Enzyme-Assisted Mechanical Fibrillation of Bleached Spruce Kraft Pulp to Produce Well-Dispersed and Uniform-Sized Cellulose Nanofibrils

Abstract

Cellulose nanofibrils (CNFs) are bionanomaterials with many promising properties and great potential in composite applications. Herein, well-dispersed and uniform-sized cellulose nanofibrils were successfully obtained from commercially bleached softwood kraft pulp, resulting in yields of 79.15% via enzyme-assisted hydrolysis and subsequent homogenization. Field emission scanning electron microscopy (FE-SEM) confirmed the fiber morphology. The water retention value (WRV) was increased from 107% of original pulp to 1384% of the resulting CNFs, while crystallinity had no significant changes. Fourier transform infrared (FTIR) spectroscopy indicated that enzymes degraded a portion of hemicelluloses and residual lignin. CNFs subjected to enzymatic treatment and homogenization had a less entangled network, larger aspect ratio, and higher transmittance than those from pure mechanical treatment. They were well dispersed in an aqueous solution and uniformly sized in morphology, resolving the present challenge of nanomaterials tendency for agglomeration. These results revealed that the enzyme-assisted process had a remarkable effect on the production of CNFs and made CNFs more appealing for nanotechnology applications and nanomaterial.