Upcycling Recycled PET Fibers for High-Performance Polypropylene Composites: Innovations in Sustainable Material Design

Abstract

The growing global plastic waste crisis has necessitated the development of sustainable materials as viable alternatives to conventional plastics. In this study, the fabrication of recycled polyethylene terephthalate (rPET)/polypropylene (PP) composites is investigated. rPET fibers are used as reinforcements within a polypropylene matrix to enhance the sustainability and performance of polymeric composites. By upcycling waste rPET fibers through a dual-surface treatment approach combining nitric acid modification and graphene nanoplatelet (GNP) integration, this study presents a novel method to simultaneously improve interfacial bonding and composite functionality. A key innovation is the use of nitric acid treatment to introduce polar functional groups on rPET, enhancing chemical compatibility with PP and GNP, and resulting in significant improvements in mechanical performance. The tensile strength of the treated PP/PET composites increased by approximately 16.7% compared to the untreated counterparts, rising from ~ 30 MPa to ~ 35 MPa. Furthermore, the incorporation of GNP as a multifunctional nanofiller enhances the mechanical robustness and thermal stability of the composites, making them suitable for demanding industrial applications. This research highlights the dual benefits of waste valorization and material innovation, offering an eco-friendly and structurally efficient alternative to conventional composites. The novelty of this work lies in the synergistic integration of chemical fiber modification and nanofiller engineering to address both environmental and performance challenges in recycled polymer composites.