Study on the effect of interface bonding strength on the dielectric properties of epoxy nanocomposites

The interface is critical for the design of nanocomposites with desirable properties, this research try to prove the influence of interface bonding strength between nanofiller and matrix on the dielectric properties (dielectric spectroscopy and conduction current) of epoxy nanocomposites. In this experiments, nanofiller/ethanol suspensions were prepared by ultrasonic vibration method, the four kinds of epoxy resin nanocomposites with 3wt% concentration were made, respectively. The zeta potential of the suspensions were measured by ESA method. The dielectric spectroscopy and the conduction current characteristics of nanocomposite were tested. The zeta potential of the four kinds of suspensions according to the order from small to large is ZnO, MgO, Al₂O₃ and SiO₂ successively, SiO₂ nanocomposites shown the lowest permittivity, in addition, the conduction current of the SiO₂ composites was also lowest among them except the MgO composites. The results indicate that the higher zeta potential can represent strong interface bonding and make the permittivity and conduction current of the nanocomposites decrease, this is due to the lower polarization strength. In this paper, the addition of SiO₂ nanoparticles can provide advantageous performance of epoxy nanocomposites among the four kinds of nanofillers. The interface bonding strength has a major influence on the dielectric property of composites.