[Research Progress on Plastic Aging Processes and Their Environmental Hazards]

Plastic pollution has become a global environmental issue, posing notable threats to ecosystems and human health. Plastic aging is a continuous dynamic process, during which plastics of various sizes are produced and exist, such as large plastics, microplastics, and nanoplastics. Regardless of the size, plastics continuously fragment and release plastic additives and other soluble products. Moreover, due to the same molecular composition, the aging mechanisms and characteristics of micro and nanoplastics are similar to those of macroplastics. However, the smaller the particle size, the greater the potential harm. To enhance understanding of the environmental effects of plastics, this review focused on the entire dynamic process from the initial form of plastics to their degradation and summarized the aging mechanisms involved, changes in properties, and the products released during this process. These products include macroplastics, micro and nanoplastics, plastic additives, and other soluble substances. The paper also summarized relevant studies and main conclusions on plastic aging experiments, further exploring factors that influence the leaching of plastic additives and the release of micro and nanoplastic particles. Finally, it provided a summary of the environmental hazards that were caused by plastic aging products.