Relationship between the carbonyl index (CI) and fragmentation of polyolefin plastics during agingRelationship between the carbonyl index (CI) and fragmentation of polyolefin plastics during aging Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2025-08-012023enThe durability of plastics in the marine environment has emerged as a crucial environmental issue. However, the contribution of several factors and the threshold point after which a plastic product generates secondary micro- and nanoplastics is still unclear. To investigate the interaction of environmental parameters with the physicochemical properties of polyethylene (PE) and polypropylene (PP) films in the marine environment, polyolefin films were subjected to weathering in emulated coastal and marine environments for 12 months, focusing on the relationship between radiation load, alteration on the surface, and subsequent generation of microplastics (MPs). The weight average molecular weight (Mw) was found to be strongly correlated with the generated particles and the Feret diameter, implying the generation of secondary microplastics at decreased Mw. A significant and strong relationship between the carbonyl index (CI) and the Feret diameter for PP films weathered on beach sand was identified. This CI–fragmentation relationship involves three sequential stages and suggests that spontaneous fragmentation occurs at CI values above 0.7.http://creativecommons.org/licenses/by/4.0/Environmental Science & Technology57218130–8138 Syranidou Evdokia Συρανιδου Ευδοκια Karkanorachaki Aikaterini Καρκανοραχακη Αικατερινη Barouta Despoina Μπαρουτα Δεσποινα Papadaki Elisavet Παπαδακη Ελισαβετ Moschovas Dimitrios Avgeropoulos Apostolos Kalogerakis Nikos Καλογερακης Νικος American Chemical Society Polyethylene (PE) Polypropylene (PP) Microplastic generation Carbonyl index Secondary MPs