Electrophysical Properties of Low-Density Polyethylene and Zeolite Composites

Composites based on a homogeneous mixture of low-density polyethylene (LDPE) with powdered natural zeolite (clinoptilolite and heulandite of Agdag deposits, Azerbaijan) in the form of films 140-200 mu m thick and 20 mm in diameter have been obtained by hot pressing at a temperature of 403-413 K and pressure of 15 MPa, followed by quenching in a mixture of ice and water. The dielectric parameters (the real part of the dielectric constant (epsilon'), the tangent of the dielectric loss angle (tan delta), and the electrical conductivity (sigma)) of the composite samples of 60 vol % LDPE/40 vol % zeolite and 40 vol % LDPE/60 vol % zeolite have been examined at frequencies of 25-10(6) Hz and in a temperature range of 293-403 K. On the basis of the temperature dependence of the electrophysical parameters of composite samples, it has been revealed that tan delta and sigma increase with an increase in the filler content and this is associated with an increase in the concentration of charge carriers and their mobility. The study of the frequency dependences epsilon ' = f(log nu), tan delta = f(log nu), and log sigma = f(log nu) has shown the presence of two linear regions of the frequency dependences of electrical conductivity, which change according to the law sigma (ac)(nu) similar to nu (0.73), and this is more consistent with the hopping mechanism of electrical conductivity of LDPE/zeolite composites.