Dielectric properties and morphologies of composites filled with whisker and nanosized zinc oxide

Two kinds of zinc oxide (ZnO) powders, which are ZnO whisker (w-ZnO) and nanosized ZnO (n-ZnO), were used to prepare the composites with a matrix of low-density polyethylene (LDPE). Dielectric constants and losses of the composites were measured in a frequency range of 1–10 MHz. The dielectric constants and losses increase with increasing w-ZnO content in composites. Modified w-ZnO has a remarkable effect on dielectric properties of the composites. Dielectric constants and losses of the composites containing n-ZnO are larger than those containing w-ZnO under the same content. The results can be explained by nanoscale effects. Some theories of mixing laws are also referred to the dielectric properties of composites in this paper.