Effect of oxidation degrees of graphene oxide on the structure and properties of poly (vinyl alcohol) composite films

In this work, graphene oxide (GO) was synthesized by the traditional Hummers method and the composite film of poly (vinyl alcohol) (PVA)/GO was prepared using solution casting method. Different oxidation degrees of GO were achieved by varying the content of oxidizing agent. The structure and properties of GO and PVA/GO film were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), tensile and oxygen barrier tests in detail. The natural graphite was well exfoliated and oxidized, and higher oxidation degrees and better layer structure of GO were achieved with higher loading of KMnO4 oxidizing agent. For the PVA/GO composite film with the same content of GO, both tensile strength and elongation at break were improved with the increase of oxidation degrees of GO. In addition, a good improvement in the barrier properties of the PVA/GO composite film was also achieved. The oxygen permeability coefficient of composite film was reduced with the increase of oxidation degree compared with the neat PVA film.