Date of Award
1-24-2022
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
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.
Language
English (en)
Chair and Committee
William Tolman
Committee Members
Richard Mabbs
Recommended Citation
Peterson, Appie A., "Aluminum Catalysts in the Ring-Opening Polymerizations of Cyclic Esters" (2022). Arts & Sciences Electronic Theses and Dissertations. 3253.
https://openscholarship.wustl.edu/art_sci_etds/3253