Electrical treeing in nanocomposite based on LDPE/EVA blends

The aim of this work is the investigation of the performances of nanocomposite materials in the presence of electrical treeing. The nanocomposite materials based on polyolefin matrices were prepared by extrusion and then molded into slabs from which it was possible to prepare apposite specimens to perform electrical treeing tests. The polymeric employed matrices are low density polyethylene (LDPE) and ethylene vinyl acetate (EVA). The considered fillers were commercial modified montmorillonite having a lamellar structure and unmodified silica presenting a spherical shape. The behavior of the different materials were compared and correlated with the material properties and structure. The treeing inception voltage (TIV) and the time to breakdown (TBD) as the final event of the electrical tree growth were considered. Furthermore, in order to identify the presence of defects inside the specimens due to the preparation process the partial discharge (PD) activity was monitored. The PD patterns were acquired by a phase resolved partial discharge analyzer (PRPDA).