Enzyme-assisted Mechanical Fibrillation of Bleached Spruce Kraft Pulp for Producing Well-dispersed and Uniform-sized Cellulose Nanofibrils

Abstract

Cellulose nanofibrils (CNFs) are bionanomaterials with many promising properties and great potential in composite applications. Herein, welldispersed 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 enzymeassisted process had a remarkable effect on the production of CNFs and made CNFs more appealing for nanotechnology applications and nanomaterial.

Enhancement of Hydrotropic Fractionation of Poplar Wood Using Autohydrolysis and Disk Refining Pretreatment: Morphology and Overall Chemical Characterization

“…The dominant peaks of OH-stretching and CH-stretching at 3450 cm −1 and 2920 cm −1 were presented in the entire spectra [26]. The peaks at 896 cm −1 and 1061 cm −1 were associated with C-H deformation vibrations and C-O-C stretching vibrations, respectively, these data showed typical cellulose structural characteristics as reported in many previous studies [27,28]. The band at 1460 cm −1 , 1514 cm −1 and 1596 cm −1 were assign to C-H deformation vibration, aromatic skeletal vibration and C=C benzene ring vibration of lignin, respectively [29,30].…”

High wet-strength, thermally stable and transparent TEMPO-oxidized cellulose nanofibril film via cross-linking with poly-amide epichlorohydrin resin

“…26 The peaks at 1429, 1110, and 896 cm À1 indicated the typical structure of cellulose found in all samples, which revealed that there were no signicant structural changes aer the cross-linking reaction. 27 As the PAE content increased, a peak was observed around 1633 cm À1 , corresponding to the amide group belonging to PAE. 19 Compared to the neat TOCN lm, a new band was observed around 1718 cm À1 , which was assigned to the C]O vibrations from the ester functions in the crosslinking network.…”

Impact of High Concentrations of Cellulose Fibers on the Morphology, Durability and Protective Properties of Wood Paint

“…The bands at 1592 cm −1 and 1460 cm −1 can be associated with the C=C benzene ring vibration of lignin and C-H deformation vibration, respectively [67]. The last two peaks at 1233 cm −1 and 1027 cm −1 are representative of the C-O stretching and the typical C-O-C stretching vibrations of cellulose [68], respectively. The exposure to the UV-B radiation results in an increase in the intensity of the peak at 1729 cm −1 , which is accompanied by a reduction in the signal of the peak at 1233 cm −1 .…”