Polyethylene terephthalate (PET) is commonly used in water bottle manufacturing because of its low cost, transparency, lightweight nature, and durability. However, PET can degrade when exposed to sunlight and high temperatures for long periods. This study developed a predictive model to evaluate photodegradation behavior of PET water bottles under different sunlight conditions. The investigation focused on thermal degradation kinetics, UV absorbance changes, and chemical migration through diffusion. Results showed that higher UV intensity and temperature accelerated PET degradation, leading to discoloration and increased migration of compounds such as antimony. Under extreme sunlight exposure, antimony levels approached critical safety limits within a short time. Survival analysis further indicated that the lifespan of PET bottles decreased significantly, from several hundred hours under normal conditions to less than two days under severe exposure. Predictive model showed good agreement with previously reported studies and provides useful insight about durability, stability, and safety of PET packaging materials under environmental stress conditions.
Mahmood et al. (2026) studied this question.