Effect of reduction methods and functionalization on the dispersion of graphene in epoxy

Poor dispersion between graphene nanofiller and polymer matrix would limit the development and application of the polymeric composites. In our study, three reduction methods, chemical reduction using hydrazine hydrate (N2H4 center dot H2O), high temperature, and solvothermal methods were used to reduce graphene oxide; then reduced graphene oxide (RGO) were further functionalized by sodium dodecyl benzene sulfonate (SDBS) and cetylpyridinium chloride (CPC). The functionalized RGO (FRGO) was characterized with Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, respectively. Subsequently, the studied RGO was incorporated into epoxy resin to fabricate composites. Hansen solubility parameters (HSPs) theory was used to predict dispersion of studied RGO in epoxy resin. The compatibility of different RGO with epoxy was calculated by HSPs and compared with the real dispersion of RGO and FRGO in epoxy resin, which was explored through light optional microscopy (LOM). The results indicated that the dispersion of studied RGO in epoxy predicted by HSPs theory is in a good agreement with the experimental results.