Interactions between a cationic polyelectrolyte and cellulose fibres bleached for paper manufacture

From a bleached needle tree kraft paste, it is studied for a series of indu strial refining the cationic demand of the fibrose suspension, the part of the suspension without fines and the fines proportion. Cationic demand has been evaluated by means of the colloidal titulation technique. The results obtained suggest that the fixation of cationic polymer on the cellulose fib ers takes place mainly through the mechanism of ionic exchange for this ref ining interval (25-45 degrees SR). By means of theoretical calculations it has been proved that the specific s urface which presents the fines proportion is much bigger than the one corr esponding to the paste and to the part without fines; this fact is confirme d experimentally by a greater cationic demand.