Application Of Cellulose Nanofibers Research Articles

Solvent-induced micro-morphological structure strategy regulating the interfacial mechanism of carbon fiber reinforced composites

Current research on cellulose nanofiber (CNF) in the field of mechanical properties mainly involves the direct application of CNF and simple composites with other materials. The relationship between the morphology and structure of CNF-based materials and the target functions of composites has rarely been explored. Here, as an example of carbon fiber reinforced composites (CFRP), CNF-based organic coating with different micromorphological structures was fabricated on the surface of carbon fiber (CF) by regulating the solvent ratio of binary solvents (deionized water/ethanol). The trends of their chemical components and microstructures were investigated, as well as their effects on the interfacial bonding performance of CFRP. The results indicated that an increase in the ratio of deionized water in the binary solvent led to a smaller raised structure with poor adhesion and an increase in coating uniformity on the organic coating, which would directly affect the tensile strength (TS) of the CF and the interlaminar shear strength (ILSS) of CFRP. This research presents important insights into the mechanism of composite interfaces based on the differences in the micro-morphological structures of materials.

Cellulose nanofibers as effective binders for activated biochar-derived high-performance supercapacitors

Traditional hydrophobic binders can limit supercapacitors' performance by impeding ion accessibility. Herein, we demonstrate the potential of plant-derived environmentally friendly Cellulose Nanofibers (CNF) as binders for biochar (BN-Ac)-based supercapacitors. The CNF binder retains BN-Ac's micropores and improves wettability, while the Polyvinylidene Fluoride (PVDF) binder fills micropores and hinders ion-conductive pathways. The as-synthesized BN-Ac/CNF exhibits a capacitance of 268.4 F g−1 at 5 A g−1, which is 1.4 times higher than that of BN-Ac/PVDF. In addition, the energy density improves from 4.6 to 5.7 Wh kg−1 at 2.1 and 2.5 kW kg−1 power, respectively, for replacing PVDF with CNF. More importantly, BN-Ac/CNF shows outstanding capacitance retention of 96.2 % after 10,000 charge/discharge cycles. The improved wettability and reduced bulk electrolyte resistance by hydrophilic CNF binders are responsible for the electrode's high capacitance. Concurrently, this study showcases a facile strategy for improving supercapacitor performance and a green application of CNF in energy devices.

Cellulose nanofibers prepared from pulp through ultrasound treatment followed semi-dry esterification and their application for transparent and anti-fingerprint coating

In order to facilitate nano-fibrillation via ultrasound to prepare cellulose nanofibers (CNFs) from flocculent pulp, a semi-dry esterification was carried out to modify the pulp with maleic anhydride. Small amount water addition improves mixing of the reactants and increases extent of esterification. The modification significantly enhances nano-fibrillation of the pulp in subsequent ultrasound treatment. CNFs with about 200–400 nm in length and about 20–25 nm in width are obtained from the esterified pulp. CNFs coating, prepared by casting CNFs aqueous dispersion on glass slide, gives rise to about 4% increase in transmittance of the slide and improves anti-fingerprint property of the slide. The results of this study provide a solution for production of CNFs from flocculent pulps and demonstrate the potential application of CNFs for anti-reflection and anti-fingerprint coatings.

Hydrothermal synthesis of nanocellulose-based fluorescent hydrogel for mercury ion detection

Cellulose nanofibers (CNF) possess excellent hydrophilicity, biocompatibility, high specific surface area and biodegradability, and the application of CNF to fluorescent hydrogels is one of the hotspots in the field of functional hydrogels. However, the rapid and efficient preparation of them remains a challenge, and it is necessary to explore its application in the detection of heavy metal ions. In this study, a hydrothermal method was adopted to investigate the one-pot synthesis of CNF-based fluorescent hydrogel (CFH) for mercury ion detection, which synchronously enabled CFH formation and in-situ carbon quantum dots synthesis. The as-prepared CFH had a complete 3D network structure, and epichlorohydrin showed positive effects on the mechanical properties of CFH. Moreover, excellent fluorescence performance can be achieved through regulating the synthesis process of carbon quantum dots. The as-prepared CFH showed different quenching effects in the Hg2+ solution with different concentrations, and the fluorescence intensity of CFH was closely related to the Hg2+ concentration in the range of 0–300 mmol/L, which showed great development potential and prospects in the fields of fluorescence probes on Hg2+ sensing and detection. This study provided a promising method for the rapid preparation of biocompatible and environment-friendly fluorescent hydrogel probes and ion detection materials.

Enhancement of impact properties of CFRP by inserting the non-hydrophobized cellulose nanofiber dispersion layer using an aqueous solution of epoxy resin

Cellulose nanofibers (CNFs) are environmental-friendly nanofiller with high strength and lightweight. To improve the impact properties of carbon fiber reinforced plastics (CFRPs), the application of CNF is expected. However, hydrophobic treatment was unavoidable due to its hydrophilicity. In this study, by adopting an aqueous solution of epoxy resin, the CFRP with CNF dispersion layer was fabricated. From the instrumented Charpy test, it was revealed that the waveform of impact force has two peaks, and the second peak was enlarged by the CNF dispersion layer. As a result, Charpy impact value of the CFRP was increased up to 6%. Highlights A novel method to enhance the impact properties of carbon fiber reinforced plastic (CFRP) by using cellulose nanofiber (CNF) was developed. By dispersing CNFs in an aqueous epoxy solution, hydrophobic treatment was eliminated. Inserting the CNF dispersion layer increased the Charpy impact value of CFRP up to 6%.

Performance evaluation of cellulose nanofiber reinforced polymer composites

In recent years, cellulose nanofiber (CNF) has become an avidly researched material in cutting edge research fields involving prominent researchers, both in academia and industry. This has become an exciting time reaching beyond just scientific curiosity as CNF is beginning to enter various marketplaces. CNF shows unique and potentially useful features, which includes abundance, high specific surface area, renewability, high strength, eco-friendliness and high crystallinity. It is an excellent material for polymer reinforcement. Many studies have been conducted to understand the effects of CNF as a filler in polymer composites. Interestingly, most CNF polymer composites have shown a better mechanical performance compared to the neat base polymer. Thus, this enhances the application of CNF into reinforced polymer composites in several industries such as automotive, packaging, medical implant, electronics, building material and paper. Therefore, in this review, the performances of CNF polymer composites are carefully evaluated. Beyond that, several factors influencing the performance of these composites are discussed.

Development and characterization of carboxymethyl cellulose based probiotic nanocomposite film containing cellulose nanofiber and inulin for chicken fillet shelf life extension

Bioactive packaging is an alternative new technology for preserving the quality and safety of food products with providing health benefits. In this way, the Lactobacillus plantarum, cellulose nanofiber (CNF) and inulin incorporated carboxymethyl cellulose (CMC) based probiotic nanocomposite film was prepared. The fabricated film samples were characterized by FTIR, FE-SEM, XRD and DSC analyses, that the obtained results indicated the good compatibility between CMC, CNF, and inulin. As a result, the CMC-based probiotic films containing CNF and inulin exhibited satisfactory water barrier and mechanical properties. Additionally, the viability of probiotic bacteria in the CMC-based films was significantly (p < 0.05) increased (36%) by addition of inulin as a prebiotic ingredient during storage time. Probiotic film sample showed antibacterial activity against nine pathogens and also extended the chicken fillet shelf life when wrapped on the meat. In conclusion, the application of CNF and inulin incorporated CMC-based probiotic nanocomposite film as a bioactive food packaging system opens up a new horizon for improving the shelf life of food products and providing the health benefits for consumers.

Cellulose Nanofibers Isolated from the Cuscuta Reflexa Plant as a Green Reinforcement of Natural Rubber.

In the present work, we used the steam explosion method for the isolation of cellulose nanofiber (CNF) from Cuscuta reflexa, a parasitic plant commonly seen in Kerala and we evaluated its reinforcing efficiency in natural rubber (NR). Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Thermogravimetric analysis (TGA) techniques indicated that type I cellulose nanofibers, with diameter: 10–30 nm and a 67% crystallinity index were obtained by the proposed method. The results showed that application of CNF in NR based nanocomposites resulted in significant improvement of their processing and performance properties. It was observed that the tensile strength and tear strength of NR/CNF nanocomposites are found to be a maximum at 2 phr CNF loading, which corresponds with the studies of equilibrium swelling behavior. Dynamic mechanical analysis, thermogravimetric analysis, and morphological studies of tensile fractured samples also confirm that CNF isolated from Cuscuta reflexa plant can be considered as a promising green reinforcement for rubbers.

Application of enzyme-mediated cellulose nanofibers from lemongrass waste for the controlled release of anticancer drugs.

In the present study, an application of cellulose nanofibers has been established for the controlled release of an anticancer drug, i.e., camptothecin. The camptothecin is known for its antitumor activity. However, it has certain limitations like instability, low solubility in aqueous solution, and biological fluids. Firstly, the camptothecin was encapsulated into the cellulose nanofiber complex by adjusting the composition ratio of cellulose nanofibers-camptothecin, i.e., 10:3, 10:5, and 10:7. In the 10:3 composition ratio of cellulose nanofibers, camptothecin showed the highest encapsulation efficiency, i.e., 65.28%. The binding of camptothecin with cellulose nanofibers was confirmed by FT-IR analysis. Also, the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm studies demonstrate physical adsorption of camptothecin onto the homogeneous as well as the heterogeneous surface of cellulose nanofibers. Further, the controlled and extended-release profile was observed at different physiological pH, and different kinetics models were used to understand the drug release mechanism. The highest correlation in all pH conditions was obtained in Korsmeyer-Peppas with R2 value = 0.93 (pH1.2), 0.89 (pH6.8), and 0.97 (pH7.4), whereas in Higuchi model, R2 value = 0.89 (pH1.2), 0.91 (pH6.8), and 0.98 (pH7.4), suggesting the release of a drug via a diffusion mechanism. Hence, the results established that enzyme-mediated cellulose nanofibers may also be an optimal carrier for the controlled drug release formulation without any chemical excipients.

Cellulose nanofiber assisted hydrothermal synthesis of Ni-rich cathode materials with high binding particles for lithium-ion batteries

Although the Ni-rich cathodes materials are so attractive in lithium batteries for its high capacity and costs; the drawback of structural corruption caused by electrolyte corrosion still exist as a main problem, which retards its commercial application. This paper demonstrated a cellulose nanofiber (CNF) assisted hydrothermal synthesis of Li[Ni0.8Co0.1Mn0.1]O2 with tight binding of primary particles, thus partially alleviated the corrosion of electrolyte on Li[Ni0.8Co0.1Mn0.1]O2 during the charging and discharging process. The as prepared CNF assisted hydrothermal synthesized Li[Ni0.8Co0.1Mn0.1]O2 delivers reversible capacity of 145.1mAh g−1 after 50 cycles at 0.5C, which is 10.3% higher than the bare Li[Ni0.8Co0.1Mn0.1]O2 cathodes. Adding CNF in the hydrothermal synthesis process, not only templated the growth of precursor, but also enhanced the binding force of the primary Li[Ni0.8Co0.1Mn0.1]O2 particles when the precursor is calcined. The application of CNF in preparation of Li[Ni0.8Co0.1Mn0.1]O2 is considerable. It suggests a simple strategy to improving the synthesis and performance of Ni-rich cathode materials, which can also be applied to other Li-ion cathode materials.

Efficient fractionation of cellulose nanofibers using spiral microchannel

Plant fiber isolated cellulose nanofibers (CNFs) are the materials with excellent mechanical properties. However, application of CNFs in polymer reinforcement is normally unsatisfactory due to its intertwined size distribution. Efforts to produce uniform sized CNFs have yet to be studied. In present work, spiral microchannel was used to fractionate CNFs based on the balance between inertial lift force (FL) and Dean drag force (FD) exerted on CNFs. The results showed that the smaller length of CNFs equilibrated near the inner microchannel while the larger length of CNFs occupied the equilibrium position away from the inner wall. With the increase of flowrates from 50 to 220 μL/min, fractionation efficiency between inner and middle outlet (EIM) of spiral microchannel A with larger radius curvature (R) from 5 to 15 mm increased from 0 to 75.4%. However, stronger Dean flow attributing to decrease of R (3 mm to 10 mm) of single spiral microchannel B enabled satisfactory fractionation efficiency of 70.9% at flowrate of 90 μL/min. Moreover, the fractionation efficiency of double spiral microchannel with twice as length as microchannel A and three times as length as microchannel B was lower than that of single spiral microchannel at flowrate lower than 90 μL/min. Furthermore, this study exhibited a versatile and simple method for CNFs fractionation with high fractionation efficiency.

Tuning of size and properties of cellulose nanofibers isolated from sugarcane bagasse by endoglucanase-assisted mechanical grinding

This study explores the possibility of producing tunable cellulose nanofibers (CNFs) with a wide range of size and properties from sugarcane bagasse in an energy-efficient manner, which is very meaningful for specific application of CNFs. The bleached bagasse kraft pulp was subjected to endoglucanase pretreatment with a wide range of enzyme dosage followed by mechanical grinding to obtain size-tunable CNFs. The size distribution and structural characteristics of CNFs, energy consumed during the CNF production process, and properties of CNF films were systematically investigated as a function of the enzyme dosage applied in the pretreatment. The results showed that endoglucanase-assisted mechanical grinding was able to produce CNFs with controllable length (298–4500 nm) and diameter (9–26 nm), meanwhile improving CNF yield and energy-efficiency. The controllable range of CNF length was extremely wide based on our best knowledge. The optical performance and mechanical properties of the prepared CNF films could be effectively tuned by regulating the structural characteristics of the CNFs. Moreover, all the as-prepared CNFs retained high thermal stability. The tailor-made CNFs from sugarcane bagasse are expected to provide compatibility with various CNF-related applications.

Genomic and metabolic analysis of Komagataeibacter xylinus DSM 2325 producing bacterial cellulose nanofiber.

Bacterial cellulose nanofiber (CNF) is a polymer with a wide range of potential industrial applications. Several Komagataeibacter species, including Komagataeibacter xylinus as a model organism, produce CNF. However, the industrial application of CNF has been hampered by inefficient CNF production, necessitating metabolic engineering for the enhanced CNF production. Here, we present complete genome sequence and a genome-scale metabolic model KxyMBEL1810 of K. xylinus DSM 2325 for metabolic engineering applications. Genome analysis of this bacterium revealed that a set of genes associated with CNF biosynthesis and regulation were present in this bacterium, which were also conserved in another six representative Komagataeibacter species having complete genome information. To better understand the metabolic characteristics of K. xylinus DSM 2325, KxyMBEL1810 was reconstructed using genome annotation data, relevant computational resources and experimental growth data generated in this study. Random sampling and correlation analysis of the KxyMBEL1810 predicted pgi and gnd genes as novel overexpression targets for the enhanced CNF production. Among engineered K. xylinus strains individually overexpressing heterologous pgi and gnd genes, either from Escherichia coli or Corynebacterium glutamicum, batch fermentation of a strain overexpressing the E. coli pgi gene produced 3.15 g/L of CNF in a complex medium containing glucose, which was the best CNF concentration achieved in this study, and 115.8% higher than that (1.46 g/L) obtained from the control strain. Genome sequence data and KxyMBEL1810 generated in this study should be useful resources for metabolic engineering of K. xylinus for the enhanced CNF production.

A Comparative Study on the Characterization of Nanofibers with Cellulose I, I/II, and II Polymorphs from Wood.

Polymorphic changes in cellulose nanofibers (CNFs) are closely related to their properties and applications, and it is of interest to investigate how polymorphic changes influence their properties. A comparative study on the properties of CNFs with cellulose I, I/II, and II polymorphs from wood was conducted herein. CNFs were obtained by chemical extraction combined with a simple and efficient mechanical treatment (one pass through a grinder). This process resulted in a relatively high yield of 80–85% after a simple grinding treatment. The polymorphic changes in the CNFs and the chemical composition, morphology, tensile performances, and thermal properties were systematically characterized and compared. The X-ray diffraction and FTIR analyses verified the existence of three types of purified pulps and CNFs with cellulose I, cellulose I/II, and cellulose II polymorphs (CNF-I, CNF-I/II, CNF-II). Morphological observations presented that these three types of CNFs all exhibited high aspect ratios and entangled structures. Tensile testing showed that the CNF films all exhibited high tensile strengths, and the fracture strains of the CNF-I/II (11.8%) and CNF-II (13.0%) films were noticeably increased compared to those of the CNF-I film (6.0%). If CNF-II is used as reinforcing material, its larger fracture strain can improve the mechanical performance of the CNF composites, such as fracture toughness and impact strength. In addition, CNF-I, CNF-I/II, and CNF-II films showed very low thermal expansion in the range 20–150 °C, with the coefficient of thermal expansion values of 9.4, 17.1, and 17.3 ppm/K, respectively. Thermogravimetric analysis (TGA) revealed that the degradation temperature of CNF-I and CNF-II was greater than that of CNF-I/II, which was likely due to increased α-cellulose content. This comparative study of the characterization of CNF-I, CNF-I/II, and CNF-II provides a theoretical basis for the application of CNFs with different polymorphs and could broaden the applications of CNFs.

Development and Potential Application of Advanced Functional Materials in the Oil Field

The oil and gas industry places higher demands for new technologies and new materials. Advanced functional materials show broad application prospects in the oil field. Technological advances in the oil and gas sector are inseparable from the development and application of advanced functional materials. Through literature research, patent search analysis, expert consultation, some advanced functional materials with potential application in the oil field are sorted out, in order to provide inspiration and new ideas for improving the development of the oil and gas drilling technology. The nanomaterials dispersion and nanocomposites films are two of the most accessible ways to apply nanomaterials in the oil field. The cellulose nanofibers (CNF) and the diamond-like carbon (DLC) nanocomposites films would provide inspiration for the oil field chemistry and protection of downhole tools. The application of CNF and DLC nanocomposites could provide innovative ideas, research and foundation for the future development of the oil and gas drilling technology, and contribute to achieving a major technological breakthrough and improve the overall level of the oil and gas drilling technology.

Enhancement of mechanical properties of CFRP manufactured by using electro-activated deposition resin molding method with the application of CNF without hydrophobic treatment

Cellulose nanofiber (CNF) is high strength and lightweight, additionally, it is produced by sustainable natural resources such as wood. Therefore, it has been reported the mechanical properties of CFRP can be improved by dispersing CNF in the matrix. However, as CNF is hydrophilic, a hydrophobic treatment was applied in many previous studies. For efficient CFRP manufacturing, the authors have developed an electrochemical resin molding method by using aqueous electro-activated deposition which contains the polymer having an epoxy group. In this method, the carbon fiber fabric is immersed in the electro-activated deposition solution and energized, epoxy resin is precipitated around the carbon fiber and impregnated. In this study, shortly after electro-activated deposition, CNF without a hydrophobic treatment was applied to the surface of the resin-impregnated carbon fiber fabric. The mechanical properties of CFRP could be enhanced, and optimum weight fraction of CNF was revealed.

Cell interactions and cytotoxic studies of cellulose nanofibers from Curauá natural fibers

Cellulose nanofibers (CNF) were isolated from Curauá fibers (Ananas erectifolius L. B. Smith) through a mechanical grinder preceded by mild chemical treatment. Morphology and surface characteristics of the fibers were followed until it reaches the nanoscale as long and flexible nanofibers. In aqueous suspensions, SAXS techniques revealed that such nanofibers present a twisted ribbon structure while rheological measurements demonstrate its high viscosity and a thixotropic behavior. These characteristics suggests the potential application of CNF in biomedical field, which, in turn, stimulates the toxicological studies of such materials. The obtained materials do not show any sign of cytotoxicity by direct or indirect assays for cell viability and cell morphology using Vero cells. Moreover, during the adhesion test, the cells demonstrated higher affinity to the CNF surface. It can be related to its surface properties and its obtaining conditions, which did not use any hazardous chemicals.

Cellulose nanofibers from banana peels as a Pickering emulsifier: High-energy emulsification processes

Cellulose nanofibers (CNFs) from banana peels was evaluated as promising stabilizer for oil-in-water emulsions. CNFs were treated using ultrasound and high-pressure homogenizer. Changes on the size, crystallinity index and zeta potential of CNFs were associated with the intense effects of cavitation phenomenon and shear forces promoted by mechanical treatments. CNFs-stabilized emulsions were produced under the same process conditions as the particles. Coalescence phenomenon was observed in the emulsions produced using high-pressure homogenizer, whereas droplets flocculation occurred in emulsions processed by ultrasound. In the latter, coalescence stability was associated with effects of cavitation forces acting on the CNFs breakup. Thus, smaller droplets created during the ultrasonication process could be recovered by particles that acted as an effective barrier against droplets coalescence. Our results improved understanding about the relationship between the choice of emulsification process and their effects on the CNFs properties influencing the potential application of CNFs as a food emulsifier.

Comparison of mechanical reinforcement effects of cellulose nanocrystal, cellulose nanofiber, and microfibrillated cellulose in starch composites

In this work, cellulose nanocrystal (CNC), cellulose nanofiber (CNF), and microfibrillated cellulose (MFC) are used to reinforce starch to obtain high‐performance starch nanocomposites by film casting. The results show that MFC is a highly efficient filler to reinforce starch compared with CNC and CNF. Largely enhanced tensile strength and modulus have been achieved (3.1 MPa, 146.7 MPa for pure starch, 10.6 MPa, 757.4 MPa for starch/MFC composite). Moreover, starch/nanocellulose nanocomposites prepared in this work exhibit excellent transparency and thermostability. Most importantly, the results of sizing performances of the nanocomposites reveal that adding of 3 wt% MFC in starch has obviously enhanced the adhesiveness of sizes to fibers. Our work may help lay a foundation for preparation of high‐performance starch/MFC sizing agents, and contribute to largely expanding the industrial application of CNFs. POLYM. COMPOS., 40:E365–E372, 2019. © 2017 Society of Plastics Engineers

Homogeneous Dispersion of Cellulose Nanofibers in Waterborne Acrylic Coatings with Improved Properties and Unreduced Transparency

Cellulose nanocrystal has been widely used as a reinforcement filler in waterborne coatings, but the application of cellulose nanofiber (CNF) as a filler is difficult because of inhomogeneous dispersion. Herein, a facile and effective strategy to improve the dispersion of CNFs in the polymer matrix by mixing with γ-aminopropyltriethoxysilane (APS) is presented. The APS dosages 0.08–0.48 wt % to 0.3 wt % CNFs were investigated, and the dosage 0.16% was found to achieve a superior stability of CNFs in the aqueous solution. The APS(0.16%)-modified CNFs were then incorporated and demonstrated distributing uniformly in the waterborne acrylic coating. The as-prepared coatings retain high light transmittance around 90%, and display improved mechanical properties. The composite coatings show a maximum 500% improvement in Young’s modulus, two-level improvement in hardness, and 35% reduction in abrasion loss as compared with those of neat coating. These results reveal that APS modification induces the homogeneous d...