The effect of different polysaccharides on the development of paper strength during drying

The effect of different polysaccharides like cationic starch, guar gum, xyloglucan, chitosan, and carboxymethyl cellulose on the development of sheet tensile properties (tensile strength, breaking strain, tensile energy adsorption) and drying tension was studied with a method that resembled reasonably well the real drying process. The simplified model system, which was designed to emphasize the interactions between fiber and polymers, helped to distinguish the observed effect of polymers on the rheological behavior of paper. Each polymer and adsorption condition showed very characteristic development of tensile properties as a function of dry solids. The specific interactions between the polysaccharides and cellulose fibrils on fiber surfaces influenced adsorption, as well as the development of bonding and tensile properties during drying. Significant improvements in the development of tensile properties were attained with most of the tested polymers. Superior wet web strength and tensile properties through the drying range was achieved with carboxymethyl cellulose-chitosan bilayer adsorption technique. The development of drying tension was different to the development of tensile properties, suggesting that the mechanisms how polymers influence these properties are different.