Cellulose最新文献

This study introduces a sustainable and mechanically passive approach to producing cellulose micronised powder from hemp fibres using a choline chloride/lactic acid-based deep eutectic solvent (DES). The DES treatment disrupted the fibre matrix, improved surface purity, and enhanced cellulose crystallinity without relying on any mechanical grinding or milling stages. Characterisation through scanning electron microscopy (SEM), Atomic force microscopy (AFM), Fourier-transform infrared (FTIR) spectroscopy, Energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) confirmed superior structural uniformity and purity in the DES-treated samples compared to raw and conventionally bleached hemp. The particle size distribution revealed a significant reduction in median size, ranging from 8.4 to 39.5 µm. Crystallinity was markedly improved in treated samples, affirming the removal of lignin and hemicellulose. FTIR results confirmed the removal of non-cellulosic parts and esterification of cellulose, while EDX results further supported this outcome, with elemental profiles closely aligns with theoretical cellulose composition. Additionally, the DES system demonstrated excellent reusability over three cycles, maintaining high solvent recovery (> 92%) and consistent powder yield (78–91%), confirming its practical applicability. Overall, this work offers a green and scalable route for producing cellulose powder from hemp, with potential applications in polymer reinforcement, coatings, and other bio-based materials.

A new cellulose fiber extracted from Iris pallida Lam. (IPL) was examined for the first time as a potential reinforcement in composite materials. Morphological analysis was conducted using a scanning electron microscope, allowing for a detailed observation of the fiber ultrastructure. The fiber diameter was measured with an optical microscope, showing a variation ranging from 50 to 60 µm. The thermal properties were evaluated using differential scanning calorimetry (DSC), providing information on the thermal stability of the fiber. The chemical composition was determined by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Tensile tests were performed using a tensile testing machine to evaluate the fiber mechanical properties. The results revealed a crystallinity index of approximately 74.75% and an average crystallite size of 4.72 nm, indicating a relatively ordered nanoscale structure. The tensile strength measured for a single fiber with a length of 40 mm and a diameter of 54.5 µm was 683.03 ± 129.21 MPa, while the Young’s modulus was 21.07 ± 3.12 GPa and the strain was 3.24 ± 0.38%. These results demonstrate that IPL fibers possess advantageous mechanical and structural characteristics, making them promising as reinforcement in composites. The observed properties suggest that IPL fibers could enhance the performance of composite materials by offering an attractive combination of strength and flexibility.

Spherical calcium carbonate (CaCO₃) is widely used as a drug delivery vehicle, food additive, and filler because of its high biocompatibility, biodegradability, and non-toxicity. In particular, the regulation of CaCO₃ particle size enhances the reproducibility of functional properties and plays a critical role in ensuring consistent performance in various applications. However, their size-regulated, morphology-controlled, and eco-friendly preparation remains a challenge. Herein, we report the first successful attempt to provide a promising morphology-controlled fabrication strategy for cellulose nanofiber (CNF)-mediated mesoporous spherical CaCO₃ composite particles with tunable functionality using a scalable, environmentally friendly, 100% aqueous co-spray drying process. Sustainable microfibrillated CNFs with abundant surface hydroxy groups were employed as key 3D structural frameworks for the efficient construction of spherical CaCO₃ composite microparticles. During the spray-drying process, the CNFs facilitated the uniform adhesion of CaCO₃ nanoparticles to the cellulose network through electrostatic interactions. These cohesive interparticle interactions effectively prevented the indiscriminate aggregation of CaCO₃ nanoparticles, resulting in a consistent mesoporous spherical morphology. Furthermore, the morphology and size of the CNF-mediated composite particles were controlled by adjusting the co-spray drying process and material parameters, which influenced the size of the atomized droplets and the solvent evaporation rate during the subsequent drying phase. This green one-pot approach produced multifunctional CNF-mediated composite particles with improved oil and water repellency, high visible and near-infrared reflectance, and superior particle hardness compared to conventional CaCO₃ particles, demonstrating its versatility for the straightforward preparation of sustainable morphology-controllable particles with tunable functionality.

Paper-based analytical devices (PADs) have been widely considered a cost-effective and convenient solution for biosensing. The controlled functionalization of paper is a key requirement to implement sensitive, reproducible and robust PADs. The present work leverages an azetidinium bifunctional coupler for the modular grafting of chemical functionalities onto carboxymethyl cellulose (CMC), which can be used to easily incorporate functionality to paper sheets. Two approaches were developed: (i) CMC was first adsorbed onto paper and azetidinium derivatives were then grafted onto the carboxylate groups to confer the desired chemical functionality (i.e., alkyl, alkyne and azide), and (ii) the functionalities were first grafted onto CMC, which was then irreversibly adsorbed onto cellulose fibers. The modified CMC and paper sheets were characterized by NMR, FTIR, conductometric titration, and fluorescence microscopy. The degree of modification of the paper surfaces was quantitively assessed by reacting alkyne-bearing paper with FAM-azide and compared to paper surfaces where carboxylate groups were introduced through alternate routes. These experiments showed that grafting azetidinium derivatives onto CMC before or after adsorption onto cellulose fibers can introduce accessible reactive groups onto paper, albeit with different efficiency. As proof of concept for the introduction of biological functionalities onto paper, alkynylated biotin was reacted with paper functionalized with azide-CMC, followed by the specific binding of fluorescent streptavidin. The method developed to functionalize cellulosic materials via azetidinium derivatives is simple, cost-effective, versatile, and provides broad flexibility to graft a range of chemical and biological functionalities. We anticipate this method will aid in the development of value-added functional paper and PADs.

Oxidative stress plays a role in corneal epithelial disorders by inducing inflammation and apoptosis of corneal epithelial cells. Although the topical administration of conventional eye drops is the most commonly used treatment, their high dosing frequency may reduce patient adherence and therapeutic outcomes. In the study, we developed a nitric oxide (NO)-releasing hydrogel—GSNO-grafted carboxymethyl cellulose (CMC-GSNO)—as a sustained-release topical formulation for corneal wound healing. CMC-GSNO was synthesized by EDC/NHS crosslinking and nitrosation. The properties of CMC-GSNO synthesized using EDC/NHS activation for either 1 or 2 h were characterized by FTIR, ¹H NMR, Ellman’s assay, Griess assay, DPPH assay, SEM and in vitro drug release analysis. Both 1 h and 2 h activation conditions produced porous hydrogels with sustained NO release over 7 days, following first-order kinetics (R² > 0.92). The optimized formulation (1% CMC-GSNO (1.24)), with an NO concentration of 159 μM, showed no cytotoxicity in SIRC cells. In a post-treatment cellular model, 1% CMC-GSNO (1.24) was shown to reduce oxidative stress-induced damage in SIRC cells by downregulating inflammatory gene expression (TNF, IL-1α, IL-6, IL-8, MMP-3, and MMP-9), decreasing apoptosis, and enhancing cell viability. The ocular biocompatibility of 1% CMC-GSNO (1.24) was demonstrated in a rabbit model. These results suggest that CMC-GSNO is a promising NO-releasing hydrogel with sustained therapeutic activity and biocompatibility, offering potential as a topical ocular treatment for oxidative stress-related corneal disorders with reduced dosing frequency.

Cellulose nanofibres (CNFs) and graphene oxide (GO) are sustainable, high-performance materials widely explored for functional composites. In this study, an eco-friendly, scalable, surfactant and binder-free method was deployed to fabricate freestanding, porous CNF-GO films using doctor blade casting followed by freeze-drying. The effects of CNF and GO concentrations, along with film thickness, were studied to establish relationships between the process, microstructure and final properties. Rheological analysis showed shear-thinning behaviour, demonstrating that GO addition increased viscosity by at least 113%, enabling improved processability at lower CNF concentrations. Mechanical testing revealed that higher CNF content and film thickness improved tensile strength and Young’s modulus but also increased pressure drop, reducing air permeability. Incorporating 0.1 wt% GO reduced pressure drop by nearly 23% at a flow rate of 2 L/min for 4 wt% CNF films with 2 mm thickness, balancing mechanical strength and air permeability. Numerical analysis was also used to predict pressure drop as a function of structural parameters, validating experimental results. A formulation of 6 wt% CNF with 0.1 wt% GO at 1.5 mm thickness was identified for multifunctional performance. This study demonstrated a continuous, scalable route to fabricate mechanically robust, porous CNF-GO films with tunable properties, offering strong potential for applications in air filtration and lightweight structural materials.

Due to rising environmental concerns and the necessity to reduce the use of fossil-based resources, the development of fully/partially bio-based polymer composites have gained considerable attention. In this connection, an attempt has been made to develop partially bio-based vanillin-based polybenzoxazine-silica (PBZ-Si) hybrid nanocomposites by simple sol–gel approach for multifunctional applications, including oil–water/ oil–water emulsion separation, anti-icing, thermal, and corrosion resistance. The benzoxazine monomers (V-fa and V-sa) were prepared through Mannich reaction using vanillin (V), stearylamine (sa)/ or furfuryl amine (fa) and paraformaldehyde. The synthesized benzoxazines were confirmed by FT-IR, ¹H NMR, and DSC. To enhance the hydrophobic, and thermal properties of the neat PBZ, silica was introduced to develop PBZ-Si hybrids by an in-situ sol–gel approach using V-fa/ or V-sa, 3-aminopropyl triethoxysilane (3-APTES) and tetraethyl orthosilicate (TEOS) followed by thermal ring-opening polymerization. The incorporation of silica into PBZ hybrid composites enhanced the thermal stability, good oil–water/ oil–water emulsion separation and anti-corrosion properties. Notably, the PBZ-Si hybrid composites coated cellulose substrate showed a higher value of water contact angle of 156 ± 1° and achieved a high oil flux value of 27,283 Lm⁻² h⁻¹ and separation efficiency of 99.5% even after 20 cycles. The PBZ hybrid coated on cellulose substrate exhibited better separation ability even after the substrate was treated with adverse conditions, including acidic, basic, abrasion, and temperature. Further, the PBZ-Si hybrids coated on MS substrates revealed good corrosion-resistant behaviour with an inhibition efficiency of 96%. As research and development continue, these bio-based, sustainable PBZ hybrid materials may play a pivotal role in advancing separation technologies and corrosion-resistant applications.

In response to growing environmental concerns, plant fibers have emerged as sustainable, lightweight, and cost-effective alternatives to synthetic reinforcement materials. However, challenges such as moisture susceptibility, thermal instability, and interfacial incompatibility limit their performance and application. Atomistic studies provide fundamental insights into the molecular origins of these limitations, shedding light on the mechanical, thermal, and interfacial behavior of plant fibers. This review first introduces the multiscale architecture of plant fibers, followed by a detailed discussion of atomistic models developed to investigate their microstructural and mechanical properties. The review then explores the atomistic studies on moisture- and temperature-dependent conformational dynamics of cell wall components, including crystalline cellulose Iβ, amorphous cellulose, their interactions with amorphous matrix of hemicellulose and lignin as well as their impact on fiber performance. Finally, the molecular effects of surface modification strategies on interfacial adhesion, wettability, and mechanical reinforcement are analyzed to figure out the underlying mechanisms of performance enhancement. These atomistic insights bridge the gap between molecular mechanisms and macroscopic functionality, offering guidance for the design of high-performance, sustainable plant fiber composites.

In this study, a nanocomposite based on polyvinyl alcohol (PVA) incorporating cellulose nanowhiskers (CNWs) and glutaraldehyde (GA) was developed using a straightforward and effective cross-linking approach, demonstrating rapid water-induced shape memory and excellent mechanical characteristics. Microstructural analysis revealed good dispersion of CNWs within the PVA matrix. FTIR analysis indicated that the crosslinking mechanism involves both physical (via hydrogen bonding) interactions and chemical (via acetal bonding). The PVA-CNW nanocomposites displayed markedly improved mechanical properties, featuring a Young’s modulus of approximately 10.4 GPa and a tensile strength of approximately 219 MPa, attributed to the inherent mechanical properties of CNWs and the establishment of robust hydrogen bonding between PVA and CNW. Furthermore, the simultaneous introduction of CNWs and GA facilitated water-induced shape memory behavior, with a shape recovery ratio approaching 100% within 36 s. This heightened sensitivity can be ascribed to increased cross-linking between PVA-CNW and PVA-GA, serving as hard components to retain the permanent shape.

Fish oils with various physiological functions are prone to oxidation and have poor water dispersion, which greatly restricts their application in diversified food scenarios. In this work, the rigid rod-like cellulose nanocrystals (CNC) with large amounts of sulfate were prepared via sulfuric acid hydrolysis. Inspired by the flexible outer layer and rigid inner layer of coconut, we assembled cationic chitosan on the negatively charged CNC emulsion droplets to construct CNC/chitosan (CNC-CS) bilayer emulsions with the rigid inner layer and flexible outer layer. With increasing chitosan concentration, the droplet diameter of CNC-CS emulsions was reduced, accompanied by a narrower size distribution. Compared with the CNC emulsion, the droplet diameter of CNC-CS emulsion with the chitosan concentration of 0.9% (CNC-CS-0.9) decreased from 77.2 to 13.1 μm. Moreover, the storage and centrifugal stability of the emulsions increased with chitosan concentration. Surprisingly, the CNC-CS-0.9 emulsion exhibited excellent stability over the wide pH range (2–8), temperature range (25–90 °C) and ionic strength range (0–400 mmol/L), and three freeze–thaw cycles. Furthermore, compared with CNC emulsion, the CNC-CS-0.9 emulsion exhibited reductions of 11.9% and 23.7% in primary and secondary oxidation products, respectively, indicating that the rigid and flexible bilayer interface of CNC-CS emulsions can effectively delay the oxidation of fish oil. Therefore, this study proposes new strategies for the structural design of polysaccharide-based bilayer emulsions and the innovative construction of functional lipid protective armors.