The degradation of polylactic acid face mask components in different environments
Linxiang Lyu, Monisha Bagchi, Kelvin Tsun Wai Ng, Nektaria Markoglou, Rumpa Chowdhury, Chunjiang An, Zhikun Chen, Xiaohan Yang
Abstract
The disposal of fossil fuel-based plastics poses a huge environmental challenge, leading to increased interest in biodegradable alternatives such as polylactic acid (PLA). This study focuses on the environmental impact and degradation of PLA face mask components under various conditions (UV (Ultraviolet) radiation, DI water, landfill leachate of various ages, seawater, and enzyme). Under UV exposure, notable changes in physicochemical properties were observed in the PLA masks, including increased oxidation over time. Degradation rates varied across environments, with old landfill leachate and enzyme degradation having a notable impact, especially on meltblown layers. Furthermore, it was found that seawater conditions hampered the degradation of PLA masks, likely due to the inhibitory effect of high salt concentrations. The pathways of chemical group changes during degradation were elucidated using 2D-COS (Two-Dimensional Correlation Spectroscopy) maps. The investigation into the release of microparticles and oligomers further revealed the degradation mechanism. Moreover, PLA masks were found to release fewer microparticles when degraded in studied environments when compared to traditional polypropylene masks. Furthermore, correlation analysis highlighted the influence of factors such as carbonyl index and contact angle on degradation rates, underscoring the complex interplay between environmental conditions and PLA degradation. This comprehensive investigation advances the understanding of PLA degradation pathways, which are crucial for mitigating plastic pollution and promoting the development of sustainable products. • UV exposure caused notable changes and increased oxidation of PLA mask components. • PLA mask components exhibited different degradation rates across varying environmental contexts. • The mechanisms during aging and degradation were analyzed based on 2D-COS maps. • Fewer microparticles were released by PLA mask components compared to polypropylene masks. • Seawater conditions impeded the degradation of PLA masks due to the high salt concentration.