Differences and similarities between kraft and oxygen delignification of softwood fibers: effects on chemical and physical properties

Abstract The fiber properties after oxygen delignification and kraft pulping were studied by looking into the chemical characteristics morphology. effect of two processes on fibers was evaluated compared over a wider kappa number range (from 62 down to15). Wide-angle X-ray scattering, nuclear magnetic resonance saturation point used to characterize network structure. Fiber morphology dislocations an optical image analysis. total surface charges conductometric polyelectrolyte titrations. wall supramolecular structure, such as crystallinity, size fibril aggregates, pore volume, similar for processes. selectivity, in terms carbohydrate yield, equal cooking delignification, but selectivity viscosity loss per amount is poorer delignification. Clearly more deformations (2–6% units curl index) seen. Introduction depended physical state fibers, i.e. liberated or wood matrix. In stage, continue be supported neighboring delignified chips maintain their form. However, subsequent stage enter form pulp (liberated fibers), which makes them susceptible changes Graphic abstract