Electrical properties of nanostructured polypropylene: a matter of morphology?

This work investigates an alternative view on the mechanisms behind the modification of electrical properties in a filled dielectric, based on the variation of morphological properties of materials. The case of a nanostructured polypropylene-based blend will be analysed, highlighting the morphological changes observed in the bulk of the material with modifications of electrical properties such as space charge accumulation, dielectric strength and conductivity. Results show that nanofillers help inducing an enhanced morphology of the bulk material, with a reduction of phase separation. This in turn results in better breakdown voltage and lower conductivity, but also an increase in space charge accumulation characteristics to unacceptable levels. On the other hand, functionalization of nanoparticles has been proven to be able to reduce charge accumulation to levels lower than the neat base material, despite a similar polymeric morphology. This must be due to the improved filler dispersion observed, clearly showing the added value carried by nanostructuring