Carboxylated Cellulose Nanofibrils Research Articles

In-situ synthesis and binding of silver nanoparticles to dialdehyde and carboxylated cellulose nanofibrils, and active packaging therewith

AbstractThe present work reveals the potential application of dialdehyde and carboxylated nanocellulose for the in-situ reduction of Ag+ and immobilization as silver nanoparticles (AgNPs) on cellulose surfaces. Tollens’ reagent (Ag(NH3)2OH) at concentrations ranging from 5·10–3 to 10–1 M was incorporated in both dialdehyde cellulose (DAC) and dialdehyde-modified TEMPO-oxidized cellulose nanofibers (DA-TOCNFs). The results showed that DA-TOCNFs facilitated faster reduction of Ag+ and effective immobilization of AgNPs on the nanocellulose surface. The resulting suspensions exhibited stability and demonstrated strong antimicrobial activity against Bacillus subtilis when coated on paper surfaces. Importantly, the coated papers did not show significant silver migration to food simulants B (3 vol% acetic acid) and D1 (ethanol/water mixture, 50 vol%), indicating the potential of these suspensions for active food packaging. The advantages of using DA-TOCNFs over DAC were attributed to their higher cationic demand and ζ-potential, resulting in a higher density of binding sites. Moreover, the charged and entangled network of DA-TOCNFs allowed for the individualization of AgNPs, unlike DAC, where some agglomerations were observed. Overall, this study presents an improved single-step process for the synthesis of AgNPs on nanocellulose surfaces, highlighting their potential for safe and high-performance applications in food packaging. Paper sheets coated with nanocellulose/AgNPs suspensions fully inhibited the growth of B. subtilis, at least for one month after coating, and caused damage to their cell membranes. This research provides a one-pot facile route to fabricating hybrid nanocellulose/AgNPs systems, stable in water, and may be used directly as a coating layer for board and paper active packaging with little or even undetectable release of Ag.

Characterization of carboxylated cellulose nanofibrils and oligosaccharides from Kraft pulp fibers and their potential elicitor effect on the gene expression of Capsicum annuum

Biomass-derived oligo- and polysaccharides may act as elicitors, i.e., bioactive molecules that trigger plant immune responses. This is particularly important to increase the resistance of plants to abiotic and biotic stresses. In this study, cellulose nanofibrils (CNF) gels were obtained by TEMPO-mediated oxidation of unbleached and bleached kraft pulps. The molecular structures were characterized with ESI and MALDI MS. Analysis of the fine sequences was achieved by MS and MS/MS of the water-soluble oligosaccharides obtained by acid hydrolysis of the CNF gels. The analysis revealed the presence of two families: one corresponding to homoglucuronic acid sequences and the other composed by alternating glucose and glucuronic acid units. The CNF gels, alone or with the addition of the water-soluble oligosaccharides, were tested on Chili pepper (Capsicum annuum). Based on the characterization of the gene expression with Next Generation Sequencing (NGS) of the C. annuum's total messenger RNA, the differences in growth of the C. annuum seeds correlated well with the downregulation of the pathways regulating photosynthesis. A downregulation of the response to abiotic factors was detected, suggesting that these gels would improve the resistance of the C. annuum plants to abiotic stress due to, e.g., water deprivation and cold temperatures.

Carboxylated cellulose nanofibrils based on banana rachis as additive in oil-based emulsion coolant for effective flank wear reduction in lathe operation

Nitro-oxidized carboxylated cellulose nanofibrils (NOCNFs) from the banana rachis are employed in oil-emulsion coolant as an additive. The concentrations of NOCNF were 0.1, 0.2, 0.3 wt. %. The cutting parameters include the spindle speeds and depth of cut. The temperature and wear reduction were significant. The temperature at the tool flank decreased from 119°C to 76°C, corresponding to an 11% reduction in wear at the depth of cut co. 2 mm and spindle speed of 1330 rpm. The viscosity of the nanofluid and the corrosion of the low-carbon mild steel specimen are discussed. Arguably, a stable NOCNF nanofluid suspension is good against wear even at elevated temperatures. Interestingly, these results occurred at a lower NOCNF concentration co. 0.3% wt. compared to 1–2 wt. % from Al2O3 nanoparticles in literature. In this paper, banana rachis nanofibrils are attractive for developing of effective and environmentally friendly additives from biomass.

Regioselectively Carboxylated Cellulose Nanofibril Models from Dissolving Pulp: C6 via TEMPO Oxidation and C2,C3 via Periodate-Chlorite Oxidation.

Regioselective C6 and C2,C3 carboxylated cellulose nanofibrils (CNFs) have been robustly generated from dissolving pulp, a readily available source of unmodified cellulose, via stoichiometrically optimized 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO)-mediated and sequential sodium periodate-sodium chlorite (PC) oxidation coupled with high-speed blending. Both regioselectively optimized carboxylated CNF series possess the widest ranges of comparable charges (0.72-1.48 mmol/g for T-CNFs vs. 0.72-1.10 mmol/g for PC-CNFs), but similar ranges of thickness (1.3-2.4 nm for T-CNF, 1.8-2.7 nm PC-CNF), widths (4.6-6.6 nm T-CNF, 5.5-5.9 nm PC-CNF), and lengths (254-481 nm T-CNF, 247-442 nm PC-CNF). TEMPO-mediated oxidation is milder and one-pot, thus more time and process efficient, whereas the sequential periodate-chlorite oxidation produces C2,C3 dialdehyde intermediates that are amenable to further chemical functionalization or post-reactions. These two well-characterized regioselectively carboxylated CNF series represent coherent cellulose nanomaterial models from a single woody source and have served as references for their safety study toward the development of a safer-by-design substance evaluation tool.

Characterization and Antifungal Activity of Lemongrass Essential Oil-Loaded Nanoemulsion Stabilized by Carboxylated Cellulose Nanofibrils and Surfactant.

Nanocellulose is an emerging green, biodegradable and biocompatible nanomaterial with negligible toxicities. In this study, a carboxylated nanocellulose (i.e., 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO)-oxidized cellulose nanofibril (TEMPO-CNF)) was prepared from corn stover and characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA). Corn stover-derived TEMPO-CNF was explored as an emulsion co-stabilizer together with Tween 80 for lemongrass essential oil-loaded emulsions. Droplet size, phase behavior and thermodynamic stability of oil-in-water emulsions stabilized by Tween 80 and TEMPO-CNF were investigated. The optimal nanoemulsion stabilized by this binary stabilizer could achieve a mean particle size of 19 nm, and it did not form any phase separation against centrifugal forces, freeze-thaw cycles and at least 30 days of room temperature storage. The nanoencapsulated essential oil had better inhibition activity against the mycelial growth of Aspergillus flavus than pure essential oil. Results from this study demonstrate the potential of using agricultural byproduct-derived nanomaterial as nanoemulsion stabilizers for essential oils with good emulsion thermodynamic stability as well as enhanced antifungal activities.

Cost-effective preparation of highly amorphous cellulose nanofibrils with TEMPO oxidation promoted by mild molten salt hydrate pretreatment

2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)/NaBr/NaClO catalytic oxidation system is a commonly used method to prepare carboxylated cellulose nanofibrils (TOCNF), but the traditional reaction system is relatively time consuming with high production cost. Herein, a facile and clean process of lithium bromide trihydrate (LBTH) pretreatment of hardwood dissolving pulp (HDP) was conducted, which promoted the reaction and reduced the use of chemicals for TEMPO oxidation. Characterizations verified that the LBTH pretreatment could significantly improve the efficiency of the subsequent TEMPO oxidation of HDP. Particularly, the obtained TEMPO-oxidized cellulose nanofibrils (TOCNF) had highly amorphous structure, the carboxyl content (1.06 mmol/g) of the obtained TOCNF with LBTH pretreatment for 5 min could increase by 58%, and the corresponding oxidation time was shortened by 57%, compared to the unpretreated HDP. Moreover, the fabricated TOCNF with increased carboxyl content exhibited strong ability to stabilize high internal phase Pickering emulsions (HIPPEs) with analogous average particle sizes. Additionally, LBTH solvent could be easily recovered, and the recycling does not affect the effectiveness of LBTH pretreatment. Compared to the unpretreated HDP, the operation cost of TEMPO-mediated oxidation could be reduced by 31% with the LBTH pretreatment. This work has potential to boost the commercial production and application of TOCNF and nanocellulose-based materials.

Simultaneously flame-retardant and antibacterial films from κ-carrageenan/carboxylated cellulose nanofibril/phytic acid for the preservation of cooked pork

Conventional polysaccharide films are flammable and susceptible to bacterial growth, decreasing the potential in practical applications such as bio-based and active food packaging. In this study, the nontoxic naturally occurring compound phytic acid (PA) was introduced to a blended film of κ-carrageenan (κC) and carboxylated cellulose nanofibrils (CCNF) to overcome these disadvantages. Compared with the κC-CCNF-PA0 film, the κC-CCNF-PA24 film possessed improved elongation at break (41%), water vapor permeability (3.46 g m−1 Pa−1 s−1 × 10−8) and oxygen permeability (1.50 cm3 mm−2 Pa−1 day−1 × 10−12). Thermogravimetric analysis, limiting oxygen index and actual flame-burning behaviors revealed good flame retardancy of the prepared films with the increase in PA. When the PA content reached 18% and 9%, the antibacterial rate against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) reached 100%, respectively. The cooked pork samples packaged by κC-CCNF-PA24 exhibited lower values of malondialdehyde (0.61 mg kg−1) and total viable count (8 CFU g−1) compared with those by κC-CCNF-PA0 film (0.99 mg kg−1, 447 CFU g−1). On the basis of these results, we believe that the sustainable and clean strategy provides an opportunity to improve and functionalize very brittle and flammable polysaccharide-based films.

Нуклеация гидрата метана в присутствии нанофибриллярной целлюлозы

Is it possible to slow down gas hydrate nucleation by introducing additional surfaces into the system? This process usually occurs at phase boundaries, i.e., the appearance of new surfaces (solid particles) in the system should rather increase the probabilityof hydrate formation. In this work, the effect of carboxylated cellulose nanofibrils (CNF) dispersed in water on the formationof methane hydrate under intensive stirring was investigated. It was found that, under identical conditions, 0.5 mass% CNF allowed reducing the hydrate nucleation rate and suppressing the "memory" effect characteristic for hydrate formation from distilled water (DW). The analysis of the "survival" functions revealed that the mechanism of the CNF inhibitory action is to reduce the number of hydrate nucleation centers. This can be explained by the participation of CNF in the disturbance of the hydrogen bond network:for example, mechanical "destruction" of pre-critical nuclei by inhibitor particles under intensive stirring. The data obtained suggest the development of a new class of kinetic hydrate inhibitors based on dispersions.

The Impact of Surface Charges of Carboxylated Cellulose Nanofibrils on the Water Motions in Hydrated Films.

Cellulose nanofibrils (CNFs) with carboxylated surface ligands are a class of materials with tunable surface functionality, good mechanical properties, and bio-/environmental friendliness. They have been used in many applications as scaffold, reinforcing, or functional materials, where the interaction between adsorbed moisture and the CNF could lead to different properties and structures and become critical to the performance of the materials. In this work, we exploited multiple experimental methods to study the water movement in hydrated films made of carboxylated CNFs prepared by TEMPO oxidation with two different surface charges of 600 and 1550 μmol·g–1. A combination of quartz crystal microbalance with dissipation (QCM-D) and small-angle X-ray scattering (SAXS) shows that both the surface charge of a single fibril and the films’ network structure contribute to the moisture uptake. The films with 1550 μmol·g–1 surface charges take up twice the amount of moisture per unit mass, leading to the formation of nanostructures with an average radius of gyration of 2.1 nm. Via the nondestructive quasi-elastic neutron scattering (QENS), a faster motion is explained as a localized movement of water molecules inside confined spheres, and a slow diffusive motion is found with the diffusion coefficient close to bulk water at room temperature via a random jump diffusion model and regardless of the surface charge in films made from CNFs.

In-situ growth of porous Cu3(BTC)2 on cellulose nanofibrils for ultra-low dielectric films with high flexibility

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 [Cu3(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 [email protected] through in-situ growth of CuBTC on CNF surface endowed the ANF/[email protected] 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 °C − 1) and increased water contact angle (83.81°). More interestingly, the removal of guest molecules from the ANF/[email protected] 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.

One-step hydrolysis for the preparation of carboxylated cellulose nanofibrils with highly stable dispersibility from pomelo peel

One-step hydrolysis for the preparation of carboxylated cellulose nanofibrils with highly stable dispersibility from pomelo peel

Oxygenated Nanocellulose-A Material Platform for Antibacterial Wound Dressing Devices.

Both carboxylated cellulose nanofibrils (CNF) and dissolved oxygen (DO) have been reported to possess antibacterial properties. However, the combination for use as wound dressings against biofilm infections in chronic wounds is less known. The present study reports the development of oxygenated CNF dispersions that exhibit strong antibacterial effect. Carboxylated CNF dispersions with different oxidation levels were oxygenated by the OXY BIO System and tested for antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus. The results reveal that the higher oxidation level of the CNFs, the better antibacterial effect. Scanning electron microscopy of bacterial biofilms revealed that a potential mechanism of action of the CNFs is the formation of a network surrounding and entrapping the bacteria. This effect is further potentiated by the oxygenation process. A CNF sample (concentration 0.6 wt %) that was oxygenated to a DO level of 46.4 mg/L demonstrated a strong antibacterial effect against S. aureusin vivo using a mouse model of surgical site infection. The oxygenated CNF dispersion reduced the bacterial survival by 71%, after 24 h treatment. The potent antibacterial effect indicates that oxygenated nanocellulose is a promising material for antibacterial wound dressings.

Fabricating an anti-shrinking κ-carrageenan/sodium carboxymethyl starch film by incorporating carboxylated cellulose nanofibrils for fruit preservation

A stronger and dimension-stabilized film was obtained using κ-carrageenan and sodium carboxymethyl starch (CMS) with carboxylated cellulose nanocrystals (C-CNC) as a reinforcing agent and anti-shrinkage agent. C-CNC endowed the films with better mechanical properties as well as excellent dimensional stability. The film solutions showed shear thinning and acted as a pseudoplastic fluid. When C-CNC content was increased from 0% to 12%, the tensile strength and elongation at break of the films improved from 23.89 MPa to 38.37 MPa and 21.00% to 27.31%, respectively. The films maintained good thermal stability and barrier performance. The Zeta potential of the film suspension can reach below −30 mV, indicating C-CNC enhanced the electrostatic repulsion in the film-forming system, which favored the network structure more continuous and stable. By virtue of the excellent mechanical properties and dimensional stability, strawberries can be tightly wrapped without cracks by the coatings to delay the deterioration greatly. By comparing the weight loss rate, Vc, total soluble solid, hardness, titratable acid and pH, CCC12-coated strawberries were closer to fresh ones. Therefore, this study has developed a feasible, low-cost and green fruit coating that can be potentially utilized on a large-scale.

Self-Assembled Polyester Dendrimer/Cellulose Nanofibril Hydrogels with Extraordinary Antibacterial Activity.

Cationic dendrimers are intriguing materials that can be used as antibacterial materials; however, they display significant cytotoxicity towards diverse cell lines at high generations or high doses, which limits their applications in biomedical fields. In order to decrease the cytotoxicity, a series of biocompatible hybrid hydrogels based on cationic dendrimers and carboxylated cellulose nanofibrils were easily synthesized by non-covalent self-assembly under physiological conditions without external stimuli. The cationic dendrimers from generation 2 (G2) to generation 4 (G4) based on trimethylolpronane (TMP) and 2,2-bis (methylol)propionic acid (bis-MPA) were synthesized through fluoride promoted esterification chemistry (FPE chemistry). FTIR was used to show the presence of the cationic dendrimers within the hybrid hydrogels, and the distribution of the cationic dendrimers was even verified using elemental analysis of nitrogen content. The hybrid hydrogels formed from G3 and G4 showed 100% killing efficiency towards Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) with bacterial concentrations ranging from 105 CFU/mL to 107 CFU/mL. Remarkably, the hybrid hydrogels also showed good biocompatibility most probably due to the incorporation of the biocompatible CNFs that slowed down the release of the cationic dendrimers from the hybrid hydrogels, hence showing great promise as an antibacterial material for biomedical applications.

Development of eco-friendly CO2-responsive cellulose nanofibril aerogels as “green” adsorbents for anionic dyes removal

A novel CO2-responsive cellulose nanofibril aerogel as a “green” adsorbent derived from poly(methacrylic acid-co-2-(dimethylamino) ethyl methacrylate) and carboxylated cellulose nanofibrils was successfully prepared via stepwise cation-induced gelation and freeze drying method. This aerogel exhibited CO2-triggered adsorption behavior towards anionic dyes with a rapid adsorption rate and a high adsorption capacity, as well as satisfactory mechanical properties. Upon CO2 stimulation, the charged aerogel can selectively adsorb anionic dyes from aqueous solutions based on an electrostatic interaction. The maximum adsorption capacities of this aerogel towards methyl blue (MB), naphthol green B (NGB), and methyl orange (MO) were 598.8, 621.1 and 892.9 mg g−1, respectively, accompanied by fast adsorption equilibriums towards MB and NGB within 7 min, and MO within 12 min. Meanwhile, the adsorption isotherms and the kinetics of the CO2-responsive adsorbents followed the Freundlich isotherm and the pseudo-second-order model, respectively. Furthermore, the resulting CO2-responsive adsorbent exhibited outstanding recyclability, as its adsorption performance can still be maintained even after twenty cycles. Accordingly, the resultant CO2-responsive cellulose nanofibril aerogel could be a promising adsorbent material for the removal of anionic dyes in wastewater remediation.

Multivalent ion-induced re-entrant transition of carboxylated cellulose nanofibrils and its influence on nanomaterials' properties.

In this work, we identify and characterize a new intriguing capability of carboxylated cellulose nanofibrils that could be exploited to design smart nanomaterials with tuned response properties for specific applications. Cellulose nanofibrils undergo a multivalent counter-ion induced re-entrant behavior at a specific multivalent metal salt concentration. This effect is manifested as an abrupt increase in the strength of the hydrogel that returns upon a further increment of salt concentration. We systematically study this phenomenon using dynamic light scattering, small-angle X-ray scattering, and molecular dynamics simulations based on a reactive force field. We find that the transitions in the nanofibril microstructure are mainly because of the perturbing actions of multivalent metal ions that induce conformational changes of the nanocellulosic chains and thus new packing arrangements. These new aggregation states also cause changes in the thermal and mechanical properties as well as wettability of the resulting films, upon water evaporation. Our results provide guidelines for the fabrication of cellulose-based films with variable properties by the simple addition of multivalent ions.

Bioinspired 3D printable pectin-nanocellulose ink formulations

The assessment of several ink formulations for 3D printing based on two natural macromolecular compounds is presented. In the current research we have exploited the fast crosslinking potential of pectin and the remarkable shear-thinning properties of carboxylated cellulose nanofibrils, which is known to induce a desired viscoelastic behavior. Prior to 3D printing, the viscoelastic properties of the polysaccharide inks were evaluated by rheological measurements and injectability tests. The reliance of the printing parameters on the ink composition was established through one-dimensional lines printing, the base units of 3D-structures. The performance of the 3D-printed structures after ionic cross-linking was evaluated in terms of mechanical properties and rehydration behavior. MicroCT was also used to evaluate the morphology of the 3D-printed objects regarding the effect of pectin/nanocellulose ratio on the geometrical features of scaffolds. The proportionality between the two polymers proved to be the determining factor for the firmness and strength of the printed objects.

Preparation and characterization of carboxylated cellulose nanofibrils with dual metal counterions

Surface C6-carboxylated cellulose nanofibrils (TCNF-COONa) were prepared from wood cellulose by TEMPO/NaBr/NaClO oxidation in water at pH 10 and successive mechanical disintegration of the oxidized cellulose in water. Aqueous TCNF dispersions with magnesium and calcium carboxylate groups, TCNF-COOMg and TCNF-COOCa, respectively, were prepared in high yields of 85–90% from aqueous TCNF-COONa dispersion by addition of aqueous MgCl2 and CaCl2 solutions, respectively, to the aqueous TCNF-COONa dispersion, washing the gels with water by filtration without drying, and successive mechanical disintegration of the gels in water. The cast-dried TCNF-COONa, TCNF-COOMg, and TCNF-COOMg films had no significant differences in density and water content at 23 °C and 50% relative humidity. Consequently, they had similar mechanical properties. Aqueous TCNF-COONa/Mg and TCNF-COONa/Ca dispersions were prepared by mixing TCNF-COONa and either TCNF-COOMg or TCNF-COOCa dispersion at a weight ratio of 1:1. Oxygen permeabilities of the TCNF-COONa/Mg and TCNF-COOCa films had the lowest and highest values at 50% RH, respectively, while those of the TCNF-COOMg and TCNF-COONa/Ca films had the lowest and highest values at 80%, respectively. The Na and Mg counterions in the aqueous TCNF-COONa/Mg dispersion were homogeneously distributed in each TCNF element without separately keeping individual TCNF-COONa and TCNF-COOMg elements.

Preparation of Self-supporting Bagasse Cellulose Nanofibrils Hydrogels Induced by Zinc Ions.

Cellulose hydrogels are often prepared from native cellulose through a direct cellulose dissolution approach that often involves tedious process and solvent recovery problems. A self-supporting cellulose hydrogel was prepared by gelation of the TEMPO-oxidized bagasse cellulose nanofibrils (CNF) triggered by strong crosslinking between carboxylate groups and Zn2+. TEMPO process was used to generate negatively charged carboxylate groups on CNF surface to provide a high binding capability to Zn2+. Three TEMPO-oxidized CNFs of different carboxylate contents were prepared and characterized. TEM and AFM microscopes suggested that the sizes of CNFs were fined down and carboxylated cellulose nanofibrils (TOCNFs) of 5–10 nm wide, 200–500 nm long, and carboxylate contents 0.73–1.29 mmol/g were obtained. The final structures and compressive strength of hydrogels were primarily influenced by interfibril Zn2+-carboxylate interactions, following the order of TOCNFs concentration > content of carboxylate groups > concentration of zinc ions. A CO2 sensitive self-supporting cellulose hydrogel was developed as a colorimetric indicator of food spoilage for intelligent food packaging applications.

Synthesis of Nanofibrillated Cellulose by Combined Ammonium Persulphate Treatment with Ultrasound and Mechanical Processing

Ammonium persulfate has been known as an agent for obtaining nanocellulose in recent years, however most research has focused on producing cellulose nanocrystals. A lack of research about combined ammonium persulfate oxidation and common mechanical treatment in order to obtain cellulose nanofibrils has been identified. The objective of this research was to obtain and investigate carboxylated cellulose nanofibrils produced by ammonium persulfate oxidation combined with ultrasonic and mechanical treatment. Light microscopy, atomic force microscopy (AFM), powder X-Ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Zeta potential measurements were applied during this research. The carboxylated cellulose suspension of different fractions including nanofibrils, microfibrils and bundles were produced from bleached birch Kraft pulp fibers using chemical pretreatment with ammonium persulfate solution and further defibrillation using consequent mechanical treatment in a high shear laboratory mixer and ultrasonication. The characteristics of the obtained nanofibrils were: diameter 20–300 nm, crystallinity index 74.3%, Zeta potential −26.9 ± 1.8 mV, clear FTIR peak at 1740 cm−1 indicating the C=O stretching vibrations, and lower thermostability in comparison to the Kraft pulp was observed. The proposed method can be used to produce cellulose nanofibrils with defined crystallinity.