Flexible Polymeric Films from Starch Reinforced with Graphene Oxide with Microbiological Barrier Properties

In order to meet the current environmental demand for sustainable technologies that promote social well-being, the present work consisted of the development of a starch/graphene oxide nanocomposite, suitable for industrial production of disposable packaging fillers. The gelatinized starch films were prepared ultrasonically and after evaporation of the solvent, the specimens were prepared for the following characterizations: chemical, thermal, structural and morphological using Fourier-transform infrared region, X-ray excited photoelectron spectroscopy, thermogravimetry and scanning electron microscopy, respectively. The mechanical properties were evaluated by tensile testing and dynamic-mechanical analysis, while the moisture barrier properties were evaluated by water contact angle and moisture absorption tests using the gravimetric method. The microbiological barrier properties were tested using the Brain Heart Infusion culture medium. The thermogravimetric results indicated higher thermal stability with the incorporation of graphene oxide. Permeability and microbiological barrier studies indicated that, within twenty days of exposure to biological agents in the laboratory environment, the films presented the desired microbiological barrier properties, preventing contamination of the Brain Heart Infusion culture medium. Analyses of nanoscale morphology by scanning electron microscopy showed a significant increase in the roughness of the cross-section fracture surface with increasing graphene oxide content. So, according to the results obtained in relation to mechanical tests, thermal analyses, moisture barrier and microbiological barrier studies, it was observed that graphene oxide, when added to the starch matrix at levels above 0.7 pph, qualifies this material for applications as a moisture blocking layer for multilayer packaging.