Rostampour Sara, Cook Rachel, Jhang Song-Syun, Li Yuejin, Fan Chunlei, Sung Li-Piin
PREP Associate, Infrastructure Materials Group, Materials and Structural Systems Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Bio Environmental Science Program, Morgan State University, Baltimore, MD 21251, USA.
Polymers (Basel). 2024 Aug 8;16(16):2249. doi: 10.3390/polym16162249.
Polyethylene terephthalate has been widely used in the packaging industry. Degraded PET micro(nano)plastics could pose public health concerns following release into various environments. This study focuses on PET degradation under ultraviolet radiation using the NIST SPHERE facility at the National Institute of Standards and Technology in saturated humidity (i.e., ≥95% relative humidity) and dry conditions (i.e., ≤5% relative humidity) with varying temperatures (30 °C, 40 °C, and 50 °C) for up 20 days. ATR-FTIR was used to characterize the chemical composition change of degraded PET as a function of UV exposure time. The results showed that the cleavage of the ester bond at peak 1713 cm and the formation of the carboxylic acid at peak 1685 cm were significantly influenced by UV radiation. Furthermore, the formation of carboxylic acid was considerably higher at saturated humidity and 50 °C conditions compared with dry conditions. The ester bond cleavage was also more pronounced in saturated humidity conditions. The novelty of this study is to provide insights into the chemical degradation of PET under environmental conditions, including UV radiation, humidity, and temperature. The results can be used to develop strategies to reduce the environmental impact of plastic pollution.
聚对苯二甲酸乙二酯已在包装行业中广泛使用。降解后的聚对苯二甲酸乙二酯微（纳）塑料释放到各种环境中后可能会引发公众健康问题。本研究聚焦于在美国国家标准与技术研究院的NIST SPHERE设施中，在饱和湿度（即相对湿度≥95%）和干燥条件（即相对湿度≤5%）下，于不同温度（30℃、40℃和50℃）下对聚对苯二甲酸乙二酯进行长达20天的紫外线辐射降解。采用衰减全反射傅里叶变换红外光谱（ATR-FTIR）来表征降解后的聚对苯二甲酸乙二酯的化学成分随紫外线照射时间的变化。结果表明，1713 cm处酯键的断裂以及1685 cm处羧酸的形成受到紫外线辐射的显著影响。此外，与干燥条件相比，在饱和湿度和50℃条件下羧酸的形成量要高得多。在饱和湿度条件下酯键的断裂也更为明显。本研究的新颖之处在于深入了解了环境条件（包括紫外线辐射、湿度和温度）下聚对苯二甲酸乙二酯的化学降解情况。研究结果可用于制定减少塑料污染对环境影响的策略。
