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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. [ABSTRACT FROM AUTHOR]

Abstract: 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 80MPa 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 10–20nm in diameter, and presented lower thermal stability and crystallinity than the original cellulose. The developed nanocellulose would be a very versatile renewable material. [Copyright &y& Elsevier]

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]

• Carboxymethyl chitosan and pullulan exhibited good compatibility in the film matrix. • Galangal essential oil was successfully loaded in CMCS/Pul blend film. • The loading of 8 % GEO improved the preservation effect of blend films on mango. • CMCS/Pul-GEO blend films offered a potential alternative to synthetic materials. This study aimed to develop an active edible film based on carboxymethyl chitosan (CMCS) and pullulan (Pul) incorporated with galangal essential oil (GEO) by the casting method. And their physical properties, structural and preservation effect on mangoes were characterized. The CMCS/Pul ratio was determined to be 2.5:2.5 after the optimization of physical properties, mechanical properties and barrier properties of the blend film. The results of FT-IR and XRD showed that hydroxyl groups of Pul interacted with the carboxyl groups of CMCS and the blend films had good compatibility. Good thermal stability of CMCS/Pul-GEO films was further proven by TGA curves. The CMCS/Pul-8 %GEO film showed effective preservations on mango fruits during 15 days of storage at 25 ± 1 °C, based on the characterization by fruits weight loss, firmness, titratable acidity, soluble solids. Consequently, CMCS/Pul-GEO blend films may be a promising eco-friendly packaging material for the industrial application of fruit preservation. [ABSTRACT FROM AUTHOR]