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Ajouter le résultat dans votre panier Affiner la rechercheIn-process rheometry studies of LDPE compounds / A. L. Kelly in INTERNATIONAL POLYMER PROCESSING, Vol. XV, N° 4 (12/2000)
Titre : In-process rheometry studies of LDPE compounds : Part I : Unfilled resin Type de document : texte imprimé Auteurs : A. L. Kelly, Auteur ; M. Woodhead, Auteur ; D. Barnwell, Auteur ; K. Martin, Auteur ; P. D. Coates, Auteur Année de publication : 2000 Article en page(s) : p. 355-360 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The initial part of a comprehensive study into the investigation and validation of in-process measurements on a low density polyethylene (LDPE) compound during extrusion is reported. An unfilled, commercial grade of low density polyethylene was processed using fully instrumented, computer monitored, single and twin screw extruders in the Interdisciplinary Research Centre (IRC) laboratories, University of Bradford. Three in-process rheometers were used; a prototype Rosand capillary on-line rheometer (OLR), a four sensor slit die in-line rheometer (ILR) and a six sensor slit die ILR. Off-line comparisons were carried out using a Rosand RH7 twin bore capillary rheometer. All devices allowed shear flow characterisation at a range of processing rates, and the capillary rheometers also provided a measurement of entry pressure drop through the use of orifice dies. The six-sensor ILR also allowed measurement of entry pressure drop into the slit, although the differences in flow geometry meant these measurements were not directly comparable with the capillary devices, and exit pressures were extrapolated from ILR pressure drops. The in-process devices exhibited very good agreement with measurements made off-line, in both shear flow and entry pressures. In-line slit die measurements were very close to those made using capillary dies, despite the in-line tests being non-isothermal and employing a different geometry of measurement section. Differences in melt rheology between single and twin extrusion were observed, due to the amount of mechanical work input by each extruder. Overall, good agreement was observed from the four different routes to measurement, for the LDPE examined. DOI : 10.3139/217.1612 En ligne : https://drive.google.com/file/d/1_iQvHCt9XuClrlRnNyA6lbtfAdKCTCbF/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16146
in INTERNATIONAL POLYMER PROCESSING > Vol. XV, N° 4 (12/2000) . - p. 355-360[article]Réservation
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Titre : In-process rheometry studies of LDPE compounds : Part II : Magnesium hydroxide filled Type de document : texte imprimé Auteurs : A. L. Kelly, Auteur ; M. Woodhead, Auteur ; P. D. Coates, Auteur ; D. Barnwell, Auteur ; K. Martin, Auteur Année de publication : 2000 Article en page(s) : p. 361-368 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Screw extrusion/Mixing - The second part of a comprehensive study into the investigation and validation of in-process measurements on a low density polyethylene compound during extrusion is reported. A commercial grade of branched low density polyethylene was used in the study, compounded with various levels of magnesium hydroxide flame retardant filler, up to 50% by weight. In-line and on-line rheometry were used to monitor melt flow behaviour during single screw and twin screw extrusion; off-line capillary rheometry was performed on the compound before and after extrusion, to examine any change in rheology. Morphological observations were made using scanning electron microscopy, and molecular characterisations carried out using gel permeation chromatography. In-process rheometry was found to be able to detect the presence of filler at low and high loadings, but was unable to discriminate between intermediate levels. Off-line rheometry indicated that twin screw extrusion altered the rheology of the compound, and capillary wall slip was found to increase after extrusion. Morphological observation indicated that filler in the compound was better dispersed after extrusion, especially at high volume fractions. Molecular weight and polydispersity of the LDPE were shown to increase after extrusion, more so in the case of low filler loadings. Overall, in-process measurements provided useful rheological data, and the compound was found to exhibit complex, process-dependent rheology. DOI : 10.3139/217.1613 En ligne : https://drive.google.com/file/d/1Mw1gsaUXcM_GqpMC90x-25j8e0Zrht8o/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16154
in INTERNATIONAL POLYMER PROCESSING > Vol. XV, N° 4 (12/2000) . - p. 361-368[article]Réservation
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