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In situ observation of nucleated polymer crystallization in polyoxymethylene sandwich composites
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SYSNO ASEP 0444199 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title In situ observation of nucleated polymer crystallization in polyoxymethylene sandwich composites Author(s) Šlouf, Miroslav (UMCH-V) RID, ORCID
Krejčíková, Sabina (UMCH-V)
Vacková, Taťana (UMCH-V) RID
Kratochvíl, Jaroslav (UMCH-V) RID
Novák, L. (CZ)Source Title Frontiers in Materials. - : Frontiers Media - ISSN 2296-8016
Roč. 2, 19 March (2015), 23_1-23_12Number of pages 12 s. Language eng - English Country CH - Switzerland Keywords polyoxymethylene ; nucleated crystallization ; sandwich composites Subject RIV JJ - Other Materials R&D Projects GAP205/10/0348 GA ČR - Czech Science Foundation (CSF) GA14-17921S GA ČR - Czech Science Foundation (CSF) TE01020118 GA TA ČR - Technology Agency of the Czech Republic (TA ČR) Institutional support UMCH-V - RVO:61389013 UT WOS 000218498500028 EID SCOPUS 85009711432 DOI 10.3389/fmats.2015.00023 Annotation We introduce a dynamic sandwich method, which can be used for in situ observation and quantification of polymer crystallization nucleated by micro/nanoparticles. The method was applied on polyoxymethylene (POM) composites with three nucleating agents: talc micropowder (POM/mTalc), chalk nanopowder (POM/nChalk), and titanate nanotubes (POM/TiNT). The nucleating agents were deposited between polymer films, the resulting sandwich samples were consolidated by thermal treatment, and their microtomed cross-sections were observed during isothermal crystallization by polarized light microscopy (PLM). As the intensity of polarized light was shown to be proportional to the relative crystallinity, the PLM results could be fitted to Avrami equation and the nucleating activity of all investigated particles could be quantified by means of Avrami parameters (n, k). The crystallization half-times increased reproducibly in the following order: POM/nChalk < POM/mTalc < POM/TiNT ~ POM. For strong nucleating agents (mTalc, nChalk), the crystallization kinetics corresponded to spontaneous crystallization starting from central nucleating layer, which was verified by computer simulations. The results were also confirmed by differential scanning calorimetry. We concluded that the sandwich method is an efficient microscopic technique for detailed evaluation of nucleating activity of arbitrary micro/nanoparticles in polymer systems. Workplace Institute of Macromolecular Chemistry Contact Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358 Year of Publishing 2016
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