(201c) Selective Deconstruction and Upcycling of Condensation Polymers

Condensation polymers such as poly(ethylene terephthalate) (PET), polyamides (PA), polyurethanes (PU), and polycarbonate (PC) comprise ~30% of the global plastic production. The catalytic deconstruction is one of the major paths for chemical recycling of condensation polymers. Although there has been progress on chemical recycling of condensation polymers especially PET, most condensation polymers are not recycled because of the difficulty in depolymerization to pure building blocks especially from mixed state in an energy efficient manner. Here, we have developed a tailored organocatalyst to enable low energy depolymerization pathways for condensation polymers. Our catalyst allows glycolysis of PET, PA, PU, PC and their multiple mixture at moderate temperature with high yield. A wide range of post-consumer plastics waste, such as bottles, packaging, foam, carpet, etc. is readily deconstructed into monomers with high efficiency. The Life Cycle Assessment indicates that the reproduction of various condensation polymers from the deconstructed monomers will result in a significant reduction in greenhouse gas emissions and energy input. Furthermore, we have developed a path to deconstruct those condensation polymers to selective length of oligomers. We have utilized those deconstructed building blocks to synthesize upcycled polymers, and the upcycled polymers can be further deconstructed to reusable building blocks. Such circular design contributes to establishing new closed-loop circularity of polymers by energy efficient selective deconstruction and upcycling of various commodity plastics.