Effects of interaction between filler and resin on the glass transition and dielectric properties of epoxy resin nanocomposites

Polymer nanocomposites are known to exhibit superior insulation performance. As a reason for this, interactions at the filler/polymer interfaces are widely believed. To obtain information on this, the glass transition temperature (T_g), complex permittivity (ε*), and conductivity (σ) were measured in various epoxy resin nanocomposites. As a result, all the parameters (T_g, ε*, and σ) decrease when the filler is MgO, whereas T_g decreases and ε* and σ increase when the filler is TiO₂. This fact clearly indicates that the filler exerts significant influences on various properties such as molecular motions in the host epoxy resin, and that these influences differ profoundly depending on the filler material.