Preparation of PP/MgO Nanocomposite Films and Study on Its Dielectric Properties

Polymer nanocomposite dielectrics combine the high breakdown strength of the polymer matrix and the high dielectric constant of inorganic nanofillers, and are widely used as insulating materials for thin film capacitors. However, due to the large difference in dielectric properties between the nanofillers and the polymer matrix, the increase in the dielectric constant of the nanocomposite dielectrics with high doping concentrations is at the expense of the decrease in breakdown strength, which will limit the improvement in energy storage performance. Studies have shown that a small amount of nanoparticle doping will introduce independent interface regions in the matrix, significantly reducing the restriction of the applied electric field on the dipole, thereby affecting the dielectric properties of the matrix. In this paper, polypropylene is used as the matrix, and the polypropylene/magnesium oxide nanocomposite dielectrics with different doping concentrations are successfully prepared by the melt blending method. The broadband dielectric spectroscopy is used to analysis the dielectric properties of samples with different doping concentrations. The test results show that as the doping concentrations increases, the relative dielectric constant of the polypropylene/magnesium oxide nanocomposite dielectrics first increases and then decreases. At a lower doping concentration (0.5wt%), there is a peak in the dielectric constant of the composite dielectrics.