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Molecular Mobility and Physical aging of SuperGlassy Polymers for Gas Separation Membranes as revealed by Dielectric Spectroscopy

  • Polymeric membranes represent a cost- and energy efficient solution for gas separation. Recently superglassy polymers with high free volume outperform many conventional dense polymers in terms of gas permeability and selectivity. However, such materials with a high fractional free volume (FFV) are prone to pronounced physical aging. The initial microporous structures approach a denser state via local chain rearrangements which results in a dramatic reduction in the gas permeability. For the first time, dielectric spectroscopy with state-of-the-art high-resolution analyzers was employed to investigate the molecular mobility and physical aging of two representative groups of superglassy polymers: PIMs (PIM-1 & PIM-EA-TB) and Si-containing polynobornenes (PTCNSi1 & PTCNSi2). The dielectric behavior of the solution-cast polymeric films was measured by isothermal frequency scans during the different heating cycles in a broad temperature range. Structural relaxation of the films was observedPolymeric membranes represent a cost- and energy efficient solution for gas separation. Recently superglassy polymers with high free volume outperform many conventional dense polymers in terms of gas permeability and selectivity. However, such materials with a high fractional free volume (FFV) are prone to pronounced physical aging. The initial microporous structures approach a denser state via local chain rearrangements which results in a dramatic reduction in the gas permeability. For the first time, dielectric spectroscopy with state-of-the-art high-resolution analyzers was employed to investigate the molecular mobility and physical aging of two representative groups of superglassy polymers: PIMs (PIM-1 & PIM-EA-TB) and Si-containing polynobornenes (PTCNSi1 & PTCNSi2). The dielectric behavior of the solution-cast polymeric films was measured by isothermal frequency scans during the different heating cycles in a broad temperature range. Structural relaxation of the films was observed during the measurements. Multiple dielectric processes following Arrhenius behavior were observed for all the investigated polymers. Moreover, they all showed conductivity in the glassy state. The significant increase in the conductivity with increasing temperature especially for PIMs is explained in terms of the formation of local intermolecular agglomerated structures due to interaction of π-electrons in aromatic moieties of the polymer backbone.zeige mehrzeige weniger

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Metadaten
Autor*innen:Huajie YinORCiD
Koautor*innen:N. Konnertz, Martin Böhning, Andreas Schönhals
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2017
DDC-Klassifikation:Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik
Freie Schlagwörter:Broadband dielectric spectroscopy; Gas separation; Membranes; Molecular mobility; Physical aging
Veranstaltung:8th International Conference on Advanced Fibers and Polymer Materials
Veranstaltungsort:Shanghai, China
Beginndatum der Veranstaltung:08.10.2017
Enddatum der Veranstaltung:10.10.2017
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:14.11.2017
Referierte Publikation:Nein
Eingeladener Vortrag:Nein
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