| Titre : |
Quantifying extrusion modification of LDPE with a microcompounder |
| Type de document : |
texte imprimé |
| Auteurs : |
T. Li, Auteur ; K. Kuklisin, Auteur ; J. Auger, Auteur ; J. Nielsen, Auteur ; W. Lin, Auteur |
| Année de publication : |
2012 |
| Article en page(s) : |
p. 91-97 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Chromatographie sur gel
Ecrouissage
Malaxeurs et mélangeurs
Matières plastiques -- Extrusion
Poids moléculaires
Polyéthylène basse densité
Résonance magnétique nucléaire
Rhéologie
|
| Index. décimale : |
668.9 Polymères |
| Résumé : |
Processibility of LDPE is known to be sensitive to processing history. Significant changes in processibility and product properties can occur through repeated extrusion without detectable changes in molecular weight and molecular weight distribution. Such changes of LDPE rheology are simulated with DSM micro-compounder and characterized with the small angle oscillatory tests and the SER uni-axial extensional flow with a K-BKZ analysis. Both the linear and the nonlinear rheology data suggest the major mechanism in the extrusion with the DSM micro-compounder is the reduction of the effects of long chain branching. The linear rheology analysis, along with GPC and NMR characterization confirms that the changes in the extrusion are not due to chemical crosslinking, though an increase in backbone molecular weight at extreme conditions is perceivable through the minor increase in molecular weight distribution, the increase in zero-shear viscosity and the decrease of melt index. The extensional rheology results, on the other hand, reveal the depression of the strain hardening with prolonged extrusion at 190 degree C or higher extrusion temperature. The stress growth data were evaluated with a K-BKZ constitutive with exponential damping function. The depression of strain hardening is well characterized with the strain hardening factor and the non-linear exponent beta as function of the extrusion conditions. The damping factor β is observed to be especially effective as the parameter to follow the depression of the strain hardening due to microcompounder extrusion. The microcompounder extrusion and the SER analysis with the KBKZ analysis prove to be a new useful tool for simulating the shear modification of the LDPE. |
| Note de contenu : |
- LINEAR AND NON-LINEAR RHEOLOGICAL ANALYSES
- EXPERIMENTAL : GPC - NMR
- RESULTS AND DISCUSSION : Linear viscoelastic properties |
| DOI : |
10.3139/217.2421 |
| En ligne : |
https://drive.google.com/file/d/1ILOBQQEN2Z6ZMbi9-ZmRaV-d3bo-Zd4B/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13737 |
in INTERNATIONAL POLYMER PROCESSING > Vol. XXVII, N° 1 (03/2012) . - p. 91-97
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