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Nucleation of polypropylene homo- and copolymers / Markus Gahleitner in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 2-20 Titre : Nucleation of polypropylene homo- and copolymers Type de document : texte imprimé Auteurs : Markus Gahleitner, Auteur ; C. Grein, Auteur ; S. Kheirandish, Auteur ; J. Wolfschwenger, Auteur Année de publication : 2011 Article en page(s) : p. 2-20 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Copolymères Homopolymères Nanoparticules Nucléation Polymères en émulsion Polymères isotactiques Polypropylène Index. décimale : 668.9 Polymères Résumé : The combination of moderately slow crystal growth at large undercoolings together with the practical absence of sporadic nucleation makes isotactic polypropylene (iPP) an ideal material for controlled nucleation. In this review the different types of nucleating agents – inorganic and organic, particulate and soluble – for the different crystal modifications of iPP (α, β andγ) are presented together with their working mechanism and criteria for activity. The interaction between polymer type, nucleating agent and processing conditions in determining mechanical and optical properties conclude the survey. DOI : 10.3139/217.2411 En ligne : https://drive.google.com/file/d/1jgYSDoQg_eFq53uwTVrg2_LwBBADCp_e/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10978 [article]

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Fast prediction of injection pressure and minimal front temperature for injection moulding / P. Zhao in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 21-29 Titre : Fast prediction of injection pressure and minimal front temperature for injection moulding Type de document : texte imprimé Auteurs : P. Zhao, Auteur ; J. Fu, Auteur ; H. Zhou, Auteur ; B. Yan, Auteur Année de publication : 2011 Article en page(s) : p. 21-29 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse de bandes rapide Différences finies, Méthode des En analyse numérique, la méthode des différences finies est une technique courante de recherche de solutions approchées d'équations aux dérivées partielles qui consiste à résoudre un système de relations (schéma numérique) liant les valeurs des fonctions inconnues en certains points suffisamment proches les uns des autres. Cette méthode apparaît comme étant la plus simple à mettre en Å“uvre car elle procède en deux étapes : d'une part la discrétisation par différences finies des opérateurs de dérivation/différentiation, d'autre part la convergence du schéma numérique ainsi obtenu lorsque la distance entre les points diminue. Graphes, Théorie des Matières plastiques -- Moulage par injection Index. décimale : 668.9 Polymères Résumé : Fast prediction of injection pressure and minimal front temperature can usually be used to optimize the process parameters for injection moulding. In this paper, a fast strip analysis (FSA) model was presented on the basis of a geometric approximation method, which simplifies an original part to a rectangular edge-gated strip. The dimensions of the rectangular strip were calculated through the original part’s geometric mesh by using graph theory. Subsequently, a finite difference method was employed to simulate a non-isothermal and unidirectional flow in the strip. Numerical examples show that although FSA model is an approximation method, its results are approximately identical to that of detailed CAE software, while the running time of the proposed model is several magnitudes less than that of CAE software. DOI : 10.3139/217.2343 En ligne : https://drive.google.com/file/d/1_d0vx-kjcoQSJfSAAnhNWjhXpifzHuqf/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10979 [article]

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Study on melt spinning of shaped hollow polypropylene fibers / C. Prahsarn in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p.30-39 Titre : Study on melt spinning of shaped hollow polypropylene fibers Type de document : texte imprimé Auteurs : C. Prahsarn, Auteur ; N. Roungpaisan, Auteur ; W. Klinsukhon, Auteur ; N. Srisawat, Auteur Année de publication : 2011 Article en page(s) : p.30-39 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Extrusion filage Fibres creuses Fibres textiles synthétiques Polypropylène Viscosité Index. décimale : 668.9 Polymères Résumé : Influences of polymer and processing parameters on melt spinning, features, and structures of circular and triangular shaped hollow fibers were investigated. Spinnability of triangular hollow fibers was found to be more sensitive to polymer viscosity and processing conditions than that of circular hollow counterparts such that fiber breakage occurred when polypropylene with high viscosity was employed. Relatively low temperature due to high cooling at tip of triangular shape may cause stress concentration developed in spin-line, and lead to fiber breakage. Increasing temperature enabled continuous spinning in triangular hollow fibers. The obtained triangular hollow fibers possessed slightly larger diameters but smaller percent hole areas, compared to the circular ones. Results showed that diameters and percent hole areas of both circular and triangular hollow fibers tended to decrease with increasing spinning temperature and take up velocity, but tended to increase with increasing throughput rate. From WAXD results, crystalline orientation in hollow fibers was found affected by take up velocity, and slightly by fiber configuration. DOI : 10.3139/217.2363 En ligne : https://drive.google.com/file/d/1NnsbfigWU2tOsk6KTNtoVp08BJBNdHtS/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10980 [article]

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Lower temperature plasticizing and extrusion of polymer in spherical screw extruder under vibration force field / G. Zheng in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 40-47 Titre : Lower temperature plasticizing and extrusion of polymer in spherical screw extruder under vibration force field Type de document : texte imprimé Auteurs : G. Zheng, Auteur ; C. Xu, Auteur ; Y. Liu, Auteur ; J. Qu, Auteur ; T. Jiang, Auteur Année de publication : 2011 Article en page(s) : p. 40-47 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Énergie -- Consommation Matières plastiques -- Extrusion Matières plastiques -- Moulage Ondes électromagnétiques Plastification Polyéthylène haute densité Vis d'extrusion simple Index. décimale : 668.9 Polymères Résumé : Physical and mathematical model for polymer plasticizing in proposed electromagnetic dynamic spherical screw extruder were developed to explore polymer plasticizing and molding mechanism at lower temperature under vibration force field. Polymer plasticizing mechanism was studied by deriving the mathematical expressions of energy consumed and the polymer flow. The energy consumed in polymer plasticizing was depicted in terms of vibrating dissipation, polymer deformation, shear and friction energy. LDPE was used as an objective material and extruded by the extruder with the electromagnetic excitation and spherical screw. The experimental results show the good agreement with theoretical calculations. Both of them show that: Polymer processing temperature and energy consumption decrease significantly while the plasticizing rate is increased over 60% by introducing the vibration force field. The research offers experimental and theoretical references as well as the evaluation method for optimizing the polymer processing parameters and designing the vibration induced equipment. DOI : 10.3139/217.2372 En ligne : https://drive.google.com/file/d/1VYVOi19pybPDfjlHp7Qw6UPbCB6QCwtE/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10981 [article]

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Elastomer nanocomposites based on NR/EPDM/organoclay : morphology and properties / A. Alipour in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 48-55 Titre : Elastomer nanocomposites based on NR/EPDM/organoclay : morphology and properties Type de document : texte imprimé Auteurs : A. Alipour, Auteur ; Ghasem Naderi, Auteur ; G. R. Bakhshandeh, Auteur ; H. Vali, Auteur ; S. Shokoohi, Auteur Année de publication : 2011 Article en page(s) : p. 48-55 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Alliages polymères -- propriétés mécaniques Caoutchouc Diffractométrie de rayons X Ethylène-propylène-diène monomère Matériaux hybrides Microscopie électronique en transmission Montmorillonite Nanoparticules Rhéologie Silicates Index. décimale : 668.9 Polymères Résumé : Natural rubber/Ethylene Propylene Diene Monomer (NR/EPDM) blends of five different compositions (0/100), (25/75), (50/50), (75/25) and (100/0) with 1, 3, 5 and 7 phr organo-modified nanoclay (Cloisite 15A) were prepared by two-roll mill. The effect of organo-modified layered nanosilicates and composition on the cure characteristics, microstructure, mechanical, and rheological properties of the nanocomposites were studied. Results suggested the intercalation of polymer chains into the silicate layers which was evidenced by d-spacing results of X-ray diffraction patterns. TEM micrographs also directly confirmed XRD results. Mechanical properties of the nanocomposites depicted a nearly 40% percents increase respectively in the tensile modulus of 75NR/25EPDM containing 7 wt.% nanoclay. DOI : 10.3139/217.2381 En ligne : https://drive.google.com/file/d/1XwfY-AUYicC6qKRMSjM60AEWtDdMlj8u/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11037 [article]

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Rheological properties of neat and calcium carbonate particles filled polypropylene blends under axial vibration force field / Y. Liu in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 56-62 Titre : Rheological properties of neat and calcium carbonate particles filled polypropylene blends under axial vibration force field Type de document : texte imprimé Auteurs : Y. Liu, Auteur ; T. Jiang, Auteur ; G. Zeng, Auteur ; Y. Huang, Auteur ; X. Li, Auteur Année de publication : 2011 Article en page(s) : p. 56-62 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Carbonate de calcium Le carbonate de calcium (CaCO3) est composé d'un ion carbonate (CO32-) et d'un ion calcium (Ca2+), sa masse molaire est de 100,1 g/mole. C'est le composant principal du calcaire et de la craie, mais également du marbre. C'est aussi le principal constituant des coquilles d'animaux marins, du corail et des escargots. Ecoulement cisaillé Polypropylène Rhéologie Rhéomètres Viscosité Index. décimale : 668.9 Polymères Résumé : Structures, working mechanism, data collecting and processing methods of the self-made multifunctional all-electronic rheometer for polymer composites were introduced in detail. The validity of this equipment was proved by deriving the apparent shear viscosity expression under axial vibration condition and comparing the results obtained from both this selfmade rheometer and Rosand Rh7D capillary rheometer at steady state. With this equipment, the effects of calcium carbonate weight fraction, particle size and vibration parameters on apparent shear viscosity of calcium carbonate filled propylene composites were investigated. The results show that: the apparent shear viscosity of the composites increases with the filled particle concentration. However, it is seldom affected by particle size within certain a range of shear rate. While the apparent shear viscosity increases with the decrease of particle size at moderate shear rate. Besides, the apparent shear viscosity declines rapidly with the increasing vibration amplitude. However it exhibits a cosinoidal or sinusoidal trend as vibration frequency increases and peaks at the resonant frequency of the composites. DOI : 10.3139/217.2392 En ligne : https://drive.google.com/file/d/1uRl0Mo44JXinlpMQUvwhiY8RIdKQcH75/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11043 [article]

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Feasibility analysis of an in-mold multivariate sensor / David O. Kazmer in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 63-72 Titre : Feasibility analysis of an in-mold multivariate sensor Type de document : texte imprimé Auteurs : David O. Kazmer, Auteur ; S. P. Johnston, Auteur ; R. X. Gao, Auteur ; Z. Fan, Auteur Année de publication : 2011 Article en page(s) : p. 63-72 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Ecoulement visqueux Etat fondu (matériaux) Matières plastiques -- Moulage par injection -- Appareils et matériel Viscosimétrie Viscosité Index. décimale : 668.9 Polymères Résumé : The initial design of a novel multivariate sensor is described for the measurement of melt temperature, melt pressure, melt velocity, melt viscosity, and mold temperature. Melt pressure and temperature are respectively obtained through the incorporation of a piezoceramic element and infrared photodetector within the sensor head. Melt velocity is derived from the initial response of the melt temperature as the polymer melt flows across the sensor’s lens. The apparent melt viscosity is then derived from the melt velocity and the time derivative of the increasing melt pressure given the cavity thickness. The feasibility of the envisioned sensor is then analyzed using a productiongrade mold that is instrumented with commercial piezoelectric pressure sensors, infrared pyrometer, and thermocouples. Several predictive models of part weight are developed using multiple regression of data obtained from a design of experiments to evaluate the capability of the envisioned multivariate sensor. The results indicate a correlation coefficient, R2, of 0.79 for a model based on the machine settings, 0.80 for a model based on a cavity pressure sensor, 0.90 for a model based on the multivariate sensor, and 0.98 for a non-linear model based on the multivariate sensor. The implication is that multiple orthogonal sensing streams with high fidelity models are necessary to provide automatic quality assurance sufficient for fully automated plastics manufacturing. DOI : 10.3139/217.2397 En ligne : https://drive.google.com/file/d/16dwJo-zYo3LAZYHRIa7XGC50TQp5P_jX/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11044 [article]

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Experimental study on the filling of nano structures with infrared mold surface heating / H.-Y. Lin in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 73-81 Titre : Experimental study on the filling of nano structures with infrared mold surface heating Type de document : texte imprimé Auteurs : H.-Y. Lin, Auteur ; C.-H. Chang, Auteur ; W.-B. Young, Auteur Année de publication : 2011 Article en page(s) : p. 73-81 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Matières plastiques -- Moulage par injection Moules d'injection Nanostructures Polymères -- Effets de la température Rayonnement infrarouge Index. décimale : 668.9 Polymères Résumé : In the fabrication of plastic components with micro or nano structures, injection molding is one of the simple and most cost-effective processes. In the injection molding process, a complete filling of the micro or nano structures is necessary to fabricate a successful product. However, it is difficult to fully fill nano structures with an aspect ratio close to one or higher by the conventional molding process. In this study, mold inserts with nano channels were constructed by a LIGA-like process. The effects of the processing parameters and infrared heating on the filling of the nano structures were explored experimentally. Increasing the mold temperature, pressure, or filling rate did not improve the filling distance in nano channels with the conventional molding process significantly. Thus, an infrared mold surface heating system was introduced to assist the molding of the nano structures. To enhance the heating efficiency and reduce the cycle time, a heat-resistant layer was inserted under the mold cavity. The heat resistant plate led the heating system to work more efficiently. It easily increased the surface temperature over the glass transition temperature of plastic, thus fully filling the nano structures. DOI : 10.3139/217.2399 En ligne : https://drive.google.com/file/d/1k5ev8gqd4JNHLD74Y6PNYP9Qzcd75im6/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11052 [article]

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Effect of random and block copolypropylenes on structure and properties of uniaxially and biaxially oriented PP films / S. H. Tabatabaei in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 82-90 Titre : Effect of random and block copolypropylenes on structure and properties of uniaxially and biaxially oriented PP films Type de document : texte imprimé Auteurs : S. H. Tabatabaei, Auteur ; Abdellah Ajji, Auteur ; H. Ghasemi, Auteur Année de publication : 2011 Article en page(s) : p. 82-90 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermique Copolymères séquencés Films plastiques -- Propriétés mécaniques Microscopie en lumière polarisée Polypropylène Rhéologie Index. décimale : 668.9 Polymères Résumé : Cast films of two linear polypropylenes (PP) having different molecular weights and their blends with 5, 20, and 40 wt.% random and block copolymers were prepared. The produced cast films were uniaxially and biaxially hot drawn at T = 155ºC using a biaxial stretcher and the changes in structure and morphology were examined and related to barrier, mechanical, haze, and tear properties. The crystallinity and crystal size distribution of the films were studied using differential scanning calorimetry (DSC). The uniaxial drawing generated a highly oriented fibrillar structure, resulting in an increase in the melting point of the films. A significant effect of the random copolymer on the size of crystallites was found using DSC, which was also confirmed from polarized optical microscopy (POM). Compared to the neat homopolymers, finer and numerous spherulites were observed for the blends. During drawing, the applied loads in the machine and transverse directions (MD and TD, respectively) were recorded and related to breaking up and tilting of the crystal lamellae. Adding the random copolymer appreciably decreased the haze of the films and hence drastically improved the clarity. Tensile properties and tear resistance of the cast films in MD and TD were evaluated. The addition of the random copolymer slightly reduced the Young modulus and tensile strength, but increased the elongation at break. A slight increase in the oxygen transmission rate (OTR) of the biaxially drawn films were observed by adding the copolymer. DOI : 10.3139/217.2404 En ligne : https://drive.google.com/file/d/1Wu4KRz4nPjaAKjV4g9qq6NTTQtVcnsce/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11053 [article]

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Co-intercalation in PP clay nanocomposites : effect of short chain additives on rheological properties / B. Haworth in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 91-99 Titre : Co-intercalation in PP clay nanocomposites : effect of short chain additives on rheological properties Type de document : texte imprimé Auteurs : B. Haworth, Auteur ; U. N. Ratnayake, Auteur Année de publication : 2011 Article en page(s) : p. 91-99 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Argile Dispersions et suspensions Ecoulement cisaillé Matériaux hybrides Montmorillonite Polymères -- Additifs Polypropylène Index. décimale : 668.9 Polymères Résumé : Layered structures in inorganic minerals are not easily intercalated when combined with conventional non-polar polymers such as polypropylene (PP). A new co-intercalation method is reported whereby the combined influence of low molecular weight polar additives and polyolefin-based compatibilizers on PP-clay nanocomposites (PPCN) has been investigated. Our research has shown that the interlayer spacing of montmorillonite clay increases dramatically, and increased particle dispersion is achieved, when short chain, organic additives (typically amidetype, AM) are included. In this work, the migration of these additives into the clay galleries has been confirmed by surface energy data (from contact angle experiments) and by various capillary flow measurement techniques. Shear flow data have been used to interpret the mechanism of intercalation, following compound preparation using melt-state mixing processes. At relatively low concentrations, the erucamide molecules assist the intercalation process in nanocomposites; however if an excess of AM is apparent within the bulk polymer melt, unusual flow behavior is observed which can be attributed to wall slip. Modified melt elasticity is also obtained with the PPCN’s leading to reduced die swell characteristics in extrusion processes. Significant differences in melt flow behavior can therefore be attributed to the presence of AM; a mechanism for co-intercalation has been proposed in terms of hydrogen bonding between the additives and the silicate layers. DOI : 10.3139/217.2409 En ligne : https://drive.google.com/file/d/18BmekobMvn91EwgaGdQg2f9tWakUkZcW/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11068 [article]

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