Effect of natural additives on the rheological properties of cellulose fiber disperse systems

Some polysaccharides were added to cellulose fiber disperse systems to improve their rheological properties. The viscoelastic properties of the systems were measured with a parallel-plates or a cone-plate type rheometer. For the thin systems, their flocculation behaviors were also observed with a high-speed camera as well as the flow properties. Although Tororoaoi mucilage, which is used as a dispersant in the Japanese traditional papermaking, had no effect on the systems, guar gum and xylan had preferable effects on reducing the dynamic moduli. For all the systems, a power law relation was found between the dynamic moduli and the fiber concentrations; however, the exponent value was varied with the addition amount and kind of the polymers. These additives had no significant effect on reducing flocculation of the systems but preferable effect on reducing the stress leaps of the systems. The sedimentation volume measurements well represent the effect of the added polysaccharides. These results indicate that the addition of guar gum or xylan reduces the friction at the fiber contact points; and moreover, it makes the fibers lie in the better order and laminate more regularly.