Polyurethane-POSS hybrids: Molecular dynamics studies

Raftopoulos, KN; Pandis, Ch; Apekis, L; Pissis, P; Janowski, B; Pielichowski, K; Jaczewska, J

dc.contributor.author	Raftopoulos, KN	en
dc.contributor.author	Pandis, Ch	en
dc.contributor.author	Apekis, L	en
dc.contributor.author	Pissis, P	en
dc.contributor.author	Janowski, B	en
dc.contributor.author	Pielichowski, K	en
dc.contributor.author	Jaczewska, J	en
dc.date.accessioned	2014-03-01T01:34:18Z
dc.date.available	2014-03-01T01:34:18Z
dc.date.issued	2010	en
dc.identifier.issn	0032-3861	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/20689
dc.subject	Dielectric spectroscopy	en
dc.subject	Polymer dynamics	en
dc.subject	Polyurethane-POSS nanocomposites	en
dc.subject.classification	Polymer Science	en
dc.subject.other	AFM	en
dc.subject.other	Broadband dielectric relaxation spectroscopy	en
dc.subject.other	Butanediol	en
dc.subject.other	Chain extenders	en
dc.subject.other	Crystallinities	en
dc.subject.other	Dielectric strengths	en
dc.subject.other	Dynamic glass transition	en
dc.subject.other	Extended structures	en
dc.subject.other	Glass transition temperature	en
dc.subject.other	Hard components	en
dc.subject.other	Main chains	en
dc.subject.other	matrix	en
dc.subject.other	Micro-domains	en
dc.subject.other	Molecular mobility	en
dc.subject.other	Phenylisocyanate	en
dc.subject.other	Poly(tetramethylene glycol)	en
dc.subject.other	Polymer dynamics	en
dc.subject.other	POSS hybrids	en
dc.subject.other	Secondary relaxations	en
dc.subject.other	Segmental dynamics	en
dc.subject.other	Segmental relaxation	en
dc.subject.other	Soft components	en
dc.subject.other	Thermally stimulated depolarization currents	en
dc.subject.other	Weight fractions	en
dc.subject.other	Dielectric devices	en
dc.subject.other	Dielectric spectroscopy	en
dc.subject.other	Differential scanning calorimetry	en
dc.subject.other	Dynamics	en
dc.subject.other	Glass	en
dc.subject.other	Glycols	en
dc.subject.other	Hybrid materials	en
dc.subject.other	Molecular dynamics	en
dc.subject.other	Nanocomposites	en
dc.subject.other	Reconnaissance aircraft	en
dc.subject.other	Glass transition	en
dc.subject.other	crystallinity	en
dc.subject.other	dielectric property	en
dc.subject.other	polymer blend	en
dc.subject.other	polyurethane	en
dc.subject.other	synthesis	en
dc.title	Polyurethane-POSS hybrids: Molecular dynamics studies	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.polymer.2009.11.067	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.polymer.2009.11.067	en
heal.language	English	en
heal.publicationDate	2010	en
heal.abstract	A series of hybrid polyurethane-POSS materials have been synthesized on the basis of poly(tetramethylene glycol) (Terathane 1400 (R)) as soft component, 4,4'-methylenebis(phenylisocyanate) (MDI) as hard component, and 1,4-butanediol as chain extender. POSS particles properly modified have been tethered on the main chain by substitution of the chain extender to weight fractions up to 10%. AFM measurements indicate the formation of POSS crystallites in the PU matrix, extended structures at low POSS content and more regular, smaller structures at higher POSS content. A detailed investigation of molecular mobility by means of Differential Scanning Calorimetry (DSC), Thermally Stimulated Depolarization Currents (TSDC) and, mainly, Broadband Dielectric Relaxation Spectroscopy (DRS) has been conducted in all samples of the series and in addition in neat Terathane, as reference. Four relaxations have been studied in detail: two secondary relaxations gamma and beta, the segmental alpha relaxation (dynamic glass transition) and an alpha' relaxation slower than alpha associated with crystallinity in neat Terathane and with the presence of hard microdomains in the polyurethane and the hybrids. Secondary relaxations remain unaffected by POSS. The glass transition temperature rises by a few degrees and, in consistency with that, segmental dynamics slightly slows down with increasing POSS content. In addition, the dielectric strength of the segmental relaxation decreases with increasing POSS content, suggesting that a fraction of polymer is immobilized, making no contribution to the relaxation. These results are discussed in relation to morphology. (C) 2009 Elsevier Ltd. All rights reserved.	en
heal.publisher	ELSEVIER SCI LTD	en
heal.journalName	Polymer	en
dc.identifier.doi	10.1016/j.polymer.2009.11.067	en
dc.identifier.isi	ISI:000274281200016	en
dc.identifier.volume	51	en
dc.identifier.issue	3	en
dc.identifier.spage	709	en
dc.identifier.epage	718	en