Derivation of a qualitative model for the spatial characteristic wavelength of extrusion flow instabilities: Investigation of a polybutadiene rubber through capillary, slit and complex geometry extrusion dies
Journal article, 2022

The extrusion flow instabilities of a commercial polybutadiene (PBD) are investigated as a function of different extrusion die geometries, such as round capillary, slit, and complex cross-section profile slit dies via capillary rheology. Qualitative models are used to fit the experimental data for the spatial characteristic wavelength (λ) of the appearing extrusion flow instabilities. A new qualitative model for the slit die geometry, rectangular cross-section, is derived based on the theoretical concept of the “two layers” extrudate and the force balance at the die exit region. The proposed qualitative model for the slit die geometry is used to predict the spatial characteristic wavelength (λ) for extrudates obtained by complex cross-section profile slit die geometries similar to industrial manufacturing. Correlation between the ratio of the extensional ( ) and shear ( ) stress at the die exit area and the characteristic dimension, height H for slit dies and diameter D for round capillary dies, is presented. Moreover, a geometry-dependent model is used to predict the spatial characteristic wavelength (λ) of the extrusion flow instabilities from a round capillary die to a slit die and vice versa.

polybutadiene

sharkskin.

qualitative modeling

extrusion die geometry

Extrusion flow instabilities

Author

Christos K. Georgantopoulos

Karlsruhe Institute of Technology (KIT)

Masood K. Esfahani

Karlsruhe Institute of Technology (KIT)

Michael A. Pollard

Karlsruhe Institute of Technology (KIT)

Ingo F.C. Naue

Karlsruhe Institute of Technology (KIT)

Andrea Causa

Pirelli Tyre S. p. A.

Roland Kádár

Chalmers, Industrial and Materials Science, Engineering Materials

Manfred Wilhelm

Karlsruhe Institute of Technology (KIT)

Macromolecular Materials and Engineering

1438-7492 (ISSN) 1439-2054 (eISSN)

Vol. 307 2200313

Subject Categories

Polymer Chemistry

Manufacturing, Surface and Joining Technology

Materials Chemistry

Areas of Advance

Building Futures (2010-2018)

Production

DOI

10.1002/mame.202200313

More information

Latest update

7/17/2024