Step Strain Deformations for Viscoelastic Fluids: Experiment

Shear stress and normal stress relaxation data were collected for a range of shear strains for a polystyrene—dibutyl phthalate solution. Data from single-step shear strain experiments were used to test time-strain factorability and to check on the applicability of the Lodge-Meissner rule. Significant departures from time-strain factorability were found, but the shear and normal stress data were in excellent agreement with the Lodge-Meissner prediction. Data from double-step shear strain experiments were used to check the predictions of the K—BKZ and Doi—Edwards theories. It was found that these theories do not generally provide adequate descriptions of double-step shear strain deformations.