Dielectric properties of polypropylene containing synthetic and natural organoclays

Fully synthetic tetrasilisic mica from Topy Co., Ltd. and Cloisite ® powder of Wyoming natural montmorillonite clay from Southern Clay Products were used to manufacture polypropylene-based nanocomposites with organoclay concentrations up to 8%-wt. Both types of nano-filler increase the AC breakdown strength by approx. 10% over the unfilled material. However, the resistance to partial discharges is significantly improved, with both nano-fillers yielding similar results. Nano-fillers increase dielectric losses of PP over broad frequency and temperature ranges. Specimens containing natural clay show higher losses than the specimens containing synthetic clay, especially at higher frequencies and temperatures.