scholarly journals Extensional viscosity for polymer melts measured in the filament stretching rheometer

2003 ◽  
Vol 47 (2) ◽  
pp. 429-441 ◽  
Author(s):  
Anders Bach ◽  
Henrik Koblitz Rasmussen ◽  
Ole Hassager
Keyword(s):  
Polymer Melts ◽  
Extensional Viscosity ◽  
Filament Stretching

Local versus integral measurements of the extensional viscosity of polymer melts

2009 ◽  
Vol 53 (6) ◽  
pp. 1363-1377 ◽  
Author(s):  
Teodor I. Burghelea ◽  
Zdeněk Starý ◽  
Helmut Münstedt
Keyword(s):  
Polymer Melts ◽  
Extensional Viscosity

The role of end-effects on measurements of extensional viscosity in filament stretching rheometers

1996 ◽  
Vol 64 (2-3) ◽  
pp. 229-267 ◽  
Author(s):  
Stephen H. Spiegelberg ◽  
David C. Ables ◽  
Gareth H. McKinley
Keyword(s):  
Extensional Viscosity ◽  
End Effects ◽  
Filament Stretching

Measurement technique and data analysis of extensional viscosity for polymer melts by Sentmanat extensional rheometer (SER)

2010 ◽  
Vol 49 (4) ◽  
pp. 359-370 ◽  
Author(s):  
Johanna Aho ◽  
Víctor H. Rolón-Garrido ◽  
Seppo Syrjälä ◽  
Manfred H. Wagner
Keyword(s):  
Data Analysis ◽  
Measurement Technique ◽  
Polymer Melts ◽  
Extensional Viscosity

Molecular Drag-Strain Coupling in Branched Polymer Melts

2000 ◽  
Vol 629 ◽  
Author(s):  
Richard J. Blackwell ◽  
Tom C. B. McLeish ◽  
Oliver G. Harlen
Keyword(s):  
Branch Point ◽  
Polymer Melts ◽  
Uniaxial Extension ◽  
Extensional Viscosity ◽  
Low Density Polyethylene ◽  
Model Parameters ◽  
Low Density ◽  
Branch Points ◽  
Nonlinear Rheology ◽  
Branched Polymer

ABSTRACTThe “pom-pom” model of McLeish and Larson (J. Rheol. 42, 81, 1998) provides a simple molecular theory for the nonlinear rheology of long chain branched polymer melts. The Edwards-de Gennes tube concept is used to derive a constitutive equation for a simple branched molecule composed of two star polymers linked by a single backbone chain. A feature of this model is that the backbone section of tube can stretch up to maximum length given by the maximum entropic drag-force from the arms, after which the star arms are withdrawn into the backbone tube. This produces a sharp transition in the extensional viscosity at this maximum stretch. This unphysical feature results from an over-simplification of the behaviour near the branch points.In this paper we introduce a simple treatment of the coupling between relaxed and unrelaxed polymer segments at branch-points. This allows for localised displacements of branch-point within a quadratic potential before maximum extension is reached. Displacing the branch-point reduces the length of arm outside the tube and so reduces in the drag on the star arms. This smoothes out the sharp transitions in extensional viscosity in the original “pom-pom” model at the cost of introducing an extra unknown parameter.This modification improves the prediction of the nonlinear rheology of H-polymers whose molecular structure is known. Alternatively, for polymers of unknown structure such as commercial Low Density Polyethylene, the model parameters may be fitted from linear viscoelastic and uniaxial extension data, to provide predictions for the behaviour in transient nonlinear shear and planar extension. By including local branch-point displacement we find improved agreement with the data for Low-Density Polyethylene.

An investigation on modelling and measurements of transient elongational rheology of polymer melts by SER testing platform

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Mahmoud Rajabian ◽  
Ghassem Naderi ◽  
Hamid Piroozfar ◽  
Mohammad H. Beheshty ◽  
Mohammad Samadfam
Keyword(s):  
Steady State ◽  
Simple Shear ◽  
Shear Flows ◽  
Polymer Melts ◽  
Elongational Viscosity ◽  
Extensional Viscosity ◽  
Molten State ◽  
Diffusion Term ◽  
Hencky Strain ◽  
Elongational Rheology

AbstractTransient elongational rheology of PP is investigated experimentally. A specifically designed fixture consisting of two drums mounted on a TA Instruments ARES rotational rheometer was used to measure the transient uniaxial extensional viscosity of two commercial grades polypropylene in the molten state. The Hencky strain was varied from 0.003 to 2 s-1 and the temperature was fixed at 180 oC. The measurements show that the steady state elongational viscosity was reached at the measured Hencky strains for polypropylene. Eslami and Grmela have recently introduced a reptation diffusion term arising from the intermolecular chain forces into the rigid FENE-P dumbbells model. The same approach has been used in this study to interpret the transient rheological data in both shear-free and simple shear flows.

A control scheme for filament stretching rheometers with application to polymer melts

2013 ◽  
Vol 194 ◽  
pp. 14-22 ◽  
Author(s):  
José Manuel Román Marín ◽  
Jakob Kjøbsted Huusom ◽  
Nicolas Javier Alvarez ◽  
Qian Huang ◽  
Henrik Koblitz Rasmussen ◽  
...  
Keyword(s):  
Polymer Melts ◽  
Filament Stretching ◽  
Control Scheme

A filament stretching device for measurement of extensional viscosity

1993 ◽  
Vol 37 (6) ◽  
pp. 1081-1102 ◽  
Author(s):  
V. Tirtaatmadja ◽  
T. Sridhar
Keyword(s):  
Extensional Viscosity ◽  
Filament Stretching
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