Abstract
Afilament stretching rheometer (FSR) was used for measuring the start-up of uni-axial elongational flow
followed by reversed bi-axial flow, both with a constant elongational rate. A narrow molecular mass
distribution linear polystyrene with a molecular weight of 145 kg / mole wis subjected to the start-up
of elongation for three Hencky strain units and subsequently the reversed flow. The integral molecular
stress function formulation within the 'interchain pressure' concept agrees with the experiments.
In the experiments the Hencky strain at which the str~ss becomes zero (the recovery strain) in the
reversed flow has been identified. The recovery strain is found to increase with elongational rate, and has
a maximum value of approximately 1.45. The Doi Edwards model using any stretch evolution equation is
not able to predict the correct level of the recovery strain.
Original language | English |
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Journal | Journal of Non-Newtonian Fluid Mechanics |
Volume | 155 |
Issue number | 1-2 |
Pages (from-to) | 15-19 |
ISSN | 0377-0257 |
DOIs | |
Publication status | Published - 2008 |
Keywords
- FSR
- Reversed flow
- Bi-axial
- Uni-axial
- Filement stretching rheometer