Abstract

The development of bioderived and biodegradable materials is crucial in supplanting our global dependence on fossil fuel derived plastics. An industrially attractive method for synthesizing such polymers is the ring-opening polymerization (ROP) of cyclic monomers sourced from biomass feedstocks. Cyclic esters such as rac-lactide and ε-caprolactone are known to produce aliphatic polyesters via ROP catalyzed by metal alkoxides. The work described herein centers on single-site Aluminum catalysts, which are well-suited for mechanistic studies of ROP due to their convenient rates, production of high molecular weight polymers, and low toxicities. By modulating the steric and electronic substituents of the ligand system, monitoring kinetics of the polymerizations, and characterizing key reactive intermediates, new structure-activity relationships are identified and precedented relationships subverted. Characterization of single ring-opened products of catalyst with lactide by X-ray and spectroscopy have allowed us to identify the basis of stereocontrol in initiation to be the thermodynamic stability of the products, rather than kinetic preference, in two separate systems. This deeper understanding of the source of stereocontrol can guide us to more efficient catalyst design and polymer functionalization.

Committee Chair

William Tolman

Committee Members

Richard Mabbs

Degree

Doctor of Philosophy (PhD)

Author's Department

Chemistry

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

1-24-2022

Language

English (en)

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Chemistry Commons

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