Incorporation Of Cellulose Nanofibers Research Articles

Olive pomace upcycling: Eco-friendly production of cellulose nanofibers by enzymatic hydrolysis and application in starch films.

Olive pomace (OP) waste, produced in large quantities, contains significant amounts of cellulose and fibers, making it a valuable resource for developing reinforcing ingredients in biodegradable packaging materials. This study aimed to produce nanofibers from OP using enzymatic hydrolysis with hemicellulases and cellulases, and to incorporate these nanofibers into starch films as a reinforcing agent. Cellulose nanofibers (CNFs) were prepared by alkaline pretreatment followed by enzymatic hydrolysis (with hemicellulases and cellulases) from olive pomace and applied as reinforcement in starch films in concentrations of 0.5%-5% (w/v). The nanofibers were analyzed according to composition, structural, and thermal properties. The nanofibers' suspension presented a cloudy and white color in aqueous suspension, the X-ray diffraction (XRD) analysis showed the increase of crystallinity, and the fibers' range was no wider than 100nm (according to Scherer equation). The composition analysis showed the decrease of carbonyl groups of hemicellulose and lignin. The starch films presented a homogenous surface. The solubility from these biodegradable films significantly reduced after the incorporation of CNF, and the nanomaterial's presence improved the degradation temperature (from 310°C to 322°C) and the mechanical resistance because the tension of rupture increased from 3.79 to 6.21MPa. PRACTICAL APPLICATION: The utilization of waste from the olive pomace for cellulose nanofiber production holds promise, given the nanofibers' ability to readily integrate into various materials, including starches used in biodegradable film production. Within these matrices, nanofibers act as structure reinforcers and significantly reduce the solubility of films. Although biodegradable films ensure the shelf life, safety, and quality of food, their properties currently do not match those of traditional petroleum-based materials at an industrial scale, indicating a need for further enhancement.

Biodegradable gelatin/pectin films containing cellulose nanofibers and biguanide polymers: Characterization and application in sweet cherry packaging

To expand the utilization of gelatin and pectin derived from agricultural by-products, the composite films composed of gelatin, citrus pectin, cellulose nanofibers (CNF), and polyhexamethylene biguanide hydrochloride (PHMB) were prepared through the solvent casting method. Fourier infrared spectroscopy analysis verified the successful integration of CNF and PHMB into the gelatin-pectin matrix. The incorporation of CNF as a reinforcing agent substantially enhanced the barrier capabilities of the composite film. Moreover, the addition of PHMB, functioning as an antimicrobial agent, not only granted the film with antibacterial properties but also improved its physical characteristics and biodegradability. A water contact angle experiment revealed the film presented a certain degree of hydrophobicity. The optimal performances were attained with a composition in which CNF and PHMB constituted 8 % and 3 %, respectively, of the total weight of gelatin and pectin. As a packaging film, the composite film demonstrated its effectiveness by reducing the decay index and weight loss rate of sweet cherries during a 12-day storage period. In the soil degradation test, the composite film exhibited notable structural degradation by the 16th day. Consequently, the composite film will be used as an innovative and biodegradable packaging material to provide a sustainable solution for food packaging industries.

Construction of a sustainable and hydrophobic high-performance all-green pineapple peel cellulose nanocomposite film for food packaging

The increasing global awareness of environmental issues has led to a growing interest in research on cellulose-based film. However, several limitations hinder their development and industrial application, such as hydrophilicity, inadequate mechanical properties and barrier properties, and a lack of activity. This study aimed to create a sustainable and hydrophobic high-performance all-green pineapple peel cellulose nanocomposite film for food packaging by incorporating natural carnauba wax and cellulose nanofibers (CNF) into a pineapple peel cellulose matrix. The results showed that adding carnauba wax to the cellulose matrix converted the surface wettability of the cellulose-based film from hydrophilic to hydrophobic (water contact angle over 100). Additionally, the film exhibited ultraviolet resistance and antioxidation properties. The incorporation of CNF further improved the barrier properties, mechanical properties, and thermal stability of the cellulose nanocomposite film. In applied experiments, the cellulose nanocomposite film delayed post-harvest deterioration and maintained storage quality of cherry tomatoes. Importantly, the cellulose nanocomposite film could be degraded in soil within 30 days. It can be concluded that the cellulose nanocomposite film has great potential to alleviate the environmental problems and human health problems caused by non-degradable petroleum-based plastic packaging.

Fungicidal Potential of Polymeric Hydrogels Based on Carboxymethylcellulose and Yerba Mate Residues with the Incorporation of Garlic Oil

AbstractIn the present study, hydrogels are developed from carboxymethylcellulose, with the addition of cellulose nanofibers (CNFs) obtained from yerba mate stick residues and garlic oil. CNFs are obtained via physical (steam explosion), chemical (bleaching), and mechanical (ultrafine friction milling) processes. Garlic oil is encapsulated into sodium alginate for the evaluation of fungicidal potential. The samples are assessed for characteristics such as water absorption capacity (swelling) and inhibitory activity against Fusarium sp. FUS147 in vitro by Fourier‐transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). TGA and FTIR spectra confirm the cross‐linking mechanism for citric acid in sodium carboxymethylcellulose (CMC) in the hydrogel formation. The incorporation of CNFs, sodium alginate, and garlic oil reduces the temperature at the beginning of thermal degradation, to 47, 38, and 31 °C, respectively, in relation to a hydrogel sample with only carboxymethylcellulose (HC). The swelling analysis reveals an increase of 57% for a sample with CNF, and 42% for a sample with incorporation of garlic oil encapsulated in alginate, in relation to the HC sample. The sample with encapsulated garlic oil shows a high degree of swelling with broad antifungal activity against the Fusarium sp. FUS147, showing great potential for use in agriculture.

Preparation of high-strength dynamic polysaccharide nanocomposite hydrogels and their application towards dye adsorption

The preparation and application of natural dynamic polysaccharide hydrogels have been attractive in recent years. Herein, carboxymethyl chitosan (CMCht) and oxidized acetoacetate cellulose (OCAA) were used to prepare polysaccharide nanocomposite hydrogel for dye adsorbent by one pot method mixing glutaraldehyde (GA) and cellulose nanofibers (CNFs), and mechanical, rheological, self-healing and dye adsorption properties were investigated. Consequently, compared with CMCht/OCAA hydrogel, the addition of GA crosslinker together with 1 % CNF increased strengths by ∼520 %, tensile strengths from 259 KPa to 1.35 MPa and compressive strength from 450 KPa to 2.35 MPa, respectively. The nanocomposite hydrogels demonstrated excellent anti-fatigue performance, and its experimental modulus result was fit Halpin-Kardos and Ouali model. Moreover, the freeze-dried gels showed a good removal effect for methylene blue dye from water, and its adsorption capacity and removal efficiency could reach up to 564.64 mg/g and 94 % due to the presence of dynamic covalent and hydrogen bonds in the composite hydrogel. This work developed a high-strength dynamic polysaccharide hydrogels incorporation of CNFs, which shows promising applications in environmental fields especially water pollution adsorption treatment.

Power Output Enhancement of Natural Rubber Based Triboelectric Nanogenerator with Cellulose Nanofibers and Activated Carbon.

The growing demand for energy and environmental concern are crucial driving forces for the development of green and sustainable energy. The triboelectric nanogenerator (TENG) has emerged as a promising solution for harvesting mechanical energy from the environment. In this research, a natural rubber (NR)-based TENG has been developed with an enhanced power output from the incorporation of cellulose nanofibers (CNF) and activated carbon (AC) nanoparticles. The highest voltage output of 137 V, a current of 12.1 µA, and power density of 2.74 W/m2 were achieved from the fabricated NR-CNF-AC TENG. This is attributed to the synergistic effect of the electron-donating properties of cellulose material and the large specific surface area of AC materials. The enhancement of TENG performance paves the way for the application of natural-based materials to convert mechanical energy into electricity, as a clean and sustainable energy source.

Nanocomposites of low-density polyethylene and nanocellulose: An alternative route using bleached cellulose nanofibers gel suspension

The production of thermoplastic composites with nanocellulose has proven a great challenge due the tendency to form strong nanocellulose agglomerates during dispersion or when they are dried. In this research, an alternative method for preparing composites based on bleached cellulose nanofibers (CNF) gel suspension and low-density polyethylene (LDPE) using thermokinetic mixing (Drais mixer) is described. This process makes it possible to use cellulose nanofibers in gel suspension (pulp), without the need for prior drying. For that, a masterbatch was first prepared by mixing the CNF in gel suspension (95%wt moisture) with LDPE in a Drais type homogenizer. The masterbatch was then grinded and incorporated into the LDPE matrix at various contents using a co-rotating twin-screw extruder. The produced materials were characterized using thermal, mechanical and dynamic-mechanical techniques. Efficient incorporation of CNF into LDPE was obtained, that is, no traces of moisture or thermal and/or hydrolytic degradation were noticed, and similar mechanical and dynamic-mechanical properties compared to the neat polymer was obtained. The proposed method was found to have a relevant technological aspect with potential application in the cellulose/polymer industry, aiming to overcome the difficulty of working in water media.

Isolation and Characterization of Cellulose Nanofibers from Wheat Straw and Their Application for the Supercapacitor

As a by-product of wheat planting, wheat straw is an abundant agricultural residue with the highest cellulose content of all agricultural fibers. Its resourceful utilization contributes to alleviating the environmental problems it caused. In this study, cellulose from wheat straw (WS) is used as a dispersing agent to prepare a novel multi-walled carbon nanotube-modified nickel foam (NF) electrode. The new electrode is investigated for electrochemical properties relevant to supercapacitors. The 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation is chosen to produce cellulose nanofibers (CNF) from wheat straw. The prepared CNF is used to facilitate the uniform dispersion of multi-walled carbon nanotubes (MWCNT) and favor the formation of a stable CNF-CNTs membrane on the nickel foam skeleton. The influence of dispersing materials and content of CNF on the electrochemical performance of electrodes is investigated. It is revealed that the incorporation of CNF can improve the electrochemical stability of electrodes. Moreover, it also exhibits optimum capabilities (70.2% capacitance retention from 1 to 40 mA cm−2) when CNF:MWCNT = 1:0.7. The areal capacity of the CNF-MWCNT/NF electrode for a scanning rate of 5 mV s−1 is twice that of the MWCNT/NF electrode and 30 times that of the NF electrode, indicating it is a promising candidate to ensure the synchronization of a green environment and energy development.

SYNTHESIS OF CELLULOSE-BASED SUPERABSORBENT HYDROGEL FILLED WITH CELLULOSE NANOFIBER FROM OIL PALM EMPTY FRUIT BUNCHES

Oil palm empty fruit bunches (OPEFB) are waste products from the oil palm plantations, which is still an issue in Indonesian plantations. The high cellulose content in OPEFB enables them to be processed into cellulose nanofibers (CNF) that can be applied as fillers in the hydrogel. This research aimed to synthesize cellulose-based superabsorbent hydrogel and observe the optimal condition to produce hydrogel with high absorption and good thermal properties. CNF-based hydrogel is an excellent option to improve the physicochemical characteristics of the hydrogel. In this work, carboxy methyl cellulose hydrogel was firstly prepared by using citric acid. Then, CNF were added as fillers at different ratio variations, such as 0, 1, 3, 5, and 7 wt%. The surface morphology of the hydrogel showed rough surfaces, except for the 7 wt% CNF variation that produced hydrogel with a homogeneous surface. The cross-linking between the hydrogel and the fillers was evaluated by Fourier-Transform Infrared Spectroscopy (FTIR). A peak associated with the carboxylic acid functional group indicated hydrogel formation. The incorporation of CNF did not change the FTIR spectra since both materials had similar structures. Water absorption analysis showed that the developed product could be classified as a superabsorbent since all samples showed a degree of swelling above 200 g.g−1. CNF content at a 1 %wt ratio had the highest water retention and best thermal stability. The hydrogel showed exceptional characteristics, being suitable for various applications, mainly in agricultural sectors that required water delivery to the soil.

Antifungal features and properties of chitosan/sandalwood oil Pickering emulsion coating stabilized by appropriate cellulose nanofiber dosage for fresh fruit application

A novel composite edible coating film was developed from 0.8% chitosan (CS) and 0.5% sandalwood oil (SEO). Cellulose nanofibers (CNFs) were used as a stabilizer agent of oil-in-water Pickering emulsion. We found four typical groups of CNF level-dependent emulsion stabilization, including (1) unstable emulsion in the absence of CNFs; (2) unstable emulsion (0.006–0.21% CNFs); (3) stable emulsion (0.24–0.31% CNFs); and (4) regular emulsion with the addition of surfactant. Confocal laser scanning microscopy was performed to reveal the characteristics of droplet diameter and morphology. Antifungal tests against Botrytis cinerea and Penicillium digitatum, between emulsion coating stabilized with CNFs (CS-SEOpick) and CS or CS-SEO was tested. The effective concentration of CNFs (0.24%) may improve the performance of CS coating and maintain CS-SEO antifungal activity synergistically confirmed with a series of assays (in vitro, in vivo, and membrane integrity changes). The incorporation of CNFs contributed to improve the functional properties of CS and SEO-loaded CS including light transmission at UV and visible light wavelengths and tensile strength. Atomic force microscopy and scanning electron microscopy were employed to characterize the biocompatibility of each coating film formulation. Emulsion-CNF stabilized coating may have potential applications for active coating for fresh fruit commodities.

Enhancing the Mechanical Performance of Reduced Graphene Oxide Aerogel with Cellulose Nanofibers

AbstractUltralight, highly compressible and superelastic carbon materials hold great promise in wearable and flexible electronic devices, but the fabrication remains to be a challenge because of the brittleness nature of carbon. Herein, a carbon aerogel with ultralow density yet high mechanical performance is successfully fabricated from graphene oxide (GO) liquid crystal stabilized bubbles with the enhancement of cellulose nanofiber (CNF). The incorporation of CNF into reduced graphene oxide (rGO) nanosheets enhances the interaction among rGO nanosheets through welding effect, which restricts the slip of rGO nanosheets and the detachment among microspheres, leading to a significant improvement on mechanical properties. The as‐prepared carbon aerogel with tightly packaged cell‐wall architecture displays ultrahigh compressibility (up to 99% strain) and elasticity (90.1% stress retention and 99.0% height retention after 10000 cycles at 50% strain), which are superior to those of the present bubble‐templated carbon aerogels and many other carbon materials through various methods. The structural feature leads to rapid and stable current response and high sensitivity to external strain and pressure, allowing the carbon aerogel to detect very small pressure and various human motions from finger bending to pulse. These advantages make the carbon aerogel promising for flexible electronic devices.

Effect of laboratory-produced cellulose nanofiber as an additive on performance of asphalt binders and mixes

In recent years, major initiatives have been taken to replace non-renewable materials with environmentally friendly and sustainable ones. The present study was undertaken to apply a scalable process for laboratory production of Cellulose Nanofibers (CNF) and to evaluate feasibility of using the produced CNF as a sustainable plant-based asphalt additive to improve the mechanical properties and durability of asphalt pavements. To achieve this goal, CNF was produced in the laboratory by applying electrospinning technique. Structure, morphology, and the size distribution of the produced CNF were evaluated using Scan Electron Microscopy. Also, tensile strength tests in two perpendicular directions were conducted on lab-produced CNF. The effect of incorporating different amounts of CNF in three types of asphalt binders, namely PG 58-28, PG 64-34, and PG 70-28 on fracture energy and dynamic viscosity of binder blends were evaluated by conducting Izod impact and rotational viscometer tests, respectively. Additionally, effect of CNF dosage in binder on its adhesion and moisture-induced debonding potential with aggregates of three different mineralogy was evaluated by conducting binder bond strength test. Furthermore, effect of incorporating CNF in asphalt mixes on their cracking, rutting, and moisture-induced damage potential was evaluated by conducting semicircular bend, Hamburg wheel tracking, and tensile strength ratio tests, respectively. From the tests conducted on asphalt binders and mixes, it was concluded that, incorporation of CNF resulted in an overall improvement in binder-aggregates adhesion, an asphalt binder with a higher fracture energy and dynamic viscosity, and an asphalt mix with a higher resistance to rutting, cracking, and moisture-induced damage.

Lightweight investigation of long chain branching polypropylene/cellulose nanofiber composite foams

AbstractLong chain branching polypropylene (LCBPP)/cellulose nanofiber (CNF) composite foams were prepared by short shot foam injection molding method and their morphological, mechanical, and thermal properties were also investigated. The cellular structure of LCBPP/CNF composite foams was improved with weight reduction (WR) ratios increasing. The cell densities of LCBPP/CNF composite foams were dramatically increasing with WR ratios rising. More, the fine and uniform cellular structures were obtained due to the incorporation of CNF. The highest cell density, specific flexural strength, and modulus could achieved 20 × 103 cell/cm2, 65 MPa/(g/cm3) and 2.7 GPa/(g/cm3), respectively. Furthermore, the specific Charpy impact strengths were also higher than the ones of solid samples. At last, the thermal insulation properties were discussed accordingly.

The fabrication of flexible and oxygen barrier cellulose nanofiber/polylactic acid nanocomposites using cosolvent system

AbstractThe main disadvantages of polylactic acid (PLA) for food packaging applications are its brittleness and poor gas barrier properties. The purpose of this study is to evaluate the potential usability of triethyl citrate (TEC) and cellulose nanofiber (CNF) in PLA to obtain bio‐based films with optimal properties. The incorporation of CNF as reinforcement fillers in polymer matrix has long been debated due to its difficulties to disperse uniformly in hydrophobic polymer matrix attribute to their hydrophobic nature. In order to overcome this problem, different feeding method for CNF into the mixer was studied, and CNF/PLA nanocomposites were characterized. It was found that CNF was successfully dispersed in the PLA matrix through the TEC‐CNF suspension, which greatly improved tensile strength and flexibility of the CNF/PLA nanocomposites. The oxygen barrier property was enhanced up to 47.3% (16.99 cc·mm/m2·day·atm) with the increase loading of 0.25, 0.50, and 1 wt% of CNF. Moreover, the dynamic mechanical analysis showed that the low tan delta peak of CNF/PLA nanocomposites (48.25°C) was shifted to high peak (52.99°C) due to incorporation of TEC; indicates an improved of thermal stability of the composites. Overall, the t‐CNF/PLA nanocomposites show a great feasibility for various eco‐friendly flexible packaging applications.

Nanocomposites membranes from cellulose nanofibers, SiO2 and carboxymethyl cellulose with improved properties

The binary nanocomposites blended by carboxymethyl cellulose (CMC) and SiO2 nanoparticles were constructed to prepare the films with superior thermal stability and flame retardant properties. The incorporation of cellulose nanofibers(CNFs) and SiO2 nanoparticles were followed to prepare ternary nanocomposite films exhibiting excellent mechanical properties. The mechanism and chemical reaction of the thermal decomposition for the CMC/SiO2 composite membrane were proposed, which showed that the mass residuals were Na2CO3, SiO2 and Na2SiO3, Na2CO3 when the content of the SiO2 nanoparticles was lowered and higher than 9.6 %, respectively. Compared with the pure CMC, micro combustion calorimeter (MCC) showed that the total heat release (THR) and the peak heat release rate (PHRR) both decreased from 6.4 kJ/g to 5.8 kJ/g, 134 w/g to 27 w/g, respectively. Moreover, mechanical properties of CMC/CNFs/SiO2 membrane showed that the toughness and rigidity of the nanocomposites increased by 56.0 % and 63.0 % on the basis of CMC, respectively.

Preparation and characterization of whey protein isolate/polydextrose-based nanocomposite film incorporated with cellulose nanofiber and L. plantarum: A new probiotic active packaging system

There is growing interest in bioactive packaging systems due to their potential for extending the shelf life of food products. In this regard, the aim of this study was to prepare cellulose nanofiber (CNF) and polydextrose incorporated whey protein isolate (WPI) based probiotic nanocomposite film containing Lactobacillus plantarum. The prepared film samples were characterized by FT-IR, FE-SEM, DSC and XRD analyses. The results revealed good compatibility between WPI matrix, CNF and polydextrose, such that CNF and polydextrose had no adverse effect on the morphological and thermal properties and the crystallinity of WPI-based probiotic films. Furthermore, the CNF and polydextrose incorporated WPI-based films exhibited low water vapor permeability and good mechanical properties. The viability of probiotic bacteria was significantly (p < 0.05) enhanced following the incorporation of CNF and polydextrose during the storage time. Moreover, the probiotic film containing 5 g/100 g CNF and 20 g/100 g polydextrose exhibited inhibition zones against P. aeruginosa (14.6 ± 0.5 mm), S. aureus (14.0 ± 1.0 mm), and E. coli (12.6 ± 0.5 mm) bacteria. In conclusion, the CNF and polydextrose incorporated WPI-based probiotic nanocomposite film can be applied in bioactive food packaging system owing to its unique features.

Effect of nano-cellulosic fiber on mechanical and barrier properties of polylactic acid (PLA) green nanocomposite film

Most of the packaging products are made up of non-biodegradable materials resulting in environmental pollution, so the materials derived from natural resources such as polylactic acid and cellulose nanofibers have been strongly advocated as potential material for packaging application. In this work, optically transparent green nanocomposite films were prepared by the incorporation of cellulose nanofibers (1, 3, 5 wt%) into the polylactic acid (PLA) matrix using a cost-effective solvent casting method. The resulting green nanocomposite films were evaluated for morphology, structural and, thermal properties by Scanning electron microscopy (SEM), x-ray diffraction (XRD), and Thermogravimetric analysis (TGA/DTG). The Cellulose nanofibers (CNFs) prepared by directly treating the jute fiber with HNO3–NaNO2 mixture resulted in CNFs diameter of 4–6 nm and length of several micrometers. SEM results revealed the uniform dispersion of CNFs into the PLA matrix. The incorporation of CNFs improved the physical properties, such as mechanical and barrier properties (Water vapor transmission rate and oxygen permeability) of the prepared nanocomposite films. Specifically, a higher loading of 5 wt% of CNFs in the PLA matrix enhanced the barrier and mechanical properties of the nanocomposite film compared to those of the pristine PLA films. Furthermore, the prepared nanocomposite films were optically transparent and thermally stable. These results demonstrate the use of HNO3–NaNO2 Oxidized CNFs in PLA matrix that makes it possible to produce nanocomposite film that has potential in packaging application.

Cellulose nanofiber-multilayered fruit peel-mimetic gelatin hydrogel microcapsules for micropackaging of bioactive ingredients

We report a facile but robust approach to fabricate fruit peel-mimetic microcapsules (FPMCs) of which shell was structured by layering cellulose nanofibers (CNFs) with an antioxidant and a waxy compound on monodisperse gelatin microparticles using the layer-by-layer deposition. The thickness and moduli of the shell increased commonly depending on the number of CNF layers, indicating that the incorporation of CNFs made the shell layer rigid. We determined that the coating of the outermost FPMC layer with dodecane nanoemulsions softened the shell surface, thus preventing the generation of microcracks, which is essential for minimizing dehydration in the drying process. Furthermore, we also confirmed that the co-deposition of a phenolic compound, gallic acid, which is encapsulated in the polymeric micelles, with the shell layers allowed the FPMCs to exert antioxidant effects against the influx of oxygen from the atmosphere. These results highlight that our FPMC system could pave the way for the development of a micropackaging technology that enables encapsulation and stabilization of bioactive ingredients.

Effect of cellulose nanofiber content on flexural properties of a model, thermoplastic, injection-molded, polymethyl methacrylate denture base material

Cellulose nanofiber (CNF) made from wood-derived fiber is considered as a potential alternative reinforcing material to conventional fibers. The aim of this study was to investigate the effect of CNF on the flexural properties of CNF-reinforced, injection molded, polymethyl methacrylate (PMMA) denture base material. Test specimens were fabricated from a model thermoplastic denture base resin using the injection molding technique. The resin pellets were mixed with CNF (to obtain different weight percentages 5, 10, 15, and 23 wt%). PMMA without CNF served as the control (0 wt%). Prior to the testing, the test specimens (n = 12/group) were water-immersed at 37 °C water for 50 h. The flexural strengths and moduli of the specimens were determined using three-point bending tests. Statistical evaluation included a one-way analysis of variance and the Student-Newman-Keuls test (α = 0.05). The mean and standard deviation of flexural strengths with the addition of 0, 5, 10, 15 and 23% CNF were 49.4 (±0.7), 56.4 (±1.3), 63.5 (±2.0), 72.0 (±4.7), and 96.8 (±4.0) MPa, respectively. The mean and standard deviation of flexural modulus with the addition of the same concentrations of CNF were 1.31 (±0.02), 1.56 (±0.05), 1.99 (±0.14), 2.40 (±0.15), and 3.96 (±0.08) GPa, respectively. The flexural strengths and moduli of the CNF-reinforced PMMA were significantly higher than those of pure PMMA (p < 0.05). Hence, incorporation of CNF can significantly improve flexural properties of a thermoplastic PMMA denture base material.

Synthesis and Characterization of a High Flux Nanocellulose-Cellulose Acetate Nanocomposite Membrane.

Despite the advantages of membrane processes, their high energy requirement remains a major challenge. Fabrication of nanocomposite membranes by incorporating various nanomaterials in the polymer matrix has shown promise for enhancing membrane flux. In this study, we embed functionalized cellulose nanofibers (CNFs) with high aspect ratios in the polymer matrix to create hydrophilic nanochannels that reduce membrane resistance and facilitate the facile transport of water molecules through the membrane. The results showed that the incorporation of 0.1 wt % CNF into the polymer matrix did not change the membrane flux (~15 ) and Bovine Serum Albumin (BSA) Fraction V rejection, while increasing the CNF content to 0.3 wt % significantly enhanced the flux by seven times to ~100 , but the rejection was decreased to 60–70%. Such a change in membrane performance was due to the formation of hydrophilic nanochannels by the incorporation of CNF (corroborated by the SEM images), decreasing the membrane resistance, and thus enhancing the flux. When the concentration of the CNF in the membrane matrix was further increased to 0.6 wt %, no further increase in the membrane flux was observed, however, the BSA rejection was found to increase to 85%. Such an increase in the rejection was related to the electrostatic repulsion between the negatively-charged CNF-loaded nanochannels and the BSA, as demonstrated by zeta potential measurements. SEM images showed the bridging effect of the CNF in the nanochannels with high CNF contents.