Effect of introducing long chain branching on fiber diameter and fiber diameter distribution in melt blowing process of polypropylene / K. Iiba in INTERNATIONAL POLYMER PROCESSING, Vol. 36, N° 4 (2021)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. 36, N° 4 (2021) . - p. 403-409 Titre : Effect of introducing long chain branching on fiber diameter and fiber diameter distribution in melt blowing process of polypropylene Type de document : texte imprimé Auteurs : K. Iiba, Auteur ; W. Takarada, Auteur ; Takeshi Kikutani, Auteur Année de publication : 2021 Article en page(s) : p. 403-409 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Extrusion filage Mesure Polymères ramifiés Polypropylène Procédé de fusion-soufflage (nontissés) Procédés de fabrication par voie fondue (nontissés) Rhéologie Index. décimale : 668.4 Plastiques, vinyles Résumé : In the melt blowing process, the molten polymers extruded from nozzles are elongated by high-velocity and high-temperature air flow. In this study, with the aim of stabilizing the melt blowing process for producing nonwoven webs with fine diameter fibers, the effect of the control of polymer rheology by the introduction of either low melt flow rate (MFR) polypropylene (PP) or long chain branched PP (LCB-PP) to regular high MFR PP was investigated. Introduction of low MFR PP into regular PP increased shear viscosity and fibers of larger diameter were produced in the melt blowing process, while introduction of low MFR LCB-PP suppressed the elongational viscosity reduction with the increase of strain rate, and eventually spinning was stabilized. It was found that the blending of an optimum amount of LCB-PP to regular PP caused the stabilization of the melt blowing process. As a result, the formation of nonwoven webs consisting of fine fibers of rather uniform diameter distribution could be achieved. Note de contenu : - Experimental : Raw materials - Rheological measurements - Spinning equipment and conditions - Measurement of fiber diameter - Observation of fiber formation behavior - Measurement of specific surface area - Results and discussion : Strain rate dependency of shear and elongational viscosity - Diameter of melt blown fibers - Observation of spinning-line - Specific surface area - Table 1 : Sample polymers for melt blowing process - Table 2 : Parameter of fiber diameter distribution calculated from fitted log-normal distribution curve. Values of the fitting parameters in equation 1 are also shown DOI : https://doi.org/10.1515/ipp-2020-3922 En ligne : https://drive.google.com/file/d/19WzVPEssiN-opvXNGkY74imxiOMO-sgY/view?usp=shari [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36713 [article]

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Effect of mutual interaction between high and low stereo-regularity components on structure formation in melt spinning process of isotactic polypropylene blend fibers / K. Kawai in INTERNATIONAL POLYMER PROCESSING, Vol. XXXIII, N° 3 (07/2018)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXIII, N° 3 (07/2018) . - p. 387-396 Titre : Effect of mutual interaction between high and low stereo-regularity components on structure formation in melt spinning process of isotactic polypropylene blend fibers Type de document : texte imprimé Auteurs : K. Kawai, Auteur ; W. Takarada, Auteur ; Takeshi Kikutani Année de publication : 2018 Article en page(s) : p. 387-396 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermique Diffraction des rayons X à grand angle Extrusion filage Mélanges de fibres Mesures physiques Polymères isotactiques Polypropylène Index. décimale : 668.4 Plastiques, vinyles Résumé : Fiber formation behavior of the blend fibers consisting of two types of isotactic polypropylene (iPP), i. e. high stereo-regularity/high molecular weight iPP (HPP) and low stereo-regularity/low molecular weight iPP (LPP), was investigated. In the melt spinning of blend fibers of various HPP:LPP compositions, the spinnability was improved significantly not only by blending LPP into HPP but also by blending HPP into LPP. On-line diameter measurement of the spin-line revealed that the increase of LPP composition caused the shift of solidification point to downstream, indicating that the crystallization temperature was lowered. Wide-angle X-ray diffraction (WAXD) analysis of the as-spun fibers clarified that only the α-form crystal was formed, and the crystalline orientation increased with the increases of take-up velocity and HPP weight fraction. The crystallinities obtained from the WAXD patterns of the as-spun fibers of various HPP/LPP compositions prepared at the take-up velocity of 1 and 5 km/min were lower than the values estimated based on the rule of additivity, where the difference was more prominent for the 1 km/min fibers. Analyses of crystallinity through differential scanning calorimetry measurements also suggested the suppression of the crystallization of HPP in the HPP/LPP blend fibers. The thermal analyses basically clarified that in the melt spinning process of the blends of HPP and LPP, both components crystallized independently even though the two polymers are considered to be miscible in the molten state, however, detailed analyses of melting behavior of the as-spun fibers suggested the possibility of the formation of crystals with a certain level of mixing of the HPP and LPP molecules, i. e. the mixing of a certain amount of LPP molecules into the HPP crystals and also the mixing of a certain amount of HPP molecules into the LPP crystals. Note de contenu : - EXPERIMENTAL : Materials - Melt spinning - On-line diameter measurement - Wide-angle X-ray diffraction - Differential scanning calorimetry - RESULTS AN DISCUSSION : Spinning behavior - WAXD analysis of as-spun fibers - Thermal analysis of as-spun fibers DOI : 10.3139/217.3576 En ligne : https://www.degruyter.com/document/doi/10.3139/217.3576/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30808 [article]

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Effect of the control of polymer flow in the vicinity of spinning nozzle on mechanical properties of poly(ethylene terephthalate) fibers / M. Masuda in INTERNATIONAL POLYMER PROCESSING, Vol. XXV, N° 2 (05/2010)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXV, N° 2 (05/2010) . - p. 159-169 Titre : Effect of the control of polymer flow in the vicinity of spinning nozzle on mechanical properties of poly(ethylene terephthalate) fibers Type de document : texte imprimé Auteurs : M. Masuda, Auteur ; W. Takarada, Auteur ; Takeshi Kikutani, Auteur Année de publication : 2010 Article en page(s) : p. 159-169 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : In the melt spinning of PET, effects of the variation of flow behavior in the vicinity of spinning nozzle on the mechanical properties of as-spun fibers and drawn fibers were investigated. The variation of flow behavior was introduced by the change of spinning nozzle diameter and by the irradiation of CO2 laser to the spin-line at a position immediately below the spinneret. The curve representing the correlation between strength and elongation at break of as-spun fibers shifted toward the upper-right direction by the applications of small diameter nozzle and laser irradiation, indicating that the toughness of as-spun fibers was improved. The two-stage continuous drawing of as-spun fibers with various draw ratios revealed that the correlation between strength and elongation of drawn fibers also shifted toward the upper-right direction by the application of small diameter nozzle and laser irradiation. In other words, improved toughness in the as-spun fibers was preserved in the drawn fibers. Accordingly, by the drawing of the as-spun fibers prepared by the combination of small-diameter nozzle and laser irradiation, high-strength and high-toughness PET fibers with the tensile strength of 1.68 GPa (12.1 cN/dtex) and the elongation at break of 9.1% was obtained. Numerical simulation of the melt spinning process incorporating the effects of nozzle diameter variation and laser irradiation heating indicated that the maximum Deborah number in the spin-line decreased by the applications of small diameter nozzle and laser irradiation heating. Accordingly, it was speculated that the variation of the state of molecular entanglement caused by the difference of polymer flow in the melt spinning process has significant effect on the mechanical properties of resultant fibers. Note de contenu : EXPERIMENTAL : Melt spinning process - Measurement of fiber properties - Numerical simulation of the melt spinning process. RESULTS AND DISCUSSION : Structures and properties of as-spun fibers - Structure and properties of drawn fibers DOI : 10.3139/217.2330 En ligne : https://drive.google.com/file/d/16NB9uhQcItcg_weSFL4mE3JCiNRK28aa/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9330 [article]

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Fine filament formation behavior of polymethylpentene and polypropylene near spinneret in melt blowing process / R. Ruamsuk in INTERNATIONAL POLYMER PROCESSING, Vol. XXXI, N° 2 (05/2016)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXI, N° 2 (05/2016) . - p. 217-223 Titre : Fine filament formation behavior of polymethylpentene and polypropylene near spinneret in melt blowing process Type de document : texte imprimé Auteurs : R. Ruamsuk, Auteur ; W. Takarada, Auteur ; Takeshi Kikutani, Auteur Année de publication : 2016 Article en page(s) : p. 217-223 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Etat fondu (matériaux) Filature Matières plastiques -- Soufflage Mouvement rotatoire Polyméthylpentène Le polyméthylpentène (de sigle PMP ou TPX) est un polymère thermoplastique de la famille des polyoléfines. Son nom dans la nomenclature IUPAC est poly(4-méthylpent-1-ène). Il résulte de la polyaddition du monomère 4-méthylpent-1-ène (numéro CAS 691-37-2) avec catalyse de Ziegler-Natta. Les produits disponibles dans le commerce sont généralement des copolymères. Ils peuvent être extrudés et moulés par moulage par injection ou par moulage par soufflage. À température ambiante, il est parfaitement transparent (bien qu'il soit semi-cristallin) et très perméable aux gaz. Il est hydrophobe, autoclavable à 135 °C et résiste pendant une courte durée à une température d'environ 175 °C (dépend des grades disponibles). Le PMP se classe parmi les polymères thermoplastiques les plus thermostables. Sa température de fusion est élevée, de 230 à 240 °C. Sa densité, de 0,83, est la plus faible des polymères thermoplastiques. Sa rigidité est similaire au polypropylène (PP). Sa résistance à l'oxydation est inférieure à celle du PE. On doit donc lui incorporer des additifs antioxydants. Il est couramment utilisé pour le matériel médical et de laboratoire, mais aussi en cuisine ou pour des composants électroniques. Polypropylène Index. décimale : 668.4 Plastiques, vinyles Résumé : Formation behavior of fine fibers of polymethylpentene (PMP) and polypropylene (PP) in the melt blowing process was investigated through the observation of the spin-line near the spinning nozzle using a high speed camera. Reduction of the polymer throughput rate and increase of the air flow rate were necessary to achieve fine diameter fibers, however these conditions generally cause the instability in the spinning process. Observation of the spin-line at the melt blowing die revealed the periodic accumulation of polymer flow near the spinning nozzle followed by the quick pulling down of the accumulated polymer by the air flow. This behavior caused the periodic fluctuation of fiber diameter as well as the intermittent breakage of the spin-line under extreme conditions. Because of high extrusion viscosity, PMP showed more stable spinning behavior than PP. Frequency of diameter fluctuation became higher with the increases of air flow rate and throughput rate, and the maximum frequency of about 60 Hz was observed for PP spinning with the throughput rate of 0.18 g/min. Diameter distribution of the fibers in the prepared web was also analyzed to compare with the spinning behavior. Fiber diameter distributions were narrow and symmetric under stable spinning conditions, whereas skewed diameter profiles with a maximum at low value and a long tail to the larger diameter region were observed under unstable conditions. Intermittent spin-line breakage caused flaws of "shot" and/or "fly", and the skewed fiber diameter distribution with the presence of a small amount of fiber of extremely large diameter was confirmed. Note de contenu : - EXPERIMENTAL : Materials - Melt blowing equipment and conditions - In-situ observation - Analysis of fiber diameter distribution - RESULTS AND DISCUSSION : Fiber formation behavior near spinneret - Fiber diameter distribution - Estimation of fiber velocity - Some consideration on instability DOI : 10.3139/217.3163 En ligne : https://drive.google.com/file/d/1b9rnzo6zxa4c_0sJGSD0MJiEqWQNWYrE/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26179 [article]

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High-speed melt spinning of polyethylene terephthalate with periodic oscillation of take-up velocity / W. Takarada in INTERNATIONAL POLYMER PROCESSING, Vol. XIX, N° 4 (12/2004)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XIX, N° 4 (12/2004) . - p. 380-387 Titre : High-speed melt spinning of polyethylene terephthalate with periodic oscillation of take-up velocity Type de document : texte imprimé Auteurs : W. Takarada, Auteur ; K. Kasama, Auteur ; Hiroshi Ito, Auteur ; Takeshi Kikutani, Auteur Année de publication : 2004 Article en page(s) : p. 380-387 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : To investigate the non-steady-state melt spinning behavior, take-up velocity was varied periodically in the high-speed melt spinning process of polyethylene terephthalate and the timecourse changes of velocity and diameter of the spin-line were measured simultaneously. A numerical simulation program for the non-steady-state melt spinning process was also developed. In the range of relatively low take-up velocities, experimental results and results of numerical simulation of the non-steadystate melt spinning process showed a fair agreement, in that the amplitude for the variation of the reciprocal of the crosssectional area and that for the variation of velocity of the spin-line had a linear relation. An increase in the frequency of velocity oscillation led to a less significant variation in the thickness of as-spun fibers. On the other hand, there was a phase shift between the oscillation of take-up velocity and that of the reciprocal of cross-sectional area of the spin-line at the point of take-up. When take-up velocity was increased, starting of the orientation-induced crystallization along with the occurrence of neck-like deformation caused some characteristic behaviors such as significant increases in the amplitudes of velocity and diameter fluctuations at a certain region in the spin-line. Such behaviors could be reproduced in the numerical calculation by incorporating the stress dependent change of solidification temperature. It was also revealed that the orientation-induced crystallization has the effect of stabilizing the spinning system. DOI : 10.3139/217.1849 En ligne : https://drive.google.com/file/d/1auL-E5JomBFYy9ti7eoJAV8uR4Stq9Rh/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3271 [article]

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On-line measurement studies on orientation development and characteristic short-period diameter fluctuation in high speed in-line drawing of polyethylene terephthalate fiber / W. G. Hahm in INTERNATIONAL POLYMER PROCESSING, Vol. XXIV, N° 3 (07/2009)  

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