Extensional rheology and processing of polymeric materials / H. Münstedt in INTERNATIONAL POLYMER PROCESSING, Vol. XXXIII, N° 5 (11/2018)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXIII, N° 5 (11/2018) . - p. 594-618 Titre : Extensional rheology and processing of polymeric materials Type de document : texte imprimé Auteurs : H. Münstedt, Auteur Année de publication : 2018 Article en page(s) : p. 594-618 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Déformations (mécanique) Ecrouissage Filature Films plastiques Matières plastiques -- Soufflage Matières plastiques -- Thermoformage Moussants Rhéologie Index. décimale : 668.4 Plastiques, vinyles Résumé : Many processing operations of polymeric materials are dominated by extensional flow. In this paper the question is addressed in which way rheological data obtained from elongational laboratory experiments can be used to describe the material behavior in various processes. Particularly discussed is the uniformity of geometrical features of items with respect to the strain hardening of the polymeric materials, because uniformity is important for many end-use properties. Convincing correlations with extensional rheology could not be established for thermoforming experiments on polypropylene. However, for blown and drawn films it was found that the uniformity of thickness improved, if strain hardening was introduced. The bubble stability could be related to the melt strength of the sample. Furthermore, the influences of elasticity and strain hardening on the neck-in during drawing of films were elucidated. Moreover, it was shown in which way extensional rheology can be used to assess foaming. Note de contenu : - Main features of rheological properties in elongation - Relevance of strain hardening for the uniformity of stretched samples - Experimental methods - Biaxial deformations - Fiber spinning - Thermoforming - Film blowing - Film casting - Foaming DOI : 10.3139/217.3532 En ligne : https://www.degruyter.com/document/doi/10.3139/217.3532/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31391 [article]

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Polymer processing extrusion instabilities and methods for their elimination or minimisation / Jean-François Agassant in INTERNATIONAL POLYMER PROCESSING, Vol. XXI, N° 3 (07/2006)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXI, N° 3 (07/2006) . - p. 239-255 Titre : Polymer processing extrusion instabilities and methods for their elimination or minimisation Type de document : texte imprimé Auteurs : Jean-François Agassant, Auteur ; Bruno Vergnes, Auteur ; L. Robert, Auteur ; M. R. Mackley, Auteur ; H. Münstedt, Auteur ; A. Merten, Auteur ; C. Combeaud, Auteur ; D. R. Arda, Auteur Année de publication : 2006 Article en page(s) : p. 239-255 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : This paper presents and reviews findings in relation to three key areas where polymer processing instabilities occur. The paper also describes methods that can be utilised to reduce, or eliminate, the particular instability. Using previously published results in each of the three areas and work presented in the paper, physical insight into the three mechanisms is reviewed and compared. Extrusion instabilities develop with increasing extrusion rate and the onset of extrusion instability is often a key limitation to the maximum output of an extrusion line. The sharkskin instability is an exit effect instability that can be modified by changing exit geometries and eliminated using certain additives. The stick-spurt instability is intimately related to wall boundary conditions which can be influenced by certain wall and polymer formulations. Finally volume instabilities occur in the entry region of a die and result in a highly distorted product. The instabilities are related to viscoelastic effects within the die and can be minimised by appropriate die and polymer modification. The paper provides sufficient experimental background to identify the key physical aspects associated with each of the instabilities and this in turn provides insight into the different way each instability occurs and how they can be minimised. DOI : 10.3139/217.0084 En ligne : https://drive.google.com/file/d/10hHIv-ZkJl2JxKlmSkVKcF1XyjhKA-tT/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2838 [article]

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Selectively metallisable polymer compounds / Susanne Michler in KUNSTSTOFFE PLAST EUROPE, Vol. 95, N° 12/2005 (12/2005)

[article]  inKUNSTSTOFFE PLAST EUROPE > Vol. 95, N° 12/2005 (12/2005) . - p. 52-56 Titre : Selectively metallisable polymer compounds Type de document : texte imprimé Auteurs : Susanne Michler, Auteur ; Jürgen Kanzler, Auteur ; H. Münstedt, Auteur Année de publication : 2005 Article en page(s) : p. 52-56 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.4 Plastiques, vinyles Résumé : Plug-in connectors - Compounds - In the field of injection-moulded interconnect devices, the demand for polymer compounds with the property of selective metallisation is increasing all the time. What is wanted are material combinations with differing metallisation behaviour. This essentially means that, using an electroless metallisation process, metal is deposited with good adhesion on one plastic component but not on the other. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=7310 [article]

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Simultaneous biaxial stretching of polypropylene resins of varying tacticity / L. Capt in INTERNATIONAL POLYMER PROCESSING, Vol. XX, N° 4 (12/2005)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 4 (12/2005) . - p. 369-379 Titre : Simultaneous biaxial stretching of polypropylene resins of varying tacticity : Part II : Film morphology and properties Type de document : texte imprimé Auteurs : L. Capt, Auteur ; S. Rettenberger, Auteur ; H. Münstedt, Auteur ; Musa R. Kamal, Auteur Année de publication : 2005 Article en page(s) : p. 369-379 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The simultaneous biaxial stretching behavior of three Ziegler-Natta-based isotactic polypropylene resins of varying isotacticity was studied using a laboratory film stretcher that simulates closely stretching conditions encountered in the commercial process. The effect of isotacticity on the final morphology and end film properties was associated with the effect of isotacticity on the thermal properties of the resin. The results showed that the degree of undermelting, (delta) Tum = Tm–T, determines the phase composition of the polymer before stretching and the morphology and orientation of the stretched films. The size and orientation of the crystallites in the stretching plane is mostly determined by the degree of undermelting. The elongation at break was correlated with the residual crystallinity of the film before stretching, and the elastic modulus was correlated with the final degree of crystallinity and the density of tie chains. En ligne : https://drive.google.com/file/d/1tgOrSORI2P-gqkg5hc4mXcpKqBvAhkXa/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2962 [article]

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Simultaneous biaxial stretching of PP resins of varying / L. Capt in INTERNATIONAL POLYMER PROCESSING, Vol. XX, N° 1 (03/2005)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 1 (03/2005) . - p. 35-46 Titre : Simultaneous biaxial stretching of PP resins of varying : Tacticity melting and deformation behavior Type de document : texte imprimé Auteurs : L. Capt, Auteur ; S. Rettenberger, Auteur ; H. Münstedt, Auteur ; Musa R. Kamal, Auteur Année de publication : 2005 Article en page(s) : p. 35-46 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The melting and simultaneous biaxial stretching behavior of three Ziegler-Natta isotactic polypropylene resins of varying isotacticity was studied. DSC melting experiments showed that the crystallinity and melt stability of the crystalline phase depend strongly on tacticity and on the degree of undermelting, Delta T = Tm–T, where Tm is the melting temperature. The level of biaxial yield stress depends on the fraction of residual "unmolten" crystallinity and the crystallite size. For specimens with same thermal history, the post-yield deformation shows strong dependence on the degree of undermelting, delta T. The deformation homogeneity and the resulting film thickness may be related to the thermal mobility of the chains and the tie chain and entanglement densities. DOI : 10.3139/217.1867 En ligne : https://drive.google.com/file/d/1DSnN2JaRS7LdBD_xx8Ox7uBm2a7BMBa6/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3088 [article]

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Using supercritical carbon dioxide for ohysical foaming of advanced polymer materials / F. Wolff in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 4 (09/2011)  

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