Upcycle Commodity Plastic Waste to Fully-Recyclable and Self-Healable Polymers

Over 300 million metric tons of plastics are created globally every year but more than 79% of the plastic waste goes to landfills, but only a small fraction (~9%) is recycled and most of the recycled plastic is down-cycled to low-value products such as garden furniture or pots. The accumulation of unrecycled plastics has become a huge global challenge. Here we present a general strategy to upcycle commodity plastic waste to a class of fully-recyclable and self-healable polymers. The idea is that we functionalize the commodity plastic powder with photosensitive dynamic chemical groups can enable light-activated self-assembly of plastic powder into a polymer composite. Thanks to the light-controlled reversible association and cleavage reactions, the mechanical properties of the polymers can be on-demand tuned by the external light. Besides, the interfacial crack can be healed by light-activated re-association reaction. Furthermore, the synthesized polymer can be ground into powder and then reprocessed back to a solid polymer with rebuilt mechanical properties. We show our strategy is universal to various commodity plastic wastes, such as PS, PP, PET, and PE.