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The use of nano- or microfibrillar cellulose (NFC or MFC) in papermaking is generally hampered by high cost and potentially wasteful use in typical wet end applications. The solubility and fines nature of the material makes it inefficient to retain, and when retained it is generally inefficiently applied within the spatial distribution of the paper fibre matrix. To illustrate the benefits of capturing...
Cellulose mixed esters containing alkylphosphonate and carboxylate groups were prepared homogeneously by a new one-pot method using n-propyl phosphonic acid anhydride (T3P®) in LiCl/N-methyl-2-pyrrolidone (NMP). n-Propyl phosphonic acid anhydride acts as both an activating agent for carboxylic acids and phosphonation reagent. Cellulose mixed esters with DSacyl ranging from 1.4 to 1.8, and DSphos up...
Four different cellulose nanofibers samples were prepared from northern bleached softwood kraft fibers. Fiber diameter distributions were measured from SEM images. Fiber aspect ratios ranging from 84 to 146 were estimated from fiber suspension sedimentation measurements. Three samples had heterogeneous distributions of fiber diameters, while one sample was more homogeneous. Sheet forming experiments...
Novel utilization of cotton cellulose was developed by chemically modifying with concentrated sulfuric acid to prepare a novel kind of adsorption gel for gold. The adsorption behaviors of the gel were investigated for various metals from acidic chloride media. The gel was found to be highly selective for Au(III) over other precious and base metals tested over the whole concentration range of hydrochloric...
Suitable α-cellulose and cellulose II powders for use in the pharmaceutical industry can be derived from maize cob. α-Cellulose was extracted from an agricultural residue (maize cobs) using a non-dissolving method based on inorganic substances. Modification of this α-cellulose was carried out by its dissolution in the ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), and subsequent regeneration...
Cultivation of sisal, a plant with a short growth cycle, is highly productive in Brazil. This work is part of extensive research in which sisal is valued. In these studies, sisal fibers are used in the preparation of bio-based composites and in the derivatization of the pulp, including posterior preparation of films. This study aimed to examine the use of sisal pulp in the production of bioethanol,...
In the present study the effect of relative humidity (RH) during spin-coating process on the structural characteristics of cellulose acetate (CA), cellulose acetate phthalate (C-A-P), cellulose acetate butyrate (CAB) and carboxymethyl cellulose acetate butyrate (CMCAB) films was investigated by means of atomic force microscopy (AFM), ellipsometry and contact angle measurements. All polymer solutions...
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...
A softwood bleached kraft pulp (SBKP) and cotton lint cellulose were fully or partially mercerized, and these along with celluloses and commercially available regenerated cellulose fiber and beads were oxidized by 4-acetamido-TEMPO/NaClO/NaClO2 at 60 °C and pH 4.8. Weight recovery ratios and carboxylate contents of the oxidized celluloses were 65–80% and 1.8–2.2 mmol g−1, respectively. Transparent...
Recently-discovered lignocellulosic solvent, 8%(w/w) lithium chloride/dimethyl sulfoxide (LiCl/DMSO), was found to dissolve cellulose of varied crystal forms and degree of polymerization. Cellulose samples could be activated for dissolution by complexation with ethylenediamine (EDA), giving EDA contents of 20–23% (w/w) in the complex irrespective of the cellulose type. The cellulose solution gave...
The stabilizing role of carboxymethyl groups on the conformal deposition of Ag NPs over cellulosic fibers was elucidated while developing a method for the deposition of silver nanoparticles (NPs) on cellulose acetate (CA), cellulose and partially carboxymethylated cellulose (CMC) electrospun fibers. CMC fibers were prepared through judicious anionization of deacetylated cellulose acetate fibers. Ag...
In order to model the adsorption of xylan on cellulose, we have simulated, at the atomic level, the gas phase adsorption of small xylan fragments having 5 skeletal β (1 → 4) xylosyl residues (X5), using molecular dynamics simulations. A first regime was considered, corresponding to a low surface coverage, with the adsorption of isolated X5 in various initial orientations. In this regime, the simulation...
Chemical reactions in charged nanopores, such as present in cellulose fibers, can be accelerated by adding an inert salt, that does not participate in the reaction. Due to a Donnan-like equilibrium between ions inside and outside the pores, the concentration of co-ions in the nanopores (having a charge of the same sign as that of the pore wall), is lower than the concentration in the bulk. The co-ion...
The chemical structure of rye arabinoxylan (rAX) was systematically modified, exploiting selective enzymes to mimic different naturally occurring xylans, i.e., its degree of substitution (DS) was decreased using α-l-arabinofuranosidase, and a controlled decrease in the degree of polymerization (DP) was performed using endo-1,4-β-d-xylanase. The arabinose to xylose ratio was decreased from 0.45 to...
The meaning of the Ekenstam equation (1/DP − 1/DP°) = kt is shortly discussed. Several misleading statements about its application to cellulose hydrolysis are underlined in order to improve the reliability of kinetic analyses. To this end, some further simple analyses are suggested to the experimentalists.
Primary aliphatic amines were introduced into most of (>95%) carboxyl groups densely present on the TEMPO-oxidized cellulose nanofibril (TOCN) surfaces via carboxyl/amine salt formation in a water-isopropyl alcohol mixture. The carbon number of alkyl chain lengths introduced into TOCN varied using n-decyl-, n-dodecyl, n-tetradecyl-, n-hexadecyl- and n-octadecyl-amines. When n-dodecyl-, n-tetradecyl-...
A novel type of sponge-like material for the separation of mixed oil and water liquids has been prepared by the vapour deposition of hydrophobic silanes on ultra-porous nanocellulose aerogels. To achieve this, a highly porous (>99%) nanocellulose aerogel with high structural flexibility and robustness is first formed by freeze-drying an aqueous dispersion of the nanocellulose. The density, pore...
Lysozyme was attached through an amide linkage between some of the protein’s aspartate and glutamate residues to amino-glycine-cellulose, which was prepared by esterification of glycine to preparations of cotton nanocrystals. The nanocrystalline preparations were produced through acid hydrolysis and mechanical breakage of the cotton fibers from a scoured and bleached cotton fabric and a scoured and...
The current paper reports on an investigation of the kinetics of chitosan deacetylation by chitin deacetylase isolated from Absidia orchidis vel coerulea. The reaction rate was correlated with the concentration of GlcNHAc units of the polymer. It is shown that the process follows the Michaelis–Menten mechanism. Modification of the Michaelis–Menten equation by introducing the activity of the enzyme...
Oxidized nanocellulose (ONC) have been synthesized and grafted with tryptophan-based peptides of varying lengths using a two step coupling method. The ONC was first activated by N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide hydrochloride, forming a stable active ester in the presence of N-hydroxysuccinimide. Then, the active ester was reacted with the amino groups of the peptide forming an amide...
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