Browsing by Subject "chemical recycling"

Now showing 1 - 3 of 3
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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 Information for Tackling the thermodynamic stability of low-ceiling temperature polymers in the preparation of tough and chemically recyclable thermoplastic polyurethane-urea elastomers
    (2024-05-20) Meyersohn, Marianne S; Block, Alison; Bates, Frank S; Hillmyer, Marc A; hillmyer@umn.edu; Hillmyer, Marc A; University of Minnesota Chemistry Department
    These files contain primary data along with associated output from instrumentation supporting all results reported in the Meyersohn et al, referenced paper. We found: Thermoplastic polyurethane-ureas (TPUUs) from bio-based, depolymerizable polyesters are promising as high-value polymeric materials for a circular economy. We demonstrate the bulk room temperature polymerization of β-methyl-δ-valerolactone (βMVL, Nuvone™) using HCl (as a solution in ether) as a simple acid catalyst to prepare low molar mass polyols. One of the key challenges of poly(β-methyl-δ-valerolactone) (PβMVL) is appreciable equilibrium monomer concentration ([M]eq) at room temperature and above. To mitigate high [M]eq that results from βMVL polymerization we utilize strategies including (i) rapid distillation to rid the polymer of residual monomer, or (ii) sequestration of remaining monomer with diamines to prepare diamidodiols in situ along with the polyol, which can subsequently be used directly as chain extenders in polyurethane urea syntheses, or (iii) the copolymerization of βMVL with lactone monomers that exhibit a higher ceiling temperature to prepare copolymers with varying degrees of crystallinity, improved thermal stability, and reduced residual βMVL content. The aliphatic polyols can then be used as soft-segments in a one-pot approach to prepare TPUUs by reacting with isophorone diisocyanate and chain extending with water. The resulting TPUUs are tough, elastic materials that can be chemically recycled by depolymerization to βMVL, which can be used to prepare new TPUUs with comparable properties.
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    Traditional polymers with nontraditional side-chain functionality: Carboalkoxylated polyvalerolactones and polyisoprenes from malic acid and glucose
    (2019-06) Fahnhorst, Grant
    The compounding environmental effects of non-degradable plastics have attracted increased attention to sustainable polymers. This dissertation is focused on producing polymers from plant-based, renewable feedstocks while also emphasizing novel methods to chemically recycle polymers into valuable fragments. Plant-based feedstocks provide reagents with increased oxidation relative to petroleum and offer the opportunity to access traditional monomers with novel functionality. In this document, approaches to producing biobased monomers in addition to ring-opening transesterification polymerization (ROTEP) are introduced (Chapter 1). After, my research (in Part 1) on the two-step synthesis and ROTEP of 4-carboalkoxyvalerolactones is discussed. The ROTEP of these monomers, which are derived from malic acid, can either provide (i) tough and flexible, semicrystalline polyesters that can be chemically recycled by two independent pathways (Chapter 2 and 4) or (ii) an amorphous, hyperbranched polyester also capable of being chemically recycled (Chapter 3). The architecture of the product polymer is determined by the catalyst used for ROTEP or the position of the carboalkoxy on the lactone ring (Chapter 5). These characteristics are unique to this relatively unstudied family of monomers. In Part 2, anhydromevalonolactone, which can be fermented from glucose, is converted into isoprenecarboxylic acid, isoprenecarboxylate esters, and isoprenecarboxamides. These isoprene derivatives are radically polymerized to provide linear polymers (Chapter 6) or crosslinked superabsorbent hydrogels (Chapter 7). This series of polymers may provide a biobased alternative to polyacrylates.