Adding nanofillers in polymeric insulating materials: so far so good? The case of polypropylene for DC cables

This paper has the purpose to point at the weaknesses implicit in nanostructuration of insulating polymers for cable insulation, with reference to polypropylene and nanosilica. It also tries to single out which types of properties would be more or less affected by nanofiller introduction, and if in a positive or negative way, depending on nanofiller functionalization process. It is shown, for example, that nanofiller might increase, rather than decrease, space charge and conduction current, as an effect of functionalization, and that a decrease of space charge is not necessarily correlated to an increase of life.