Influence of Fiber Properties on the Network Strength of Softwood and Hardwood Kraft Pulp Fibers from Different Stages of a Bleaching Sequence

Abstract

During chemical pulping and bleaching operations, fiber properties are gradually changed due to mechanical and chemical treatment. The changes in fiber properties, in turn, influence network strength, i.e., the rigidity of fiber networks. In this study, the influence of fiber length, lignin content, specific surface area, total charge, and fiber flexibility on the network strength of commercial unbleached and totally chlorine free (TCF) bleached (ozone and hydrogen peroxide) softwood and hardwood kraft pulp suspensions have been investigated. The fiber length, total lignin content, and total charge decreased together with the network strength along the fiber line while the specific surface area and fiber flexibility increased. Correlations equal to or greater than 90% were found between network strength and fiber length, lignin content, specific surface area, and total charge. The interrelationship between the fiber properties indicated that for a given pulp, the total lignin content was the parameter that had the greatest influence on the network strength.