Chemistry Department Seminar: Featuring Prof. Junpeng Wang, University of Akron, "Applying Physical Organic Chemistry Principles to Develop Chemically Recyclable Polymeric Materials"

February 15, -
Speaker(s): Prof. Junpeng Wang, University of Akron
Seminar hosted by Prof. Stephen Craig.

Abstract: Abstract: Synthetic polymers such as plastics, nylon, and synthetic rubber have been used in nearly every aspect of modern life; the dominant use of these polymeric materials is driven by their durability and versatile thermomechanical properties. However, the excellent thermal and chemical stability of commercial polymers makes them challenging to recycle and reuse. Currently, over 300 million tons of plastics are produced each year and 95% of them are not recycled. Consequently, most polymer products are consigned to landfills or thrown into the ocean, causing serious environmental concerns. Moreover, the production of polymers consumes finite fossil resources such as petroleum and coals, and the inability to recycle these materials causes concerns regarding the sustainability of their use. Sustainable polymers have received considerable attention as an option for sustainable materials. Despite the developments, few chemically recyclable polymers can match the stability and mechanical properties of the polymeric materials in current use. This presentation will showcase our recent effort in overcoming these challenges by applying physical organic chemistry tools. Guided by ring strain energy calculations, we developed a new class of depolymerizable polymers from fused-ring cyclooctenes; the fused-ring system lowers the ring strain energies of the monomers and allows the corresponding polymers to depolymerize into the monomers. Importantly, the polymers show excellent thermal stability, and their thermomechanical properties can be tuned-by varying the functional group on the fused ring-to access the properties of both rubber and plastics. In addition, cis-to-trans isomerization of cyclooctene significantly increases the ring strain energy to enable living ring-opening metathesis polymerization at monomer concentrations ≥ 0.025 M. The use of excess triphenylphosphine (PPh3) was found to be essential to suppress secondary metathesis and depolymerization. Using the living polymerization, we demonstrate the preparation of depolymerizable block copolymers and bottlebrush polymers. The high-driving-force living polymerization of the trans-cyclobutane fused trans-cyclooctene system holds promise for developing chemically recyclable polymers of a wide variety of polymer architectures.

To learn more about Prof. Junpeng Wang research, please visit:
https://www.junpengwanglab.org
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Chemistry

Chemistry Department Seminar: Featuring Prof. Junpeng Wang, University of Akron, "Applying Physical Organic Chemistry Principles to Develop Chemically Recyclable Polymeric Materials"

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Angela Mosley