Improved spinnability of metallocene polyethylenes by using processing aids / R. Vogel in INTERNATIONAL POLYMER PROCESSING, Vol. XVIII, N° 1 (03/2003)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 1 (03/2003) . - p. 67-73 Titre : Improved spinnability of metallocene polyethylenes by using processing aids Type de document : texte imprimé Auteurs : R. Vogel, Auteur ; Savvas G. Hatzikiriakos, Auteur ; Harald Brünig, Auteur ; B. Tändler, Auteur ; M. Golzar, Auteur Année de publication : 2003 Article en page(s) : p. 67-73 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Melt spinning is a polymer processing technique that is strongly influenced by the extensional flow behaviour of polymer melts. Therefore only a few polymeric materials are usable for this kind of processing with sufficient take-up speeds. When approaching critical conditions of deformation most polymers show either fibre break in the molten state either by a brittle cohesive rupture or a ductile failure. During the melt spinning of pure and modified metallocene poylethylenes additional flow instabilities occur within the spinning die. Namely, wall slip, 'sharkskin' and pressure oscillations (gross fracture) may be obtained dependending on the volume flow rate. Pressure oscillations lead to diameter oscillations of the melt extrudate, which create local increase of tensile stress in the spin line. This effect immediately causes fiber break in the spinline. Therefore, melt spinning of polyethylenes was only possible up to a critical molecular weight or its relating melt viscosity. The limitation of the molecular weight restricts the mechanical properties of the melt spun fibres. This paper reports on an attempt to find out appropriate processing aids for suppressing 'sharkskin' effects and pressure oscillations in an attempt to overcome the limitation of a critical molecular weight. At first, the critical conditions for the onset of flow instabilities for higher molecular weight polymers were analysed. Further experiments concerned with the use of processing aids for melt spinning of metallocene polyethylenes of higher molecular weights. A combination of boron nitride powder and a fluoroelastomer was found to be an effective processing aid for this process. DOI : 10.3139/217.1722 En ligne : https://drive.google.com/file/d/1QKKoX0SBuwLGtIqeg0yo6MePu06Ntr77/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15851 [article]

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Melt spinning of reactive extruded and/or blended polymer fibers by means of an online coupled twin screw extruder / R. Beyreuther in INTERNATIONAL POLYMER PROCESSING, Vol. XVIII, N° 1 (03/2003)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 1 (03/2003) . - p. 74-79 Titre : Melt spinning of reactive extruded and/or blended polymer fibers by means of an online coupled twin screw extruder Type de document : texte imprimé Auteurs : R. Beyreuther, Auteur ; B. Tändler, Auteur ; R. Vogel, Auteur ; M. Hoffmann, Auteur Année de publication : 2003 Article en page(s) : p. 74-79 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : After some general introductory remarks to the advantageous application of a twin screw extrusion to the melt spinning the lecture deals with investigations of elastomeric fibers consisting of ethylene-octene-copolymers which have been grafted by organosilanes and additionally blended with polybutylenterephthalates (PBT) and/or polyesterelastomers (PEE), all by means of a reactive twin screw extruder coupled with a side feeding single screw extruder in an online melt spinning process. It will be demonstrated that considerably improved mechanical properties of the elastomeric EO-fibers can be reached with this additional blend step. All spun fiber samples will be characterized regarding their structural and mechanical properties extensively. This work is a decisive expansion of our results published during the last two years regarding to the twin screw extrusion melt spinning [1 to 4]. DOI : 10.3139/217.1724 En ligne : https://drive.google.com/file/d/1YnVPOkI0SChNOG7SPdfcTMJL9WmP2r1J/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15852 [article]

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Preferable filament diameter ratios of hybrid yarn components for optimized longfiber reinforced thermoplastics / R. Beyreuther in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVII, N° 2 (06/2002) . - p. 153-157 Titre : Preferable filament diameter ratios of hybrid yarn components for optimized longfiber reinforced thermoplastics Type de document : texte imprimé Auteurs : R. Beyreuther, Auteur ; Harald Brünig, Auteur ; R. Vogel, Auteur Année de publication : 2002 Article en page(s) : p. 153-157 Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The mechanical properties of hybrid (commingled) yarn based reinforced thermoplastics depend on many parameters of the fiber components as well as of the different technological conditions during the commingling and the hot press molding. Among the fiber parameters the diameter ratio of the matrix and the reinforcing yarn components are most important to obtain the best mechanical properties of the reinforced thermoplastics. The paper treats theoretical considerations in order to reach a high probability of coating each reinforcing filament with the thermoplastic material during the hot press molding. The calculations include the filament ratios and the achieved volume ratios of both hybrid yarn components of the finished reinforced thermoplastics. It is demonstrated the under different optimization criterias (same filament numbers for both components or the same surfaces of the reinforcing yarn filaments and the matrix yarn filaments before the hot press molding) a more or less small range of filament ratios seem to be valid for manufacturing a homogeneous faultless reinforced thermoplastic. Quantitative calculations for two hybrid yarn systems PEEK/carbon fibers and PP/glass fibers, presented in diagrams, are demonstrated. Technological conditions for the spinning of micro fibers like PEEK-filaments complete the presentation. Note de contenu : - Theoretical investigations concerning the diameter ratios - Melt spinning of microfiber like filaments DOI : 10.3139/217.1681 En ligne : https://drive.google.com/file/d/1oJ5tJPe_RPFD7bm5BN7eeig3Rhdh8Xio/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15944 [article]

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Rheological and theoretical estimation of the spinnability of polyolefines / R. Vogel in INTERNATIONAL POLYMER PROCESSING, Vol. XIV, N° 1 (03/1999)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XIV, N° 1 (03/1999) . - p. 69-74 Titre : Rheological and theoretical estimation of the spinnability of polyolefines : Part I : Rheological study Type de document : texte imprimé Auteurs : R. Vogel, Auteur ; Harald Brünig, Auteur ; R. Beyreuther, Auteur ; B. Tändler, Auteur ; D. Voigt, Auteur Année de publication : 1999 Article en page(s) : p. 69-74 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Fibers and films - Melt spinning is a polymer processing technique that makes great demands on the extensibility of the polymer melt in the distance between die exit and solidification point [1]. The polymer material is exposed to a rapidly growing deformation rate over a large range of deformation within a short time of about 100 milliseconds. Simultaneously an extreme cooling occurs with cooling rates of about 1000 K/s. For this reason only a few polymer materials are usable for this kind of polymer processing with sufficient take-up speeds. Most polymers show afiber break in the motten state either by brittle cohesive rupture or ductile failure when approaching critical conditions of deformation. The rheological behaviour of a polymer melt at the critical conditions of deformation in the fiber forming process can not be predicted by means of usual rheological material functions. This paper reports the attempt to find out material functions, which describe the critical deformation states of the melt spinning process. The established material functions are compared with the results of spinning experiments to estimate their practicality. DOI : 10.3139/217.1518 En ligne : https://drive.google.com/file/d/1NHp5HYl1M0Ym8rPxPuT4r80dARmOnGr-/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16114 [article]

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