Electrical properties of polyethylene/aluminum nanocomposites

Understanding electrical properties of polymer nanocomposites is of great significance in order to diagnose and analyze physical and chemical behaviors of the composites as well as their own dielectric properties and can provide valuable data for improving the characteristics of the nanocomposites. In this work, the solution compounding method was used to prepare the polyethylene (PE)/aluminum (Al) nanocomposites. The dielectric permittivity and loss tangent of the PE/Al nanocomposites with different nanofiller loadings were investigated in the broad frequency range from 0.1 Hz to 10 MHz and the direct current (dc) conductivity and the dielectric breakdown strength of the PE/Al nanocomposites were also studied. The research results have shown that the dielectric permittivity shows different behaviors in the low and high frequency range. The permittivity values of the nanocomposites with the nanofiller loading levels of 0-48 wt % are found to show no percolative characteristics in the low frequency range below a few kilohertz whereas they tend to increase with the nanofiller loading increasing up to 24 wt % and show the percolative threshold. dc conductivity and dielectric breakdown strength of the nanocomposite are also observed to have percolation threshold characteristics, but the percolation phenomenon is observed to be rather early in the dielectric breakdown strength measurement than that found in the dielectric permittivity and dc conductivity tests because of the difference of the applied voltage level.