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CPP 4.4: Vortrag
Montag, 16. März 2020, 10:30–10:45, ZEU 255
molecular dynamics of glassy polynorbornenes bearing flexible side substituents: nanophase separation and glass transition — •Mohamed Aejaz Kolmangadi1, Paulina Szymoniak1, Glen Jacob Smales1, Brian Pauw1, Maxim Bermeshev2, Martin Böhning1, and Andreas Schönhals1 — 1Bundesanstalt für Materialforschung und prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany — 2A.V. Topchiev Institute of Petrochemical Synthesis of Russian Academy of Science, Leninskii prospect, 29, 119991 Moscow, Russia
Polynorbornenes are latest among the high-performance polymers in the field of membrane gas separation. Not much has been studied regarding their molecular dynamics till now. In the present work, we report dielectric and calorimetric investigations of series of polynorbornenes with rigid main backbone and flexible (AlkO)3Si side groups with different length (Al = Propyl, Butyl, Octyl, Decyl). Two dielectrically active α and β relaxations observed are assigned to localized fluctuations and segmental relaxation of the flexible side groups of the polymer. A nanophase separation between the main and side chain parts is concluded from the presence of two dynamic glass transitions of the polymer, is confirmed by means of small and wide-angle X-ray scattering. Furthermore, for the first time, the glass transition temperatures of these polymers which are beyond or near to their degradation temperature are determined using Fast Scanning calorimetry employing high heating and cooling rates. The glass transition temperatures of the polymers decrease with increasing length of the alkyl side chain.