Water effects in polyurethane block copolymers

Pissis, P; Apekis, L; Christodoulides, C; Niaounakis, M; Kyritsis, A; Nedbal, J

dc.contributor.author	Pissis, P	en
dc.contributor.author	Apekis, L	en
dc.contributor.author	Christodoulides, C	en
dc.contributor.author	Niaounakis, M	en
dc.contributor.author	Kyritsis, A	en
dc.contributor.author	Nedbal, J	en
dc.date.accessioned	2014-03-01T01:12:32Z
dc.date.available	2014-03-01T01:12:32Z
dc.date.issued	1996	en
dc.identifier.issn	0887-6266	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/12114
dc.subject	Dielectric relaxation spectroscopy	en
dc.subject	Diffusion	en
dc.subject	Plasticization	en
dc.subject	Polyurethane block copolymers	en
dc.subject	Water sorption	en
dc.subject.classification	Polymer Science	en
dc.subject.other	Adsorption isotherms	en
dc.subject.other	Dielectric relaxation	en
dc.subject.other	Differential scanning calorimetry	en
dc.subject.other	Diffusion	en
dc.subject.other	Glass transition	en
dc.subject.other	Hydration	en
dc.subject.other	Plasticizers	en
dc.subject.other	Polarization	en
dc.subject.other	Polyurethanes	en
dc.subject.other	Saturation (materials composition)	en
dc.subject.other	Temperature	en
dc.subject.other	Water absorption	en
dc.subject.other	Dielectric relaxation spectroscopy	en
dc.subject.other	Dynamic sorption isotherm measurement	en
dc.subject.other	Equilibrium isotherm measurement	en
dc.subject.other	Thermally stimulated depolarization currents	en
dc.subject.other	Water sorption	en
dc.subject.other	Weight fraction	en
dc.subject.other	Block copolymers	en
dc.title	Water effects in polyurethane block copolymers	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/(SICI)1099-0488(19960715)34:9<1529::AID-POLB1>3.0.CO;2-G	en
heal.identifier.secondary	http://dx.doi.org/10.1002/(SICI)1099-0488(19960715)34:9<1529::AID-POLB1>3.0.CO;2-G	en
heal.language	English	en
heal.publicationDate	1996	en
heal.abstract	Equilibrium and dynamic sorption isotherm measurements, differential scanning calorimetry (DSC) measurements, and, mainly, dielectric relaxation spectroscopy (DRS) measurements by means of the thermally stimulated depolarization currents (TSDC) method were used to investigate the hydration properties of linear segmented polyurethane copolymers. Three types of samples were investigated with various fractions of hard and soft block segments. They were based on polyethylene adipate (PEA), 4,4'-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BDO). At 20 degrees C the water content h of the samples at various values of relative humidity rh increases in proportion to the weight fraction of soft block segments phase. At saturation (rh = 100%) the ratio of sorbed water molecules to polar carbonyl polyester groups is 0.13. At saturation at 20 degrees C there is no fraction of freezable water. The glass transition temperature, T-g, measured by DSC and by TSDC, shifts to lower temperature with increasing h by about 8-10 K at saturation at 20 degrees C. A dielectric relaxation mechanism related to interfacial polarization in the phase-separated morphology is also plasticized by water in a way similar to that observed for the main (alpha) relaxation. (C) 1996 John Wiley & Sons, Inc.	en
heal.publisher	JOHN WILEY & SONS INC	en
heal.journalName	Journal of Polymer Science, Part B: Polymer Physics	en
dc.identifier.doi	10.1002/(SICI)1099-0488(19960715)34:9<1529::AID-POLB1>3.0.CO;2-G	en
dc.identifier.isi	ISI:A1996UT32600005	en
dc.identifier.volume	34	en
dc.identifier.issue	9	en
dc.identifier.spage	1529	en
dc.identifier.epage	1539	en