Aqueous reduced graphene/thermoplastic polyurethane nanocomposites

Aqueous reduction of graphene oxide is a low energy and hazardous-chemical free method to produce graphene. In this article, we report the first polymer nanocomposites with aqueous reduced graphene (ARG). Dispersion of ARG in polymer can be challenging because of the aggregation and stacking of single sheets during the removal of water. A novel co-solvent process to blend ARG into thermoplastic polyurethane (TPU) avoids drying ARG by adding an organic solvent before water is completely removed from the aqueous reduction mixture. The dispersion of ARG in TPU was significantly improved using the co-solvent process compared to conventional solvent blending as demonstrated by the mechanical and electrical properties of ARG/TPU composites. Moreover, properties of the co-solvent blended ARG composite are similar to those of the composites of thermally reduced graphene (TRG), which are the best reported to date. We believe that using solvent exchange to avoid aggregation during drying is a general strategy applicable to other nanocomposite preparations.