Flow marks in injection molding of PP / L. Mathieu in INTERNATIONAL POLYMER PROCESSING, Vol. XVI, N° 4 (12/2001)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVI, N° 4 (12/2001) . - p. 404-411 Titre : Flow marks in injection molding of PP : Influence of processing conditions and formation in fountain flow Type de document : texte imprimé Auteurs : L. Mathieu, Auteur ; L. Stockmann, Auteur ; Jean-Marc Haudin, Auteur ; B. Monasse, Auteur ; M. Vincent, Auteur ; J.-M. Barthez, Auteur ; Jean-Yves Charmeau, Auteur ; V. Durand, Auteur ; J. P. Gazonnet, Auteur ; D. C. Roux, Auteur Année de publication : 2001 Article en page(s) : p. 404-411 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Injection molding - Flow marks in injection moulding is quite often encountered on different type of polymers. This defects is known as successive and periodic bright and dull bands orientated perpendicular to the flow direction. Their appearances meanly depend on processing and observation conditions. This study was lead on two industrial polypropylene polymers with a simplified polished rectangular mould geometry. We show that this defect appears during the filling stage and comes from a local change of morphological and molecular orientation along the filling direction on the surface. An instability of the flow front due to limited sliding at the contact combined to the strong changed of molecular orientation before and after the stagnation point are invoked to explain this instability. DOI : 10.3139/217.1661 En ligne : https://drive.google.com/file/d/1TF2S7Ec5GinWcZV2apAO2wzBejVY9ZpI/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15925 [article]

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Numerical simulation of the injection blow molding single stage process : shaping of two different geometries and comparison with experimental thickness measurements / Jordan Biglione in INTERNATIONAL POLYMER PROCESSING, Vol. XXXI, N° 4 (08/2016)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXI, N° 4 (08/2016) . - p. 442-453 Titre : Numerical simulation of the injection blow molding single stage process : shaping of two different geometries and comparison with experimental thickness measurements Type de document : texte imprimé Auteurs : Jordan Biglione, Auteur ; Yves Bereaux, Auteur ; Jean-Yves Charmeau, Auteur Année de publication : 2016 Article en page(s) : p. 442-453 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Calorimétrie Epaisseur -- Mesure Matières plastiques -- Moulage par injection-soufflage L'injection-soufflage est un procédé de mise en forme de matériaux polymères thermoplastiques ou du verre qui est utilisé pour fabriquer des corps creux, tels des flacons et bouteilles Polypropylène Rhéométrie Simulation par ordinateur Index. décimale : 668.4 Plastiques, vinyles Résumé : Thanks to the single stage injection blow molding process, specific hollow parts can be produced with standard injection molding machine. A specific mold is designed, enabling the preform injection molding, as well as its blow molding on the same machine. The preform is blow molded right after its injection molding. This particular process does not involve preform storage and reheating before the blow molding stage. This implies that the preform has to remain sufficiently malleable to be blown while being viscous enough to avoid being pierced during the blow molding stage. The polymer used is a polypropylene random copolymer. Therefore the process takes place between the melting temperature and the crystallization one. As the preform is blow molded right after being injected, this single stage process involves high temperature before the blowing. The polymer rheological behavior is investigated through dynamic rheometry in its molten state at various temperatures. A viscous Cross model is used with the thermal dependence assumed by an Arrhenius law. The process is simulated through a finite element code (Polyflow) in the ANSYS Workbench framework. The geometry allows an axisymmetric approach. The transient simulation is run under anisothermal conditions and viscous heating is taken into account. Two geometries are simulated. First, the flask geometry has been used to show the process efficiency. The yoghurt pot geometry has been designed later for industrial application in a more sophisticated mold than the flask mold. Blow molded parts are analyzed by tomography and the thickness has been measured by the tomography data image analysis. The simulation results are compared to the experimental ones. The simulation fits well with the experimental results concerning both geometries. The simple numerical model proposed proves to be robust enough to predict well the blow molded parts final thickness repartitions provided that the relevant temperature and pressure conditions are well defined. Note de contenu : - CHARACTERIZATION : Differential scanning calorimetry - Dynamic rheometry - NUMERICAL SIMULATION : Process presentation - Modeling - Results of the numerical simulation - THICKNESS MEASUREMENT : Thickness measurement method - VALIDATION OF THE NUMERICAL MODEL DOI : 10.3139/217.3213 En ligne : https://drive.google.com/file/d/1gb5ILeJLZDKwwShkR1s8JNNq9UqcxOoL/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26806 [article]

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Visiovis : monitoring nanofiller dispersion/distribution in molten polymers / Antonella Esposito in JEC COMPOSITES MAGAZINE, N° 41 (06/2008)

[article]  inJEC COMPOSITES MAGAZINE > N° 41 (06/2008) . - p. 67-71 Titre : Visiovis : monitoring nanofiller dispersion/distribution in molten polymers Type de document : texte imprimé Auteurs : Antonella Esposito, Auteur ; Jean Balcaen, Auteur ; Jannick Duchet-Rumeau, Auteur ; Jean-Yves Charmeau, Auteur Année de publication : 2008 Article en page(s) : p. 67-71 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Matériau  composite'  'Etude  expérimentale'  'Appareil  mesure'  Fluorescence  'Degré  dispersion'  Argile  renforcé'  Dispersion  Nanocomposite  Polymère  'Etat  fondu'  Monitorage Index. décimale : 668.4 Plastiques, vinyles Résumé : The intimate mixture of nanofillers and polymers leads to an extraordinarily extended interface. However, the greatest advantage of nanocomposites becomes the main driving force for filler aggregation. This is unfortunate, as the ability to disperse nanofillers in polymers is a strict requisite for any profitable commercialization of nanocomposites. Note de contenu : - Polymer-clay nanocomposites - Visiovis - Some early results Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=14124 [article]

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