The effect of molar mass and charge density of cationic polyacrylamide on the flocculation of dissolved and colloidal substances in thermomechanical pulp water

Cationic polyacrylamides (C-PAM) with various molor masses and charge densities were added to thermomechanical pulp water to investigate their effect on dissolved and colloidal substances. These anionic substances originate from mechanical pulp and can interfere with the action of cationic polymers. The results show that the most effective flocculation of extractives was obtained by C-PAM with a molar mass of 9 center dot 10(6) glnzol and a charge density of 3.2 meq/g. The extractives affected most by C-PAM were the triglycerides and steryl esters. The negative charge of the water samples was reduced with C-PAM. This correlated well with the reduced extractive concentrations after C-PAM addition.