Aging Resistance Evaluation of Aged Paper Reinforced with Different Nanocelluloses

Paper documents experience severe acidification and embrittlement.Nanocellulose is an excellent reinforcement material for paper documents owing to its compatibility and excellent mechanical strength.However,little research has been conducted on the aging resistance of nanocellulose-reinforced paper.In this study,six types of nanocelluloses were used to reinforce aged paper.The reinforcement and anti-aging performances were evaluated,and the anti-aging mechanism was further clarified.Nanocellulose with a high degree of polymerization can better enhance aged paper,and non-chemical nanocellulose also shows better anti-aging performance,such as nanocellulose prepared by mechanical or biological methods.However,nanocellulose prepared using chemical methods exhibits poor reinforcement and anti-aging performance.This is because it has a small particle size that is not beneficial for physical crosslinking with paper fibers.More importantly,the introduction of acidic or oxidizing groups on nanocellulose accelerates the acid hydrolysis and oxidation rate of paper fibers,especially nanocellulose prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl oxidation,which should not be used to protect paper documents.

Hollow Metal-Organic Framework/MXene/Nanocellulose Composite Films for Giga/Terahertz Electromagnetic Shielding and Photothermal Conversion

With the continuous advancement of communication technology,the escalating demand for electromagnetic shielding interference(EMI)materials with multifunctional and wideband EMI performance has become urgent.Controlling the electrical and magnetic components and designing the EMI material structure have attracted extensive interest,but remain a huge challenge.Herein,we reported the alternating electromagnetic structure composite films composed of hollow metal-organic frameworks/layered MXene/nanocellulose(HMN)by alternating vacuum-assisted filtration process.The HMN composite films exhibit excellent EMI shielding effectiveness performance in the GHz frequency(66.8 dB at Kaband)and THz frequency(114.6 dB at 0.1-4.0 THz).Besides,the HMN composite films also exhibit a high reflection loss of 39.7 dB at 0.7 THz with an effective absorption bandwidth up to 2.1 THz.Moreover,HMN composite films show remarkable photothermal conversion performance,which can reach 104.6℃under 2.0 Sun and 235.4℃under 0.8 W cm^(−2),respectively.The unique micro-and macrostructural design structures will absorb more incident electromagnetic waves via interfacial polarization/multiple scattering and produce more heat energy via the local surface plasmon resonance effect.These features make the HMN composite film a promising candidate for advanced EMI devices for future 6G communication and the protection of electronic equipment in cold environments.

Potential of Bamboo Species Guadua trinii and Guadua angustifolia for Nanocellulose Production

Non-traditional lignocellulosic materials are a significant resource for producing high-value products,including nanocellulose.This work studied the nanocellulose obtention from chemical pulps of the two fast-growing bamboo species,Guadua trinii,and Guadua angustifolia.Chemical pulps were produced by soda-anthraquinone(S)pulping from both autohydrolysis-pretreated(H)and unpretreated bamboo chips.Autohydrolysis-pretreated(SHP)and unpretreated soda-anthraquinone(AQ)(SP)pulps were characterized by yield,Kappa number,alpha,beta,and gamma cellulose,degree of polymerization,water retention value,and crystallinity.The nanocellulose was produced by a sequential chemical oxidation treatment(2,2,6,6-tetramethylpiperidine-1-oxyl,TEMPO reagent)and mechanical nanofibrillation.Nanocellulose was characterized by carboxylic group content and viscosity.The results revealed that autohydrolysis pretreatment resulted in a higher hemicelluloses extraction in G.angustifolia.In contrast,the pulping yield of unpretreated samples was higher for G.trinii,and the soda-AQ pulps from this species exhibited better delignification than the autohydrolysis-pretreated pulps.The crystallinity index values of the obtained pulps were high(>80%),and the alpha-cellulose contents were similar.The viscosities of the aqueous nanocellulose suspensions were higher for the nanocellulose solutions obtained from the unpretreated soda-AQ pulps.Besides,nanocellulose from G.trinii unpretreated soda-AQ pulps had a higher rate of carboxylic groups.The results of this work are significant in assessing the potential of both bamboo species as a source of high-value products within the biorefinery framework because the viscosities of the aqueous nanocellulose suspensions depend on the size and shape of nanofibrils.It has significant importance for industrial unit operations and potential applications.

Artificial Neural Network Modeling for Predicting Thermal Conductivity of EG/Water-Based CNC Nanofluid for Engine Cooling Using Different Activation Functions

A vehicle engine cooling system is of utmost importance to ensure that the engine operates in a safe temperature range.In most radiators that are used to cool an engine,water serves as a cooling fluid.The performance of a radiator in terms of heat transmission is significantly influenced by the incorporation of nanoparticles into the cooling water.Concentration and uniformity of nanoparticle distribution are the two major factors for the practical use of nanofluids.The shape and size of nanoparticles also have a great impact on the performance of heat transfer.Many researchers are investigating the impact of nanoparticles on heat transfer.This study aims to develop an artificial neural network(ANN)model for predicting the thermal conductivity of an ethylene glycol(EG)/waterbased crystalline nanocellulose(CNC)nanofluid for cooling internal combustion engine.The implementation of an artificial neural network considering different activation functions in the hidden layer is made to find the bestmodel for the cooling of an engine using the nanofluid.Accuracies of the model with different activation functions in artificial neural networks are analyzed for different nanofluid concentrations and temperatures.In artificial neural networks,Levenberg–Marquardt is an optimization approach used with activation functions,including Tansig and Logsig functions in the training phase.The findings of each training,testing,and validation phase are presented to demonstrate the network that provides the highest level of accuracy.The best result was obtained with Tansig,which has a correlation of 0.99903 and an error of 3.7959×10^(–8).It has also been noticed that the Logsig function can also be a good model due to its correlation of 0.99890 and an error of 4.9218×10^(–8).Thus ourANNwith Tansig and Logsig functions demonstrates a high correlation between the actual output and the predicted output.

Fabrication of Free Standing Nanocellulose Film via Spray Coating and its Biomedical Application: A Review

Spraying nanocellulose onto films provides a quick and scalable way to create free-standing films with exceptional consistency and customizable thickness. This method increases the application of nanocellulose films in various industries and satisfies the requirements of large-scale production. In the field of biomedicine, spray-coated free-standing nanocellulose films hold great promise for applications such as drug delivery, tissue engineering, wound healing, device coatings, and biosensing. They are excellent nanomaterials for a variety of biomedical applications due to their special qualities, including biocompatibility, high mechanical strength, porous structure, large surface area, and adaptability. This paper reviewed the detailed exposure of the spray coating process of nanocellulose suspension onto free- standing films and its biomedical applications.

Smart drug delivery system based on nanocelluloses

Nanocelluloses,also referred as nano-structured cellulose,including cellulose nanocrystals(CNC),cellulose nanofibrils(CNF)and bacterial cellulose(BC),are a family of abundant biomass and renewable materials in nature.Because of their excellent physical,mechanical,and biological properties,in particular biocompatibility,biodegradability,and low cytotoxicity,nanocelluloses have become indispensable for the design of new biomaterials.

Nanocellulose-Assisted Construction of Multifunctional MXene-Based Aerogels with Engineering Biomimetic Texture for Pressure Sensor and Compressible Electrode

Multifunctional architecture with intriguing structural design is highly desired for realizing the promising performances in wearable sensors and flexible energy storage devices.Cellulose nanofiber(CNF)is employed for assisting in building conductive,hyperelastic,and ultralight Ti_(3)C_(2)T_(x)MXene hybrid aerogels with oriented tracheid-like texture.The biomimetic hybrid aerogels are constructed by a facile bidirectional freezing strategy with CNF,carbon nanotube(CNT),and MXene based on synergistic electrostatic interaction and hydrogen bonding.Entangled CNF and CNT“mortars”bonded with MXene“bricks”of the tracheid structure produce good interfacial binding,and superior mechanical strength(up to 80%compressibility and extraordinary fatigue resistance of 1000 cycles at 50%strain).Benefiting from the biomimetic texture,CNF/CNT/MXene aerogel shows ultralow density of 7.48 mg cm^(-3)and excellent electrical conductivity(~2400 S m^(-1)).Used as pressure sensors,such aerogels exhibit appealing sensitivity performance with the linear sensitivity up to 817.3 kPa^(-1),which affords their application in monitoring body surface information and detecting human motion.Furthermore,the aerogels can also act as electrode materials of compressive solid-state supercapacitors that reveal satisfactory electrochemical performance(849.2 mF cm^(-2)at 0.8 mA cm^(-2))and superior long cycle compression performance(88%after 10,000 cycles at a compressive strain of 30%).

Bismuth-Complex-Incorporated Nanocellulose Sheet for Biomedical Application:A Review on New Nanocellulose Composites

Antibiotic resistance is one of the major issues in the medical field and a potential threat to human health.However,newly emerging antimicrobial compounds failed to combat antimicrobial resistance developed by bacterial pathogens.Recently,a bismuth-based complex has been developed to eradicate antimicrobial-resistant microorganism infections.The complex is known as organobismuth(III)phosphinate,which is said to be a potential broad-spectrum antimicrobial agent.This complex has been incorporated into the nanocellulose suspension to fabricate a biomedical composite for various applications.The composite can be fabricated by two methods namely vacuum filtration and spray coating.In this paper,the surface and topography of the composite are investigated and discussed in terms of SEM micrographs and their antimicrobial potential.This review focuses on the organo-bismuth nanocellulose composite and its biomedical application in the future.

A Review on Surface?Functionalized Cellulosic Nanostructures as Biocompatible Antibacterial Materials

As the most abundant biopolymer on the earth,cellulose has recently gained significant attention in the development of antibacterial biomaterials.Biodegradability,renewability,strong mechanical properties,tunable aspect ratio,and low density offer tremendous possibilities for the use of cellulose in various fields.Owing to the high number of reactive groups(i.e.,hydroxyl groups)on the cellulose surface,it can be readily functionalized with various functional groups,such as aldehydes,carboxylic acids,and amines,leading to diverse properties.In addition,the ease of surface modification of cellulose expands the range of compounds which can be grafted onto its structure,such as proteins,polymers,metal nanoparticles,and antibiotics.There are many studies in which cellulose nano-/microfibrils and nanocrystals are used as a support for antibacterial agents.However,little is known about the relationship between cellulose chemical surface modification and its antibacterial activity or biocompatibility.In this study,we have summarized various techniques for surface modifications of cellulose nanostructures and its derivatives along with their antibacterial and biocompatibility behavior to develop non-leaching and durable antibacterial materials.Despite the high effectiveness of surface-modified cellulosic antibacterial materials,more studies on their mechanism of action,the relationship between their properties and their effectivity,and more in vivo studies are required.

Elastic Aerogels of Cellulose Nanofibers@Metal–Organic Frameworks for Thermal Insulation and Fire Retardancy

Metal–organic frameworks(MOFs)with high microporosity and relatively high thermal stability are potential thermal insulation and flame-retardant materials.However,the difficulties in processing and shaping MOFs have largely hampered their applications in these areas.This study outlines the fabrication of hybrid CNF@MOF aerogels by a stepwise assembly approach involving the coating and cross-linking of cellulose nanofibers(CNFs)with continuous nanolayers of MOFs.The cross-linking gives the aerogels high mechanical strength but superelasticity(80%maximum recoverable strain,high specific compression modulus of^200 MPa cm3 g−1,and specific stress of^100 MPa cm3 g−1).The resultant lightweight aerogels have a cellular network structure and hierarchical porosity,which render the aerogels with relatively low thermal conductivity of^40 mW m−1 K−1.The hydrophobic,thermally stable MOF nanolayers wrapped around the CNFs result in good moisture resistance and fire retardancy.This study demonstrates that MOFs can be used as efficient thermal insulation and flame-retardant materials.It presents a pathway for the design of thermally insulating,superelastic fire-retardant nanocomposites based on MOFs and nanocellulose.

Nanocellulose-Graphene Hybrids: Advanced Functional Materials as Multifunctional Sensing Platform

Naturally derived nanocellulose with unique physiochemical properties and giant potentials as renewable smart nanomaterials opens up endless novel advanced functional materials for multi-sensing applications.However,integrating inorganic functional two-dimensional carbon materials such as graphene has realized hybrid organic-inorganic nanocomposite materials with precisely tailored properties and multi-sensing abilities.Altogether,the affinity,stability,dispersibility,modification,and functionalization are some of the key merits permitting their synergistic interfacial interactions,which exhibited highly advanced multifunctional hybrid nanocomposites with desirable properties.Moreover,the high performance of such hybrids could be achievable through green and straightforward approaches.In this context,the review covered the most advanced nanocellulose-graphene hybrids,focusing on their synthetization,functionalization,fabrication,and multi-sensing applications.These hybrid films exhibited great potentials as a multifunctional sensing platform for numerous mechanical,environmental,and human bio-signals detections,mimicking,and in-situ monitoring.

Wet spinning of fiber-shaped flexible Zn-ion batteries toward wearable energy storage

High-performance flexible one-dimensional(1D)electrochemical energy storage devices are crucial for the applications of wearable electronics.Although much progress on various 1D energy storage devices has been made,challenges involving fabrication cost,scalability,and efficiency remain.Herein,a highperformance flexible all-fiber zinc-ion battery(ZIB)is fabricated using a low-cost,scalable,and efficient continuous wet-spinning method.Viscous composite inks containing cellulose nanofibers/carbon nanotubes(CNFs/CNTs)binary composite network and either manganese dioxide nanowires(MnO_(2) NWs)or commercial Zn powders are utilized to spinning fiber cathodes and anodes,respectively.MnO_(2) NWs and Zn powders are uniformly dispersed in the interpenetrated CNFs/CNTs fibrous network,leading to homogenous composite inks with an ideal shear-thinning property.The obtained fiber electrodes demonstrate favorable uniformity and flexibility.Benefiting from the well-designed electrodes,the assembled flexible fiber-shaped ZIB delivers a high specific capacity of 281.5 m Ah g^(-1) at 0.25 A g^(-1) and displays excellent cycling stability over 400 cycles.Moreover,the wet-spun fiber-shaped ZIBs achieve ultrahigh gravimetric and volumetric energy densities of 47.3 Wh kg^(-1) and 131.3 m Wh cm^(-3),respectively,based on both cathode and anode and maintain favorable stability even after 4000 bending cycles.This work offers a new concept design of 1D flexible ZIBs that can be potentially incorporated into commercial textiles for wearable and portable electronics.

Cellulose Nanopaper:Fabrication,Functionalization,and Applications

Cellulose nanopaper has shown great potential in diverse fields including optoelectronic devices,food packaging,biomedical application,and so forth,owing to their various advantages such as good flexibility,tunable light transmittance,high thermal stability,low thermal expansion coefficient,and superior mechanical properties.Herein,recent progress on the fabrication and applications of cellulose nanopaper is summarized and discussed based on the analyses of the latest studies.We begin with a brief introduction of the three types of nanocellulose:cellulose nanocrystals,cellulose nanofibrils and bacterial cellulose,recapitulating their differences in preparation and properties.Then,the main preparation methods of cellulose nanopaper including filtration method and casting method as well as the newly developed technology are systematically elaborated and compared.Furthermore,the advanced applications of cellulose nanopaper including energy storage,electronic devices,water treatment,and high-performance packaging materials were highlighted.Finally,the prospects and ongoing challenges of cellulose nanopaper were summarized.

Research progress of nanocellulose for electrochemical energy storage:A review

Recently, in response to the major challenges in energy development and environmental issues, tremendous efforts are being devoted to developing electrochemical energy storage devices based on green sustainable resources. As a class of green materials, nanocellulose(NC) has received extensive attention. In this review, we summarize the research progress of NC derived materials in electrochemical energy storage. Specifically, we first introduce various synthesis methods based on NC and the pretreatment process to increase the conductivity. Then we focus on the specific application of NC in electrochemical energy storage devices. Finally, we summarize the previously reported work and put forward views on the further development of NC in the field of electrochemical energy storage.

State of the Art Manufacturing and Engineering of Nanocellulose: A Review of Available Data and Industrial Applications

This review provides a critical overview of the recent methods and processes developed for the production of cellulose nanoparticles with controlled morphology, structure and properties, and also sums up (1) the processes for the chemical modifications of these particles in order to prevent their re-aggregation during spray-drying procedures and to increase their reactivity, (2) the recent processes involved in the production of nanostructured biomaterials and composites. The structural and physical properties of those nanocelluloses, combined with their biodegradability, make them materials of choice in the very promising area of nanotechnology, likely subject to major commercial successes in the context of green chemistry. With a prospective and pioneering approach to the subject matter, various laboratories involved in this domain have developed bio-products now almost suitable to industrial applications;although some important steps remain to be overcome, those are worth been reviewed and supplemented. At this stage, several pilot units and demonstration plants have been built to improve, optimize and scale-up the processes developed at laboratory scale. Industrial reactors with suitable environment and modern control equipment are to be expected within that context. This review shall bring the suitable processing dimension that may be needed now, given the numerous reviews outlining the product potential attributes. An abundant literature database, close to 250 publications and patents, is provided, consolidating the various research and more practical angles.

Review of Cellulose Smart Material: Biomass Conversion Process and Progress on Cellulose-Based Electroactive Paper

Cellulose is a renewable biomass material and natural polymer which is abundantly available on Earth,and includes agricultural wastes,forestry residues,and woody materials.The excellent and smart characteristics of cellulose materials,such as lightweight,biocompatibility,biodegradability,high mechanical strength/stiffness and low thermal expansibility,have made cellulose a highpotential material for various industry applications.Cellulose has recently been discovered as a smart material in the electroactive polymers family which carries the name of cellulose-based electroactive paper(EAPap).The shear piezoelectricity in cellulose polymers is able to induce large displacement output,low actuation voltage,and low power consumption in the application of biomimetic sensors/actuators and electromechanical system.The present study provides an overview of biomass pretreatment from various lignocellulosic cellulose(LC)resources and nanocellulose production via TEMPO-mediated oxidation reaction,followed by the production of different types of EAPap versus its performance,and lastly the applications of EAPap in different areas and industries.Specifically,LC biomass consists mainly of cellulose having a small content of hemicelluloses and lignins which form a defensive inner structure against the degradation of plant cell wall.Thus,selective approaches are discussed to ensure proper extraction of cellulosic fibers from complex biomass for further minimization to nano-dimensions.In addition,a comprehensive review of the development of cellulose-based EAPap as well as fabrication,characterization,performance enhancement and applications of EAPap devices are discussed herein.

Nanocellulose isolation characterization and applications:a journey from non-remedial to biomedical claims

Cellulose is a renewable,biodegradable,ecofriendly and sustainable biomaterial.Global market of nanocellulose is comprehensively very high due to its utility.Extraction of nanocellulose from bacteria and plant results in different morphology and size of nanocellulose.Biocompatibility,mechanical strength,biofabrication,crystallinity,high surface area per unit mass,hydrophilicity,porosity,transparency and non-toxicity of bacterial cellulose make it more attractive.The extravagant nanoscaled three-dimensional network of cellulosic structures possess extraordinary properties for biomedical application,evidencing its usage in skin therapy,cardiovascular implants,cartilage meniscus implants,tissue engineering,bone tissue and neural implants,wound care products,drug delivery agents,tablet modification,tissue engineered urinary conduits,and synthesis of artificial cornea.Hence due to potential benefits associated with nanocellulose effective and efficient techniques are required for the isolation of nanocellulose that should be economical,ecofriendly and non-toxic.

Progress in Nanocellulose Preparation and Application

Nanocellulose is a biodegradable, renewable, nonmeltable polymeric material that is insoluble in most solvents due to hydrogen bonding and crystallinity. Nanocellulose has attracted considerable attention in recent decades owing to its environmental friendliness, wide availability, good biocompatibility, high crystallinity, and high Young's modulus. This review presents the recent achievements in preparation and applications of nanocellulose, including a discussion of the advantages and disadvantages of various preparation methods and a summary of the applications of nanocellulose in composite materials research. Finally, we examine the mounting evidence of more widespread potential applications of nanocellulose.

Bacterial nanocellulose production and biomedical applications

Bacterial nanocellulose(BNC)is a homopolymer ofβ-1,4 linked glycose,which is synthesized by Acetobacter using simple culturing methods to allow inexpensive and environmentally friendly small-and large-scale production.Depending on the growth media and types of fermentation methods,ultra-pure cellulose can be obtained with different physio-chemical characteristics.Upon biosynthesis,bacterial cellulose is assembled in the medium into a nanostructured network of glucan polymers that are semitransparent,mechanically highly resistant,but soft and elastic,and with a high capacity to store water and exchange gasses.BNC,generally recognized as safe as well as one of the most biocompatible materials,has been found numerous medical applications in wound dressing,drug delivery systems,and implants of heart valves,blood vessels,tympanic membranes,bones,teeth,cartilages,cornea,and urinary tracts.

Nanocomposite membranes with high-charge and size-screened phosphorylated nanocellulose fibrils for CO_(2)separation

In this study,cellulose nanofibrils(CNF)of high charge(H-P-CNF)and screened size(H-P-CNF-S)were fabricated by increasing the charge of phosphorylated cellulose nanofibrils(P-CNFs)during the pre-treatment step of CNF production.Results show that the H-P-CNF have a significantly higher charge(3.41 mmol g^(-1))compared with P-CNF(1.86 mmol g^(-1)).Centrifugation of H-P-CNF gave a supernatant with higher charge(5.4 mmol g^(-1))and a reduced size(H-P-CNF-S).These tailored nanocelluloses were added to polyvinyl alcohol(PVA)solutions and the suspensions were successfully coated on porous polysulfone(PSf)supports to produce thin-film nanocomposite membranes.The humid mixed gas permeation tests show that CO_(2)permeability increases for membranes with the addition of H-P-CNF-S by 52%and 160%,compared with the P-CNF/PVA membrane and neat PVA membrane,respectively.