Fibrillation tendency of cellulosic fibers—Part 4. Effects of alkali pretreatment of various cellulosic fibers

The effects of alkali type and the concentration in the alkali treatments on the weight loss in six cellulosic fibers and their influences on the fibrillation tendency were investigated. The fibril number of the cellulosic fibers pretreated with alkalis (FNpre) increased with increasing the alkali concentrations as well as the weight loss of the fiber except in the lyocell fiber treated in NaOH and KOH solutions. The FNpre in lyocell was reduced as the fibers were treated in 5 mol/l NaOH and KOH solutions. This result and the fact that the fibers were split in organic alkali such as tetramethylammonium hydroxide even at the low weight loss suggested that not only the loss of cellulose component but also reorganization of microfibril structure, inhomogeneous swelling of the fibers and other influences control the fibrillation tendency of cellulosic fibers.