Dispersibility and stability improvement of graphite nanoplatelets in organic solvent by assistance of dispersant and resin

To get stable graphite nanoplatelet (GNP) dispersion in organic solvent (ethylene glycol butyl ether acetate), high molecular weight dispersant (BYK-163) and vinyl chloride-co-vinyl acetate resin were added before ultrasonication of expanded graphite. The effects of the resin and dispersant on the dispersion of the GNPs as well as the dispersion mechanism were also investigated. It is suggested that the high molecular weight dispersant, bonding on the GNPs by anchoring group, form a close and thin layer to promote the wetting and foliation of GNPs, whereas a loosely adsorbed resin forms a thick solvent-swollen polymer layer to provide effective steric hindrance for the stabilization of foliated GNPs. The as-prepared GNP dispersion with concentration of 0.5 mg/mL is very stable and shows no deposition after being laid for several months.