The Effect of CaCl2 on the Solution Behavior of Aromatic Polysulfonamide in Dimethylformamide

The solution behavior of aromatic polysulfonamide (PSA) in dimethylformamide (DMF) with the addition of CaCl2 was studied by rheology and viscosity measurements. It is shown that no maximum in its intrinsic viscosity as a function of CaCl2 concentration was observed and the relationship between ηsp and PSA concentration c is consistent with the predicted scaling of θ solvent for both DMF and DMF/4% CaCl2. However, the intrinsic viscosity, zero shear-rate viscosity and specific viscosity of PSA/DMF/4% CaCl2 were found larger than that of PSA/DMF, which could be related to the extending of PSA chain in solution due to the increase of the interaction between the PSA macromolecules and solvent with addition of CaCl2.