Browsing by Subject "ring-opening polymerization"

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    Ring-Opening Polymerization as a Platform for Tailored Polymers from Isosorbide and Other Renewable Feedstocks
    (2020-10) Saxon, Derek
    To withstand the critical need for plastics, we must innovate how polymers are constructed and deconstructed. Isosorbide and other renewable feedstocks have shown exceptional promise as replacements for commodity plastics. The work in thesis describes ring-opening polymerization as a previously unexplored strategy to synthesize polymers primarily from isosorbide, as well as several other renewable feedstocks. We describe traditional and contemporary approaches to synthesizing polymers from isosorbide along with the current challenges faced (Chapter 1). Initial efforts were aimed at developing polyethers with isosorbide in the backbone through ring-opening polymerization of an annulated isosorbide derivative, ultimately providing control over both the polymer microstructure and macromolecular architecture, enabling cyclic or linear polymers to be targeted (Chapter 2). This work is a stepping-stone for polymerization of complex heterocycles from renewable feedstocks. We then turned our focus to polycarbonate analogs to the poly(meth)acrylates previously developed in our lab (Chapter 3). Specifically, we established a method for the rapid synthesis of chemically recyclable, functional (co)polycarbonates with tailored thermal properties from isosorbide and other renewably derived alcohols. The polycarbonates were then redesigned to exploit industrial waste streams—specifically glycerol and carbon dioxide—to construct the value-added polymer backbone (Chapter 4). Tandem functionalization and ring-opening polymerization is being pursued to afford polycarbonates with 100% renewable content. These efforts may facilitate the development of commercially relevant sustainable polycarbonates with tailored properties that work toward eliminating plastic waste streams.
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    Supporting Data for Ring-Opening Copolymerizations of a CO2-derived δ-Valerolactone with ε-Caprolactone and L-Lactide
    (2024-05-30) Anderson, Ryan A; Fine, Rachel F; Rapagnani, Rachel M; Tonks, Ian A; itonks@umn.edu; Tonks, Ian; University of Minnesota, Tonks group
    These files contain primary data along with associated output from instrumentation supporting all results reported in Anderson et. al. Ring-Opening Copolymerizations of a CO2-derived δ-Valerolactone with ε-Caprolactone and L-Lactide. This work has expanded the synthetic polymer chemistry of the CO2-derived lactone EtVP through ring-opening co-polymerizations with ε-CL and LLA. Polymer properties and microstructures could be tuned through concurrent and se-quential copolymerization strategies, which led to the formation of either block, gradient, or random copolymers. ε-CL block copolymers resulted in semi-crystalline polymers regardless of the molar ratio employed. For LLA, copolymers remained amorphous, and mechanical testing showed improved elasticity relative to PLLA. Furthermore, ε-CL and LLA copolymers could be chemically recycled back to monomer utilizing Sn(Oct)2. While this work lays the foundation for EtVP-based copolymers, investigation into triblocks and other end-of-life options may further improve the potential ap-plications of these CO2-based (co)polymers.
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    Understanding Catalyst Structural Effects on the Ring-Opening Polymerization of Cyclic Esters
    (2020-07) Luke, Anna
    Materials derived from biomass feedstocks are considered sustainable substitutes for some of the petrochemically-derived products used in commercially relevant polymers. One option for synthesizing polymers from these feedstocks involves the ring-opening polymerization (ROP) of cyclic esters, ultimately yielding degradable, aliphatic polyesters. While it is generally accepted that these polymerizations follow a coordination-insertion mechanism, by which the monomer first binds to a Lewis acid before being ring-opened via nucleophilic attack, a deeper and more fundamental mechanistic understanding of these reactions is still needed for improved catalyst design. In this work, ROP reactions are performed via a variety of Zn and Al-based catalysts with modular ligand frameworks, allowing for mechanistic investigation as a function of catalyst structure. In combination with theoretical calculations, results from these experimental works yield a better understanding of how these catalysts operate, allowing for rational catalyst design for the future.