DEPOLARIZATION THERMOCURRENT STUDIES IN POLY(HYDROXYETHYL ACRYLATE) WATER HYDROGELS

KYRITSIS, A; PISSIS, P; RIBELLES, JLG; PRADAS, MM

dc.contributor.author	KYRITSIS, A	en
dc.contributor.author	PISSIS, P	en
dc.contributor.author	RIBELLES, JLG	en
dc.contributor.author	PRADAS, MM	en
dc.date.accessioned	2014-03-01T01:09:50Z
dc.date.available	2014-03-01T01:09:50Z
dc.date.issued	1994	en
dc.identifier.issn	0887-6266	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/11197
dc.subject	HYDROGELS	en
dc.subject	WATER IN POLY(HYDROXYETHYL ACRYLATE)	en
dc.subject	DIELECTRIC RELAXATION	en
dc.subject	THERMALLY STIMULATED DEPOLARIZATION CURRENTS (TSDC)	en
dc.subject	GLASS TRANSITION	en
dc.subject	SPACE CHARGE POLARIZATION	en
dc.subject.classification	Polymer Science	en
dc.subject.other	GLASS-TRANSITION TEMPERATURES	en
dc.subject.other	POLY(2-HYDROXYETHYL METHACRYLATE)	en
dc.subject.other	LIQUID TRANSITION	en
dc.subject.other	RELAXATION	en
dc.subject.other	CONDUCTIVITY	en
dc.subject.other	SYSTEMS	en
dc.title	DEPOLARIZATION THERMOCURRENT STUDIES IN POLY(HYDROXYETHYL ACRYLATE) WATER HYDROGELS	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/polb.1994.090320605	en
heal.identifier.secondary	http://dx.doi.org/10.1002/polb.1994.090320605	en
heal.language	English	en
heal.publicationDate	1994	en
heal.abstract	Detailed investigations on the dielectric relaxation mechanisms in poly(hydroxyethyl acrylate) (PHEA), by means of the thermally stimulated depolarization currents (TSDC) method in the temperature range 77-300 K are reported. There is particular interest in the dependence of the dielectric relaxation mechanisms on the water content h, h = 0 - 0.5 w/w, in an attempt to contribute to a better understanding of the physical structure of water in the PHEA hydrogels. We employ thermal sampling (TS) and partial heating (PH) techniques to experimentally analyze the observed complex relaxation processes, due to the secondary (beta(sw)) and the main (alpha) relaxation, into approximately single responses and to determine the spectra of activation energies E(T) at different h values. Measurements with different electrode configurations reveal different aspects of the dynamics of the relaxation mechanisms and allow the distinction between dipolar and conductivity relaxation contributions. It is shown that by means of these techniques we can determine certain temperature characteristics for the alpha relaxation and investigate their dependence on water content. We discuss the relation of these characteristic temperatures to the calorimetric glass transition temperature T(g). (C) 1994 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/polb.1994.090320605	en
dc.identifier.isi	ISI:A1994NB40800005	en
dc.identifier.volume	32	en
dc.identifier.issue	6	en
dc.identifier.spage	1001	en
dc.identifier.epage	1008	en