increase from 0.21 nm (unfilled BOPP) to 0.72 nm (4.5 wt% silica): while hopping distance values in the similar range have also been reported previously for e.g. BOPP, PET and PS films, 16,95 the values for λ derived herein are generally very low when relating them to resulting trap density (in the range of 10 27 m −3 or more) 5,15 and certainly too low to be linked with the silica inter-particle distance statistics (see Fig. 3d).…”

“…The hopping distance 𝜆 was found to increase from 0.21 nm (unfilled BOPP) to 0.72 nm (4.5 wt-% silica): while hopping distance values in the similar range have also been reported previously for e.g. BOPP, PET and PS films 16,95 , the values for 𝜆 derived herein are generally very low when relating them to resulting trap density (in the range of 10 27 m -3 or more) 5,15 and certainly too low to be linked with the silica interparticle distance statistics (see Figure 3d). Aside from the evident limitation of the hopping conduction model to fully describe the TSPC process, the most intriguing feature for the TSPC spectra of the silica-BOPP films in Figure 10 is however the saturation (or even decrease) of the thermally stimulated conduction current at the highest temperatures of >120 °C under moderate electric field stresses (<250 V/µm), an effect which becomes more pronounced with increasing silica concentration from 1.0 to 4.5 wt-%.…”

Determination of Volume Conductivity of Thin Polymeric Films Using Corona Triode, When the Current through the Sample Depends Quadratically on Grid Potential

“…It is noted that, the experimental constants (Table 1) are in full accordance with the conditions expressed by Equation (8), Equation (9) and Equation (18).…”

“…The increase of crystallinity results in the reduce of the conductivity in biaxially oriented polypropylene films [18]. Several studies for PP and Trespaphan, report volume conductivity values of 10 S m − − ⋅ order of magnitude is also reported [18], found by the "static" methods with various geometrical configurations. The above reported data are considered to be in good agreement with our results, obtained by the corona triode method.…”

“…The reason for this may be related to the crystallinity degree, that is increased in biaxially oriented polypropylene films (Trespaphan) compared to unoriented films (PP) [17]. The increase of crystallinity results in the reduce of the conductivity in biaxially oriented polypropylene films [18]. Several studies for PP and Trespaphan, report volume conductivity values of 10 S m − − ⋅ order of magnitude is also reported [18], found by the "static" methods with various geometrical configurations.…”