Investigation On Electrical Ageing And Dielectric Properties Of PE/MMT Nano-composite

Recently, polymer/layered silicate (PLS) nanocomposites have attracted much attention for their perfect performance. Polyethylene (PE) is a kind of plastic used widely in electrical insulation field, so the modification of PE is valuable for science research and engering. However, the majority of polymer nano-composites reported in the literature were polar polymer and the chemical and mechanical properties of the nano-composites, investigation on PE, especially on its dielectric properties were rarely found to be reported.In the present paper PE/MMT nano-composites were successfully prepared by melting intercalation process. We made electrical ageing tests to low density polyethylene (LDPE) and composites which got from melting by LDPE with organic montomorillonite with and without compatibilizer which is maleated polyethylene (PEMA) under a certain voltage. After that, we measured electrical breakdown characteristic and dielectric properties of these materials which are different from ageing time, and got curves of voltage-life, the dependence of the insulation resistivity and dielectric loss factor and permittivity on temperature.The electrical ageing properties of nano-compsites with compatibilizer are better than pure LDPE as well as a typical relaxation loss characteristic could be seen from the curves of dielectric loss factor vs temperature and the peak of them are higher than others.The possible reason may be the compatibilizer containing polar group. It formed a chemical bond between polylene and organo- montomorillonite, and increased the breakdown strength of the nano-compsites.The layered nanoscale structure of the MMT plays the role of barrier and/or trap at interface , on one hand the carrier was scattered, and on the other hand the carrier was captured by the trap at interface between polyethylene and organo-montmorillonite during the carrier transition, as a result the partial discharge in the composite is hold back, and the long time insulation strength and the life of the polymer is improved. In addition, the insulation of the nano-composite with compatibilizer is higher than the pure LDPE and the composite without compatibilizer though is lower than them.