Fundamental study on the cellulose nanofibril manufacture from paper mulberry fiber

Abstract

Bast fibers, such as mulberry, flax, and hemp, are more durable and stronger than lignocellulosic fibers because of their high cellulose content and high crystallinity. Although studies on pulping and fiberization of bast fibers have been undertaken, research on bast fiber industrialization is lacking. A novel grade of the product made using bast fibers should be explored to extend their application in the industry. In this study, a cellulose nanofibril (CNF) was produced using paper mulberry fibers via refining and micro-grinding processes. After micro-grinding, the fiber width, viscosity, particle size, and zeta potential of the CNF samples were measured to evaluate the CNF properties depending on the pass number of fibrillations. Both external and internal fibrillations were observed during the refining process. The fiber width and particle size of the CNFs decreased and the CNF viscosity increased as the pass number of fibrillations in the micro-grinding process increased. The fiber widths of all the CNFs were smaller than 100 nm when the pass number was 8, indicating that paper mulberry fibers could be used as a raw material for the CNF manufacture. However, compared with the CNFs made from lignocellulosic fibers, only mechanical pretreatment was not effective, and a longer fibrillation time was required for the paper mulberry CNF manufacture. Therefore, we conclude that chemical or enzymatic pretreatment is needed prior to CNF refining and micro-grinding to improve the efficiency of paper mulberry CNF manufacture. ? 2019 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.