Breaking down building plastics: Exploring UV-induced degradation pathway and its impact on structural integrity and microplastics formation

The persistent environmental challenge of plastic pollution has intensified the need to understand the transition of plastics into microplastics. This study explores the degradation of building and construction plastics, i.e., Polymethyl Methacrylate (PMMA), Polycarbonate (PC), and Polytetrafluoroethylene (PTFE), under artificial UV exposure to identify their transition into microplastics. The plastics were exposed to a UV light source of 340 nm for a variation of time up to 1000 h. The results reveal that the UV degradation accelerated the breakdown of these plastics, leading to noticeable changes in their physical and chemical properties. The surface analysis revealed significant crack formation and structural damage, indicating advanced stages of degradation. Optical microscopy and SEM imaging demonstrated the progressive fragmentation of plastics into smaller particles, eventually forming microplastics. The chemical analysis using FTIR and Raman spectroscopy, along with mechanical testing (tensile strength, Young’s modulus, and elongation at break), confirmed that the degradation affected the polymer's molecular structure, weakening the material and contributing to its fragmentation. The findings provide insights into the degradation behaviour of construction plastics under UV exposure and establish links between chemical, physical, and mechanical deterioration and surface fragmentation. This understanding may support future efforts aimed at improving material durability and reducing the potential release of plastic fragments into the environment.