Dielectric Properties of Thermally Aged Polypropylene Nanocomposites
Asrul Izam Azmi, Kwan Yiew Lau, Nisar Ahmad, Zulkurnain Abdul‐Malek, Chee Wei Tan, Kuan Yong Ching, A. S. Vaughan
Abstract
This article reports on an investigation into the effects of thermal aging on the structure and dielectric properties of polypropylene (PP) nanocomposites. Magnesium aluminate (MgAl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ), calcium carbonate (CaCO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ), and surface-modified calcium carbonate (CaCO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> T) nanofillers have been added to PP and the resulting nanocomposites have been subjected to aging at 110 °C and 140 °C. The results show that unfilled PP experiences a 13% reduction in its dc breakdown strength after aging at 110 °C and that its dc breakdown strength reduces by 27% after aging at 140 °C. In contrast, the reduction in the dc breakdown strength of all investigated PP nanocomposites is much less pronounced than that of the unfilled PP after aging. Specifically, the dc breakdown strength of PP/MgAl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> nanocomposites, PP/CaCO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> nanocomposites, and PP/CaCO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> T nanocomposites reduces by 8%, 14%, and 14%, respectively, after aging at 140 °C. Possible mechanisms affecting the dc breakdown strength of the unfilled PP and PP nanocomposites before and after aging are consequently discussed.