DC electrical conductivity of LDPE-based nanocomposites
Paper in proceedings, 2015
This work presents studies of the effect of nanofillers on dc electrical conductivity of polymeric materials, potentially applicable in high voltage direct current (HVDC) cable insulation. Samples of low-density polyethylene (LDPE) filled with nanoparticles of aluminium oxide (Al2O3) and magnesium oxide (MgO) up to 3 wt% were prepared, on which charging currents were measured at 40 and 60 °C and electric stress of 32 kV/mm. Experimental results for nanocomposites were compared with those of reference LDPE. It was found that the addition of nanofillers led to a significant decrease in electrical volume conductivity and the decline depended strongly on filler type, its content and surface treatment. Further, the influence of specimen thickness on the conductivity was examined for verifying the operating conduction mechanisms. An indication was found that the space charge limited current (SCLC) mechanism dominated the conduction process in the reference material, while this effect ceased for the nanocomposites.