Influence Of Molecular Weight Distribution on The Melt Extrusion Of High Density Polyethylene (HDPE): Effects Of Melt Relaxation Behavior on Morphology And Orientation in HDPE Extruded Tubular Films

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dc.contributorVirginia Techen
dc.contributor.authorYu, T. H.en
dc.contributor.authorWilkes, Garth L.en
dc.contributor.departmentChemical Engineeringen
dc.date.accessed2014-03-11en
dc.date.accessioned2014-03-26T17:35:14Zen
dc.date.available2014-03-26T17:35:14Zen
dc.date.issued1996-11-01en
dc.description.abstractThe influence of molecular weight distribution and extrusion processing variables on the morphological features and orientation of high density polyethylene (HDPE) uniaxially extruded tubular films was investigated. In order to gain a better understanding of the orientation-crystallization behavior occurring during extrusion processing, the melt flow properties of the two HDPE resins with identical <(M)over bar (n)> (14 600) values but different molecular weight distributions (<(M)over bar (w)>/<(M)over bar (n)> = 10.3, 15.1), utilized in our previous study, were characterized by dynamic rheological experiments over the temperature range from 150 degrees C to 230 degrees C within the angular frequency range from 0.1 to 100 rad/s. The experimental data were shifted to produce master flow curves. The how activation energy calculated from the shifting process was found to be 25.9 kJ/mol for resin 1 and 29.1 kJ/mol for resin 2. The characteristic relaxation time at 190 degrees C obtained by use of a Carreau-Yasuda analysis for resin 2 having the broader molecular weight distribution was found to be 6.5 times greater than that of resin 1. This observation further supports our previous conjecture that the prominence of the fibril nuclei in resin 2 is due to its longer melt relaxation time behavior. The extrusion processing variables of melt temperature at the die exit, quench height (which is the distance from the exit of the die to the cooling ring), flow rate of the air through the cooling ring, film line speed, and die gap were varied to control the melt relaxation time of HDPE resins and the processing time frame for cooling. The results show that a longer melt relaxation time and a shorter cooling processing time can enhance the formation of fibril nuclei. The importance of melt relaxation behavior in influencing the final morphological structure in HDPE extruded films and their associated properties is clearly made evident in this paper. (C) 1996 Society of Rheology.en
dc.description.sponsorshipHoechst Celanese Corporationen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationJ. Rheol. 40, 1079 (1996); http://dx.doi.org/10.1122/1.550801en
dc.identifier.doihttps://doi.org/10.1122/1.550801en
dc.identifier.issn0148-6055en
dc.identifier.urihttp://hdl.handle.net/10919/46797en
dc.identifier.urlhttp://scitation.aip.org/content/sor/journal/jor2/40/6/10.1122/1.550801en
dc.language.isoen_USen
dc.publisherAIP Publishingen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectTheoretical analysisen
dc.subjectCrystallizationen
dc.titleInfluence Of Molecular Weight Distribution on The Melt Extrusion Of High Density Polyethylene (HDPE): Effects Of Melt Relaxation Behavior on Morphology And Orientation in HDPE Extruded Tubular Filmsen
dc.title.serialJournal of Rheologyen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

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