Relationship between the Carbonyl Index (CI) and Fragmentation of Polyolefin Plastics during Aging.

The 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.

Towards a high quality recycling of plastics from waste electrical and electronic equipment through separation of contaminated fractions.

The aim of this study is to provide an evaluation of the recyclability of plastics derived from electrical equipment from contamination standpoint. A database was created to find trends in potentially toxic elements (PTEs) and bromine concentrations; in relation to unit's application, color, polymer type, and production date. For this study, 142 kg of plastics derived from waste electrical and electronic equipment, from the collection group 5, were analyzed. Less than 1.5 % of the analyzed material indicated hazardous characteristics due to their PTEs concentrations (following RoHS and REACH). Regarding the bromine (Br) content, larger quantities of plastics showed recycling incompatibility; 71 parts with total weight of 11 kg (8 %-wt) contained Br concentrations >2000 mg kg-1. The highest average value of Pb, Cd, Hg and Cr combined falls under the application category 'tools', which was as well the trend in appliances from before 1990. The same trend was observed for Br and antimony (Sb) contents; high concentrations were found in appliances from the 'tools' category. This study concludes that plastics derived from colored appliances and appliances labeled as tools have to be evaluated before being sent for recycling, due to high contamination risks.