CAREER: CAS: Copolymerization of Vinyl Monomers with Isocyanides for Degradable Polymers

Princeton University, Princeton NJ

Investigators

Abstract

With the support of the Macromolecular, Supramolecular, and Nanochemistry program in the Division of Chemistry, Erin Stache of Cornell University is developing degradable polymers from monomers that are building blocks commonly found in commodity plastics. Polymerization processes will be designed to incorporate degradable functionality along the main polymer backbone. This polymer chain is designed to incorporate functionalities that allow for chain cleavage in the presence of light, rendering the commodity polymers photodegradable. The research team will also investigate the mechanistic and kinetic features of the developed polymerizations to understand further and optimize the reaction conditions and expand the monomer types that can be used in these processes. From the sustainability point of view, the design principles associated with this project have the potential to provide a promising and viable solution to the current challenges related to the widespread usage of non-degradable commodity plastics. The education and outreach activities will focus on educating the public across age demographics on the nature of the recycling industry and the science behind polymers and their structure. Additionally, training workshops will be developed to encourage the public to make an impact in their household and community. The efforts to further bring plastics knowledge prowess to general society will be enhanced through social media outreach using various platforms. This project will focus on developing controlled polymerization of isocyanides and vinyl monomers to install degradable functionality into the backbone of commodity polymers. In the first objective, kinetic and mechanistic aspects of cobalt-mediated radical copolymerization of isocyanides and acrylates will be systematically investigated. Strong emphasis will be placed on understanding (a) cross-propagation of activated acrylates with isocyanides to form imidoyl radicals and (b) intermolecular addition of the imidoyl radical to acrylates prior to alpha- or beta-scission that could result in the chain termination and/or transfer. The second objective will study the properties of isocyanide/acrylate copolymers, hydrolysis to afford the corresponding poly(acrylates-co-ketones), backbone elaboration, and degradation behavior of isocyanide and ketone copolymers. Lastly, the ambiphilic nature of isocyanides in a cationic copolymerization of vinyl monomers to access new copolymers will be exploited. Investigation of the mechanistic aspects of copolymerization of isocyanides with vinyl monomers could lead to a development of new and more versatile controlled radical polymerization methods. Additionally, this research has the potential to offer a facile route to a novel class of degradable polymers and to provide important insight into the percentage of imine or ketone functionality incorporation needed to both allow for photodegradation upon appropriate exposure and yet otherwise maintain desirable polymer properties. 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.