Structure-dielectric property relationship in polypropylene/multi-element oxide nanocomposites

This paper reports on an investigation into the effects of different multi-element oxide nanofillers on the structure and dielectric properties of polypropylene (PP)-based nanocomposites. Magnesium aluminate (MgAl2O4), calcium carbonate (CaCO3) and surface-modified calcium carbonate (CaCO3T) have been added to the PP to determine their effects on thermal properties, structural changes, dielectric response and breakdown strength. The results show that PP nanocomposites containing MgAl2O4 possess lowered breakdown strength compared to unfilled PP. In contrast, adding CaCO3 to PP results in a higher breakdown strength of the nanocomposites compared to nanocomposites containing MgAl2O4. Meanwhile, nanocomposites containing CaCO3T possess the highest breakdown strength among the systems considered. Possible mechanisms governing these dielectric property changes under alternating current and direct current electric fields are discussed