Modulating Polyolefin Copolymer Composition via Redox-Active Olefin Polymerization Catalysts

The ability to precisely modulate polymer architecture and composition is a long-standing goal within the field of polymer synthesis. Herein, we demonstrate that redox-active olefin polymerization catalysts may be used to predictably tailor polyolefin comonomer incorporation levels for the copolymerization of ethylene and higher alpha-olefins. This ability is facilitated via the utilization, of a redox-active olefin polymerization catalyst that once reduced via in situ addition of a chemical reductant results in a notable drop in alpha-olefin incorporation. We attribute this behavior to the reduced catalyst's increased electron density and its concomitant decreased rate of alpha-olefin consumption. These results are supported by investigations into propylene and 1-hexene homopolymerizations as well as detailed GPC, DSC, GC, and NMR analyses.