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.…
Autor*innen: | Huajie YinORCiD |
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Koautor*innen: | N. Konnertz, Martin BöhningORCiD, Andreas SchönhalsORCiD |
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 |