caa a22 4500 378903349 CHVBK 20180305123523.0 cr unu---uuuuu 161128e20041201xx s 000 0 eng 10.1515/epoly.2004.4.1.441 doi (NATIONALLICENCE)gruyter-10.1515/epoly.2004.4.1.441 Comparative dielectric studies of segmental mobility in novel polyurethanes [Elektronische Daten] [Michalis Roussos, Anna Konstantopoulou, Ioannis M. Kalogeras, Athanassios Kanapitsas, Polycarpos Pissis, Yuri Savelyev, Aglaia Vassilikou-Dova] Molecular dynamics in selected novel linear/low-branched polyurethanes (PUs), based on oligo(oxytetramethylene glycol), 4,4'-diphenylmethanediisocyanate (MDI) or 2,6-toluenediisocyanate (TDI), and unsymmetrical dimethylhydrazine (I) and a derivative of that (II) as chain extenders (CE), were studied by dielectric techniques. Special attention was paid to the investigation of the α relaxation, associated to the glass transition, by dielectric relaxation spectroscopy (DRS) and thermally stimulated depolarization currents (TSDC). The TSDC method was used to study the interfacial Maxwell-Wagner-Sillars (MWS) relaxation, related to the accumulation of charges at the interfaces between soft-segment and hardsegment microdomains. The results obtained by DRS and TSDC were in good agreement with each other and in reasonable agreement with results for the microphase separation (MS) obtained by small-angle X-ray scattering and differential scanning calorimetry. TSDC proved to be an attractive complementary technique to DRS for the study of MS in PUs. The results suggest that the position of the MWS band, as well as its separation from the α band, is a good measure of the degree of MS. As regards the PUs studied here, the degree of MS enhances by increasing the mole ratio of CE, and by replacing MDI by TDI or CE I by CE II. © 2013 by Walter de Gruyter GmbH & Co. Roussos Michalis Department of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos, Greece aut Konstantopoulou Anna Department of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos, Greece aut Kalogeras Ioannis M. Department of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos, Greece aut Kanapitsas Athanassios Department of Physics, National Technical University of Athens, Zografou Campus, 157 80 Zografos, Greece aut Pissis Polycarpos Department of Physics, National Technical University of Athens, Zografou Campus, 157 80 Zografos, Greece aut Savelyev Yuri Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, Harkivske shose 48, 02160 Kyiv, Ukraine aut Vassilikou-Dova Aglaia Department of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos, Greece aut e-Polymers De Gruyter 4/1(2004-12-01), 441-454 2197-4586 4:1<441 2004 4 epoly https://doi.org/10.1515/epoly.2004.4.1.441 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/epoly.2004.4.1.441 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Roussos Michalis Department of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos, Greece aut NATIONALLICENCE 700 1- Konstantopoulou Anna Department of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos, Greece aut NATIONALLICENCE 700 1- Kalogeras Ioannis M. Department of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos, Greece aut NATIONALLICENCE 700 1- Kanapitsas Athanassios Department of Physics, National Technical University of Athens, Zografou Campus, 157 80 Zografos, Greece aut NATIONALLICENCE 700 1- Pissis Polycarpos Department of Physics, National Technical University of Athens, Zografou Campus, 157 80 Zografos, Greece aut NATIONALLICENCE 700 1- Savelyev Yuri Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, Harkivske shose 48, 02160 Kyiv, Ukraine aut NATIONALLICENCE 700 1- Vassilikou-Dova Aglaia Department of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos, Greece aut NATIONALLICENCE 773 0- e-Polymers De Gruyter 4/1(2004-12-01), 441-454 2197-4586 4:1<441 2004 4 epoly CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter