Tailored dielectric properties of polypropylene nanocomposites through laboratory synthesized titania

Nanofillers have drawn utmost attention for their ability to enhance the dielectric properties of polymers in the field of high voltage insulation. Usually, a small fraction of nanofillers are added to polymers, and promising dielectric property changes are resulted. Titania (TiO₂) nanofiller has been widely incorporated in different polymers for dielectric properties improvements. However, the effects of rutile TiO₂ and anatase TiO₂ on the structure and dielectric properties of polypropylene (PP) nanocomposites have yet to be systematically compared especially from the perspective of nanodielectrics. In this study, the effects of rutile TiO₂ and anatase TiO₂ nanofillers on the structure and dielectric properties of PP were investigated. The rutile TiO₂ and anatase TiO₂ nanofillers were laboratory synthesized through a sol–gel method using two calcination temperatures, i.e., 700 °C and 450 °C, respectively. The results revealed that the rutile TiO₂ and anatase TiO₂ had distinct effects on the structure and dielectric properties of PP nanocomposites. Significantly, the dielectric performance of PP nanocomposites containing anatase TiO₂ outperformed that containing equivalent amount of rutile TiO₂. Possible mechanisms governing these changes are discussed.