Effects of Compression and Silica Addition on the Dielectric Properties of Epoxy Composites

Composite dielectrics and insulators are emerging as replacement of neat epoxy because of their superior characteristics. However, methods of composite preparation, type and size of filler and stresses such as temperature and mechanical stresses influence these characteristics. In addition, inorganic oxides-based epoxy composites are expected to have good dielectric characteristics. In this work, effect of compression and silica on the dielectric properties of epoxy composites with reference to neat epoxy is explored. Epoxy microcomposite (15% by weight silica loading) and nanocomposites (2.5% and 5% by silica loadings) are prepared, and their dielectric properties are investigated before and after compression at 15 MPa. Overall epoxy nanocomposites with 5% nanosilica performed best having 0.09 dissipation factor and dielectric constant of 6.23. After compressing the samples at 70 °C and 15 MPa, dramatic increase in the dissipation factor of microcomposites was recorded where the average $$ \kappa $$ increased by a factor of 1.53–8.27 in comparison with 5.40 in the uncompressed form.