Environmental degradation and formation of secondary microplastics from packaging material: A polypropylene film case study

A model study on isotactic polypropylene (iPP) films as commonly used in packaging was performed for simulating the process of microplastics formation from large-scale objects like littered packaging material,. Accelerated ultraviolet (UV) ageing in a Xenotest device resulted in chemical degradation and oxidation of the polymer, together with fragmentation into sub-mm particles, within less than 48 h. Combining the results with an independent Arrhenius study allowed an estimate of the lifetime until sub-mm particle formation between 9 months and 3.2 years, depending on location and climate. The findings offer a possible explanation for the mass loss at the lower end of the particle size distribution of environmental microplastics and the divergence between input estimates and actually detected amounts of microplastics. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

A model study on isotactic polypropylene (iPP) films commonly used in packaging was conducted to simulate the formation of microplastics from large-scale objects. The study found that accelerated ultraviolet (UV) aging resulted in chemical degradation and oxidation of the polymer, leading to fragmentation into sub-mm particles. Combining the results with an independent Arrhenius study, the lifetime until sub-mm particle formation was estimated to be between 9 months and 3.2 years, depending on location and climate. These findings provide a possible explanation for the mass loss at the lower end of the particle size distribution of environmental microplastics and the discrepancy between input estimates and actually detected amounts of microplastics.