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Zachary P. Smith - One of the best experts on this subject based on the ideXlab platform.

  • Free volume manipulation of a 6FDA-HAB polyimide using a solid-State Protection/deProtection strategy
    Polymer, 2021
    Co-Authors: Sharon Lin, Taigyu Joo, Francesco M. Benedetti, Laura C. Chen, Katherine Mizrahi Rodriguez, Qihui Qian, Cara M. Doherty, Zachary P. Smith
    Abstract:

    Abstract Tert-butoxycarbonyl (t-BOC) is a thermally labile moiety that can be used to protect hydroxyl groups on polymers. In this study, t-BOC was appended onto a polyimide consisting of 2,2′-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 3,3′-dihydroxy-4,4′-diamino-biphenyl (HAB), after which the polymer was formed into self-standing films. Solid-State thermal treatments were performed to systematically remove t-BOC moieties to alter the physical packing structure and concomitant gas transport properties of the polymer. Despite performing deProtection reactions well below the glass transition temperature of 6FDA-HAB (~300 °C), this free volume manipulation (FVM) approach produced only subtle differences in polymer density, fractional free volume, average free volume element size, and gas transport properties relative to the unprotected polymer. While these findings suggest that thermally removing covalently bound functional groups from polymer films can be used to manipulate free volume and gas transport performance for glassy polymers, more robust polymer systems than linear polyimides are required to preserve the nascent free volume architecture generated from this approach.

  • free volume manipulation of a 6fda hab polyimide using a solid State Protection deProtection strategy
    Polymer, 2020
    Co-Authors: Sharon Lin, Taigyu Joo, Francesco M. Benedetti, Laura C. Chen, Katherine Mizrahi Rodriguez, Qihui Qian, Cara M. Doherty, Zachary P. Smith
    Abstract:

    Abstract Tert-butoxycarbonyl (t-BOC) is a thermally labile moiety that can be used to protect hydroxyl groups on polymers. In this study, t-BOC was appended onto a polyimide consisting of 2,2′-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 3,3′-dihydroxy-4,4′-diamino-biphenyl (HAB), after which the polymer was formed into self-standing films. Solid-State thermal treatments were performed to systematically remove t-BOC moieties to alter the physical packing structure and concomitant gas transport properties of the polymer. Despite performing deProtection reactions well below the glass transition temperature of 6FDA-HAB (~300 °C), this free volume manipulation (FVM) approach produced only subtle differences in polymer density, fractional free volume, average free volume element size, and gas transport properties relative to the unprotected polymer. While these findings suggest that thermally removing covalently bound functional groups from polymer films can be used to manipulate free volume and gas transport performance for glassy polymers, more robust polymer systems than linear polyimides are required to preserve the nascent free volume architecture generated from this approach.

M. Suhail Zubairy - One of the best experts on this subject based on the ideXlab platform.

Steffen Bunzel - One of the best experts on this subject based on the ideXlab platform.

  • Shipboard Solid-State Protection: Overview and Applications
    IEEE Electrification Magazine, 2013
    Co-Authors: Rich Schmerda, Rodney Clark, Dan Nowak, Rob Cuzner, Steffen Bunzel
    Abstract:

    This article presents an overview of the present art of low-voltage (LV) dc power distribution system Protection using solid-State protective devices (SSPDs). It describes how IGBTand IGCT-based SSPDs are constructed and how the important feature of galvanic isolation can be included in them. The article outlines the advantages of SSPDs, which include reduced fault-current level, greatly reduced current interruption time, limitation of arc-flash energy, improved acoustic performance, and reduced maintenance. It also demonstrates protective coordination using three of these solid-State circuit breakers and discusses new paradigms to consider. Test results are presented validating the use of restraint signals to aid in proper protective coordination in a generic three-level power distribution system. The article also shows test results for two paralleled SSPD building blocks used to make higher-current-rated solid-State circuit breakers, showing very good dynamic current sharing.

Sharon Lin - One of the best experts on this subject based on the ideXlab platform.

  • Free volume manipulation of a 6FDA-HAB polyimide using a solid-State Protection/deProtection strategy
    Polymer, 2021
    Co-Authors: Sharon Lin, Taigyu Joo, Francesco M. Benedetti, Laura C. Chen, Katherine Mizrahi Rodriguez, Qihui Qian, Cara M. Doherty, Zachary P. Smith
    Abstract:

    Abstract Tert-butoxycarbonyl (t-BOC) is a thermally labile moiety that can be used to protect hydroxyl groups on polymers. In this study, t-BOC was appended onto a polyimide consisting of 2,2′-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 3,3′-dihydroxy-4,4′-diamino-biphenyl (HAB), after which the polymer was formed into self-standing films. Solid-State thermal treatments were performed to systematically remove t-BOC moieties to alter the physical packing structure and concomitant gas transport properties of the polymer. Despite performing deProtection reactions well below the glass transition temperature of 6FDA-HAB (~300 °C), this free volume manipulation (FVM) approach produced only subtle differences in polymer density, fractional free volume, average free volume element size, and gas transport properties relative to the unprotected polymer. While these findings suggest that thermally removing covalently bound functional groups from polymer films can be used to manipulate free volume and gas transport performance for glassy polymers, more robust polymer systems than linear polyimides are required to preserve the nascent free volume architecture generated from this approach.

  • free volume manipulation of a 6fda hab polyimide using a solid State Protection deProtection strategy
    Polymer, 2020
    Co-Authors: Sharon Lin, Taigyu Joo, Francesco M. Benedetti, Laura C. Chen, Katherine Mizrahi Rodriguez, Qihui Qian, Cara M. Doherty, Zachary P. Smith
    Abstract:

    Abstract Tert-butoxycarbonyl (t-BOC) is a thermally labile moiety that can be used to protect hydroxyl groups on polymers. In this study, t-BOC was appended onto a polyimide consisting of 2,2′-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 3,3′-dihydroxy-4,4′-diamino-biphenyl (HAB), after which the polymer was formed into self-standing films. Solid-State thermal treatments were performed to systematically remove t-BOC moieties to alter the physical packing structure and concomitant gas transport properties of the polymer. Despite performing deProtection reactions well below the glass transition temperature of 6FDA-HAB (~300 °C), this free volume manipulation (FVM) approach produced only subtle differences in polymer density, fractional free volume, average free volume element size, and gas transport properties relative to the unprotected polymer. While these findings suggest that thermally removing covalently bound functional groups from polymer films can be used to manipulate free volume and gas transport performance for glassy polymers, more robust polymer systems than linear polyimides are required to preserve the nascent free volume architecture generated from this approach.

Rich Schmerda - One of the best experts on this subject based on the ideXlab platform.

  • Shipboard Solid-State Protection: Overview and Applications
    IEEE Electrification Magazine, 2013
    Co-Authors: Rich Schmerda, Rodney Clark, Dan Nowak, Rob Cuzner, Steffen Bunzel
    Abstract:

    This article presents an overview of the present art of low-voltage (LV) dc power distribution system Protection using solid-State protective devices (SSPDs). It describes how IGBTand IGCT-based SSPDs are constructed and how the important feature of galvanic isolation can be included in them. The article outlines the advantages of SSPDs, which include reduced fault-current level, greatly reduced current interruption time, limitation of arc-flash energy, improved acoustic performance, and reduced maintenance. It also demonstrates protective coordination using three of these solid-State circuit breakers and discusses new paradigms to consider. Test results are presented validating the use of restraint signals to aid in proper protective coordination in a generic three-level power distribution system. The article also shows test results for two paralleled SSPD building blocks used to make higher-current-rated solid-State circuit breakers, showing very good dynamic current sharing.