Photocatalytic upcycling of polysulfones at ambient conditions

Abstract

Chemical upcycling has the potential to turn plastic wastes into valuable chemicals and promote the circularity of plastics. Polysulfones and relevant composites are plastics with notable chemical durability, resistance and survivability. They are known as super engineering plastics, but they pose enormous challenges for reuse and upcycling. Here we develop a strategy for the chemical upcycling of polysulfones through copper-photocatalysed dual desulfonylative chlorination at ambient conditions, affording high-value-added dichlorinated diaryl ethers. The key to this strategy is cascade homolytic ipso-aromatic substitutions with high selectivity using the chlorine radical. Various types of polysulfones were successfully depolymerized and functionalized, including 12 examples of resins and eight examples of end-of-life plastics. Through gram-scale upcycling and mixed-plastic treatment, we further demonstrated the excellent compatibility and practicality of our strategy. Overall, this work establishes a viable approach for upcycling waste plastics into valuable chemicals, thus contributing to more sustainable plastic waste management and to realizing the circular economy. Despite pressure to improve the circularity of polysulfone plastic waste, upcycling polysulfones remains technically challenging. This study presents a photocatalytic method that can upcycle various polysulfones into valuable chemicals at ambient conditions.