Effect of Magnetite Nanoparticles on the Dielectric Properties of Nanocomposites Based on Linear Low-Density Polyethylene

Abstract

The effect magnetite nanoparticles on the dielectric properties of nanocomposites based on linear low-density polyethylene in the 10−2–105 Hz range of frequencies is studied. It is found that the amplitude of the maximum of imaginary part of complex permittivity grows, and the maximum shifts toward higher frequencies upon an increase of the concentration of magnetite nanoparticles. It is established that the temperature dependence of the inverse relaxation time at low temperatures has the Arrhenius form (the activation energy falls from 0.38 to 0.12 eV as the concentration of filler grows). The slope of the dependence in Arrhenius coordinates rises at high temperatures and is virtually independent of the concentration of filler. DSC data show that when the concentration of filler is increased, the degree of crystallinity of nanocomposites falls from 43 to 34%. An interpretation of the results is proposed by assuming the observed temperature dependence is a combination of those for crystalline and amorphous regions, while the activation energy in crystalline regions is higher than in amorphous ones.