Response of Kenaf Woody Core to Chemimechanical Treatments: The Effect of Water and Alkali Soaking on Water Retention Value and Yield, 1999 Pulping Conference Proceedings

Medwick V. Byrd, Jr.

Department of Wood & Paper Science

NC State University

Woody core makes up 55-65 % of the weight of whole-stalk kenaf. This core has shorter fiber length and higher lignin content than the bast portion, so it responds much differently to chemical and mechanical pulping treatments. The purpose of this work was to characterize the response of core to typical chemimechanical treatments, in order to optimize the quality of high-yield pulps from whole-stalk kenaf. Core samples were subjected to soaking in water and alkaline solutions for various times. NaOH concentration, temperature, and time were varied. After soaking, the degree of fiber saturation was estimated using water retention value. Yield was also measured. For soaking in water, kenaf core was able to pick up three times its weight in water within thirty minutes, and the pickup increased to approximately six times over the next four days. Pickup and yield loss were all higher when the water temperature was increased. For soaking in alkaline solutions, only temperature had a significant positive effect on water retention value (WRV). All three variables had a significant negative effect on yield. Yield and WRV were found to be inversely related.