Golder, MatthewPomfret, Meredith2024-10-162024-10-162024Pomfret_washington_0250E_27518.pdfhttps://hdl.handle.net/1773/52438Thesis (Ph.D.)--University of Washington, 2024Polymer architecture dictates the physical properties and therefore the function of a material. Consequently, structural changes in the polymer backbone have drastic influences on macromolecular physical properties. For example, rigid monomer units create stiff polymer chains with excellent thermal and mechanical properties, at the expense of processability. Meanwhile, flexible monomer units like ethylenes and siloxanes create soft, flexible plastics at the expense of thermal and mechanical robustness. Synthesizing polymers with novel architectures can overcome these challenges by creating materials with a unique set of properties and thus eliminating the trade-off between chain flexibility and desirable macromolecular physical properties. Detailed within this thesis are our reports of modulating backbone architecture of linear polymers using fluxional monomer units. Additionally, we explore the synthesis of cyclic polymer architectures using ring expansion metathesis polymerization (REMP) through catalyst design and mechanistic studies. First, we demonstrate that small molecule pericyclic rearrangements in bullvalene monomer units creates stochastic kinks in an otherwise rigid polymer backbone. This unique chain architecture results in lower hydrodynamic volumes and decreased thermal transitions. Next, we investigate a different, but also compact, polymer architecture by investigating the REMP mechanism and the role of chain transfer events in molecular weight evolution and size of the cyclic polymer products. Finally, we investigate the structure-function relationship of REMP catalysts by modifying tether length and studying the resulting polymerization profiles. Tether length was found to have a significant effect on REMP rate, providing further understanding on these processes. Through these studies, we elucidate valuable information on REMP polymerization profiles and catalyst behavior, providing insight for future optimization of the synthesis of cyclic polymers.application/pdfen-USnoneChemistryChemistryThesis