Flow properties for concentrated solution of chitosan were described in 50%HCOOH

50%CH3COOH

0.2mol/l HCl and 0.1mol/l CH3COOH+0.1mol/l CH3COONa under the concentration from 2 to 5g/100ml solvent. Flow equations presented in literature

such as Ferry equation

Cross equation and Ballauff equation

were tested from the point of view of the extrapolating method for evaluating the zero shear viscosities.The results of extrapolation were compared with the values measured by falling-ball method. It was shown that the method based on Cross eq-uation gave relatively good results.