• Skov Mclean posted an update 6 months ago

    Cellulose and its derivatives are widely explored for films and thickening of pharmaceutical solutions, in paints, as reinforcement in composites, among others. This versatility is due to advantages such as renewability, low cost, and environmental friendliness. When used in polymer composites, due to the hydrophilic character of the cellulose, surface chemical modification is highly recommended to improve its compatibility with the polymeric matrix. Hence, this paper presents a systematic review of chemically modified cellulose/epoxy resin composites focusing on the last five years. The investigation followed the PRISMA protocol that delivers a meticulous summary of all available primary research in response to a research question. After including/excluding steps, thirty-six studies were included in the review. The results were presented focusing on thermal, mechanical and dynamic-mechanical properties of the composites. In brief, this methodology helped identifying the main gaps in knowledge in that field.Quinacridone, a red pigment, is prone to aggregation, which results in undesirable color changes. Cellulose nanofibers (NFs) have been reported to adsorb quinacridone and suppress its aggregation. In this study, we investigated the potential of chitin and chitosan NFs which possess acetoamide and amino groups, as a quinacridone dispersant. Chitosan NFs, obtained by fibrillation using high-pressure homogenizer, adsorbed more quinacridone than cellulose NFs. SEM observations showed that chitosan NFs inhibited the aggregation of quinacridone, but chitin NFs did not. NMR analysis suggested the hydrogen bonding between chitosan NFs and quinacridone induced by the amino groups. The results indicated that the amino groups more facilitated the intermolecular interactions between NFs and quinacridone than the hydroxyl groups whereas the acetamide groups hindered them. Color measurements showed that the redness of quinacridone improved when cellulose or chitosan NFs were added. Chitosan NFs were found to be a novel candidate for quinacridone dispersants.Nanocellulose was isolated from okara using either ultrasound or high-pressure homogenization treatments. https://www.selleckchem.com/products/sumatriptan.html Dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, swelling behavior, rheological properties, and thermal analysis were used to characterize the physical-chemical and structural properties of the cellulose obtained. Sonication at 600 W for 15 min led to a cellulose material with a small mean particle diameter (d =0.22 μm), narrow polydispersity index (PDI = 0.21), strong negative charge (ζ = -36 mV), high swelling ratio (SR = 7.6), high crystallinity index (CI = 72 %), and formed viscous solutions. The initial pyrolysis temperature of the cellulose increased from 212 to 225 ℃, while the pyrolysis residue decreased from 26 to 12 %, after the sonication/homogenization treatment. The cellulose material produced in this study may be applied in various food and non-food applications as a texture modifier, stabilizer, structural component, or digestion modifier.It is still a big challenge to obtain hydrophobic thermoplastic starch with outstanding mechanical performance due to the inevitable usage of typical hydrophilic plasticizers like glycerol during processing. Herein, we report a novel hydrophobic thermoplastic starch using a supramolecularly induced thermoplasticization technique. To achieve this aim, a functional sucrose-based ionic liquid crystal (ILC) including numerous chloride atoms has been firstly synthesized, and the obtained ILC molecules are then used as supramolecular inducers to thermoplasticize corn starch granules. Thermoplasticity and hydrophobicity of the prepared supramolecularly induced thermoplastic starch (STPS) with different ILC contents have been extensively investigated. Mechanism of the supramolecularly induced thermoplasticization has been investigated using molecular simulation as well. The prepared STPS with the maximum tensile strength of 8.4 MPa and water contact angle of about 117° show large potential applications in green and sustainable packaging materials.Preparation of renewable, insoluble, and transparent films is still a major challenge for the application of soft electronics and packing industry. Herein, a “green” protocol for preparation of such a film based on carboxymethyl cellulose (CMC) is presented, where acid assistant freeze-thaw method was used in combination with drying. We have shown that the resultant films displayed flexibility, high light transmittance (above 90 %), insolubility, high mechanical performances (elastic modulus of 29.6 MPa), and good thermal stability. Moreover, CMC film/filter paper was fabricated, and the waterproof and mechanical properties of which were investigated. This approach offers a promising route to the fabrication of flexible and transparent films with good waterproof properties based on soluble biomass.Cellulose is a renewable, biodegradable, biocompatible, and sustainable material. A bamboo cellulose-based nanofiltration membrane (LBL-NF-CS/BCM) was prepared with a combination of layer-by-layer assembly and spraying methods. The chemical structure, morphology, and surface charge of the resultant LBL-NF-CS/BCM composite membranes were characterized based on Thermo Gravimetric Analysis (TGA), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy Scanning (XPS). The nanofiltration performance of the LBL-NF-CS/BCM composite membranes was evaluated using 500 ppm NaCl solutions under 0.3 MPa pressure. It was found that the LBL-NF-CS/BCM composite membranes had a rejection rate of about 36.11 % against a 500 ppm NaCl solution under the conditions tested, and membrane flux of about 12.08 L/(m2 h) was reached. The combined layer-by-layer assembly and spraying provides a scalable and convenient process concept for nanofiltration membrane fabrication.Normal and high amylose corn starches were modified using HMDSO plasma at different time treatments. Changes in functional properties of starch granule, film-forming solutions (FFS) and films were investigated. SEM analysis revealed HMDSO coating deposition on the granule surface, which limited the amylopectin leach out from the granules to the continuous matrix, affecting the rheological properties of the FFS. The amylopectin restriction resulted in a low reinforcement of the network decreasing the viscosity as indicated by n and k values. Also, a gel-like behavior (G’ > G″) was observed when the amylose and time treatment increased, suggesting that the matrix becomes less elastic with softer entanglement. This behavior was confirmed by creep test and Burger model parameters. The plasma treatments allowed obtaining FFS with low viscosity, suitable for developing soft and hydrophobic films with low flexibility, as indicated by the decrease of the maximum stress, Hencky strain and permeance values.

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