Diameter profile measurements for CO2 laser heated drawing process of PET fiber / W. Okumura in INTERNATIONAL POLYMER PROCESSING, Vol. XVIII, N° 1 (03/2003)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 1 (03/2003) . - p. 46-52 Titre : Diameter profile measurements for CO2 laser heated drawing process of PET fiber Type de document : texte imprimé Auteurs : W. Okumura, Auteur ; T. Kanegae, Auteur ; Y. Ohkoshi, Auteur ; Y. Gotoh, Auteur ; M. Nagura, Auteur Année de publication : 2003 Article en page(s) : p. 46-52 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Poly (ethylene terephthalate) (PET) fiber was heated by carbon dioxide laser radiation in the continuous drawing process. By this procedure, the position of the deformation region could be fixed precisely in the air. The location of neck-like deformation fluctuated within a range of about 0.2 mm for draw ratios of 4.0 to 4.5 and within a range of about 0.5 mm for draw ratios of 5.5 to 6.0, but the location fluctuated over a range of 1.0 mm for a draw ratio of 5.0. Fiber diameter profiles, which were used to calculate Hencky strain rate profiles and apparent elongational viscosity profiles, were obtained from high-speed video camera images of the deformation region. Regardless of draw ratio, apparent elongational viscosity exhibited almost the same minimum value. Apparent elongational viscosity is much lower than the value obtained by measurement at a low, constant strain rate, but the elongational stress acting at the point where apparent elongational viscosity begins to increase steeply (Hencky strain of about 1.0) is of the same order of magnitude as the reported value. For draw ratios less than 5.0, the temperature where apparent viscosity is lowest is about 100 to 120°C, which corresponds to the flow temperature of amorphous PET, whereas for draw ratios exceeding 5.0 the temperature where apparent viscosity is lowest is about 80°C, which corresponds to the glass transition temperature. Thus, the former corresponds to so-called neck-like deformation typically observed in high-speed spinning, and the latter corresponds to necking typically observed in cold drawing. These two types of deformation appear in turns for a draw ratio of 5.0, and therefore the location of the deformation region fluctuates greatly. This measurement system can be used as a high-strain-rate elongational rheometer for analyzing practical polymer processing systems, which can easily measure the precise on-line deformation history with a time resolution in the μs level. DOI : 10.3139/217.1717 En ligne : https://drive.google.com/file/d/18cpYQeUC2dJ8-nnMcvKYs8LJfHHYcDc-/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15850 [article]

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Direct measurement of fiber temperature in the continuous drawing process of PET fiber heated by CO2 laser radiation / W. Okumura in INTERNATIONAL POLYMER PROCESSING, Vol. XVII, N° 2 (06/2002)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVII, N° 2 (06/2002) . - p. 124-132 Titre : Direct measurement of fiber temperature in the continuous drawing process of PET fiber heated by CO2 laser radiation Type de document : texte imprimé Auteurs : W. Okumura, Auteur ; T. Yamaguchi, Auteur ; Y. Ohkoshi, Auteur ; Y. Gotoh, Auteur ; M. Nagura, Auteur Année de publication : 2002 Article en page(s) : p. 124-132 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Poly(ethylene terephtalate) (PET) fiber was heated by carbon dioxide laser radiation during the continuous drawing process. Numerical calculation shows that the PET fiber can be heated much more rapidly and uniformly by heat radiation than by convective heat transfer through the fiber surface. During CO2 laser heated drawing, temperature in the vicinity of a neck-like deformation can be measured on-line with high precision, because the neck-like deformation is located within a range of 0.5 mm. We measured the fiber temperature profiles on the drawing process by IR thermometer that has a range resolution of 0.355 mm. The temperature at which neck-like deformation of the fiber initiates is higher than Tg when draw ratio is less than 4.5, but lower than Tg when draw ratio is more than 5.5. The maximum fiber temperature in the drawing process increases with draw ratio, up to 208°C for a draw ratio of 6.0. The rate of orientation-induced crystallization in the drawing process was estimated by comparison of measured temperature profiles with calculated temperature profiles. Note de contenu : - EXPERIMENTAL : Drawing system and material - Drawing tension - Density - Fiber temperature - DISCUSSION : Comparison of radiation heating and conduction heating from fiber surface - Numeraical calculation of fiber temperature profiles - APPENDIX : Absorption coefficient - Temperature distribution in the fiber cross-section - Absorptance of fiber DOI : 10.3139/217.1684 En ligne : https://drive.google.com/file/d/1eOzKEBB28dFq9HOJwrpxLtnhdtZ96iWb/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15932 [article]

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