Viscoelasticity of Xanthan and Hydrolytic Polyacrylamide Mixed Aqueous Solutions

The viscoelasticity of Xanthan (XC) and hydrolytic polyacrylamide (HPAM) mixture in aqueous solution was studied. The effects of mixing proportion of the two polymers on its viscoelastic properties was determined, as well as its heat and salinity tolerance abilities. It is shown that, when the mixing proportion is 1:5 (XC/HPAM), the steady-shear viscosity of the mixture is higher than that of pure XC or HPAM aqueous solution. Moreover, the mixture of 1:5 XC/HPAM shows a much stronger heat and salinity tolerance abilities comparing with pure XC or HPAM aqueous solution. A proposed mechanism for the steady-shear viscosity increasing is that hydrogen-bonded complexes are formed, which leads to polymer chains more elongated. On the other hand, the larger hydrodynamic radius of hydrogen-bonded complexes is also a reason for the enhanced viscosity.