Effect of the field frequency during treeing tests in silicone polymers with different degree of crosslinking

Electrical treeing in silicone polymers has been investigated using a typical pin-plane geometry. The purpose of this work was to investigate the effect of ac field frequency upon the structure of treeing damage in a range of silicone dielectric materials. The liquid components were cured using different crosslinking ratios and hence both gels and elastomers were formed possessing a range of mechanical stiffness. These materials were characterized mechanically with an AR-G2 Rheometer. The results suggest that there is a clear dependence of the tree fractal dimension upon the applied ac voltage frequency and the sample's microstructure as characterized by oscillating rheometry.