Cellulose最新文献

Chitosan modification is crucial for advancing biomedical applications. This study discusses the fabrication and characterization of new chitosan bead derivatives. The new hydrogel CSE was synthesized by reacting chitosan beads with epichlorohydrin which was further modified with isonicotinic acid hydrazide (INH) using microwave irradiation to produce CSEH hydrogel. The nanohydrogel NCSEH was fabricated by reacting CSEH with sodium tripolyphosphate (TPP) via ionic gelation technique. In addition, CSEH hydrogel loaded Ag and ZnO nanoparticles to give the nanocomposites CSEH-Ag NPs and CSEH-ZnO NPs respectively. The new chitosan bead derivatives were characterized using various instrumental analysis techniques including elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA), and Energy Dispersive X-ray Spectroscopy (EDX). The nanohydrogel NCSEH showed the highest thermal stability. TEM analyses confirmed the nano-scale dimensions of NCSEH, CSEH-Ag NPs, and CSEH-ZnO NPs with particle sizes ranging from 4.46 to 125 nm. EDX and SEM profiles of the modified CSEH-Ag NPs and CSEH-ZnO NPs showed distinct signals for Ag and Zn atoms, respectively. Elemental analysis revealed 0.36% silver for CSEH-Ag NPs and 5.90% zinc for CSEH-ZnO NPs confirming the successful formation of the nanocomposites. The anticancer activity of the new chitosan bead derivatives CSEH, NCSEH, CSEH-Ag NPs, and CSEH-ZnO NPs were evaluated against A-549 lung and HCT-116 colon cancer cell lines. The CSEH-ZnO nanocomposite demonstrated the most potent cytotoxic effect, exhibiting (IC₅₀) values of 36 ± 1.29 µg/mL against lung cancer cells and 24.99 ± 0.83 µg/mL against colon cancer cells. At concentration 500 μg/mL of CSEH-ZnO nanocomposite demonstrated the highest cell growth inhibition 97.14%, and 98.63% for lung and colon cells respectively. These results suggest that CSEH-ZnO nanocomposite is a promising candidate for targeted cancer therapy.

The emergence of nanomaterials is groundbreaking based on their performance that is inconceivable by conventional materials. Among these, nanocellulose stands out as a biodegradable nanomaterial derived from renewable plant sources. At the nanoscale, cellulose exhibits exceptional properties, largely due to its unprecedented surface area-to-volume ratio. Lignocellulosic fibers, sourced from traditional fiber plants or agro-residual biomass, provide a vast raw material base for nanocellulose production. In this study, okra and hemp plants were subjected to nanocellulose extraction processes. Via biological degumming, bast and fruit fibers were separated from okra plants and bast fibers from hemp plants, exposing the woody stem cores. The bast, fruit, and stem core fibers were cleaned from non-cellulosic components by use of an environmentally-friendly chlorine-free procedure. The isolated cellulose was subsequently broken into nanocrystals through acidic hydrolysis. The effects of the applied treatments on fibers’ morphological, chemical, crystal, and thermal properties have been investigated. FT-IR and SEM analyses indicated substantial removal of lignin, hemicelluloses, and waxes; whereas XRD diffractograms revealed partial conversion of cellulose Iβ to cellulose II during cellulose isolation processes. At the end of the isolation stage, fiber diameters dropped to 24.42—54.88 microns, and 77.48% to 90.11% crystallinity indices were attained. The yield of nanocellulose production processes was found to be 14.36% and 20.36% based on okra and hemp bast fiber mass, respectively. FESEM images revealed partial conversion to nanocellulose. Cellulose nanocrystals obtained from okra bast and hemp bast fibers displayed similar ribbon/rod structures with diameters in the range of 20–50 nm and lengths between 200–500 nm, while their crystallinity indices were between 61.63% and 70.78%, respectively. This study demonstrates the feasibility of nanocellulose production from okra bast and hemp bast fibers by use of a chlorine-free chemical process series.

Lignin-containing microfibrillated cellulose (LMFC) has shown great potential for improving paper strength; however, its application under industrial conditions remains underexplored. This study investigates the effect of mechanically produced LMFC on paper properties in the presence of industrial white-water and examines how varying chitosan amounts can modify white-water properties to further improve these properties. The addition of 3% (w/w) LMFC increased tensile index by 15%, elongation at break by 17%, tear index by 3.8%, and internal bonding strength by 9%. These improvements were enhanced with the addition of chitosan to the white-water at varying amounts (22.5, 27.5 and 32.5 mg/L), which increased the retention of LMFC, and other fine components present in the white-water. Additionally, chitosan enhanced the retention of colored compounds within the fiber matrix, a desirable outcome for packaging grades requiring specific color characteristics. These findings suggest that combining LMFC with chitosan-treated white-water can effectively enhance the mechanical properties of paper, making it suitable for industrial applications that demand high-strength performance, such as packaging.

Maintaining physiological thermoregulation homeostasis under extreme cold environments is critically imperative for human survival and functionality. However, traditional thermal management textiles face multifaceted challenges including limited insulation methods, unsatisfactory thermal efficiency, and narrow applicability across complex scenarios. Herein, a well-constructed advanced fabric is fabricated via layer-by-layer (LBL) self-assembly of carbon nanotubes (CNTs) and polydopamine (PDA) with an integrated design that synergistically combines high-efficiency photothermal conversion, Joule heating, superhydrophobic self-cleaning, and UV shielding properties. The CNT-PDA hierarchical design enables broadband solar energy harvesting (97% absorbance) and high photothermal efficiency for passive thermal management through solar energy. The synergistic combination of PDA's adhesive properties and LBL self-assembly techniques facilitates the construction of the 3D conductive network of CNTs with enhanced electrical conductivity (273.96 S/m), achieving wide-range temperature modulation (ambient to 100 °C+) via low-voltage-driven Joule heating for personalized active thermal management. The dual-energy strategy combining passive and active thermal management effectively addresses diverse thermal regulation requirements for body warming in extreme cold environments, ensuring all-day performance. Furthermore, the addition of methyltrimethoxysilane (MTMS) endows the fabric with hydrophobicity (water contact angle = 147.2°) and self-cleaning capability, enhancing its reliability under the extreme conditions of rain and snow in cold environments. Moreover, advanced fabrics exhibit low transmittance (4%) in the ultraviolet spectrum, providing effective ultraviolet protection in high-altitude, cold regions where ultraviolet radiation is particularly intense. This multifunctional advanced fabric with the simple preparation technique and outstanding overall performance provides promising applications for next-generation all-day personalized thermal wearables in extreme cold environments.

The understanding of the interactions between cellulose and ionic liquids are the foundation for the development of new processes, to explore new reactions and to establish a circular bioeconomy. The main problem is that direct measurement, from both quantitative and qualitative point of view is challenging. While there are methods to assess solution strength and wettability of ionic liquids with cellulose materials, the main challenge lies in the combination of a solid substrate and an applied liquid, limiting the number of accessible methods. We demonstrate in this paper that an in-situ solid-state NMR spectroscopical approach is capable of monitoring in real-time the mobility of ionic liquids in cellulose-based substrates. Specifically, we employ ¹H → ¹³C cross polarization magic angle spinning (CP MAS) NMR spectroscopy to examine mobility changes over varying exposure times in paper samples treated with ionic liquids. Through this approach, we capture the temporal evolution of IL signals, which in turn provide insights into mobility changes of ILs and also allow for identifying changes in cellulose crystallinity. The approach allows for a simple, semiquantitative assessment of cellulose solubility in ionic liquids and is in principle applicable to other biomass materials as well.

Cellulose nanofibrils (CNFs) offer impressive barriers against oil, grease, and gas when applied as a layer on paper or as a standalone film; however, coating CNFs onto paper with conventional equipment at useful coat weights in a single step is not currently possible. Here, we present a method to coat CNFs onto paper using an easily scalable vacuum-assisted approach which removes the water-rich layer that forms at the interface during the coating process. With the water layer removed, coat weights of 12–28 g CNFs/m² are achievable in a single step, depending on parameters including vacuum strength and initial cellulose concentration. The CNF-coated paper was found to nearly eliminate air permeability, reduce water uptake, and provide a high degree of resistance to oil, even after folding. This work opens the door for industrial-scale manufacture of CNF coated paper that can displace plastics in some food packaging applications.

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Cellulosic paper, a renewable-based and biodegradable material, is used in various applications, such as writing, filtration, packaging, and insulation. The impact of environmentally friendly coatings on enhancing the mechanical properties of ultrathin specialty paper was investigated in this study. The coatings, composed of organic/inorganic composites representing eco-friendly substances, include silica, which is introduced in an aqueous sol–gel process catalyzed by citric acid and sodium hydroxide, providing a “greener” alternative to traditional methods. TEOS (tetraethyl orthosilicate) sols and TEOS composites enriched with polysaccharides, such as micro-fibrillated cellulose (MFC), cellulose nanofibers (CNF), starch, and alginate, were explored as coatings to tune the paper’s mechanical properties. The coatings were applied by spray-coating, significantly enhancing tensile and flexural strength. TEOS/starch and TEOS/alginate coatings improved the tensile strength from 15 to 31 and 29 MPa, respectively. In contrast, the application of alginate resulted in slightly stiffer papers, and starch in more ductile ones. The flexural strength was notably increased with TEOS/alginate and TEOS/alginate/CNF coatings, from 8 to 15 and 14 MPa, respectively. Mechanical properties normalized to the added coatings’ solid content revealed that the TEOS sol was the most effective approach to boost both parameters. Coated papers showed improved resistance to water and abrasion compared to the reference material. Their surface morphology was analyzed using SEM, and silica/polysaccharide networks were examined with ²⁹Si NMR spectroscopy. Gelation points were determined by UV/Vis spectrophotometry, and TGA and contact angle measurements showed no significant impact on the related paper properties. These findings demonstrate the potential of TEOS sol and composites to tune and enhance the mechanical performance of ultrathin specialty papers.

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Lignocellulosic biomass (LCB), such as agricultural residue rich in cellulose and hemicellulose, can serve as a feedstock for bioethanol production due to its environmental benefits. Deep eutectic solvents (DES) are low-cost and greener solvents for LCB pretreatment. The present study investigated the efficiency of two DES types for rice straw pretreatment under microwave conditions: choline chloride:glycerol (ChCl:Gly) and choline chloride:formic acid (ChCl:FA). DES pretreatment was performed under microwave conditions (100–140 °C and 5–15 min) at 10% solids loading and constant power 200W. After pretreatment, the samples were characterized, and enzymatic digestibility was investigated at 50 °C for 72 h using enzyme loading of 6 filter paper unit g⁻¹ cellulose and 10% solids loading. Untreated rice straw consists of cellulose (41.8%), hemicellulose (24.9%), lignin (17.0%) and ash (15.0%). The cellulose content increased to 59.8% and 59.2% after ChCl:Gly and ChCl:FA pretreatment, respectively, while hemicellulose decreased to 15.6% and 10.1% after ChCl:Gly and ChCl:FA pretreatment, respectively. Lignin content decreased to 8.2% after ChCl:Gly pretreatment compared to 9.6% after ChCl:FA pretreatment. Ash content (20.4%) obtained after ChCl:FA pretreatment was higher than 14.0% obtained after ChCl:Gly pretreatment. The cellulosic and hemicellulose fractions from ChCl:Gly pretreatment were effectively hydrolyzed with glucose and xylose yield of 86.0% and 68.4%, respectively, compared to glucose and xylose yield of 58.2% and 62.8%, after ChCl:FA pretreatment. ChCl:Gly pretreatment enriched cellulosic content and preserved hemicellulose fraction, achieving a higher yield of fermentable sugars than ChCl:FA pretreatment; hence, it can potentially support a biorefinery.

This work presents an eco-friendly strategy for producing recyclable functional textiles by minimizing the use of hazardous chemical to promote safer and more sustainable applications for both indoor and outdoor use. Exfoliated g-C₃N₄ (TGCN), obtained through thermal treatment of bulk g-C₃N₄ (BGCN), was uniformly coated on viscose fabric via ultrasonic-coating, ensuring photocatalytic functionality. Both BGCN and TGCN were immobilized onto the surface of viscose fabric, denoted as BGCN-coated and TGCN-coated, respectively. The photocatalytic performance of the coated viscose fabric was examined through the photodegradation of Rhodamine B (RhB) dye and photocatalytic antibacterial test against Gram-negative Escherichia coli (E. coli) under visible light irradiation. Remarkably, TGCN-coated achieved complete removal of RhB dye with 23.59% of TOC removal within 150 min, outperforming the BGCN-coated. Both coated textiles exhibited excellent antibacterial performance, yielding 99.0% elimination of E. coli within 150 min. TGCN-coated exhibited better self-cleaning ability than BGCN-coated, as evidenced by its faster and more effective coffee stain decolorization under light irradiation. The superior photocatalytic performance of TGCN-coated was attributed to the increased specific surface area of TGCN (26.9554 m²/g) which was three times larger than that of BGCN (7.2942 m²/g) upon thermal exfoliation. This enhancement exposed more active sites on the photocatalyst surface, resulting in the generation of more reactive radical species during photocatalysis. Despite a relatively wider band gap of TGCN (2.81 eV) compared to that of BGCN (2.76 eV), its lower recombination rate of electron–hole pairs with decay lifetime of 4.94 ns enhanced the photocatalytic efficiency. Moreover, TGCN-coated exhibited high durability and stability by retaining over 95% of antibacterial efficiency after 10 washing cycles.