Study of montmorillonite concentration on dielectric property and dispersion of cross-linked polyethylene/montmorillonite nano-composites

Polymer nanocomposites can get great improvement in dielectric property without apparent change in their own characters. In this paper, nano montmorillonite (MMT)/cross-linked Polyethylene (XLPE) composite samples were prepared by the melt blending method and then the effect of dispersion of MMT particles on the dielectric property were studied. X-ray diffraction (XRD) and scanning electron microscope (SEM) was used to analyze the dispersion of MMT particles in polymer resin. The results showed that MMT particles can be well dispersed and intercalated in XLPE. The results of TSC showed that the deep trap level and charge density increased as content of MMT increase. Dielectric property shows that the permittivity of XLPE/MMT nanocomposites was higher than that of pure XLPE and increase with MMT concentration. Dielectric loss peak occurred in the low-frequency area, indicating the interface polarization in MMT/XLPE composite. The breakdown field strength of composite materials increased with the MMT concentration. This could also be regarded as the interface effect existed between MMT and XLPE.