Effect of Lignin-Rich Microfiber on Handsheet Strength

This study explores the effects of using lignin-rich microfibers as a reinforcing material to enhance paper strength. The microfibers prepared by alkaline kneading of organosolv pulp for 1 to 3 hours were characterized in terms of fiber dimensions, residual lignin content, freeness, and water retention value. Longer alkaline kneading times were more effective for improved fiber micronization. In addition, freeness decreased and water retention value increased as a result of the kneading treatment. The microfibers were added at increasing amounts (1%, 3%, and 5% based on oven-dry weight) to commercial bleached kraft pulp to evaluate the effect of microfiber content on handsheet strength. The results showed that microfibers at a level of 5% increased the tensile index of the handsheet by up to 8%, indicating that lignin-rich microfibers have a high potential for use as paper strength additives.