Flow induced birefringence study of vortices in LDPE polymer melt extrusion

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70883521%3A28110%2F19%3A63523656" target="_blank" >RIV/70883521:28110/19:63523656 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Flow induced birefringence study of vortices in LDPE polymer melt extrusion

Original language description

During polymer melts extrusion wide range of unstable phenomena (die drool, slip-stick, wall slip, melt fracture etc.) can occur. These instabilities significantly limit production rate and decrease final product quality. Due to significant viscoelastic nature of polymer melts, secondary flows (vortices) inside the processing tools can also occur. In these vortices, polymer melt slowly rotates which significantly extends residence time at high processing temperature. This can lead to unwanted thermal degradation. Contrary to majority of flow instabilities visually detected on extrudate surface, vortices are always hidden inside processing tools. Thus, the study of them can only be done through visualization cells and special experimental techniques mapping velocity fields (particle tracking or laser-Doppler velocimetry) or stress fields (flow induced birefringence). Despite vortices are stress induced instability, theirs study is commonly performed through velocity fields only, which is however not fundamentally correct. This work is focused on development of novel method for study of vortices in polymer melt extrusion based on flow induced birefringence. Testing of the proposed method has been done for LDPE Lupolen 1840H polymer melt. Vortex boundary obtained from stress field have been directly compared with velocity one visualized through rotating gel particle tracking. Effect of temperature and shear rate on vortex area have also been studied and successfully correlated with laser-Doppler velocity data available in open literature for the same polymer melt and similar processing conditions.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

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OECD FORD branch

10404 - Polymer science

Project

<a href="/en/project/GA16-05886S" target="_blank" >GA16-05886S: Investigation the effect of polymer melt shear and elongational rheology on production stability of meltblown nanofibers and films</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2019

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

Annual Technical Conference - ANTEC, Conference Proceedings

ISBN

978-1-71380-198-6

ISSN

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e-ISSN

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Number of pages

5

Pages from-to

1253-1257

Publisher name

Society of Plastics Engineers

Place of publication

Dallas

Event location

Detroit

Event date

Mar 18, 2019

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

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