Abstract: Creep and oscillation experiments were performed to measure the zero-shear viscosity(η₀) and storage modulus(G') of aqueous solution of partially hydrolyzed polyacrylamide(PHPA), respectively. The overlapping concentration(C^*) and crossover concentration(C^*) of PHPA solution were determined through the dependence of η₀ on solution concentration(C). Effects of temperature, pH value and electrolytes(NaCl and CaCl₂) on C^* and C^* were investigated. The results show that as temperature and electrolyte concentration are raised, η₀ and G' decrease while C^* and C^* increase gradually. The higher the electrolyte cation valence is, the more obvious the induced variation of viscosity and critical concentrations of PHPA solution is. With pH value increasing, η₀ and G' increase initially and decrease subsequently while C^* and C^* decrease first and increase afterwards.

Key words: Partially hydrolyzed polyacrylamide(PHPA), Viscosity, Critical concentration, Viscoelasticity