Upgrading Bioderived Dienes through Cycloaddition and Ring Opening Metathesis Polymerization: Catalyst Development and Materials Design

Abstract

Plastics are ubiquitous in modern society, yet the materials used in production come from fossil fuels. This research aims to access materials from bioderived sources through catalysis, and synthesize carbon-neutral polyolefins with similar properties to those currently on the market. To achieve this goal, the following studies use ring opening metathesis polymerization (ROMP) of eight-membered rings to access bioderived precision polymers. Aiming to synthesize polymers structurally similar to polyethylene and polypropylene, studies focused on ROMP experiments involving substituted octadiene monomers 1,6-dimethyl-1,5-cyclooctadiene (1,6-DMCOD) and 3,7-dimethyl-1,5-cyclooctadiene (3,7-DMCOD). Initial attempts yielded low molecular weight polymers, leading research to focus on monomer purification. Impurities in the 1,6-DMCOD were addressed through selective hydrogenation, resulting in a higher molecular weight polymer following polymerization. Monomer impurities in 3,7-DMCOD were addressed through the design of a more selective catalyst for the [4+4]-cycloaddition of piperylene. ROMP experiments were conducted with the purified monomers in order to determine the effect of the starting materials on polymer properties. A variety of polymers were synthesized, including homopolymers and copolymers, in order to determine the optimal combination of starting materials to synthesize a high molecular weight, robust polymer.