Chem501 Fall Seminar
Speaker: Dr. Tomonori Saito
Senior R&D Research, Soft Matter Group/Clinical Sciences Division
Oak Ridge National Laboratory
Joint Faculty Associate Professor (Graduate Advisor) The Bredesen Center for Interdisciplinary Research & Graduate Education (The University of Tennessee)
Host: Dr. Brian Long
Title: “Closed-loop Circularity of Plastics by Chemical Upcycling”
ABSTRACT: 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/reconstructing of engineering plastics. One of our approach to enable polymer circularity is to upcycle commodity plastics to vitrimers, new 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 by 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. Furthermore, we have developed highly efficient organocatalysts that enable low-energy and greener depolymerization pathways for condensation polymers. The high efficiency of the organocatalyst enables efficient deconstruction of diverse mixed plastics, addressing one of the major challenges in the field. Our finding opens a new paradigm of mixed plastic deconstruction and can transform plastic recycling toward establishing closed-loop circularity. This presentation will discuss our on-going efforts on chemical upcycling of plastics from multiple DOE funded projects.
BIO: Dr. Tomonori Saito is a senior R&D staff scientist at Oak Ridge National Laboratory (ORNL), and a joint faculty associate professor (graduate advisor) at the University of Tennessee, Knoxville. He is a synthetic polymer chemist (Ph.D. 2008 Virginia Tech), who has extensive experience in the synthesis of well-defined polymers via living/controlled polymerization as well as post-modification of various polymers. He currently leads various polymer science projects at ORNL including polymer upcycling, vitrimer composites, self-healing materials, robotic gas pipeline renewal, polymer electrolytes for fuel cells and flow batteries, and many others. He has published more than 110 peer-reviewed articles, 10 issued patents (two were licensed.), won R&D 100 in 2012, 2016, 2019, 2021.
Thursday, August 25, 2022 at 4:30pm to 5:45pm
Buehler Hall, 555
1420 Circle Drive, Knoxville, TN 37996
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Linda Sherman
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