Upcycling Poly(vinyl chloride) and Polystyrene Plastics Using Photothermal Conversion.

Area of Science:

• Materials Science
• Green Chemistry
• Chemical Engineering

Background:

• Poly(vinyl chloride) (PVC) and polystyrene (PS) are widely used plastics with low recycling rates.
• Developing efficient recycling strategies for these plastics is crucial for environmental sustainability.

Purpose of the Study:

• To develop a novel photothermal conversion strategy for valorizing PVC and PS plastics.
• To produce valuable chemicals from plastic waste, specifically (1-chloroethyl)benzene.

Main Methods:

• Utilizing PVC's in situ generated HCl and dehydrochlorinated PVC (DHPVC) as a photothermal agent for styrene hydrochlorination.
• Employing white light irradiation for efficient conversion.
• Applying nucleophilic substitution for further derivatization into 1-phenylethanol and fendiline.

Main Results:

• Achieved up to 89% yield of (1-chloroethyl)benzene from PVC and styrene in under 1 hour of white light irradiation.
• Demonstrated successful synthesis of 1-phenylethanol and fendiline via nucleophilic substitution.
• Showcased the system's compatibility with post-consumer PVC and various alkenes.
• Reported 84% yield of (1-chloroethyl)benzene from PVC upcycling with recycled styrene under LED light and 42% yield from co-upcycling of PS and PVC under sunlight in 4 minutes.

Conclusions:

• The developed photothermal conversion strategy offers a simple, efficient, and versatile method for upcycling PVC and PS plastics.
• This approach transforms plastic waste into high-value commodity chemicals and pharmaceutical precursors.
• The method is applicable to real-world plastic waste, including post-consumer materials and plasticizers.