Accueil
Détail de l'auteur
Auteur H. Assempour |
Documents disponibles écrits par cet auteur
Ajouter le résultat dans votre panier Affiner la recherche
Determination of the residence time distribution in twin Screw extruders via free radical modification of PE / M. K. RazaviAghjeh in INTERNATIONAL POLYMER PROCESSING, Vol. XIX, N° 4 (12/2004)
[article]
Titre : Determination of the residence time distribution in twin Screw extruders via free radical modification of PE Type de document : texte imprimé Auteurs : M. K. RazaviAghjeh, Auteur ; Hossein Nazockdast, Auteur ; H. Assempour, Auteur Année de publication : 2004 Article en page(s) : p. 335-341 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The main objective of the present work was to introduce an inline method for measuring the residence time distribution (RTD) of twin screw extruders on the basis of information obtained from the melt free radical modification of polyethylene in a modular intermeshing co-rotating twin screw extruder. The trend of increasing rate of the extruder total torque resulted from replacing the neat polyethylene feed by a mixture of polyethylene and reactants which are chemically capable of creating chainbranching and/or crosslinking reactions was considered as the main information source for evaluating the RTD of the extruder. The RTD results were compared with those obtained from the tracer pulse input method, and good agreement was found. It was also demonstrated that, the present in-line RTD measuring technique has reliability of following the effect of feeding rate, screw speed and reactant concentration on the RTD of the twin screw extruders. It was found that, increasing the feeding rate results in decreasing the minimum residence time, and results in a narrower RTD. At constant feeding rate increasing the screw speed decreased the minimum residence time and broadened the RTD. The results also showed that, reactant concentration and variation of the viscosity along the screw have not appreciable effect on the twin screw extruders RTD. DOI : 10.3139/217.1842 En ligne : https://drive.google.com/file/d/1wrPVMP4aQXntatHiToIO_V1cSVa4BneJ/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3265
in INTERNATIONAL POLYMER PROCESSING > Vol. XIX, N° 4 (12/2004) . - p. 335-341[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001030 - Périodique Bibliothèque principale Documentaires Disponible Preparation and characterization of HMW PA 6 via anionic polymerization of E-caprolactam by using a mixture of di- and tri-functional chain initiators / M. M. S. Barmi in INTERNATIONAL POLYMER PROCESSING, Vol. XXI, N° 3 (07/2006)
[article]
Titre : Preparation and characterization of HMW PA 6 via anionic polymerization of E-caprolactam by using a mixture of di- and tri-functional chain initiators Type de document : texte imprimé Auteurs : M. M. S. Barmi, Auteur ; H. Assempour, Auteur ; Hossein Nazockdast, Auteur Année de publication : 2006 Article en page(s) : p. 230-238 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : In the present work, an attempt was made to synthesis polyamide 6 through anionic polymerization of e-Caprolactam by using a mixture of Diphenylmethan 4, 40-di and tri-isocyanate as a chain initiator and sodium caprolactamate as a catalyst. Polymerization was carried out in a laboratory internal mixer (Brabender). The rotor speed, reaction temperature and reaction time were among the processing variables studied. The prepared samples were characterized by Thermogravimetry Analysis (TGA), Differential Scanning Calorimeter (DSC) and FT-IR spectroscopy. The flow behavior and melt viscoelastic properties of the samples were studied by using a Rheometric Mechanical Spectrometer (RMS). The polymerization reaction was found to be very fast and was completed within 6 minutes. This was detected by following the mixing torque which reached to a steady state after passing through a maximum. The pronounced decrease in the torque was found to be determine by the thermomechanical degradation as a predominating mechanism. The polyamide 6 prepared in this work showed greater melt elasticity, much higher molecular weight and slightly narrower molecular weight distribution in comparison with the commercial grades of polyamide 6. The crystallinity of the samples was also higher than that of the commercial polyamide 6. These results were explained in terms of contribution of fraction of the molecules possessing single long chain branch formed as a result of three functional nature of the chain initiator. Increasing the rotor speed was found to have strong influence on lowering molecular weight as well as narrowing the molecular weight distribution through increasing the extent of thermomechanical degradation. Increasing the initial set temperature in the studied range had no appreciable effect on polymerization rate and degree of conversion. It was demonstrated that the results of melt viscoelastic measurements performed on the samples collected at different polymerization times can provide valuable information to follow the polymerization reaction. DOI : 10.3139/217.0074 En ligne : https://drive.google.com/file/d/16l2AvStFSEhR-K5Y1jBSM_D6WtNcDAEh/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2837
in INTERNATIONAL POLYMER PROCESSING > Vol. XXI, N° 3 (07/2006) . - p. 230-238[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 005042 - Périodique Bibliothèque principale Documentaires Disponible