Effect of high filler loading on polymer/(reduced) graphene oxide nanocomposite coatings†

Synthesis of polymer/(reduced) graphene oxide (GO) nanocomposites based on copolymers of styrene/n-butyl acrylate and benzyl methacrylate/n-butyl acrylate at unusually high filler loadings of up to 45 wt% has been explored using aqueous emulsion-based approaches. Two approaches were investigated: (i) miniemulsion polymerization in the presence of GO, and (ii) physical mixing of aqueous GO with a polymer latex. Nanocomposite films were prepared from aqueous composite latexes at room temperature by drop casting, with conversion of GO to rGO via thermal treatment. The electrical conductivity reaches values of approximately 10² Sm⁻¹ at high rGO contents in both systems, with higher values for physical mixing than miniemulsion at medium rGO loadings. The thermal conductivities increased with increasing rGO content with the highest values of approx. 0.4 W mK⁻¹ – physical mixing systems gave higher thermal conductivities than miniemulsions. Increasing GO loading provided stronger but less flexible materials for both systems.