Browsing by Author "Jang, Yoon-Jung"

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    Supporting data for Chemically Recyclable Linear and Branched Polyethylenes Synthesized from Stoichiometrically Self-balanced Telechelic Polyethylenes
    (2024-02-01) Jang, Yoon-Jung; Nguyen, Sam; 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 of the referenced paper.
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    Supporting Data for Ductile Gas Barrier Poly(ester-amide)s Derived from Glycolide
    (2022-06-21) Jang, Yoon-Jung; Sangroniz, Leire; Hillmyer, Marc; hillmyer@umn.edu; Hillmyer, Marc
    The development of promising sustainable gas barrier materials, such as polyglycolide, poly(L-lactide), and poly(ethylene 2,5-furandicarboxylate) is an important alternative strategy to traditional plastics used for packaging where low gas permeability is beneficial. However, high degrees of crystallinity in these materials can lead to undesirably low material toughness. We report poly(ester-amide)s derived from glycolide and diamines exhibiting both high toughness and desirable gas barrier properties. These sustainable poly(ester-amide)s were synthesized from glycolide-derived diamidodiols and diacids. To understand structure-property relationships of poly(ester-amide)s, polymers with different numbers of methylene groups were compared with respect to thermal, mechanical, and gas barrier properties. As the number of methylene groups between ester groups increased, the melting temperature decreased and oxygen permeability increased in the even numbered methylene group series. We also found that they are readily degradable under neutral, acidic, and basic hydrolytic conditions. These high performance poly(ester-amide)s are promising sustainable alternatives to conventional gas barrier materials.
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    Supporting data for Synthesis, microstructure, and properties of high molar mass polyglycolide copolymers with isolated methyl defects
    (2021-06-15) Altay, Esra; Jang, Yoon-Jung; Kua, Xiang Qi; Hillmyer, Marc; hillmyer@umn.edu; Hillmyer, Marc; University of Minnesota, Hillmyer Lab, Department of Chemistry
    An efficient, fast and reliable method for the synthesis of high molar mass polyglycolide (PGA) in bulk using bismuth (III) subsalicylate through ring-opening transesterification polymerization is described.The difference between the crystallization (Tc ≈ 180 °C) / degradation (Td ≈ 245 °C) temperatures and the melting temperature (Tm ≈ 222 °C) significantly impacts the ability to melt process PGA homopolymer. To expand these windows, the effect of copolymer microstructure differences through incorporation of methyl groups in pairs using lactide or isolated using methyl glycolide (10% methyl) as comonomers on the thermal, mechanical and barrier properties were studied. Structures of copolymers were characterized by Nuclear Magnetic Resonance (1H and 13C NMR) spectroscopies. Films of copolymers were obtained, and the microstructural and physical properties were analyzed. PGA homopolymers exhibited approximately 30 °C difference between Tm and Tc, which increased to 50 °C by incorporating up to 10% methyl groups in the chain while maintaining overall thermal stability. Oxygen and water vapor permeation values of solvent cast non-oriented films of PGA homopolymers were found to be 4.6 (cc.mil.m-2.d-1.atm-1) and 2.6 (g.mil.m-2.d-1.atm-1), respectively. Different methyl distributions in the copolymer sequence, provided through either lactide or methyl glycolide impacted the resulting barrier properties. At 10% methyl insertion using lactide as a comonomer significantly increased both O2 (32 cc.mil.m-2.d-1.atm-1) and water vapor (12 g.mil.m-2.d-1.atm-1) permeation. However, when methyl glycolide was utilized for methyl insertion at 10% Me content, excellent barrier properties for both O2 (2.9 cc.mil.m-2.d-1.atm-1) and water vapor (1.0 g.mil.m-2.d-1.atm-1) were achieved.