Dielectric Properties of Polyethylene/TiO2 Composites

Resumo

The frequency dependences in the range of 25–10⁶ Hz of dielectric properties (real and imaginary parts of complex dielectric permittivity and electric modulus) of composite materials based on high-density polyethylene and dispersed filler TiO₂ are studied. It is shown that the real part of the complex dielectric permittivity ε of composites increases with decreasing frequency. The magnitude of the effect increases with an increase in the TiO₂ content in the composite of more than 20%. At high frequencies >2 × 10³ Hz, the value of ε of composites is practically independent of frequency. The frequency dependences of the electric modulus M—the inverse complex dielectric permittivity—are determined. In composites with a TiO₂ content of up to 20%, the imaginary part of the electric modulus M' decreases with increasing frequency, and in composites containing from 20 to 50% TiO₂, the opposite effect of decreasing M at low frequencies is observed. On the frequency dependences of all dielectric characteristics, there are no peaks indicative of possible mechanisms of dielectric relaxation associated with molecular mobility.