Analysis of the dielectric relaxation in reduced graphene oxide/epoxy composites materials using the modulus formalism

This work reports an analysis of the dielectric properties of reduced graphene oxide mixed into epoxy resin, diglycidyl ether of bisphenol A, in the frequency range 10 ^2 –10 ^6 Hz and over the temperature range of 300–400 K, using impedance spectroscopy. For this study, a series of samples were prepared with various filler contents. Using the electric modulus formalism, it has been found that these composites exhibit below and above the percolation threshold ϕ _c a critical behavior of the dielectric relaxation phenomenon due to the single α -relaxation, which is associated with the glass–rubbery transition of the epoxy matrix above the glass transition temperature. The Cole–Cole model of dielectric relaxation was used for modeling the relaxation processes from which we extract the relaxation parameters. The obtained relaxation parameters suggest a behavior close to single relaxation time. Graphical Abstract