Effect of Molecular Weight and Flow Type on Flow Birefringence of Dilute Polymer Solutions
Birefringence measurements can be used to study conformation changes in a polymer solution due to the presence of flow. In the dilute concentration range, such studies have been carried out for simple shear flow1 and uniaxial extensional flow,2 but only for a single molecular weight in each case and for concentrations above 300 ppm. Neither the effect of flow type nor molecular weight has been adequately investigated, though each may be extremely important in “applications” such as the well-known “drag reduction” phenomenon. The present paper summarizes the results of flow birefringence experiments for 50 and 100 ppm solutions of three different MW samples of polystyrene dissolved in a viscous poly-chlorinated biphenyl solvent. A range of two-dimensional flow types was generated using a four roll mill.
KeywordsDrag Reduction Flow Type Roll Mill Velocity Gradient Tensor Simple Shear Flow
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