Cross-Sections of Nanocellulose from Wood Analyzed by Quantized Polydispersity of Elementary Microfibrils

Abstract

Bio-based nanocellulose has been shown to possess impressive mechanical properties and simplicity for chemical modifications. The chemical properties are largely influenced by the surface area and functionality of the nanoscale materials. However, finding the typical cross-sections of nanocellulose, such as cellulose nanofibers (CNFs), has been a long-standing puzzle, where subtle changes in extraction methods seem to yield different shapes and dimensions. Here, we extracted CNFs from wood with two different oxidation methods and variations in degree of oxidation and high-pressure homogenization. The cross-sections of CNFs were characterized by small-angle X-ray scattering and wide-angle X-ray diffraction in dispersed and freeze-dried states, respectively, where the results were analyzed by assuming that the cross-sectional distribution was quantized with an 18-chain elementary microfibril, the building block of the cell wall. We find that the results agree well with a pseudosquare unit having a size of about 2.4 nm regardless of sample, while the aggregate level strongly depends on the extraction conditions. Furthermore, we find that aggregates have a preferred cohesion of phase boundaries parallel to the (110)-plane of the cellulose fibril, leading to a ribbon shape on average.

In-Depth Study of the Microcrystalline Cellulose Amino-Functionalization Efficiency

“…The concept of multimodal size distributions has recently been reported by another team using a simulation matching approach (Rosén et al, 2020). In contrast, the approach used here is based on Rietveld re nement and it enables more parameters to be tted from the experimental data.…”

“…The line shape was described with a Pearson VII function and a shape parameter of 1.88. The geometry of these crystallites was assumed to be that of a superellipsoid, as described in (Rosén et al, 2020). The smaller crystallites were modelled using the IV I unit cell assuming the absence of a preferred orientation, and only two parameters were re ned, crystallite diameter (the crystallites were considered spherical) and relative intensity.…”

Shear-free mixing to achieve accurate temporospatial nanoscale kinetics through scanning-SAXS: ion-induced phase transition of dispersed cellulose nanocrystals

“…1 In soft matter systems, SAXS can yield structural information regarding the size, shape and ordering of the individual nanoscale entity (i.e. the form factor) in dilute systems, including polymers, 2 proteins, 3 viruses, 4,5 nanofibers 6,7 and other nanoparticles. 8 In addition, the high brilliance and tunability of synchrotron X-rays allowed the sample environments to be tailored for new in situ studies, including e.g.…”

A Proposition for the Estimation of the Maximum Tensile Strength of Variously Charged Nanocellulosic Film Materials Provided by Vacuum Filtration

“…In terms of fibrillation, the carboxymethylated nanocellulose at a high apparent nanocellulose yield has a high content of elementary fibrils with a size of 2.4 nm [ 33 ] and the enzymatically treated fibres with a defibrillation energy of 2500 Kwh/tonne is probably fairly similar to what is classified as microfibrillar cellulose (with no charging) and also close to what is conceived as papermaking fines, judging from the results by Fischer et al [ 34 ].…”