Simulated marine weathering of PVC: Surface transformations and microbial interactions

Area of Science:

• Environmental Science
• Polymer Science
• Marine Biology

Background:

• Polyvinyl chloride (PVC) is a durable plastic found in marine environments.
• Understanding PVC weathering in oceans is crucial for predicting its persistence and impact.
• Current knowledge of marine PVC degradation processes is limited.

Purpose of the Study:

• To investigate the degradation of PVC under simulated marine conditions.
• To assess the individual and combined effects of mechanical wave action, light exposure, and microbial activity on PVC.
• To characterize the chemical, physical, and biological transformations of PVC.

Main Methods:

• Simulated marine weathering experiments over 155 days.
• Application of mechanical wave action (W), light exposure (L), and microbial activity (M) individually and in combination.
• Analysis using FT-IR, XPS, contact angle, opacity, microscopy, and qPCR.

Main Results:

• Wave action was the primary driver of PVC oxidation, causing chlorine loss, surface hydrophilization, and reduced clarity.
• Light exposure alone had minimal effect, while microbial activity introduced nitrogen- and carbon-rich functionalities.
• Combined stressors (W+L+M) showed synergistic effects, promoting oxidation, biofilm formation, and biologically mediated transformations.

Conclusions:

• Multifactorial experiments are effective for studying polymer degradation in diverse environments.
• Wave action plays a critical role in initiating PVC degradation in marine settings.
• Accurate prediction of plastic persistence and ecological risks requires long-term studies and molecular-level analysis.