Browsing by Author "Meyersohn, Marianne S"

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    Supporting data for "Efficient Polymerization of Methyl-ε-Caprolactone Mixtures to Access Sustainable Aliphatic Polyesters"
    (2020-02-26) Batiste, Derek, C; Meyersohn, Marianne S; Hillmyer, Marc A; Watts, Annabelle; hillmyer@umn.edu; Hillmyer, Marc A; University of Minnesota, Hillmyer Lab, Department of Chemistry
    These files contain primary data along with associated output from instrumentation supporting all results reported in Batiste et. al. "Efficient Polymerization of Methyl-ε-Caprolactone Mixtures to Access Sustainable Aliphatic Polyesters." In Batiste et. al. we found: Aliphatic polyesters are a versatile class of materials that can be sourced from bioderived feedstocks. Poly(γ-methyl-ε-caprolactone) (PγMCL) in particular can be used to make degradable thermoplastic elastomers (TPEs) with outstanding mechanical properties. PγMCL can potentially be manufactured economically from p-cresol, a component of lignin bio oils. A complication is that additional manufacturing processes are necessary to isolate pure cresol isomers. Using mixed feedstocks of cresol isomers to access the corresponding methyl substituted ε-caprolactone (MCL) monomer mixtures would convey economic advantages to sourcing these materials sustainably. Moreover, the use of organocatalysts in lieu of traditional tin-based catalysts averts issues with potential environmental and human toxicity. With these motivations in mind, we explored the ring-opening transesterification polymerization (ROTEP) of MCL mixtures and characterized the molecular, thermal and rheological properties of the resulting copolymers. The molar mass of MCL mixtures that would be obtained from meta- and para-cresol can be readily modulated. The thermal and rheological properties of these statistical co- and terpolymers were at parity with pure PγMCL homopolymer. The use of diphenyl phosphate (DPP) and dimethyl phosphate (DMP) as organocatalysts enabled access to these materials on reasonable polymerization timescales and have potential to improve sustainability in the synthesis of these polyesters.
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    Supporting data for Dynamic Aliphatic Polyester Elastomers Crosslinked with Aliphatic Dianhydrides
    (2023-01-27) Meyersohn, Marianne S; Haque, Farihah M; Hillmyer, Marc A; hillmyer@umn.edu; Hillmyer, Marc, A; University of Minnesota, Department of Chemistry
    These files contain primary data along with associated output from instrumentation supporting all results reported in Meyersohn, M. et. al. "Dynamic Aliphatic Polyester Elastomers Crosslinked with Aliphatic Dianhydrides." In Meyersohn, M. et. al. we found: Chemically crosslinked elastomers are a class of polymeric materials with properties that render them useful as adhesives, sealants, and in other engineering applications. Poly(γ-methyl-ε-caprolactone) (PγMCL) is a hydrolytically degradable and compostable aliphatic polyester that can be biosourced and exhibits competitive mechanical properties to traditional elastomers when chemically crosslinked. A typical limitation of chemically crosslinked elastomers is that they cannot be reprocessed; however, incorporation of dynamic covalent bonds (DCBs) can allow for bonds to reversibly break and reform under an external stimulus, usually heat. In this work we the study dynamic behavior and mechanical properties of PγMCL elastomers synthesized from aliphatic dianhydride crosslinkers. The crosslinked elastomers in this work were synthesized using the commercially available crosslinkers, 1,2,4,5-cyclohexanetetracarboxylic dianhydride (CHDA), and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) and three-arm hydroxy-telechelic PγMCL star polymers. Stress relaxation experiments on the crosslinked networks showed an Arrhenius dependence of viscosity with temperature with an activation energy of 118 ± 8 kJ/mol, which agrees well with the activation energy of the exchange chemistry obtained from small molecule model studies. Dynamic mechanical thermal analysis and rheological experiments confirmed the dynamic nature of the networks and provided insight into the mechanism of exchange (i.e., associative, or dissociative). Tensile testing showed that these materials can exhibit high strains at break and low Young’s moduli, characteristic of soft, strong elastomers. By controlling the exchange chemistry and understanding the effect of macromolecular structure on mechanical properties, we prepared high performing elastomers that can be rapidly reprocessed at moderately elevated temperatures.
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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.