Method and composition for using charged cellulosic fibrils produced via nitro- oxidation process to stabilize and suspend active ingredients in agricultural and industrial formulations

Abstract

A pesticide formulation includes a pesticide active ingredient, nitro-oxidized cellulose nanofibers (NOCNFs), and water. The NOCNFs can have a degree of oxidation between about 0.8–about 3.0 mmol –COOH / g. The NOCNFs can include a counterion selected from the group including sodium, potassium, ammonium, or a combination thereof. The NOCNFs can be included in a range of about 0.01 wt%–about 5 wt%.

Description

Attorney Docket No. 201291.7. PCTMETHOD AND COMPOSITION FOR USING CHARGED CELLULOSIC FIBRILS PRODUCED VIA NITRO- OXIDATION PROCESS TO STABILIZE AND SUSPEND ACTIVE INGREDIENTS IN AGRICULTURAL AND INDUSTRIAL FORMULATIONSCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Patent Application No. 63 / 695,488 filed on September 17, 2024. The entire contents of each application are hereby incorporated by reference.BACKGROUND OF THE INVENTION1. Field of the Invention

[0002] The present invention relates to the field of agricultural and industrial formulations, specifically to the use of charged cellulosic fibrils produced through a Nitro-Oxidation Process (NOP) or any other suitable process for stabilizing and suspending active chemical ingredients in formulations, such as pesticides, herbicides, fertilizers, coatings, adhesives, and other industrial applications.2. Description of the Related Art

[0003] Traditional agricultural and industrial formulations, including pesticides, herbicides, fungicides, and fertilizers, often rely on synthetic surfactants and toxic petroleum solvents to achieve adequate dispersion and suspension of active ingredients. While effective at achieving suspension and delivery, these additives often contribute to significant environmental burdens, including soil and water contamination, toxicity to non-target organisms, and persistence in ecosystems. These additives can also pose direct health hazards to workers and end-users through inhalation, dermal exposure, or residue accumulation. Increasing regulatory restrictions and consumer demand for safer, sustainable solutions have further intensified the need for alternatives that maintain product performance while reducing ecological and human health risks. There is an increasing need for sustainable and safer alternatives that maintain or enhance the efficacy of these products while reducing their environmental footprint.SUMMARY OF THE INVENTION

[0004] To overcome the problems described above, example embodiments of the present invention provide nitro-oxidized cellulose nanofiber (NOCNF)-based pesticide formulations that provide an effective platform for stabilizing and enhancing the performance of pesticide active ingredients. By using charged cellulosic fibrils, such as NOCNF, optionally in combination with pH adjustment or surfactant additives, pesticide formulations achieve improved dispersion, controlled surface tension, reduced contact angles, and enhanced adhesion to hydrophobic plant surfaces. These effects translate into more uniform spray coverage, increased water retention, and sustained uptake of the active ingredient into plant tissues.

[0005] Agricultural formulations can include NOCNFs as multifunctional stabilizing and performance-enhancing agents for pesticide active ingredients. Traditional pesticide formulations rely heavily on organic solvents, synthetic surfactants, or oils to disperse and stabilize hydrophobic actives, leading to environmental, regulatory, and safety concerns. Example embodiments of the present invention address these challenges by providing aqueous formulations in which CNF, optionally in combination with surfactants or pH adjustment, enables improved solubilization, dispersion, wetting, adhesion, and retention of active ingredients of pesticides on plant surfaces.

[0006] Biopolymer-based stabilizers have emerged as a promising class of materials capable of addressing the challenges discussed above. In particular, carboxylated nanocellulose and other charged cellulosic fibrils have been recognized for their potential in stabilizing formulations due to their unique surface properties and ability to form networks in aqueous formulation. Due to their high aspect ratio, surface charge density, and ability to form percolated networks, these charged cellulosic fibrils can impart shear-thinning viscosity, enhance suspension stability, and prevent phase separation. These materials can interact with active ingredients through electrostatic forces, Van der Waals forces and hydrogen bonding, thereby minimizing the need for hazardous solvents and surfactants.

[0007] Various processes exist for producing such charged cellulosic fibrils. Particularly efficient and scalable methods include Nitro-Oxidation Processes (NOPs) as disclosed in U.S. Patent No. 10,894,838, PCT Application No. PCT / US2024 / 055838, or PCT Application No.PCT / US2015 / 060261, which introduce carboxyl and other oxygen-containing functional groups onto cellulose chains. These oxygen-containing functional groups not only increase hydrophilicity, but also provide sites for ionic interactions and colloidal stabilization in aqueous environments. Other oxidative or mechanical processes can also be employed to generate charged cellulosic fibrils with similar properties, depending on feedstock, cost considerations, and targeted applications. Regardless of the production pathway, the resulting charged cellulosic fibrils or charged nanocellulose materials offer a renewable, biodegradable, and environmentally benign platform for formulation stabilization. Accordingly, there exists a clear opportunity to develop agricultural and industrial compositions in which charged cellulosic fibrils derived from cellulose serve as multifunctional stabilizers. Such systems can deliver equivalent or superior efficacy compared to conventional solvent-heavy formulations, while significantly reducing their environmental footprint and improving safety profiles.

[0008] In example embodiments of the present invention, the formulations can include salts or derivatives of the pesticide active ingredients, surfactants, such as non-ionic surfactants (e.g., Triton X-100), or pH adjustment agents to enhance solubility and stability. For example, CNF in combination with glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D), or their corresponding salts produce formulations with reduced surface tension, lower contact angle on hydrophobic leaf-mimicking surfaces, and improved foliar wetting relative to conventional formulations.

[0009] Example embodiments of the present invention demonstrate that CNF-containing formulations generate more uniform spray coatings, increase water retention on plant leaves, and provide prolonged availability of the active ingredient(s) for plant uptake. These effects result in improved efficacy, reduced drift, and lower required dosages compared to conventional formulations.

[0010] Example embodiments of the present invention can provide a sustainable, biodegradable, and scalable alternative to conventional solvent- and surfactant-intensive pesticide formulations, offering both environmental and performance advantages.

[0011] According to an example embodiment of the present invention, a pesticide formulation includes a pesticide active ingredient, nitro-oxidized cellulose nanofibers (NOCNFs), and water.

[0012] The pesticide active ingredient can include one or more selected from the group including herbicides, insecticides, or fungicides. The pesticide active ingredient can include one or more selected from the group including glyphosate, 2,4-D, dicamba, atrazine, triclopyr, glufosinate ammonium, paraquat, metolachlor, acetochlor, pendimethalin, sulfentrazone, imidacloprid, clothianidin, thiamethoxam, lambda-cyhalothrin, deltamethrin, permethrin, chlorpyrifos, malathion, fipronil, spinosad, abamectin, azoxystrobin, pyraclostrobin, mancozeb, propiconazole, difenoconazole, tebuconazole, captan, thiophanate-methyl, metalaxyl, sulfur, copper hydroxide, a derivate thereof, or a combination thereof. The pesticide active ingredient can be in an acid, a salt, an ester, an amine, or a derivative form.

[0013] The NOCNFs can have a degree of oxidation between about 0.8-about 3.0 mmol - COOH / g. The NOCNFs can include a counterion selected from the group including sodium, potassium, ammonium, or a combination thereof. The NOCNFs can be included in a range of about 0.01 wt%-about 5 wt%. The NOCNFs can be included in a range of about 0.05 wt%-about 1 wt%.

[0014] The pesticide formulation can further include a surfactant, an oil, an adjuvant, a binder, an antifoaming agent, or a viscosity modifier. The pesticide formulation can further include lignin, hemicellulose, holocellulose, protein, or a fatty acid. The pesticide formulation can have a surface tension in a range of about 30.0 mN / m-about 72.8 mN / m. The viscosity at shear rates below 100 s-1of the pesticide formulation can be at least 5X greater than that of a fibril-free pesticide formulation, while the sprayability of the pesticide formulation can be maintained at shear rates above 500 s-1.

[0015] According to an example embodiment of the present invention, a method of preparing a pesticide formulation includes providing nitro-oxidized cellulose nanofibers (NOCNFs) and mixing the NOCNFs and a pesticide active ingredient in water.

[0016] The method can further include adjusting pH to be between about 3-about 11. The NOCNFs can be provided by producing charged cellulosic fibrils from biomass feedstock by a nitro-oxidation process.

[0017] The pesticide active ingredient can include one or more selected from the group including herbicides, insecticides, or fungicides. The pesticide active ingredient can include one or more selected from the group including glyphosate, 2,4-D, dicamba, atrazine, triclopyr, glufosinate ammonium, paraquat, metolachlor, acetochlor, pendimethalin, sulfentrazone, imidacloprid, clothianidin, thiamethoxam, lambda-cyhalothrin, deltamethrin, permethrin, chlorpyrifos, malathion, fipronil, spinosad, abamectin, azoxystrobin, pyraclostrobin, mancozeb, propiconazole, difenoconazole, tebuconazole, captan, thiophanate-methyl, metalaxyl, sulfur, copper hydroxide, a derivate thereof, or a combination thereof. The pesticide active ingredient can be in an acid, a salt, an ester, an amine, or a derivative form.

[0018] The NOCNFs can have a degree of oxidation between about 0.8-about 3.0 mmol - COOH / g. The NOCNFs can include a counterion selected from the group including sodium, potassium, ammonium, or a combination thereof. The NOCNFs can be included in a range of about 0.01 wt%-about 5 wt%. The NOCNFs can be included in a range of about 0.05 wt%-about 1 wt%.

[0019] The method can further include adding a surfactant, an oil, an adjuvant, a binder, an antifoaming agent, or a viscosity modifier. The pesticide formulation can include lignin, hemicellulose, holocellulose, protein, or a fatty acid. The pesticide formulation can have a surface tension in a range of about 30.0 mN / m-about 72.8 mN / m. The viscosity at shear rates below 100 s-1of the pesticide formulation is at least 5X greater than that of a fibril-free pesticide formulation, while sprayability of the pesticide formulation can be maintained at shear rates above 500 s-1.

[0020] The above and other features, elements, characteristics, steps, and advantages of the present invention will become more apparent from the following detailed description of example embodiments of the present invention with reference to the attached drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The patent or application file contains at least one drawing executed in color. The patent or application file also contains a corresponding black and white line drawing for each of the at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0022] Figs. 1A and IB are photographs showing the dispersion of 2,4- dichlorophenoxyacetic acid (2,4-D) in cellulose nanofiber (CNF) suspension, illustrating the initial mixing behavior. Fig. 1A is in black and white. Fig. IB is in color.

[0023] Figs. 2A and 2B are photographs of glyphosate, glyphosate isopropylamine salt (IPA), 2,4-D and 2,4-D dimethyl amine (DMA) salt-based formulations prepared by mixing with appropriate concentrations (weight %) of cellulose nanofibers (CNF) and / or non-ionic surfactant called Triton X-100. Fig. 2A is in black and white. Fig. 2B is in color.

[0024] Figs. 3A and 3B are photographs showing the effect of pH adjustment on the dispersibility of 2,4-dichlorophenoxyacetic acid (2,4-D) in a cellulose nanofiber (CNF) suspension and showing turbid suspension immediately after mixing (left) and clear solution after pH adjustment to 11 (right). Fig. 3A is in black and white. Fig. 3B is in color.

[0025] Fig. 4 is a graph showing viscosity of 0.1 wt% CNF, 0.1 wt% CNF mixed with 0.16 wt% glyphosate and 0.16 wt% glyphosate in water with varied shear rate.

[0026] Fig. 5 is a graph showing variation of the viscosity of 0.1 wt% CNF, 0.1 wt% CNF mixed with 0.21 wt% glyphosate IPA, and 0.21 wt% glyphosate IPA in water with varied shear rate.

[0027] Figs. 6A and 6B are photographs showing droplet morphology of pesticide formulations on wild lettuce leaves. Fig. 6A is in black and white. Fig. 6B is in color.

[0028] Figs. 7A and 7B are photographs showing a spray test of a formulation containing 2 wt% CNF and 1 wt% 2,4-D FA on sacrificial plant leaves, showing formation of a smooth, thin coating layer that enhances surface contact, improves water retention, and promotes sustained uptake of the active ingredient compared to conventional formulations. Fig. 7A is in black and white. Fig. 7B is in color.

[0029] Figs. 8A and 8B are photographs showing phytotoxicity evaluation of different CNF and 2,4-D-based formulations on tomato plants at Day 0 (Panel A) and Day 14 (Panel B). Fig. 8A is in black and white. Fig. 8B is in color.

[0030] Figs. 9A and 9B are photographs showing phytotoxicity evaluation of CNF and glyphosate-based formulations on tomato plants at Day 0 (Panel A) and Day 14 (Panel B) in Fig. 5. Fig. 9A is in black and white. Fig. 9B is in color.

[0031] Figs. 10A and 10B are photographs showing phytotoxicity of CNF-glyphosate FA formulations on grasses, showing plant appearance at 45 hours ((a)— (c)) and after 14 days ((d)- (f )). The 0.50 wt% CNF + 0.50 wt% glyphosate FA formulation retained more green coloration and appeared less stressed, whereas the 0.25 wt% CNF + 0.50 wt% glyphosate FA formulation showed greater fading, dryness, and reduced density. Fig. 10A is in black and white. Fig. 10B is in color.DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS1. Charged Cellulosic Fibrils Production

[0032] Charged cellulosic fibrils can include nitro-oxidized cellulose nanofibers (NOCNF), other carboxylated cellulose nanofibers (CNF), carboxylated lignin containing cellulosic nanofibers (LCNF), carboxylated cellulose nanocrystals (CNC), or combinations thereof. Charged cellulosic fibrils, including NOCNG, can be produced by an NOP. For example, charged cellulosic fibrils can be made by processing biomass feedstock (woody, non-woody, agricultural residues, or organic waste), either by NOP or alternative oxidation process (e.g., TEMPO, APS, enzymatic, etc.), introducing carboxyl groups to form. The charged cellulosic fibrils can be washed and neutralized to a desired pH (2.5-7.0). Counterion exchange can be performed with sodium hydroxide, ammonium hydroxide, or other bases. The degree of oxidation (DO) of the charged cellulosic fibrils can be in the range of 0.8 mmol-3.0 mmol -COOH / g cellulose. Possible counterions include sodium, potassium, ammonium, calcium, magnesium, or combinations thereof. Sodium-counterion NOCNF can enhance colloidal stability and shelf life, and ammonium-counterion NOCNF enhances compatibility with ammonium-salt herbicides (e.g., glyphosate IPA, 2,4-D DMA) and enhances foliar uptake.

[0033] The charged cellulosic fibrils can have a range of dimensions. For example, NC and CNC typically exhibit lengths from about 100 nm to about several micrometers and diameters of about 5 nm-about 20 nm, within manufacturing and / or measurement tolerances, while CNF and CMF can be longer, with diameters in the range of about 2 nm-about 100 nm, within manufacturing and / or measurement tolerances, depending on the specific production parameters.

[0034] The term "cellulose" denotes a fibrous biomaterial ranging in size from macro to micro to nano and is extractable from various biomass feedstocks and / or natural organic wastes. This cellulose can be mixed with different pesticide active ingredients, including, but not limited to, glyphosate, atrazine, 2,4-D (2,4-Dichlorophenoxyacetic acid), dicamba, glufosinate ammonium, metolachlor, acetochlor, pendimethalin, paraquat, sulfentrazone, etc., to fulfill multiple objectives, such as enhancing their solubility in water, wetting, spreading, controlled delivery, drift reduction, and adjuvancy.

[0035] Charged cellulosic fibrils can be produced using any of the NOPs disclosed in U.S. Patent No. 10,894,838, PCT Application No. PCT / US2024 / 055838, or PCT Application No. PCT / US2015 / 060261. The entire contents of U.S. Patent No. 10,894,838, PCT Application No. PCT / US2024 / 055838, and PCT Application No. PCT / US2015 / 060261 are hereby incorporated by reference. Alternatively, the charged cellulosic fibrils can be made by any other suitable process. NOPs employ various biomass feedstocks, allowing for the utilization of both hard and softwoods, including agricultural residues. Softwoods with low lignin content, specifically agricultural residues, can be used with NOPs.

[0036] In example embodiments of the present invention, biomass feedstocks are sourced from both woody and nonwoody plants, encompassing agricultural residues and natural fibers. These biomass feedstock include materials derived from jute, palm trees, sugarcane bagasse, corn, wheat, oats, rice, sorghum, oil palm, bamboo, spinifex, coastal bermudagrass, miscanthus, switchgrass, azolla, seaweeds, flax, hemp, ramie, kenaf stalk fiber, kenaf core, abaca, sisal, pineapple, banana leaf, banana peel, banana fiber, curaua, lotus leaf stalk, roselle, seed hair fiber, cotton fiber, kapok fiber, areca nut fiber, coconut, potato, cabbage, tomato, rubberwood,Indian screw tree, achira fiber, citrus, soybean, soybean straw, spent grain, soy hull, pea hull, grape pomace, fruit pomace, manures and various combinations thereof.

[0037] The cellulose extraction is not limited to plant sources and can also be derived from bacteria, algae, tunicate, or various combinations thereof. The growing medium may encompass one or more cellulose components. The term "cellulose components" includes cellulose nanofibers CNF, cellulose nanocrystals (CNC), tunicate cellulose, bacterial cellulose, or their amalgamation.

[0038] Natural organic waste means food waste, green waste, fruits and vegetable wastes, meat and fish wastes including the bones, food-soiled paper, non-hazardous wood waste, green waste, landscape waste, and other sources of waste products of organic origin. This includes byproducts from gardening, agriculture, forestry, timber industry, food processing industries, and similar sources, which have garnered growing interest as potential starting materials for the cellulose production for various industrial applications.

[0039] While cellulose can be a major ingredient of pesticide formulations, the pesticide formulations can also include lignin, hemicellulose, holocellulose, proteins, and fatty acids. The specific composition of lignin depends on the feedstock used. If softwood is utilized, lignin includes coniferyl alcohol; for hardwood, lignin includes coniferyl alcohol and sinapyl alcohol; and grass lignin is exclusively composed of three monomers: coniferyl, sinapyl, and p-coumaryl alcohol. Hemicellulose includes xyloglucans, xylans, mannans, glucomannans, and beta- (l->3,l->4)-glucans. Additionally, cellulose may include proteins and their derivatives, such as amino acids and fatty acids depending on the used feedstocks. During NOPs, if cellulose is mixed with lignin, the cellulose can refer to lignin cellulose macro- / micro / -nanofiber or LCNF.1.1 Example Embodiment 1

[0040] In an example embodiment, large-scale production of charged cellulosic fibrils, e.g., nitro-oxidized cellulose nanofibers (NOCNF), was carried out using jute fibers as the raw material. The jute feedstock, having an initial moisture content of approximately 13%, was processed in a closed 2000-gallon reactor system. Approximately 469 pounds of size-reduced jute fibers (average length of ~80 mm) were combined with about 6123 pounds of 50% nitricacid solution. The reaction mixture was maintained under continuous agitation at 120 rpm and at a controlled temperature of 50°C.

[0041] Aliquots of the reaction mixture were collected at predetermined time intervals of 4 hours, 5 hours, 6 hours, and 7 hours to assess the extent of oxidation. At the completion of each reaction interval, the oxidized cellulose fibers were separated from the reaction liquor using a Nutsche filter unit (84-inch diameter, 34-inch height). The recovered solids were subsequently washed with excess deionized water until the pH of the suspension reached approximately 2.5-3.0.

[0042] The degree of oxidation, represented by the concentration of carboxyl functional groups (-COOH) introduced onto the cellulose backbone, was determined using potentiometric titration. The NOCNFs can have a degree of oxidation between about 0.8-about 3.0 mmol - COOH / g. Depending on the reaction time and conditions, the carboxyl content was found to be in the range of about 1.2 mmol / g to about 1.8 mmol / g of cellulose, within manufacturing and / or measurement tolerances.2. Pesticide Formulation Composition

[0043] The pesticide formulation can be made by dispersing charged cellulosic fibrils in water at about 0.01 wt%-about 5 wt%, or at about 0.05 wt%-about 1 wt%, within manufacturing and / or measurement tolerances, adding pesticide active ingredients in selected form, adjusting pH to about 3-about 11, or to about 5-about 11, to optimize solubility and ionic interactions. Surfactant(s) or oil(s) can be added to tune dispersion and spreading. The pesticide formulation can be homogenized via blending, high-shear mixing, or ultrasonication.

[0044] Charged cellulosic fibrils, such as charged NOCNF fibrils, can be incorporated into an aqueous formulation containing an pesticide active ingredient, such as the glyphosate and 2,4- D-based herbicides. The pesticide active ingredient can include a herbicide (e.g., glyphosate, 2,4-D, dicamba, atrazine, triclopyr, glufosinate ammonium, paraquat, metolachlor, acetochlor, pendimethalin, sulfentrazone, and derivatives), insecticides (e.g., imidacloprid, clothianidin, thiamethoxam, lambda-cyhalothrin, deltamethrin, permethrin, chlorpyrifos, malathion, fipronil, spinosad, abamectin, etc.), or fungicides (e.g., azoxystrobin, pyraclostrobin, mancozeb, propiconazole, difenoconazole, tebuconazole, captan, thiophanate-methyl, metalaxyl, sulfur,copper hydroxide, etc.). The pesticide active ingredients can be used in acid, salt, ester, amine, or agriculturally acceptable derivative forms.

[0045] The charged cellulosic fibrils, e.g., charged NOCNF fibrils, are dispersed in the formulation at a concentration sufficient to stabilize and suspend the active ingredient. The amount of charged cellulosic fibrils used will depend on the specific application and desired properties of the final product.

[0046] The formulation can also include additional components, such as surfactants, binders, or other additives, to enhance performance, though the primary focus is on reducing or eliminating toxic solvents. Additional ingredients can include one or more of selected from the group of surfactants (e.g., non-ionic, cationic, anionic, amphiphilic, etc. with specific example of Triton X-100, Tween, Span, alkyl polyglucosides, oils (e.g., methylated seed oils, vegetable oils, mineral oils), adjuvants, binders, antifoaming agents, or viscosity modifiers.

[0047] The pesticide formulation can be deliverable as a sprayable liquid, a suspension concentrate (SC), an emulsifiable concentrate (EC), an oil dispersion (OD), a capsule suspension (CS), or a wettable powder (WP) and can be used in foliar spraying, soil treatment, seed coating, and post-harvest protection. The pesticide formulations can be used to provide improved herbicidal, insecticidal, and fungicidal formulations with enhanced solubility, stability, adhesion, rain fastness, drift control, and controlled release; long-lasting weed, pest, and fungal control; enhanced leaf-surface retention, reduced runoff, and extended activity; and wood preservation, coatings, and post-harvest pathogen control.2.1 Example Embodiment 2

[0048] In this example embodiment, about 1.0 g of 2,4-D free acid (FA) was mixed with an amount of 1 wt% CNF aqueous suspension using a blender for a few minutes which creates a visually homogeneous slurry (termed 2,4-D-CNF mix) as shown in Figs. 1A and IB. The photographs in Figs. 1A and 1G show the dispersion of 2,4-dichlorophenoxyacetic acid (2,4-D) in a 1.0 wt% cellulose nanofiber (CNF) aqueous suspension, illustrating the mixing behavior.2.2 Example Embodiment s

[0049] To further improve the molecular dispersion of 2,4-D free acid (FA), Triton X-100, a non-ionic surfactant was added in the CNF suspension to reduce the interfacial tensionbetween the hydrophobic active ingredient (in this case 2,4-D) and aqueous medium. Figs. 2A and 2B show representative formulations of free acid (FA) form of 2,4-dichlorophenoxyacetic acid (2,4-D) and glyphosate and their salts form (2,4-D dimethyl amine (DMA) and glyphosate isopropylamine (IPA), prepared with varying concentrations of cellulose nanofibers (CNF) and optional surfactant additives. The photographs of Figs. 2Aand 2B show glyphosate, glyphosate isopropylamine salt (IPA), 2,4-D, and 2,4-D dimethyl amine (DMA) salt-based formulations prepared by mixing with appropriate concentrations (wt %) of cellulose nanofibers (CNF) and / or non-ionic surfactant (Triton X-100).

[0050] Glyphosate in the form of isopropylamine (IPA) salt is highly water-soluble and forms a clear aqueous solution in the presence of 0.1 wt% CNF ((a) of Figs. 2A and 2B). In contrast, glyphosate in its acid form exhibits only limited solubility in water; however, incorporation of a 0.1 wt% CNF suspension facilitates its dispersion and solubilization ((b) of Figs. 2A and 2B). The adjustment of the pH level to approximately 5-approximately 6 using 1 M NaOH further promotes dissolution, resulting in a clear solution.

[0051] For 2,4-D, the acid form demonstrates poor solubility in water but when a 0.1 wt% CNF suspension is mixed with 2,4-D, a turbid dispersion is observed, with undissolved solid particles remaining visibly suspended ((c) of Figs. 2A and 2B). The addition of a non-ionic surfactant such as Triton X-100 induces turbidity and controls dispersion, though it does not overcome the fundamental solubility limitation of the acid form ((d) of Fig. 2A and 2B).Surfactant incorporation also results in foam generation. In contrast, the dimethylammonium (DMA) salt form of 2,4-D is readily miscible in water and in 0.1 wt% CNF suspension, producing a clear solution without the need for additional surfactants ((e) of Figs. 2A and 2B).2.3 Example Embodiment 4

[0052] Surprisingly, it was observed that adjustment of the pH of a cellulose nanofiber (CNF) suspension containing 2,4-dichlorophenoxyacetic acid (2,4-D FA), significantly enhanced solubility. As shown in Figs. 3A and 3B, the mixture of 2,4-D FA with 0.1 wt% CNF produced a turbid suspension immediately after mixing (left side). However, upon gradual adjustment of the pH to approximately 11, the mixture transitioned into a clear solution (right side). Figs. 3A and 3B show photographs of the effect of pH adjustment on the dispersibility of 2,4-dichlorophenoxyacetic acid (2,4-D) in a cellulose nanofiber (CNF) suspension, showing turbid suspension immediately after mixing (left side) and showing a clear solution after pH adjustment to 11 (right side). This observation indicates that increasing the pH promotes ionization of 2,4-D FA, thereby facilitating its solubilization in the presence of CNF.

[0053] Collectively, these examples demonstrate that CNF can improve the dispersibility and stability of pesticide active ingredients in aqueous formulations. For highly soluble salt forms (e.g., glyphosate IPA, 2,4-D DMA), CNF acts as a stabilizing medium, while for poorly soluble acid forms (e.g., glyphosate acid, 2,4-D acid), CNF in combination with pH adjustment or surfactant addition enhances suspension quality and facilitates more uniform dispersion.2.4 Example Embodiment 5

[0054] The viscosity of varying CNF and pesticide formulations is studied as shown in Figs. 4 and 5. The graph of Fig. 4 shows the viscosity of 0.1 wt% CNF, 0.1 wt% CNF mixed with 0.16 wt% glyphosate, and 0.16 wt% glyphosate in water with varied shear rate. The graph of Fig. 5 shows variation of the viscosity of 0.1 wt% CNF, 0.1 wt% CNF mixed with 0.21 wt% glyphosate IPA, and 0.21 wt% glyphosate IPA in water with varied shear rate. Overall, the prepared formulations' viscosity is increased substantially or dramatically with the addition of CNF. CNF containing herbicide formulations showed shear thinning behavior where the viscosity decreased with the increasing shear rate. In contrast, the viscosity of aqueous herbicide solutions remained relatively low, and it showed minimal dependence on the shear rate. Due to entangled fiber networks CNF, at lower shear rates CNF-herbicide suspension resists flow while with increase in shear rate, the fibers align, and the network starts to collapse resulting in a drop of the viscosity. The of viscosity the pesticide formulations at shear rates below 100 s-1can be at least 5X greater than that of a fibril-free pesticide formulation, while sprayability of the pesticide formulation is maintained at shear rates above 500 s-1.

[0055] CNF-pesticide formulations show a much higher viscosity than that of the aqueous pesticide solutions at lower shear rates. This demonstrates the rheology modifying behavior of CNF. Even at a very low CNF weight percentage (e.g., 0.1 wt%), CNF boosts the viscosity of the pesticide formulation and imparts the shear thinning behavior.

[0056] This viscosity modification is beneficial when it comes to the application of pesticides. Higher viscosity at low shear rates can suppress the sedimentation of the active ingredients and it reduces the drifting of the pesticides while spraying. It also ensures that the pesticides formulation still sprays easily through the nozzle at higher shear rates due to its shear thinning behavior. The increase in the viscosity of the pesticide formulation tend to produce larger droplets which are less prone to drift. Thus, CNF act as a carrier media as well as a drift retardant.

[0057] CNF also serves as a thickening agent, which gives the watery pesticide solutions a pseudo plastic behavior, thus improving the retention and deposition of the active ingredients on target surfaces. Although the pesticide itself shows a minor contribution to viscosity, it enhances the network strength of the system in the presence of CNF. This is depicted by the synergistic increase in viscosity of the pesticide-CNF mixture compared to CNF alone. This is predominant at low shear rates. At shear rates closer to 1000 s’1, CNF-glyphosate mixture has a slightly higher viscosity than that of CNF itself and it is within a similar order of magnitude with the pure pesticide solution. This may be because at high shear rates, the network collapses and the fibers are aligned with the flow. But even at higher shear rates, CNF-pesticide mixtures have a higher viscosity than pure pesticide solutions. Introduction of counter ions that come along with the salt forms of glyphosate (isopropyl amine in the case of glyphosate IPA and sodium ions from NaOH in the case of glyphosate) into oxidized CNF induce crosslinking, which have ultimately resulted in the increase in the viscosity of the CNF-pesticide mixtures.

[0058] In summary, in addition to acting as a carrier medium for pesticide molecules, CNF acts as a viscosity modifier, drift retardant, and also improves the spray ability and formulation stability of their active ingredients.2.6 Example Embodiment 6

[0059] To evaluate wetting performance, cellulose nanofiber (CNF)-pesticide formulations were prepared and analyzed on polydimethylsiloxane (PDMS) sheets, selected as a model substrate to mimic the hydrophobic nature of plant leaf surfaces.

[0060] A CNF-glyphosate formulation was prepared by combining 0.1 wt% CNF with 0.16 wt% glyphosate acid. Due to the limited solubility of glyphosate in aqueous media, the pH ofthe mixture was adjusted to approximately 5-approximately 6 with 1 M NaOH to facilitate dissolution. A CNF-glyphosate isopropylamine (IPA) formulation was similarly prepared by mixing 0.1 wt% CNF with 0.21 wt% glyphosate IPA salt, which is inherently soluble in water and naturally exhibits a pH near 5-6. CNF-2,4-D DMA formulations were prepared by mixing 0.1 wt% CNF with 0.41 wt% 2,4-D dimethylammonium salt, while CNF-2,4-D acid formulations were prepared by mixing 0.1 wt% CNF with 0.34 wt% 2,4-D free acid. For the latter, pH adjustment with 1 M NaOH was necessary to enhance dissolution.

[0061] Table 1 below shows the surface tension values (y), and static contact angle values (0) of CNF, water and CNF-2,4 D, and different glyphosate-based formulations, where adding CNF shows significantly improved wetting behavior.

[0062] For example, the CNF mixed glyphosate IPA formulation (0.1 wt% CNF + 0.21 wt% glyphosate IPA) exhibited a reduced static contact angle on PDMS (87.0°-87.4°) compared to glyphosate IPA in water (95.7°-96.2°), corresponding to a reduction of approximately 8°-9°. This improvement coincided with a modest decrease in equilibrium surface tension from 72.8 mN-m"1(water) to 69.2 mN-m"1. Similarly, CNF + 2,4-D DMA (y - 64.46 mN-m"1) produced contact angles of 83.3°-84.1°, while CNF + 2,4-D acid (y - 56.50 mN-m"1) yielded a contact angle of 86.7° (0 = 86.7°).

[0063] Collectively, these results demonstrate that CNF-containing pesticides formulations consistently exhibit lower contact angles and reduce surface tension relative to water or pesticides-in-water controls. For example, the CNF can be controlled to provide a pesticide formulation with a surface tension in a range of about 30.0 mN / m-about 72.8 mN / m, within manufacturing and / or measurement tolerances. Such modifications to lower contact angles and to reduce surface tension can enhance spreading and adhesion on hydrophobic surfaces (e.g. plant leave's surface) while retaining sufficiently high surface tension to minimize drift during spraying. These findings indicate that CNF can serve as a multifunctional additive to adjust the balance between droplet retention and drift control in pesticide formulations.Table 1. Contact angle measurements of water, CNF suspension, and CNF-based pesticide formulations (glyphosate and 2,4-D) on PDMS substrates, demonstrating the effect of CNF incorporation on surface tension and wettability relative to hydrophobic surfaces.2.6 Example Embodiment 7

[0064] Figs. 6A and 6B show the droplet morphology of various pesticide formulations deposited on wild lettuce leaves, a representative weed surface. Figs. 6A and 6B are photographs showing droplet morphology of pesticide formulations on wild lettuce leaves, with (a) showing commercial 2,4-D DMA solution with a flattened droplet with broad spreading, (b) showing 2,4-D DMA with 0.5 wt% CNF a more rounded droplet and reduced spreading, and (c)— (h) showing additional formulations of 2,4-D free acid (FA), 2,4-D IPA, and glyphosate free acid (FA) with 0.25-0.5 wt% CNF with heavier, less flattened droplets with improved adhesion contact.

[0065] The commercial 2,4-dimethylammonium (DMA) salt solution of 2,4-D produced a flattened droplet with broad surface spreading ((a) of Figs. 6A and 6B). In contrast, incorporation of 0.5 wt% cellulose nanofibers (CNFs) resulted in a more rounded droplet with reduced spreading, indicating CNF-mediated modulation of surface tension and leaf contact ((b) of Figs. 6A and 6B) depending on CNF viscosity. Similarly, formulations of 2,4-D in its free acid(FA) form, its isopropylamine (IPA) salt, and glyphosate in its FA form exhibited improved droplet morphology and surface contact when combined with CNF ((c)— (h ) of Figs. 6A and 6B). At CNF concentrations of 0.25 wt% and 0.5 wt%, the droplets demonstrated heavier, less flattened profiles with well-tuned adhesion, which can be further improved by adding surfactant or oils or deceasing the CNF concentration.3. Mechanism of Action

[0066] The charged cellulosic fibrils interact with the active ingredient through electrostatic forces, hydrogen bonding, or van der Waals forces, depending on the specific chemical nature of the active ingredient. This interaction prevents the active ingredient from precipitating out of the formulation, thereby maintaining a homogeneous mixture.

[0067] The charged cellulosic fibrils may also form a network structure within the formulation, providing additional physical stabilization and preventing aggregation or sedimentation of the active ingredient.4. Applications

[0068] Example embodiments of the present invention can be used to stabilize esters, salts, or other forms of active ingredients in pesticide and herbicide formulations. This includes, but is not limited to, the stabilization of triclopyr esters, glyphosate, atrazine, 2,4-D (2,4- Dichlorophenoxyacetic acid), dicamba, glufosinate ammonium, metolachlor, acetochlor, pendimethalin, paraquat, sulfentrazone, etc. in aqueous formulations.

[0069] The charged cellulosic fibrils can be used to coat or encapsulate nutrients in fertilizers, providing controlled release and reducing nutrient loss.

[0070] In industrial applications, the charged cellulosic fibrils can stabilize pigments, resins, or other active ingredients in coatings and adhesives, improving performance while reducing the need for organic solvents.4.1 Example Embodiment s

[0071] Figs. 7A and 7B show spray tests of a formulation comprising 2 wt% cellulose nanofibers (CNF) blended with 1 wt% 2,4-dichlorophenoxyacetic acid (2,4-D FA) applied to sacrificial plant leaves. As shown in Figs. 7A and 7B, the CNF-containing formulation produced a smooth, continuous, and thin coating layer on the leaf surface, thereby increasing surface contact and adhesion of the suspension. The hydrophilic nature of CNF facilitates waterretention within the deposited layer, which can prolong moisture availability and enhance diffusivity of the active ingredient into plant tissues over time. This property addresses a critical limitation of conventional pesticide formulations, which typically dry within a few hours after application, thereby reducing uptake efficiency and overall bioavailability of the active ingredient.4.2 Example Embodiment 9

[0072] Phytotoxicity evaluation of different CNF and 2,4-D-based formulations on tomato plants at Day 0 (Panel A) and Day 14 (Panel B) is shown in Figs. 8A and 8B. In Figs. 8A and 8B, the combination of CNF (0.5 wt%) with 2,4-D free acid (FA, 0.5 wt%) produced a faster and more pronounced phytotoxic effect on tomato plants compared to other 2,4-D formulations, suggesting enhanced delivery and / or bioavailability. In contrast, plants treated with CNF alone, as well as untreated control plants, remained healthy and survived, whereas all 2,4-D-based formulations caused visible phytotoxic effects.4.3 Example Embodiment 10

[0073] Figs. 9A and 9B show the phytotoxicity evaluation of CNF and glyphosate-based formulations on tomato plants at Day 0 (Panel A) and Day 14 (Panel B). The combination of CNF (0.5 wt%) with glyphosate free acid (FA, 0.5 wt%) resulted in a more rapid and pronounced phytotoxic effect on tomato plants, indicating improved delivery and / or bioavailability. Plants treated with CNF alone, as well as untreated controls, remained viable and healthy, confirming that the observed effects were attributable to the active ingredient. The combination of CNF (0.5 wt%) with glyphosate free acid (0.5 wt%) seemingly produced a stronger and faster phytotoxic response compared to formulations containing CNF (0.25 wt%) with glyphosate free acid (0.5 wt%). This dose-dependent effect demonstrates that higher CNF loading enhances the delivery efficiency and activity of glyphosate, providing an unexpected advantage over conventional formulations.4.4 Example Embodiment 11

[0074] Phytotoxicity tests were conducted on grasses to evaluate the performance of cellulose nanofiber (CNF)-based glyphosate formulations, as shown in Figs. 10A and 10B. The top panels ((a)-(c)) show plants at 45 hours after spraying, while the bottom panels ((d)— (f)) show the same plants after 14 days of observation.

[0075] At 45 hours, visible phytotoxic effects were limited, with only moderate changes in leaf coloration. However, by Day 14, pronounced differences were observed among the formulations. The formulation comprising 0.50 wt% CNF with 0.50 wt% glyphosate free acid (FA) exhibited foliage that remained partially green, intermixed with orange-brown regions, suggesting a slower progression of phytotoxic symptoms and a degree of retained leaf vitality. In contrast, the formulation containing 0.25 wt% CNF with 0.50 wt% glyphosate FA produced more faded, straw-colored leaves, with an overall drier appearance and visibly reduced plant density.

[0076] These results indicate that higher CNF loading (0.50 wt%) in combination with glyphosate FA may impart moderated phytotoxic effects, leading to less apparent plant stress relative to lower CNF loading (0.25 wt%). The observations suggest that CNF concentration can modulate the bioavailability and uptake dynamics of glyphosate FA, potentially providing a tunable parameter for optimizing herbicidal efficacy and persistence.5. Advantages

[0077] Example embodiments of the present invention can provide a safer, more environmentally friendly alternative to traditional solvent-based formulations.

[0078] By using charged cellulosic fibrils, the need for toxic solvents can be minimized or eliminated, reducing environmental impact and health risks associated with exposure to these chemicals.

[0079] The use of NOPs or other suitable processes to produce charged cellulosic fibrils can ensure that the fibrils have the necessary functional groups for effective stabilization, making the process of example embodiments of the present invention efficient and scalable.

[0080] It should be understood that the foregoing description is only illustrative of the present invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the present invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications, and variances that fall within the scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A pesticide formulation comprising: a pesticide active ingredient; nitro-oxidized cellulose nanofibers (NOCNFs); and water.

2. The pesticide formulation of claim 1, wherein the pesticide active ingredient includes one or more selected from the group including herbicides, insecticides, or fungicides.

3. The pesticide formulation of claim 1 or 2, wherein the pesticide active ingredient includes one or more selected from the group including glyphosate, 2,4-D, dicamba, atrazine, triclopyr, glufosinate ammonium, paraquat, metolachlor, acetochlor, pendimethalin, sulfentrazone, imidacloprid, clothianidin, thiamethoxam, lambda-cyhalothrin, deltamethrin, permethrin, chlorpyrifos, malathion, fipronil, spinosad, abamectin, azoxystrobin, pyraclostrobin, mancozeb, propiconazole, difenoconazole, tebuconazole, captan, thiophanate- methyl, metalaxyl, sulfur, copper hydroxide, a derivate thereof, or a combination thereof.

4. The pesticide formulation of claim 1 or 2, wherein the pesticide active ingredient is in an acid, a salt, an ester, an amine, or a derivative form.

5. The pesticide formulation of one of claims 1-4, wherein the NOCNFs have a degree of oxidation between about 0.8-about 3.0 mmol -COOH / g.

6. The pesticide formulation of one of claims 1-5, wherein the NOCNFs include a counterion selected from the group including sodium, potassium, ammonium, or a combination thereof.

7. The pesticide formulation of one of claims 1-6, wherein the NOCNFs are included in a range of about 0.01 wt%-about 5 wt%.

8. The pesticide formulation of one of claims 1-6, wherein the NOCNFs are included in a range of about 0.05 wt%-about 1 wt%.

9. The pesticide formulation of one of claims 1-8, further including a surfactant, an oil, an adjuvant, a binder, an antifoaming agent, or a viscosity modifier.

10. The pesticide formulation of one of claims 1-9, further including lignin, hemicellulose, holocellulose, protein, or a fatty acid.

11. The pesticide formulation of one of claims 1-10, wherein the pesticide formulation has a surface tension in a range of about 30.0 mN / m-about 72.8 mN / m.

12. The pesticide formulation of one of claims 1-11, wherein a viscosity at shear rates below 100 s’1of the pesticide formulation is at least 5X greater than that of a fibril-free pesticide formulation, while sprayability of the pesticide formulation is maintained at shear rates above 500 s-1.

13. A method of preparing a pesticide formulation comprising: providing nitro-oxidized cellulose nanofibers (NOCNFs); and mixing the NOCNFs and a pesticide active ingredient in water.

14. The method of claim 13, further comprising adjusting pH to be between about 3- about 11.

15. The method of claim 13 or 14, wherein the NOCNFs are provided by producing charged cellulosic fibrils from biomass feedstock by a nitro-oxidation process.

16. The method of one of claims 13-15, wherein the pesticide active ingredient includes one or more selected from the group including herbicides, insecticides, or fungicides.

17. The method of one of claims 13-16, wherein the pesticide active ingredient includes one or more selected from the group including glyphosate, 2,4-D, dicamba, atrazine, triclopyr, glufosinate ammonium, paraquat, metolachlor, acetochlor, pendimethalin, sulfentrazone, imidacloprid, clothianidin, thiamethoxam, lambda-cyhalothrin, deltamethrin, permethrin, chlorpyrifos, malathion, fipronil, spinosad, abamectin, azoxystrobin, pyraclostrobin, mancozeb, propiconazole, difenoconazole, tebuconazole, captan, thiophanate-methyl, metalaxyl, sulfur, copper hydroxide, a derivate thereof, or a combination thereof.

18. The method of one of claims 13-16, wherein the pesticide active ingredient is in an acid, a salt, an ester, an amine, or a derivative form.

19. The method of one of claims 13-18, wherein the NOCNFs have a degree of oxidation between about 0.8-about 3.0 mmol -COOH / g.

20. The method of one of claims 13-19, wherein the NOCNFs include a counterion selected from the group including sodium, potassium, ammonium, or a combination thereof.

21. The method of one of claims 13-20, wherein the NOCNFs are included in a range of about 0.01 wt%-about 5 wt%.

22. The method of one of claims 13-20, wherein the NOCNFs are included in a range of about 0.05 wt%-about 1 wt%.

23. The method of one of claims 13-22, further comprising adding a surfactant, an oil, an adjuvant, a binder, an antifoaming agent, or a viscosity modifier.

24. The method of one of claims 13-23, wherein the pesticide formulation includes lignin, hemicellulose, holocellulose, protein, or a fatty acid.

25. The method of one of claims 13-24, wherein the pesticide formulation has a surface tension in a range of about 30.0 mN / m-about 72.8 mN / m.

26. The method of one of claims 13-25, wherein a viscosity at shear rates below 100 s-1of the pesticide formulation is at least 5X greater than that of a fibril-free pesticide formulation, while sprayability of the pesticide formulation is maintained at shear rates above 500 s-1.

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