The mechanism of UV accelerated aging of polyvinyl chloride in marine environment: The role of free radicals

This study systematically investigated the photo-aging of polyvinyl chloride (PVC) in deionized water, estuary water, and seawater. As the concentration of Cl increases, the carbonyl index (CI) of PVC during photo aging also increases, indicating that Cl plays a dominant role in PVC photoaging in the environment, which enhance carbonyl index and center dot OH radical accumulation. Unlike previous studies, this study discovered that halogen radicals were also generated during PVC aging. Compared to center dot OH radicals, halogen radicals exhibit stronger selectivity and are more conducive to the photo aging of PVC. Additionally, it was found that PVC shows specific toxicity to Paramecia caudatum at various concentrations both before and after aging, affecting the reproduction process of Paramecia caudatum. This study elucidates the mechanism by which anions in natural water bodies affect the rate of PVC aging, providing a scientific basis for understanding the photodegradation of MPs in the ocean.