(191d) Upcycling Commodity Plastics, Closed-Loop Additive Manufacturing, and Deconstruction/Upcycling of Engineering Plastics

Over 400 million tons of solid plastics are globally produced annually and only ~9% of those are currently recycled in U.S.. To establish closed-loop circularity of plastics, our team has focused on upcycling commodity plastics, establishing low-carbon circular manufacturing, and deconstructing/upcycling of engineering plastics. One of our approach to enable polymer circularity is to upcycle commodity plastics to vitrimers, recyclable and reprocessable crosslinked polymers by the presence of dynamic exchangeable groups. In our study, we upcycled commodity thermoplastic elastomers to exceptionally tough adhesives, that widely exceed the adhesion of commercial adhesives. The incorporated dynamic boronic ester enabled reversible adhesion on many different surfaces, that allows debonding and rebonding with recyclability, a stark contrast to conventional single-use unrecyclable structural adhesives. In another system, we have established closed-loop additive manufacturing of upcycled commodity plastics through upcycling acrylonitrile butadiene styrene (ABS) into a recyclable, robust adaptive ABS-vitrimer (re)printable via the most common additive manufacturing method, Fused Filament Fabrication (FFF). The full FFF-processing of ABS-vitrimer overcomes the major challenge of (re)printing crosslinked materials and produces stronger, tougher, solvent-resistant 3D objects directly reprintable and separatable from unsorted plastic waste. We also focused on developing robust vitrimer resins for carbon fiber composite application, that enables facile reprocessability, repairability, and multi-cycle recyclability. Furthermore, we have developed highly efficient organocatalysts that enable low-energy and green depolymerization pathways for engineering plastics including efficient deconstruction of diverse mixed plastics. Our finding contributes to establish the design principles for energy-efficient polymer deconstruction and lay a versatile platform for polymer upcycling using deconstructed building blocks with closed-loop circularity. This presentation will discuss our on-going efforts on multiple DOE funded projects including BES, EERE VTO, LDRD and others.