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 (MgAl
₂
O
₄
), calcium carbonate (CaCO
₃
) and surface-modified calcium carbonate (CaCO
₃
T) 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 MgAl
₂
O
₄
possess lowered breakdown strength compared to unfilled PP. In contrast, adding CaCO
₃
to PP results in a higher breakdown strength of the nanocomposites compared to nanocomposites containing MgAl
₂
O
₄
. Meanwhile, nanocomposites containing CaCO
₃
T 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.