Cellulose最新文献

Spherical selenium nanoparticles (Se NPs) were synthesized by green chemical reduction method using biocompatible chitosan (CS) or as reported herein for the first time, cationic cellulose nanofibers (CCNFs) as stabilizers. CNFs were cationized using (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC), followed by high-pressure homogenization. The anionic demand of the CCNFs was found to be 2000 ± 2 µeq/g and the degree of substitution was 0.25 ± 0.01. The optimization of Se NP synthesis was done using response surface methodology with controlled composite design. Two response surface models were developed to optimize the size and stability of CS-Se NPs and CCNF-Se NPs. Concentrations of Na₂SeO₃, ascorbic acid, and CS or CCNFs were used as three variables, and their interaction was studied as a function of size and zeta potential. The results indicate that the variables fitted into the model and was validated using a combined contour plot of size and zeta potential. From the model, CS-Se NPs of size and zeta potential in the range between 10 and 70 nm and 30–40 mV were synthesized, while CCNF-Se NPs of size and zeta potential in the range between 50 and 85 nm and 30–35 mV were synthesized. EDX spectra confirmed elemental Se formation, and XRD pattern verified the presence of α-monoclinic Se crystallites. Additionally, the FTIR spectra confirmed the interaction between the stabilizing agent and Se NPs. Thus, CS- and CCNF-stabilized Se NPs were sustainably synthesized making them suitable for incorporation into CNFs and can be used as an active agent in food packaging application.

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In response to the growing demands for cotton fabric across different applications, the development of multifunctional fabric has garnered significant attention. However, it is still a great challenge to simultaneously realize functions such as flame retardancy, washing durability and water repellency of fabric. In this work, an eco-friendly multifunctional cotton fabric (CF-PZF/PDMS) with durable flame retardancy and superhydrophobicity was successfully prepared through nanotechnology and surface modification methods, which included the impregnation with phytic acid (PA), in-situ growth of zeolitic imidazolate framework-8 (ZIF-8) and spraying of polydimethylsiloxane (PDMS). Due to the synergistic effect of nitrogen, phosphorus and silicon elements, as well as the catalytic charring effect of transition metal (Zn²⁺) in ZIF-8 nanoparticles, CF-PZF/PDMS fabric had excellent flame retardancy and washing durability, with a limiting oxygen index (LOI) of 34.5% and a char length of 38 mm. Even after 20 washing cycles, CF-PZF/PDMS fabric still maintained an LOI value of 29.6%, exhibiting great self-extinguishing. Furthermore, the rough structure with hierarchical micro/nano-scale protuberances constructed by ZIF-8 and low surface energy of PDMS endowed CF-PZF/PDMS fabric with excellent superhydrophobicity and self-cleaning properties, evidenced by a water contact angle (WCA) of 152.8°. Notably, this fabric possessed excellent selective oil absorption capacity, high efficiency (more than 97%) in separating various oil–water mixtures, as well as superior stability in repetitive use. This study presents a straightforward method for fabricating multifunctional cotton fabric, which has promising applications in the field of advanced functional textiles and oil–water separation.

Graphical abstract

The materials characteristics of natural wood but also the properties of artificial cellulose/hemicellulose-based wood-inspired composite materials result from the molecular level organization and interactions between cellulose, hemicellulose, and lignin. Here, we use atomistic detail molecular dynamics simulations to examine the adsorption of model lignin-carbohydrate complexes (LCCs) consisting of a glucomannan polysaccharide chain with differing lignin fragment linkages to the crystalline facets of cellulose nanocrystals. The findings show that on crystalline cellulose surfaces exceeding in surface dimensions the length of the adsorbed hemicellulose chain, the LCCs can adopt orientations both parallel and perpendicular to the surface chains with response depending on the crystalline facet. The observation of perpendicular orientations is unexpected, as previous molecular level modelling studies systematically report parallel LCC adsorption orientation, however on cellulose interfaces modelling the narrow natural wood cellulose fibrils. Here, the perpendicular adsorption orientation is stabilized by extensive hydrogen bonding and adsorption of the hemicellulose chain with negligible chain bending. Overall, the results show that component dimensions (hemicellulose chain length vs cellulose crystalline surface dimensions) combined with understanding the differences of adsorption response at the difference crystal facets are crucial in understanding wood-inspired materials.

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Creating a textile with high thermal conductivity and unidirectional moisture conductivity is crucial for enhancing human comfort in terms of temperature and humidity during physical activity. However, it is difficult to improve the one-way transport index and thermal conductivity of the current hygroscopic-cooling fabrics. Here, we combined the superior qualities of cellulose fibers and chemical filament yarns to create a cool-feeling, extremely hygroscopic, green, and thermally conductive filament/bamboo core yarn. Cool polyester (CPET), polyethylene (PE), and cool nylon (CPA) were selected as the cores, and bamboo viscose fiber staple yarn was used as the skin layer to create three kinds of high moisture absorption and conductivity filament/bamboo core yarns. With filament/bamboo core yarn as warp yarn and cool filament as weft yarn, 9 kinds of Janus hygroscopic-cooling fabrics (J-HCFs) were prepared by simple weaving method. When the inner layer was PE and the outer layer was CPET/bamboo core yarn, J-HCF had excellent thermal-moisture management ability, including a desired one-way transport index (673.1%), a fast evaporation rate (1.839 mL/h), a high thermal conductivity (0.0915 W/mk), and a sense of contact coolness (Q_max of 0.295 W/cm²). In this paper, we provide a new method to develop environment-friendly thermal-moisture comfort fabrics. The J-HCF with directional water transmission and high thermal conductivity can be used to reduce the heat load of sportswear, summer clothes, medical fabrics and work clothes.

This study presents a sustainable approach to enhance cotton fabrics with multifunctional properties by in-situ functionalization using polydopamine (PDA) coating followed by the deposition of silver nanoparticles (AgNPs) through a self-reduction process. Polydopamine was chosen for its excellent adhesive and reductive properties, facilitating the uniform attachment of silver nanoparticles on the fabric surface. The functionalized fabrics were thoroughly characterized using FTIR, Raman spectroscopy, SEM, EDS, TGA, contact angle measurements, and XRD, confirming the successful integration of PDA and AgNPs. The modified cotton fabrics demonstrated 100% antibacterial activity against Staphylococcus aureus and achieved a water contact angle of approximately 131°, indicating enhanced hydrophobicity. Thermal stability was also improved, with a 15% increase in ash content at 600 °C. This dual-functional coating approach provides an effective means to develop antibacterial, water-resistant, and thermally more stable textile materials, offering potential applications in protective clothing, and other functional fabric domains.

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In recent years, adaptive thermal-moisture management textiles, which are commonly used as sports and leisure clothing materials, have attracted attention for enabling dynamic comfort and considering sustainability components with the advantages of multifunctionality, energy saving, and low chemical consumption. Thus, temperature-moisture dual-responsive shape memory materials changing features according to the multiple stimuli of the ambient environment and body microenvironments can be used for developing passive smart textiles. Herein, a temperature-moisture responsive shape memory nanocomposite finishing material based on temperature-responsive polyurethane and hydrophilic cellulose nanowhisker particles was applied to regenerated cellulosic knitted fabrics (cotton, recycled cotton, viscose, modal, lyocell, bamboo) by using an eco-friendly process. The minimum polymer concentration sufficient for the required dynamic breathability and absorbency properties was determined with optimization, considering an acceptable fabric hand. In addition to a realistic and comprehensive test plan for adaptive permeability and liquid transfer/absorption characteristics, morphological, chemical, physical, mechanical, and washing fastness of the treated fabrics were determined. According to the results, nanocomposite-treated fabrics, especially modal, and viscose not only exhibited adaptive breathability, sweat absorption, and transfer capability but also acceptable bending rigidity and higher mechanical properties. The mentioned results make these fabrics good candidates for inner layers of various sports and protective clothing that enable dryness, hence comfort under different conditions.

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Efficacious dosage of conventional hyperpigmentation treatments is limited by their toxicity and undesirable side effects. Bacterial cellulose (BC) patch containing plant phenolic  compound is proposed as an effective yet safe alternative. In this work, curcumin-loaded BC film (Cur(BC)) was developed as a cytocompatible inhibitor of in vitro melanogenesis in hyperpigmented melanocytes. (Cur)BC was characterized to understand its morphological, physical, and chemical properties. Its anti-melanogenic effects were assessed by in vitro studies performed on putrescine induced human epidermal melanocytes. Results show that Cur(BC) is non-cytotoxic, decreases melanin production by up to 58%, and down-regulates melanogenesis-related genes TYR, TRP-1, TRP-2. This report features the first evaluation of the synergistic effects and limitations of curcumin-loaded bacterial cellulose composites on melanin production in vitro.

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Cellulose ethers represent a class of water-soluble polymers widely utilized across diverse sectors, spanning from healthcare to the construction industry. This experimental study specifically delves into aqueous solutions of carboxymethylcellulose (CMC), a polymer that undergoes gel formation in acidic environments due to attractive interactions between hydrophobic patches along its molecular chain. We use rheometry to determine the linear viscoelastic properties of both CMC solutions and acid-induced gels at various temperatures. Then, applying the time-temperature superposition principle, we construct master curves for the viscoelastic spectra, effectively described by fractional models. The horizontal shift factors exhibit an Arrhenius-like temperature dependence, allowing us to extract activation energies compatible with hydrophobic interactions. Furthermore, we show that acid-induced CMC gels are physical gels that display a reversible yielding transition under external shear. In particular, we discuss the influence of pH on the non-linear viscoelastic response under large-amplitude oscillatory shear. Overall, our results offer a comprehensive description of the linear and non-linear rheological properties of a compelling case of physical hydrogel involving hydrophobic interactions.

TEMPO-mediated oxidation is the most popular approach to extracting carboxylated cellulose nanofibers (CNFs) from cellulose fibers (pulps). In this study, we have demonstrated the modified TEMPO/NaBr/NaClO oxidation method to extract CNFs from virgin (untreated) jute fibers which were not undergone any pretreatment process (e.g., delignification and pulping) before introducing the TEMPO-oxidation process. This one-pot approach combines the steps of delignification/pulping and cellulose oxidation. Three CNFs with different degrees of oxidation (carboxylate content of 1.18, 0.175, and 0.131 mmol/g) were prepared by the addition of varying amounts of NaClO (i.e., 48, 32, and 24 mmol/g, respectively), where the content of NaClO was found to affect the delignification efficiency of raw fibers. In specific, CNF (0.131 mmol/g) possessed residual lignin of 2% and hemicellulose of 2.5%; CNF (0.175 mmol/g and 1.18 mmol/g) retained lignin of 1.9% and hemicellulose of 2.3%. The results indicate that using excess NaClO could lead to the generation of nitroxonium ions, which selectively oxidize the hydroxyl groups in cellulose, hemicellulose, and lignin. As a result, the excess usage of NaClO (32–48 mmol/g) during the TEMPO/NaBr/NaClO process was more effective in delignification and hemicellulose removal. FTIR, ¹³C CPMAS-NMR, WAXD, contact angle, AFM, TEM, and BET techniques were used to characterize all extracted CNFs. All CNFs showed an average L of 1000 nm and a width of 6 nm.

This paper reports a facile and efficient process for the synthesis of furfuryl alcohol (FAL) from xylan in an isopropanol/MSH (CaCl₂·4H₂O) biphasic system. The conversion of xylan reached over 99.9%, with a FAL yield of 62 mol% at 150 °C for 2 h. Notably, isopropanol served dual roles as both the hydrogen donor and the organic phase, playing a pivotal role in the extraction and preservation of FAL. Additionally, self-prepared MSH was employed as the aqueous phase, concurrently functioning as a solvent and catalyst. Remarkably, the product distribution (furfuryl alcohol, levulinic acid, and γ-valerolactone) could be effectively modulated by adjusting the reaction time. Furthermore, the mechanism of FAL production from xylan revealed that FAL was obtained via the xylose-xylitol-furfuryl alcohol route, rather than the xylose-furfural-furfuryl alcohol pathway. The catalyst could be recovered through simple procedures, maintaining a FAL yield of approximately 60 mol% after three cycles of recovery, thereby laying the foundation for the facile and efficient industrial production of FAL from lignocellulosic biomass.