Contribution of graphene oxide obtained from exhausted batteries in polypropylene compositions: mechanical, thermal and rheological properties

Particulate matter and volatile organic compounds pose severe threats to human health. Therefore, in this study samples of polypropylene/graphene oxide with varying compositions were prepared for to be tested in automotive sector. Graphene oxide was obtained through an electrochemical exfoliation of graphite recovered from exhausted batteries. The preparation of the composites was performed using graphene oxide at ratios of 0.3%, 0.7% and 1.0% (w/w), already diluted in a hyperdispersant agent. The composites were compared to both pure polypropylene and polypropylene/carbon black composites. The samples were characterized based on their melt flow index, thermal stability, crystallinity, flammability, and mechanical and rheological properties. The formulations containing graphene oxide obtained from the recycling of exhausted batteries exhibited superior thermal properties and melt flow index compared to pure polypropylene. In addition, the composites containing 0.7% of graphene oxide showed an increase in flow index compared to the composite containing carbon black. The rheological properties of samples containing graphene oxide had values closer to pure polypropylene compared to those containing only hyperdispersant or carbon black. The increase in the flow index of a composite containing graphene oxide can result in energy cost savings during processing. Polypropylene/graphene oxide composites present an interesting alternative by replacing carbon black with recycled graphene oxide, both in terms of costs and environmental impact, aligning with the principles of green chemistry.