Development of Domestic Taylor-flow Nanogrinder for Manufacturing Cellulose Nanofiber III -Evaluation of Physical Properties of Cellulose Nanofibers Manufactured with Scale-up Taylor-flow Nanogrinder-

Abstract

In this study, we attempted to manufacture a scale-up Taylor-flow nanogrinder by compensating the shortcomings of a pilot scale Taylor-flow nanogrinder derived from previous studies. Two types of cellulose nanofibers (CNFs) were prepared depending on the pretreatment using a scale-up Taylor-flow nanogrinder and their characteristics were measured to evaluate the grinding efficiency. The capacity of the grinder cylinder and the mixer increased respectively while increasing the capacity of a scale-up Taylor-flow nanogrinder. The size of the diamond particles electrodeposited on the surface of the stator and rotor, which were the components of the grinder cylinder, and the gap between the stator and rotor were reduced to improve the grinding efficiency. In addition, a multi-stage centrifugal pump was installed to induce a uniform flow of CNF slurry according to the increased grinder capacity. When RE-CNF (refining CNF) was manufactured from refined hardwood bleached kraft pulp (HwBKP) using a scale-up Taylor flow nanogrinder, the average particle size and fiber width decreased and the low shear viscosity decreased as the grinding time increased due to HwBKP fibrillation. However, considering the fiber width's average value and standard deviation, it was concluded that the refining pretreatment was not adequate for this facility. When EN-CNF (enzyme-pretreated CNF) was manufactured from enzyme-pretreated HwBKP using a scale-up Taylor flow nanogrinder, the particle size and fiber width decreased linearly as the enzyme dosage and the grinding time increased simultaneously. In particular, when the grinding was carried out for 5-6 h, the fiber width of EN-CNF decreased to 50 nm or less, and the standard deviation decreased. This meant that enzyme pretreatment was efficient for the manufacture of CNF using a scale-up Taylor-flow nanogrinder. Nevertheless, the optimum enzyme dosage and the grinding time should be confirmed carefully to acquire the desired qualities of EN-CNF.