Analysis of self-reinforced mechanism of over-molding polypropylene parts / Y. Lu in INTERNATIONAL POLYMER PROCESSING, Vol. XXXV, N° 1 (03/2020)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXV, N° 1 (03/2020) . - p. 95-106 Titre : Analysis of self-reinforced mechanism of over-molding polypropylene parts Type de document : texte imprimé Auteurs : Y. Lu, Auteur ; K.-Y. Jiang, Auteur ; M.-J. Wang, Auteur ; Y. Zhang, Auteur ; Y.-Y. Liu, Auteur Année de publication : 2020 Article en page(s) : p. 95-106 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermique Calorimétrie Composites thermoplastiques auto-renforcés Essais dynamiques Matières plastiques -- Moulage par micro-injection Matières plastiques -- Propriétés mécaniques Matières plastiques -- Surmoulage Microscopie Morphologie (matériaux) Polypropylène Structure cristalline (solide) Traction (mécanique) Index. décimale : 668.4 Plastiques, vinyles Résumé : On the premise that the overall structure and composition of the parts remain unchanged, the over-molding of self-reinforced polymer composites parts (OM-SRCs parts) prepared in this paper change the aggregation structure of the parts by combining multi-component sequential molding technology with micro-injection molding technology. Thus, it improves the comprehensive performance of the parts, and achieves the purpose of self-reinforcing. The morphological feature of self-reinforced parts during over-molding are obviously different from those formed by conventional injection molding, which also leads to differences in physical properties. In this study, two types of polypropylene parts of the same size (60 × 12 × 2 mm3) were prepared, and their micro-morphologies comparison were investigated by means of polarized light microscopy (PLM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). From the results, it was found that the tensile properties of OM-SRCs parts were improved by up to 9.46% compared with the conventional parts. Through PLM observation, it is found that the section shape of OM-SRCs parts perpendicular to the flow direction shows a double “skin-core” structure, resulting in the increase of the area ratio of skin layer to 24% (16% in conventional parts). SEM was carried out on the skin layer near the fusion position of the interface, and a highly oriented “shish-kebab” structure was observed. Through DSC and 1D-WAXD pattern analysis, it was found that the overall crystallinity of OM-SRCs parts decreased by 8.53% and 5.32% compared with the conventional parts, respectively. The 2D-WAXD pattern analysis showed that the molecular orientation degree of the skin layer of OM-SRCs parts increased by 15.65%. By means of the response surface method, the molecular orientation obtained was the decisive factor affecting the performance of OM-SRCs parts. By means of the least squares' minimization procedure, a dimensionless equation between the micro-morphologies and mechanical properties was established, which makes the “adjustability” of the sample performance be preliminarily realized. Note de contenu : - EXPERIMENTAL : Sample material - Sample size - Sample preparation - Tensile test - Polarized light microscopy (PLM) - Scanning electronic microscopy - Differential scanning calorimetry - Wide-angle x-ray diffraction analysis (WAXD) - RESULTS AND DISCUSSION : Mechanical properties - Microscopic observation - Polycrystalline composition and crystallinity - Crystalline molecular orientation - Morphology-mechanical properties relationship DOI : https://doi.org/10.3139/217.3872 En ligne : https://drive.google.com/file/d/14hDR4r6sRbCkxUGsInR-Y-6Dv0l2BiuQ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33782 [article]

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Influence of scale effect on filling behavior of injection molding by visualization method / K.-Y. Jiang in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 1 (03/2012)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVII, N° 1 (03/2012) . - p.28-30 Titre : Influence of scale effect on filling behavior of injection molding by visualization method Type de document : texte imprimé Auteurs : K.-Y. Jiang, Auteur ; J.-N. Tian, Auteur ; M.-J. Wang, Auteur ; J.-J. Ma, Auteur ; Z.-K. Yu, Auteur Année de publication : 2012 Article en page(s) : p.28-30 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Matières plastiques -- Moulage par injection Tags : 'Moulage  injection'  'Méthode  visualisation'  'Comportement  dynamique  remplissage'  multi-cavité'  'Effet  échelle'  'Déséquilibre  'Etude  expérimentale' Index. décimale : 668.9 Polymères Résumé : For better understanding of thin-wall injection molding processes, a visualization injection mold and high speed camera were used to observe the dynamic filling behavior of melt in cavities with different thicknesses during the injection molding process. The impact of the scale effect on the melt-filling rate and filling imbalance in the multi-cavity were also studied. Results indicated that the filling behavior of the melt during the multi-cavity molding process was related to the cavity thickness. The experiment results can be used to describe the filling imbalance phenomenon during the injection molding process and to provide experimental evidence for precise injection molding technology at the micro scale. DOI : 10.3139/217.2497 En ligne : https://drive.google.com/file/d/1KHgtmj1NTnevIq6ey5Jdah-v3TxUHMj8/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13718 [article]

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Polymer flow behavior analysis based on physical visualization technologo for ultrasonic vibration-assisted injection molding / K.-Y. Jiang in INTERNATIONAL POLYMER PROCESSING, Vol. XXXII, N° 3 (07/2017)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXII, N° 3 (07/2017) . - p. 290-297 Titre : Polymer flow behavior analysis based on physical visualization technologo for ultrasonic vibration-assisted injection molding Type de document : texte imprimé Auteurs : K.-Y. Jiang, Auteur ; Z. Ji, Auteur ; H. Li, Auteur ; M.-J. Wang, Auteur ; T.-M. Yu, Auteur Année de publication : 2017 Article en page(s) : p. 290-297 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Matières plastiques -- Moulage par injection assisté par ultrasons Polypropylène Rhéologie Index. décimale : 668.4 Plastiques, vinyles Résumé : To understand the flow behavior of a melted polymer during injection molding with ultrasonic vibration, a new visualization device was developed and a method was proposed to analyze the filling velocity field during the injection molding process. Using the device and method, both the influence of ultrasonic vibration on the velocity of the filling front and the velocity distribution of a polypropylene melt within a cavity are discussed. The results showed that the filling front velocity of the melt was improved by ultrasonic vibration (the filling front velocity was improved by up to 27% when 200 W of ultrasonic power was applied). In addition, it was shown that the velocity gradient of the melt within the cavity decreased, and that the velocity distribution became more uniform during ultrasonic vibration. Note de contenu : - EXPERIMENTAL : Materials - Experimental facility - Experimental parameters - RESULTS AND DISCUSSION : Analyzing methods - Melt front flow behavior - Melt flow behavior in a cavity DOI : 10.3139/217.3183 En ligne : https://drive.google.com/file/d/1P57EOCT6NhREbV3YJszHcpfbdtcdEm-V/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=28829 [article]

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