Comparative dielectric studies of segmental mobility in novel polyurethanes

Roussos, M; Konstantopoulou, A; Kalogeras, IM; Kanapitsas, A; Pissis, P; Savelyev, Y; Vassilikou-Dova, A

dc.contributor.author	Roussos, M	en
dc.contributor.author	Konstantopoulou, A	en
dc.contributor.author	Kalogeras, IM	en
dc.contributor.author	Kanapitsas, A	en
dc.contributor.author	Pissis, P	en
dc.contributor.author	Savelyev, Y	en
dc.contributor.author	Vassilikou-Dova, A	en
dc.date.accessioned	2014-03-01T01:53:56Z
dc.date.available	2014-03-01T01:53:56Z
dc.date.issued	2004	en
dc.identifier.issn	1618-7229	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/27138
dc.subject.classification	Polymer Science	en
dc.subject.other	STRUCTURE-PROPERTY RELATIONSHIPS	en
dc.subject.other	CHAIN-END GROUPS	en
dc.subject.other	BLOCK-COPOLYMERS	en
dc.subject.other	POLY(METHYL METHACRYLATE)	en
dc.subject.other	MICROPHASE SEPARATION	en
dc.subject.other	GLASS-TRANSITION	en
dc.subject.other	RELAXATION SPECTROSCOPY	en
dc.subject.other	MOLECULAR MOBILITY	en
dc.subject.other	PHASE-SEPARATION	en
dc.subject.other	BETA-RELAXATION	en
dc.title	Comparative dielectric studies of segmental mobility in novel polyurethanes	en
heal.type	journalArticle	en
heal.identifier.secondary	042	en
heal.language	English	en
heal.publicationDate	2004	en
heal.abstract	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 a 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 hard-segment microdomains. The results obtained by DRS and TSDC were in good agreement with each other and in reasonable agreement with results for the micro-phase 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 a 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.	en
heal.publisher	EUROPEAN POLYMER FEDERATION	en
heal.journalName	E-POLYMERS	en
dc.identifier.isi	ISI:000222358900001	en