Dielectric study with epoxy-based nanostructured microcomposites containing silica

Material samples were prepared consisting of silica particles in an epoxy matrix. The generic compound contained a large amount of micrometric silica (e.g. 60% wt.) and a few % of nanosilica. Investigation of the microstructure of the samples showed that indeed the microcomposites exhibited a nanostructured morphology. Dielectric spectroscopy was used to compare the behavior of materials differing in composition. Posttreatment using heat was necessary to obtain a reproducible dielectric response. Dielectric features linked to the material compositions were annotated. For the case of 65-% total wt. silica, it was found that when the nanophase varies from 0 to 5%, the increase in the dielectric constant could fluctuate by as much as 10% in the low-frequency range.