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To develop special insulating paper is of great significance to promote the service life of transformers. Using molecular simulation to guide the development of special insulating paper can greatly reduce the trial-and-error rate and waste of resources in traditional experiments. The effect of different types of polysilsesquioxane (POSS) on cellulose insulating paper was investigated by using molecular simulation. This paper investigated the thermal stability and mechanical properties and electrical characteristics of caged POSS, semi-caged POSS, and ladder-like POSS doped cellulose insulating paper. The results show that POSS with all types can enhance the performance of cellulose insulating paper, and ladder-like POSS possess the best modification effect. The glass transition temperature was increased by 58 K, and the bulk modulus, shear modulus, and elastic modulus of cellulose insulating paper doped with ladder-like POSS can improve up to 27.07%, 45.67%, and 41.28%, respectively. Meanwhile, the dielectric properties of ladder-like POSS modified insulating paper are also significantly improved. The findings of this paper propose a method for the preparation of ladder-like POSS modified insulating paper, which provides theoretical guidance for the experimental preparation of special insulating paper. [ABSTRACT FROM AUTHOR]

We report on the studies of conduction mechanism, direct current conductance, and 1 f -noise of cellulose nanofiber (CNF) and multiwalled carbon nanotube (MWCNT) composites. The composites were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The temperature- and voltage-dependence of the dc conductance Σ were, respectively, probed to investigate the charge transport mechanism and the electrical response of the composite. At room temperature, the increase in Σ with wt. % of MWCNT ϕ showed typical percolation behavior. The Σ − T behavior was fitted to the combination of one-dimensional variable range hopping and the fluctuation-induced tunneling, which were attributed to hopping of charge carriers through 1D MWCNTs and the tunneling of charge carriers between the bundles of MWCNTs, respectively. The non-Ohmic electrical conduction was characterized by the onset voltage V 0 (T) which scaled with Ohmic conductance Σ 0 as V 0 (T) ∼ Σ 0 (T) x T , with x T being the onset exponent increased with ϕ. A scaling description based on the data collapse method was adopted to find the parameters V 0 (T) and x T. The noise power spectrum S V (f) followed the relation S V (f) ∼ V β with two different power-laws: β 1 in the Ohmic and β 2 in the non-Ohmic region (β 1 > --> β 2). Interestingly, this change in power-laws occurs at the same V 0 (T) obtained from Σ − V curves. A simple model was proposed to explain the noise behavior after V 0 (T). It is expected that such electrical characterization of CNF-MWCNT nanopaper composite would open up their possibility of application in flexible electronic devices, intelligent networks, sensors, and actuators. [ABSTRACT FROM AUTHOR]

Using Onsager–Straley's second-virial theory, we investigate the cholesteric pitch of cellulose nanocrystal (CNC) suspensions. We model the CNCs as hard chiral bundles of microfibrils and examine the effect of the shape of these chiral bundles, characterized by aspect ratio and chirality, on the cholesteric pitch. Additionally, we explore the impact of length polydispersity and surface charge on the cholesteric phase of CNCs. Furthermore, we consider binary mixtures of twisted bundles and achiral primary crystallites to provide a more realistic representation of CNC suspensions. Our findings reveal that the degree of bundle twisting significantly affects the helical twisting of the cholesteric phase. We also observe that the average particle length and length polydispersity have substantial effects on strongly twisted bundles but minimal effects on weakly twisted ones. Finally, our study indicates that as the range of electrostatic interactions increases, the transfer of chirality from the microscopic to macroscopic length scales becomes masked, resulting in an increase in the cholesteric pitch. In the case of binary mixtures, the bundles act as chiral dopants, and an increasing fraction of bundles progressively enhances the helical twisting of the cholesteric phase. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate the patient's morbidity and postsurgical complications after treatment of palatal donor sites after free gingival graft harvesting using leucocyte- and platelet-rich fibrin (L-PRF) membranes or a hemostatic agent with oxidized and regenerated cellulose. Method and materials: Forty-two palatal donor sites after free gingival graft harvesting in 42 patients were randomly assigned to experimental (L-PRF membrane) or control procedure (hemostatic agent). The primary outcome was postoperative pain related to the wound located at the palatal area, and the secondary outcomes were postoperative discomfort, inability to chew, postoperative stress, surgical chair time, thickness of the palatal fibromucosa, and thickness of the free gingival graft. The patient-reported outcome measures were recorded after 1 week. Results: After 1 week, a statistically significant difference was found between groups in terms of postoperative stress (P = .008). No statistically significant differences in terms of postoperative pain (P = .326), patient discomfort (P = .509), inability to chew (P = .936), or surgical chair time (P = .932) were recorded between the test and the control group. No statistically significant differences were recorded in terms of thickness of the palatal fibromucosa (P = .647) and thickness of the free gingival graft (P = .756) between groups. Postsurgical wound healing complications (ie, necrosis or infections) were not observed in both groups. Conclusion: Within their limitations, the present outcomes indicated that the application of L-PRF membrane at palatal donor sites after FGG harvesting did not produce significant advantages for the patients. [ABSTRACT FROM AUTHOR]

We studied the morphology of yarns obtained from Manila hemp (also known as Abacá) fiber bundles to find a possible correlation with the enhancement in mechanical properties of yarns relative to the original natural fiber bundle. Long Manila hemp fiber bundles had lignin and hemicelluloses removed, twisted and dried to form yarns. Scanning electron micrography revealed that the collapse of lumens inside the fibers leads to densification and consequent increase of tensile properties of the yarns. The densification occurs after the chemical removal of noncellulosic substances from the interstices of cellulose fibrils. These cellulosic elements are then bridged by hydrogen bonds during the drying step of yarn fabrication. [ABSTRACT FROM AUTHOR]

Natural fibers are biodegradable, lightweight, and low-cost in the creation of high performance engineered materials. The objective of this investigation is to comprehend the extraction procedure and characterization of natural cellulosic fibers extracted from Borassus flabellifer L. leaf. The obtained fibers were treated with sodium hydroxide solution to overcome the drawback of hydroxyl bonding. The essential properties of raw and treated fiber such as chemical composition, density, tensile strength, surface roughness, elements, functional group analysis, crystallinity index, crystallite size, maximum degradation temperature, and thermal stability were studied. The test result concluded that the alkali treatment improved the cellulose content while the hemicellulose, lignin, and wax content were reduced. This improved the tensile strength, density while the fiber weight decreased. The XRD analysis of raw and treated fiber confirmed the crystallinity index (50.34% from 46.58%) and crystallite size (2.72 nm from 2.36 nm) were improved after alkalization. The outcome of FTIR analysis confirmed the amorphous contents in borassus leaf fibers (BLF) were condensed due to the alkalization. The SEM analysis confirmed that the impurities and wax content of the outer surface of BLF were removed after alkali treatment. The result of TG analysis confirmed that the thermal stability temperature of alkali treated fiber had increased from 261 to 285 °C. The DTG analysis proved that the maximum fiber degradation temperature of alkali-treated BLF was increased from 316 to 365 °C. Thus, the surface modified fibers are appropriate materials for use as reinforcement in light weight high performance polymer composites. [ABSTRACT FROM AUTHOR]

Environmental pollution resulting in ecological imbalance and health hazards is among prominent global concerns. Among several causes of environmental pollution, dumping of nondegradable polymeric plastic into ecosystem is a major issue. Besides the environmental hazards associated with plastic, management of dumped plastic and recycling are a big challenge which have led to search for alternate sources for production of eco-friendly biodegradable plastics. Among different substrates, utilization of agricultural waste has been identified as most appropriate feedstock for bioplastic synthesis as along with synthesis of bioplastic, it simultaneously prevents dumping of agro waste into soil and water. High cellulose, pectin and starch content of agro waste justify it to be processed for bioplastic production. Besides agro waste, algae biomass is another economic and efficient feedstock for green plastic synthesis. Bioplastics can be effectively utilized in food packaging, agriculture, horticulture and manufacturing of numerous products; however, the commercial production and practical application of bioplastic are challenged by its durability, elasticity, tensile strength and biodegradability. The present review is a comparative study of different substrates and methods reported for synthesis of bioplastic along with their associated benefits and drawbacks. [ABSTRACT FROM AUTHOR]

Recently, considerable effort has been made to study cellulose/epoxy composites. However, there is a gap when it comes to understanding the post‐conditioning anomalous effect of moisture uptake on their mechanical and dynamic‐mechanical properties, and on their creep behavior. In this work, up to 10.0 wt% microcrystalline cellulose (MCC) was incorporated into epoxy resin by simple mixing and sonication. Epoxy/MCC composites were fabricated by casting in rubber silicone molds, and rectangular and dog‐bone test specimens were produced. The moisture uptake, dynamic mechanical, chemical, tensile, and creep behavior were evaluated. The incorporation of MCC increased the water diffusion coefficient. The changes in storage modulus and glass transition temperature, combined with Fourier‐transform infrared spectroscopy analysis, evidenced that water sorption in epoxies causes both plasticization and additional resin crosslinking, although the latter is prevented by the addition of MCC. The creep strain of the composites increased by 60% after conditioning, indicating that plasticization induced by water sorption plays an important role in the long‐term properties of the composites. [ABSTRACT FROM AUTHOR]

This study investigates the influence of hemicellulose (Hc) on the chemical composition, thermal stability, mechanical properties, and morphology of carboxymethyl cellulose (CMC). Hc was isolated from oil palm trunk and then added into CMC at 10–30 wt% to prepare Hc‐CMC films via solution casting method. The addition of Hc resulted in reduced visual transparency, rendering the blend films opaque. Fourier transform infrared spectroscopy verified the chemical interaction between Hc and CMC by revealing persistent and robust hydrogen bonding at specific spectral peaks (3483–3045 cm−1). The interaction between Hc and CMC was further indicated by the rougher interfacial structure as revealed in scanning electron microscopy (SEM). Thermal analysis via differential scanning calorimetry and thermogravimetry analysis indicated a decrement in thermal stability as Hc loadings increased in the CMC films. The highest tensile properties were observed in Hc‐CMC blend films at a 20 wt% Hc loading, showcasing notable enhancement about 23%. The 20 wt% Hc‐CMC blend films appeared as more suitable blending composition which having an enhanced physicochemical, thermal, and mechanical properties. This finding underscores its potential applicability in diverse industrial sectors, particularly in packaging applications. [ABSTRACT FROM AUTHOR]

The dissipation of charges by aging or under the effect of humid conditions considerably impedes a broader utilization of electrostatic fields in aerosol filtration. This study introduces a respiration‐driven air filter (RAF) that continuously generates triboelectric charges within a pair of tribolayers, which facilitates a sustained filtration performance. Such system is integrated in a multilayer unit that is inserted in personal protective equipment (RAFM) to efficiently capture, sense, and degrade airborne pollutants with no need for external power sources. The triboelectric nanogenerator‐based RAF continuously replenishes static charges and maintains an electrostatic field through breathing by the effect of contact‐electrification between two cellulose‐based tribolayers: a cellulose/metal organic framework cryogel (electron donor) and a cellulose–based electrospun membrane (electron acceptor). Notably, the triboelectric field of the RAF's tribolayer pair substantially enhances both the filtration efficiency (up to 93.8% for 0.3 µm particulate matter) and sensing/catalytic degradation (ammonia; degradation >20%). When integrated in a circuit module, the RAFM effectively monitors respiration dynamics, acting as a breathing indicator/regulator. Overall, this study adds to the promise of tribogeneration through cellulose‐based materials and its application in exposure‐risk operations. [ABSTRACT FROM AUTHOR]

Transparent polymer materials, such as plastics, have become widely used in the packaging industry due to their excellent properties. However, their nondegradability has led to a significant environmental issue known as "white pollution." To address this issue, a transparent antibacterial film material was prepared using carboxymethyl cellulose and carboxymethyl chitosan as raw materials through an acid‐assisted freeze–thaw strategy. The material exhibits optical transmittance exceeding 90% and a tensile strength of up to 124.1 MPa. Meanwhile, this material demonstrated excellent waterproof performance as well as antibacterial activity to Staphylococcus aureus and Escherichia coli. Therefore, this film material holds promising potential for development in antibacterial food packaging. [ABSTRACT FROM AUTHOR]

Most reduced organic matter entering activated sludge systems is particulate (1–100-µm diameter) or colloidal (0.001–1-µm diameter), yet little is known about colonization of particulate organic matter by activated sludge bacteria. In this study, colonization of biopolymers (chitin, keratin, lignocellulose, lignin, and cellulose) by activated sludge bacteria was compared with colonization of glass beads in the presence and absence of regular nutrient amendment (acetate and ammonia). Scanning electron microscopy and quantitative PCR revealed chitin and cellulose were most readily colonized followed by lignin and lignocellulose, while keratin and glass beads were relatively resistant to colonization. Bacterial community profiles on particles compared to sludge confirmed that specific bacterial phylotypes preferentially colonize different biopolymers. Nitrifying bacteria proved adept at colonizing particles, achieving higher relative abundance on particles compared to bulk sludge. Denitrifying bacteria showed similar or lower relative abundance on particles compared to sludge. Key points: • Some activated sludge bacteria colonize natural biopolymers more readily than others. • Nitrifying bacteria are overrepresented in natural biopolymer biofilm communities. • Biopolymers in wastewater likely influence activated sludge community composition. [ABSTRACT FROM AUTHOR]

In this work, phosphate-rich cellulose beads (CBPs) were first used for cesium extraction from aqueous solutions. These green, abundant, cheap, and renewable CBPs demonstrated a high adsorption capacity and fast absorption rate. Besides, the CBPs also exhibited excellent stability and recycling performance, as well as good selectivity. This study presents the promising application potential of cellulose for efficient cesium extraction from aqueous media. [ABSTRACT FROM AUTHOR]

Light‐responsive cellulose nanocrystal@polydopamine (CNC@PDA) modified fluorinated polyacrylate was synthesized by Pickering emulsion polymerization with light‐responsive block copolymer modified CNC@PDA as stabilizer. The epoxy groups in poly(acrylic acid‐co‐acrylamide)‐b‐poly(glycidyl methacrylate)‐b‐poly(hexafluorobutyl acrylate‐co‐coumarin) amphiphilic triblock copolymer reacted with the hydroxyl and amino groups on the surface of CNC@PDA to form the modified CNC@PDA. The successful preparation of modified CNC@PDA was confirmed by means of FT‐IR, XRD, TG, UV–Vis, surface tension measurement, and X‐ray photoelectron spectroscopy (XPS) techniques. The results showed that the modified CNC@PDA had light‐responsive and amphiphilic properties, and could be used as stabilizer to form stable Pickering emulsion. And the influence of modified CNC@PDA dosage on emulsion polymerization and film performance was systematically studied. The latex particle size decreased initially with increasing modified CNC@PDA dosage, from 0.6 to 1.0 wt%, and then increased. The mechanical, self‐healing, and water–oil repellent properties of film were enhanced initially with increasing modified CNC@PDA dosage, from 0.6 to 1.0 wt%, and then declined. Atomic force microscope confirmed that the latex film had a rough surface. Moreover, the latex film comprising 1.0 wt% modified CNC@PDA presented not only high tensile strength (4.92 MPa), large elongation at break (657.70%), and superior oil/water repellency but also excellent self‐healing property. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous zinc metal batteries (RAZMBs) have received extensive attention for large-scale energy storage systems due to the merits of Zn anodes, including moderate volumetric and gravimetric energy density, low redox potential, abundant reserve, low cost and impressive intrinsic safety. However, Zn anodes suffer from a series of adverse reactions (dendrite growth, hydrogen evolution, and surface passivation) resulting in low Coulombic efficiency, large polarization, and unsatisfied cycling performance, which inevitably hinder the wide application of RAZMBs. To address the above issues, cellulose-based materials are widely used for Zn anode protection because of their unique physical and chemical properties and other advantages such as biocompatibility, non-toxicity, degradability and easy extraction. In order to better understand the current progress in cellulose-based materials for the Zn anode protection, we have classified and summarized the relevant literatures. In this review, we summarize and elaborate the causes of poor reversibility for Zn anodes, including dendrite formation, hydrogen evolution, and surface passivation. Subsequently, the effective strategies (anode interfacial engineering, gel electrolyte optimization, and separator modification) of cellulose-based materials toward stabilizing Zn anodes are overviewed. In the end, the existing challenges and prospects of cellulose-based materials in Zn anode protection are summarized to shed light on future work. [ABSTRACT FROM AUTHOR]

Dye wastewater discharges threaten fragile aquatic ecosystems. Photocatalysis has been applied as an effective, viable, and economical option to achieve dye degradation. However, current photocatalysts suffer from large bandgaps, powder agglomeration, difficult recovery, and cannot be recycled. Herein, a novel Bi2S3/ZnS heterojunction loaded cellulose/chitosan (BiZnCCS) with highly efficient photocatalytic activities for CR pollutant degradation was designed and fabricated via a simple hydrothermal method. BiZnCCS has a large pore size of 2 μm with a high porosity of 71.62%, which increases the contact area with CR and facilitates the adsorption of CR. The pore wall was uniformly loaded with Bi2S3/ZnS particles, and the degradation rate of CR could reach 97.8% under simulated visible light irradiation. By adjusting the composition ratio, BiZnCCS was able to withstand a stress of about 82.45 kPa, and the CR removal rate was still maintained at about 85% after 7 cycles of testing. By creating a synergistic adsorption-photocatalytic degradation mechanism, BiZnCCS has the ability to efficiently remove CR under visible light, which provides a new material for the treatment of dye wastewater. [ABSTRACT FROM AUTHOR]

The biodegradable biomass adsorbent (cellulose-g-PSS) was synthesized in LiCl/N, N-dimethyl acetamide by the free-radical grafting polymerization reaction between sodium styrene sulfonate (SSS) and cellulose. Systematic optimization was conducted on many reaction parameters, including reaction time, monomer dosage, and reaction temperature. The grafting yield of cellulose-g-PSS was 50.16%. The chemical structures, physical, and chemical characteristics of cellulose-g-PSS were characterized by FTIR, SEM, PZC, 1H NMR, XRD, TGA and XPS. An assessment was conducted to determine the sorption of Ce (III) on cellulose-g-PSS by changing the contact time, adsorbent dosage, pH, initial Ce (III) concentration, and NaCl concentration. The process of adsorption rapidly reached a state of equilibrium within a time frame of 25 min and was well explained using pseudo-second-order kinetic and Langmuir isotherm model. The maximum adsorption capacity for Ce (III) obtained from the Langmuir isotherm model was 84.80 mg·g−1. The impact of NaCl concentration on the sorption of Ce (III) and XPS analysis showed that Ce (III) ions were adsorbed onto cellulose-g-PSS through ion-exchange mechanism. As a whole, cellulose-g-PSS exhibited great potential in rare earth wastewater treatment. [ABSTRACT FROM AUTHOR]

In this work, we used cellulose nanofibers (CNF) as the skeleton, Fe3O4@ZnO composite particles as magnetic synergist particles, 3‐(2‐aminoethylamino) propyltrimethoxysilane (AS) and trimethoxy(octyl)silane (OTMS) as water‐based hydrophobic modifiers to prepare magnetic and superhydrophobic cellulose nanofibers based‐aerogel with low density and intricate three‐dimensional structure. Fe3O4@ZnO confers magnetic properties (3.82 emu/g) and exceptional thermal stability (water contact angle of 150.1° at 200 °C) to the system, while the combination with OTMS/AS endows the system superhydrophobic (157.5°) and excellent mechanical properties (stress of 96.95 kPa at 80% strain). It is worth noting that in the process of modifying the system with OTMS/AS, no organic solvents and acidic substances are used in the solution. Benefiting from their synergies, the system demonstrates a notable oil absorption capacity (12.31–41.91 g/g) and outstanding oil selectivity (exceeding 90%), driven by gravity alone. Interestingly, this system, marked by its cost‐effectiveness, simplicity, eco‐friendliness, and heightened efficiency, holds promising prospects for diverse applications in different oil–water separation behavior and purifying industrial oil wastewater, as well as oil flooding incidents. [ABSTRACT FROM AUTHOR]

Glassy polymers stiffen or soften when exposed to volatile compounds, depending on the specific combination of polymer compound and the specimen history. Relevant to the long‐term applicability of the separation membranes, three common membrane glassy polymers are studied in this work. Freshly prepared and 2‐years aged films from cellulose triacetate (CTA), poly[1‐(trimethylsilyl)‐1‐propyne] (PTMSP), and the archetypal polymer of intrinsic microporosity (PIM‐1) were tested using isothermal Dynamic Mechanical Analysis (DMA) at varied vapor activity. Vapors of organic compounds, in which the polymers do and do not dissolve in the liquid phase (solvents and nonsolvents), were studied at 40 °C, namely: dichloromethane (DCM, solvent), p‐xylene (solvent for PTMSP and PIM‐1), and methanol (nonsolvent). Functional groups of the mer units sensitive to the dissolution were identified using Raman spectroscopy. All aged films were stiffer than the freshly prepared ones. Stiffening prevailed for most freshly prepared film‐vapor pairs at low vapor saturations (activity < ≈0.4), except CTA and PIM‐1 in nonsolvent methanol vapors. Softening prevailed for the aged films and higher vapor saturations (activity > ≈0.6). Vapors of the solvents and nonsolvents did not show the expectable prevalence of softening and stiffening, respectively. Physical aging influenced the stiffening and softening of polymer glasses expectably. [ABSTRACT FROM AUTHOR]

To develop a green nanomaterial for specialty applications, spherical nanocellulose (SNC) was functionalized to a semicarbazone‐Schiff base via a polymer analogous reaction. Firstly, SNC was synthesized from cellulose extracted from huge forest biomass, pine needles (PNs). The glucopyranose ring of SNC was oxidatively cleaved at C2–C3 to form SNC‐dialdehyde (SNC‐DA) by periodate oxidation. Both the aldehydic groups generated were reacted with semicarbazide to form a semicarbazone‐Schiff base, referred to as functional spherical nanocellulose (FSNC). All the materials synthesized were characterized by FTIR, FESEM, EDS, TEM, and XRD studies. The FSNC was evaluated as an adsorbent for Hg2+ ions. The adsorption adhered to pseudo‐second order kinetics and Langmuir adsorption isotherm having a maximum adsorption capacity/Lungmuir adsorption capacity of 172.412 mg/g at 60 min. The selectivity of FSNC for Hg2+ ions was confirmed from its appreciable removal (82%) from solution in tap water and 70% with other metal ions. FSNC exhibited bifunctional nature as it possesses antimicrobial activity against bacteria, that is, Gram (+) (Bacillus aereus) and Gram (−) (Escherichia coli and Salmonella typhi), and a fungus Byssochlamys fulva. FSNC showed good recyclability up to eight sorption–desorption cycles. Thus, we have valorized biomass into an eco‐friendly and low‐cost bifunctional material as an adsorbent for Hg2+ ions cum antimicrobial agent. Highlights: Spherical nanocellulose (SNC) prepared via acidic hydrolysis from pine needlesSNC functionalized to semicarbazone‐based bifunctional Schiff baseThe Schiff base is a rapid and efficient Hg2+ ions adsorbentThe Schiff base has good antimicrobial activities against Gram (−) bacteriaBiowaste‐based adsorbent has the potential to sustain the bio‐circular economy [ABSTRACT FROM AUTHOR]

Due to increased environmental awareness, the depletion of fossil fuels, and expanding ecological concerns, today's society has a larger need for environmentally friendly materials. The idea of sustainable development of environmental material resources with enhanced economic activities was born from the rise in ecological consciousness. The textile industry generates enormous amounts of cotton waste. The environmental impact of disposing of this cotton waste makes it difficult for the textile sector to dispose of the vast amounts of produced cotton waste. As a result, all-cellulose composites (ACCs) have piqued the interest of researchers in recent years. All-cellulose composites are cellulose-based mono-component cellulose composites in which the reinforcing phase is typically composed of high-strength cellulose fibres, and the matrix is composed of regenerated cellulose. This composite type is distinguished by its exceptional interfacial compatibility and biodegradability due to the matrix and reinforcing phase having common cellulosic compositions. ACCs will become a more alluring option as enterprises prioritize sustainability and environmental responsibility because they can be recycled and reused rapidly and simply. This will contribute to less waste and enhance the overall sustainability of our society. This review paper discusses various methods to develop ACCs, textile waste-based thermoset and thermoplastic composites and textile waste-based cellulose composites (TWCCs). This review paper emphasizes approaches to develop TWCCs and the challenges and opportunities in TWCCs. [ABSTRACT FROM AUTHOR]

Spinning of cellulose dissolved in 3-alkyl-1-methylimidazolium ionic liquids is a current approach to manmade cellulosic fibers. To curb cellulose degradation in the dope, stabilizers have to be used. Generation of chromophores in the dope and the resulting fibers is unavoidable, with most of the discoloration resulting from the employed antioxidants. In the present work, the chemical structures of the chromophores derived from the most common "green" stabilizers currently used, namely propyl gallate (a gallic acid derivative), hydroxytyrosol (and antioxidant from olives), and tocopheramines (vitamin E derivatives), were elucidated by a combination of analytical techniques and final confirmation by comparison with independently synthesized samples. While most compounds are oxidation and rearrangement products of the antioxidants themselves, coupling products with the ionic liquid´s imidazolium cations were also found. Identification of the colored compounds is a critical issue for both the optimization of fiber bleaching steps and solvent purification/recovery in the spinning process. Now that the nature of the generated chromophores is known, milder yet more effective bleaching treatments can be developed and solvent purification/recycling can be specifically optimized. [ABSTRACT FROM AUTHOR]

Hypochlorous acid bleaching under amine catalysis (Hcat bleaching stage) is an optimized bleaching stage variant that is characterized by working at weakly acidic, near-neutral pH, having high bleaching efficiency, and discharging only very small amounts of chloro-organics. This study addressed the chemical fate of the used 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyst. While literature proposed either homolytic or heterolytic breakage of one ethylene bridge and subsequent release of the resulting fragments as two molecules of formaldehyde, we demonstrated the degradation to proceed by ionic elimination of one ethylene bridge starting from mono-N-chlorinated DABCO. The resulting N-vinyl (enamine) derivative adds water under the release of acetaldehyde and formation of piperazine. The generation of acetaldehyde was experimentally confirmed by 2,4-dinitrophenylhydrazine trapping, directly from the processing liquid. The experimental findings agreed superbly with computations which showed the "acetaldehyde mechanism" to be much favored over the previously proposed pathways under C–C bond cleavage and release of formaldehyde. The results of this study add to a better understanding of the novel Hcat bleaching system. [ABSTRACT FROM AUTHOR]

In the present study, cellulose was effectively separated from eucalyptus wood with ternary solvents containing organic base 1,1,3,3-tetramethyl guanidine and other organic solvents such as morpholine, N-ethyl morpholine, dimethyl formamide, glycerin, ethylene glycol and diethylene glycol. It was found that the combination of 1,1,3,3-tetramethyl guanidine with morpholine was favorable for achieving high delignification and less loss of cellulose. The removal of lignin and hemicellulose achieved 89.8% and 81.4% after heating for 6 h at 160 °C, respectively. It was found that the combination of 1,1,3,3-tetramethyl guanidine with morpholine was favorable for achieving high delignification and less loss of cellulose. The removal of lignin and hemicellulose achieved 89.8% and 81.4% after heating for 6 h at 160 °C, respectively. The addition of morpholine and water promoted the dissolution of lignin and reduced the degradation of cellulose. Subsequently, the crude cellulose was further purified through a simplified bleaching process, the final removal of lignin and hemicellulose increased to 98.7% and 97.5% respectively, and cellulose with a purity of 96.9% was achieved. The scanning electron microscopy analysis indicated that the diameter of cellulose bundles decreased from about 250 μm to about 20 μm after organic solvents treatment. The fiber bundle was completely separated into a single fiber with a diameter of about 5–10 μm after bleaching process. X-ray diffraction analysis revealed an increase in the crystallinity of fiber from 69.4% to 83.3%, implying a reduction of lignin and hemicellulose in eucalyptus. Fourier transform infrared spectra revealed the high selective removal of lignin and hemicellulose. Two-dimensional 1H-13C Heteronuclear singular quantum correlation was performed to investigated the structure units and linkages of lignin and found that only the structural signal of C5-H5 in guaiacyl (G5) alone existed in the aromatic region, while the signals -OCH3, Cγ–Hγ in β-O-4' (Aγ) and β-β' (Cγ) remained in the side chain region, indicating that lignin could be effectively degraded and dissolved by the ternary solvents. In conclusion, high purity cellulose was obtained from eucalyptus wood by environmentally friendly and recyclable processes. [ABSTRACT FROM AUTHOR]

In this study, novel durable flame-retardant lyocell fibres were designed by the addition of phosphorylated cellulose and physical blending of montmorillonite (MTT) within the fibres. The influences of phosphorylation and MTT blending on the flame retardancy of lyocell fibres were investigated. Additionally, the synergistic effects of the two flame retardant methods were also discussed. Furthermore, phosphorylated cellulose and MTT-filled lyocell fibres were prepared, and their flame retardancy was measured. Phosphorylation (limiting oxygen index (LOI) > 28%) was found to improve the flame retardancy of the lyocell fibres; nevertheless, excessive phosphorylation decreased the crystallinity of the cellulose and decreased the mechanical strength of the fibres. Montmorillonite was added to the lyocell fibres to achieve durable flame retardancy, whereas the LOI was less than 24%. Interestingly, lyocell fibres with LOIs greater than 28% and strengths greater than 2.0 cN/dtex could be obtained from the phosphorylated cellulose with MTT filling. The thermogravimetric (TG) and TG-infrared (TG-IR) experimental results showed that MTT played a role in the condensed-phase flame retardancy, while phosphorylated cellulose played a role in the gas-phase and condensed-phase flame retardancy. The Raman test results showed that the combination of MTT and phosphorylated cellulose enhanced the graphitization degree of the residue char. In our study, a novel flame-retardant method for the preparation of lyocell fibres with permanent flame retardancy and high tensile strength was developed; moreover, our results contribute to the development of industrial-grade fabrication of new flame-retardant fibre materials. [ABSTRACT FROM AUTHOR]

Heavy metal ions and dyes in wastewater pose a severe hazard to ecological system and human health. This study used sulfamic acid (SA) to modify cellulose for adsorbent material preparation. The results from the structural characterization indicated that cellulose was successfully modified by introducing sulfonic acid groups to obtain sulfamic acid modified cellulose (SAMC). Subsequently, SAMC was prepared into spheres via being dissolved in ionic liquid and obtaining in antisolvent. The adsorption performance of SAMC aerogel spheres was investigated using methylene blue (MB) and lead ions (Pb2+). The maximum absorption capacity of SAMC aerogel spheres to MB and Pb2+ achieved 14.53 mg/g and 112.15 mg/g, respectively. The adsorption process conformed to the pseudo-second-order (PSO) model and Langmuir model. The adsorption mainly involved chemical action via coordination interaction between -SO32− and MB/Pb2+. Thermodynamic experiments confirmed that the adsorption process in the experiment was a spontaneous endothermic process. Therefore, this study provided a simple adsorbent production method for wastewater treatment. [ABSTRACT FROM AUTHOR]

Cellulose paper has been studied for its application as an antibacterial filter, due to its robust porous structure, minimal ecological footprint, biocompatibility, and inherent antibacterial properties. Moreover, its properties can be further enhanced via surface functionalization with metallic nanoparticles (NPs) such as silver, zinc, etc. However, the synthesis of metallic NPs is challenging, costly, and environmentally harmful. On the other hand, carbon nanotubes (CNTs) are highly suitable as an additive to cellulose paper due to their high electrical conductivity, excellent mechanical strength, ease of fabrication, and antibacterial properties. In this study, we coated multi-walled carbon nanotubes (MWCNTs) on Hanji, a traditional Korean paper, using a simple dipping method and investigated its antibacterial activity against Escherichia coli (E. coli). The MWCNT-coated Hanji exhibited an inhibition efficiency of ~ 93% against E. coli cells. Moreover, the MWCNT coating resulted in improved mechanical strength, enhanced electrical conductivity, and increased hydrophobicity of the Hanji. Furthermore, it was observed that MWCNTs exhibited exceptionally stable adhesion to the Hanji surface. Our finding shows that MWCNT-coated Hanji could be utilized as an antibacterial material that is used as masks, air pollution filters, and wallpapers in hospitals and residential complexes, and an efficient platform for antiviral studies. [ABSTRACT FROM AUTHOR]

Crystalline nanocellulose is widely used for example, in the paper-making and food industries, as support matrix material or reinforcement of polymer materials, but also in drug carrier and nanomedicine applications. Interestingly, aqueous solutions of cellulose are extremely sensitive to small amounts of added salt yet mere considerations of charge screening leave open questions regarding the mechanisms, especially for unmodified cellulose in aqueous solutions. Here, we map NaCl ion distributions and the effect of added NaCl salt on the hydration of I β cellulose nanocrystal (CNC) surfaces by atomistic detail molecular dynamics simulations with explicit water solvent. The simulations reveal the dependency of the hydration layers of the six surfaces of CNCs on the ions, as well as NaCl ion binding sites, and preferences in terms of binding free energy for the ions near CNC surfaces at different NaCl concentrations. We discuss the modelling results against our prior rheology characterization of cellulose solutions. Together, the results indicate that the high sensitivity of cellulose aqueous solutions to added salt rises from the ions near the surface changing locally the ordering and structure of the hydration layers of the CNC surfaces. The revealed mechanism of salt-induced viscosity changes in cellulose aqueous solutions allows advanced design of gelling CNC systems for various end uses and may also guide tuning cellulose interactions by different solvent environments. [ABSTRACT FROM AUTHOR]

A comprehensive study of the cellulose particle shape effect on electrorheological activity of their suspensions in polydimethylsiloxane was performed. Microparticles, nanorods and porous composite particles of cellulose with polyethylene glycol were considered as a filler. The structure of particles was established by a set of complementary methods, such as electron microscopy, infrared spectroscopy, and wide-angle X-ray scattering. The rheological behavior of suspensions filled by various types of particles changes under an electric field. The yield stress increases with electric field strength. The role of particle shape on the electrorheological properties of suspensions was revealed. The values of the yield stress of suspensions increase from microparticles to nanorods and porous composite particles at the same concentration and electric field strength. Porous composite particles of cellulose, a novel filler obtained by freeze-drying, demonstrates an enhanced electrorheological response compared to micro- and nanoparticles. The yield stress reaches 450 Pa at 7 kV/mm at an extremely low concentration of 1.0 wt%. Moreover, the porosity of the particles significantly increases the sedimentation stability of cellulose suspensions in polydimethylsiloxane. The high porosity of the filler makes it possible to obtain highly efficient electrorheological fluids at a sufficiently low concentration of the dispersed phase. [ABSTRACT FROM AUTHOR]