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INTERNATIONAL POLYMER PROCESSING / Polymer Processing Society . Vol. 37, N° 4Mention de date : 2022Paru le : 06/09/2022 |
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Ajouter le résultat dans votre panierCalendering of thermoplastics : models and computations / Evan Mitsoulis in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
[article]
Titre : Calendering of thermoplastics : models and computations Type de document : texte imprimé Auteurs : Evan Mitsoulis, Auteur ; Nickolas D. Polychronopoulos, Auteur ; Savvas G. Hatzikiriakos, Auteur Année de publication : 2022 Article en page(s) : p. 341-356 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Calandrage Le calandrage est une opération qui consiste à faire passer un matériau entre deux cylindres pour le lisser ou le lustrer, ou pour produire un film ou une feuille. Des matériaux de plus faible épaisseur (produits semi-finis, feuilles, plaques, films, crêpes) peuvent être obtenus par calandrage d'un système thermoplastique ou élastomère entre des cylindres éventuellement chauffants.
Une calandreuse comporte au moins deux rouleaux contrarotatifs, dont l'écartement est ajustable. Plusieurs passages entre les cylindres peuvent être réalisés.
Cette opération est par exemple utilisée pour fabriquer des revêtements de sols et de murs, des nappes, de l'ameublement, de la maroquinerie et des articles gonflables.
Pour les pâtes de faible viscosité, une calandreuse peut servir de mélangeur en formulation.
En papeterie, l'opération de calandrage permet d'obtenir différents états de surface de la feuille de papier, notamment pour les papiers couchés. Selon le degré de calandrage (pression, température de chauffe), le papier sera plus ou moins lissé et brillant.
Calcul
Modèles mathématiques
Simulation par ordinateur
ThermoplastiquesUne matière thermoplastique désigne une matière qui se ramollit (parfois on observe une fusion franche) d'une façon répétée lorsqu'elle est chauffée au-dessus d'une certaine température, mais qui, au-dessous, redevient dure. Une telle matière conservera donc toujours de manière réversible sa thermoplasticité initiale. Cette qualité rend le matériau thermoplastique potentiellement recyclable (après broyage). Cela implique que la matière ramollie ne soit pas thermiquement dégradée et que les contraintes mécaniques de cisaillement introduites par un procédé de mise en forme ne modifient pas la structure moléculaire.Index. décimale : 668.4 Plastiques, vinyles Résumé : John Vlachopoulos (JV) started his polymer processing career with the process of calendering. In two landmark papers with Kiparissides, C. and Vlachopoulos, J. (1976). Finite element analysis of calendering. Polym. Eng. Sci. 16: 712–719; Kiparissides, C. and Vlachopoulos, J. (1978). A study of viscous dissipation in the calendering of power-law fluids. Polym. Eng. Sci. 18: 210–214 he introduced the Finite Element Method (FEM) to solve the governing equations of mass, momentum, and energy based on the Lubrication Approximation Theory (LAT). This early work was followed by the introduction of wall slip (with Vlachopoulos, J. and Hrymak, A.N. (1980). Calendering poly(vinyl chloride): theory and experiments. Polym. Eng. Sci. 20: 725–731). The first 2-D simulations for calendering PVC were carried out with Mitsoulis, E., Vlachopoulos, J., and Mirza, F.A. (1985). Calendering analysis without the lubrication approximation. Polym. Eng. Sci. 25: 6–18. In the intervening 35 years, other works have emerged, however our understanding has not been drastically improved since JV’s early works. Results have also been obtained for pseudoplastic and viscoplastic fluids using the general Herschel-Bulkley constitutive model. The emphasis was on finding possible differences with LAT regarding the attachment and detachment points of the calendered sheet (hence the domain length), and the extent and shape of yielded/unyielded regions. The results showed that while the former is well predicted by LAT, the latter is grossly overpredicted. More results have been obtained for 3-D simulations, showing intricate patterns in the melt bank. Also, the transient problem has been solved using the ALE-FEM formulation for moving free-boundary problems. The results are compared with the previous simulations for the steady-state and show a good agreement. The transient simulations capture the movement of the upstream and downstream free surfaces, and also provide the attachment and detachment points, which are unknown a priori. Finding these still remains the prevailing challenge in the modeling of the calendering process. Note de contenu : - MATHEMATICAL MODELING
- GOVERNING EQUATIONS (LAT) : Sheet thickness - Operating variables
- RESULTS AND DISCUSSION : Viscoplastic fluids - Time-dependent simulationsDOI : https://doi.org/10.1515/ipp-2021-4214 En ligne : https://drive.google.com/file/d/1v_BYkY3dn_Pyy17u6SMSe9mtBAyzszgT/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37911
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Code-barres Cote Support Localisation Section Disponibilité 23739 - Périodique Bibliothèque principale Documentaires Disponible Film casting of polycarbonate/multi-walled carbon nanotubes composites using ultrasound-assisted twin-screw extruder: experiment and simulation / Xiang Gao in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
[article]
Titre : Film casting of polycarbonate/multi-walled carbon nanotubes composites using ultrasound-assisted twin-screw extruder: experiment and simulation Type de document : texte imprimé Auteurs : Xiang Gao, Auteur ; Avraam I. Isayev, Auteur Année de publication : 2022 Article en page(s) : p. 357-371 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Composites à fibres -- Extrusion
Composites à fibres de carbone
Essais (technologie)
Films plastiques
Nanotubes de carbone à parois multiplesUn nanotube de carbone multifeuillet est constitué de plusieurs feuillets de graphènes enroulés les uns autour des autres. Il existe deux modèles pour décrire la structure des nanotubes multifeuillets :
- le modèle poupée russe: les plans de graphène sont arrangés en cylindres concentriques ;
- le modèle parchemin: un seul feuillet de graphène est enroulé sur lui-même, comme une feuille de papier.
Polycarbonates
Viscosité élongationnelleLa viscosité élongationnelle est la viscosité apparaissant lorsqu’une contrainte élongationnelle est appliquée au fluide. (Wikipedia)Index. décimale : 668.4 Plastiques, vinyles Résumé : A one-step ultrasonic film casting process to manufacture nanocomposite films was developed, in which polycarbonate (PC) was mixed with multi-walled carbon nanotubes (CNT) and cast into films in one process. Numerical and experimental investigations of necking phenomenon were carried out for film casting of PC/CNT composites. Experimental results revealed that the necking along film line decreased with imposition of ultrasound and increasing CNT content, indicating that incorporation of CNT and imposition of ultrasound restrained the elongational flow behavior of melt, resulting in film of a larger width. Isothermal and nonisothermal numerical simulations of the process were performed. In isothermal simulations, the polymer melt was assumed to be maintained at the die temperature. In nonisothermal simulations, the temperature change along the film line was determined from heat transfer calculations with the WLF temperature-dependent viscosity. The simulated and experimental results on normalized film width, defined as a ratio of cast film width to die width, as a function of the distance from the die at various extension ratios were compared. The comparison indicated that changes in film width and thickness along the stretching direction in the nonisothermal process were in better agreement with experimental results than that in the isothermal process. Both experimental and simulated results showed a decrease of film width with take-up speed. Due to the presence of edge effect, the film width in experiment was lower than the simulated one. With incorporation of CNT, a better agreement between experimental and simulated results was obtained, due to a reduced edge effect in the film. Note de contenu : - EXPERIMENTAL : Materials - Preparation of PC/CNT nanocomposite films - Testing
- RESULTS AND DISCUSSION : Processing characteristics - Necking phenomenon during film casting - Mechanical properties
- NUMERICAL SIMULATION OF THE FILM CASTING PROCESS : Isothermal simulation - Non-isothermal simulation
- Table 1 : Parameters used in film casting simulation
- Table 2 : Elongational viscosity of PC/CNT compositesDOI : https://doi.org/10.1515/ipp-2021-4200 En ligne : https://drive.google.com/file/d/1l5bi0RCPdWKDKFcbCnAXkY18HhEQ806J/view?usp=shari [...] Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37912
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Code-barres Cote Support Localisation Section Disponibilité 23739 - Périodique Bibliothèque principale Documentaires Disponible Effect of mixing conditions and polymer particle size on the properties of polypropylene/graphite nanoplatelets micromoldings / Renze Jiang in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
[article]
Titre : Effect of mixing conditions and polymer particle size on the properties of polypropylene/graphite nanoplatelets micromoldings Type de document : texte imprimé Auteurs : Renze Jiang, Auteur ; Piyush Lashkari, Auteur ; Shengtai Zhou, Auteur ; Andrew N. Hrymak, Auteur Année de publication : 2022 Article en page(s) : p. 372-382 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation
Composites à fibres -- Moulage par micro-injection
Composites à fibres de graphite
Conducteurs organiques
Microstructures
Nanoparticules
Polypropylène
ThermocinétiqueIndex. décimale : 668.4 Plastiques, vinyles Résumé : In this study, properties of polypropylene/graphite nanoplatelets (PP/GNP) composites and corresponding micromoldings were systematically studied in terms of filler loading concentrations and mixing methods. PP of different forms, i.e., PP pellets and powders, were adopted to fabricate PP/GNP composites. Additionally, a comparative study of precoating GNP and PP powders using solvent-based solution blending and ultrasonication-assisted mixing was performed. Results showed that PP/GNP composites prepared using powder form PP resulted in at least one order of magnitude higher electrical conductivity than using pellet form PP and further reduced the percolation threshold from 12.5 to 10 wt%, which was related to the state of filler distribution within corresponding moldings. Morphology observations revealed that microparts prepared with powder-PP/GNP composites exhibited less preferential alignment of GNP particles along the flow direction when compared with those molded using pellet-PP/GNP counterparts, which was helpful in improving the overall electrical conductivity for PP/GNP micromoldings. Note de contenu : - EXPERIMENTAL SECTION : Materials - Sample preparation
- CHARACTERIZATION : Electrical conductivity - Morphology - Differential scanning calorimetry
- RESULTS AND DISCUSSION : Electrical conductivity - Morphology - Differential scanning calorimetry
- Table 1 : Characteristic Data from DSC Scans for PP/GNP feeds (top row) and µIM microparts (bottom row). Cycle 1: 1st heating cycle. Cycle 2: cooling cycle. Cycle 3: 2nd heating cycleDOI : https://doi.org/10.1515/ipp-2022-0004 En ligne : https://drive.google.com/file/d/1qw8Ibyf-E7sqUi1vjl_V9cgnu7o1L3jN/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37913
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Code-barres Cote Support Localisation Section Disponibilité 23739 - Périodique Bibliothèque principale Documentaires Disponible Extrusion foaming of linear and branched polypropylenes - input of the thermomechanical analysis of pressure drop in the die / Carlos Sandino in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
[article]
Titre : Extrusion foaming of linear and branched polypropylenes - input of the thermomechanical analysis of pressure drop in the die Type de document : texte imprimé Auteurs : Carlos Sandino, Auteur ; Edith Peuvrel-Disdier, Auteur ; Jean-François Agassant, Auteur ; Patrice Laure, Auteur ; Séverine A. E. Boyer, Auteur ; Geoffrey Hibert, Auteur ; Yves Trolez, Auteur Année de publication : 2022 Article en page(s) : p. 383-395 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermomécanique
Caractérisation
Extrusion moussage
Mousses plastiques -- Extrusion
PolypropylèneIndex. décimale : 668.4 Plastiques, vinyles Résumé : This paper aims at a better understanding of the polypropylene (PP) physical extrusion foaming process with the objective of obtaining the lowest possible foam density. Two branched PPs were compared to the corresponding linear ones. Their shear and elongation viscosities were measured as well as their crystalline properties. Trials were conducted in a single screw extruder equipped with a gear pump and a static mixer cooler to adjust the melt temperature at the final die. The effect of decreasing this temperature on the PP foamability and on the pressure drop in the die was analyzed. The foam density of branched PPs varies from high to low values while decreasing the foaming temperature. In the same processing conditions, the foam density of linear PPs does not decrease so much, as already evidenced in the literature. The foamability transition coincides with an increase of the pressure drop in the die. The originality of the work lies in the thermomechanical analysis of the polymer flow in the die which allows the identification of the relevant physical phenomena for a good foamability. The comparison of the experimental pressure drops in the die and the computed ones with the identified purely viscous behavior points out the influence of the foaming temperature and of the PP structure. At high foaming temperature the discrepancy between experimental measurements and the computed pressure drops remains limited. It increases when decreasing the foaming temperature, but the mismatch is much more important for branched PPs than for linear ones. This difference is analyzed as a combination of the activation energy of the viscosity, the elongational viscosity in the convergent geometry of the die which is much more important for branched PPs than for linear ones, and the onset of crystallization which occurs at higher temperature for branched PPs than for linear PPs. Note de contenu : - CHARACTERIZATION OF THE LINEAR AND BRANCHED POLYPROPYLENES
- FOAMING PROCESSES
- EXPERIMENTAL SET UP : Processing conditions - Influence of the processing conditions on the foam density
- THERMOMECHANICAL ANALYSIS OF THE FOAMING PROCESSDOI : https://doi.org/10.1515/ipp-2022-0025 En ligne : https://drive.google.com/file/d/1c_FH7lX3s_oRI2pmxBYZ3tXm5W93fgYt/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37914
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Code-barres Cote Support Localisation Section Disponibilité 23739 - Périodique Bibliothèque principale Documentaires Disponible Improving the thickness distribution of parts with hybrid thermoforming / Fernando M. Duarte in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
[article]
Titre : Improving the thickness distribution of parts with hybrid thermoforming Type de document : texte imprimé Auteurs : Fernando M. Duarte, Auteur ; Catarina G. Ribeiro, Auteur ; João G. Ferreira, Auteur ; SÃlvia A. Forte, Auteur ; Jose A. Covas, Auteur Année de publication : 2022 Article en page(s) : p. 396-405 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Etat fondu (matériaux)
FilamentsFibre de longueur infinie ou extrême comme celle qu'on trouve dans la soie à l'état naturel. Les fibres manufacturées sont extrudées en filaments qui sont transformés en fils continus, en fibres courtes ou en câbles.
Lasers -- Applications industrielles
Matériaux -- Epaisseur
Matières plastiques -- Thermoformage
Usinage par laserIndex. décimale : 668.4 Plastiques, vinyles Résumé : With the aim of improving the thickness gradient of thermoformed parts, and thus increase their performance and/or reduce their weight, the concept of hybrid thermoforming is introduced, whereby local thickness differences in extruded sheets are created prior to thermoforming. Material is removed by CO2 ablation or 3D printing of an over-thickness at specific locations of sheets previously extruded. The feasibility and potential usefulness of the approach is explored experimentally for the production of a truncated conical cup, since this is a well-characterized application. The conventional thickness distributions obtained by conventional vacuum forming are significantly changed with the new strategy and can be tuned by adequately selecting the locations and amount of material do be removed and/or added. Note de contenu : The concept of hybrid thermoforming
Experimental
Results and discussion : Removing material approach - Adding material approachDOI : https://doi.org/10.1515/ipp-2022-4222 En ligne : https://drive.google.com/file/d/1_k1niD222mz_teTTN-MJkmmodAET_QPd/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37915
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Code-barres Cote Support Localisation Section Disponibilité 23739 - Périodique Bibliothèque principale Documentaires Disponible Synergistic material extrusion 3D-printing using core–shell filaments containing polycarbonate-based material with different glass transition temperatures and viscosities / Fang Peng in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
[article]
Titre : Synergistic material extrusion 3D-printing using core–shell filaments containing polycarbonate-based material with different glass transition temperatures and viscosities Type de document : texte imprimé Auteurs : Fang Peng, Auteur ; Bryan D. Vogt, Auteur ; Miko Cakmak, Auteur Année de publication : 2022 Article en page(s) : p. 406-414 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Etat fondu (matériaux)
FilamentsFibre de longueur infinie ou extrême comme celle qu'on trouve dans la soie à l'état naturel. Les fibres manufacturées sont extrudées en filaments qui sont transformés en fils continus, en fibres courtes ou en câbles.
Impression tridimensionnelle
Matières plastiques -- Extrusion
Matières plastiques -- Propriétés mécaniques
PolycarbonatesIndex. décimale : 668.4 Plastiques, vinyles Résumé : The application of 3D printing of thermoplastics by Material Extrusion (MatEx) has commonly been limited by their poor mechanical strength that results from voids and weak interfaces between printed layers. Here, we demonstrate that core–shell structured filaments made of polycarbonate-based thermoplastics can achieve synergistic improvement in their interfacial bonding from the combination of high-glass transition temperature (T g)/high-viscosity core and low-T g/low-viscosity shell. Tensile strength along the printing direction was enhanced with the core–shell filaments. Layer-interfacial bonding strength as determined by Izod impact tests of the 3D printed parts is significantly improved by using filaments either with only a core–shell T g mismatch or both T g/viscosity core–shell mismatch. The mechanical behavior can be rationalized in terms of improved inter-layer molecule diffusion by a low T g/viscosity shell, better printability at higher temperature due to the core with higher melt strength, and better bulk mechanical strength of high-viscosity/T g core. Note de contenu : - EXPERIMENTAL : Filament extrusion - 3D printing - Characterization
- RESULTS AND DISCUSSION : Material properties - Core-shell structure - Tensile properties
- Table 1 : Temperature profile for filament extrusion using Rheomex 252p.
- Table 2 : Temperature profile for filament extrusion using M-PAK125
- Table 3 : Temperature profile for filament co-ExtrusionDOI : https://doi.org/10.1515/ipp-2022-4217 En ligne : https://drive.google.com/file/d/1t-UNX1-sKaib9Np8EPRGlMqfrDgCAjXm/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37916
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Code-barres Cote Support Localisation Section Disponibilité 23739 - Périodique Bibliothèque principale Documentaires Disponible TPU-based porous heterostructures by combined techniques / Alessandra Longo in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
[article]
Titre : TPU-based porous heterostructures by combined techniques Type de document : texte imprimé Auteurs : Alessandra Longo, Auteur ; Deborah Giannetti, Auteur ; Daniele Tammaro, Auteur ; Salvatore Costanzo, Auteur ; Ernesto Di Maio, Auteur Année de publication : 2022 Article en page(s) : p. 415-426 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Calorimétrie
Caractérisation
Contraintes (mécanique)
Essais dynamiques
Hétérostructures
Impression tridimensionnelle
Masse volumique
Morphologie (matériaux)
Mousses plastiques
Polyuréthanes
Pression
Rhéologie
Température
ThermogravimétrieIndex. décimale : 668.4 Plastiques, vinyles Résumé : The production of thermoplastic polyurethane-based porous heterostructures combining physical foaming with fused deposition modeling is detailed in this contribution. The choice of combining these two techniques lies in the possibility of creating objects endowed with a dual-scale structure at millimeter scale by fused deposition modeling and at microscopic scale by gas foaming. Thermal stability and rheological properties of the neat polymer were studied prior to foaming to design a suitable processing protocol and three different combined techniques are proposed: pressure quench, temperature rise and direct 3D foam printing. Foam morphologies were evaluated by SEM and foamed samples were characterized by thermal and mechanical analyses to highlight the differences among the combined processing techniques. Samples foamed via pressure quench exhibit the highest degree of crystallinity and a uniform cell morphology, also resulting in the largest stiffness. The results presented in this contribution open up the possibility of producing objects with complex geometry and porosity architecture at the dual scale. Note de contenu : - MATERIALS AND METHODS : Materials - Samples preparation - Characterization - Processing methods
- RESULTS : Rheological properties - Thermogravimetry - Morphologies - Density - Differential scanning calorimetry - Compression tests
- Table 1 : Process parameters for the combined foaming processing methods
- Table 2 : Densities of the samples under investigationDOI : https://doi.org/10.1515/ipp-2022-0026 En ligne : https://drive.google.com/file/d/14SiaJ8Y0pDQKi9ya2fwj2sG5jKoQQ1Qx/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37917
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Code-barres Cote Support Localisation Section Disponibilité 23739 - Périodique Bibliothèque principale Documentaires Disponible Surfactant-free oil-in-oil emulsion-templating of polyimide aerogel foams / Erin Farrell in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
[article]
Titre : Surfactant-free oil-in-oil emulsion-templating of polyimide aerogel foams Type de document : texte imprimé Auteurs : Erin Farrell, Auteur ; Sadhan C. Jana, Auteur Année de publication : 2022 Article en page(s) : p. 427-441 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Aérogels
Caractérisation
Emulsions
Emulsions -- Stabilité
Gélification
Matériaux mésoporeux
Matériaux poreux
Modèles mathématiques
Mousse (chimie)
PolyimidesIndex. décimale : 668.4 Plastiques, vinyles Résumé : A surfactant-free oil-in-oil emulsion-templating method is presented for fabrication of monolithic polyimide aerogel foams using monomer systems that produce fast sol–gel transition. An aerogel foam is a high porosity (∼90%) material with coexisting meso- and macropores inherent to aerogels with externally introduced micrometer size open cells (macrovoids) that are reminiscent of foams. The macrovoids are introduced in polyimide sol using surfactant-free emulsion-templating of droplets of an immiscible liquid that are stabilized against coalescence by fast sol–gel transition. Three immiscible liquids – cyclohexane, n-heptane, and silicone oil – are considered in this work for surfactant-free emulsion-templating. The aerogel foam monoliths, recovered by supercritical drying, exhibit smaller size macrovoids when n-heptane and cyclohexane are used as emulsion-templating liquid, while the overall porosity and the bulk density show weak dependence on the emulsion-templating liquid. Note de contenu : - EXPERIMENTAL SECTION : Materials - Characterization
- RESULTS AND DISCUSSION : Emulsion stability - Gel times - Aerogel foam materials - BET surface area - Macrovoid and pore architecture
- Table 1 : Lists several properties of the solvents used.
- Table 2 : Interfacial tension values without surfactant
- Table 3 : Mean, median, maximum, and minimum droplet diameter in surfactant-free emulsions in N,N-dimethylformamide
- Table 4 : Droplet distribution data and mean diameter in micrometer in each size range
- Table 5 : Emulsion separation times and creaming rates in polyimide so
- Table 6 : Bulk density, shrinkage, porosity, and percent pores in macro- and mesopore range of emulsion-templated polyimide aerogel foams
- Table 7 : BET surface areaDOI : https://doi.org/10.1515/ipp-2022-4248 En ligne : https://drive.google.com/file/d/1_xRc5_bNKiT5U2NT_gxrCiSs-qCRpbw0/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37918
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Code-barres Cote Support Localisation Section Disponibilité 23739 - Périodique Bibliothèque principale Documentaires Disponible Factors determining the flow erosion/part deformation of film insert molded thermoplastic products / Demei Lee in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
[article]
Titre : Factors determining the flow erosion/part deformation of film insert molded thermoplastic products Type de document : texte imprimé Auteurs : Demei Lee, Auteur ; Yu-Kai Lin, Auteur ; Siang-Chen Hsu, Auteur ; Ya-Ling Tang, Auteur ; Shih-Jung Liu, Auteur Année de publication : 2022 Article en page(s) : p. 442-451 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse numérique
Déformations (mécanique)
Erosion par écoulement
Matières plastiques -- Moulage par insertion de film
Polyéthylène téréphtalate
Polystyrène
Simulation par ordinateurIndex. décimale : 668.4 Plastiques, vinyles Résumé : Flow erosion and part deformation are unsolved molding problems that restrict the overall success of film insert molding. This work investigated, both experimentally and numerically, the factors that affect flow erosion and part deformation in film inset molded products. Three plate-with-thickness-variation geometries, namely flat, thin-to-thick, and thick-to thin, were molded for the products. Polystyrene films and polyethylene terephthalate (PET) resins were employed in the experiments. It was found that the thin-to-thick specimens exhibited the most severe flow erosion. Increasing the injection pressure or melt temperature worsened flow erosion. Meanwhile, for the processing parameters adopted in the experiments, part deformation generally increased with melt temperature and hold time, while it decreased with injection pressure and hold pressure. Additionally, a numerical software (Moldex® 3-D) was employed to simulate the temperature and shear stress distributions in molded products. The calculated results suggested that part deformation in insert molded products results mainly from the non-uniform temperature profile during the cooling stage, owing to the product configuration and the insert film, while flow erosion is induced by the high shear stress of the polymer melt in the filling stage. Note de contenu : - Experimental procedure
- Numerical calculation
- Results and discussion : Influence of processing parameters on flow erosion - Effects of processing variables on molded part deformation
- Table 1 : The processing variables, as well as the values used in the experimentsEn ligne : https://drive.google.com/file/d/1OanuEjBV6fxzkXp4Yv1obDO1veeEeDQE/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37919
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Code-barres Cote Support Localisation Section Disponibilité 23739 - Périodique Bibliothèque principale Documentaires Disponible The extrusion of EPDM using an external gear pump : experiments and simulations / Vincent G. de Bie in INTERNATIONAL POLYMER PROCESSING, Vol. 37, N° 4 (2022)
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Titre : The extrusion of EPDM using an external gear pump : experiments and simulations Type de document : texte imprimé Auteurs : Vincent G. de Bie, Auteur ; Michelle M .A. Spanjaard, Auteur ; Martien A. Hulsen, Auteur ; Patrick D. Anderson, Auteur Année de publication : 2022 Article en page(s) : p. 452-468 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caoutchouc
Caractérisation
Eléments finis, Méthode des
Ethylène-propylène-diène monomère
Matières plastiques -- Extrusion
Pompes à engrenagesIndex. décimale : 668.4 Plastiques, vinyles Résumé : External gear pumps are used in fluid transport systems because of their tight clearances and accurate flow control. These tight clearances are a challenge for numerical studies in terms of spatial discretization. In earlier work, the flow of a viscous fluid in an external gear pump is computed using the finite element method (FEM). An element size based on the respective distance between boundaries is proposed. In this study, results based on the earlier work are compared to extrusion experiments of EPDM. The aim of this study is not only to validate the numerical simulations, but also to determine what material characteristics need to be taken into account for an accurate output prediction of the external gear pump. Especially the introduction of shear-thinning behavior results in an improvement of the amplitude of the pressure difference fluctuation. Taking into account compressibility, alters the torque fluctuation in such a way that it mimics the experiments. Unfortunately, the fluctuation in torque still has a too high amplitude. Eventually, simulations are performed including shear-thinning behavior, a temperature- and pressure-dependent viscosity, and compressibility. The effect of measuring the material behavior using oscillatory or shear experiments is shown. Furthermore, the simulations are applied to a second EPDM. Finally, different processing conditions are tested. For the simulations, only qualitative agreement is found, possibly as a result of the no slip boundary condition. Note de contenu : - PROBLEM DEFINITION AND GOVERNING EQUATIONS : Governing equations - Initial and boundary conditions - Weak form - Discretization
- EXPERIMENTS : Materials - Characterization - Extrusion system
- RESULTS : Characterization - Extrusion - Material behavior
- Table 1 : The measurements performed using the extrusion system
- Table 2 : The parameters for the Carreau-Yasuda model and the WLF equationDOI : https://doi.org/10.1515/ipp-2022-4240 En ligne : https://drive.google.com/file/d/1breXzICPmTeqWMnreAMbSM7O6cJuD5fa/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37920
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