Online study of the plasma-accelerated aging process and toxicity of polyethylene terephthalate

Plastic aging occurs in all environmental media and affects their environmental behavior and toxicity. In this study, non-thermal plasma was applied to simulate the aging process of plastics, with polyethylene terephthalate (PET-film) being used as a model. The surface morphology, mass defects, toxicity of aged PET-film and the generation of airborne fine particles were comprehensively characterized. The surface of PET films began to become rough and then gradually became uneven, generating pores, protrusions and cracks. The toxicity of aged PET films was assessed in Caenorhabditis elegans which significantly reduced head thrashing, body bending and brood size. A single particle aerosol mass spectrometry instrument was used to characterize the size distribution and chemical composition of airborne fine particles in real-time. Few particles were observed during the first 90 min, while the generation of particles accelerated significantly after aging time beyond 90 min. For two pieces of PET film with surface area of 5 cm², during the 180 min, at least 15113 ± 153 fine particles were generated, having a unimodal size distribution with a peak of 0.4 µm. The main components of these particles included metals, inorganic non-metals, and organic components. The results provide useful information on plastic aging and are beneficial in assessing the potential environmental risks.