Dielectric investigation of high density polyethylene loaded by ZnO nanoparticles synthesized by sol–gel route

Zinc oxide nanoparticles (ZnO NPs), with wurtzite structure, were synthesized using sol–gel route. Both the microstructure and morphology of the synthesized ZnO NPs were examined using X-ray diffraction, Fourier transform infrared and high-resolution transmission electron microscopy. The synthesized ZnO NPs up to 5 wt% were introduced to high density polyethylene (HDPE) using melt blending technique. The dielectric properties of the fabricated HDPE/ZnO nanocomposites were studied by measuring the dc dielectric breakdown strength at constant 1 kV/s ramp. The dielectric strength values were showed ZnO nanofiller concentration dependency. Enhancement in breakdown strength has been observed with addition of ZnO NPs and reached to 17 ± 3.1 % (for HDPE/1 wt% ZnO) with respect to the pure HDPE sample. The real part of the permittivity ( $$\varepsilon^\prime $$ ) and the loss tangent ( $$\tan \delta$$ ) dependency on filler concentration was studied under different applied frequency values from 1 kHz to 1 MHz. As well as the variation of the dielectric parameters ( $$\varepsilon^\prime $$ and $$\tan \delta$$ ) was studied throughout temperature range from room temperature to 120 °C.