Temperature Characteristics Of Dielectric Property Parameters Of Polyethylene/Montmorillonite Nanocomposites

Polymer/Layer Silicate nanocomposites have attracted much attention for their excellent properties. However, the majority of polymer nanocomposites reported in the literature were involved in polar polymer and seldom seen nonpolar polyethylene (PE) as polymer matrix. For its good performances in electrical insulation properties, Polyethylene is one of the most widely used plastics in the electrical insulation field. Therefore, the modification of PE by nano-fillers has important scientific research value and engineering significance.Polyethylene/montmorillonite(PE/MMT) nanocomposites are prepared by melting intercalation process. The structural features of nanocomposites are introduced, and characterization techniques of structural and properties are summarized. The prepared materials are characteristic by X-ray diffraction(XRD) and scanning electron microscope(SEM), and the result illustrate that the exfoliated nanocomposite is obtained.This paper studied the dielectric property parameters of industrial organic montmorillonite prepared at different melting temperatures. The experiment results show that the temperature profiles of insulation resistivity of nano-composites have positive temperature coefficient(PTC) which is obviously different from PE. The montmorillonite layers may occupy the amorphous region of PE, which lead to the free-volume reduce and carriers'transition difficulty. From the dielectric loss spectrums of polyethylene/montmorillonite composites with or without compatilizer, they show that the polarity relaxation polarization characteristic is caused by introduced organically modified montmorillonite dealt by ammonium salt. Thermal ageing test of PE/MMT nanocomposites is studied. The test results illustrate that nano-structure has formed in polyethylene/compatilizer pre-intercalation montmorillonite composite(PE/M-MMT) and polyethylene/organic montmorillonite composite(PE/O-MMT/C) and the effect of thermal ageing on temperature curves of insulation resisrivity is negligible, absorption peaks of dielectric loss spectrums are decreased and peak temperatures are shifted from 70℃before ageing to 90℃after which show that both PE/M-MMT and PE/O-MMT/C have good heat resistance property.