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INTERNATIONAL POLYMER PROCESSING / Polymer Processing Society . Vol. XVII, N° 2Mention de date : 06/2002Paru le : 01/06/2002 |
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Ajouter le résultat dans votre panierA new method for simulating the conveying of solid pellets / K. L. Yung in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
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Titre : A new method for simulating the conveying of solid pellets Type de document : texte imprimé Auteurs : K. L. Yung, Auteur ; Y. Xue, Auteur ; K. H. Lau, Auteur Année de publication : 2002 Article en page(s) : p. 91-94 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : A new method for simulating the solid conveying process in plasticating machine is proposed in this paper. The new simulation method is superior to previous ones by having the ability in modeling the movements, in any direction, of solid pellets of any geometry or whether it is densely or sparsely packed. New normal and tangential contact force models are introduced. With the new method the solid conveying process are simulated more realistically. In the simulation, the effects of velocity of the barrel, the sliding frictions of the pellets against the barrel and the screw walls with respect to the solid conveying speed are studied, which coincide with empirical results Note de contenu : - SIMULATION METHOD
- CONTACT FORCE MODELS
- CONTACT IDENTIFICATIONSDOI : 10.3139/217.1689 En ligne : https://drive.google.com/file/d/17GNRn6zQ2UHF7NAm8G5mE1RUkGljzyz4/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15927
in INTERNATIONAL POLYMER PROCESSING > Vol. XVII, N° 2 (06/2002) . - p. 91-94[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible A 3D numerical study of fluid flow and heat transfer in a single screw extruder / D. -S. Kwag in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
[article]
Titre : A 3D numerical study of fluid flow and heat transfer in a single screw extruder Type de document : texte imprimé Auteurs : D. -S. Kwag, Auteur ; M.-Y. Lyu, Auteur ; W.-S. Kim, Auteur Année de publication : 2002 Article en page(s) : p. 95-101 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : A numerical study of three-dimensional fluid flow and heat transfer in the metering section of a single screw extruder has been performed. The screw channel was simplified by unwinding the channel and the coordinate system was fixed on the screw root in the present model. The pressure distribution over the inlet region was to be extrapolated from the solution of interior pressure. The prescribed mass flow rate was imposed on the outlet of the unwinding screw channel. The three-dimensional velocity fields, temperature, viscosity, and pressure profiles in the screw channel were calculated by using the commercial code, STAR-CD, based on the finite volume method. Some of the results of the present full 3D model were compared with the results from the marching-type 3D model. It is shown that the present work can capture the back flow by the pressure gradient near the screw root in the cases of small mass flow rates. There exist significant discrepancies in temperature between the marching-type 3D model and the present 3D model. The present work well describes the effects of heating-up through the circulation flow and viscous dissipation. The cross-section contours of velocities, temperature, viscosities and pressures along the down-channel direction are also shown in this study. DOI : 10.3139/217.1686 En ligne : https://drive.google.com/file/d/1WN8q1FlUj0fzKd4fk93iFe4m-NsS8Khh/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15928
in INTERNATIONAL POLYMER PROCESSING > Vol. XVII, N° 2 (06/2002) . - p. 95-101[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible Pressure/throughput behavior of a single-screw plasticising unit in consideration of wall slippage / H. Potente in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
[article]
Titre : Pressure/throughput behavior of a single-screw plasticising unit in consideration of wall slippage Type de document : texte imprimé Auteurs : H. Potente, Auteur ; H. Ridder, Auteur Année de publication : 2002 Article en page(s) : p. 102-107 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The mathematical models so far available for describing the throughput behavior of plasticising extruders were developed with the assumption of a wall-adhering melt. There are, however, a series of plastic melts, and also elastomers, polymer suspensions, ceramic materials and food products that display wall slippage during processing. A mathematical model has been developed for this material behavior, which describes the flow behavior for unidimensional, Newtonian, isothermal case.
Apart from the development of the analytical model, the flow behavior of wall-slipping polymer melts was also analysed with the aid of finite element calculations (FEM). A comparison of the results for the pressure/throughput behavior shows that the calculation results tally very well for the two methods. It is thus possible to develop a procedure which makes it possible to describe the phenomenon of wall-slippage for the non-Newtonian, multi-dimensional, non-isothermal case.DOI : 10.3139/217.1679 En ligne : https://drive.google.com/file/d/1wuIdRw8avymEWtIsdIBs3hC42pImEXiy/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15929
in INTERNATIONAL POLYMER PROCESSING > Vol. XVII, N° 2 (06/2002) . - p. 102-107[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible Computational study of the velocity field in the conveying element of a ko-kneader with CFD method / M. Mehranpour in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
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Titre : Computational study of the velocity field in the conveying element of a ko-kneader with CFD method Type de document : texte imprimé Auteurs : M. Mehranpour, Auteur ; H. Nazokdast, Auteur ; B. Dabir, Auteur Année de publication : 2002 Article en page(s) : p. 108-114 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Single extrusion - An attempt has been made to predict the velocity field in the conveying element of a Ko-Kneader using CFD method. The effects of both rotating and reciprocating motions of the screw have been taken in to account in three dimensional flow analysis. It has been demonstrated that such computational method can provide a great insight into visualization of the flow field in this element of a Ko-Kneader. Among the variables the reciprocating action was found to play a significant role on enhancing the mixing performance of the Ko-Kneader by means of periodical changing the flow field and shear rate distribution in the channel. DOI : 10.3139/217.1680 En ligne : https://drive.google.com/file/d/1MSQazWalZvbM9miMbb3YG8eFgoxNNwtH/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15930
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible Modification of polyolefin with maleic anhydride/styrene and methyl methacrylate/styrene / J. Cha in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
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Titre : Modification of polyolefin with maleic anhydride/styrene and methyl methacrylate/styrene Type de document : texte imprimé Auteurs : J. Cha, Auteur ; J. L. White, Auteur Année de publication : 2002 Article en page(s) : p. 115-123 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : There has been little effort to quantitatively understand the simultaneous graft copolymerization of two monomers in batch and continuous mixers. In this study maleic anhydride/styrene and methyl methacrylate/styrene monomer pairs were grafted onto polypropylene in both an internal mixer and a twin screw extruder. There is little information on the evolution of grafting reactions of dual monomers with respect to time in an internal mixer and along the screw axis in a twin screw extruder. The influence of reaction time in an internal mixer and residence time in a twin screw extruder on degree of grafting was measured. The dependence of the degree of grafting with respect to ratio of comonomer concentration was determined. A kinetic scheme was proposed and experimentally tested. Note de contenu : - EXPERIMENTAL : Materials - Grafting in an internal mixer - Grafting in a twin screw extruder - Determination of monomer incorporation onto PP
- RESULTS : Internal mixer - Twin screw extruder - Melt viscosityDOI : 10.3139/217.1687 En ligne : https://drive.google.com/file/d/1dglDBRWVbYDrJk9-qFUMNzeHDup9Nopw/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15931
in INTERNATIONAL POLYMER PROCESSING > Vol. XVII, N° 2 (06/2002) . - p. 115-123[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible Direct measurement of fiber temperature in the continuous drawing process of PET fiber heated by CO2 laser radiation / W. Okumura in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
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Titre : Direct measurement of fiber temperature in the continuous drawing process of PET fiber heated by CO2 laser radiation Type de document : texte imprimé Auteurs : W. Okumura, Auteur ; T. Yamaguchi, Auteur ; Y. Ohkoshi, Auteur ; Y. Gotoh, Auteur ; M. Nagura, Auteur Année de publication : 2002 Article en page(s) : p. 124-132 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Poly(ethylene terephtalate) (PET) fiber was heated by carbon dioxide laser radiation during the continuous drawing process. Numerical calculation shows that the PET fiber can be heated much more rapidly and uniformly by heat radiation than by convective heat transfer through the fiber surface. During CO2 laser heated drawing, temperature in the vicinity of a neck-like deformation can be measured on-line with high precision, because the neck-like deformation is located within a range of 0.5 mm. We measured the fiber temperature profiles on the drawing process by IR thermometer that has a range resolution of 0.355 mm. The temperature at which neck-like deformation of the fiber initiates is higher than Tg when draw ratio is less than 4.5, but lower than Tg when draw ratio is more than 5.5. The maximum fiber temperature in the drawing process increases with draw ratio, up to 208°C for a draw ratio of 6.0. The rate of orientation-induced crystallization in the drawing process was estimated by comparison of measured temperature profiles with calculated temperature profiles. Note de contenu : - EXPERIMENTAL : Drawing system and material - Drawing tension - Density - Fiber temperature
- DISCUSSION : Comparison of radiation heating and conduction heating from fiber surface - Numeraical calculation of fiber temperature profiles
- APPENDIX : Absorption coefficient - Temperature distribution in the fiber cross-section - Absorptance of fiberDOI : 10.3139/217.1684 En ligne : https://drive.google.com/file/d/1eOzKEBB28dFq9HOJwrpxLtnhdtZ96iWb/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15932
in INTERNATIONAL POLYMER PROCESSING > Vol. XVII, N° 2 (06/2002) . - p. 124-132[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible Evaluation of a model describing the advancing flow front in injection moulding / F. Pisciotti in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
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Titre : Evaluation of a model describing the advancing flow front in injection moulding Type de document : texte imprimé Auteurs : F. Pisciotti, Auteur ; A. Boldizar, Auteur ; M. Rigdahl, Auteur ; G. Aronsson, Auteur ; M. Rigdahl Année de publication : 2002 Article en page(s) : p. 133-145 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The simulation of the advancing flow front during mould filling in the injection moulding cycle is important as a way of anticipating manufacturing defects, particularly different types of welds, air traps, cold spots and hot spots. The purpose of the present work was to evaluate a model (the distance model) simulating the advancing flow front and predicting potential issues related to the progression of the flow front such as welds and air traps. The distance model is based on a mathematical theory of Hele-Shaw flow for strongly shear-thinning fluids, i. e. fluids with a power-law index, n, equal to 0,3 or preferably less. Two grades of general-purpose polystyrene were selected according to their abilities to shear thin (weakly or moderately strong) at the selected processing temperature and in the typical shear rate range of the injection moulding process. The two grades were injection moulded into twelve mould configurations derived from two similar single-gated moulds. The flow length from the gate to the weld was measured in the mouldings obtained at three distinct rates of filling (conventional, slower and faster) and compared to the flow lengths obtained by the distance model. Good agreement was found between the predicted flow lengths and the experimental flow lengths at the conventional and faster filling conditions. Larger deviations between simulation and experiment were found at the slower filling rate, particularly for the weakly shear-thinning polystyrene grade. Some comparisons were also made with the predictions obtained using the commercial simulation code Moldflow. A comparison between the advancing front predictions of the distance model and experimental short shots of a commercial polypropylene grade in a lure-box type of mould geometry showed that the distance model, despite its simplicity, could probably be used to detect welds and air traps in more complex and practice-related mouldings. Note de contenu : - INTRODUCTION : Manufacturing defects related to mould filling - The distance model -
- EXPERIMENTAL : Materials - Mould geometry - Processing - Flow length measurement
- RESULTS AND DISCUSSION : Weld detection - The advancing flow front - A practice-related mouldingDOI : 10.3139/217.1682 En ligne : https://drive.google.com/file/d/15mW8TQTMJGeBpUZ0EWylo9zGHAYQhFm4/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15942
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible Process design for reducing the warpage in thin-walled injection molding / T.-H. Wang in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
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Titre : Process design for reducing the warpage in thin-walled injection molding Type de document : texte imprimé Auteurs : T.-H. Wang, Auteur ; W.-B. Young, Auteur ; J. Wang, Auteur Année de publication : 2002 Article en page(s) : p. 146-152 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The process design of the thin-walled injection molding is investigated in this study. It was realized that the behavior of warpage in injection molding parts was affected by different process conditions such as melt temperature, mold temperature, packing pressure and injection rate. Experimental design of Taguchi method was used to determine the process conditions. Both the numerical simulations and experiments were conducted to study the effects of the process conditions on the warpage of a cap model. The proper processing parameters were also identified by experimental design. The packing pressure was found to be the most important factor on the warpage of a thin-walled part. The experimental design done by numerical simulations also provided proper results in terms of warpage reduction. DOI : 10.3139/217.1688 En ligne : https://drive.google.com/file/d/1sx4RxXZdbofgRmD-k5rXoqcpAUhtjK-_/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15943
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible Preferable filament diameter ratios of hybrid yarn components for optimized longfiber reinforced thermoplastics / R. Beyreuther in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
[article]
Titre : Preferable filament diameter ratios of hybrid yarn components for optimized longfiber reinforced thermoplastics Type de document : texte imprimé Auteurs : R. Beyreuther, Auteur ; Harald Brünig, Auteur ; R. Vogel, Auteur Année de publication : 2002 Article en page(s) : p. 153-157 Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The mechanical properties of hybrid (commingled) yarn based reinforced thermoplastics depend on many parameters of the fiber components as well as of the different technological conditions during the commingling and the hot press molding. Among the fiber parameters the diameter ratio of the matrix and the reinforcing yarn components are most important to obtain the best mechanical properties of the reinforced thermoplastics. The paper treats theoretical considerations in order to reach a high probability of coating each reinforcing filament with the thermoplastic material during the hot press molding. The calculations include the filament ratios and the achieved volume ratios of both hybrid yarn components of the finished reinforced thermoplastics. It is demonstrated the under different optimization criterias (same filament numbers for both components or the same surfaces of the reinforcing yarn filaments and the matrix yarn filaments before the hot press molding) a more or less small range of filament ratios seem to be valid for manufacturing a homogeneous faultless reinforced thermoplastic. Quantitative calculations for two hybrid yarn systems PEEK/carbon fibers and PP/glass fibers, presented in diagrams, are demonstrated. Technological conditions for the spinning of micro fibers like PEEK-filaments complete the presentation. Note de contenu : - Theoretical investigations concerning the diameter ratios
- Melt spinning of microfiber like filamentsDOI : 10.3139/217.1681 En ligne : https://drive.google.com/file/d/1oJ5tJPe_RPFD7bm5BN7eeig3Rhdh8Xio/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15944
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible Squeeze flow rheology of glass mat thermoplastic (GMT) in large tools and at high closing velocities / C. F. Vahlund in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
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Titre : Squeeze flow rheology of glass mat thermoplastic (GMT) in large tools and at high closing velocities Type de document : texte imprimé Auteurs : C. F. Vahlund, Auteur ; B. R. Gebart, Auteur Année de publication : 2002 Article en page(s) : p. 158-165 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Rheological measurements on material with fibre-like inhomogenities will be significantly affected by sample size when the in-plane dimensions of the sample are comparable with the length of the fibres. In this paper, a 310 t hydraulic press has been modified for squeeze flow rheology studies so that large tools that will minimize the influence of sample size can be used in combination with high closing velocities. Isothermal squeeze flow rheology experiments of GMT have been performed for closing velocities up to 30 mm/s corresponding to maximum closing forces of 1000 kN. Successful power law fits of closing velocity versus closing force have been performed for the velocity interval. Four different analytical models have been fitted to the experimental data and the accuracy in these has been investigated. The force prediction of the biaxial extension model is acceptable for the major part of mould closure, but better fits during the last part of mould closure were obtained using an additive model incorporating both shear and extensional flow. DOI : 10.3139/217.1683 En ligne : https://drive.google.com/file/d/1IFCqFxdKfB7T4QYPHvBg2xwvVFN1rm6u/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15945
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Code-barres Cote Support Localisation Section Disponibilité 001020 - Périodique Bibliothèque principale Documentaires Disponible Analysis of heat flux from molten polymers to molds in injection molding processes / Y. Shiraishi in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)
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Titre : Analysis of heat flux from molten polymers to molds in injection molding processes Type de document : texte imprimé Auteurs : Y. Shiraishi, Auteur ; H. Norikane, Auteur ; N. Narazaki, Auteur ; Takeshi Kikutani, Auteur Année de publication : 2002 Article en page(s) : p. 166-175 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The inverse analysis method is applied in the evaluation of heat flux at the interface between the molten polymer and the mold during the injection molding process. In addition, the dependence of cooling behaviour on both the molding conditions and the material properties of the resin are investigated. During low-velocity polymer flow in the thick regions of the mold cavity, the heat flux in the later stage of the process evaluated through experiment correlates well with the theoretical results of equations describing heat conduction at the interface of two semi-infinite objects. In contrast, in the thin region of the mold cavity, the analyzed heat flux is greater than the theoretical result for high-velocity polymer flow, and the difference expands with an increase in the shear rate at the wall of the mold. Based on these results, a simple empirical equation applicable to a wide range of molding conditions is proposed for the estimation of heat flux at the polymer-mold interface. Note de contenu : - INVERSE HEAT CONDUCTION ESTIMATION PROCEDURE
- EXPERIMENTAL : Specifications of the probe - Estimation of the thermal properties of the probe - Experimental conditions in the injection molding process
- RESULTS AND DISCUSSION : Estimation of the thermal properties of the probe - Optimization of the IHCP parameters - Heat flux during the injection molding process - Effect of molding conditions - Derivation of an empirical equationDOI : 10.3139/217.1685 En ligne : https://drive.google.com/file/d/1j6LG1kSF357QlYaQwK9unZS5X8G8KAcW/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15946
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