Molecular Weight Control via Cross Metathesis in Photo‐Redox Mediated Ring‐Opening Metathesis Polymerization
Victoria K. Kensy, Rachel L. Tritt, Farihah M. Haque, Laura Murphy, Daniel B. Knorr, Scott M. Grayson, Andrew J. Boydston
Abstract
Photo-redox mediated ring-opening metathesis polymerization (photo-ROMP) is an emerging ROMP technique that uses an organic redox mediator and a vinyl ether initiator, in contrast to metal-based initiators traditionally used in ROMP. The reversibility of the redox-mediated initiation and propagation steps enable spatiotemporal control over the polymerization. Herein, we explore a simple, inexpensive means of controlling molecular weight, using alpha olefins as chain transfer agents. This method enables access to low molecular weight oligomers, and molecular weights between 1 and 30 kDa can be targeted simply by altering the stoichiometry of the reaction. This method of molecular weight control was then used to synthesize a functionalized norbornene copolymer in a range of molecular weights for specific materials applications.