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Analysis of film blowing with flow-enhanced crystallization / L. K. Henrichsen in INTERNATIONAL POLYMER PROCESSING, Vol. XXII, N° 2 (05/2007)
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Titre : Analysis of film blowing with flow-enhanced crystallization : Part 1. Steady-state behavior Type de document : texte imprimé Auteurs : L. K. Henrichsen, Auteur ; A. J. McHugh, Auteur Année de publication : 2007 Article en page(s) : p. 179-189 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : An analysis of the steady-state film blowing process based on a two-phase constitutive model that accounts for flow-enhanced crystallization is presented. The amorphous melt phase is represented by a multi-mode Giesekus constitutive equation with a transformation-dependent relaxation time and the semi-crystalline phase is represented by a rigid rod model. The relaxation times in the two constitutive equations are linked by an Avrami, temperature-dependent rate expression which contains a term in the Helmholtz free energy to account for flow-enhancement. Comparisons are made to experimental data for film blowing of linear low density (LLDPE) and low density (LDPE) polyethylenes. Excellent fits for the bubble radius, temperature, and crystallinity are shown. It is also shown that the ratio of amorphous stress to total stress at the "lock-in" point provides an excellent correlating variable for the elongation to break and yield strength properties of the as-blown film. Inclusion of multiple relaxation times in the Giesekus model offers insights on the controlling role of the maximum relaxation time in the stress profiles and locking-in behavior due to crystallization. DOI : 10.3139/217.1003 En ligne : https://drive.google.com/file/d/1QZGOhsT9_u02qLQSHDjzhuZRC0hdZvlm/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2758
in INTERNATIONAL POLYMER PROCESSING > Vol. XXII, N° 2 (05/2007) . - p. 179-189[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007141 - Périodique Bibliothèque principale Documentaires Disponible Analysis of film blowing with flow-enhanced crystallization / L. K. Henrichsen in INTERNATIONAL POLYMER PROCESSING, Vol. XXII, N° 2 (05/2007)
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Titre : Analysis of film blowing with flow-enhanced crystallization : Part 2. Linearized sensitivity and stability behavior Type de document : texte imprimé Auteurs : L. K. Henrichsen, Auteur ; A. J. McHugh, Auteur Année de publication : 2007 Article en page(s) : p. 190-197 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : An analysis of the transient film blowing process is presented based on the two-phase Giesekus/rigid rod model for flow-enhanced crystallization described in Part 1 [1]. Linearized frequency analysis has been used to explore the effects of system disturbances on the process. Results show that perturbations related to heat transfer and inflation pressure are more significant than the effects of film thickness (die swell). In addition, crystallinity is shown to have a consistent stabilizing effect on the system, with more crystallinity dampening the perturbations. Stability diagrams for each material show relatively wide regions of convergence in the blow-up ratio (BUR) – draw ratio space, however, at higher BURs (≥~4) the system becomes unstable for all DRs. DOI : 10.3139/217.1004 En ligne : https://drive.google.com/file/d/1D3duT4vuT_0XE5bmGQ1oT99c6NdZ6R1t/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2759
in INTERNATIONAL POLYMER PROCESSING > Vol. XXII, N° 2 (05/2007) . - p. 190-197[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007141 - Périodique Bibliothèque principale Documentaires Disponible