Electrical ac and dc behavior of epoxy nanocomposites containing graphene oxide

Abstract

This article deals with the investigation of electrical properties of epoxy-based nanocomposites containing graphene oxide nanofillers dispersed in the polymer matrix through two-phase extraction. Broadband dielectric spectroscopy and dc electrical conductivity as a function of electric field have been evaluated in specimens containing up to 0.5 wt % of nanofiller. Nanocomposites containing pristine graphene oxide do not show significant changes of electrical properties. On the contrary, the same materials after a proper thermal treatment at 135 C, able to provoke the in situ reduction of graphene oxide, exhibit higher permittivity and electrical conductivity, without showing large decrease of breakdown voltage. Moreover, a nonlinear behavior of the electrical conductivity is observed in the range of electric fields investigated, i.e. 2-30 kV mm 21 . A new relaxation phenomenon with a very low temperature dependence is also evidenced at high frequency in reduced graphene oxide composites, likely associated to induced polarization of electrically conductive nanoparticles.

Recent advances in graphene/polyamide 6 composites: a review

“…8,57 Many studies have been reported about the electrical conductivity improvement of polymer composites with graphene currently, such as PE, 166 PU, 92,93,167 PET 168,169 and epoxy composites. 170,171 Similar benets to the electrical conductivity can be achieved for PA6 with graphene or graphite. Zheng et al 102 prepared GO/PA6 nanocomposites through a one-step in situ polymerization, and found that the introduction of GO signicantly improved the electrical conductivity of PA6 with a sharp transition from electrically insulating to conducting.…”

Effects of Graphene Coatings on hindering Space Charge injection in Epoxy Resin

“…It is known that, during the epoxy curing phase, some unreacted monomers and hardener can give rise to ionic species in the final polymeric compound. These latter may lead the electrical response once they are subjected to an external AC field [11], as it can be noticed from Fig. 6.…”

Graphene-based polymer composites: What about it for the HV electrotechnical arena?

“…[10][11][12][13][14], provide supporting evidence for a potential use of GO as an additive to form polymer nanos tructured microcomposites. Past and present work concerned polymer matrices of the resin type (epoxy) and olefin (PE).…”