Development of recycled disposable mask based polypropylene matrix composites: Microwave self-healing via graphene nanoplatelets

The use of disposable masks is multiplied by thirty compared to the time before Covid-19. Considering that a major part of these masks is made of polypropylene (PP), a significant amount of PP waste is produced each year. It is important to collect and re-evaluate them in a controlled manner so as not to pose a risk of contamination and not to threaten the environment. This study aims to develop composite materials by using recycled PP (rPP) obtained from disposable masks. After pre-treatment of the reinforcements, composites were manufactured and experimental characterizations were performed by using test specimens. In the developed composites, the impact resistance, as well as fracture toughness of rPP, was improved by the reinforcement agents such as Olefin Block Copolymer (OBC) and Graphene Nanoplatelets (GnPs). In addition, microwave self-healing efficiency was proportional to GnPs content and 15% strength improvement was observed for microwave-treated specimens. In the end, SEM microscopy was carried out on the fracture surfaces and toughening mechanisms, including pull-out of the OBCs, cavitation, and stress whitening were demonstrated.