An experimental study about electrical treeing inside LDPE nanocomposites

Electrical treeing in pure LDPE and in three LDPE nanocomposites, filled with fibrous and laminar philosilicates, has been studied. The nanocomposites have been prepared by dispersing into the matrix 10% wt of nano fillers having different aspect ratio: sepiolite, montmorillonite and also sepiolite and montmorillonite together. Both considered nanofillers have been organically modified in order to obtain a homogeneous dispersion and to increase the chemical compatibility with the organic LDPE matrix so to enhance the interfacial interactions. Electrical tests have been performed applying sinusoidal voltage having a 50Hz frequency to a needle-plane electrode configuration in order to induce the formation of electrical treeing inside ad hoc specimens. The outcome evidences that the nanocomposites have a radically different performance in presence of electrical treeing.