Development of Domestic Taylor-flow Nanogrinder for Manufacturing Cellulose Nanofiber II : Evaluation of Physical Properties of Carboxymethylated Cellulose Nanofibers Made from Bleached Kraft Pulps

Abstract

In this study, we investigated the characteristics of carboxymethylated cellulose nanofibers (CM-CNFs) using a pilot scale Taylor-flow nanogrinder (pilot nanogrinder). Two types of CM-CNFs made from softwood bleached kraft pulp (SwBKP) and hardwood BKP (HwBKP) were prepared using the pilot nanogrinder via carboxymethylation. The CM-CNF samples were taken every hour in a six-hour grinding process, and then their particle size, fiber width, and low-shear viscosity were analyzed.BRThe fiber length, fiber width, fines content, and morphology of the carboxymethlyated SwBKP and HwBKP were not significantly changed, but their crystallinity was somewhat reduced after carboxymethylation. With increasing grinding time for carboxymethylated BKPs, the fiber width of CM-CNFs decreased linearly. However, the particle-size analysis results were not reasonable compared to the references, which indicated that the laser diffraction method was inefficient for particle-size determination for the transparent CM-CNFs. The low-shear viscosity of CM-CNFs increased linearly with the grinding time. The CM-CNF made from SwBKP showed lower fiber width and higher low-shear viscosity than that made from HwBKP. Therefore, it was concluded that CM-CNFs made from BKPs could be manufactured using the pilot scale Taylor-flow nanogrinder, and SwBKP was more effective to produce CM-CNF with lower fiber width and higher viscosity than HwBKP.