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Injection-moulded alpha- and beta-polypropylenes: I. Structure vs. processing parameters

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dc.title Injection-moulded alpha- and beta-polypropylenes: I. Structure vs. processing parameters en
dc.contributor.author Čermák, Roman
dc.contributor.author Obadal, Martin
dc.contributor.author Ponížil, Petr
dc.contributor.author Polášková, Martina
dc.contributor.author Stoklasa, Karel
dc.contributor.author Lengálová, Anežka
dc.relation.ispartof European Polymer Journal
dc.identifier.issn 0014-3057 Scopus Sources, Sherpa/RoMEO, JCR
dc.date.issued 2005-08
utb.relation.volume 41
utb.relation.issue 8
dc.citation.spage 1838
dc.citation.epage 1845
dc.type article
dc.language.iso en
dc.publisher Pergamon Elsevier Science Ltd. en
dc.identifier.doi 10.1016/j.eurpolymj.2005.02.020
dc.relation.uri https://www.sciencedirect.com/science/article/pii/S0014305705000844
dc.subject polypropylene en
dc.subject skin-core morphology en
dc.subject alpha-form en
dc.subject beta-form en
dc.subject specific nucleation en
dc.subject processing parameters en
dc.description.abstract The paper studies the effects of mould temperature and holding pressure on the structure of neat and beta-nucleated isotactic polypropylenes. Commercially available isotactic polypropylene was modified with a beta-specific nucleator based on N,N'-dicyclohexylnaphthalene-2,6-dicarboxamide in the concentration of 0.03 wt.%. From both the original material (alpha-iPP) and the beta-nucleated material (beta-iPP), dog bone-shaped test specimens were injection-moulded, using two sets of processing parameters. In the T-set the mould temperature was varied within the range of 40-120 degrees C in 10 degrees C steps, while in the beta-set the holding pressure was changed from 5 to 13 MPa in 1 MPa steps. Other processing parameters were kept on the same level. Polarized-light microscopy showed a strong effect of mould temperature on the morphology of alpha-iPP specimens; the skin thinned out and the spherulite size increased with mould temperature rise. On the other hand, in the case of alpha-iPP only the skin thickness was correspondingly affected, while the spherulite size remained virtually constant, independent of the mould temperature changes. At the same structure level, both alpha-iPP and beta-iPP specimens were insensitive to holding pressure variations. Polymorphic composition derived from wide-angle X-ray scattering displayed similar range of changes induced by variations of the processing parameters for both materials. The increase of mould temperature positively influenced the crystallinity and the P-form content, particularly in the skin of specimens. On the contrary, higher holding pressure depressed the crystallinity proportionally within the bulk of specimens. (c) 2005 Elsevier Ltd. All rights reserved. en
utb.faculty Faculty of Technology
dc.identifier.uri http://hdl.handle.net/10563/1002060
utb.identifier.scopus 2-s2.0-20344403292
utb.identifier.wok 000230638600017
utb.identifier.coden EUPJA
utb.source j-wok
dc.date.accessioned 2011-08-16T15:06:19Z
dc.date.available 2011-08-16T15:06:19Z
utb.contributor.internalauthor Čermák, Roman
utb.contributor.internalauthor Obadal, Martin
utb.contributor.internalauthor Ponížil, Petr
utb.contributor.internalauthor Polášková, Martina
utb.contributor.internalauthor Stoklasa, Karel
utb.contributor.internalauthor Lengálová, Anežka
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