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Steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers

Steady shear, small amplitude oscillatory shear (SAOS) and capillary break-up extensional measurements have been conducted to investigate the rheological properties of two different “rod-like” polymers (the polysaccharides, xanthan gum (XG) and scleroglucan (SGN)) both in aqueous solution, over a wi...

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Main Authors: Japper-Jaafar, Azuraien, Escudier, Marcel, Poole, Robert
Format: Conference or Workshop Item
Published: 2007
Subjects:
TJ Mechanical engineering and machinery
Online Access:http://eprints.utp.edu.my/2452/1/Modified_Abstract_submitted_for_AERC_2007_.doc
http://eprints.utp.edu.my/2452/
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spelling my.utp.eprints.24522010-07-30T07:38:26Z Steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers Japper-Jaafar, Azuraien Escudier, Marcel Poole, Robert TJ Mechanical engineering and machinery Steady shear, small amplitude oscillatory shear (SAOS) and capillary break-up extensional measurements have been conducted to investigate the rheological properties of two different “rod-like” polymers (the polysaccharides, xanthan gum (XG) and scleroglucan (SGN)) both in aqueous solution, over a wide range of concentrations (0.01% -0.75% w/w). Detailed shear viscosity measurements show that both polymers are strongly shear-thinning. Above a critical concentration (c*),  0.067% for XG and > 0.01% for SGN, the zero-shear-rate viscosity scales with concentration as approximately c5.18 for XG and c3.18 for SGN. SAOS measurements, only possible for relatively concentrated solutions (c/c* >> 1), show that the longest relaxation time also scales in a power-law like way. A capillary break up extensional rheometer (CaBER), in conjunction with a high speed camera recording at 2000 frames per second, was used to probe the extensional properties of the solutions, again these measurements were only possible for relatively high concentrations. In these CaBER tests the filament diameter was observed to thin exponentially over a significant period of the break-up process in agreement with the simple one-dimensional theory of Entov and Hinch (1997) for “ideal” elastic liquids. Relaxation times, or more correctly, characteristic times for uniaxial extensional stress growth together with an estimation of the steady uniaxial extensional viscosity were obtained from this data. Such relaxation times were found to scale approximately linearly with concentration, as  c1.3, for both polymers, although the steady uniaxial extensional viscosity was found to be slightly higher for the SGN solutions. 2007 Conference or Workshop Item PeerReviewed application/msword http://eprints.utp.edu.my/2452/1/Modified_Abstract_submitted_for_AERC_2007_.doc Japper-Jaafar, Azuraien and Escudier, Marcel and Poole, Robert (2007) Steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers. In: 4th Annual European Rheology Conference, 2007, Italy. http://eprints.utp.edu.my/2452/
institution Universiti Teknologi Petronas
building UTP Resource Centre
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Petronas
content_source UTP Institutional Repository
url_provider http://eprints.utp.edu.my/
topic TJ Mechanical engineering and machinery
spellingShingle TJ Mechanical engineering and machinery
Japper-Jaafar, Azuraien
Escudier, Marcel
Poole, Robert
Steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers
description Steady shear, small amplitude oscillatory shear (SAOS) and capillary break-up extensional measurements have been conducted to investigate the rheological properties of two different “rod-like” polymers (the polysaccharides, xanthan gum (XG) and scleroglucan (SGN)) both in aqueous solution, over a wide range of concentrations (0.01% -0.75% w/w). Detailed shear viscosity measurements show that both polymers are strongly shear-thinning. Above a critical concentration (c*),  0.067% for XG and > 0.01% for SGN, the zero-shear-rate viscosity scales with concentration as approximately c5.18 for XG and c3.18 for SGN. SAOS measurements, only possible for relatively concentrated solutions (c/c* >> 1), show that the longest relaxation time also scales in a power-law like way. A capillary break up extensional rheometer (CaBER), in conjunction with a high speed camera recording at 2000 frames per second, was used to probe the extensional properties of the solutions, again these measurements were only possible for relatively high concentrations. In these CaBER tests the filament diameter was observed to thin exponentially over a significant period of the break-up process in agreement with the simple one-dimensional theory of Entov and Hinch (1997) for “ideal” elastic liquids. Relaxation times, or more correctly, characteristic times for uniaxial extensional stress growth together with an estimation of the steady uniaxial extensional viscosity were obtained from this data. Such relaxation times were found to scale approximately linearly with concentration, as  c1.3, for both polymers, although the steady uniaxial extensional viscosity was found to be slightly higher for the SGN solutions.
format Conference or Workshop Item
author Japper-Jaafar, Azuraien
Escudier, Marcel
Poole, Robert
author_facet Japper-Jaafar, Azuraien
Escudier, Marcel
Poole, Robert
author_sort Japper-Jaafar, Azuraien
title Steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers
title_short Steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers
title_full Steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers
title_fullStr Steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers
title_full_unstemmed Steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers
title_sort steady shear, small amplitude oscillatory shear and capillary break-up extensional rheology measurements of rod-like polymers
publishDate 2007
url http://eprints.utp.edu.my/2452/1/Modified_Abstract_submitted_for_AERC_2007_.doc
http://eprints.utp.edu.my/2452/
_version_ 1738655194449707008
score 13.211869

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