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Cellulose is often described as a mixture of crystalline and amorphous material. A large part of the general understanding of the chemical, biochemical and physical properties of cellulosic materials is thought to depend on the consequences of the ratio of these components. For example, amorphous materials are said to be more reactive and have less tensile strength but comprehensive understanding...
The insufficient resolution of conventional methods has long limited the structural elucidation of cellulose and its derivatives, especially for those with relatively low crystallinities or in native cell walls. Recent 2D/3D solid-state NMR studies of 13C uniformly labeled plant biomaterials have initiated a re-investigation of our existing knowledge in cellulose structure and its interactions with...
Solvents that produce cellulose nanocrystals (CNCs) and promote cellulose fibrillation are of current interest. In this work, CNCs were fabricated from cotton at 80 and 100 °C using deep eutectic solvents (DESs) having choline chloride/oxalic acid dihydrate (OA) ratios of 1:1, 1:2 and 1:3. To investigate the side effects of the fabrication, the crystal structure and morphology of micro-sized treated...
Thin nanocellulose-based composite films (approximately 25 μm) were made with cellulose nanocrystals (CNCs), cellulose nanofibers (CNFs), and Zn(2-methylimidazolate anion)2 (ZM) modified CNFs for potential use in energy storage devices such as battery separators. The film morphology and surface wettability were studied in comparison with a commercial Polypropylene-Polyethylene-Polypropylene (PEP)...
The amount of secondary cell wall (SCW) cellulose in the fiber affects the quality and commercial value of cotton. Accurate assessments of SCW cellulose are essential for improving cotton fibers. Fourier transform infrared (FT-IR) spectroscopy enables distinguishing SCW from other cell wall components in a rapid and non-invasive way. Thus it has been used for monitoring SCW development in model plants...
Despite nomenclature conventions of the International Union of Pure and Applied Chemistry and the International Union of Biochemistry and Molecular Biology, the repeating unit of cellulose is often said to be cellobiose instead of glucose. This review covers arguments regarding the repeating unit in cellulose molecules and crystals based on biosynthesis, shape, crystallographic symmetry, and linkage...
The thickness of cotton fiber cell walls is an important property that partially determines the economic value of cotton. To better understand the physical and chemical manifestations of the genetic variations that regulate the degree of fiber wall thickness, we used a comprehensive set of methods to compare fiber properties of the immature fiber (im) mutant, called immature because it produces thin-walled...
Studies of cellulose aging and yellowing that involved a 1,4-dimethyl 3-keto β-d-glucoside (compound 1) model of oxidized cellulose led to a hemi-hydrated crystal of title compound 2 (1,6-dihydroxy-3,8-bis-hydoxymethyl-5,10-dimethoxy-4,9-dioxa-tricyclo [5,3,1,1,2,6] dodecane-11,12-dione). The same compound 2 was isolated in low yield from “real-world” oxidized and aged cellulosic pulp. Formation of...
Human neutrophil elastase (HNE) is one of a number of proteases that is receiving increased attention as a marker for inflammatory diseases and sensor-based point of care diagnostics. Integral to sensor-based detection is the transducer surface, which is the platform of the sensor’s signal transmittance. Here we describe the bioactivity and related transducer surface properties of cellulose and nanocellulose...
The chromophore release and identification method isolates well-defined chromophoric substances from different cellulosic matrices, such as highly bleached pulps, cotton linters, bacterial cellulose, viscose or lyocell fibers, and cellulose acetates. The chromophores are present only in extremely low (ppm to ppb) concentrations. The concept of primary and secondary chromophores is introduced, with...
Cellulose samples are routinely analyzed by X-ray diffraction to determine their crystal type (polymorph) and crystallinity. However, the connection is seldom made between those efforts and the crystal structures of cellulose that have been proposed with synchrotron X-radiation and neutron diffraction over the past decade or so. In part, this desirable connection is thwarted by the use of different...
Previous studies of calculated diffraction patterns for cellulose crystallites suggest that distortions that arise once models have been subjected to molecular dynamics (MD) simulation are the result of both microfibril twisting and changes in unit cell dimensions induced by the empirical force field; to date, it has not been possible to separate the individual contributions of these effects. To provide...
Introductory material first describes electron density approaches and demonstrates visualization of electron lone pairs and bonding as concentrations of electron density. Then it focuses on the application of Bader’s Quantum Theory of Atoms-in-Molecules (AIM) to cellulose models. The purpose of the work is to identify the various interactions that stabilize cellulose structure. AIM analysis aids study...
In the present work, bacterial cellulose (BC) was analyzed for its chromophore content with the chromophore release and identification (CRI) method. In aged BC, seven chromophores were unambiguously identified, despite their very low (ppb) presence. The compounds contain 2-hydroxy-[1,4]benzoquinone, 2-hydroxyacetophenone and 5,8-dihydroxy-naphthoquinone moieties. These three classes of key chromophores...
The X-ray diffraction-based Segal Crystallinity Index (CI) was calculated for simulated different sizes of crystallites for cellulose Iβ and II. The Mercury software was used, and different crystallite sizes were based on different input peak widths at half of the maximum peak intensity (pwhm). The two cellulose polymorphs, Iβ and II, gave different CIs despite having the same pwhm values and perfect...
Powder and fiber diffraction patterns were calculated for model cellulose crystallites with chains 20 glucose units long. Model sizes ranged from four chains to 169 chains, based on cellulose Iβ coordinates. They were subjected to various combinations of energy minimization and molecular dynamics (MD) in water. Disorder induced by MD and one or two layers of water had small effects on the relative...
Stable aqueous suspensions of cellulose nano-crystals (CNCs) were fabricated from both native and mercerized cotton fibers by sulfuric acid hydrolysis, followed by high-pressure homogenization. Fourier transform infrared spectrometry and wide-angle X-ray diffraction data showed that the fibers had been transformed from cellulose I (native) to cellulose II (mercerized) crystal structure, and these...
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