Simultaneous Reduction and Polymerization of Graphene Oxide/Styrene Mixtures to Create Polymer Nanocomposites with Tunable Dielectric Constants

Polymer nanocomposites containing carbon nanomaterials such as carbon black, carbon nanotubes, and graphene exhibit exceptional mechanical, thermal, electrical, and gas-barrier properties. Although the materials property benefits are well established, controlling the dispersion of carbon nanomaterials in polymer matrixes during processing is still a difficult task using current methods. Here, we report a simple, yet versatile method to simultaneously achieve the reduction of graphene oxide (GO) and polymerization of styrene to create reduced graphene oxide/poly(styrene) (RGO/PS) nanocomposite materials via microwave heating. The RGO/PS mixture is then processed into films of desired thicknesses by first removing unreacted styrene and then pressing the powder at elevated temperatures. X-ray photoelectron spectroscopy proved that microwave processing was able to reduce GO, which resulted in a change in the carbon-to-oxygen ratio from 2.0 for GO to 4.5 for RGO. Furthermore, the addition of GO to the RGO/PS nanocomposites leads to an increase in the static dielectric constant (ϵ_s) relative to that of pure PS, with a minimal change in tan δ(∼0.06% at room temperature). The simultaneous microwave reduction/polymerization method described here will potentially lead to the production of polymer-based dielectric nanocomposite materials with tunable dielectric constants for energy-storage applications.