Effects of mica fillers on dielectric properties of polyamide nanocomposites

Complex permittivity, dielectric strength, and electrical conductivity of polyamide-6/mica nanocomposites were measured. By analyzing the permittivity spectra, it was found that the distribution of relaxation times becomes smaller with the addition of nanofillers. This indicates restriction of molecular motion and strong ionic bonds at the resin/mica interfaces. The conduction current was found to decrease with the addition of nanofillers. The barrier effect, formation of nanometric spherulites, and carrier trapping are considered to be responsible, in addition to the above-mentioned two effects at the interfaces. The breakdown strength is independent of the nanofiller content.