Valorisation of Marine Polypropylene Waste: Integrity Assessment and Recycling Performance

Marine plastic pollution represents a persistent global environmental challenge, with polypropylene (PP) being a prevalent component among marine litter. Building on CEST 2023, this study advances PP debris classification and recyclability assessment, introducing a systematic approach for assessing the recyclability prospects of marine-degraded PP. This study establishes a refined integrity categorization of PP debris using Ultraviolet (UV) spectroscopy, tensile testing, and morphological assessment. Subsequently, a comprehensive analysis of mechanical performance was performed by blending different categories of PP debris with virgin PP, applying controlled injection moulding processes. Results confirmed that blending ratios significantly impact the mechanical properties of the final products. Specifically, blends incorporating 50 % lightly damaged PP (LDPP50-VPP50) and 30 % moderately damaged PP (MDPP30-VPP70) yielded the most efficient performance, maintaining mechanical properties within acceptable thresholds for practical applications. This methodology highlights the importance of debris integrity assessment as a decision-making tool in recycling strategies, promoting the valorisation of marine plastic waste and contributing to circular economy models.