Aller sur edunet
Accueil
Mention de date : 06/2005
|
Dépouillements
Ajouter le résultat dans votre panierA dilatometer to measure the influence of cooling rate and melt shearing on specific volume / M. H. E. van der Beek in INTERNATIONAL POLYMER PROCESSING, Vol. XX, N° 2 (06/2005)
Titre : A dilatometer to measure the influence of cooling rate and melt shearing on specific volume Type de document : texte imprimé Auteurs : M. H. E. van der Beek, Auteur ; Han E. H. Meijer, Auteur ; G. W. M. Peters, Auteur Année de publication : 2005 Article en page(s) : p. 111-120 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : We developed a dilatometer to investigate the specific volume of polymers as a function of pressure (to 100MPa), temperature (to 260°C), cooling rate (to 100°C/s), and shear rate (to 801/s). The dilatometer is based on the principle of confined compression and comprises of a pressure cell used in combination with a tensile testing machine with rotation capability. The design of the pressure cell is a mixture of a traditional ‘pistondie type’ dilatometer and a Couette rheometer, i.e. piston and die make up an annular shaped sample spacing. Typical dimensions of annular samples are: inner radius ri = 10.5mm, outer radius ro = 11.0mm, height h = 2.5mm, and a typical mass of about 60 to 70mg. Silicon grease is used to reduce loss of hydrostatic pressure in the sample due to friction occurring between the solidifying sample and the dilatometer wall. Specific volume measurements at low cooling rate using an isotactic polypropylene (i-PP) are compared with measurements performed using a commercial bellows type dilatometer, showing relative differences in the range of 0.1 to 0.4%. Finally, results for an isotactic polypropylene are presented showing a profound influence of cooling rate and melt shearing on the evolution of specific volume. DOI : 10.3139/217.1872 En ligne : https://drive.google.com/file/d/1Bo9V5oP1mUrdWVg2yWcFXJK00M-H5eHK/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3070
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 111-120[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Monitoring reactive processes along the extruder Type de document : texte imprimé Auteurs : Jose A. Covas, Auteur ; A. V. Machado, Auteur Année de publication : 2005 Article en page(s) : p. 121-127 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : This paper reports data obtained from monitoring the evolution of chemical conversion and morphology during the production of a compatibilized polymer blend of PA 6/EPM/EPM-g-MA and of modified polyolefins (grafted with MA) in a co-rotating twin screw extruder. In the first case, the MA content of the modified rubber decreases strongly to almost zero-level and the particle size reduces dramatically from mm to sub-lm level already in the melting zone. The process seems to be mainly influenced by the local flow characteristics, as they assure efficient generation and renewal of interfacial area. In the second case of MA grafting, a similar evolution is observed regardless of the polyolefin type but, for this kind of reactions, temperature and residence time play an important role. A brief presentation of the on-line monitoring tools used in the above studies is also included. DOI : 10.3139/217.1871 En ligne : https://drive.google.com/file/d/1rS4PQwOOJmuNKo7G4otU7N62YRSjzyDe/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3071
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 121-127[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Stretch and shape distributions of droplets with interfacial tension in chaotic mixing Type de document : texte imprimé Auteurs : T. N. Pham, Auteur ; C. L. Tucker, Auteur Année de publication : 2005 Article en page(s) : p. 128-135 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : A numerical simulation is developed to study the time-dependent shapes of droplets in chaotic mixing, as a function of interfacial tension and droplet-to-matrix viscosity ratio. The two-dimensional, time-periodic Newtonian flow between eccentric cylinders is used as a prototype mixing flow. The microstructure is modeled as three-dimensional ellipsoidal droplets, ignoring breakup and coalescence. A Lagrangian particle method is used to follow the microstructure. When interfacial tension is small (global capillary number is large), the major axes of the droplets exhibit the same stretching statistics as passive fluid elements and droplets with zero interfacial tension in chaotic flows: the geometric average of the stretch ratio grows exponentially with time, at a rate equal to the Lyapunov exponent of the flow, while the log of the major-axis stretch of the droplets, when scaled by its instantaneous mean and standard deviation, has a time-invariant, Gaussian global distribution and a non-uniform, fractal, and time-invariant spatial distribution. In this regime the stretch of the longest droplet axis is insensitive to interfacial tension, but the shape of the cross section is very sensitive: initially spherical droplets deform first into ribbons or sheets, but eventually transform into axisymmetric threads. The larger the global capillary number, the longer the sheet morphology persists, but sheet-like structures are always transient, and the sheets relax to threads if mixing goes on too long. DOI : 10.3139/217.1880 En ligne : https://drive.google.com/file/d/1AksxJbYIFQbKwXA4QlibS3G6233xiHjr/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3072
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 128-135[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Cast film extrusion : An overview of experimental and theoretical approaches Type de document : texte imprimé Auteurs : Jean-François Agassant, Auteur ; D. Silagy, Auteur ; Cyrille Sollogoub, Auteur ; Y. Demay, Auteur Année de publication : 2005 Article en page(s) : p. 136-148 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Cast film extrusion is a widely used technique to produce polymer films for packaging or coating applications. The final width of the film may be smaller than the initial die width (necking phenomenon) and therefore is the final film thickness larger than what one could expect. Moreover it is heterogeneous (in terms of showing a larger thickness along the borders, also called dog bone defect). Above a critical draw ratio between the chill roll and the die both width and thickness fluctuations are observed (Draw Resonance Instability). All these phenomena limit the productivity of the process. This paper provides an overview of the processing and material parameters governing the development of these geometrical defects and instabilities. Numerical models capturing the main experimental features are proposed, allowing to investigate process modifications in order to limit the development of these defects. DOI : 10.3139/217.1874 En ligne : https://drive.google.com/file/d/18NFGRvtS8JN94uTvKOfK2Ep9NBeqzCNY/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3073
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 136-148[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Nozzle injection of physical blowing agents in the injection molding of microcellular foams Type de document : texte imprimé Auteurs : V. L. Bravo, Auteur ; Andrew N. Hrymak, Auteur Année de publication : 2005 Article en page(s) : p. 149-156 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Results obtained from the implementation of a physical foaming system for injection molding are presented. The implemented design involves the injection of gas in the upstream side of a special nozzle composed by a static mixing element (SMX type) and a shut-off valve. In order to avoid the formation of large pockets of gas in the injection point, a porous metal plug is used to create a multiple point injection area with 20µm size pores. Gas injection simultaneously with polymer melt injection gave a consistent foamed material. However, given the total pressure drop in the system of static mixers, runners and mold, there is an inherent operational pressure limitation. The polymer injection pressure needs to be kept at a pressure below the gas injection pressure, therefore limiting the speed at which the polymer can be injected in the mold. DOI : 10.3139/217.1879 En ligne : https://drive.google.com/file/d/1FXjggkPmVbWQYDe3QOMmecwqo9bZpott/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3074
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 149-156[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Visualization analysis of asymmetric fountain flow phenomenon in injection molding of filler-reinforced resins by rotary runner exchange system Type de document : texte imprimé Auteurs : H. Yokoi, Auteur ; Y. Kanetoh, Auteur Année de publication : 2005 Article en page(s) : p. 157-161 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : In this study, we attempted to visualize the flow patterns inside molded samples of glass-fibers or talc reinforced GPPS and PP especially in the vicinity of the flow front, using a rotary runner exchange system which instantaneously switches melt flowing into the cavity. From the visualization results, an extremely characteristic flow behavior was seen at the flow front area for resins with fillers which was not observed for those without fillers. Especially in the case of resins with 40 wt.% talc or 30 wt.% GF, a-symmetric zigzag fountain flows were generated alternately upward and downward along the cavity width direction. Moreover along the outer layer of the flow front, one observed a large amount of residual resin remaining for a long time during the cavity filling process, in the case of 40 wt.% GF, primarily due to the increase of viscosity which restricts the occurrence of diverging flow. Based on the above visualization results, we proposed a generic model of zigzag fountain flow; an a-symmetric upward flow in a certain area starts preventing the fountain flow in the upper side of the adjacent area, causing the diverging center to sink. This phenomenon subsequently causes an a-symmetric flow in the opposite direction in the next adjacent area, which continuously propagates along the cavity width direction. DOI : 10.3139/217.1875 En ligne : https://drive.google.com/file/d/1VqXzreoqEXJDat_AznmBOZpOFGuW5Y-r/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3075
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 157-161[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : In-process monitoring of micromoulding – assessment of process variation Type de document : texte imprimé Auteurs : B. R. Whiteside, Auteur ; P. D. Coates, Auteur ; Mike T. Martyn, Auteur Année de publication : 2005 Article en page(s) : p. 162-169 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Advances in micromoulding technology are leading to complex, net-shape products having sub-milligramme masses with micro-scale surface features in a range of polymer and nanocomposite materials. For such small components subjected to the extreme stress, strain-rate and temperature gradients encountered in the micromoulding process, detailed process monitoring is desirable to highlight variations in moulding conditions and assist in creating a viable manufacturing process with acceptable quality products. This paper covers the implementation of a suite of sensors on a commercial micromoulding machine and detailed computer monitoring during processing of a polyacetal component over a range of processing conditions. The results determined that cavity pressure curve integral data provides the most sensitive factor for characterisation of a moulding process of a 0.34mm3 (0.49mg) product. The repeatability of the process is directly compared with that of a 15.6mm3 (22.2mg) product and shown to be inferior. DSC measurements of the whole products indicated little variation in average crystallinity of the products manufactured over a mould temperature range of 30 to 130°C. DOI : 10.3139/217.1876 En ligne : https://drive.google.com/file/d/1GBlj5iRVKeyUDCaJsfWi3Nv8-j-bJaL7/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3076
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 162-169[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Processing-induced properties in glassy polymers : Development of the yield stress in PC Type de document : texte imprimé Auteurs : L. E. Govaert, Auteur ; T. A. P. Engels, Auteur ; E. T. J. Klompen, Auteur ; G. W. M. Peters, Auteur ; Han E. H. Meijer, Auteur Année de publication : 2005 Article en page(s) : p. 170-177 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : A new method is employed to directly predict the development of yield stress distributions in injection molded products of glassy polymers. The approach is based on the results of a study on the temperature dependence of the evolution of yield stress during annealing of polycarbonate below Tg. In combination with the process-related thermal history, derived from numerical simulations of the injection molding process, an estimate of the yield stress distribution throughout a product can be obtained. Computed yield stresses of injection molded plates prove to be in excellent agreement with the experimental values, including their dependence on mold temperature and plate thickness. DOI : 10.3139/217.1870 En ligne : https://drive.google.com/file/d/1OkBTt086QwaCbTCcCoQp8JKLxm4SKJIT/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3077
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 170-177[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Structure development in injection molding : A 3D simulation with a differential formulation of the kinetic equations Type de document : texte imprimé Auteurs : J. Smirnova, Auteur ; Jean-Marc Haudin, Auteur ; J.-L. Chenot, Auteur ; B. Monasse, Auteur ; L. Silva, Auteur Année de publication : 2005 Article en page(s) : p. 178-185 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The purpose of the present work is to introduce a crystallization law into Rem3D, a 3D code written in C++ and dedicated to the injection molding of polymers. We kept the basic hypotheses of Avrami’s model and cast the kinetic equations into a differential system that is solved numerically. The variation of the density of potential nuclei with temperature is taken into account. Furthermore, the distribution of mean spherulite sizes can be deduced from the calculations. The second part of the paper is an experimental study of crystallization in well-controlled conditions (2D, isothermal or constant cooling-rate). It establishes a procedure for the determination of the nucleation and growth parameters used in the theoretical model, and gives a first validation of this model. Finally, the crystallization equations are introduced into Rem3D, in order to assess the feasibility of our new approach. Some typical results concerning the evolution of the transformed volume fraction in injection-molded parts are presented. DOI : 10.3139/217.1873 En ligne : https://drive.google.com/file/d/1g_0Bi-rQei21aYdF2fLHNmTclWCrnS0F/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3078
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 178-185[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Evolution of morphology of iPP in processing conditions : Relevance of solidification pressure Type de document : texte imprimé Auteurs : I. Coccorullo, Auteur ; G. Titomanlio, Auteur ; R. Pantani, Auteur Année de publication : 2005 Article en page(s) : p. 186-190 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : A model for crystallization kinetics that accounts for the formation of different crystalline phases and is able to describe the morphological characteristics of samples solidified under quiescent conditions, has been enriched to account for the effect of solidification pressure. The effect of pressure was considered by assuming a linear increase of melting and glass transition temperatures (which are involved in the description of the growth rate and nucleation density of the alpha phase). Moreover, pressure was incorporated in the kinetic constant adopted to describe the evolution of the mesomorphic phase. The parameters of the model were identified on the basis of literature data on the distribution of crystalline phases in samples solidified under different pressures. The modified model also satisfactorily described PVT curves up to 100MPa, and is now able to describe the evolution of morphology during solidification at cooling rates as fast as several hundreds of Kelvin degrees per second and under pressures of as high as 100MPa. DOI : 10.3139/217.1877 En ligne : https://drive.google.com/file/d/1MU0nmmxwVQ7tBh-DdIgxGkunDd7jIRT1/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3079
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 186-190[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : 3D simulation of gas assisted injection molding analysis of primary and secondary gas penetration and comparison with experimental results Type de document : texte imprimé Auteurs : A. Polynkin, Auteur ; J. Sienz, Auteur ; J. F. T. Pittman, Auteur Année de publication : 2005 Article en page(s) : p. 191-201 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Techniques for the three dimensional simulation of gas assisted injection molding (GAIM) are presented, including analysis of primary and secondary gas penetration and the use of time and position dependent heat transfer boundary conditions, computed in a segregated 3D analysis of conduction in the tool, through many cycles of moulding. Predictions are compared with results of experimental trials using a mould tool with a glass window that allows video recording of the process. Accurate agreement is obtained for gas penetration distances in primary and secondary penetration and for the forms of the gas channel cross sections, in a part that incorporates typical features of a GAIM application. The success of the simulations relies on careful detailing of the computational model and numerical procedures, including the use of dynamically updated flow and heat transfer boundary conditions, the use of sufficiently high resolution meshes, and efficient, high accuracy iterative solution techniques. DOI : 10.3139/217.1878 En ligne : https://drive.google.com/file/d/1uwhXsKk0lkdytilr4nIqRTQMAXRHvXdf/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3080
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 191-201[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Microcellular injection molding Type de document : texte imprimé Auteurs : S. Gong, Auteur ; Lih-Sheng Turng, Auteur ; A. Osorio, Auteur ; H. Kharbas, Auteur ; A. Chandra, Auteur ; M. Yuan, Auteur Année de publication : 2005 Article en page(s) : p. 202-214 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : This paper reviews some of the recent developments of microcellular injection molding, which is capable of producing parts with excellent dimensional stability using lower injection pressure, shorter cycle time, and less material. Process conditions as well as nano/micro-fillers such as nanoclay and core–shell rubber have a strong influence on cell density and cell size, hence, the final material properties of the molded parts. The addition of nano/micro-fillers at optimum loading levels can generally facilitate the formation of microcellular plastics with higher cell density and smaller cell size leading to superior mechanical properties. The novel integration of a solid plastic surface with a microcellular plastic core via the co-injection molding technique has been investigated to achieve Class “A” surfaces and improved material performance. An improved mathematical model has been developed to simulate the cell growth behavior in the microcellular injection molding process. DOI : 10.3139/217.1883 En ligne : https://drive.google.com/file/d/1tNvJwDvWFCky3KsVs2MkLFhq5fYBNXwz/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3081
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 202-214[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Effect of material species on flash generation of PPS/GF composites Type de document : texte imprimé Auteurs : H. Higuchi, Auteur ; K. Koyama, Auteur ; H. Goto, Auteur Année de publication : 2005 Article en page(s) : p. 215-223 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Reduction of flash in injection molding is of great concern for manufacturers of electrical parts. In a previous report we have proposed a theoretical model for flash generation. The present study prepares five different poly(phenylene sulfide)/glass fiber composites using three different PPS; linear, branched and crosslinked PPS and measures the length of flash generated in the molding of the composites. Then, we have compared the flash data with a flash parameter defined in the model. This comparison has elucidated that flash length can be related with the flash parameter irrespective of PPS structure, as long as GF content is the same and the clearance of a gas vent is almost identical. DOI : 10.3139/217.1885 En ligne : https://drive.google.com/file/d/1mbDrGziW9oucOQG6HWTN6FJoNwVQRe3H/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3082
in INTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 215-223[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 001970 - Périodique Bibliothèque principale Documentaires Disponible
Exemplaires (1)
| Code-barres | Cote | Support | Localisation | Section | Disponibilité |
|---|---|---|---|---|---|
| 001970 | - | Périodique | Bibliothèque principale | Documentaires | Disponible |
