AbstractThe results of a comparative analysis performed on specimens of nanostructured epoxy resins obtained by different boehmite filler concentrations are reported in this paper. The specimens were prepared by dispersion of boehmite nanoparticles into a cycloaliphatic epoxy resin cross linked under UV. Photopolymerization process was followed by RT‐FTIR and the properties of uv‐cured films investigated. Dielectric properties, in particular space charge accumulation, are measured as a function of nanofiller content. Results indicate that space charge build up and charge mobility are affected largely by filler content. Concentrations of nanofiller of 5–7 wt % show significant decrease of the space charge with respect to the base‐epoxy resin and an increased mobility of negative carriers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009