Dielectric spectroscopy of epoxy-based nanodielectrics with metal oxide fillers

In recent years, nanometal/epoxy resin composites have become the focus of much research because of their wide applications in the electrical industry. Nanocomposites prepared with nano-sized alumina fillers have been shown to have improved dielectric properties e.g. resistance to surface degradation. In our earlier work, we have studied the effect on conduction processes using PDC (polarization-depolarization currents). In this work, we study the dielectric permittivity of epoxy-based nanocomposites. We use dielectric spectroscopy to study the effect of nano-fillers. The filler materials used in the composite are nanometer-sized spherical alumina (Al₂O₃), titania (TiO₂) and zinc oxide (ZnO) particles. In an attempt to identify the conduction processes involved in the various samples, the real and imaginary permittivities are studied at different temperatures, frequencies and humidity. Such a study is expected to signify not only the dominant mechanisms, but also gross differences between the different composites. It has been conclusively shown that addition of nanometric fillers considerably changes water absorption and ultimately conduction processes. The nanocomposites absorb more water as compared to unfilled epoxy. High complex permittivity is observed in nanocomposites at high humidity.