Effects of graphene oxide on the formation, structure and properties of bionanocomposite films made from wheat gluten with chitosan

Graphene oxide (GO) was combined with wheat gluten (WG) and chitosan (CS) to prepare bionanocomposite films using a casting method. The films were characterized using a variety of techniques, including scanning and transmission electron microscopies, atomic force microscopy, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, mechanical testing, water swelling, oxygen permeability and contact angle measurements, to determine the effects of GO on the formation, structure and properties of the bionanocomposites. Their formation and properties were found to be dependent on the mixing order of the three components. The added GO was found to strengthen the films, as well as to decrease water absorption and oxygen permeability. These effects were attributed to the good dispersion of GO in the WG/CS matrix enabled by hydrogen bonds. The decreased water absorption could be explained by the increased hydrophobicity. The notable improvement of the properties of the WG/CS films as a result of GO addition makes the films suitable as packaging materials. (c) 2016 Society of Chemical Industry