Exploring polystyrene weathering behavior: From surface traits to micro(nano)plastics and additives release

Area of Science:

• Environmental Science
• Polymer Science
• Materials Science

Background:

• Plastic weathering in natural environments is complex, releasing harmful microplastics, nanoplastics, and additives.
• Understanding these releases is vital for assessing plastic environmental risks.

Purpose of the Study:

• To systematically investigate the weathering process of polystyrene (PS) under UV irradiation and mechanical agitation.
• To analyze the release patterns of microplastics, nanoplastics, and additives over time.
• To establish correlations between plastic aging and product release.

Main Methods:

• Polystyrene (PS) samples were subjected to UV irradiation and mechanical agitation for varying durations (1-20 days).
• Physical and chemical changes (aging, yellowing, brittleness, carbonyl groups) were monitored.
• Released microplastics and nanoplastics were analyzed for size distribution using laser infrared and Raman spectroscopy.
• Detected and quantified released additives and soluble products.

Main Results:

• PS aging indicators (yellowing, brittleness, carbonyl groups) increased with weathering duration.
• Surface weathering progressed from oxidation to cracking and flaking.
• Product release positively correlated with plastic aging degree and among released products.
• Microplastic size (10-20 μm) remained dominant, while nanoplastic sizes decreased.
• 20 different chemicals, including additives, were detected after 20 days, with release dependent on aging time, type, and quantity.

Conclusions:

• Plastic weathering accelerates the release of microplastics, nanoplastics, and additives.
• The study clarifies product release patterns and their interrelationships over time.
• Findings aid in predicting and assessing the environmental pollution caused by plastic weathering.