Extensional viscosity of dilute polymer solutions

grantor: University of TorontoThe purpose of this study was to obtain reliable extensional viscosity measurements for dilute polymer solutions using a filament-stretching rheometer at the University of Toronto. Initial extensional measurements of two Newtonian fluids gave data very close to the expected values, which validated the experimental technique. Three dilute solutions of high-molecular-weight polystyrene in oligomeric styrene and the M1 fluid, were then tested. For the least viscous fluid, high strains were achieved and a steady-state Trouton ratio of about 900 was obtained, at all Deborah numbers. For the more viscous liquids, high strains were not achieved because the fluid filaments detached from their holders. Reasonable agreement was obtained in the data comparisons with MIT and Monash University using similar test techniques and the same fluids. The fact that the steady-state value of SM-1 was independent of the extensional rate suggests that this value could be used as a material property for SM-1.M.A.Sc