Abstract The molecular weight of partially hydrolyzed polyacryamide (HPAM) is determined by viscometry in most cases without considering the hydrolysis degree difference, the result deviation might be very large between different HPAM samples. This paper suggest that the hydrolysis degree of HPAM sample should be measured by acid-base titration in the experiment, and proper constant values for molecular weight calculation can be selected according to its hydrolysis degree.
