Food packaging is becoming popular as the consumption of ready-to-eat food products rises.Easyto-use,non-biodegradable plastic packaging is commonly used in food packaging,contributing to the deteriorating environment...Food packaging is becoming popular as the consumption of ready-to-eat food products rises.Easyto-use,non-biodegradable plastic packaging is commonly used in food packaging,contributing to the deteriorating environmental situation.This issue increases the concern for the environment and encourages the usage of alternative materials.Cellulose nanofibrils(CNF)are abundant and biodegradable,which makes them ideal candidates to replace plastic coatings.The ability to form H-bonds between the hydroxyl groups makes coated paper with CNF have good strength,but poor barrier properties.The barrier properties can be improved by grafting DMAEMA or HEMA onto CNF(CNF-g-PDMAEMA and CNF-g-PHEMA,respectively).Thus,the objective of this study was to modify CNF chemically to enhance the barrier properties of the food packaging paper.It was found that paper coated with CNFg-PDMAEMA and CNF-g-PHEMA exhibited improvements in mechanical and barrier properties while maintaining the desired viscosity for the coating process.The water contact angle increased for paper coated with CNF-g-PHEMA and CNF-g-PDMAEMA,reaching a maximum of 97.51°and 92.58°,respectively with the decreasing Cobb_(60) values by 49% and 11%.The oil absorption was also reduced for both coated papers compared to the blank paper.Mechanical properties improved,as indicated by a 3% increase in tensile strength for paper coated with CNF-g-PHEMA and a 5% for paper coated with CNF-g-PDMAEMA.The results indicated significant potential for the application of modified CNF in coatings for food packaging paper.Noteworthy,the grafting process should be improved to enhance the mechanical and barrier properties of the coated paper.展开更多
As the rapid development of portable and wearable devices,different electromagnetic interference(EMI)shielding materials with high efficiency have been desired to eliminate the resulting radiation pollution.However,li...As the rapid development of portable and wearable devices,different electromagnetic interference(EMI)shielding materials with high efficiency have been desired to eliminate the resulting radiation pollution.However,limited EMI shielding materials are successfully used in practical applications,due to the heavy thickness and absence of sufficient strength or flexibility.Herein,an ultrathin and flexible carbon nanotubes/MXene/cellulose nanofibrils composite paper with gradient and sandwich structure is constructed for EMI shielding application via a facile alternating vacuum-assisted filtration process.The composite paper exhibits outstanding mechanical properties with a tensile strength of 97.9±5.0 MPa and a fracture strain of 4.6±0.2%.Particularly,the paper shows a high electrical conductivity of 2506.6 S m?1 and EMI shielding effectiveness(EMI SE)of 38.4 dB due to the sandwich structure in improving EMI SE,and the gradient structure on regulating the contributions from reflection and absorption.This strategy is of great significance in fabricating ultrathin and flexible composite paper for highly efficient EMI shielding performance and in broadening the practical applications of MXene-based composite materials.展开更多
Composite nanofiber membranes based on biodegradable poly(lactic acid)(PLA) and cellulose nanofibrils(CNF) were produced via electrospinning. The influence of CNF content on the morphology, thermal properties, and mec...Composite nanofiber membranes based on biodegradable poly(lactic acid)(PLA) and cellulose nanofibrils(CNF) were produced via electrospinning. The influence of CNF content on the morphology, thermal properties, and mechanical properties of PLA/CNF composite nanofiber membranes were characterized by field scanning electron microscopy(FE-SEM), differential scanning calorimetry(DSC), thermogravimetric analysis(TGA), and dynamic mechanical analysis(DMA), respectively. The results show that the PLA/CNF composite nanofibers with smooth, free-bead surface can be successfully fabricated with various CNF contents. The introduction of CNF is an effective approach to improve the crystalline ability, thermal stability and mechanical properties for PLA/CNF composite fibers. The Young's moduli and tensile strength of the PLA/CNF composite nanofiber reach 106.6 MPa and 2.7 MPa when the CNF content is 3%, respectively, which are one times higher and 1.5 times than those of pure PLA nanofiber. Additionally, the water contact angle of PLA/CNF composite nanofiber membranes decreases with the increase of the CNF loading, resulting in the enhancement of their hydrophilicity.展开更多
The design of flexible polymeric films with internal porous structures has received increasing attention in low dielectric applications.The highly porous metal-organic frameworks(MOFs)of[Cu_(3)(BTC)_(2)]_(n)(BTC=benze...The design of flexible polymeric films with internal porous structures has received increasing attention in low dielectric applications.The highly porous metal-organic frameworks(MOFs)of[Cu_(3)(BTC)_(2)]_(n)(BTC=benzene-1,3,5-tricarboxylate)were introduced into aramid nanofibers(ANF)matrix by using carboxylated cellulose nanofibrils(CNF)as carriers to obtain strong,flexible,and ultra-low dielectric films.The well-dispersed“flowers-branch”like CNF@CuBTC through in-situ growth of CuBTC on CNF surface endowed the ANF/CNF@Cu BTC films with excellent thermal stability,mechanical integrity and low dielectric properties.Besides,the flexible dielectric films exhibited superior ultraviolet(UV)resistance,lower coefficient of thermal expansion(4.28×10^(-5)℃^(-1))and increased water contact angle(83.81°).More interestingly,the removal of vip molecules from the ANF/CNF@CuBTC films according to the vacuum heat treatment(VHT)process significantly improved their dielectric response.The specific surface areas of the composite films after VHT increased obviously,and the dielectric constant and dielectric loss tangent decreased to the expected 1.8-2.2 and 0.001-0.03 at 100 MHz,respectively.Consequently,such designable ultra-low dielectric films with high flexibility play an incredible significance in applications of microelectronics under large deformation conditions,especially in flexible/wearable devices at the arrival of 5 G era.展开更多
TiO2 nanofibrils were prepared within the pores of alumina template membrane by use of sol-gel chemistry. The TiO2 nanofibrils have good crystallinity and size. There is agglomeration free among the particulates of ...TiO2 nanofibrils were prepared within the pores of alumina template membrane by use of sol-gel chemistry. The TiO2 nanofibrils have good crystallinity and size. There is agglomeration free among the particulates of TiO2 and the fibrils show high catalytic activity.展开更多
Two-dimensional covalent organic framework nanosheets(CONs)with ultrathin thickness and porous crystalline nature show substantial potential as novel membrane materials.However,bringing CONs materials into flexible me...Two-dimensional covalent organic framework nanosheets(CONs)with ultrathin thickness and porous crystalline nature show substantial potential as novel membrane materials.However,bringing CONs materials into flexible membrane form is a monumental challenge due to the limitation of weak interactions among CONs.Herein,one-dimensional silk nanofibrils(SNFs)from silkworm cocoon are designed as the nanobinder to link sulfonated CON(SCON)into robust SCON-based membrane through vacuum-filtration method.Ultrathin and large lateral-sized SCONs are synthesized via bottom-up interface-confined synthesis approach.Benefiting from high length-diameter ratio of SNF and rich functional groups in both SNF and SCON,two-dimensional(2D)SCONs are effectively connected together by physical entanglement and strong H-bond interactions.The resultant SCON/SNF membrane displays dense structure,high mechanical integrity and good stability.Importantly,the rigid porous nanochannels of SCON,high-concentration-SO3H groups insides the pores and H-bonds at SCON-SNF interfaces impart SCON/SNF membrane high-rate proton transfer pathways.Consequently,a superior proton conductivity of 365 mS cm^(-1)is achieved at 80C and 100%RH by SCON/SNF membrane.This work offers a promising approach for connecting 2D CON materials into flexible membrane as high-performance solid electrolyte for hydrogen fuel cell and may be applied in membrane-related other fields.展开更多
The disinfection of waterborne pathogens from drinking water is extremely important for human health.Although countless efforts have been devoted for drinking water inactivation,challenges still exist in terms of rela...The disinfection of waterborne pathogens from drinking water is extremely important for human health.Although countless efforts have been devoted for drinking water inactivation,challenges still exist in terms of relative high energy consumption and complicated to implement and maintain.Here,silver nanoparticles anchoring wood carbon(Ag NPs/WC)membrane is developed as cost-effective,high flux,scalable filter for highly efficient electric field disinfection of water.Under electric field of 4 V voltage,the designed membrane achieved more than 5 log(99.999%)disinfection performance for different model bacteria,including Escherichia coli(E.coli),Enterococcus faecalis(E.faecalis),Salmonella enterica serovar Typhimirium(S.Typhimurium)and Bacillus subtilis(B.subtilis)with a high flux of 3.8 x 103 L m^(-2)h^(-1),extremely low energy consumption of 2 J L^(-1)m^(-2)and fantastic durability(7 days).The high disinfection performance of Ag NPs/WC membrane is attributed to the synergistic disinfection of carbon nanofibrils,Ag nanoparticles as well as the low tortuous structure of the channels in wood carbon.The Ag NPs/WC membrane presents a promising strategy for point-of-use drinking water electric field disinfection treatment.展开更多
Recently,cellulose nanofibril(CNF)has emerged as a promising,sustainable reinforcement with outstanding potential in material science.Owing to the properties of CNF,it has been explored in food,cosmetic,and pharmaceut...Recently,cellulose nanofibril(CNF)has emerged as a promising,sustainable reinforcement with outstanding potential in material science.Owing to the properties of CNF,it has been explored in food,cosmetic,and pharmaceutical applications,as well as in industrial applications such as paints,drill muds,packaging,and papermaking.The application of CNF in papermaking is expected to be implemented in the near future to broaden the commercial market of cellulose.Numerous studies and patents have reported on the manufacturing,properties,and applications of nanocellulose.This present paper focuses on the recent progresses in the application of CNF as a wet-end additive in papermaking.展开更多
Multicellular spheroids,which mimic the natural organ counterparts,allow the prospect of drug screening and regenerative medicine.However,their application is hampered by low processing efficiency or limited scale.Thi...Multicellular spheroids,which mimic the natural organ counterparts,allow the prospect of drug screening and regenerative medicine.However,their application is hampered by low processing efficiency or limited scale.This study introduces an efficient method to drive rapid multicellular spheroid formation by a cellulose nanofibril matrix.This matrix enables the facilitated growth of spheroids(within 48 h)through multiple cell assembly into size-controllable aggregates with well-organized physiological microstructure.The efficiency,dimension,and conformation of the as-formed spheroids depend on the concentration of extracellular nanofibrils,the number of assembled cells,and the heterogeneity of cell types.The above strategy allows the robust formation mechanism of compacted tumoroids and hepatocyte spheroids.展开更多
In this study, cellulose nanocrystals(CNC) with surface carboxylic groups were prepared from bleached softwood pulp by hydrolysis with concentrated citric acid at concentrations of 60 wt%~80 wt%. The solid residues fr...In this study, cellulose nanocrystals(CNC) with surface carboxylic groups were prepared from bleached softwood pulp by hydrolysis with concentrated citric acid at concentrations of 60 wt%~80 wt%. The solid residues from acid hydrolysis were collected for producing cellulose nanofibrils(CNF) via post high-pressure homogenization. Citric acid could be easily recovered after hydrolysis reactions through crystallization due to its low water solubility or through precipitation as a calcium salt followed by acidification. Several important properties of CNC and CNF, such as dimension, crystallinity, surface chemistry, thermal stability, were evaluated. Results showed that the obtained CNC and CNF surfaces contained carboxylic acid groups that facilitated functionalization and dispersion in aqueous processing. The recyclability of citric acid and the carboxylated CNC/CNF give the renewable cellulose nanomaterial huge potential for a wide range of industrial applications. Furthermore, the resultant CNC and CNF were used as reinforcing agents to make sodium carboxymethyl cellulose(CMC) films. Both CNC and CNF showed reinforcing effects in CMC composite films. The tensile strength of CMC films increased by 54.3% and 85.7% with 10 wt% inclusion of CNC and CNF, respectively. This study provides detailed information on carboxylated nanocellulose prepared by critic acid hydrolysis; a sustainable approach for the preparation of CNC/CNF is of significant importance for their various uses.展开更多
To improve the performance of polyurethane films,small amounts of cellulose nanofibrils(CNF)were physically blended with a waterborne polyurethane(WPU)emulsion,and then CNF/WPU composite films were prepared by cast-co...To improve the performance of polyurethane films,small amounts of cellulose nanofibrils(CNF)were physically blended with a waterborne polyurethane(WPU)emulsion,and then CNF/WPU composite films were prepared by cast-coating and drying.The particle size of the emulsions and the chemical structure,micromorphology,thermal stability,mechanical properties,and water resistance of the composite films were characterized using a Malvern laser particle size analyzer,Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),thermogravimetric analysis(TGA),an electronic strength machine,water contact angle analysis(WCA),and water absorption tests,respectively.The results showed that at a low CNF content of 0.3 wt%,the particle size of the WPU emulsion and chemical structure of the film did not change significantly.In addition,the tensile strength of the composite film increased by up to 108%compared to the neat WPU film,and the thermal stability and water resistance were slightly improved.The addition of CNF greatly enhanced the tensile strength while maintaining the other original properties of the WPU film,which may greatly improve the service life and tear resistance of commercial coatings in the future.展开更多
Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic characte...Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character.Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils,and a resin of poly(styrene-methyl-methacrylate-acrylic acid)used as water-based emulsion.Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions.The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension,leading to the co-precipitation of the composite material,which can be easily separated from the water phase.Composites with acrylic polymer/cellulose fibers in the proportions of 75:25,50:50 and 25:75 wt%were prepared.Composites were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),dynamic mechanical analysis(DMA)and water absorption tests.SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration,which led to superior mechanical properties.These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials.展开更多
In the current study poly(lactic acid)PLA composites with a 3 wt%and 5 wt%of nanofibrillated cellulose(NFC)were produced by 3D-printing method.An enzymatic pretreatment coupled with mechanical fibrillation in a twin s...In the current study poly(lactic acid)PLA composites with a 3 wt%and 5 wt%of nanofibrillated cellulose(NFC)were produced by 3D-printing method.An enzymatic pretreatment coupled with mechanical fibrillation in a twin screw extruder was used to produce high consistency NFC.Scanning electron microscopy(SEM)equipped with Fibermetric software,FASEP fiber length distribution analysis,Furrier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TGA),tensile tests,impact tests and differential scanning calorimetry were used to characterize NFC and PLA/NFC composites.The results of the fiber length and width measurements together with the results of the SEM analysis showed that enzymatic hydrolysis coupled with a twin screw extrusion could effectively reduce the diameter and length of cellulose fibers.The produced NFC consisted of microand nanosized fibers entangled in a characteristic 3D-network.Based on the FT-IR analysis,no new bonds were formed during the enzymatic hydrolysis or fibrillation process.The TGA analysis confirmed that produced NFC can be used in hightemperature extrusion processing without NFC degradation.During the PLA/NFC composites preparation the NFC agglomerates were formed,which negatively influenced PLA/NFC composites impact properties.The slightly improved tensile strength and elastic modulus were reported for all composites when compared to the neat PLA.The elongation at break was not affected by the NFC addition.No significant differences in thermal stability were detectable among composites nor in comparation with the neat PLA.However,the crystallinity degree of the composite containing 5 wt%NFC was increased in respect to the neat PLA.展开更多
For advanced conductive hydrogels,adaptable mechanical properties and high conductivity are essential requirements for practical application,e.g.,soft electronic devices.Here,a straightforward strategy to develop a me...For advanced conductive hydrogels,adaptable mechanical properties and high conductivity are essential requirements for practical application,e.g.,soft electronic devices.Here,a straightforward strategy to develop a mechanically robust hydrogel with high conductivity by constructing complicated 3D structures composed of covalently cross-linked polymer network and two nanofillers with distinguishing dimensions is reported.The combination of one-dimensional quaternized cellulose nanofibrils(QACNF)and two-dimensional MXene nanosheets not only provides prominent and tunable mechanical properties modulated by materials composition,but results in electronically conductive path with high conductivity(1281 mS m^(-1)).Owing to the uniform interconnectivity of network structure attributed to the strong macro-molecular interaction and nano-reinforced effect,the resultant hydrogel exhibits a balanced mechanical feature,i.e.,high tensile strength(449 kPa),remarkable stretchability(>1700%),and ultra-high toughness(5.46 MJ m^(-3)),outperforming those of virgin one.Additionally,the enhanced conductive characteristic with the aid of QACNF enables hydrogels with impressive electromechanical behavior,containing high sensitivity(maximum gauge factor:2.24),wide working range(0-1465%),and fast response performance(response time:141 ms,recover time:140 ms).Benefiting from the excellent mechanical performance,a flexible strain sensor based on such conductive hydrogel can deliver an appealing sensing performance of monitoring multi-scale deformations,from large and monotonous mechanical deformation to tiny and complex physiological motions(e.g.,joint movement and signature/vocal recognition).Together,the hydrogel material in this work opens up opportunities in the design and fabrication of advanced gel-based materials for emerging wearable electronics.展开更多
Cellulose nanofibrils(CNFs)are promising sustainable materials that can be applied to nanocomposites,as well as medical and life-sciences devices.However,methods for the preparation of these important materials are en...Cellulose nanofibrils(CNFs)are promising sustainable materials that can be applied to nanocomposites,as well as medical and life-sciences devices.However,methods for the preparation of these important materials are energy intensive because heating and mechanical disintegration are required to produce cellulose fibers below 100 nm in size.In this study,CNFs were prepared through the multi-site regioselective oxidation of cellulose with 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)and periodate at room temperature(20–25°C),without any mechanical-disintegration treatment.Transmission electron microscopy(TEM)revealed that the CNFs had the average widths of 14.1,55.4,and 81.9 nm for three different treatments.Fourier-transform infrared spectroscopy revealed that carboxyl groups were created on the surfaces of the microfibrils,while X-ray diffraction studies showed that the cellulose I structure was maintained after oxidation,and that the cellulose nanofibril crystallinity index exceeded 70%.These results demonstrate that CNFs can be prepared by multi-site regioselective oxidation at room temperature in the absence of mechanical disintegration.In addition,a model was developed to calculate the total content of carboxylate and aldehyde groups of CNFs prepared by the TEMPO mediate oxidation,the periodate oxidation,and the multi-site regioselective oxidation methods based on the particle width determined by TEM.The calculated values of the model were in good agreement with the total content(experimental value)of carboxylate and aldehyde groups of CNFs prepared by the TEMPO-mediated oxidation and the multi-site regioselective oxidation methods.However,the model was not valid for CNFs prepared by the periodate oxidation method.展开更多
Cellulose nanofibril(CNF)was used as the anionic component of two dual strengthening systems wherein polyamidopolyamine epichlorohydrin resin(PAE)or cationic starch(CS)was used as the cationic component.Their strength...Cellulose nanofibril(CNF)was used as the anionic component of two dual strengthening systems wherein polyamidopolyamine epichlorohydrin resin(PAE)or cationic starch(CS)was used as the cationic component.Their strengthening effects were investigated for lowbasis-weight(30 g/m2)paper composed of a mixture of fully bleached softwood and hardwood pulp in a 4:1 mass ratio.Using the PAE/CNF or CS/CNF dual system,it was generally easier to achieve higher wet and dry tensile strengths of paper compared to the paper using the single PAE or CS system.For example,the paper using the PAE(0.4%)/CNF(0.3%)dual system exhibited 89%higher wet tensile strength than the paper using the single PAE(0.4%)system,and the paper using CS(1.3%)/CNF(0.3%)dual treatment showed 21%higher dry strength than that using the single CS(1.3%)system.However,the PAE/CNF system only showed small improvement in the dry strength of paper(11%higher than that of paper using the single PAE system),so did the CS/NFC system on wet strength improvement(only 17%higher than that of paper using the single CS system).展开更多
In this study,carboxymethylation,which introduces carboxyl groups to hydroxyl sites in pulp fibers,was used as a pretreatment before mechanical nanofibrillation.The carboxyl group content of the pulp fibers was greatl...In this study,carboxymethylation,which introduces carboxyl groups to hydroxyl sites in pulp fibers,was used as a pretreatment before mechanical nanofibrillation.The carboxyl group content of the pulp fibers was greatly affected by the dosage of chloroacetic acid and the reaction temperature.During the following fibrillation process,it was found that pulp fibers with higher carboxyl group content exhibited higher water holding capacities and smaller dimensions.A more homogenous structure with a higher amount of individual fibrils was also observed in FE-SEM images of pulp fibers with high carboxyl group content.This can be explained by a high ionic group content in the fiber wall resulting in lower delamination resistance,making the fibrils easier to separate.Carboxymethylation pretreatment as a facilitator of fibrillation in cellulosic pulps is an efficient way to obtain cellulose nanofibrils and consequently decrease the energy consumption of the process.展开更多
The poor salt tolerance,thermal stability,and environmental performance of petrochemicals can severely limit their applications in drilling engineering.In this study,cellulose nanofibril(CNF)hydrogels with improved sa...The poor salt tolerance,thermal stability,and environmental performance of petrochemicals can severely limit their applications in drilling engineering.In this study,cellulose nanofibril(CNF)hydrogels with improved salt tolerance and thermal stability were prepared,and their filtration performance was evaluated.The hydrogels were prepared through the simultaneous grafting of 2-acrylamido-2-methylpropane sulfonic acid(AMPS)and butyl acrylate(BA)onto the CNF surface through ceric ammoniumnitrate-induced radical polymerization.The modified and original CNF samples were characterized using Fourier Transform infrared spectroscopy(FT-IR)and rheological measurements.The FT-IR analysis results showed that both AMPS and BA were grafted onto the CNF backbone,affirming the successful preparation of the grafted CNFs.The rheological analysis results showed that the modified CNF hydrogels exhibited significantly improved salt tolerance,thermal stability,and“salt-thickening”effect.Moreover,the results of the fluid loss test showed that the modified CNF hydrogels exhibited a much better fluid loss control than the original CNF hydrogels.In addition,after adding 2%modified CNF hydrogels as a filtrate reducer in the drilling fluids prepared with a 6%combined salt solution,the filtrate loss was significantly reduced even after aging for 72 h at 160℃.展开更多
Cellulose nanofibrils(CNFs)were obtained through one-step mechano-partial dissolution by ball milling in N,N-dimethyl acetamide with a low concentration of LiCl from agricultural waste bagasse pith(BP).Compared with f...Cellulose nanofibrils(CNFs)were obtained through one-step mechano-partial dissolution by ball milling in N,N-dimethyl acetamide with a low concentration of LiCl from agricultural waste bagasse pith(BP).Compared with fibrous cellulose,parenchyma cellulose(PC)is less uniform in diameter and less aligned,causing PC to dissociate into CNFs during this process without pretreatment.The results showed that the CNFs prepared from PC of BP had a diameter of 30-200 nm and a length of several micrometers.The as-obtained CNFs,along with dissolved cellulose,formed a wet-stable and highly transparent nanopaper in a sorbitol aqueous solution bath,which exhibited a high strain of 101%and a low Young's modulus of 4.3 MPa owing to the addition of the plasticizer sorbitol.This type of nanopaper with favorable transparency,high tensile property,and low Young's modulus has great potential for use as electronic skin and medical dressing material.展开更多
Nanoparticles in air are of particular concern for public health and employee exposure in work-places. Therefore, it is very important to prepare effective filters for their removal. In this work filters were prepared...Nanoparticles in air are of particular concern for public health and employee exposure in work-places. Therefore, it is very important to prepare effective filters for their removal. In this work filters were prepared from nanocellulose, i.e. cellulose nanofibrils (CNF). CNF was produced using two methods giving two different qualities of CNF. One quality had negative charges on the fibril surfaces while the other was neutral, and had in addition thinner fibrils compared to the other qualities. Filter samples were produced from water dispersions of CNF, by removal of the water by freeze drying. The performance of the CNF based filters was assessed and compared with filters based on synthetic polymer fibres. The ability to collect NaCl particles with a broad size distribution, ranging from nanometer to micrometer scale, was determined. CNF filters showed quality values comparable with the synthetic polymer based filters. Filters based on both the two CNF qualities had very good filtration efficiency for a given pressure drop across the filter.展开更多
基金supported by Hibah Penelitian Fundamental Reguler Kementerian Pendidikan,Kebudayaan,Riset dan Teknologi under funding year of 2024 with contract number:051/E5/PG.02.00.PL/2024NKB-903/UN2.RST/HKP.05.00/2024.
文摘Food packaging is becoming popular as the consumption of ready-to-eat food products rises.Easyto-use,non-biodegradable plastic packaging is commonly used in food packaging,contributing to the deteriorating environmental situation.This issue increases the concern for the environment and encourages the usage of alternative materials.Cellulose nanofibrils(CNF)are abundant and biodegradable,which makes them ideal candidates to replace plastic coatings.The ability to form H-bonds between the hydroxyl groups makes coated paper with CNF have good strength,but poor barrier properties.The barrier properties can be improved by grafting DMAEMA or HEMA onto CNF(CNF-g-PDMAEMA and CNF-g-PHEMA,respectively).Thus,the objective of this study was to modify CNF chemically to enhance the barrier properties of the food packaging paper.It was found that paper coated with CNFg-PDMAEMA and CNF-g-PHEMA exhibited improvements in mechanical and barrier properties while maintaining the desired viscosity for the coating process.The water contact angle increased for paper coated with CNF-g-PHEMA and CNF-g-PDMAEMA,reaching a maximum of 97.51°and 92.58°,respectively with the decreasing Cobb_(60) values by 49% and 11%.The oil absorption was also reduced for both coated papers compared to the blank paper.Mechanical properties improved,as indicated by a 3% increase in tensile strength for paper coated with CNF-g-PHEMA and a 5% for paper coated with CNF-g-PDMAEMA.The results indicated significant potential for the application of modified CNF in coatings for food packaging paper.Noteworthy,the grafting process should be improved to enhance the mechanical and barrier properties of the coated paper.
基金financial support from the National Natural Science Foundation of China(31771081,51472259)the Science and Technology Commission of Shanghai Municipality(18ZR1445100)Beijing Forestry University Outstanding Young Talent Cultivation Project(2019JQ03014).
文摘As the rapid development of portable and wearable devices,different electromagnetic interference(EMI)shielding materials with high efficiency have been desired to eliminate the resulting radiation pollution.However,limited EMI shielding materials are successfully used in practical applications,due to the heavy thickness and absence of sufficient strength or flexibility.Herein,an ultrathin and flexible carbon nanotubes/MXene/cellulose nanofibrils composite paper with gradient and sandwich structure is constructed for EMI shielding application via a facile alternating vacuum-assisted filtration process.The composite paper exhibits outstanding mechanical properties with a tensile strength of 97.9±5.0 MPa and a fracture strain of 4.6±0.2%.Particularly,the paper shows a high electrical conductivity of 2506.6 S m?1 and EMI shielding effectiveness(EMI SE)of 38.4 dB due to the sandwich structure in improving EMI SE,and the gradient structure on regulating the contributions from reflection and absorption.This strategy is of great significance in fabricating ultrathin and flexible composite paper for highly efficient EMI shielding performance and in broadening the practical applications of MXene-based composite materials.
基金Funded by the Outstanding Young Scientific Research Personnel Training Plan in Colleges and Universities of Fujian Province(No.GY-Z160146)the Research Fund of Fujian University of Technology(Nos.GY-Z15091,GY-Z160121)+2 种基金the External Cooperative Projects of Fujian Province(No.2018I0001)the Young Teachers Education Research Project(No.JAT170377)Fujian Province Undergraduate Training Program for Innovation and Entrepreneurship(No.201810388048)
文摘Composite nanofiber membranes based on biodegradable poly(lactic acid)(PLA) and cellulose nanofibrils(CNF) were produced via electrospinning. The influence of CNF content on the morphology, thermal properties, and mechanical properties of PLA/CNF composite nanofiber membranes were characterized by field scanning electron microscopy(FE-SEM), differential scanning calorimetry(DSC), thermogravimetric analysis(TGA), and dynamic mechanical analysis(DMA), respectively. The results show that the PLA/CNF composite nanofibers with smooth, free-bead surface can be successfully fabricated with various CNF contents. The introduction of CNF is an effective approach to improve the crystalline ability, thermal stability and mechanical properties for PLA/CNF composite fibers. The Young's moduli and tensile strength of the PLA/CNF composite nanofiber reach 106.6 MPa and 2.7 MPa when the CNF content is 3%, respectively, which are one times higher and 1.5 times than those of pure PLA nanofiber. Additionally, the water contact angle of PLA/CNF composite nanofiber membranes decreases with the increase of the CNF loading, resulting in the enhancement of their hydrophilicity.
基金financially sponsored by the Science and Technology Commission of Shanghai Municipality(nos.20230742300 and 18595800700)。
文摘The design of flexible polymeric films with internal porous structures has received increasing attention in low dielectric applications.The highly porous metal-organic frameworks(MOFs)of[Cu_(3)(BTC)_(2)]_(n)(BTC=benzene-1,3,5-tricarboxylate)were introduced into aramid nanofibers(ANF)matrix by using carboxylated cellulose nanofibrils(CNF)as carriers to obtain strong,flexible,and ultra-low dielectric films.The well-dispersed“flowers-branch”like CNF@CuBTC through in-situ growth of CuBTC on CNF surface endowed the ANF/CNF@Cu BTC films with excellent thermal stability,mechanical integrity and low dielectric properties.Besides,the flexible dielectric films exhibited superior ultraviolet(UV)resistance,lower coefficient of thermal expansion(4.28×10^(-5)℃^(-1))and increased water contact angle(83.81°).More interestingly,the removal of vip molecules from the ANF/CNF@CuBTC films according to the vacuum heat treatment(VHT)process significantly improved their dielectric response.The specific surface areas of the composite films after VHT increased obviously,and the dielectric constant and dielectric loss tangent decreased to the expected 1.8-2.2 and 0.001-0.03 at 100 MHz,respectively.Consequently,such designable ultra-low dielectric films with high flexibility play an incredible significance in applications of microelectronics under large deformation conditions,especially in flexible/wearable devices at the arrival of 5 G era.
基金supported by the National Natural Science Foundation of China(No 69890220)
文摘TiO2 nanofibrils were prepared within the pores of alumina template membrane by use of sol-gel chemistry. The TiO2 nanofibrils have good crystallinity and size. There is agglomeration free among the particulates of TiO2 and the fibrils show high catalytic activity.
文摘Two-dimensional covalent organic framework nanosheets(CONs)with ultrathin thickness and porous crystalline nature show substantial potential as novel membrane materials.However,bringing CONs materials into flexible membrane form is a monumental challenge due to the limitation of weak interactions among CONs.Herein,one-dimensional silk nanofibrils(SNFs)from silkworm cocoon are designed as the nanobinder to link sulfonated CON(SCON)into robust SCON-based membrane through vacuum-filtration method.Ultrathin and large lateral-sized SCONs are synthesized via bottom-up interface-confined synthesis approach.Benefiting from high length-diameter ratio of SNF and rich functional groups in both SNF and SCON,two-dimensional(2D)SCONs are effectively connected together by physical entanglement and strong H-bond interactions.The resultant SCON/SNF membrane displays dense structure,high mechanical integrity and good stability.Importantly,the rigid porous nanochannels of SCON,high-concentration-SO3H groups insides the pores and H-bonds at SCON-SNF interfaces impart SCON/SNF membrane high-rate proton transfer pathways.Consequently,a superior proton conductivity of 365 mS cm^(-1)is achieved at 80C and 100%RH by SCON/SNF membrane.This work offers a promising approach for connecting 2D CON materials into flexible membrane as high-performance solid electrolyte for hydrogen fuel cell and may be applied in membrane-related other fields.
基金supported by the National Natural Science Foundation of China(No.21876072)the Talent Innovation and Entrepreneurship Project of Lanzhou(No.2018-RC-04)+1 种基金Special Fund Project for the Central Government to Guide Local Science and Technology Development(2020)the 111 Project(No.B20027)。
文摘The disinfection of waterborne pathogens from drinking water is extremely important for human health.Although countless efforts have been devoted for drinking water inactivation,challenges still exist in terms of relative high energy consumption and complicated to implement and maintain.Here,silver nanoparticles anchoring wood carbon(Ag NPs/WC)membrane is developed as cost-effective,high flux,scalable filter for highly efficient electric field disinfection of water.Under electric field of 4 V voltage,the designed membrane achieved more than 5 log(99.999%)disinfection performance for different model bacteria,including Escherichia coli(E.coli),Enterococcus faecalis(E.faecalis),Salmonella enterica serovar Typhimirium(S.Typhimurium)and Bacillus subtilis(B.subtilis)with a high flux of 3.8 x 103 L m^(-2)h^(-1),extremely low energy consumption of 2 J L^(-1)m^(-2)and fantastic durability(7 days).The high disinfection performance of Ag NPs/WC membrane is attributed to the synergistic disinfection of carbon nanofibrils,Ag nanoparticles as well as the low tortuous structure of the channels in wood carbon.The Ag NPs/WC membrane presents a promising strategy for point-of-use drinking water electric field disinfection treatment.
基金grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.31770628 and 31901267)the Taishan Scholars Program+3 种基金the Provincial Key Research and Development Program of Shandong(Grant Nos.2019JZZY010326 and 2019JZZY010328)a projectu(Grant No.ZR2019BC042)supported by the Shandong Provincial Natural Science Foundationa project of the Shandong Province Higher Educational Science and Technology Program(J18KA111).
文摘Recently,cellulose nanofibril(CNF)has emerged as a promising,sustainable reinforcement with outstanding potential in material science.Owing to the properties of CNF,it has been explored in food,cosmetic,and pharmaceutical applications,as well as in industrial applications such as paints,drill muds,packaging,and papermaking.The application of CNF in papermaking is expected to be implemented in the near future to broaden the commercial market of cellulose.Numerous studies and patents have reported on the manufacturing,properties,and applications of nanocellulose.This present paper focuses on the recent progresses in the application of CNF as a wet-end additive in papermaking.
基金supported by the National Natural Science Foundation of China(No.32071347)the ZJU-Hangzhou Global Scientific and Technological Innovation Center,Zhejiang University(No.02020200-K02013008)the Joint Laboratory Grant from Jiangsu Wuzhong Aesthetics Biotech Co.,Ltd.,and the Starting Grant of ShanghaiTech University.
文摘Multicellular spheroids,which mimic the natural organ counterparts,allow the prospect of drug screening and regenerative medicine.However,their application is hampered by low processing efficiency or limited scale.This study introduces an efficient method to drive rapid multicellular spheroid formation by a cellulose nanofibril matrix.This matrix enables the facilitated growth of spheroids(within 48 h)through multiple cell assembly into size-controllable aggregates with well-organized physiological microstructure.The efficiency,dimension,and conformation of the as-formed spheroids depend on the concentration of extracellular nanofibrils,the number of assembled cells,and the heterogeneity of cell types.The above strategy allows the robust formation mechanism of compacted tumoroids and hepatocyte spheroids.
基金financial support for this work is from the National Science&Technology Pillar Program during the Twelfth Five-year Plan Period(No.2015BAD14B06)the National Natural Science Foundation of China(No.31470609,No.25106240 and No.21433001)+1 种基金the Primary Research and Development Plan of Shandong Province(No.2016GGX104003 and No.2016CYJS07A02)the Young Taishan Scholars Program of Shandong Province(No.tsqn20161052)
文摘In this study, cellulose nanocrystals(CNC) with surface carboxylic groups were prepared from bleached softwood pulp by hydrolysis with concentrated citric acid at concentrations of 60 wt%~80 wt%. The solid residues from acid hydrolysis were collected for producing cellulose nanofibrils(CNF) via post high-pressure homogenization. Citric acid could be easily recovered after hydrolysis reactions through crystallization due to its low water solubility or through precipitation as a calcium salt followed by acidification. Several important properties of CNC and CNF, such as dimension, crystallinity, surface chemistry, thermal stability, were evaluated. Results showed that the obtained CNC and CNF surfaces contained carboxylic acid groups that facilitated functionalization and dispersion in aqueous processing. The recyclability of citric acid and the carboxylated CNC/CNF give the renewable cellulose nanomaterial huge potential for a wide range of industrial applications. Furthermore, the resultant CNC and CNF were used as reinforcing agents to make sodium carboxymethyl cellulose(CMC) films. Both CNC and CNF showed reinforcing effects in CMC composite films. The tensile strength of CMC films increased by 54.3% and 85.7% with 10 wt% inclusion of CNC and CNF, respectively. This study provides detailed information on carboxylated nanocellulose prepared by critic acid hydrolysis; a sustainable approach for the preparation of CNC/CNF is of significant importance for their various uses.
文摘To improve the performance of polyurethane films,small amounts of cellulose nanofibrils(CNF)were physically blended with a waterborne polyurethane(WPU)emulsion,and then CNF/WPU composite films were prepared by cast-coating and drying.The particle size of the emulsions and the chemical structure,micromorphology,thermal stability,mechanical properties,and water resistance of the composite films were characterized using a Malvern laser particle size analyzer,Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),thermogravimetric analysis(TGA),an electronic strength machine,water contact angle analysis(WCA),and water absorption tests,respectively.The results showed that at a low CNF content of 0.3 wt%,the particle size of the WPU emulsion and chemical structure of the film did not change significantly.In addition,the tensile strength of the composite film increased by up to 108%compared to the neat WPU film,and the thermal stability and water resistance were slightly improved.The addition of CNF greatly enhanced the tensile strength while maintaining the other original properties of the WPU film,which may greatly improve the service life and tear resistance of commercial coatings in the future.
文摘Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character.Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils,and a resin of poly(styrene-methyl-methacrylate-acrylic acid)used as water-based emulsion.Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions.The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension,leading to the co-precipitation of the composite material,which can be easily separated from the water phase.Composites with acrylic polymer/cellulose fibers in the proportions of 75:25,50:50 and 25:75 wt%were prepared.Composites were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),dynamic mechanical analysis(DMA)and water absorption tests.SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration,which led to superior mechanical properties.These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials.
文摘In the current study poly(lactic acid)PLA composites with a 3 wt%and 5 wt%of nanofibrillated cellulose(NFC)were produced by 3D-printing method.An enzymatic pretreatment coupled with mechanical fibrillation in a twin screw extruder was used to produce high consistency NFC.Scanning electron microscopy(SEM)equipped with Fibermetric software,FASEP fiber length distribution analysis,Furrier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TGA),tensile tests,impact tests and differential scanning calorimetry were used to characterize NFC and PLA/NFC composites.The results of the fiber length and width measurements together with the results of the SEM analysis showed that enzymatic hydrolysis coupled with a twin screw extrusion could effectively reduce the diameter and length of cellulose fibers.The produced NFC consisted of microand nanosized fibers entangled in a characteristic 3D-network.Based on the FT-IR analysis,no new bonds were formed during the enzymatic hydrolysis or fibrillation process.The TGA analysis confirmed that produced NFC can be used in hightemperature extrusion processing without NFC degradation.During the PLA/NFC composites preparation the NFC agglomerates were formed,which negatively influenced PLA/NFC composites impact properties.The slightly improved tensile strength and elastic modulus were reported for all composites when compared to the neat PLA.The elongation at break was not affected by the NFC addition.No significant differences in thermal stability were detectable among composites nor in comparation with the neat PLA.However,the crystallinity degree of the composite containing 5 wt%NFC was increased in respect to the neat PLA.
基金supported by the National Natural Science Foundation of China(Nos.52203148,51973047,and 12002113)the Research Foundation of Talented Scholars of Zhejiang A&F University(Nos.2020FR070 and 2021FR024)+1 种基金the Zhejiang A&F University Scientific Research Training Program for Undergraduates(No.S202210341186)the Key Research and Development Program of Shaanxi(No.2022-JBGS3-09).
文摘For advanced conductive hydrogels,adaptable mechanical properties and high conductivity are essential requirements for practical application,e.g.,soft electronic devices.Here,a straightforward strategy to develop a mechanically robust hydrogel with high conductivity by constructing complicated 3D structures composed of covalently cross-linked polymer network and two nanofillers with distinguishing dimensions is reported.The combination of one-dimensional quaternized cellulose nanofibrils(QACNF)and two-dimensional MXene nanosheets not only provides prominent and tunable mechanical properties modulated by materials composition,but results in electronically conductive path with high conductivity(1281 mS m^(-1)).Owing to the uniform interconnectivity of network structure attributed to the strong macro-molecular interaction and nano-reinforced effect,the resultant hydrogel exhibits a balanced mechanical feature,i.e.,high tensile strength(449 kPa),remarkable stretchability(>1700%),and ultra-high toughness(5.46 MJ m^(-3)),outperforming those of virgin one.Additionally,the enhanced conductive characteristic with the aid of QACNF enables hydrogels with impressive electromechanical behavior,containing high sensitivity(maximum gauge factor:2.24),wide working range(0-1465%),and fast response performance(response time:141 ms,recover time:140 ms).Benefiting from the excellent mechanical performance,a flexible strain sensor based on such conductive hydrogel can deliver an appealing sensing performance of monitoring multi-scale deformations,from large and monotonous mechanical deformation to tiny and complex physiological motions(e.g.,joint movement and signature/vocal recognition).Together,the hydrogel material in this work opens up opportunities in the design and fabrication of advanced gel-based materials for emerging wearable electronics.
基金This research was funded by The Talents Project for Harbin Science and Technology Innovation,grant number 2016RAXXJ006China Postdoctoral Science Foundation,grant number 2017M611341.
文摘Cellulose nanofibrils(CNFs)are promising sustainable materials that can be applied to nanocomposites,as well as medical and life-sciences devices.However,methods for the preparation of these important materials are energy intensive because heating and mechanical disintegration are required to produce cellulose fibers below 100 nm in size.In this study,CNFs were prepared through the multi-site regioselective oxidation of cellulose with 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)and periodate at room temperature(20–25°C),without any mechanical-disintegration treatment.Transmission electron microscopy(TEM)revealed that the CNFs had the average widths of 14.1,55.4,and 81.9 nm for three different treatments.Fourier-transform infrared spectroscopy revealed that carboxyl groups were created on the surfaces of the microfibrils,while X-ray diffraction studies showed that the cellulose I structure was maintained after oxidation,and that the cellulose nanofibril crystallinity index exceeded 70%.These results demonstrate that CNFs can be prepared by multi-site regioselective oxidation at room temperature in the absence of mechanical disintegration.In addition,a model was developed to calculate the total content of carboxylate and aldehyde groups of CNFs prepared by the TEMPO mediate oxidation,the periodate oxidation,and the multi-site regioselective oxidation methods based on the particle width determined by TEM.The calculated values of the model were in good agreement with the total content(experimental value)of carboxylate and aldehyde groups of CNFs prepared by the TEMPO-mediated oxidation and the multi-site regioselective oxidation methods.However,the model was not valid for CNFs prepared by the periodate oxidation method.
基金supported by the National Program on Key Research & Development Project of China (Grant No. 2017YFB0307902)
文摘Cellulose nanofibril(CNF)was used as the anionic component of two dual strengthening systems wherein polyamidopolyamine epichlorohydrin resin(PAE)or cationic starch(CS)was used as the cationic component.Their strengthening effects were investigated for lowbasis-weight(30 g/m2)paper composed of a mixture of fully bleached softwood and hardwood pulp in a 4:1 mass ratio.Using the PAE/CNF or CS/CNF dual system,it was generally easier to achieve higher wet and dry tensile strengths of paper compared to the paper using the single PAE or CS system.For example,the paper using the PAE(0.4%)/CNF(0.3%)dual system exhibited 89%higher wet tensile strength than the paper using the single PAE(0.4%)system,and the paper using CS(1.3%)/CNF(0.3%)dual treatment showed 21%higher dry strength than that using the single CS(1.3%)system.However,the PAE/CNF system only showed small improvement in the dry strength of paper(11%higher than that of paper using the single PAE system),so did the CS/NFC system on wet strength improvement(only 17%higher than that of paper using the single CS system).
基金financial support from the National Key Research and Development Program of China (Grant No.2017YFB0307900)the National Natural Science Foundation of China (Grant No.31470602,31670595,31770628)the Taishan Scholars Program
文摘In this study,carboxymethylation,which introduces carboxyl groups to hydroxyl sites in pulp fibers,was used as a pretreatment before mechanical nanofibrillation.The carboxyl group content of the pulp fibers was greatly affected by the dosage of chloroacetic acid and the reaction temperature.During the following fibrillation process,it was found that pulp fibers with higher carboxyl group content exhibited higher water holding capacities and smaller dimensions.A more homogenous structure with a higher amount of individual fibrils was also observed in FE-SEM images of pulp fibers with high carboxyl group content.This can be explained by a high ionic group content in the fiber wall resulting in lower delamination resistance,making the fibrils easier to separate.Carboxymethylation pretreatment as a facilitator of fibrillation in cellulosic pulps is an efficient way to obtain cellulose nanofibrils and consequently decrease the energy consumption of the process.
基金the National Natural Science Foundation of China(Grant No.31700514)the Natural Science Foundation of Tianjin,China(Grant No.18JCYBJC86500)for their financial supports
文摘The poor salt tolerance,thermal stability,and environmental performance of petrochemicals can severely limit their applications in drilling engineering.In this study,cellulose nanofibril(CNF)hydrogels with improved salt tolerance and thermal stability were prepared,and their filtration performance was evaluated.The hydrogels were prepared through the simultaneous grafting of 2-acrylamido-2-methylpropane sulfonic acid(AMPS)and butyl acrylate(BA)onto the CNF surface through ceric ammoniumnitrate-induced radical polymerization.The modified and original CNF samples were characterized using Fourier Transform infrared spectroscopy(FT-IR)and rheological measurements.The FT-IR analysis results showed that both AMPS and BA were grafted onto the CNF backbone,affirming the successful preparation of the grafted CNFs.The rheological analysis results showed that the modified CNF hydrogels exhibited significantly improved salt tolerance,thermal stability,and“salt-thickening”effect.Moreover,the results of the fluid loss test showed that the modified CNF hydrogels exhibited a much better fluid loss control than the original CNF hydrogels.In addition,after adding 2%modified CNF hydrogels as a filtrate reducer in the drilling fluids prepared with a 6%combined salt solution,the filtrate loss was significantly reduced even after aging for 72 h at 160℃.
基金The authors are grateful for the financial support from the National Natural Science Foundation of China(Grant No.51963012)Special Foundation for Excellent Youth Scholars of Yunnan Province,China(Nos.YNWR-QNBJ-2020-039 and YNWR-QNBJ-2020-045).
文摘Cellulose nanofibrils(CNFs)were obtained through one-step mechano-partial dissolution by ball milling in N,N-dimethyl acetamide with a low concentration of LiCl from agricultural waste bagasse pith(BP).Compared with fibrous cellulose,parenchyma cellulose(PC)is less uniform in diameter and less aligned,causing PC to dissociate into CNFs during this process without pretreatment.The results showed that the CNFs prepared from PC of BP had a diameter of 30-200 nm and a length of several micrometers.The as-obtained CNFs,along with dissolved cellulose,formed a wet-stable and highly transparent nanopaper in a sorbitol aqueous solution bath,which exhibited a high strain of 101%and a low Young's modulus of 4.3 MPa owing to the addition of the plasticizer sorbitol.This type of nanopaper with favorable transparency,high tensile property,and low Young's modulus has great potential for use as electronic skin and medical dressing material.
文摘Nanoparticles in air are of particular concern for public health and employee exposure in work-places. Therefore, it is very important to prepare effective filters for their removal. In this work filters were prepared from nanocellulose, i.e. cellulose nanofibrils (CNF). CNF was produced using two methods giving two different qualities of CNF. One quality had negative charges on the fibril surfaces while the other was neutral, and had in addition thinner fibrils compared to the other qualities. Filter samples were produced from water dispersions of CNF, by removal of the water by freeze drying. The performance of the CNF based filters was assessed and compared with filters based on synthetic polymer fibres. The ability to collect NaCl particles with a broad size distribution, ranging from nanometer to micrometer scale, was determined. CNF filters showed quality values comparable with the synthetic polymer based filters. Filters based on both the two CNF qualities had very good filtration efficiency for a given pressure drop across the filter.
