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Auteur H. Hamada |
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Ajouter le résultat dans votre panier Affiner la rechercheEffect of pre-molding process and additive of injection molded wood/PP composites / Y. Yu in INTERNATIONAL POLYMER PROCESSING, Vol. XXIX, N° 4 (08/2014)
Titre : Effect of pre-molding process and additive of injection molded wood/PP composites Type de document : texte imprimé Auteurs : Y. Yu, Auteur ; Q. Y. Yang, Auteur ; M. Nomura, Auteur ; H. Hamada, Auteur Année de publication : 2014 Article en page(s) : p. 440-446 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bois
Composites à fibres -- Additifs
Composites à fibres végétales -- Moulage par injection
Composites à fibres végétales -- Propriétés mécaniques
Flexion trois points
Impact (mécanique)
Morphologie (matériaux)
Polyalphaoléfine
Polypropylène
Poudres
Traction (mécanique)Index. décimale : 668.4 Plastiques, vinyles Résumé : Injection molded composites are becoming more widespread in recent years because of their high quality and low cost. However, compared to synthetic fiber composites, it is difficult to maintain a constant fiber volume fraction and uniform distribution for natural fiber composites during the direct injection process. This is mainly because natural fibers are more easily twisted during feeding into the injection machine, owing to their rough surfaces. These feeding difficulties are particularly due to the low bulk densities of natural fibers, especially natural fillers. Additional challenges to the injection process include the concentration and, especially for natural filler reinforced composite. To address these problems, the current study investigates the mechanical properties and morphologies of polypropylene (PP) reinforced by wood powder. Two pre-molding processes, dry-blending and compounding, were compared, and the effects of an additive (crystalline polyalpha olefin (CPAO)) on the mechanical properties of the wood/PP composites were investigated. This investigation is based on tensile, three point bending, and Izod impact tests, and scanning electron microscope (SEM) observation of the fracture surfaces. Results indicated that the composites molded through compounding exhibited better mechanical properties than the samples molded through the direct dry-blending process. In addition, the tensile and bending properties of the composites produced through compounding were found to increase with the addition of CPAO content, because of improved wood powder distribution in the PP matrix. Note de contenu : - EXPERIMENTAL : Materials - Dry-blending and compounding - Injection molding - Tensile test - Three point bending test - Izod impact test - Etching process - Scanning electron microscopy (SEM)
- EXPERIMENTAL RESULTS AND DISCUSSION : Particle size distribution of wood powder - Effect of pre-molding process (dry-blending and compounding) - Effect of CPAO contentDOI : 10.3139/217.2826 En ligne : https://drive.google.com/file/d/1P3Hu1gTgnzQJFtF2RLYJWGwP7EzDsJci/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21822
in INTERNATIONAL POLYMER PROCESSING > Vol. XXIX, N° 4 (08/2014) . - p. 440-446[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 16454 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Flow behavior of sandwich injection molding in sequential and simultaneous injection Type de document : texte imprimé Auteurs : D. Watanabe, Auteur ; U. S. Ishiaku, Auteur ; T. Nagaoka ; K. Tomari ; H. Hamada Année de publication : 2003 Article en page(s) : p. 199-203 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The flow behavior of skin and core materials in co-injection molding was investigated to understand the flow patterns that could lead to core breakthrough in sequential and simultaneous injection molding. A spiral-flow mold was used and the core material was loaded with a black master batch to facilitate the monitoring of the core material. PC/ABS blend was used as the skin material and ABS was the core material. It was revealed irrespective of simultaneous injection time, sandwich injection molding display the four flow regions identified earlier i.e. primary injection region, core advance region, core expansion region and core breakthrough region. The flow length of core expansion region lengthened with increasing simultaneous injection time of skin and core material while the overall injection time decreased. It was also observed that the core became thinner and wider with increasing simultaneous injection time. DOI : 10.3139/217.1735 En ligne : https://drive.google.com/file/d/1OoPgF6TJiC5lDOU-6BjdZ_P3Ie_I5GCt/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3312
in INTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 2 (06/2003) . - p. 199-203[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001024 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Interfacial characteristics of film insert moldings consisting of semicrystalline and amorphous polymers Type de document : texte imprimé Auteurs : Y. W. Leong, Auteur ; H. Hamada, Auteur Année de publication : 2008 Article en page(s) : p. 183-191 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Film insert moldings were produced from amorphous and crystalline polymers, i.e. PC+ABS and PET respectively. The vastly different characteristics of these polymers provide an interesting platform to study the mechanisms that are responsible for interfacial bond formation, particularly when these materials were molded at different molding conditions. It was observed that intermolecular diffusion between amorphous polymers takes place at virtually any temperature as long as it is kept above the glass transition temperature of the material, though higher temperatures are favorable to accelerate diffusion. As for crystalline polymers, there is an initial need to create free and mobile molecular chains by heating the materials to its melting temperature before any significant diffusion takes place. Certain criteria have to be met, irrespective of the materials used, before good interfacial bonding is achieved. Firstly, the injection molding parameters should be optimized to ensure intimacy between the surfaces of the film and injected resin. Once this is achieved, interdiffusion of molecules should be promoted to ensure extensive film-substrate molecular entanglements. The state of molecular entanglement should then be retained for a sufficient amount of time as the material solidifies in order to obtain good film-substrate adhesion. DOI : 10.3139/217.2038 En ligne : https://drive.google.com/file/d/1H4hd2-l3A-zkV-8k9jmQCJOR_rDborNj/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2647
in INTERNATIONAL POLYMER PROCESSING > Vol. XXIII, N° 2 (05/2008) . - p. 183-191[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 010098 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Material behavior in the plasticizing cylinder of an injection molding of the vent type Type de document : texte imprimé Auteurs : Y. Hisakura, Auteur ; I. Hisamitsu, Auteur ; M. Sugihara, Auteur ; S.-I. Tanifuji, Auteur ; H. Hamada, Auteur Année de publication : 2018 Article en page(s) : p. 652-661 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse des flux de matières et d'énergie
Matières plastiques -- Moulage par injection
Plastification
Rhéologie
Simulation par ordinateur
Terpolymère acrylonitrile butadiène styrèneIndex. décimale : 668.4 Plastiques, vinyles Résumé : Thermoplastic injection molding is applied in a wide variety of products. It is known that volatile components generated when resin melts cause structural defects during the thermoplastic injection process. Not only that, the pre-injection preparation work including drying the material and maintaining the metal mold, have become standard procedures to prevent these defects, but these procedures deteriorate productivity. Vent-type injection molding involves the use of cylinders featuring a vent hole at the center of the plasticizing cylinder. Although it is a conventional molding method, there are many issues including resin leakage from a vent hole and difficulty of material replacements. These issues prevented it from widespread application. Moreover, the vent-type plasticization process has not been examined theoretically or systematically. In order to maximize and generalize functions of vent-type molding, it is necessary to clarify the flow behavior of resin in the vent cylinder. In this study, we verified the flow behavior of resin in the vent-type plasticization cylinder through experimentation and simulation. In the simulation, using the flow analysis method, the filling rate inside the screw was determined by the pressure distribution inside the screw. In the experiments, the molding condition that causes venting up was verified by changing the screw rotation rates and the supply amount of the resin, for determining the filling rate of resin inside the screw. The filling rates obtained through the simulation and the experiment are almost the same. The result suggests that this simulation is very effective for predicting the filling rate. Note de contenu : - THEORY
- EXPERIMENTAL : Materials - Sample preparation
- RESULTS AND DISCUSSION : Results of vent-up testing - Comparative analysis of test resultsDOI : 10.3139/217.3572 En ligne : https://www.degruyter.com/document/doi/10.3139/217.3572/pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31404
in INTERNATIONAL POLYMER PROCESSING > Vol. XXXIII, N° 5 (11/2018) . - p. 652-661[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 20352 - Périodique Bibliothèque principale Documentaires Disponible
Titre : The flow behavior of core material and breakthrough phenomenon in sandwich injection molding : Part 1 : Dependence on viscosity and injection speed of skin/core materials Type de document : texte imprimé Auteurs : D. Watanabe, Auteur ; U. S. Ishiaku, Auteur ; T. Nagoaka ; K. Tomari, Auteur ; H. Hamada, Auteur Année de publication : 2003 Article en page(s) : p. 398-404 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Molding - The processing variables that control the occurrence of break-through phenomenon in sandwich injection molding were investigated. Particular attention was paid to the conditions that would yield an optimum sandwich molded part. The effects of variation of core volume ratio that would yield optimum core shot size, injection speed and the skin/core viscosity ratio were examined. The flow morphology at the various stages of flow was also explored. The study was conducted with a bar-flow mold mounted on a twin-barrel injection machine fitted with a common nozzle. It was noted that the core material flow distance depends on the core cylinder screw metering position (core shot size). At the stage at which the core material completely penetrated through the skin material (breakthrough), four distinct regions of flow could be identified. The flow distance of the core material is controlled by the injection speed of the core material while the injection speed of the skin material is of little significance. In order to increase the flow distance of the core material, it is effective to increase the core material injection speed albeit limited by an optimum value of screw metering position. It was found that the flow distance of the core material was longer when the core material viscosity was lower than that of the skin material but breakthrough occurred much earlier so core volume is limited. Breakthrough failed to occur when the viscosity of the core material was higher than that of the skin material. It was found that optimum core volume and core distribution occurred when skin/core viscosities were intermediate. The morphology of the skin material leading to breakthrough was also analyzed. Note de contenu : - EXPERIMENTAL : Materials - Sample preparation - Measurement of flow distance and break point - Morphology observation of PC/ABS alloy
- RESULTS : Effect of core volume ratio - Injection speed of skin-core - Effect of viscosity ratio of skin/core - Breakthrough - MorphologyDOI : 10.3139/217.17522 En ligne : https://drive.google.com/file/d/1GHXW7JVYwTFLIEvFSRqAUdR0_f4J4adN/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15824
in INTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 4 (12/2003) . - p. 398-404[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001026 - Périodique Bibliothèque principale Documentaires Disponible
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