High shear processing of (PP/EPR)/silica nanocomposites : improvement of morphology and properties / M. Louizi in INTERNATIONAL POLYMER PROCESSING, Vol. XXIX, N° 1 (03/2014)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXIX, N° 1 (03/2014) . - p. 118-127 Titre : High shear processing of (PP/EPR)/silica nanocomposites : improvement of morphology and properties Type de document : texte imprimé Auteurs : M. Louizi, Auteur ; Valérie Massardier, Auteur ; F. Melis, Auteur ; P. Alcouffe, Auteur ; Philippe Cassagnau, Auteur Année de publication : 2014 Article en page(s) : p. 118-127 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Allongement à la rupture Caoutchouc Cisaillement (mécanique) Composites -- Propriétés mécaniques Copolymère éthylène propylène Elastomères Morphologie (matériaux) Nanoparticules Polypropylène Résistance au chocs Rhéologie Résumé : The aim of this article is to upgrade the performance of polypropylene/ethylene propylene rubber (PP/EPR) blends by addition of hydrophobic nanosilica (SiR805) and using "high shear processing technology". The morphological developments, mechanical and rheological properties of these composites were investigated as a function of processing conditions. High shear processing has proved to be an efficient process to decrease the size of the dispersed phase (EPR) up to 300 nm and to disperse finely nanosilica particles to less than 30 nm especially at 800 min?1. Moreover, the morphology stability of the nanocomposite is ascribed to the formation of a core shell structure (EPR nodules = core; nano-silica = shell) and selective location of nanosilica at the interface. More importantly, this core-shell structure is favoured to enhance the impact strength of the (PP/EPR)/3 wt% SiR805 nanocomposite. In agreement to the obtained morphology, the improvement (about 60 %) of elongation at break attests a good adhesion between phases due to high shear effect as highlighted by viscoelastic properties. Therefore, high shear processing technology has proved to be a relevant method to prepare nanocomposites with high performances without adding any additive and offers new perspectives for recycling and lightening structures. Note de contenu : - Materials - Nanocomposites preparation - Morphology characterization - Rheological analysis - Mechanical properties DOI : 10.3139/217.2819 En ligne : https://drive.google.com/file/d/1-WiX6aZP71Yks8UZWiPU5gZihEK2IjsT/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=20583 [article]

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Organic-inorganic hybrid material synthesis by on line coupling twin screw extruder with a microwave oven / S. Jiguet in INTERNATIONAL POLYMER PROCESSING, Vol. XX, N° 4 (12/2005)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 4 (12/2005) . - p. 345-351 Titre : Organic-inorganic hybrid material synthesis by on line coupling twin screw extruder with a microwave oven Type de document : texte imprimé Auteurs : S. Jiguet, Auteur ; A. Michel, Auteur ; F. Melis, Auteur ; Véronique Bounor-Legaré, Auteur Année de publication : 2005 Article en page(s) : p. 345-351 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : A new process for elaborating continuously organic-inorganic hybrid materials by reactive extrusion is presented. This synthesis consists in formulating a copolymer of ethylene and vinyl acetate (EVA)/tetrapropoxysilane (TPOS or Si(OC3H7)4)/catalyst blend by a corotating twin screw extruder followed by two successive reaction steps: on line microwave crosslinking reaction and hydrolysis-condensation reactions leading to a silica network cografted onto the organic matrix. Extrusion feed rate (Q), temperature, microwave oven power (P), and microwave curing time (tmw) were studied. Crosslinking density was evaluated before and after hydrolysis-condensation reactions and compared with the previous results obtained in static conditions. These materials tailored by an on line process present a permanent elasticity at high temperature (up to 200 °C) and a certain optical transparency. This new approach offers the possibility to synthesize massive samples based on organic-inorganic hybrid material. DOI : 10.3139/217.2003 En ligne : https://drive.google.com/file/d/1WcFViNV5bIg2_qPKR-iKC_BgJ-zClrsP/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2959 [article]

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Residence time distribution in a high shear twin screw extruder / E. Fel in INTERNATIONAL POLYMER PROCESSING, Vol. XXIX, N° 1 (03/2014)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXIX, N° 1 (03/2014) . - p. 71-80 Titre : Residence time distribution in a high shear twin screw extruder Type de document : texte imprimé Auteurs : E. Fel, Auteur ; Valérie Massardier, Auteur ; F. Melis, Auteur ; Bruno Vergnes, Auteur Année de publication : 2014 Article en page(s) : p. 71-80 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cisaillement (mécanique) Distribution de temps de séjour Extrudeuse bi-vis Polypropylène Simulation par ordinateur Index. décimale : 668.4 Plastiques, vinyles Résumé : The residence time distributions (RTD) of a high shear twin screw extruder were measured by an on–line UV fluorescence device. First, by increasing throughput (Q) and screw speed (N), a decrease of the complex viscosity of the studied polypropylene (PP) was observed, revealing chain scissions. It was associated to high viscous dissipation taking place during extrusion, and more particularly under high shear conditions. Then the impact of these experimental conditions on the RTD was carried out. As expected, an increase of usual throughputs and screw speeds decrease mostly the RTD characteristic data. In this study industrial rate have been studied: throughput varied from 1.5 up to 22 kg h?1 and screw speed varied from 200 min?1 up to 1 200 min?1. However, by increasing the screw speed over usual values (from 500 up to 1 200 min?1), the variation of some experimental RTD characteristics were unexpected. Indeed, the slope of the shape of the experimental RTD function E(t) changed significantly. This phenomenon will be called lag or delay time. This result was only observed at low throughputs and high screw rotation speeds. To finish, a modeling software of twin screw extrusion process was used to compare experimental and calculated results. For usual processing conditions (up to 700 min?1), the simulation predicts nicely the experimental RTDs. However, at high screw speed (N > 800 min?1) and moderate throughput (Q = 4 kg h?1), the simulation fails to predict the RDT delay time. Hence, some side effects apparently occurred during high shear extrusion at low throughputs. Note de contenu : - THEORETICAL ASPECTS : Residence time distribution (RTD) - MATERIALS AND METHODS : Material - Twin screw extruder - UV tracer and UV-fluorescence device - Bulk temperature - RESULTS AND DISCUSSION : Experimental results - Simulation from Ludovic software DOI : 10.3139/217.2805 En ligne : https://drive.google.com/file/d/1o_Iuqwuk5vId94nbqcSHDVbikBJ84ssh/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=20577 [article]

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