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Effect of aging time on a glass transition of amorphous polymers at heating
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SYSNO ASEP 0429166 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Effect of aging time on a glass transition of amorphous polymers at heating Author(s) Hadač, J. (CZ)
Říha, Pavel (UH-J) SAI, ORCID, RID
Slobodian, P. (CZ)
Saha, P. (CZ)
Kubát, J. (SE)Source Title Chemické listy. - : Česká společnost chemická - ISSN 0009-2770
Roč. 108, special issue 1 (2014), s. 59-65Number of pages 7 s. Publication form Print - P Language eng - English Country CZ - Czech Republic Keywords physical aging ; glass transition ; PMMA ; relaxation function Subject RIV BK - Fluid Dynamics Institutional support UH-J - RVO:67985874 CEZ AV0Z20600510 - UH-J (2005-2011) UT WOS 000344829700012 EID SCOPUS 84901818984 Annotation The relaxation and consolidation processes accompanying the glass transition are linked in this paper with an induction mechanism introducing a cooperative character of relaxation into those processes. The induction mechanism supplements the proposition underlying the internal energy material clock used in a recently developed thermodynamically consistent non-linear viscoelastic theory modeling thermal and mechanical behavior of amorphous polymers in the glass transition range1,2. The mechanism is introduced into the constitutive theory framework where it replaces the stretched exponential relaxation functions. The proposed modification is used to describe the dilatometric behavior of PMMA during heating from the glassy state after varying aging times. The modified theoretical approach is found to produce a fairly good description of the peaks in thermal expansivity, both with regard to their intensity and position along the temperature axis. The length of the aging period in the glassy state is found to affect the material time scale while the relaxation functions are unchanged Workplace Institute of Hydrodynamics Contact Soňa Hnilicová, hnilicova@ih.cas.cz, Tel.: 233 109 003 Year of Publishing 2015
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