Reduction of Fibrillation of Lyocell Fiber with Cellulose-g-Poly(vinyl alcohol) Copolymer

Cellulose-g-poly(vinyl alcohol) (cellulose-g-PVA) copolymers, which contain vinyl alcohol(VA) content 13, 36, and 47 wt%, were prepared, and the effects of introducing the copolymers on the fibrillation of lyocell fibers were investigated. Five wt% copolymer to cellulose was added to 13 wt% cellulose solution in N-methyl morpholine N-oxide (NMMO) monohydrate and lyocell fibers were produced by dry jet-wet spinning of cellulose/cellulose-g-PVA blend solutions. Variation of VA content had little effect on crystal structure and mechanical properties of lyocell fibers. However, the birefringence of the fibers decreased with increasing VA content. In the case of lyocell fibers containing the copolymer with VA content 47 wt%, microfibril structure in the cross-section of fractured fibers disappeared. The VA group of the copolymers thus interrupts the orientation of cellulose chains due to strong hydrogen bonding. Fibers containing the copolymers gave less fibrillation than lyocell fibers, which became more noticeable at higher VA content. Addition of copolymers proved effective for the control of fibrillation of lyocell fiber.