Macromolecular Design of Thermosets and Vitrimers Synthesized by Acceptorless Dehydrogenative Polymerization

With support of the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Dr. Garret Miyake of Colorado State University will investigate the synthesis and materials properties of recyclable cross-linked plastics (thermosets). Thermosets often have better materials properties, such as higher strength and greater heat and chemical resistance, relative to their non-crosslinked counterparts but are typically more difficult to reprocess or recycle. This research will develop new chemistry to create uniform polyester thermosets that can be self-healable, reprocessable, as well as chemically broken down to their original building blocks for recovery and recycling. The broader impacts of this work will train the next generation of scientists in multidisciplinary materials discovery while the knowledge gained through this research has the potential to help design more sustainable plastics with the goal to minimize plastic waste. This research will develop new catalysts based upon earth abundant metals for acceptorless dehydrogenative polymerization (ADP) to polymerize alcohol functionalized oligomers to ester cross-linked polymer networks. Coupling identical functional groups is hypothesized to be more efficient than coupling complimentary functional groups and thus ADP will produce uniform networks with improved materials properties and the associated vitrimer properties will be more responsive. This work will enhance our fundamental understanding of ADP and the structure-property relationships of macromolecular networks produced using this technique. In addition, this research will advance the circularity of these networks, as they can be depolymerized back to the starting alcohol functionalized oligomers using hydrogenative depolymerization. The design principles developed in this research will guide strategies to realize dynamic cross-linked materials that have the potential to help address plastic sustainability. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.