LDPE/EVA nanocomposite lifetime studies

In this work thermoplastic polymeric blends have been investigated. Such blends are based on low density polyethylene mixed in 80∶20 (wt. %/wt. %) ratio with ethylene vinyl acetate. The nanocomposites has been obtained by adding montmorillonite and silica as fillers. The aim is to identify a new class of insulating materials for medium voltage equipment that could substitute the conventional ones characterized by high life cycle costs. The materials have been prepared by twin screw compounding following an optimized procedure that leads to good quality of the blends. The uniformity of the blends have been verified by means of chemical-physical analysis. Suitable specimens have been prepared by hot compression molding setting temperature, pressure and process time parameters. In this way a good thickness uniformity of the specimens has been obtained in order to perform electrical tests and to characterize the prepared blends. The electrical behavior has been investigated by means of electrical strength and electrical aging tests to trace lifetime curves.