A Three-Dimensional Stochastic Model for the Study of Treeing in Epoxy and its Nanocomposites

Incorporation of nanometric fillers into polymers is expected to retard tree growth. In this work, a 3-dimensional (3D) model is developed for the study of electrical tree growth in nanodielectrics. It should be noted that the radii of the tree erosion channels are comparable or larger than the diameter of nanometric fillers. Therefore, a three-dimensional model is imperative to compute the local field intensification accurately. The effect of the size and dielectric constant of the filler particles is studied. With the incorporation of nanofillers, electrical tree progression along the axial direction is hindered. Owing to the high dielectric constant of the fillers, field enhancement is seen to occur in the regions around the nanoparticles, and trees tend to grow around the particles. This results in the formation of bushy trees. This may be correlated with the increase in time to breakdown through treeing reported in nanocomposites. The size of the particles also plays a significant role.