Dielectric Properties of Low-Density Polyethylene/MgO Nanocomposites

Abstract

Polymer nanocomposite has been attracting much attention as a new insulating material, since homogeneous dispersion of only few nm-sized inorganic fillers can improve various properties significantly. In the present article, we report measurement results of permittivity, conduction current, and space charge distribution profiles observed in low-density polyethylene/MgO nanocomposites with various filler contents. The permittivity shows the lowest value at I-phr addition of fillers and then increases monotonically with an increase in the filler content. The volume resistivity measured under a dc electric field becomes highest at 5 phr in the temperature range between 278 and 363 K. There is a possibility that molecular motions, which help electronic or ionic charge carriers escape from traps by hopping, are restricted by the addition of a proper quantity of nano-fillers. In all the samples, homocharge is found to be formed before the anode. INTRODUCTION Polymer nanocomposite (NC) is an innovative polymer, in which only a small quantity of nm inorganic fillers are dispersed. It has been attracting much attention as an engineering plastic since various properties, especially mechanical and thermal properties, are improved [1]. It is desirable if such NCs can be used as electrical insulating materials [1][2][3][4]. In this research, we measured the permittivity, conduction current, and space charge profile of NCs with low-density polyethylene (LDPE) and MgO.

Precise location of the excessive temperature points in polymer insulated cables

“…Figure 9 shows ε r ' as a function of frequency observed for the LDPE and PVC sheets. While ε r ' increases in PVC with an increase in temperature, it decreases in LDPE, which are in agreement with the literature [8][9][10][11].…”

Influence of homocharges and nanoparticles in electrical tree propagation under DC voltage application

“…The quantity of homocharge is higher in nanocomposites, due to the nanoparticles, which enhance the charge injection from the electrodes. This high quantity of homocharge in the nanocomposite could prevent further injection of charge carriers in the matrix [5][6][7]. This paper deals with the significance of the nanoparticles and homocharges in the prevention of electrical tree growth under DC voltage application.…”

Influence of moisture absorption on space charge property of MgO/LDPE nanocomposite

“…Based on the improved properties, it may apply to HVDC cables as insulating material [1][2][3][4][5][6][7][8]. However, MgO has stronger hydrophilicity, it is found that the dielectric properties of MgO/LDPE get worse when MgO/LDPE had been exposed under air environment for a couple of days.…”