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Effects of pressure and supercritical fluid on melt viscosity of LDPE in conventional and microcellular injection molding / C.-L. Hsu in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 1 (03/2012)
[article]
Titre : Effects of pressure and supercritical fluid on melt viscosity of LDPE in conventional and microcellular injection molding Type de document : texte imprimé Auteurs : C.-L. Hsu, Auteur ; Lih-Sheng Turng, Auteur ; Tim A. Osswald, Auteur ; N. Rudolph, Auteur ; E. Dougherty, Auteur ; P. Gorton, Auteur Année de publication : 2012 Article en page(s) : p. 18-24 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cisaillement (mécanique)
Etat fondu (matériaux)
Fluides supercritiques
Matières plastiques -- Moulage par injection microcellulaire
Polyéthylène basse densité
Rhéologie
ViscositéIndex. décimale : 668.9 Polymères Résumé : In this study, the flow and rheological behaviors of low density polyethylene (LDPE) and single-phase LDPE/N2 polymer/gas solutions at various gas contents were measured using a highpressure slit-die rheometer. The resulting rheology data of LDPE and LDPE/N2 were curve fit using the Cross –WLF model to obtain the seven material model constants, which were then used in the simulation of conventional and microcellular injection molding processes. The pressure effect on the shear viscosity of LDPE was also studied. The pressure dependency coefficient, D3, in the Cross –WLF model was determined by the use of simulation to best fit the experimental results. In addition, a three-dimensional plot of shear viscosity as a function of shear rate and pressure at various temperatures was constructed. Based on this three-dimensional viscosity – shear rate– temperature – pressure plot, the increase in viscosity due to the pressure effect was found to be more profound at high pressures, low temperatures, and low shear rates. Note de contenu : - PREVIOUS WORK
- EXPERIMENTAL : Slit-die rheometer - Geometric modeling for simulation - Material - Process conditions
- RESULTS AND DISCUSSION : Experimental data for neat LDPE - Temperature distribution from simulation - Viscosity pressure dependency coefficient - Experiments of LDPE/N2 solutionsDOI : 10.3139/217.2493 En ligne : https://drive.google.com/file/d/1ptY25lrbTScWYVnA8HNll5ohpIKmktDX/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13717
in INTERNATIONAL POLYMER PROCESSING > Vol. XXVII, N° 1 (03/2012) . - p. 18-24[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13722 - Périodique Bibliothèque principale Documentaires Disponible Establishment of gas counter pressure technology and its application to improve the surface quality of microcellular injection molded parts / S. C. Chen in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 3 (07/2011)
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Titre : Establishment of gas counter pressure technology and its application to improve the surface quality of microcellular injection molded parts Type de document : texte imprimé Auteurs : S. C. Chen, Auteur ; P. S. Hsu, Auteur ; Y. W. Lin, Auteur Année de publication : 2011 Article en page(s) : p. 275-282 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Matières plastiques -- Moulage par injection microcellulaire
Mousses plastiques
PolystyrèneTags : 'Contre-pression gaz' GCP 'Moulage injection microcellulaire' 'Mousse polystyrène' Index. décimale : 668.4 Plastiques, vinyles Résumé : The purpose of this study is to establish the Gas Counter Pressure (GCP) technology in combined with microcellular injection molding process. The application of gas into the mold cavity during the melt injection period provides a counter force against the melt front advancement, restricting the foaming process during the melt filling stage. Various gas counter pressures from 0 bar up to 300 bar and gas holding times of 0 to 10 s after filling completion were employed for investigating their relevant effect. It was found that when gas counter pressure is greater than 100 bar, foaming does not appear in the skin layer if no holding time is applied after melt-filling. As gas counter pressure increases, thickness of the solid skin layer without foaming also increases. Employment of holding time after melt-filling also assists foaming restriction in the melt core area. If a holding time of 10 s is applied combined with a counter pressure greater than 100 bar, foaming is completely restricted resulting in a transparent PS sample part. The part surface of those subjected to foaming-restriction in the skin layer also appears to be smooth and glossy. For the black PS parts molded via microcellular injection combined with gas counter pressure, it appears the same gloss quality as that achieved by conventional injection molding. DOI : 10.3139/217.2437 En ligne : https://drive.google.com/file/d/1n3HgCjklMlvMNw-m-OWePLgATkWTSzfG/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12406
in INTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 3 (07/2011) . - p. 275-282[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 013159 - Périodique Bibliothèque principale Documentaires Disponible Microcellular PP vs. microcellular PP/MMT nanocomposites : a comparative study of their mechanical behavior / S. J. A. Rizvi in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 4 (09/2011)
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Titre : Microcellular PP vs. microcellular PP/MMT nanocomposites : a comparative study of their mechanical behavior Type de document : texte imprimé Auteurs : S. J. A. Rizvi, Auteur ; Naresh Bhatnagar, Auteur Année de publication : 2011 Article en page(s) : p. 375-382 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Anhydride maléique
Azote
Copolymères greffés
Extrudeuse bi-vis
Fluides supercritiques
Matières plastiques -- Moulage par injection microcellulaire
Montmorillonite
Mousses plastiques -- Extrusion
Mousses plastiques -- Propriétés mécaniques
Nanoparticules
Nucléation
PolypropylèneIndex. décimale : 668.9 Polymères Résumé : Microcellular foams have attracted interest in both scientific and industrial communities. Injection molding is perhaps the most versatile industrial method of polymer processing. Microcellular injection molding is a newcomer variant in this class. It is capable to produce microcellular structure. The mechanical behavior of a microcellular polymer is different than conventional foams. Although they exhibit much improved mechanical properties than conventional foams still they are inferior to solid polymer. Incorporation of nanoparticles in matrix may affect the nucleation and bubble growth process. Further, nanoparticles will enhance the performance (stiffness, strength etc.) of matrix. In present study an effort has been made to quantitatively analyze the improvements in mechanical properties of microcellular foam with the addition of nanoclay (MMT). Nanocomposite of polypropylene and nanoclay was prepared in a co-rotating twin screw extruder. Maleic anhydride grafted polypropylene (PP-g-MA) was used as compatibilizer. PP/nanocomposites were foamed in a microcellular injection molding machine, where supercritical nitrogen (SCF-N2) was mixed with plasticized PP/ nanocomposite inside the screw – barrel assembly. The molded foamed samples were tested for various mechanical properties. Experimental results show that a considerable improvement occur in the property of microcellular polypropylene by the addition of 2 wt.% nanoclay (MMT). DOI : 10.3139/217.2375 En ligne : https://drive.google.com/file/d/1f6-1RrQ1xrQyO-cb5JWkYXr4szFJ_G6i/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12435
in INTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 4 (09/2011) . - p. 375-382[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 013208 - Périodique Bibliothèque principale Documentaires Disponible MuCell : du gaz dans le plastique / Karim Boudehane in PLASTIQUES & CAOUTCHOUCS MAGAZINE, N° 888 (10/2011)
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Titre : MuCell : du gaz dans le plastique Type de document : texte imprimé Auteurs : Karim Boudehane, Auteur Année de publication : 2011 Article en page(s) : p. 8 Langues : Français (fre) Catégories : Matériaux -- Allègement
Matières plastiques -- Moulage par injection microcellulaire
Matières plastiques dans les automobilesIndex. décimale : 668.4 Plastiques, vinyles Résumé : Ford utilise la technologie MuCell, consistant à injecter des bulles de gaz dans le plastique lors de son moulage pour réduire la quantité de polymère. Note de contenu : - Le modèle : une barre chocolatée !
- D'abord les couvercles moteursPermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=14415
in PLASTIQUES & CAOUTCHOUCS MAGAZINE > N° 888 (10/2011) . - p. 8[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13361 - Périodique Bibliothèque principale Documentaires Disponible Numerical modeling of bubble growth inmicrocellular polypropylene produced in a core-back injection process using chemical blowing agents / José Antonio Reglero Ruiz in INTERNATIONAL POLYMER PROCESSING, Vol. XXXI, N° 1 (03/2016)
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Titre : Numerical modeling of bubble growth inmicrocellular polypropylene produced in a core-back injection process using chemical blowing agents Type de document : texte imprimé Auteurs : José Antonio Reglero Ruiz, Auteur ; M. Vincent, Auteur ; Jean-François Agassant, Auteur Année de publication : 2016 Article en page(s) : p. 26-36 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Agents d'expansion (chimie)
Analyse numérique
Matières plastiques -- Moulage par injection microcellulaire
Modèles numériques
Mousses plastiques -- Moulage par injection
PolypropylèneIndex. décimale : 668.4 Plastiques, vinyles Résumé : A core-back polypropylene foaming injection process using chemical blowing agents (CBA) has been studied. First, injection tests were carried out with two different CBAs and the different morphologies of the obtained samples have been analyzed. Structural parameters such as cell density and average radius size were calculated. Then, a bubble growth model was developed to predict the foaming development during the process, controlled by the depressurization of the mold cavity during the short core-back opening coupled with the evolution of the temperature during core-back and subsequent cooling. A good agreement is found between theoretical predictions and experimental results. DOI : 10.3139/217.3129 En ligne : https://drive.google.com/file/d/1olDU5r32PXtyiuzJRC4vrDlnJgdL1X-D/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=25766
in INTERNATIONAL POLYMER PROCESSING > Vol. XXXI, N° 1 (03/2016) . - p. 26-36[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 17899 - Périodique Bibliothèque principale Documentaires Disponible The effect of polymer additives on surface quality of microcellular injection molded parts in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 4 (09/2011)
PermalinkVisualization analysis of a multilayer foam development process in microcellular injection molding / T. Yamada in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 3 (07/2012)
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