Molecular Dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase Separation

  • For the first time, dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbones and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl) is reported. Generally, this class of polymers has some potential for applications in the field of gas separation membranes. Two dielectrically active processes are observed at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter is related to the glassy dynamics of the flexible -Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain rich and backbone rich domains. This is confirmed through temperature modulated DSC measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time usingFor the first time, dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbones and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl) is reported. Generally, this class of polymers has some potential for applications in the field of gas separation membranes. Two dielectrically active processes are observed at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter is related to the glassy dynamics of the flexible -Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain rich and backbone rich domains. This is confirmed through temperature modulated DSC measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time using Fast Scanning Calorimetry employing both fast heating and cooling rates. This is complimented with scattering experiments that show how the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all poly(tricyclononenes) with -Si(OR)3 side groups, which is interpreted in terms of a percolation model.zeige mehrzeige weniger

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Autor*innen:Mohamed Aejaz Kolmangadi, Paulina SzymoniakORCiD, Glen Jacob SmalesORCiD, D. Alentiev, M. Bermeshev, Martin BöhningORCiD, Andreas SchönhalsORCiD
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Macromolecules
Jahr der Erstveröffentlichung:2020
Organisationseinheit der BAM:6 Materialchemie
6 Materialchemie / 6.5 Synthese und Streuverfahren nanostrukturierter Materialien
6 Materialchemie / 6.6 Physik und chemische Analytik der Polymere
7 Bauwerkssicherheit
7 Bauwerkssicherheit / 7.5 Technische Eigenschaften von Polymerwerkstoffen
Verlag:ACS
Jahrgang/Band:53
Ausgabe/Heft:17
Erste Seite:7410
Letzte Seite:7419
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten
Freie Schlagwörter:Advanced calorimetry; Broadband Dielectric Spectrscopy; Polynorbornenes
Themenfelder/Aktivitätsfelder der BAM:Chemie und Prozesstechnik
Material
DOI:10.1021/acs.macromol.0c01450
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:10.09.2020
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:12.10.2020
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