Filler‐dependent changes in thermal, dielectric, and mechanical properties of epoxy resin nanocomposites

Abstract

We added nanofillers of MgO, Mg(OH)2, SiO2, and TiO2 to epoxy resin by high‐pressure shearing at a content of 1 vol%. The glass transition temperature (Tg), dielectric properties, and mechanical properties were measured for these nanocomposites. As a result, Tg decreases in all the nanocomposites. When the filler is MgO or Mg(OH)2, the increase of the real part (ϵr′) and that of the imaginary part (ϵr″) of complex permittivity are significantly suppressed at high temperatures by the filler loading. On the other hand, when the filler is SiO2 and TiO2, the suppression of the increase in ϵr′ and ϵr″ is not obvious. Furthermore, regardless of the filler material, the addition of nanofiller hardly affects the mechanical storage modulus at 200°C. These results indicate that the difference in filler material gives more significant effects on dielectric properties than on mechanical properties. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.