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Nanocelluloses were prepared from sugarcane bagasse celluloses by dynamic high pressure microfluidization (DHPM), aiming at achieving a homogeneous isolation through the controlling of shearing force and pressure within a microenvironment. In the DHPM process, the homogeneous cellulose solution passed through chambers at a higher pressure in fewer cycles, compared with the high pressure homogenization (HPH) process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) demonstrated that entangled network structures of celluloses were well dispersed in the microenvironment, which provided proper shearing forces and pressure to fracture the hydrogen bonds. Gel permeation chromatography (GPC), CP/MAS (13)C NMR and Fourier transform infrared spectroscopy (FT-IR) measurements suggested that intra-molecular hydrogen bonds were maintained. These nanocelluloses of smaller particle size, good dispersion and lower thermal stability will have great potential to be applied in electronics devices, electrochemistry, medicine, and package and printing industry., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Nanocellulose from sugarcane bagasse was isolated by high pressure homogenization in a homogeneous media. Pretreatment with an ionic liquid (1-butyl-3-methylimidazolium chloride ([Bmim]Cl)) was initially involved to dissolve the bagasse cellulose. Subsequently, the homogeneous solution was passed through a high pressure homogenizer without any clogging. The nanocellulose was obtained at 80 MPa for 30 cycles with recovery of 90% under the optimum refining condition. Nanocellulose had been characterized by Fourier transformed infrared spectra, X-ray diffraction, thermogravimetric analysis, rheological measurements and transmission electron microscopy. The results showed that nanocellulose was 10-20 nm in diameter, and presented lower thermal stability and crystallinity than the original cellulose. The developed nanocellulose would be a very versatile renewable material., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Highlights • Hydrogen bonds of cellulose might be cracked by two ways at different temperatures. • The O(3)H–O(5) bonds disruption could promote the dissolution at lower temperature. • The (O(2)H–O(6)) bonds might be responsible for dissolution at higher temperature. • Higher dissolving temperature might be a way to avoid cellulose degradation in ILs. Abstract Ionic liquids have been powerful solvents for cellulose. Mechanistic investigations of the dissolution processes have been extensively studied. In this paper, an experimental study has revealed that temperature also comes into play in cellulose dissolution. The supramolecular stuctrure of cellulose has been measured by X-ray diffraction, Fourier transform infrared spectroscopy, Solid-state CP/MAS 13C NMR, X-ray photoelectron spectroscopy and Gel permeation chromatography analysis, and the effects of temperature on hydrogen bonds of cellulose in ILs were investigated. These results indicated that hydrogen bonds of cellulose might be cracked by different ways at different temperature: The disruption of intramolecular hydrogen bonds (O(3) H-O (5)) could promote the dissolution process at lower temperature. And the disruption of intramolecular hydrogen bonds (O(2) H-O (6)) might be responsible for cellulose dissolution at higher temperature. It was suggested that higher dissolving temperature might be a way to avoid cellulose degradation with a high cellulose yield. [ABSTRACT FROM AUTHOR]

Nanocellulose from eucalyptus ( Eucalyptus robusta Smith ) pulp was extracted by simply disrupting the hydrogen bond network of celluloses with high pressure homogenization (HPH). It was found that nanocellulose was 20–100 nm in diameter, and presented a narrower molecular weight distribution, lower thermal stability and crystallinity index. Fourier transform infrared (FT-IR) and solid state cross polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13 C NMR) were used to confirm the physicochemical properties of nanocellulose, suggesting that intra-molecular hydrogen bonds are entirely maintained. Meanwhile, the feasibility of high pressure homogenization for different cellulosic biomass materials was investigated using comparison of eucalyptus pulp nanocellulose, sugarcane ( Saccharum officinarum ) bagasse nanocellulose and cotton ( Gossypium spp) nanocellulose. Results showed that eucalyptus pulp chains could be interrupted easily by the shearing forces for its harder texture, which was suited for high pressure homogenization. Other kinds of cellulose could also be well suited through controlling key parameters such as mechanical forces and treatment temperature in the process. [ABSTRACT FROM AUTHOR]

Abstract: A simple and sensitive colorimetric method for cysteine detection was established based on the carboxymethyl cellulose-functionalized gold nanoparticles (CMC-AuNPs). The nanoparticles were directly synthesized with sodium carboxymethyl cellulose by a simple approach, which would protect particles against salt-induced aggregation. Then the CMC-AuNPs solution exhibited a high colorimetric selectivity to cysteine. The assay results indicated that the introduction of cysteine could induce the aggregation of the colloidal solutions at the presence of sodium chloride, displaying changes in color and in UV–vis absorption spectra. Thus an exceptionally simple, rapid method for detecting cysteine was obtained at the linear range of 10.0–100.0μM with the relative coefficient of 0.997. The proposed method possessed the advantages of simplicity and sensitivity, and was applied to real urine sample detection. The results were satisfying and the proposed method was especially appropriate for detection of cysteine in biological samples. [Copyright &y& Elsevier]