ABSTRACT
Some wet end additives can interfere with the bonding between cellulose ˆbers. Such effects can either enhance or reduce the ability of those ˆbers to form a strongly bonded sheet of paper. However, the dry strengthening effect of chemical additives is generally smaller than the effects of pulp beating [22]. Moreover, even the effect of the dry-strength resin (DSR) depends on the degree of beating. In the case of cationic polyacrylamide [23], not only does the unbeaten pulp show a lower tensile index, but also a plateau, meaning that polymer adsorption is limited (Figure 6.1). Beaten pulp provides a higher dry strength for paper even in the absence of resin due to due to the tremendous increase in the conformability of the ˆber surface.
