A 3D simulation analysis of reactive flow in screw elements of closely intermeshing twin screw extruders / Ederley Ortiz-Rodriguez in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 4 (08/2012)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVII, N° 4 (08/2012) . - p. 442-451 Titre : A 3D simulation analysis of reactive flow in screw elements of closely intermeshing twin screw extruders : Scale-up calculations Type de document : texte imprimé Auteurs : Ederley Ortiz-Rodriguez, Auteur ; C. Tzoganakis, Auteur Année de publication : 2012 Article en page(s) : p. 442-451 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Ecoulement permanent Extrudeuse bi-vis Modélisation tridimensionnelle Peroxydes Polypropylène Rhéologie Simulation par ordinateur Index. décimale : 668.9 Polymères Résumé : The peroxide-initiated degradation of polypropylene in conventional screw elements of closely intermeshing twin-screw extruders is analyzed by means of a three-dimensional (3D) simulation approach. The 3D simulations of the reacting flow are implemented under the assumption of steady-state flow conditions, and scale-up considerations are addressed by simulating screw elements of two different size extruders. The effects of the initial peroxide concentration and reference mass throughputs on processing parameters are analyzed in terms of the specified extruder size. In this study, the scaled-up mass throughput is determined under the assumption of constant residence time. For the implemented processing conditions, the final values of the weigh-average molecular weight (Mw) and polidispersity index (PDI) for both the reference and scaled-up screw elements are similar when the flow rate is close to that corresponding to the maximum conveying capacity of the screw elements. For more restricted flow conditions, however, lower values of both the Mw and PDI are obtained for the larger screw element. Additionally, a previously proposed scale-up procedure from one-dimensional (1D) simulations is evaluated by means of a 3D simulation analysis. The results of this evaluation show a good agreement between the trend of the 3D and 1D simulation results. Note de contenu : - Modeling considerations - Set up of the simulations and processing conditions - Discussion and results : Genral scale-up calculation analysis - Thermal time analysis DOI : 10.3139/217.2568 En ligne : https://drive.google.com/file/d/1X1cNmVTFhJmSjh-difgAne0WIojvpuB0/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15767 [article]

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Devulcanization of scrap tire rubber with supercritical CO2 : A study of the effects of process parameters on the properties of devulcanized rubber / M. Meysami in INTERNATIONAL POLYMER PROCESSING, Vol. XXXII, N° 2 (05/2017)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXII, N° 2 (05/2017) . - p. 183–193 Titre : Devulcanization of scrap tire rubber with supercritical CO2 : A study of the effects of process parameters on the properties of devulcanized rubber Type de document : texte imprimé Auteurs : M. Meysami, Auteur ; C. Tzoganakis, Auteur ; P. Mutyala, Auteur ; S. H. Zhu, Auteur ; M. Bulsari, Auteur Année de publication : 2017 Article en page(s) : p. 183–193 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caoutchouc -- Propriétés mécaniques Dévulcanisation Elastomères -- Extrusion Fluides supercritiques Rhéologie Index. décimale : 668.4 Plastiques, vinyles Résumé : A continuous extrusion devulcanization process has been developed by using supercritical CO2. Experiments have been carried out on an industrial scale twin screw extruder to study the effects of processing conditions on the properties of devulcanized rubber. Using a fractional factorial design in three levels, the effects of process temperature, screw speed, and feed rate on the sol fraction, degree of devulcanization, Mooney viscosity, and tensile properties of devulcanized rubber have been investigated. The significance of the effects of the processing conditions decreases in the following order: flow rate, screw speed, and process temperature. Similar trends are noted for different responses with the exception of tensile properties. The observed relationship between the sol fraction and the degree of crosslinking in the rubber samples before and after devulcanization points to a highly selective disruption of the sulfur crosslinks in the rubber network during devulcanization rather than a random network scission. Mooney viscosity has been found to be in excellent agreement with the network structure properties, sol fraction, and degree of devulcanization. Note de contenu : - EXPERIMENTAL : Materials and equipment - Experimental design - Characterization techniques - RESULTS AND DISCUSSION : Network analysis - Mooney viscosity and curing characteristics - Tensile properties DOI : 10.3139/217.3290 En ligne : https://drive.google.com/file/d/1PxINeCjfqgt2gDJMtBm0w9pHzAt4h37a/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=28497 [article]

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Functionalization of PP with sulfonyl azide through reactive processing / Q. Li in INTERNATIONAL POLYMER PROCESSING, Vol. XXII, N° 3 (07/2007)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXII, N° 3 (07/2007) . - p. 311-319 Titre : Functionalization of PP with sulfonyl azide through reactive processing Type de document : texte imprimé Auteurs : Q. Li, Auteur ; C. Tzoganakis, Auteur Année de publication : 2007 Article en page(s) : p. 311-319 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The functionalization of polypropylene (PP) by 4-carboxybenzene sulfonyl azide (CBSA) was investigated in a batch mixer and the reaction was monitored through FTIR, 1H-NMR and XPS spectroscopy. The degree of grafting was found to increase initially with azide feed content and subsequently to level off at azide concentrations of 2wt.%. Experiments performed at different reaction temperatures showed that a maximum degree of grafting was obtained around 190°C. The linear viscoelastic properties the functionalized PPs were also evaluated by oscillatory shear measurements and were found to correlate with the grafting degree results. Finally, the adhesive properties of the functionalized PPs were evaluated through peel tests on aluminum substrates. The peel strength increased with the degree of grafting and it was found to be significantly higher for purified samples than for non-purified ones. Finally, it was demonstrated that the cooling rate of the PP/aluminum laminate specimens had a major effect on the peel strength. DOI : 10.3139/217.2039 En ligne : https://drive.google.com/file/d/1gDbOP0VM1LvXvXjpMetPzqOvvjS_q7LU/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2709 [article]

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Numerical simulation of polymer coextrusion flows / M. Zatloukal in INTERNATIONAL POLYMER PROCESSING, Vol. XVI, N° 2 (06/2001)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVI, N° 2 (06/2001) . - p. 198-207 Titre : Numerical simulation of polymer coextrusion flows : A criterion for detection of "wave" " interfacial instability onset Type de document : texte imprimé Auteurs : M. Zatloukal, Auteur ; C. Tzoganakis, Auteur ; J. Vlcek, Auteur ; P. Saha, Auteur Année de publication : 2001 Article en page(s) : p. 198-207 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Non-isothermal calculation of flow history dependent viscoelastic stresses in a coextrusion die is performed using the 8-mode modified Leonov constitutive equation and the deformation rate field from finite element simulation. It is shown that a heuristic criterion based on the difference of normal stress differences across the layer interfaces in the merging area may be used to potentially detect the onset of interfacial instabilities. The developed technique can be a useful tool for coextrusion die design as well as for proper selection of materials and process conditions for coextrusion. DOI : 10.3139/217.1642 En ligne : https://drive.google.com/file/d/1UN4e12VUmFm7vhvvbZiX2PeBCieYN8zj/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15900 [article]

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Rheological indicators for environmental stress cracking resistance of polyethylene / P. Sardashti in INTERNATIONAL POLYMER PROCESSING, Vol. XXX, N° 1 (03/2015)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXX, N° 1 (03/2015) . - p. 70-81 Titre : Rheological indicators for environmental stress cracking resistance of polyethylene Type de document : texte imprimé Auteurs : P. Sardashti, Auteur ; C. Tzoganakis, Auteur ; M. Zatloukal, Auteur ; M. A. Polak, Auteur ; A. Penlidis, Auteur Année de publication : 2015 Article en page(s) : p. 70-81 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation Cisaillement (mécanique) Contraintes (mécanique) Essais dynamiques Matières plastiques -- Fissuration Polyéthylène basse densité linéaire Polymères -- Détérioration Rhéologie Traction (mécanique) Index. décimale : 668.9 Polymères Résumé : Most studies on environmental stress cracking resistance (ESCR) of polymers have focused on performing mechanical tests in the solid state. In this work, investigations in the melt state were carried out, to identify potential melt indicators for a relative measure of ESCR. A normalized characteristic relaxation time (?N), obtained from dynamic shear experiments, was established as a valid measure of ESCR of linear low density polyethylene, where a large content of short chain branches is present. In addition, the melt strain hardening coefficient (MSHC), obtained from extensional rheological methodologies, was found to be another potential and reliable indicator of ESCR. An inverse correlation between MSHC and ESCR was observed, indicating an inverse relationship between ESCR and chain extensibility in the melt. Furthermore, a new factor called “melt hardening stiffness (mHS)” was developed from the slope of a stress vs. Hencky strain obtained from a Sentmanat extensional rheometer. mHS was found to be another promising indicator of ESCR obtained from rheological studies conducted in this work. Note de contenu : - EXPERIMENTAL : Materials - Molecular characterization - Tensile strain hardening (HS) test - Rheological characterization - RESULTS AND DISCUSSION : Rheological characteristics under shear - Rheological characteristics under extension DOI : 10.3139/217.2963 En ligne : https://drive.google.com/file/d/1cIjs2AX60nJx7DNBTIElUBe27-FBmf68/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23424 [article]

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Rheological modification of LLDPE through reactive processing with peroxide / P. Tasanatanachai in INTERNATIONAL POLYMER PROCESSING, Vol. XXIII, N° 2 (05/2008)  

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Scaling-up a reactive extrusion operation : A one-dimensional simulation analysis / Ederley Ortiz-Rodriguez in INTERNATIONAL POLYMER PROCESSING, Vol. XXV, N° 3 (07/2010)  

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