Modelling the dielectric permittivity of nanocomposites - the overlap model

In this work, the properties of the interphase between silica nanoparticles and the host epoxy matrix are analyzed using numerical simulation. Four different composite samples, with 1, 5, 10 and 20 wt% of nanosilica are investigated. The real part of the complex dielectric permittivity is chosen as an indicator of the interphase impact on the dielectric properties, especially for high filler content. Using a Finite Element Method (FEM), the measured real permittivity is fitted and the real permittivity of the interphase is thus computed. After modeling the interphase properties, it was found that and additional factor needs to be taken into account for composites with high particle loading. This factor directly depends of the overlap of interphases for neighboring particles.