Glass transition and segmental dynamics in poly(dimethylsiloxane)/silica nanocomposites studied by various techniques

Fragiadakis, D; Pissis, P

dc.contributor.author	Fragiadakis, D	en
dc.contributor.author	Pissis, P	en
dc.date.accessioned	2014-03-01T01:26:24Z
dc.date.available	2014-03-01T01:26:24Z
dc.date.issued	2007	en
dc.identifier.issn	0022-3093	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18062
dc.subject	64.70.Pf	en
dc.subject	77.22.Gm	en
dc.subject	82.35.Np	en
dc.subject	Calorimetry	en
dc.subject	Dielectric properties	en
dc.subject	Glass transition	en
dc.subject	Nanocomposites	en
dc.subject	Polymers and organics	en
dc.subject	relaxation, electric modulus	en
dc.subject	Silica	en
dc.subject.classification	Materials Science, Ceramics	en
dc.subject.classification	Materials Science, Multidisciplinary	en
dc.subject.other	Dielectric properties	en
dc.subject.other	Dielectric relaxation	en
dc.subject.other	Dielectric spectroscopy	en
dc.subject.other	Differential scanning calorimetry	en
dc.subject.other	Glass transition	en
dc.subject.other	Molecular dynamics	en
dc.subject.other	Nanocomposites	en
dc.subject.other	Silica	en
dc.subject.other	Sol-gel process	en
dc.subject.other	Electric modulus	en
dc.subject.other	Segmental dynamics	en
dc.subject.other	Silica nanoparticles	en
dc.subject.other	Thermally stimulated depolarization currents	en
dc.subject.other	Polydimethylsiloxane	en
dc.title	Glass transition and segmental dynamics in poly(dimethylsiloxane)/silica nanocomposites studied by various techniques	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.jnoncrysol.2007.05.183	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.jnoncrysol.2007.05.183	en
heal.language	English	en
heal.publicationDate	2007	en
heal.abstract	We report new results on segmental dynamics and glass transition in a series of poly(dimethylsiloxane) networks filled with silica nanoparticles prepared by sol-gel techniques, obtained by differential scanning calorimetry (DSC), thermally stimulated depolarization currents (TSDC), broadband dielectric relaxation spectroscopy (DRS) and dynamic mechanical analysis (DMA). The nanocomposites are characterized by a fine dispersion of 10 nm silica particles and hydrogen bonding polymer/filler interactions. The first three techniques indicate, in agreement with each other, that a fraction of polymer in an interfacial layer around the silica particles with a thickness of 2-3 nm shows modified dynamics. The DSC data, in particular measurements of heat capacity jump at T-g, are analyzed in terms of immobilized polymer in the interfacial layer. The dielectric TSDC and DRS data are analyzed in terms of slower dynamics in the interfacial layer as compared to bulk dynamics. We employ a special version of TSDC, the so-called thermal sampling (TS) technique, and provide experimental evidence for a continuous distribution of glass transition temperatures (T-g) and molecular mobility of the polymer in the interfacial layer, which is consistent with the DRS data. Finally, DMA results show a moderate slowing down of segmental dynamics of the whole polymer matrix (increase of glass transition temperature by about 10 K as compared to the pure matrix). (c) 2007 Elsevier B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Journal of Non-Crystalline Solids	en
dc.identifier.doi	10.1016/j.jnoncrysol.2007.05.183	en
dc.identifier.isi	ISI:000251476300020	en
dc.identifier.volume	353	en
dc.identifier.issue	47-51	en
dc.identifier.spage	4344	en
dc.identifier.epage	4352	en