Nanocellulose dispersion concentrate and masterbatch, methods for producing and using the same, and nanocellulose-containing composites

Abstract

The disclosed technology provides improved compositions and methods for dispersing and drying nanocellulose for polymer composites and other systems. Some variations provide nanocellulose dispersion concentrates comprising nanocellulose and a dispersing / desiccant selected to be compatible with the nanocellulose and nanocellulose-containing composite product, where the dispersing / desiccant is selected from the group consisting of wax, polyolefin, olefin-maleic anhydride copolymer, olefin-acrylic acid copolymer, polyol, fatty acid, fatty alcohol, polyol glyceride ester, polydimethylsiloxane, polydimethylsiloxane alkyl ester, polyacrylamide, starch, cellulose derivatives, particulates, and combinations or reaction products thereof, and the nanocellulose dispersion concentrate is in solid (e.g., powder) or liquid form. Other variations provide nanocellulose dispersion masterbatches (e.g., pellets) comprising the nanocellulose dispersion concentrate and a carrier material. Other variations provide nanocellulose-containing composites comprising the nanocellulose dispersion masterbatches or concentrates and a matrix material. Methods for making and using the disclosed compositions are described.

Description

Technical Field

[0001] Priority Data This international patent application claims priority to U.S. Provisional Patent Application No. 62 / 787,462, filed on January 2, 2019, which is incorporated herein by reference.

[0002] Field The present invention generally relates to compositions and methods for dispersing nanocellulose in polymers and other systems.

Background Art

[0003] Background Nanocellulose has attracted attention as a nanostructured material. Since nanocellulose is obtained from cellulose, a natural resource that is the most abundant polymer on earth, it is characterized by biodegradability and environmental sustainability. Furthermore, nanocellulose offers great technical potential to improve the mechanical strength and other properties of composites, regardless of its social and environmental sustainability. Nanocellulose is composed of parallel linear polysaccharide molecules. Nanocellulose has attractive physicochemical properties such as extremely high rigidity and strength, along with its abundance and sustainability.

[0004] Nanocellulose has been developed for use in a variety of applications such as polymer reinforcements, antibacterial films, biodegradable food packaging, printing paper, pigments and inks, paper and board packaging, barrier films, adhesives, biocomposites, wound healing, pharmaceuticals and drug delivery, textiles, water-soluble polymers, construction materials, recyclable interior and structural components for the transportation industry, rheology modifiers, low-calorie food additives, cosmetic thickeners, binders for pharmaceutical tablets, bioactive paper, pickering stabilizers for emulsions and particle-stabilized foams, paint formulations, films for optical switching, and detergents.

[0005] However, significant technical challenges remain associated with the widespread use of nanocellulose. In particular, removing water from a nanocellulose suspension while maintaining nanoscale dimensions is very difficult. In most cases, due to its hydrophilicity and tendency to aggregate during drying, nanocellulose particles are processed as an aqueous suspension. There is an industrial need to develop robust dispersion and drying processes that can maintain nanoscale dimensions for materials applications where a dry form is required. Also, a drier form of nanocellulose reduces the high transportation costs of dilute aqueous suspensions and increases the number of end uses where there is a limit to the amount of water that can be added to the product.

[0006] In the case of both cellulose nanocrystals and cellulose nanofibrils (or microfibrils), non-aqueous polymers and other systems typically require a dry form of nanocellulose for incorporation, so the dispersibility of nanocellulose in these systems remains a problem. Nanocellulose has a tendency to irreversibly self-bond during drying, resulting in large aggregates of nanocellulose. Large aggregates often interfere with, or even destroy, the benefits of the intended properties for the polymer composites or other systems into which the nanocellulose particles are introduced. For example, nanocellulose particles well-dispersed in a polymer can bring about a significant enhancement of mechanical strength. However, when nanocellulose aggregates, there may be no enhancement of mechanical strength, or it may even deteriorate, and large aggregates can result in stress concentrators that can cause premature failure of polymer components.

[0007] Regarding the improvement of the dispersion of nanocellulose in non-aqueous products, various drying approaches have been attempted. These approaches typically require extreme means that can prove difficult to scale up to commercial quantities and are thus uneconomical. Generally, these methods are based on the freeze-drying (lyophilization) of nanocellulose, which is an established laboratory method for preventing irreversible interparticle binding of nanocellulose. Freeze-drying is not economical or scalable for the commercial production of nanocellulose.

[0008] For virtually all non-aqueous applications in which nanocellulose is used, the improvement of its dispersion and thus the usefulness and benefits of these applications represent a major obstacle to the realization of nanocellulose. Therefore, it has become important to improve the dispersion of nanocellulose using an economical method that enables high-level dispersion of nanocellulose in polymers and other systems. Economical methods typically require a dry composition containing nanocellulose. The dry form of nanocellulose is particularly important in the field of thermoplastic resin processing such as extrusion and injection molding where a heat-melting process is induced. In the heat-melting process with non-polar thermoplastic resins, water is disadvantageous for satisfactory processing. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In view of the above-mentioned needs in the art, there is a strong need for improved compositions and methods for the dispersion and drying of nanocellulose for polymer composites and other systems other than polymers. MEANS FOR SOLVING THE PROBLEMS

[0010] SUMMARY Some variations of the present invention are (a) from about 5 wt% to about 90 wt% of nanocellulose, and (b) from about 5 wt% to about 95 wt% of a dispersion / drying agent selected to be compatible with the nanocellulose Provided is a nanocellulose dispersion concentrate comprising, wherein the dispersion / drying agent is selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and the nanocellulose dispersion concentrate is in solid or liquid form.

[0011] In some embodiments, the nanocellulose is present at a concentration of about 10 wt% to about 70 wt%, and the dispersion / drying agent is present at a concentration of about 5 wt% to about 50 wt%. In some embodiments, the weight ratio of nanocellulose to dispersion / drying agent is selected from about 0.5 to about 2. The nanocellulose dispersion concentrate may consist essentially of nanocellulose and the dispersion / drying agent, i.e., no other functional components may be present.

[0012] The nanocellulose may include cellulose nanocrystals, cellulose nanofibrils, microfibrillated cellulose, or combinations thereof. In some embodiments, the nanocellulose includes lignin-containing nanocellulose, such as lignin-coated nanocellulose.

[0013] In some embodiments, the dispersion / drying agent is a functionalized polyalkylene wax functionalized to be compatible with the nanocellulose. For example, the functionalized polyalkylene wax can be a functionalized polyethylene wax, a functionalized polypropylene wax, a functionalized polybutylene wax, or combinations thereof. In certain embodiments, the dispersion / drying agent is a low molecular weight oligomer or polymer of ethylene or functionalized ethylene having a number average degree of polymerization of 2 to 1000, such as 5 to 500.

[0014] In some embodiments, the dispersant / dryer is a copolymer of (a) one or more C2-C4 olefins and (b) maleic anhydride.

[0015] In some embodiments, the dispersant / dryer is a copolymer of (a) one or more C2-C4 olefins and (b) acrylic acid.

[0016] In some embodiments, the dispersant / dryer comprises a polyol selected from ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerol, butylene glycol, polybutylene glycol, or combinations thereof, wherein the polyol is optionally esterified with a fatty acid.

[0017] In some embodiments, the dispersant / dryer comprises an alkyl ester polydimethylsiloxane emulsion.

[0018] In some embodiments, the dispersant / dryer comprises cationic starch, amphoteric starch, thermoplastic starch, or combinations thereof.

[0019] In some embodiments, the dispersant / dryer optionally comprises fine particles having a surface treatment such as silylation of glass fibers to provide surface charge and / or improve interfacial adhesion. The fine particles can be selected from the group consisting of clay, nanoclay, talc, wollastonite, calcium carbonate (e.g., precipitated calcium carbonate), silica, mica, kaolin, nickel, glass fibers, bentonite, biotite, illite, kaolin, vermiculite, zeolite, carbon fibers, carbon nanotubes, graphene, or combinations thereof. In certain embodiments, the dispersant / dryer comprises at least one fatty acid and at least one fine particle.

[0020] The nanocellulose dispersion concentrate may further comprise a liquid solvent such as a solvent selected from the group consisting of water, C1-C8 alcohols, C2-C8 polyols, and combinations thereof.

[0021] The nanocellulose dispersion concentrate may further contain one or more elastomers (e.g., natural rubber or synthetic rubber) at a concentration of, for example, about 0.1 wt% to about 50 wt%.

[0022] Other variations of the present invention are (a) about 1 wt% to about 75 wt% of nanocellulose, and (b) about 1 wt% to about 89 wt% of a dispersion / drying agent selected to be compatible with the nanocellulose, and (c) about 10 wt% to about 98 wt% of a carrier material (e.g., a carrier polymer) different from the nanocellulose and the dispersion / drying agent to provide a nanocellulose dispersion masterbatch, wherein the dispersion / drying agent is selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and the nanocellulose dispersion masterbatch is in solid form or liquid form.

[0023] In some masterbatch embodiments, the nanocellulose is present at a concentration of about 10 wt% to about 50 wt%, and the dispersion / drying agent is present at a concentration of about 5 wt% to about 75 wt%. In some masterbatch embodiments, the weight ratio of nanocellulose to dispersion / drying agent is selected from about 0.5 to about 2. The nanocellulose dispersion masterbatch may consist essentially of nanocellulose, a dispersion / drying agent, and a carrier material.

[0024] In some masterbatch embodiments, the nanocellulose comprises cellulose nanocrystals, cellulose nanofibrils, microfibrillated cellulose, or combinations thereof.

[0025] In some masterbatch embodiments, the nanocellulose includes lignin-containing nanocellulose, such as lignin-coated nanocellulose.

[0026] In some masterbatch embodiments, the dispersant / drying agent is a functionalized polyalkylene wax functionalized to be compatible with nanocellulose. For example, the functionalized polyalkylene wax can be a functionalized polyethylene wax, a functionalized polypropylene wax, a functionalized polybutylene wax, or a combination thereof. In certain masterbatch embodiments, the dispersant / drying agent is a low molecular weight oligomer or polymer of ethylene or functionalized ethylene having a number average degree of polymerization of 2 to 1000.

[0027] In some masterbatch embodiments, the dispersant / drying agent is a copolymer of (a) one or more C2-C4 olefins and (b) maleic anhydride.

[0028] In some masterbatch embodiments, the dispersant / drying agent is a copolymer of (a) one or more C2-C4 olefins and (b) acrylic acid.

[0029] In some masterbatch embodiments, the dispersant / drying agent includes a polyol selected from ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerol, butylene glycol, polybutylene glycol, or a combination thereof, where the polyol is optionally esterified with a fatty acid.

[0030] In some masterbatch embodiments, the dispersant / drying agent includes an alkyl ester polydimethylsiloxane emulsion.

[0031] In some masterbatch embodiments, the dispersant / drying agent includes cationic starch, amphoteric starch, thermoplastic starch, or a combination thereof.

[0032] In some masterbatch embodiments, the dispersant / dryer optionally includes fine particles having a surface treatment such as silylation of glass fibers to provide surface charge and / or improve interfacial adhesion. The fine particles can be selected from the group consisting of clay, nanoclay, talc, wollastonite, calcium carbonate (e.g., precipitated calcium carbonate), silica, mica, kaolin, nickel, glass fiber, bentonite, biotite, illite, kaolin, vermiculite, zeolite, carbon fiber, carbon nanotube, graphene, or combinations thereof. In certain masterbatch embodiments, the dispersant / dryer includes at least one fatty acid and at least one fine particle.

[0033] The dispersant / dryer can be selected to be compatible with the carrier material of the masterbatch.

[0034] The carrier material can be a carrier polymer or another type of material. When the carrier material is a polymer or includes a polymer, the polymer can be selected from the group consisting of polyolefin, polyol, polyamide, polylactic acid, polystyrene, polycarbonate, polyethylene terephthalate, and combinations thereof.

[0035] In a preferred embodiment of the nanocellulose dispersion masterbatch, the masterbatch is in solid powder form.

[0036] Another variation of the present invention provides a nanocellulose-polymer composite product, which (a) about 0.05 wt% to about 10 wt% of nanocellulose, and (b) A dispersing / drying agent of about 0.05 wt% to about 10 wt% selected to be compatible with nanocellulose and nanocellulose-polymer composite products, which is selected from the group consisting of wax, polyolefin, olefin-maleic anhydride copolymer, olefin-acrylic acid copolymer, polyol, fatty acid, fatty alcohol, polyol-glyceride ester, polydimethylsiloxane, polydimethylsiloxane-alkyl ester, polyacrylamide, starch, cellulose derivative, fine particles, and combinations or reaction products thereof, and (c) A carrier polymer of about 0.1 wt% to about 10 wt% selected to be compatible with nanocellulose and the dispersing / drying agent, and (d) About 50 wt% to about 99.8 wt% of a matrix polymer and comprising.

[0037] In some embodiments of the composite product, the nanocellulose is present at a concentration of about 0.1 wt% to about 5 wt% in the nanocellulose-polymer composite product. In some embodiments of the composite product, the weight ratio of nanocellulose to the dispersing / drying agent is selected from about 0.5 to about 2. The nanocellulose-polymer composite product may consist essentially of nanocellulose, the dispersing / drying agent, the carrier polymer, and the matrix polymer.

[0038] In some embodiments of the composite product, the nanocellulose comprises cellulose nanocrystals, cellulose nanofibers, microfibrillated cellulose, or combinations thereof.

[0039] In some embodiments of the composite product, the nanocellulose comprises lignin-containing nanocellulose, such as lignin-coated nanocellulose.

[0040] In some embodiments of the composite product, the dispersing / drying agent is a functionalized polyalkylene wax functionalized to be compatible with nanocellulose and optionally with the nanocellulose-polymer composite product. For example, the functionalized polyalkylene wax can be a functionalized polyethylene wax, a functionalized polypropylene wax, a functionalized polybutylene wax, or a combination thereof. In certain embodiments of the composite product, the dispersing / drying agent is a low molecular weight oligomer or polymer of ethylene or functionalized ethylene having a number average degree of polymerization of 2 to 1000.

[0041] In some embodiments of the composite product, the dispersing / drying agent is a copolymer of (a) one or more C2-C4 olefins and (b) maleic anhydride.

[0042] In some embodiments of the composite product, the dispersing / drying agent is a copolymer of (a) one or more C2-C4 olefins and (b) acrylic acid.

[0043] In some embodiments of the composite product, the dispersing / drying agent comprises a polyol selected from ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerol, butylene glycol, polybutylene glycol, or combinations thereof, wherein the polyol is optionally esterified with a fatty acid.

[0044] In some embodiments of the composite product, the dispersing / drying agent comprises an alkyl ester polydimethylsiloxane emulsion.

[0045] In some embodiments of the composite product, the dispersing / drying agent comprises cationic starch, amphoteric starch, thermoplastic starch, or combinations thereof.

[0046] In some embodiments of the composite product, the dispersant / dryer comprises fine particles having a surface treatment such as silylation of glass fibers to provide surface charge and / or improve interfacial adhesion. The fine particles can be selected from the group consisting of clay, nanoclay, talc, wollastonite, calcium carbonate (e.g., precipitated calcium carbonate), silica, mica, kaolin, nickel, glass fibers, bentonite, biotite, illite, kaolin, vermiculite, zeolite, carbon fibers, carbon nanotubes, graphene, or combinations thereof. In certain embodiments, the dispersant / dryer comprises at least one fatty acid and at least one fine particle.

[0047] In some embodiments of the composite product, the dispersant / dryer is selected to be compatible with the carrier polymer, the matrix polymer, or both.

[0048] The carrier polymer can be selected from the group consisting of polyolefin, polyol, polyamide, polylactic acid, polystyrene, polycarbonate, polyethylene terephthalate, and combinations thereof. The carrier polymer can be the same polymer as the matrix polymer. Alternatively, the carrier polymer can be a different polymer than the matrix polymer.

[0049] In various nanocellulose-polymer composite products, the matrix polymer is selected from the group consisting of polyolefin, polyol, polyester, polyamide, polylactic acid, polystyrene, polycarbonate, polyacrylate, polystyrene, styrenic rubber, polyurethane, polyurea, poly(amide-enamine), polyanhydride, polyhydroxyalkanoate, poly(alkenedicarboxylate), silicone, carbonaceous polymer, and combinations or copolymers thereof.

[0050] Yet another variation of the present invention provides a nanocellulose-polymer composite product, which is (a) from about 0.05 wt% to about 15 wt% of nanocellulose, and (b) A dispersing / drying agent of about 0.05 wt% to about 15 wt% selected to be compatible with nanocellulose and nanocellulose-polymer composite products, which is selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and (c) about 50 wt% to about 99.9 wt% of a matrix polymer and comprises.

[0051] In some embodiments, for example, when the nanocellulose dispersion concentrate is directly incorporated into the matrix polymer without going through a masterbatch, the carrier polymer does not exist.

[0052] In some embodiments of the composite product that does not contain a carrier polymer, the nanocellulose is present in the nanocellulose-polymer composite product at a concentration of about 0.1 wt% to about 5 wt%, for example, about 0.5 wt% to about 2 wt%. The nanocellulose-polymer composite product may essentially consist of nanocellulose, a dispersing / drying agent, and a matrix polymer. The options for the nanocellulose, the dispersing / drying agent, and the matrix polymer are the same as those summarized above for these components in the nanocellulose-polymer composite product containing a carrier polymer.

[0053] Another variation of the present invention provides a nanocellulose-containing composite product, which (a) about 0.05 wt% to about 10 wt% of nanocellulose, and (b) A dispersing / drying agent of about 0.05 wt% to about 10 wt%, selected to be compatible with nanocellulose and nanocellulose-containing composite products, which is selected from the group consisting of wax, polyolefin, olefin-maleic anhydride copolymer, olefin-acrylic acid copolymer, polyol, fatty acid, fatty alcohol, polyol-glyceride ester, polydimethylsiloxane, polydimethylsiloxane-alkyl ester, polyacrylamide, starch, cellulose derivative, fine particles, and combinations or reaction products thereof, and a dispersing / drying agent, (c) A carrier material of about 0.1 wt% to about 10 wt%, selected to be compatible with nanocellulose and the dispersing / drying agent, (d) About 50 wt% to about 99.8 wt% of a matrix material and comprising.

[0054] Still other variations of the present invention provide nanocellulose-containing composite products, which (a) About 0.05 wt% to about 15 wt% of nanocellulose, and (b) A dispersing / drying agent of about 0.05 wt% to about 15 wt%, selected to be compatible with nanocellulose and nanocellulose-containing composite products, which is selected from the group consisting of wax, polyolefin, olefin-maleic anhydride copolymer, olefin-acrylic acid copolymer, polyol, fatty acid, fatty alcohol, polyol-glyceride ester, polydimethylsiloxane, polydimethylsiloxane-alkyl ester, polyacrylamide, starch, cellulose derivative, fine particles, and combinations or reaction products thereof, and a dispersing / drying agent, (c) About 50 wt% to about 99.9 wt% of a matrix material and comprising.

[0055] Some variations provide a method for producing a nanocellulose dispersion concentrate (e.g., the concentrate disclosed above), the method comprising providing a nanocellulose gel comprising nanocellulose and water, and Selecting a dispersant / drying agent to be compatible with nanocellulose, wherein the dispersant / drying agent is selected from the group consisting of wax, polyolefin, olefin-maleic anhydride copolymer, olefin-acrylic acid copolymer, polyol, fatty acid, fatty alcohol, polyol-glyceride ester, polydimethylsiloxane, polydimethylsiloxane-alkyl ester, polyacrylamide, starch, cellulose derivative, fine particle, and combinations or reaction products thereof, Mixing the nanocellulose gel and the dispersant / drying agent, Removing at least a portion of the water during or after the mixing step to produce a nanocellulose dispersion concentrate, Optionally, grinding the nanocellulose dispersion concentrate to produce a powder, Recovering the nanocellulose dispersion concentrate in a solid form or a liquid form comprising.

[0056] In some embodiments, the step of removing at least a portion of the water includes high-shear mixing with heating to a temperature of at least 50 °C.

[0057] In some embodiments, the method further includes combining the nanocellulose dispersion concentrate with a carrier material to form a nanocellulose dispersion masterbatch. The carrier material can be, for example, a carrier polymer.

[0058] In some embodiments, the method further includes combining the nanocellulose dispersion masterbatch with a matrix material to form a nanocellulose-containing composite product.

[0059] The matrix material can be a matrix polymer. For example, the matrix polymer can be selected from the group consisting of polyolefins, polyols, polyesters, polyamides, polylactic acid, polystyrenes, polycarbonates, polyacrylates, polystyrenes, natural rubbers, synthetic rubbers, styrenic rubbers, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyhydroxyalkanoates, poly(alkenedicarboxylates), silicones, carbonaceous polymers, and combinations or copolymers thereof.

[0060] Alternatively or additionally, the matrix material can be a material other than a polymer, such as a material selected from the group consisting of paper, paperboard, fibers and wood composites (e.g., particle board and molded pulp products), emulsions, hydrogels, carbon, organic solids, inorganic solids, oils, organic liquids, inorganic liquids, cementitious materials, microparticles, ceramics, metals, metal alloys, glass, and combinations thereof.

[0061] The drying step (removing at least a portion of the water) to form the concentrate can be carried out at the same location or a different location as an optional step for manufacturing the masterbatch. Also, the drying step can be carried out at the same location or a different location as the step of combining the nanocellulose dispersion masterbatch or concentrate with the matrix material.

[0062] In some embodiments, the method further includes directly (without passing through the masterbatch) combining the nanocellulose dispersion concentrate with the matrix material to form a nanocellulose-containing composite product.

[0063] When the nanocellulose dispersion concentrate is added directly to the matrix material, the matrix material can be a matrix polymer such as a polymer selected from the group consisting of polyolefins, polyols, polyesters, polyamides, polylactic acid, polystyrene, polycarbonates, polyacrylates, polystyrene, styrenic rubbers, natural rubbers, synthetic rubbers, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyhydroxyalkanoates, poly(alkenedicarboxylates), silicones, carbonaceous polymers, and combinations or copolymers thereof.

[0064] Alternatively or additionally, the matrix material can be selected from the group consisting of paper, paperboard, fiber and wood composites, emulsions, hydrogels, carbon, organic solids, inorganic solids, oils, organic liquids, inorganic liquids, cementitious materials, particulates, ceramics, metals, metal alloys, glass, and combinations thereof.

[0065] Some variations provide a method for producing a nanocellulose dispersion masterbatch (e.g., the masterbatch disclosed above), the method comprising providing a nanocellulose gel comprising nanocellulose and water; selecting a dispersion / drying agent to be compatible with the nanocellulose, the dispersion / drying agent being selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, particulates, and combinations or reaction products thereof; mixing the nanocellulose gel and the dispersion / drying agent; removing at least a portion of the water during or after the mixing step to produce a nanocellulose dispersion concentrate; optionally, grinding the nanocellulose dispersion concentrate to produce a concentrate powder; During mixing the nanocellulose gel and the dispersion / drying agent, and / or during removing at least a part of water, and / or after removing at least a part of water (thereby generating a nanocellulose dispersion masterbatch), and / or during (if implemented) grinding the nanocellulose dispersion concentrate to generate a concentrate powder, and / or after (if implemented) grinding the nanocellulose dispersion concentrate to generate a concentrate powder, introducing a carrier polymer (or other carrier material) into the nanocellulose dispersion concentrate to generate a nanocellulose dispersion masterbatch, and Optionally, grinding the nanocellulose dispersion masterbatch to generate a masterbatch powder, and recovering the nanocellulose dispersion masterbatch, preferably in solid form, and comprise.

[0066] Some variations provide a method for manufacturing a nanocellulose-polymer composite product (e.g., the composite product disclosed above), the method comprising providing a nanocellulose gel comprising nanocellulose and water, and selecting a dispersion / drying agent to be compatible with the nanocellulose and the nanocellulose-polymer composite product, the dispersion / drying agent being selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and mixing the nanocellulose gel and the dispersion / drying agent, and removing at least a part of water during or after the mixing step to generate a nanocellulose dispersion concentrate, and Optionally, grinding the nanocellulose dispersion concentrate to generate a concentrate powder, and During mixing the nanocellulose gel and the dispersion / drying agent, and / or during removing at least a part of water, and / or after removing at least a part of water (thereby producing a nanocellulose dispersion masterbatch), and / or during (if carried out) grinding the nanocellulose dispersion concentrate to produce a concentrate powder, and / or after (if carried out) grinding the nanocellulose dispersion concentrate to produce a concentrate powder, introducing a carrier polymer into the nanocellulose dispersion concentrate to produce a nanocellulose dispersion masterbatch, and Optionally, grinding the nanocellulose dispersion masterbatch to produce a masterbatch powder, and Mixing the nanocellulose dispersion masterbatch with a matrix polymer and mechanically and / or thermally processing the combined material to produce a nanocellulose-polymer composite product, and Recovering the nanocellulose-polymer composite product and comprise.

[0067] Certain variations provide a method for manufacturing a nanocellulose-polymer composite product without using a carrier polymer, the method comprising providing a nanocellulose gel comprising nanocellulose and water, and selecting a dispersion / drying agent to be compatible with the nanocellulose and the nanocellulose-polymer composite product, the dispersion / drying agent being selected from the group consisting of wax, polyolefin, olefin-maleic anhydride copolymer, olefin-acrylic acid copolymer, polyol, fatty acid, fatty alcohol, polyol-glyceride ester, polydimethylsiloxane, polydimethylsiloxane-alkyl ester, polyacrylamide, starch, cellulose derivative, microparticle, and combinations or reaction products thereof, and mixing the nanocellulose gel and the dispersion / drying agent, and removing at least a part of water during or after the mixing step to produce a nanocellulose dispersion concentrate, and Optionally, grinding the nanocellulose dispersion concentrate to produce a concentrate powder, mixing the nanocellulose dispersion concentrate with a matrix polymer and mechanically and / or thermally processing the combined materials to produce a nanocellulose-polymer composite product, recovering the nanocellulose-polymer composite product and including.

Brief Description of the Drawings

[0068] Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0069] Detailed description of some embodiments This description enables those skilled in the art to make and use the present invention and describes some embodiments, adaptations, variations, alternatives, and uses of the present invention. These and other embodiments, features, and advantages of the present invention will become more apparent to those skilled in the art upon consideration of the following detailed description of the present invention in conjunction with any accompanying drawings.

[0070] As used in this specification and the claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" include plural referents. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All numbers and ranges of compositions based on percentages are, unless otherwise indicated, weight percentages. All ranges of numbers or conditions are meant to include any specific value contained within the range rounded to any appropriate decimal place.

[0071] Unless otherwise stated, all numbers representing parameters, reaction conditions, concentrations of components, etc. used in this specification and the claims should be understood to be modified in all cases by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and claims are approximations that may vary depending at least upon the particular analytical technique employed.

[0072] The term "comprising", which is synonymous with "including", "containing", or "characterized by", is inclusive or open-ended and does not exclude additional elements or method steps not recited. "Comprising" is a term of art used in claim terms and means that the named claim elements are essential, but that other claim elements may be added and still form a construct within the scope of that claim.

[0073] As used herein, the phrase "consisting of" excludes any element, step, or ingredient not specified in the claim. When the phrase "consisting of" (or a variation thereof) appears in a clause of the claim body rather than immediately following the preamble, it limits only the elements recited in that clause; other elements are not excluded from the claim as a whole. As used herein, the phrase "consisting essentially of" limits the scope of the claim to, Specified element or method step in addition to, Those that do not substantially affect the basic and novel features of the claimed subject matter as specified in Those that do not substantially affect the basic and novel features of the claimed subject matter .

[0074] With respect to the terms "comprising", "consisting of", and "consisting essentially of", when one of these three terms is used herein, the present disclosure and the claimed subject matter may include the use of either of the other two terms. Thus, in some embodiments where not otherwise explicitly stated, any example of "comprising" can be replaced by "consisting of" or by "consisting essentially of".

[0075] In some variations, the present invention is based on the selection and incorporation of a dispersant / drying agent for nanocellulose. As explained in the background, in many cases, it is desirable for composite products to incorporate discrete nanocellulose particles and prevent the binding (aggregation) of those particles during manufacture or use. When produced from cellulose-based biomass or by bacterial synthesis, nanocellulose is typically available as an aqueous dispersion. In thin aqueous dispersions, the nanocellulose particles remain non-aggregated or reversibly aggregate. In most polymeric cases, the aqueous dispersion itself cannot be introduced into the polymer matrix, and the water must first be removed. Even in aqueous solution systems, additive products containing as little water as possible are preferred in order to minimize the shipping costs, damage, and the amount of water introduced into the end-use product system along with the additive. For example, generally, it is not acceptable to introduce excessive water into the product system along with the additive, and thus the product must be dehydrated or dried beyond normal levels.

[0076] As used herein, a "dispersant / drying agent" is a chemical or combination of chemicals that functions to prevent irreversible aggregation of nanocellulose during drying or dehydration. The dispersant / drying agents disclosed herein are selected to hold discrete nanocellulose particles by preventing bonding between the nanocellulose particles while the aqueous dispersion is being dried or dehydrated (removal of water). In the absence of an effective dispersant / drying agent, irreversible bonding between the nanocellulose particles was observed through thermal drying to a 20 - 30 wt% solid slurry. The dispersant / drying agent also holds discrete nanocellulose particles while the nanocellulose is incorporated into the composite product and effectively and readily releases the individual nanocellulose particles during compounding of the composite product so that the effectiveness of the nanocellulose is maximized. The dispersant / drying agent can be selected to interact sufficiently with the surface of the nanocellulose and / or be uniformly distributed between the nanocellulose particles to reduce or prevent aggregation of the nanocellulose, thereby reducing or preventing self-bonding of the nanocellulose during drying.

[0077] Exemplary embodiments of the present invention will now be described. These embodiments are not intended to limit the scope of the present invention as claimed. The order of steps may be changed, some steps may be omitted, and / or other steps may be added. References to a first step, a second step, etc. herein are for the purpose of describing some embodiments only. Also, all references to "embodiments" are non-limiting and it should be understood that they are also alternatives with respect to any other disclosed embodiment unless the context clearly indicates otherwise.

[0078] Some variations of the present invention (a) from about 5 wt% to about 90 wt% of nanocellulose, and (b) from about 5 wt% to about 95 wt% of a dispersion / drying agent selected to be compatible with the nanocellulose to provide a nanocellulose dispersion concentrate comprising, wherein the dispersion / drying agent is selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and the nanocellulose dispersion concentrate is in solid form or liquid form.

[0079] In some embodiments, the nanocellulose is present at a concentration of about 10 wt% to about 70 wt%, and the dispersant / drying agent is present at a concentration of about 5 wt% to about 50 wt%. In various embodiments, the nanocellulose is present at a concentration of about, at least about, or up to about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 wt% (including all intermediate ranges). In these or other embodiments, the dispersant / drying agent is present at a concentration of about, at least about, or up to about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 wt% (including all intermediate ranges).

[0080] In some embodiments, the total of the nanocellulose and the dispersant / drying agent is about, at least about, or up to about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99, or 100 wt%. The nanocellulose dispersion concentrate may consist essentially of nanocellulose and the dispersant / drying agent, i.e., no other functional components may be present.

[0081] In some embodiments, the weight ratio of nanocellulose to dispersant / drying agent is selected from about 0.5 to about 2. In various embodiments, the weight ratio of nanocellulose to dispersant / drying agent is about, at least about, or up to about 0.1, 0.2, 0.5, 0.75, 0.9, 1, 1.1, 1.25, 1.5, 1.8, 2, 3, 4, 5, 6, 7, 8, 9, or 10 (including all intermediate ranges).

[0082] The nanocellulose may include cellulose nanocrystals, cellulose nanofibers, or a combination of cellulose nanocrystals and cellulose nanofibers. In some embodiments, the nanocellulose includes lignin-containing nanocellulose, for example, lignin-coated nanocellulose. Various types of nanocellulose will be described in more detail later.

[0083] The nanocellulose dispersion concentrate may be completely dry or may contain water at a concentration of about 0.1 wt% to about 70 wt%. In various embodiments, the nanocellulose dispersion concentrate contains about, or up to about 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, or 70 wt% water (including all intermediate ranges).

[0084] The nanocellulose dispersion concentrate may further include a liquid solvent such as a polar liquid solvent selected from the group consisting of water, C1-C8 alcohols, C2-C8 polyols, and combinations thereof. Additionally or alternatively, a nonpolar liquid solvent such as an aromatic hydrocarbon, for example, toluene, xylene, or a lignin derivative, may be present.

[0085] In some embodiments, the nanocellulose dispersion concentrate further includes an elastomer such as natural rubber or synthetic rubber. The concentration of the elastomer in the nanocellulose dispersion concentrate can be from about 0.1 wt% to about 50 wt%, for example, about 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 wt%.

[0086] The nanocellulose dispersion concentrate is a composition containing nanocellulose that can be redispersed in a target matrix (e.g., a polymer). The redispersibility of the nanocellulose dispersion concentrate can be tested or indicated in other systems that are not necessarily polymers, such as water, propanol, or other liquids or solids.

[0087] In certain embodiments, the nanocellulose dispersion concentrate is redispersed in an aqueous solution. In a typical example of such an embodiment, water is removed from the starting nanocellulose gel to transport the nanocellulose (to avoid transporting the weight of water), and different water is added back at the place of use. Preferably, the nanocellulose can be easily dispersed in water to form a nanocellulose gel without the need for homogenization or other mechanical refining (other than standard industrial mixing). For example, the nanocellulose dispersion concentrate powder can be very easily broken up into individual nanoparticles in water by tank stirring, for example, in 30 minutes.

[0088] The nanocellulose dispersion concentrate can be provided in a prepackaged form. The prepackaging can be, for example, a small container, tube, vial, jar, bag, supersack, or bucket of a prepackaging material that can be, for example, glass, plastic, coated paper, etc. In certain embodiments, the nanocellulose dispersion concentrate is provided in a powder form such as a dry powder. In some embodiments, the nanocellulose dispersion concentrate is part of a kit that includes the prepackaged nanocellulose dispersion concentrate along with instructions for use tailored to a specific masterbatch or composite system.

[0089] As used herein, "nanocellulose dispersion concentrate" refers to a composition containing at least nanocellulose and a dispersing / drying agent. "Nanocellulose dispersion masterbatch" refers to a composition containing at least nanocellulose, a dispersing / drying agent, and a carrier material. As can be understood according to the present specification, the nanocellulose dispersion concentrate can be directly used in the manufacture of nanocellulose-containing composite products. In some embodiments of manufacturing nanocellulose-containing composite products, it is beneficial to utilize a masterbatch.

[0090] In this specification, all references to "matrix polymer" will be understood to be exemplary references to "matrix material". Similarly, all references to "carrier polymer" will be understood to be exemplary references to "carrier material". Although numerous embodiments regarding polymers are described, this patent application is not explicitly limited to the use of nanocellulose dispersion concentrates in polymer systems.

[0091] Other variations of the present invention are (a) from about 1 wt% to about 75 wt% of nanocellulose, and (b) from about 1 wt% to about 89 wt% of a dispersion / drying agent selected to be compatible with the nanocellulose, and (c) from about 10 wt% to about 98 wt% of a carrier polymer different from the nanocellulose and the dispersion / drying agent to provide a nanocellulose dispersion masterbatch comprising, wherein the dispersion / drying agent is selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and the nanocellulose dispersion masterbatch is in solid form or liquid form.

[0092] In some masterbatch embodiments, the nanocellulose is present at a concentration of about 10 wt% to about 50 wt%, and the dispersant / drying agent is present at a concentration of about 5 wt% to about 75 wt%. In various embodiments, the nanocellulose is present at a concentration of about, at least about, or up to about 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, or 75 wt% (including all intermediate ranges). In these or other embodiments, the dispersant / drying agent is present at a concentration of about, at least about, or up to about 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85 wt% (including all intermediate ranges).

[0093] In some masterbatch embodiments, the total of the nanocellulose and the dispersant / drying agent is about, at least about, or up to about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99, or 100 wt%. The nanocellulose dispersion masterbatch may consist essentially of nanocellulose, a dispersant / drying agent, and a carrier polymer, i.e., no other functional components may be present.

[0094] In some masterbatch embodiments, the weight ratio of nanocellulose to dispersant / drying agent is selected from about 0.5 to about 2. In various embodiments, the weight ratio of nanocellulose to dispersant / drying agent is about, at least about, or up to about 0.1, 0.2, 0.5, 0.75, 0.9, 1, 1.1, 1.25, 1.5, 1.8, 2, 3, 4, 5, 6, 7, 8, 9, or 10 (including all intermediate ranges).

[0095] In some masterbatch embodiments, the weight ratio of carrier polymer to nanocellulose is selected from about 1 to about 100, for example, about, at least about, or up to about 2, 5, 10, 20, 50, or 80 (including all intermediate ranges).

[0096] The dispersant / drying agent can be selected to be compatible with the carrier polymer of the masterbatch. Alternatively, the carrier polymer can be selected to be compatible with the selected dispersant / drying agent.

[0097] The carrier polymer can be selected from the group consisting of polyolefins, polyols, polyamides, polylactic acid, polystyrene, polycarbonates, polyethylene terephthalate, and combinations thereof.

[0098] In a preferred embodiment of the nanocellulose dispersion masterbatch, the masterbatch is in solid powder form. The powder can be pelletized into spheres, cylinders, plates, or other geometric structures.

[0099] In other embodiments, the nanocellulose dispersion masterbatch is in liquid form, in a masterbatch solvent such as water, C1-C8 alcohols, C2-C8 polyols, or combinations thereof. In certain embodiments, the masterbatch is in powder form but contains water or other solvents absorbed by the solid.

[0100] The nanocellulose dispersion masterbatch can be provided in a prepackaged form. The prepackaging can be a small container, tube, vial, jar, or bag of a prepackaging material that can be, for example, glass, plastic, coated paper, etc. In certain embodiments, the nanocellulose dispersion masterbatch is provided in powder form such as a dry powder. In other embodiments, the nanocellulose dispersion masterbatch is pelletized or compressed into various geometric structures such as spheres, beads, rods, cylinders, plates. In some embodiments, the nanocellulose dispersion masterbatch is part of a kit that includes the prepackaged nanocellulose dispersion masterbatch with instructions for use tailored to a specific composite system.

[0101] Another variation of the present invention provides a nanocellulose-polymer composite product, which (a) about 0.05 wt% to about 10 wt% of nanocellulose, and (b) A dispersant / drying agent of about 0.05 wt% to about 10 wt%, selected to be compatible with nanocellulose and nanocellulose-polymer composite products, which is selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and (c) A carrier polymer of about 0.1 wt% to about 10 wt%, selected to be compatible with nanocellulose and the dispersant / drying agent, and (d) A matrix polymer of about 50 wt% to about 99.8 wt% and comprising.

[0102] In some embodiments of the composite product, the nanocellulose is present at a concentration of about 0.1 wt% to about 5 wt% in the nanocellulose-polymer composite product. The dispersant / drying agent may be present at a concentration of about 0.1 wt% to about 5 wt%. In various composite products, the nanocellulose is present at a concentration of about, at least about, or up to about 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt% (including all intermediate ranges). In these or other embodiments, the dispersant / drying agent is present at a concentration of about, at least about, or up to about 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt% (including all intermediate ranges).

[0103] In some composite products, the total of nanocellulose and the dispersant / drying agent is about, at least about, or up to about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 wt%. The nanocellulose-polymer composite product may consist essentially of nanocellulose, a dispersant / drying agent, a carrier polymer, and a matrix polymer, i.e., no other functional components may be present.

[0104] In some composite products, the weight ratio of nanocellulose to the dispersant / drying agent is selected from about 0.5 to about 2. In various composite products, the weight ratio of nanocellulose to the dispersant / drying agent is about, at least about, or up to about 0.1, 0.2, 0.5, 0.75, 0.9, 1, 1.1, 1.25, 1.5, 1.8, 2, 3, 4, 5, 6, 7, 8, 9, or 10 (including all intermediate ranges).

[0105] In some composite products, the weight ratio of the carrier polymer to nanocellulose is selected from about 1 to about 100, e.g., about, at least about, or up to about 2, 5, 10, 20, 50, or 80 (including all intermediate ranges).

[0106] In some composite products, the weight ratio of the matrix polymer to nanocellulose is selected from about 5 to about 2000, e.g., about, at least about, or up to about 5, 10, 50, 100, 200, 500, 1000, 1500, or 2000 (including all intermediate ranges).

[0107] In some composite products, the weight ratio of the matrix polymer to the nanocellulose dispersion concentrate is selected from about 1 to about 10000, e.g., about, at least about, or up to about 2, 10, 50, 100, 500, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, or 9000 (including all intermediate ranges).

[0108] In some composite products, the weight ratio of the matrix polymer to the nanocellulose dispersion masterbatch is selected from about 2 to about 10,000, such as, for example, about, at least about, or up to about 5, 10, 50, 100, 500, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, or 9000 (including all intermediate ranges).

[0109] In some embodiments of the composite product, the dispersant / drying agent is selected to be compatible with the carrier polymer, the matrix polymer, or both. Alternatively or additionally, the carrier polymer may be selected to be compatible with the dispersant / drying agent and / or the matrix polymer.

[0110] The carrier polymer may be selected from the group consisting of polyolefins, polyols, polyamides, polylactic acid, polystyrene, polycarbonates, polyethylene terephthalate, and combinations thereof. The carrier polymer may be the same polymer as the matrix polymer. Alternatively, the carrier polymer may be a different polymer than the matrix polymer. It is also possible to replace the carrier polymer with a non-polymeric carrier material. For example, the carrier material may be an organic liquid, an organic solid, an inorganic liquid, an inorganic solid, or a combination thereof.

[0111] In various nanocellulose-polymer composite products, the matrix polymer is selected from the group consisting of polyolefins, polyols, polyesters, polyamides, polylactic acid, polystyrene, polycarbonates, polyacrylates, polystyrene, styrenic rubbers, natural rubbers, synthetic rubbers, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyhydroxyalkanoates, poly(alkenedicarboxylates), silicones, carbonaceous polymers, and combinations or copolymers thereof.

[0112] Yet another variation of the present invention provides a nanocellulose-polymer composite product, which is (a) from about 0.05 wt% to about 15 wt% of nanocellulose, and (b) A dispersing / drying agent of about 0.05 wt% to about 15 wt% selected to be compatible with nanocellulose and nanocellulose-polymer composite products, which is selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and (c) about 50 wt% to about 99.9 wt% of a matrix polymer and comprising.

[0113] In some embodiments, for example, when the nanocellulose dispersion concentrate is directly incorporated into the matrix polymer without passing through a masterbatch, the carrier polymer is absent. In certain embodiments, the carrier polymer can also be selectively removed from the composite product, for example, by hydrolysis or melting.

[0114] In some embodiments of the composite product without a carrier polymer, the nanocellulose is present in the nanocellulose-polymer composite product at a concentration of about 0.1 wt% to about 5 wt%, for example, about 0.5 wt% to about 2 wt%. The nanocellulose-polymer composite product may essentially consist of nanocellulose, a dispersing / drying agent, and a matrix polymer.

[0115] In some composite products without a carrier polymer, the weight ratio of the matrix polymer to the nanocellulose is selected from about 2 to about 2000, for example, about, at least about, or up to about 5, 10, 50, 100, 200, 500, 1000, 1500, or 2000 (including all intermediate ranges).

[0116] In some composite products that do not contain a carrier polymer, the weight ratio of the matrix polymer to the nanocellulose dispersion concentrate is selected from about 1 to about 10,000, such as about, at least about, or up to about 2, 5, 10, 50, 100, 500, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, or 9000 (including all intermediate ranges).

[0117] The dispersant / drying agent is selected based on the compatibility of the selected nanocellulose with the end-use product. In some embodiments, the dispersant / drying agent contains chemical components and / or functional groups that can hydrogen bond with polar groups present in the nanocellulose. Nanocellulose polar groups include at least -OH and to some extent -O-. When functionalized nanocellulose is utilized, other polar groups may be present. In other embodiments, the dispersant / drying agent does not necessarily hydrogen bond with polar groups present in the nanocellulose. In these or other embodiments, the dispersant / drying agent contains components that serve as particle spacers. The particle spacers not only physically distribute the nanocellulose particles but also do not repel the nanocellulose phase. Repelling the nanocellulose is important because it leads to self-association and aggregation of the nanocellulose, resulting in irreversible bonding during drying. Rather, the particle spacers within the dispersant / drying agent prevent the nanocellulose from associating in this way, thereby reducing or preventing irreversible aggregation.

[0118] The dispersant / drying agent can also be selected based on economics (cost or availability), the ability to produce it as a by-product on-site, or its environmental sustainability. In some embodiments, the dispersant / drying agent is bio-based, biodegradable, and / or compostable.

[0119] In some embodiments, the dispersant / drying agent is a functionalized polyalkylene wax that is compatible with nanocellulose and optionally nanocellulose-polymer composite products. As used herein, a "functionalized" hydrogen-containing compound is one in which at least one hydrogen atom has been replaced by a functional group. For example, -H can be replaced by -OH, -COOH, =O, or other oxygen-containing functional groups. In certain embodiments, for example, -H can be replaced by a non-oxygen-containing functional group, such as a metal, halogen, nitrogen, sulfur, or a group containing these components.

[0120] The functionalized polyalkylene wax can be a functionalized polyethylene wax, a functionalized polypropylene wax, a functionalized polybutylene wax, or a combination thereof. In certain embodiments, the dispersant / drying agent is a low molecular weight oligomer or polymer of ethylene or functionalized ethylene. When functionalized ethylene is utilized, each repeating unit can have an average of about 0.1 to about 4.0 hydrogen atoms replaced by other functional groups. The number average degree of polymerization of ethylene or functionalized ethylene can be from 2 to 1000, such as 5 to 500. In various embodiments, the number average degree of polymerization of ethylene or functionalized ethylene is at least, or at most, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 25, 50, 75, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 (including all intermediate ranges).

[0121] In some embodiments, the dispersant / drier is a copolymer of (a) one or more C2-C4 olefins and (b) maleic anhydride. The C2 olefin is ethylene, the C3 olefin is propylene, and the C4 olefin is 1-butene, 2-butene, isobutene, butadiene, or a combination thereof. The C2-C4 olefins can be functionalized olefins such as functionalized ethylene. Maleic anhydride is an organic compound having the formula C2H2(CO)2O and is the acid anhydride of maleic acid. For the purposes herein, a polymer of maleic acid or its salt is also considered to be a polymer of maleic anhydride. For example, maleic anhydride can be produced from 5-hydroxymethylfurfural, which itself can be derived from biomass (glucose dehydration). Also, the C2-C4 olefins can be produced from biomass, for example, by dehydration of alcohols produced by fermentation of sugars.

[0122] The copolymer of the C2-C4 olefin and maleic anhydride can be a block copolymer, an alternating copolymer, a random copolymer, or a combination thereof. When the olefin is ethylene, for example, the copolymer can be poly(ethylene-alt-maleic anhydride) and / or poly(ethylene-graft-maleic anhydride). A graft copolymer is a type of copolymer in which one or more blocks of a homopolymer are grafted as branches onto the main chain, meaning a branched copolymer in which one or more side chains of a homopolymer are attached to the backbone of the main chain. Thus, poly(ethylene-graft-maleic anhydride) can also be considered a polymer of functionalized ethylene in which ethylene is functionalized by maleic acid or maleic anhydride. This type of copolymer can also be called maleated polyethylene.

[0123] In some embodiments, the dispersant / drying agent is a copolymer of (a) one or more C2-C4 olefins and (b) acrylic acid. The C2 olefin is ethylene, the C3 olefin is propylene, and the C4 olefin is 1-butene, 2-butene, isobutene, butadiene, or a combination thereof. The C2-C4 olefins can be functionalized olefins such as functionalized ethylene. Acrylic acid is an organic compound having the formula CH2=CHCOOH. For the purposes herein, a polymer of acrylic acid or its salts is also considered to be a polymer of acrylic anhydride.

[0124] The copolymer of C2-C4 olefins and acrylic acid can be a block copolymer, an alternating copolymer, a random copolymer, or a combination thereof. Typically, acrylic acid polymerizes across its double bond, similar to ethylene polymerization (e.g., free radical copolymerization), to yield a graft copolymer or a copolymer that can be considered a polymer of functionalized ethylene where ethylene is functionalized by acrylic acid.

[0125] In some embodiments, the dispersant / drying agent comprises a polyol selected from ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerol, butylene glycol, polybutylene glycol, butanediol, or a combination thereof. In some embodiments, the polyol is esterified with a fatty acid such as stearic acid.

[0126] In certain embodiments, the dispersing / drying agent is glycerol, or contains glycerol, or is dissolved in glycerol as a solvent. Glycerol has a high boiling point (about 290 °C) and three hydroxyl groups (one OH group per C atom). When the nanocellulose is dried, glycerol can enter between the nanocellulose particles by forming hydrogen bonds, thereby preventing the formation of H bonds and resulting aggregation that could otherwise occur between the nanocellulose particles. The high boiling point of glycerol is beneficial for use in dry powders. The powder can be dispersed in a hydrophobic polymer matrix such as polylactic acid (PLA). Glycerol between the nanocellulose particles may function as a plasticizer when the PLA is extruded, or the glycerol may be removed by vacuum during processing, or a combination thereof.

[0127] The dispersing / drying agent can be a polar molecule having a vapor pressure of less than 1.0 bar at 100 °C and optionally a vapor pressure of greater than 0.001 bar, greater than 0.01 bar, or greater than 0.1 bar at 180 °C. A relatively high vapor pressure at high temperatures can be beneficial, for example, when it is desirable to remove the dispersing / drying agent during the formulation of the final polymer. The polar additive can be a polyol, such as ethylene glycol, glycerol, butanediol, etc. In some embodiments, the polar additive contains at least 0.5 OH groups per carbon atom, for example, at least 1.0 OH groups per carbon atom. The OH groups prevent irreversible bonding between the nanoparticles during drying. The polar additive can be organic or inorganic.

[0128] In some embodiments, the dispersing / drying agent contains a fatty acid. A fatty acid is a carboxylic acid having a long aliphatic chain that is saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of 4 to 28 even-numbered carbon atoms. The fatty acids herein can be selected, for example, from caprylic acid, capric acid, lauric acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, or combinations thereof. Unsaturated and / or branched fatty acids may be used.

[0129] In some embodiments, the dispersant / drier comprises a fatty alcohol. The fatty alcohol is a long-chain alcohol that is a straight-chain primary alcohol having from 4 to 26 carbon atoms in the range. Exemplary fatty alcohols include lauryl alcohol (dodecanol), stearyl alcohol, and oleyl alcohol. The fatty alcohol may be an oily liquid (in the case of a smaller number of carbon atoms) or a waxy solid. The fatty alcohol typically has an even number of carbon atoms and a single alcohol group (-OH) bonded to the terminal carbon. Some are unsaturated and some are branched. Fatty alcohols that are unsaturated and / or branched may be used. Fatty alcohols having an odd number of carbon atoms may be used. Ethylene can be oligomerized, and the oligomer can undergo hydroformylation to yield an odd aldehyde, which can subsequently be hydrogenated. For example, from 1-decene, C 11 alcohol is produced.

[0130] In some embodiments, the dispersant / drier comprises a siloxane-based additive. The siloxane-based additive may include a siloxane or polysiloxane material having one or more functional groups selected from the group consisting of methyl, C2-C 24 alkyl, epoxide, hydroxy, amino, carboxyl, acrylate, and combinations thereof. An exemplary siloxane-based additive is polydimethylsiloxane.

[0131] Siloxane-based additives preferably provide a hydrophobic portion and a hydrophilic portion. Typically, the hydrophobic and hydrophilic portions are at opposite ends of the molecule or polymer chain. The siloxane-based additives preferably exist as an emulsion in water. In certain embodiments, the dispersion / drying agent comprises an alkyl ester polydimethylsiloxane emulsion. While drying the nanocellulose with the emulsion, the nanocellulose surrounds the oil phase droplets during drying, and when the water is removed, the nanocellulose is drawn into the oil phase. In certain embodiments, the siloxane-based additive functions as an aid to prevent hydrogen bonding during drying.

[0132] In some embodiments, the dispersion / drying agent comprises starch, such as cationic starch, amphoteric starch, thermoplastic starch, or combinations thereof.

[0133] Cationic starch is positively charged, which may be desirable when the nanocellulose particles have a slightly negative surface charge. Exemplary cationic starches include quaternary ammonium cationic starch and quaternary amino cationic starch.

[0134] Amphoteric starch is a modified starch containing both positively and negatively charged substituents. Exemplary amphoteric starches contain a quaternary ammonium cationic group and a phosphate group as an anionic group.

[0135] Thermoplastic starch is starch plasticized by relatively low levels (e.g., 15 - 30 wt%) of molecules that can hydrogen bond to the hydroxyl groups of the starch. Starch plasticizers can be water, polyols (e.g., glycerol), pentaerythritol, sugar alcohols (e.g., sorbitol), poly(oxyethylene), poly(oxypropylene), nonionic surfactants, anionic surfactants, or combinations thereof.

[0136] In some embodiments, the dispersant / dryer contains fine particles. The fine particles can be selected from, but are not limited to, clay, nanoclay, talc, wollastonite, calcium carbonate (e.g., precipitated calcium carbonate), silica, mica, kaolin, nickel, glass fiber, bentonite, biotite, illite, kaolin, vermiculite, zeolite, carbon fiber, carbon nanotube, graphene, or combinations thereof. In some embodiments, the fine particles preferably have a surface charge that is positively charged. Known surface treatments such as treatment with an acidic solution at low pH can be used to provide a surface charge on the fine particles. Other surface treatments for the fine particles may be performed, such as silylation to improve interfacial adhesion.

[0137] In certain embodiments, the dispersant / dryer contains at least one fatty acid and at least one fine particle. The fatty acid and the fine particle may be present in a non-reactive form or may be reacted with each other in the dispersant / dryer. In these embodiments, the dispersant / dryer can include, for example, (a) a fatty acid selected from caprylic acid, capric acid, lauric acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, or combinations thereof, and (b) clay, nanoclay, talc, wollastonite, calcium carbonate, silica, mica, kaolin, limonite, glass fiber, bentonite, biotite, illite, kaolin, vermiculite, zeolite, or combinations thereof. Exemplary dispersants / dryers having both a fatty acid and a fine particle include talc and stearic acid. Another exemplary dispersant / dryer having both a fatty acid and a fine particle includes calcium carbonate and stearic acid.

[0138] In various embodiments, the dispersant / dryer contains an ionomer in association with a metal cation such as calcium or zinc to form a neutral salt. In various embodiments, the dispersant / dryer contains a component having a positive charge (e.g., surface-charged fine particles or cationic starch) in association with an anion to form a neutral salt.

[0139] The dispersing / drying agent must be selected based on the properties of the nanocellulose to be dispersed and dried. In particular, the hydrophilicity of the nanocellulose can at least partially determine the appropriate dispersing / drying agent. When selecting the appropriate dispersing / drying agent, composition, particle size, melting point, and other factors can also be considered.

[0140] A hydrophilic molecule or part of a molecule is one in which the interaction with water and other polar substances is more thermodynamically favorable than the interaction with oil or other hydrophobic solvents. Hydrophilic molecules are usually charge-polarized and can form hydrogen bonds. On the other hand, hydrophobic molecules are not attracted to water or other polar molecules. Nanocellulose is usually very hydrophilic, but it can also be otherwise. In some embodiments, for example, lignin-containing nanocellulose is relatively hydrophobic. Since lignin itself is not purely hydrophobic, there is usually still some hydrophilicity in lignin-containing nanocellulose.

[0141] In a preferred embodiment, the hydrophilicity of the dispersing / drying agent (or part of the dispersing / drying agent) is selected to match or be similar to the hydrophilicity of the nanocellulose, and thus they bind to each other and the dispersing / drying agent separates the regions of the nanocellulose.

[0142] In some embodiments, the hydrophilicity of the dispersing / drying agent is selected based at least in part on the hydrophilicity of the carrier polymer in the masterbatch and / or the matrix polymer (or other matrix material) in the final composite. The dispersing / drying agent can be designed, for example, to have both hydrophilic and hydrophobic components at the two ends of the molecule. In such embodiments, for example, the hydrophilic end adheres to the nanocellulose surface, while the hydrophobic end is captured on the hydrophobic polymer during compounding.

[0143] In some embodiments, the dispersant / drying agent is selected based on its melting point. In these embodiments, the dispersant / drying agent at least partially melts during the drying of the nanocellulose dispersion concentrate. When the dried nanocellulose dispersion concentrate is cooled, the dispersant / drying agent returns to a solid phase in which the nanocellulose is uniformly dispersed. As an example, polyethylene wax (including functionalized modifications) has a melting point in the range of approximately 100 to 150 °C.

[0144] In addition to enhancing the dispersion of the nanocellulose, the dispersant / drying agent may have other functions. For example, in some embodiments, the dispersant / drying agent may function as a compatibilizer (between the matrix polymer and the nanocellulose), a plasticizer, a density modifier, a viscosity modifier, or a toughness modifier. The dispersant / drying agent may also provide auxiliary properties such as color or texture to the final composite product or masterbatch.

[0145] In some variations, the technical scheme provides the following steps (see also the flowchart of FIG. 12). First, noting that the principles of the present invention can be applied to polymers or non-polymers as matrix materials, a matrix material is selected based on engineering and product needs. Second, a nanocellulose material is selected such that the nanocellulose is expected to improve some properties of the matrix material (e.g., mechanical strength, viscosity, etc.). Third, a dispersion / drying agent is selected based on the selected nanocellulose material such that the dispersion / drying agent is compatible with the nanocellulose. Fourth, a nanocellulose dispersion concentrate is produced by combining the dispersion / drying agent, the nanocellulose, and optionally other components. Fifth, a nanocellulose dispersion masterbatch is produced by combining the nanocellulose dispersion concentrate with a carrier material (e.g., a carrier polymer). Sixth, the nanocellulose dispersion masterbatch is combined with the selected matrix material to produce a composite product (e.g., a polymer-nanocellulose composite). The step of producing the nanocellulose dispersion masterbatch may be omitted in some embodiments, in which case, for producing the composite product, the nanocellulose dispersion concentrate is directly combined with the selected matrix material.

[0146] Some variations provide a method for producing a nanocellulose dispersion concentrate, the method comprising providing a nanocellulose gel comprising nanocellulose and water, and selecting a dispersion / drying agent that is compatible with the nanocellulose, the dispersion / drying agent being selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and mixing the nanocellulose gel and the dispersion / drying agent, and During or after the mixing step, at least a portion of the water is removed to produce a nanocellulose dispersion concentrate, and optionally, the nanocellulose dispersion concentrate is milled to produce a powder, and the nanocellulose dispersion concentrate is recovered in solid or liquid form and includes.

[0147] The water in the nanocellulose gel can be at least partially replaced by another polar solvent. Usually, nanocellulose is produced in an aqueous solution, but this is not strictly essential. The biomass fractionation procedure for producing nanocellulose uses, in principle, a polar solvent such as glycerol or ethanol instead of or in addition to water. Thus, although most of this disclosure refers to water as the main or only polar solvent in the starting nanocellulose gel, it will be understood that one or more polar solvents other than water can be utilized.

[0148] Some variations provide a method for producing a nanocellulose dispersion masterbatch, the method comprising providing a nanocellulose gel comprising nanocellulose and water, and selecting a dispersion / drying agent compatible with the nanocellulose, the dispersion / drying agent being selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and mixing the nanocellulose gel and the dispersion / drying agent, and during or after the mixing step, removing (i.e., drying) at least a portion of the water to produce a nanocellulose dispersion concentrate, and optionally, milling the nanocellulose dispersion concentrate to produce a concentrate powder, and During mixing the nanocellulose gel and the dispersion / drying agent, and / or during removing at least a part of water, and / or after removing at least a part of water (thereby generating a nanocellulose dispersion masterbatch), and / or during pulverizing the nanocellulose dispersion concentrate to generate a concentrate powder (if implemented), and / or after pulverizing the nanocellulose dispersion concentrate to generate a concentrate powder (if implemented), introducing a carrier polymer into the nanocellulose dispersion concentrate to generate a nanocellulose dispersion masterbatch, and Optionally, pulverizing the nanocellulose dispersion masterbatch to generate a masterbatch powder, and recovering the nanocellulose dispersion masterbatch, preferably in a solid form, and comprise.

[0149] Some variations provide a method for manufacturing a nanocellulose-polymer composite product, the method comprising: providing a nanocellulose gel comprising nanocellulose and water, and selecting a dispersion / drying agent to be compatible with the nanocellulose and the nanocellulose-polymer composite product, the dispersion / drying agent being selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and mixing the nanocellulose gel and the dispersion / drying agent, and removing at least a part of water (i.e., drying) during or after the mixing step to generate a nanocellulose dispersion concentrate, and Optionally, pulverizing the nanocellulose dispersion concentrate to generate a concentrate powder, and During mixing the nanocellulose gel and the dispersion / drying agent, and / or during removing at least a part of water, and / or after removing at least a part of water (thereby generating a nanocellulose dispersion masterbatch), and / or during (if carried out) grinding the nanocellulose dispersion concentrate to produce a concentrate powder, and / or after (if carried out) grinding the nanocellulose dispersion concentrate to produce a concentrate powder, introducing a carrier polymer into the nanocellulose dispersion concentrate to produce a nanocellulose dispersion masterbatch, and Optionally, grinding the nanocellulose dispersion masterbatch to produce a masterbatch powder, and Mixing the nanocellulose dispersion masterbatch with a matrix polymer and mechanically and / or thermally processing the combined material to produce a nanocellulose-polymer composite product, and Recovering the nanocellulose-polymer composite product and comprise.

[0150] Certain variations provide a method for manufacturing a nanocellulose-polymer composite product without using a carrier polymer, the method comprising providing a nanocellulose gel comprising nanocellulose and water, and selecting a dispersion / drying agent to be compatible with the nanocellulose and the nanocellulose-polymer composite product, the dispersion / drying agent being selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof, and mixing the nanocellulose gel and the dispersion / drying agent, and removing at least a part of water (i.e., drying) during or after the mixing step to produce a nanocellulose dispersion concentrate, and Optionally, grinding the nanocellulose dispersion concentrate to produce a concentrate powder; mixing the nanocellulose dispersion concentrate with a matrix polymer and mechanically and / or thermally processing the combined materials to produce a nanocellulose-polymer composite product; recovering the nanocellulose-polymer composite product; and

[0151] In some variations, a method for producing a nanocellulose dispersion concentrate comprises: providing a nanocellulose gel comprising nanocellulose and water; selecting a dispersion / drying agent compatible with the nanocellulose, wherein the dispersion / drying agent is selected from the group consisting of waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glyceride esters, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamides, starches, cellulose derivatives, microparticles, and combinations or reaction products thereof; mixing the nanocellulose gel and the dispersion / drying agent; removing at least a portion of the water during or after the mixing step to produce a nanocellulose dispersion concentrate; optionally, grinding the nanocellulose dispersion concentrate to produce a powder; recovering the nanocellulose dispersion concentrate in solid or liquid form; and

[0152] In some embodiments, the step of removing at least a portion of the water comprises high-shear mixing with heating to a temperature of at least 50°C.

[0153] In some embodiments, the method further comprises combining the nanocellulose dispersion concentrate with a carrier material to form a nanocellulose dispersion masterbatch. The carrier material can be, for example, a carrier polymer.

[0154] In some embodiments, the method further includes combining the nanocellulose dispersion masterbatch with a matrix material to form a nanocellulose-containing composite product.

[0155] The matrix material can be a matrix polymer. For example, the matrix polymer can be selected from the group consisting of polyolefins, polyols, polyesters, polyamides, polylactic acid, polystyrene, polycarbonates, polyacrylates, polystyrene, styrenic rubbers, natural rubbers, synthetic rubbers, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyhydroxyalkanoates, poly(alkenedicarboxylates), silicones, carbonaceous polymers, and combinations or copolymers thereof.

[0156] Alternatively or additionally, the matrix material can be a material other than a polymer, such as paper, paperboard, fibers and wood composites (e.g., particle board and molded pulp products), emulsions, hydrogels, carbon, organic solids, inorganic solids, oils, organic liquids, inorganic liquids, cementitious materials (e.g., concrete or cement), minerals, ceramics, metals, metal alloys, glass, and combinations thereof. The non-polymer matrix material can be, for example, an adhesive matrix, a battery electrode matrix, a bioink matrix, or an electronic ink matrix.

[0157] In embodiments where the masterbatch is made, the drying step for producing the concentrate can be carried out at the same location or a different location from the step of making the masterbatch. Also, the drying step for producing the concentrate can be carried out at the same location or a different location from the step of making the final composite (combining the matrix material with the masterbatch or concentrate).

[0158] In some embodiments, the method further includes combining the nanocellulose dispersion concentrate directly with the matrix material (without going through a masterbatch) to form a nanocellulose-containing composite product.

[0159] When the nanocellulose dispersion concentrate is added directly to the matrix material, the matrix material can be a matrix polymer such as a polymer selected from the group consisting of polyolefins, polyols, polyesters, polyamides, polylactic acid, polystyrene, polycarbonates, polyacrylates, polystyrene, styrenic rubbers, natural rubbers, synthetic rubbers, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyhydroxyalkanoates, poly(alkenedicarboxylates), silicones, carbonaceous polymers, and combinations or copolymers thereof.

[0160] Alternatively or additionally, the matrix material can be selected from the group consisting of paper, paperboard, fiber and wood composites, emulsions, hydrogels, carbon, organic solids, inorganic solids, oils, organic liquids, inorganic liquids, cementitious materials, minerals, ceramics, metals, metal alloys, glass, and combinations thereof.

[0161] The drying step (removing at least a portion of the water) to form the concentrate can be performed at the same location as the step of combining the nanocellulose dispersion concentrate directly with the matrix material. Alternatively or additionally, the drying step to form the concentrate can be performed at a location different from the step of combining the nanocellulose dispersion concentrate with the matrix material.

[0162] In any of the methods disclosed herein, the order of the steps can differ in any logical order. Also, the location of the steps can differ such that the overall process is located at one or more sites. For example, a nanocellulose dispersion masterbatch can be made at a first location and transported to a second location to compound a polymer to make a polymer composite, and the polymer composite itself can be transported to a third location to make a final commercial product.

[0163] All methods disclosed in this specification can be carried out batchwise, continuously, or semi - continuously. Feed throughputs can vary widely, including laboratory scale, pilot scale, semi - works scale, and commercial scale.

[0164] The step of drying the nanocellulose gel with the dispersant / drying agent is preferably carried out under mechanical forces such as shear force, centrifugal force, compressive force, or combinations thereof. Usually, shear force is utilized for the drying step. High - shear mixing techniques under heating include, but are not limited to, homogenization, sigma - blade mixing, rotor - stator mixing, static in - line mixing, and extrusion. In certain embodiments, a melt rheometer can be utilized to achieve high - shear mixing. Preferably, the high - shear mixing device is configured to allow continuous or intermittent vapor release, such as venting of water vapor, during drying. It should be noted that the step of mixing the nanocellulose gel and the dispersant / drying agent can be configured as a pre - mixing step before drying. The pre - mixing step does not necessarily need to be high - shear mixed.

[0165] Also, the drying step is preferably carried out at a high temperature and optionally under vacuum, for example, at about 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, or 150 °C. The drying temperature can be based, in part, on the melting point of the dispersant / drying agent. The high temperature can be achieved by addition of heat and / or heat generated from the mixing force. The drying step can be carried out for an appropriate time, for example, from about 1 minute to about 4 hours.

[0166] The step of removing at least a portion of the water (referred to herein as "drying", regardless of the mechanism or apparatus) can be carried out during mixing if the mixing is carried out at at least the boiling point of water at the mixing pressure and water vapor can be released from the mixing apparatus. Removal of water can be achieved simply by evaporation, but not necessarily so. For example, the processing time and the amount of water that needs to be removed during drying can be significantly reduced by pre-concentration with a centrifuge, filter press, or belt press. In some embodiments, sufficient water removal is achieved by centrifugation or filtration without evaporation. Typically, water (or other polar solvents) is evaporated from the nanocellulose gel. When water is removed during mixing, the dispersing / drying agent prevents the nanocellulose from aggregating and irreversibly self-bonding.

[0167] The nanocellulose dispersion concentrate can contain water at a moisture concentration of about, or up to about 70 wt%, 60 wt%, 50 wt%, 45 wt%, 40 wt%, 35 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt%, 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2.5 wt%, 2 wt%, 1.5 wt%, 1 wt%, 0.9 wt%, 0.8 wt%, 0.7 wt%, 0.6 wt%, 0.5 wt%, 0.4 wt%, 0.3 wt%, 0.2 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, or 0 wt% (including any intermediate range), e.g., water at about 0.5 - 1.5 wt% or about 0.1 - 7 wt%.

[0168] Nanocellulose can be characterized by unbound moisture and bound moisture. Thus, the choice of drying method and the arrangement and operating parameters of the apparatus can be made based on the ratio of unbound moisture to bound moisture in the drying system feed. This ratio generally differs for lignin-containing nanocellulose compared to non-lignin-containing nanocellulose when all other factors are the same.

[0169] If comminution is carried out to produce a concentrate powder or a masterbatch powder, it can generally be carried out using conventional devices such as (but not limited to) a hammer mill, a ball mill, a jet mill, an impact crusher, a pulverizer, a cage mill, or a grinder. The comminution step, if carried out, can be selected based on the drying technique and the nature of the dry material to be comminuted.

[0170] The nanocellulose dispersion masterbatch can contain water at a moisture concentration of about, or up to about 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2.5 wt%, 2 wt%, 1.5 wt%, 1 wt%, 0.9 wt%, 0.8 wt%, 0.7 wt%, 0.6 wt%, 0.5 wt%, 0.4 wt%, 0.3 wt%, 0.2 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, or 0 wt% (including any intermediate ranges).

[0171] Some or all of the dispersing / drying agent (and any solvent) can be removed during compounding or after the composite is made. For example, when using glycerol as the dispersing / drying agent or solvent, the glycerol can be removed from the extruder vent. As another example, when using wax as the dispersing / drying agent, the wax can be selectively melted from the composite. When the dispersing / drying agent is removed, it is preferred that the matrix polymer and / or the carrier polymer fill the space left by the dispersing / drying agent so that the nanocellulose remains non-aggregated even after some or all of the dispersing / drying agent has been removed.

[0172] The present invention is applicable to various types of nanocellulose materials. Nanocellulose can be produced by breaking down biomass into submicron cellulose nanofibers or nanocrystals using chemical means, mechanical means, or a combination of chemical and mechanical means. Other methods for producing nanocellulose, such as bacterial nanocellulose and nanocellulose derived from tunicates, are also available.

[0173] Generally, the production of nanocellulose occurs in two main stages. The first stage is the purification of biomass to remove most of the non-cellulose components in the biomass, such as lignin, hemicellulose, extractives, and inorganic contaminants. This stage is usually carried out by conventional pulping and bleaching. For the production of cellulose nanofibrils, the second stage usually involves mechanical refining of the purified biomass fibers, with or without chemical or enzymatic treatment to reduce the amount of mechanical energy required. In the case of cellulose nanocrystals, the second stage usually involves acid hydrolysis of the purified fibers followed by high-shear mechanical treatment.

[0174] Nanocellulose can be obtained by fractionating lignocellulosic biomass in the presence of an acid catalyst, a solvent for lignin, and water to produce a cellulose-rich solid, and then mechanically treating the cellulose-rich solid to produce nanocellulose or a precursor thereof. In some embodiments, the solvent for lignin is an aliphatic alcohol (e.g., ethanol), and the acid catalyst is a sulfur-containing compound selected from the group consisting of sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, elemental sulfur, sulfonic acid, lignosulfonic acid, and combinations thereof.

[0175] Nanocellulose can be obtained from the AVAP® lignocellulosic biomass fractionation process. It has been found that a very high degree of crystallinity can be generated and maintained during the formation of nanofibers or nanocrystals without the need for an enzyme or a separate acid treatment step to hydrolyze the amorphous cellulose. The high degree of crystallinity can lead to mechanically strong fibers or good physical reinforcement properties, which are advantageous, for example, for composites, reinforced polymers, and high-strength spun fibers and textiles.

[0176] In some embodiments, the nanocellulose comprises hydrophobic nanocellulose. In these or other embodiments, the nanocellulose comprises hydrophilic nanocellulose. In certain embodiments, the nanocellulose comprises lignin-containing cellulose nanocrystals (e.g., lignin-coated cellulose nanocrystals) and / or lignin-containing cellulose nanofibers (e.g., lignin-coated cellulose nanofibers).

[0177] In some embodiments, the nanocellulose material is at least partially hydrophobic by virtue of at least a portion of the lignin adhering to the surface of the cellulose-rich solid (nanocellulose precursor). In these or other embodiments, the nanocellulose material is at least partially hydrophobic by virtue of at least a portion of the lignin adhering to the surface of the nanocellulose material after mechanical refining.

[0178] In some embodiments, the acid is SO2 at a concentration of about 5 wt% to about 30 wt%. In some embodiments, the fractionation temperature is from about 130 °C to about 180 °C. In some embodiments, the fractionation time is from about 15 minutes to about 4 hours. The process can be controlled such that a portion of the solubilized lignin intentionally returns and adheres to the surface of the cellulose-rich solid, thereby making the cellulose-rich solid at least partially hydrophobic.

[0179] Process conditions that facilitate the attachment of lignin to the fiber can be used, such as extended time and / or temperature, or a reduced concentration of the lignin solvent. Alternatively or additionally, one or more washing steps may be performed to attach at least a portion of the lignin solubilized during the first fractionation. One approach is to wash with water rather than a solution of water and solvent. Since lignin does not normally dissolve in water, it will begin to precipitate. Optionally, other conditions such as pH and temperature may be varied during fractionation, washing, or other steps to optimize the amount of lignin attached to the surface. Optionally, a method for producing a hydrophobic nanocellulose material may further include chemically modifying the lignin to increase the hydrophobicity of the nanocellulose material.

[0180] Alternatively or additionally, nanocellulose can be obtained by fractionating lignocellulosic biomass in the presence of steam or hot water, optionally using a fractionation catalyst (e.g., acetic acid), to obtain a cellulose-rich solid, and then producing nanocellulose by mechanical refining of the cellulose-rich solid. These steps can be collectively referred to as a hydrothermal-mechanical treatment. The reaction solution for fractionation can consist essentially of steam or hot water. Note that "steam or hot water" refers to water in one or more phases determined by thermodynamics at a given temperature and pressure. The temperature of the fractionation can be from about 120 °C to about 220 °C, for example, from about 150 to 200 °C. The water can be in the form of steam, superheated steam, supersaturated steam, or pressurized liquid water. In some embodiments, the fractionation step is carried out with a residence time of from about 1 minute to about 60 minutes, for example, about 2, 2.5, 3, 3.5, 4, 5, 7.5, 10, 12.5, 15, 20, 25, 30, 35, 40, 45, 50, or 55 minutes.

[0181] In embodiments using hydrothermal-mechanical treatment, the cellulose-rich solids typically contain a significant concentration of lignin. Thus, these embodiments can be beneficial when hydrophobic nanocellulose is desired. Hydrothermal-mechanical treatment can produce nanocellulose that can be called nanolignocellulose due to its high lignin content. Nanolignocellulose can contain, on a completely dry, ash-free, and acetyl-free basis, from about 35 wt% to about 80 wt% cellulose nanofibrils, cellulose microfibrils, or a combination thereof, from about 15 wt% to about 45 wt% lignin, and from about 5 wt% to about 20 wt% hemicellulose. Of the lignin present, some can coat the nanocellulose particles, while the remainder of the lignin is inside the nanocellulose particles.

[0182] Nanocellulose is preferably obtained from lignocellulosic biomass. As used herein, "lignocellulosic biomass" means any material containing cellulose and lignin. Lignocellulosic biomass can also contain hemicellulose. A mixture of one or more types of biomass can be used. In some embodiments, the biomass feedstock includes both a lignocellulosic component (e.g., those described above) in addition to a sucrose-containing component (e.g., sugarcane or energy cane) and / or a starch component (e.g., corn, wheat, rice, etc.). Various moisture levels can be associated with the starting biomass. The biomass feedstock need not be dry, but it can be. Generally, the biomass is in the form of microparticles or chips, although the particle size of the starting biomass is not critical.

[0183] Biomass raw materials for producing nanocellulose can be selected from hardwood, softwood, forest residues, eucalyptus, industrial waste, pulp and paper waste, consumer waste, or combinations thereof. In some embodiments, agricultural residues including lignocellulosic biomass associated with food crops, annual grasses, energy crops, or other annually renewable raw materials are utilized. Exemplary agricultural residues include, but are not limited to, corn stover, corn fiber, wheat straw, sugarcane bagasse, sugarcane straw, rice straw, oat straw, barley straw, miscanthus, energy cane straw / residue, or combinations thereof.

[0184] Other nanocellulose sources include bacterial nanocellulose, nanocellulose derived from tunicates, pulp treatment with sulfuric acid, pulp treatment with 2,2,6,6 - tetramethylpiperidine-1-oxyl radical (TEMPO), or pulp treatment with cellulase enzymes. In some embodiments, the nanocellulose used herein is not bacterial nanocellulose, not derived from tunicates, not obtained from sulfuric acid hydrolysis, not obtained from TEMPO, and / or not obtained from enzymatic hydrolysis of lignocellulosic biomass or cellulose.

[0185] As intended herein, "nanocellulose" is broadly defined to include various cellulosic materials including, but not limited to, microfibrillated cellulose, nanofibrillated cellulose, microcrystalline cellulose, nanocrystalline cellulose, and particulate or fibrillated dissolved pulp. In certain embodiments, nanocellulose includes particles having at least one length dimension (e.g., diameter) on the nanometer scale. In some embodiments, nanocellulose has particles with all average dimensions greater than 1 micron, such as in the case of certain microfibrillated cellulose.

[0186] "Nanofibrillated cellulose" or equivalently "cellulose nanofibril" means cellulose fibers or regions containing particles or fibers of nanometer size, or particles or fibers of both micron size and nanometer size. "Nanocrystalline cellulose" or equivalently "cellulose nanocrystal" means cellulose particles, regions, or crystals containing domains of nanometer size, or domains of both micron size and nanometer size. "Micron size" includes 1 μm to 100 μm, and "nanometer size" includes 0.01 nm to 1000 nm (1 μm). In any of these materials, larger domains (including long fibers) may also be present.

[0187] The specific size and shape of nanocellulose can range from the nanometer scale to the micron scale in terms of width and / or length. Cellulose nanofibers typically have a width dimension of 5 - 20 nm and a length dimension of 500 - 5000 nm, and contain both amorphous and crystalline domains of cellulose. Cellulose nanocrystals typically have a width of 3 - 8 nm and a length of 100 - 500 nm and are mainly crystalline. Although these ranges and dimensions are typical, the present invention encompasses all nanocellulose materials regardless of particle shape or particle size.

[0188] Some embodiments use blends of nanocellulose crystals and fibrils. Blends of nanocellulose crystals and fibrils can contain 1% - 99% nanocellulose crystals and 99% - 1% nanocellulose fibrils, respectively. In various embodiments, blends of nanocellulose crystals and fibrils contain 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 98% (all weight percentages) of nanocellulose crystals, with the remainder of the nanocellulose being nanocellulose fibrils.

[0189] Some embodiments use a blend of cellulose nanofibrils and microfibrils. The blend of cellulose nanofibrils and cellulose microfibrils can contain from 1% to 99% cellulose nanofibrils and from 99% to 1% cellulose microfibrils, respectively. In various embodiments, the blend of cellulose nanofibrils and microfibrils contains 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 98% (all weight percentages) of cellulose nanofibrils, with the remainder being cellulose microfibrils.

[0190] Since nanocellulose fibrils are much larger than nanocellulose crystals, one feature of the nanocellulose blend is the wide range of particle sizes present. The width of the nanocellulose crystals can vary, for example, from about 2 nanometers to about 10 nanometers, or from about 3 nanometers to about 6 nanometers. The length of the nanocellulose crystals can vary, for example, from about 50 nanometers to about 500 nanometers, or from about 100 nanometers to about 350 nanometers. The width of the nanocellulose fibrils can vary, for example, from about 5 nanometers to about 100 nanometers, or from about 10 nanometers to about 50 nanometers. The length of the nanocellulose fibrils can vary, for example, from about 200 nanometers to about 10 microns, or from about 400 nanometers to about 3 microns. The average nanocellulose particle width in the blend can vary from about 3 nanometers to about 50 nanometers, for example, from about 5 nanometers to about 30 nanometers. The average nanocellulose particle length in the blend can vary from about 50 nanometers to about 5 microns, for example, from about 100 nanometers to about 2 microns.

[0191] In some variations, the method for producing nanocellulose is (a) providing a lignocellulosic biomass feedstock, and (b) fractionating the raw material in the presence of an acid, a solvent for lignin, and water to produce a cellulose-rich solid and a liquid containing hemicellulose and lignin; (c) mechanically treating the cellulose-rich solid to form cellulose fibrils and / or cellulose crystals, thereby producing a nanocellulose material having a crystallinity of at least 60% (i.e., cellulose crystallinity); (d) recovering the nanocellulose material; comprising.

[0192] In some embodiments, the acid is selected from the group consisting of sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, lignosulfonic acid, and combinations thereof. In certain embodiments, the acid is sulfur dioxide.

[0193] In some embodiments, during step (c), the cellulose-rich solid is treated with a total mechanical energy of less than about 5000 kilowatt-hours per ton of cellulose-rich solid, such as less than about 4000, 3000, 2000, or 1000 kilowatt-hours per ton of cellulose-rich solid. The energy consumption can be measured with any other suitable device. An ammeter that measures the current drawn by the motor driving the mechanical treatment device is one way to obtain an estimate of the total mechanical energy.

[0194] The mechanical treatment in step (c) can form or release nanofibrils and / or nanocrystals in cellulose using one or more known techniques such as, for example, grinding, crushing, beating, ultrasonic treatment, or any other means, but is in no way limited thereto. In essence, any type of mill, or apparatus for physically separating fibers, can be utilized. Such mills are well known in the industry and include, but are not limited to, valley beaters, single disk refiners, double disk refiners, conical refiners including both wide and narrow angles, cylindrical refiners, homogenizers, microfluidizers, and other similar grinding or crushing devices. See, for example, Smook, Handbook for Pulp&Paper Technologists, Tappi Press, 1992; and Hubbe et al., “Cellulose Nanocomposites: A Review,” BioResources 3(3), 929 - 980 (2008).

[0195] The degree of mechanical treatment can be monitored by any of several means throughout the process. Certain optical instruments can provide continuous data regarding fiber length distribution and % fines, both of which can be used to define the endpoint of the mechanical treatment step. Time, temperature, and pressure can vary during the mechanical treatment. For example, in some embodiments, ultrasonic treatment at ambient temperature and pressure for about 5 minutes to 2 hours can be utilized.

[0196] In some embodiments, a portion of the cellulose - rich solid is converted to nanofibrils, while the remainder of the cellulose - rich solid is not fibrillated. In various embodiments, about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or substantially all of the cellulose - rich solid is fibrillated into nanofibrils.

[0197] In some embodiments, some of the nanofibrils are converted to nanocrystals, while the remainder of the nanofibrils are not converted to nanocrystals. In various embodiments, about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or substantially all of the nanofibrils are converted to nanocrystals. During drying, a small amount of nanocrystals can also aggregate and form nanofibrils.

[0198] After mechanical treatment, the nanocellulose material can be classified by particle size. A portion of the material can undergo another process, such as enzymatic hydrolysis to yield glucose. Such materials may, for example, have good crystallinity but may not have the desired particle size or degree of polymerization.

[0199] Step (c) may further include treatment of the cellulose-rich solid with one or more enzymes or one or more acids. When an acid is used, the acid can be selected from the group consisting of sulfur dioxide, sulfurous acid, lignosulfonic acid, acetic acid, formic acid, and combinations thereof. Acids associated with hemicellulose, such as acetic acid or uronic acid, can be used alone or in combination with other acids. Step (c) may also include treatment of the cellulose-rich solid with heat. In some embodiments, step (c) does not use any enzymes or acids.

[0200] In step (c), when an acid is used, the acid can be a strong acid such as sulfuric acid, nitric acid, or phosphoric acid. Weaker acids can be used at higher temperatures and / or for longer times. Instead of, or potentially in addition to, an acid, enzymes that hydrolyze cellulose (i.e., cellulase) and possibly hemicellulose (i.e., having hemicellulase activity) can be used in step (c) in a sequential configuration before or after acid hydrolysis.

[0201] In some embodiments, the method includes enzymatically treating the cellulose-rich solid to hydrolyze the amorphous cellulose. In other embodiments, or sequentially before or after the enzymatic treatment, the method may include acid treating the cellulose-rich solid to hydrolyze the amorphous cellulose.

[0202] In some embodiments, the method further includes enzymatically treating the nanocrystalline cellulose. In other embodiments, or sequentially before or after the enzymatic treatment, the method further includes acid treating the nanocrystalline cellulose.

[0203] Optionally, the enzymatic treatment can be used before the mechanical treatment or perhaps simultaneously with the mechanical treatment. However, in a preferred embodiment, the enzymatic treatment is not necessary to hydrolyze the amorphous cellulose or to weaken the fiber wall structure prior to the isolation of the nanofibers.

[0204] After the mechanical treatment, the nanocellulose can be recovered. The separation of cellulose nanofibrils and / or nanocrystals can be achieved using an apparatus that can break down the ultrastructure of the cell wall while preserving the integrity of the nanofibrils. For example, a homogenizer can be used. In some embodiments, cellulose aggregate fibrils having component fibrils in the range of 1 to 100 nm in width are recovered, where the fibrils are not completely separated from each other.

[0205] The method may further include bleaching the cellulose-rich solid before step (c) and / or as part of step (c). Alternatively or additionally, the method may further include bleaching the nanocellulose material during and / or after step (c). Any known bleaching technique or sequence including enzymatic bleaching can be used.

[0206] Optionally, the method further comprises hydrolyzing the amorphous cellulose to glucose in step (b) and / or step (c), recovering the glucose, and fermenting the glucose to a fermentation product. Optionally, the method further comprises recovering, fermenting, or further processing the hemicellulose sugars derived from hemicellulose. Optionally, the method further comprises recovering, combusting, or further processing the lignin.

[0207] The nanocellulose material may comprise nanofibrillated cellulose or may consist essentially of nanofibrillated cellulose. The nanocellulose material may comprise nanocrystalline cellulose or may consist essentially of nanocrystalline cellulose. In some embodiments, the nanocellulose material may comprise nanofibrillated cellulose and nanocrystalline cellulose or may consist essentially of nanofibrillated cellulose and nanocrystalline cellulose.

[0208] In some embodiments, the crystallinity of the cellulose-rich solid (i.e., the nanocellulose precursor material) is at least 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86% or more. In these or other embodiments, the crystallinity of the nanocellulose material is at least 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86% or more. The crystallinity can be measured using any known technique. For example, X-ray diffraction and solid 13 C nuclear magnetic resonance can be utilized.

[0209] In some embodiments, the nanocellulose material is characterized by an average degree of polymerization of from about 100 to about 3000, such as about 125, 150, 175, 200, 225, 250, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 2000, 2500, or 2600. For example, the nanocellulose material may be characterized by an average degree of polymerization of from about 300 to about 700, or from about 150 to about 250. When the nanocellulose material is in the form of nanocrystals, it may have a degree of polymerization of less than 100, such as about 75, 50, 25, or less than 10. A portion of the material may have a degree of polymerization exceeding 3000, 4000, or 5000.

[0210] In some embodiments, the nanocellulose material is characterized by a degree of polymerization distribution having a single peak. In other embodiments, the nanocellulose material is characterized by a degree of polymerization distribution having two peaks, such as one peak centered in the range of 150 - 250 and another peak centered in the range of 300 - 700.

[0211] In some embodiments, the nanocellulose material is characterized by an average length - to - width aspect ratio of the particles of from about 10 to about 1000, such as about 15, 20, 25, 35, 50, 75, 100, 150, 200, 250, 300, 400, or 500. Nanofibrils are generally associated with a higher aspect ratio than nanocrystals. The nanocrystals can have, for example, a length range of about 100 nm to 500 nm and a diameter of about 4 nm, which results in an aspect ratio of 25 - 125. The nanofibrils can have a length of about 2000 nm and a diameter range of 5 - 50 nm, which results in an aspect ratio of 40 - 400. In some embodiments, the aspect ratio is less than 50, less than 45, less than 40, less than 35, less than 30, less than 25, less than 20, less than 15, or less than 10.

[0212] In some embodiments, the nanocellulose contains less than 0.05 wt% sulfur, for example, about 0.02 wt% sulfur or less, and may also contain undetectable sulfur. In some embodiments, the nanocellulose does not contain sulfate half-ester groups bonded to the surface of the nanocellulose particles because these groups can reduce the thermal stability of the nanocellulose.

[0213] Optionally, the nanocellulose itself is functionalized with one or more surface functional groups to yield a nanocellulose derivative. Such functionalization can be carried out, for example, to improve compatibility with a matrix polymer or to impart special properties to the nanocellulose. Since nanocellulose has a large surface area and a high concentration of surface hydroxyl groups, targeted surface modification can introduce substantially any desired surface functionality.

[0214] For example, the nanocellulose derivative can be selected from the group consisting of nanocellulose esters, nanocellulose ethers, nanocellulose ether esters, alkylated nanocellulose compounds, cross-linked nanocellulose compounds, acid-functionalized nanocellulose compounds, base-functionalized nanocellulose compounds, and combinations thereof. Functionalization or derivatization of various types of nanocellulose can be used, such as functionalization with polymers, chemical surface modification, functionalization with nanoparticles (i.e., in addition to nanocellulose, other nanoparticles), modification with inorganic substances or surfactants, or biochemical modification.

[0215] In some embodiments, the nanocellulose is combined with a polymer or a combination of polymers while forming a melt phase, for example, in polymer extrusion, injection molding, compression molding, calendering, etc. For example, the nanocellulose can be introduced into the melt phase as part of a nanocellulose dispersion concentrate and / or as part of a nanocellulose dispersion masterbatch.

[0216] One or more additives can be introduced during the process, where the additives can be selected from the group consisting of compatibilizers, plasticizers, antioxidants, colorants, flame retardants, nucleating agents, viscosity modifiers, density modifiers, and combinations thereof. Exemplary additives include, but are not limited to, clay, nanoclay, talc, wollastonite, calcium carbonate, silica, mica, kaolin, nickel, glass fiber, carbon, cellulose fiber, aramid fiber, polyimide fiber, jute fiber, polyethylene fiber, polyethylene terephthalate fiber, polyamide fiber, and combinations thereof. In some embodiments, carbonaceous additives such as carbon fiber, carbon nanotube, graphene, lignin-derived carbon, or lignin are used.

[0217] The matrix polymer can be selected from a wide range as already described. The polymer or combination of polymers can include polyester, polyolefin, polyamide, polystyrene, styrene-based rubber, polyurethane, polyurea, poly(amide-eneamine), polyanhydride, polyacrylate, polyhydroxyalkanoate, poly(alkenedicarboxylate), silicone, thermoplastic resin elastomer, thermoplastic polyurethane (TPU), synthetic rubber, natural rubber, or combinations or copolymers thereof.

[0218] In some embodiments, the polymer or combination of polymers includes polylactic acid. In some embodiments, the polymer or combination of polymers includes polyhydroxyalkanoate. In some embodiments, the polymer or combination of polymers includes aliphatic-aromatic copolyesters. In various embodiments, the polymer or combination of polymers includes polylactic acid, aliphatic-aromatic copolyesters, poly(butylene adipate co-terephthalate), poly(butylene adipate), or poly(butylene succinate). In some embodiments, the polymer or combination of polymers includes polyethylene and / or polypropylene.

[0219] In some embodiments, the polymer or combination of polymers includes polyester, polyolefin, polyamide, polystyrene, styrene rubber, natural rubber, synthetic rubber, polyurethane, polyurea, poly(amide-eneamine), polyanhydride, polyacrylate, polyhydroxyalkanoate, poly(alkenedicarboxylate), silicone, thermoplastic resin elastomer, thermoplastic polyurethane (TPU), synthetic rubber, natural rubber, or combinations or copolymers thereof. Some polymer blends include polylactic acid, polyhydroxyalkanoate, aliphatic-aromatic copolyester, both polylactic acid and aliphatic-aromatic copolyester, polyethylene, and / or polypropylene.

[0220] The polymer that can be included in the composite product can be, for example, hydrophobic, partially hydrophobic, or lipophilic. Hydrophilic polymers can be modified to be at least partially hydrophobic using a suitable coating or combination of components (e.g., an interpenetrating network of polymers).

[0221] In some embodiments, the polymer is selected from polyester, polyolefin, polyamide, polystyrene, styrene rubber, polyurethane, polyurea, poly(amide-eneamine), polyanhydride, polyacrylate, polyhydroxyalkanoate, poly(alkenedicarboxylate), silicone, and combinations or copolymers thereof (e.g., aliphatic-aromatic copolyester).

[0222] In various embodiments, the polymer is selected from the group consisting of polyethylene, polypropylene, polybutene, polyisobutylene, polybutadiene, polyisoprene, poly(ethylene-co-acrylic acid), poly(lactic acid) (or polylactic acid), poly(glycolic acid) (or polyglycolide), poly(hydroxybutyrate), poly(butylene adipate-co-terephthalate), poly(butylene succinate), poly(hydroxybutyrate-co-hydroxyvalerate), poly(ethylene terephthalate), polyvinyl alcohol, polystyrene, poly(butyl acrylate), poly(tert-butyl acrylate-co-ethyl acrylate-co-methacrylic acid), poly(ethyl acrylate), poly(2-ethylhexyl acrylate), poly(methyl acrylate), polyacrylonitrile, poly(acrylonitrile-co-methyl acrylate), poly(styrene-co-maleic anhydride), poly(methyl methacrylate), poly(alkyl methacrylate), polyvinylcyclohexane, poly(bisphenol A carbonate), poly(propylene carbonate), poly(1,4-butylene adipate), poly(1,4-butylene succinate), poly(1,4-butylene terephthalate), poly(ethylene succinate), poly(vinyl acetate), poly(propylene glycol), poly(tetrahydrofuran), poly(ethyl vinyl ether), polydimethylsiloxane, nylon (aliphatic polyamide), and combinations or copolymers thereof. Also, a carbonaceous polymer may be incorporated into the composite. Examples of carbonaceous polymers include polyacenaphthylene, graphite, graphene, carbon fiber, and lignin.

[0223] The polymer or copolymer can be produced by polymerizing one or more monomers selected from the group consisting of acrylic, amide, carbon, carbonate, diene, ester, ether, fluorocarbon, imide, olefin, organic acid (such as lactic acid, glycolic acid, succinic acid, hydroxypropionic acid, etc.), styrene, siloxane, vinyl acetal, vinyl chloride and vinylidene, vinyl ester, vinyl ether, vinyl ketone, vinyl pyridine, vinyl pyrrolidone, and combinations thereof.

[0224] The polymer in the polymer composite can include a thermoplastic polymer, a thermosetting polymer, or a combination thereof. Thermosetting polymers include, but are not limited to, polyurethanes, polyesters, polyureas, polyisoprenes (including natural rubber or synthetic rubber), phenol-formaldehyde resins, polyepoxides, polyimides, polycyanurates, polyfurans, silicones, and combinations or copolymers thereof.

[0225] In some embodiments, the polymer is particularly an elastomer. Exemplary elastomers include natural rubber (such as natural latex unvulcanized rubber) and synthetic rubber. Natural rubber is mainly poly-cis-isoprene. Synthetic rubbers are made from various petroleum-based monomers. The most common synthetic rubber is styrene-butadiene rubber (SBR) obtained from the copolymerization of styrene and 1,3-butadiene. Other synthetic rubbers are prepared from isoprene (2-methyl-1,3-butadiene, which gives polyisoprene), chloroprene (2-chloro-1,3-butadiene), and isobutylene (methylpropene) with a small proportion of isoprene for crosslinking (butyl rubber is produced).

[0226] In some embodiments, the matrix polymer is bio-based, biodegradable, and / or compostable. In these or other embodiments, the carrier polymer is bio-based, biodegradable, and / or compostable. In some embodiments, the matrix polymer or the carrier polymer is a biodegradable polymer such as any polymer described in Vroman and Tighzert, “Biodegradable Polymers,” Materials 2009, 2, 307-344, which is incorporated herein by reference, or includes these. In some embodiments of the present invention, for example, as measurable by 13C analysis, the nanocellulose-polymer composite product has a renewable carbon content of at least 50%, 60%, 70%, 80%, 90%, 95%, or 100%.

[0227] Some methods further include forming a cured or finished polymer composite from the melt phase using well-known polymer processing techniques. A variety of industrial and consumer products can be manufactured from the nanocellulose-polymer composite product. These include any known product containing a polymer, as well as new products (e.g., engineering composites). Many types of products are possible, including films, coatings, packaging, appliances, fibers, fabrics, clothing, durable consumer goods, non-woven fabrics, and the like.

[0228] The final composite product can be in the form of, for example, pellets, extruded parts, injection molded parts, blow molded parts, spun fibers, laminated sheets, films, foams, containers, bags, engineering parts, 3D printing substrates, 3D printed parts, or combinations thereof.

[0229] Nanocellulose-polymer composite products can be 3D printed. Three-dimensional (3D) printing or additive manufacturing is a process in which an object is created in its three-dimensional form using a special printer. The printer receives instructions from a design file created on a computer with the assistance of a 3D modeling program. The file or digital blueprint of the object to be printed is then sliced into two-dimensional (2D) representations and sent to the printer. Layers of material are formed according to the information contained in the file; the layers are continuously added until the complete object is printed. The process of 3D printing requires much more time and involves significant equipment investment compared to 2D printing, but offers a wide range of advantages such as the ability to print virtually any geometric structure in principle. In some embodiments of 3D printing, masterbatch and matrix polymer are added to the 3D printer. In some embodiments, a nanocellulose dispersion concentrate and a matrix polymer are added directly to the 3D printer. In some embodiments, a nanocellulose-polymer composite is produced and then introduced into a 3D printer to produce a selected geometric object. It should be noted that 3D printing can also be used to produce unique masterbatch pellet geometries by supplying a carrier polymer and a nanocellulose dispersion concentrate to the 3D printer. This may be desirable for marketing purposes.

[0230] In some of the composite products provided herein, products in which nanocellulose is dispersed have a higher tensile modulus than the polymer alone or than a composite that is identical except for not containing a dispersant / drying agent.

[0231] In some of the composite products provided herein, products in which nanocellulose is dispersed have a higher tensile modulus than the polymer alone or than a composite that is identical except for not containing a dispersant / drying agent.

[0232] In some composite products provided herein, products in which nanocellulose is dispersed have a higher compressive modulus compared to the polymer alone or to a composite that is identical except for not containing a dispersant / dryer.

[0233] In some composite products provided herein, products in which nanocellulose is dispersed have higher toughness compared to the polymer alone or to a composite that is identical except for not containing a dispersant / dryer.

[0234] In some composite products provided herein, products in which nanocellulose is dispersed have better moisture barrier and / or oxygen barrier properties compared to the polymer alone or to a composite that is identical except for not containing a dispersant / dryer.

[0235] Due to the inherent properties of the nanocellulose particles and as a result of the dispersant / dryer, such that those nanocellulose particles are well-dispersed in the composite, the tensile modulus, compressive modulus, toughness, and other properties of the composite product are improved.

[0236] In the final composite, or in the nanocellulose dispersion concentrate or masterbatch, the degree of dispersion of the nanocellulose can be measured or qualitatively evaluated. The degree of dispersion is inversely proportional to the degree of aggregation. In the case of a complete homogeneous dispersion, there is no particle aggregation. The present invention does not require a complete dispersion such that all single nanoparticles are isolated from all other nanoparticles.

[0237] The nanocellulose dispersion can be measured or qualitatively evaluated using techniques such as, for example, scanning electron microscopy, transmission electron microscopy, interference microscopy, confocal laser scanning microscopy, optical microscopy, small-angle X-ray scattering, atomic force microscopy, dynamic light scattering, nanotomography, or thermogravimetric analysis. Figures 1 - 8 (see Examples 1 - 8, respectively) are optical micrographs demonstrating good dispersion (no aggregation), in contrast to Figure 11, which is an optical micrograph showing insufficient dispersion (significant particle aggregation).

[0238] The nanocellulose dispersion can also be measured or qualitatively evaluated using a calibration technique in which a verified polymer having a known nanocellulose dispersion is tested for relevant properties. Next, the test sample is measured for the same properties, which is correlated to the degree of nanocellulose dispersion using a predetermined graph, equation, or look-up table.

[0239] In the final composite product, the dispersant / drier can be present in the same phase as the nanocellulose, in the same phase as the matrix material, and / or in a separate phase (or, as described above, no longer present). The dispersant / drier may be disposed between the nanocellulose particles and the matrix material. In some embodiments, the dispersant / drier surrounds the nanocellulose particles. The carrier material can be present in the same phase as the nanocellulose, in the same phase as the matrix material, and / or in a separate phase (or not present).

[0240] In some embodiments, the method includes forming a structural object comprising a nanocellulose-containing composite product, or a derivative thereof.

[0241] In some embodiments, the method includes forming a foam or aerogel comprising a nanocellulose-containing composite product, or a derivative thereof.

[0242] In some embodiments, the method includes combining a nanocellulose-containing composite product, or a derivative thereof, with one or more other carbon materials to form a composite comprising nanocellulose, carbon, and a matrix material.

[0243] In some embodiments, the method includes forming a film comprising a nanocellulose-containing composite product, or a derivative thereof. In certain embodiments, the film is optically transparent and flexible.

[0244] In some embodiments, the method includes forming a coating or coating precursor comprising a nanocellulose-containing composite product, or a derivative thereof.

[0245] In some embodiments, the nanocellulose-containing composite product is configured as a catalyst, a catalyst substrate, or a co-catalyst. In some embodiments, the nanocellulose-containing composite product is configured to electrochemically transmit or store current or voltage.

[0246] In some embodiments, the nanocellulose-containing composite product is incorporated into a filter, a membrane, or other separation device.

[0247] In some embodiments, the nanocellulose-containing composite product is incorporated as an additive into a coating, a paint, or an adhesive. In some embodiments, the nanocellulose-containing composite product is a cement additive.

[0248] The nanocellulose-containing composite product can include any of the disclosed compositions. A number of composite products are possible. For example, the composite product can be selected from the group consisting of a structural object, a foam, an aerogel, a carbon composite, a film, a coating, a coating precursor, a current or voltage carrier, a filter, a membrane, a catalyst, a catalyst substrate, a coating or coating additive, a paint or paint additive, an adhesive or adhesive additive, an ink or ink additive, a cement additive, a paper coating or paper additive, a thickener, a rheology modifier, an additive for drilling fluids, and combinations or derivatives thereof.

[0249] The nanocellulose-containing composite products provided herein are expected to have high oxygen barrier and affinity to wood fibers for use in food packaging and printing paper, and thus are suitable as coating materials. Alternatively or additionally, the nanocellulose-containing composite product can be incorporated into a product, for example, to improve barrier properties or to improve nucleation.

[0250] The nanocellulose-containing composite product provided herein is suitable as an additive for improving the durability of paints and protects paints and varnishes from wear caused by ultraviolet radiation.

[0251] The nanocellulose-containing composite product provided herein is suitable as a thickener in food and cosmetic products. Nanocellulose can be used as a thickener with thixotropic, biodegradable, and dimensional stability (stable against temperature and salt addition). The nanocellulose-polymer composite product provided herein is suitable as a Pickering stabilizer for emulsions and particle-stabilized foams. The large surface area of nanocellulose, combined with its biodegradability, makes nanocellulose an attractive material for very porous and mechanically stable aerogels.

[0252] In other embodiments, the nanocellulose dispersion masterbatch is used as or incorporated into structural objects, foams, aerogels, carbon composites, films, coatings, coating precursors, current or voltage carriers, filters, membranes, catalysts, catalyst substrates, coating additives, paint additives, adhesive additives, cement additives, paper coatings, thickeners, rheology modifiers, additives for drilling fluids, and combinations or derivatives thereof.

[0253] In other embodiments, the nanocellulose dispersion concentrate is incorporated into structural objects, foams, aerogels, carbon composites, films, coatings, coating precursors, current or voltage carriers, filters, membranes, catalysts, catalyst substrates, coating additives, paint additives, adhesive additives, cement additives, paper coatings, thickeners, rheology modifiers, additives for drilling fluids, and combinations or derivatives thereof. Other uses suitable for the present invention include high-strength spun fibers and textiles, advanced composites, barrier films, paints, lacquers, adhesives, switchable optical elements, pharmaceuticals, drug delivery systems, bone replacements, dental restorations, paper, packaging, building products, additives for food and cosmetics, and hydrogels.

[0254] Aerospace and transportation composites can benefit from the disclosed nanocellulose dispersion concentrates or masterbatches. Automotive applications include nanocellulose composites containing polypropylene, polyamide (e.g., nylon), or polyester (e.g., PBT).

[0255] The nanocellulose dispersion concentrates or masterbatches provided herein are suitable as strength enhancing additives for renewable and biodegradable composites. The dispersant / dryer can function as a binder between two organic phases for improving fracture toughness and preventing crack formation for applications in packaging, construction materials, appliances, and renewable fibers.

[0256] The nanocellulose dispersion concentrates or masterbatches provided herein are suitable as transparent and dimensionally stable strength enhancing additives for applications in flexible displays, flexible circuits, printable electronics, and flexible solar panels.

[0257] The nanocellulose dispersion concentrates or masterbatches provided herein are suitable for composites and cement additives that allow for crack reduction and increases in toughness and strength. Foamed porous nanocellulose-concrete hybrid materials allow for lightweight structures with crack reduction and increased strength.

[0258] Strength enhancement by nanocellulose increases both the bonding area and bonding strength for applications in high-strength, bulky, high filler content papers and boards with enhanced moisture and oxygen barrier properties. The pulp and paper industry can particularly benefit from the nanocellulose dispersion concentrates or masterbatches provided herein.

[0259] In some embodiments, the nanocellulose dispersion concentrate is incorporated as a thickening or rheology modifying agent. For example, the nanocellulose dispersion concentrate can be an additive in drilling or fracturing fluids such as (but not limited to) oil recovery fluids and / or gas recovery fluids.

[0260] The nanocellulose dispersion concentrate can generally be useful in any system that can benefit from the incorporation of the nanocellulose dispersion concentrate. As discussed herein, the systems include, but are by no means limited to, polymers, oligomers, paper, paperboard, fiber and wood composites, emulsions, hydrogels, carbon, organic solids, inorganic solids, oils, organic liquids, inorganic liquids, cementitious materials (e.g., concrete or cement), minerals, ceramics, metals, metal alloys, glass, or combinations thereof. The non-polymer matrix material can be, for example, an adhesive matrix, a battery electrode matrix, a bioink matrix, or an electronic ink matrix.

Examples

[0261] Examples Example 1: Preparation of Nanocellulose Dispersion Concentrate and Nanocellulose-Polypropylene Composite The lignin-coated nanofibrils are obtained by fractionating lignocellulosic biomass (softwood chips) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce a cellulose-rich solid, and then mechanically treating the cellulose-rich solid to produce lignin-coated nanofibrils. The lignin-coated nanofibrils are present in an aqueous suspension containing about 3 wt% solids. The aqueous suspension is sometimes referred to as a nanocellulose gel.

[0262] The dispersant / drying agent is selected to be a copolymer of ethylene and maleic anhydride, based on lignin-coated nanofibrils and a selected matrix polymer (polypropylene). A specific dispersant / drying agent is Honeywell A-C® 573A wax (Honeywell Performance Materials and Technologies, Morris Plains, New Jersey, USA), which is an ethylene maleic anhydride copolymer in powder form. Honeywell A-C® 573A wax is a low molecular weight copolymer of maleic anhydride and propylene or ethylene. Functionalization of nonpolar propylene or ethylene with maleic anhydride provides a copolymer having both nonpolar and polar characteristics. According to Honeywell, maleic anhydride provides polarity without polymer degradation.

[0263] The starting nanocellulose dispersion concentrate is produced by combining, under mechanical agitation, an aqueous suspension of 2,917 grams of lignin-coated nanofibrils with 88 grams of the above-mentioned dispersing / drying agent to yield a starting slurry. The starting nanocellulose dispersion slurry initially contains approximately 3 wt% nanocellulose (lignin-coated nanofibrils) and approximately 94 wt% water. The starting slurry is dried by a semi-batch process under heat and shear using a Brabender PL200 Plasti-Corder torque rheometer equipped with a Haake Rheomix 3000 mixer, mixing at a mixing blade speed of 100 revolutions per minute (RPM) and a temperature of 120 °C. As water evaporates and the volume within the mixer bowl decreases, slurry is continuously added to the rheometer. The process is continued for approximately 90 minutes until all of the slurry is fed and all of the moisture has evaporated from the material, at which point the dry concentrate is removed from the mixer. The processing time and the amount of water that needs to be removed during drying can be significantly reduced, for example, by pre-concentrating the slurry by centrifugation. During the heat mixing, water is evaporated from the nanocellulose gel. As water is removed in the shear mixing, aggregation and self-bonding of the nanocellulose are prevented and the wax phase serves as a spacer between the nanocellulose particles.

[0264] When essentially all of the water has been removed from the starting nanocellulose dispersion slurry, a nanocellulose dispersion concentrate is obtained that contains approximately 50 wt% nanocellulose (lignin-coated nanofibrils) and approximately 50 wt% dispersing / drying agent. Although it is preferred to remove all of the water, it is also possible for some residual moisture to remain in the nanocellulose dispersion concentrate. It will also be recognized that other nanocellulose concentrations can be used for the nanocellulose dispersion concentrate.

[0265] The nanocellulose dispersion concentrate obtained above is then ground into a powder in a Bel-Art micromill. The resulting powder is then dispersed in polypropylene as follows. 4 parts by weight of the nanocellulose dispersion concentrate (meaning 2 parts of nanocellulose and 2 parts of dispersant / drying agent) and 96 parts by weight of a polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) are combined and mixed in a Brabender torque rheometer. The rheometer is operated for 11 minutes at a speed of 40 RPM and a temperature of 150 °C. The resulting nanocellulose-polymer composite is shown in the optical micrograph (magnification 100x) of Figure 1, showing 2 wt% nanocellulose (lignin-coated nanofibrils) uniformly dispersed in polypropylene.

[0266] Example 2: Preparation of Nanocellulose Dispersion Concentrate and Nanocellulose-Polypropylene Composite Lignin-coated nanofibrils are obtained by fractionating lignocellulosic biomass (softwood chips) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce a cellulose-rich solid, and then mechanically treating the cellulose-rich solid to produce lignin-coated nanofibrils. The lignin-coated nanofibrils are present in an aqueous suspension (gel) containing approximately 3 wt% solids.

[0267] The dispersant / drying agent is selected to be a copolymer of ethylene and acrylic acid based on the lignin-coated nanofibrils and the selected matrix polymer (polypropylene). A specific dispersant / drying agent is Honeywell AClyn® 295A wax (Honeywell Performance Materials and Technologies, Morris Plains, New Jersey, USA), which is a zinc ionomer of an ethylene acrylic acid copolymer in powder form neutralized to 98% with zinc (for corrosion protection).

[0268] The starting nanocellulose dispersion slurry is produced by combining, under mechanical agitation, an aqueous suspension of 2,917 grams of lignin-coated nanofibrils with 88 grams of the above-described dispersing / drying agent. The starting nanocellulose dispersion slurry initially contains approximately 3 wt% nanocellulose (lignin-coated nanofibrils) and approximately 94 wt% water. The starting slurry is dried by a semi-batch process under heat and shear using a Brabender PL200 Plasti-Corder torque rheometer equipped with a Haake Rheomix 3000 mixer, mixing at a mixing blade speed of 100 revolutions per minute (RPM) and a temperature of 120 °C. As water evaporates and the volume within the mixer bowl decreases, slurry is continuously added to the rheometer. The process continues for approximately 90 minutes until all of the slurry has been fed and all of the moisture has evaporated from the material, at which point the dry concentrate is removed from the mixer. The processing time and the amount of water that needs to be removed during drying can be significantly reduced, for example, by pre-concentrating the slurry by centrifugation. During the heat mixing, water is evaporated from the nanocellulose gel. When water is removed in the shear mixing, aggregation and self-bonding of the nanocellulose are prevented, and the wax phase serves as a spacer between the nanocellulose particles.

[0269] When essentially all of the water has been removed from the starting nanocellulose dispersion slurry, a nanocellulose dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanofibrils) and approximately 50 wt% dispersing / drying agent results. Although it is preferred to remove all of the water, it is also possible for some residual moisture to remain in the nanocellulose dispersion concentrate. It will also be recognized that other nanocellulose concentrations can be used for the nanocellulose dispersion concentrate.

[0270] The nanocellulose dispersion concentrate obtained above is then ground into a powder in a Bel-Art micromill. The resulting powder is then dispersed in polypropylene as follows. 4 parts by weight of the nanocellulose dispersion concentrate and 96 parts by weight of a polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) are combined and mixed in a Brabender torque rheometer. The rheometer is operated for 11 minutes at a speed of 40 RPM and a temperature of 150 °C. The resulting nanocellulose-polymer composite is shown in the optical micrograph (magnification 100x) of Figure 2, showing 2 wt% nanocellulose (lignin-coated nanofibrils) uniformly dispersed in polypropylene.

[0271] Example 3: Preparation of Nanocellulose Dispersion Concentrate and Nanocellulose-Polypropylene Composite Lignin-coated nanofibrils are obtained by fractionating lignocellulosic biomass (softwood chips) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce a cellulose-rich solid, and then mechanically treating the cellulose-rich solid to produce lignin-coated nanofibrils. The lignin-coated nanofibrils are present in an aqueous suspension (gel) containing approximately 3 wt% solids.

[0272] The dispersant / dryer is selected to be a copolymer of ethylene and acrylic acid based on the lignin-coated nanofibrils and the selected matrix polymer (polypropylene). A specific dispersant / dryer is Honeywell AClyn® 201A wax (Honeywell Performance Materials and Technologies, Morris Plains, New Jersey, USA), which is a calcium ionomer of an ethylene acrylic acid copolymer in powder form neutralized 47% with calcium.

[0273] The starting nanocellulose dispersion slurry is produced by combining, under mechanical agitation, an aqueous suspension of 2,917 grams of lignin-coated nanofibrils with 88 grams of the above-mentioned dispersion / drying agent. The starting nanocellulose dispersion slurry initially contains approximately 3 wt% nanocellulose (lignin-coated nanofibrils) and approximately 94 wt% water. The starting slurry is dried by a semi-batch process under heat and shear using a Brabender PL200 Plasti-Corder torque rheometer equipped with a Haake Rheomix 3000 mixer, mixing at a mixing blade speed of 100 revolutions per minute (RPM) and a temperature of 120 °C. As water evaporates and the volume in the mixer bowl decreases, slurry is continuously added to the rheometer. The process continues for approximately 90 minutes until all of the slurry is fed and all of the moisture has evaporated from the material, at which point the dry concentrate is removed from the mixer. The processing time and the amount of water that needs to be removed during drying can be significantly reduced, for example, by pre-concentrating the slurry by centrifugation. During the heat mixing, water is evaporated from the nanocellulose gel. When water is removed in the shear mixing, aggregation and self-bonding of the nanocellulose are prevented and the wax phase serves as a spacer between the nanocellulose particles.

[0274] When essentially all of the water has been removed from the starting nanocellulose dispersion concentrate, a nanocellulose dispersion concentrate is obtained that contains approximately 50 wt% nanocellulose (lignin-coated nanofibrils) and approximately 50 wt% dispersion / drying agent. It is preferred to remove all of the water, although it is possible for some residual moisture to remain in the nanocellulose dispersion concentrate. It will also be recognized that other nanocellulose concentrations can be used for the nanocellulose dispersion concentrate.

[0275] The nanocellulose dispersion concentrate obtained above is then ground into a powder in a Bel-Art micro mill. The resulting powder is then dispersed in polypropylene as follows. 4 parts by weight of the nanocellulose dispersion concentrate and 96 parts by weight of a polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) are combined and mixed in a Brabender torque rheometer. The rheometer is operated for 11 minutes at a speed of 40 RPM and a temperature of 150 °C. The resulting nanocellulose-polymer composite is shown in the optical micrograph (magnification 100x) of Figure 3, showing 2 wt% nanocellulose (lignin-coated nanofibrils) uniformly dispersed in polypropylene.

[0276] Example 4: Preparation of Nanocellulose Dispersion Concentrate and Nanocellulose-Polypropylene Composite The lignin-coated nanofibrils are obtained by fractionating lignocellulosic biomass (softwood chips) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce a cellulose-rich solid, and then mechanically treating the cellulose-rich solid to produce lignin-coated nanofibrils. The lignin-coated nanofibrils are present in an aqueous suspension (gel) containing approximately 3 wt% solids.

[0277] The dispersant / drying agent is selected to be a copolymer of ethylene and acrylic acid based on the lignin-coated nanofibrils and the selected matrix polymer (polypropylene). A specific dispersant / drying agent is Honeywell A-C® 540A wax (Honeywell Performance Materials and Technologies, Morris Plains, New Jersey, USA), which is an ethylene acrylic acid copolymer in powder form. Honeywell A-C® 540A wax contains 5 wt% acrylic acid.

[0278] The starting nanocellulose dispersion slurry is produced by combining, under mechanical stirring, an aqueous suspension of 2,917 grams of lignin-coated nanofibrils with 88 grams of the above-mentioned dispersion / drying agent. The starting nanocellulose dispersion slurry initially contains approximately 3 wt% nanocellulose (lignin-coated nanofibrils) and approximately 94 wt% water. The starting slurry is dried by a semi-batch process under heat and shear using a Brabender PL200 Plasti-Corder torque rheometer equipped with a Haake Rheomix 3000 mixer, mixing at a mixing blade speed of 100 revolutions per minute (RPM) and a temperature of 120 °C. As water evaporates and the volume in the mixer bowl decreases, slurry is continuously added to the rheometer. The process continues for approximately 90 minutes until all of the slurry is fed and all of the moisture has evaporated from the material, at which point the dried concentrate is removed from the mixer. The processing time and the amount of water that needs to be removed during drying can be significantly reduced, for example, by pre-concentrating the slurry by centrifugation. During the heat mixing, water is evaporated from the nanocellulose gel. When water is removed in the shear mixing, aggregation and self-bonding of the nanocellulose are prevented, and the wax phase serves as a spacer between the nanocellulose particles.

[0279] When essentially all of the water has been removed from the starting nanocellulose dispersion concentrate, a nanocellulose dispersion concentrate is obtained that contains approximately 50 wt% nanocellulose (lignin-coated nanofibrils) and approximately 50 wt% dispersion / drying agent. It is preferred to remove all of the water, although it is also possible for some residual moisture to remain in the nanocellulose dispersion concentrate. It will also be recognized that other nanocellulose concentrations can be used for the nanocellulose dispersion concentrate.

[0280] The nanocellulose dispersion concentrate obtained above is then ground into a powder in a Bel-Art micromill. The resulting powder is then dispersed in polypropylene as follows. 4 parts by weight of the nanocellulose dispersion concentrate and 96 parts by weight of a polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) are combined and mixed in a Brabender torque rheometer. The rheometer is operated for 11 minutes at a speed of 40 RPM and a temperature of 150 °C. The resulting nanocellulose-polymer composite is shown in the optical micrograph (magnification 100x) of Figure 4, showing 2 wt% nanocellulose (lignin-coated nanofibrils) uniformly dispersed in polypropylene.

[0281] Example 5: Preparation of Nanocellulose Dispersion Concentrate and Nanocellulose-Polypropylene Composite Lignin-coated nanofibrils are obtained by fractionating lignocellulosic biomass (softwood chips) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce a cellulose-rich solid, and then mechanically treating the cellulose-rich solid to produce lignin-coated nanofibrils. The lignin-coated nanofibrils are present in an aqueous suspension (gel) containing approximately 3 wt% solids.

[0282] The dispersant / dryer is selected to be a copolymer of ethylene and acrylic acid based on the lignin-coated nanofibrils and the selected matrix polymer (polypropylene). A specific dispersant / dryer is Honeywell A-C® 580 wax (Honeywell Performance Materials and Technologies, Morris Plains, New Jersey, USA), which is an ethylene acrylic acid copolymer in pellet form. Honeywell A-C® 580 wax contains 10 wt% acrylic acid and has an acid value of 75.

[0283] The starting nanocellulose dispersion slurry is produced by combining, under mechanical stirring, an aqueous suspension of 2,917 grams of lignin-coated nanofibrils with 88 grams of the above-mentioned dispersion / drying agent. The starting nanocellulose dispersion slurry initially contains approximately 3 wt% nanocellulose (lignin-coated nanofibrils) and approximately 94 wt% water. The starting slurry is dried by a semi-batch process under heat and shear using a Brabender PL200 Plasti-Corder torque rheometer equipped with a Haake Rheomix 3000 mixer, mixing at a mixing blade speed of 100 revolutions per minute (RPM) and a temperature of 120 °C. As water evaporates and the volume in the mixer bowl decreases, slurry is continuously added to the rheometer. The process is continued for approximately 90 minutes until all of the slurry is fed and all of the moisture has evaporated from the material, at which point the dried concentrate is removed from the mixer. The processing time and the amount of water that needs to be removed during drying can be significantly reduced, for example, by pre-concentrating the slurry by centrifugation. During the heat mixing, water is evaporated from the nanocellulose gel. When water is removed in the shear mixing, aggregation and self-bonding of the nanocellulose are prevented, and the wax phase serves as a spacer between the nanocellulose particles.

[0284] When essentially all of the water has been removed from the starting nanocellulose dispersion concentrate, a nanocellulose dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanofibrils) and approximately 50 wt% dispersion / drying agent results. Although it is preferred to remove all of the water, it is also possible for some residual moisture to remain in the nanocellulose dispersion concentrate. It will also be recognized that other nanocellulose concentrations can be used for the nanocellulose dispersion concentrate.

[0285] The nanocellulose dispersion concentrate obtained above is then ground into a powder in a Bel-Art micromill. The resulting powder is then dispersed in polypropylene as follows. 4 parts by weight of the nanocellulose dispersion concentrate and 96 parts by weight of a polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) are combined and mixed in a Brabender torque rheometer. The rheometer is operated for 11 minutes at a speed of 40 RPM and a temperature of 150 °C. The resulting nanocellulose-polymer composite is shown in the optical micrograph (magnification 100x) of Figure 5, showing 2 wt% nanocellulose (lignin-coated nanofibrils) uniformly dispersed in polypropylene.

[0286] Example 6: Preparation of Nanocellulose Dispersion Concentrate and Nanocellulose-Polylactic Acid Composite Lignin-coated nanocrystals are obtained by fractionating lignocellulosic biomass (hardwood chips) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce a cellulose-rich solid, and then mechanically treating the cellulose-rich solid to produce lignin-coated nanocrystals. The lignin-coated nanocrystals are present in an aqueous suspension (gel) containing about 6 wt% solids.

[0287] The dispersant / dryer is selected to be a copolymer of ethylene and acrylic acid based on the lignin-coated nanocrystals and the selected matrix polymer (polylactic acid). A specific dispersant / dryer is Honeywell A-C® 540A wax (Honeywell Performance Materials and Technologies, Morris Plains, New Jersey, USA), which is an ethylene acrylic acid copolymer in powder form. Honeywell A-C® 540A wax contains 5 wt% acrylic acid.

[0288] The starting nanocellulose dispersion slurry is produced by combining, under mechanical agitation, an aqueous suspension of 1,458 grams of lignin-coated nanocrystals with 88 grams of the above-mentioned dispersion / drying agent. The starting nanocellulose dispersion slurry initially contains approximately 6 wt% nanocellulose (lignin-coated nanocrystals) and approximately 89 wt% water. The starting slurry is dried by a semi-batch process under heat and shear using a Brabender PL200 Plasti-Corder torque rheometer equipped with a Haake Rheomix 3000 mixer, mixing at a mixing blade speed of 100 revolutions per minute (RPM) and a temperature of 120 °C. As water evaporates and the volume within the mixer bowl decreases, slurry is continuously added to the rheometer. The process is continued for approximately 90 minutes until all of the slurry is fed and all of the moisture has evaporated from the material, at which point the dried concentrate is removed from the mixer. The processing time and the amount of water that needs to be removed during drying can be significantly reduced, for example, by pre-concentrating the slurry by centrifugation. During the heat mixing, water is evaporated from the nanocellulose gel. As water is removed in the shear mixing, aggregation and self-bonding of the nanocellulose are prevented and the wax phase serves as a spacer between the nanocellulose particles.

[0289] When essentially all of the water has been removed from the starting nanocellulose dispersion concentrate, a nanocellulose dispersion concentrate is obtained that contains approximately 50 wt% nanocellulose (lignin-coated nanocrystals) and approximately 50 wt% dispersion / drying agent. It is preferred to remove all of the water, although it is also possible for some residual moisture to remain in the nanocellulose dispersion concentrate. It will also be recognized that other nanocellulose concentrations can be used for the nanocellulose dispersion concentrate.

[0290] The nano-cellulose dispersion concentrate obtained above is then ground into a powder in a Bel-Art micro mill. The resulting powder is then dispersed in polylactic acid as follows. 1 part by weight of the nano-cellulose dispersion concentrate and 99 parts by weight of polylactic acid (INGEO® PLA 4043D, NatureWorks LLC, Minnetonka, Minnesota, USA) are combined and mixed in a Brabender torque rheometer. The rheometer is operated for 11 minutes at a speed of 40 RPM and a temperature of 140 °C. The resulting nano-cellulose-polymer composite is shown in the optical micrograph (magnification 100x) of Figure 6, showing 0.5 wt% nano-cellulose (lignin-coated nano-crystals) uniformly dispersed in polylactic acid.

[0291] Example 7: Preparation of Nano-Cellulose Dispersion Concentrate and Nano-Cellulose-Polylactic Acid Composite Lignin-coated nano-crystals are obtained by fractionating lignocellulosic biomass (hardwood chips) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce a cellulose-rich solid, and then mechanically treating the cellulose-rich solid to produce lignin-coated nano-crystals. The lignin-coated nano-crystals are present in an aqueous suspension (gel) containing approximately 6 wt% solids.

[0292] The dispersant / dryer is selected to be a copolymer of ethylene and acrylic acid based on the lignin-coated nanofibrils and the selected matrix polymer (polylactic acid). A specific dispersant / dryer is Honeywell A-C® 580 wax (Honeywell Performance Materials and Technologies, Morris Plains, New Jersey, USA), which is an ethylene acrylic acid copolymer in pellet form. Honeywell A-C® 580 wax contains 10 wt% acrylic acid and has an acid value of 75.

[0293] The starting nanocellulose dispersion slurry is produced by combining, under mechanical stirring, an aqueous suspension of 1,458 grams of lignin-coated nanocrystals with 88 grams of the above-mentioned dispersion / drying agent. The starting nanocellulose dispersion slurry initially contains approximately 6 wt% nanocellulose (lignin-coated nanocrystals) and approximately 89 wt% water. The starting slurry is dried by a semi-batch process under heat and shear using a Brabender PL200 Plasti-Corder torque rheometer equipped with a Haake Rheomix 3000 mixer, mixing at a mixing blade speed of 100 revolutions per minute (RPM) and a temperature of 120 °C. As water evaporates and the volume in the mixer bowl decreases, slurry is continuously added to the rheometer. The process is continued for approximately 90 minutes until all of the slurry is fed and all of the moisture has evaporated from the material, at which point the dry concentrate is removed from the mixer. The processing time and the amount of water that needs to be removed during drying can be significantly reduced, for example, by pre-concentrating the slurry by centrifugation. During the heat mixing, water is evaporated from the nanocellulose gel. When water is removed in the shear mixing, aggregation and self-bonding of the nanocellulose are prevented, and the wax phase serves as a spacer between the nanocellulose particles.

[0294] When essentially all of the water has been removed from the starting nanocellulose dispersion concentrate, a nanocellulose dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanocrystals) and approximately 50 wt% dispersion / drying agent results. It is preferred to remove all of the water, although it is also possible for some residual moisture to remain in the nanocellulose dispersion concentrate. It will also be recognized that other nanocellulose concentrations can be used for the nanocellulose dispersion concentrate.

[0295] The nanocellulose dispersion concentrate obtained above is then ground into a powder in a Bel-Art micromill. The resulting powder is then dispersed in polylactic acid as follows. 1 part by weight of the nanocellulose dispersion concentrate and 99 parts by weight of polylactic acid (INGEO® PLA 4043D, NatureWorks LLC, Minnetonka, Minnesota, USA) are combined and mixed in a Brabender torque rheometer. The rheometer is operated for 11 minutes at a speed of 40 RPM and a temperature of 140 °C. The resulting nanocellulose-polymer composite is shown in the optical micrograph (magnification 100x) of Figure 7, showing 0.5 wt% nanocellulose (lignin-coated nanocrystals) uniformly dispersed in polylactic acid.

[0296] Example 8: Preparation of a Nanocellulose Dispersion Concentrate for a Non-Aqueous Chemical System Lignin-coated nanocellulose fibrils are obtained by fractionating lignocellulosic biomass (softwood chips) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce a cellulose-rich solid, and then mechanically treating the cellulose-rich solid to produce lignin-coated nanocrystals. The lignin-coated nanocrystals are present in an aqueous suspension (gel) containing about 3 wt% solids.

[0297] The dispersant / drying agent is selected to be an ammonia stearate emulsion which is an ammonium salt of stearic acid. Stearic acid is an 18-carbon chain fatty acid having the chemical formula C 17 H 35 CO2H and is selected for its bifunctionality having a polar head group capable of reacting with nanocellulose and lignin hydroxyl groups and a non-polar chain imparting solubility in organic solvents.

[0298] The starting nanocellulose dispersion slurry is produced by mixing 3889 grams of an aqueous suspension of lignin-coated nanofibrils with 58 grams of an ammonia stearate dispersant / drying agent in the form of an aqueous emulsion. The starting nanocellulose dispersion slurry initially contains approximately 3 wt% nanocellulose (lignin-coated nanofibrils) and approximately 96 wt% water. The starting slurry is dried by a semi-batch process under heat and shear using a Brabender PL200 Plasti-Corder torque rheometer equipped with a Haake Rheomix 3000 mixer at a mixing blade speed of 100 revolutions per minute (RPM) and a temperature of 120 °C for 90 minutes. As water evaporates and the volume in the mixer bowl decreases, slurry is continuously added to the rheometer. The process continues for approximately 90 minutes until all of the slurry is fed and all of the moisture has evaporated from the material, at which point the dry concentrate is removed from the mixer. The processing time and the amount of water that needs to be removed during drying can be significantly reduced, for example, by pre-concentrating the slurry by centrifugation. During the heat mixing, water is evaporated from the nanocellulose gel. When water is removed in the shear mixing, aggregation and self-bonding of the nanocellulose are prevented, and stearic acid (or stearate) serves as a spacer between the nanocellulose particles.

[0299] When essentially all of the water has been removed from the starting nanocellulose dispersion concentrate, a nanocellulose dispersion concentrate is obtained that contains approximately 67 wt% nanocellulose (lignin-coated nanofibrils) and approximately 33 wt% dispersant / drying agent. It is preferred to remove all of the water, although it is possible for some residual moisture to remain in the nanocellulose dispersion concentrate. It will also be recognized that other nanocellulose concentrations can be used for the nanocellulose dispersion concentrate.

[0300] The nanocellulose dispersion concentrate obtained above is then ground in a hammer mill and dispersed in the general plasticizer diisononyl phthalate (DINP) as follows. About 2 parts by weight of the nanocellulose dispersion concentrate and 98 parts by weight of DINP are combined in a vortex mixer for 4 minutes under ambient conditions. The resulting stable thixotropic non-aqueous dispersion of nanocellulose is shown in the optical micrograph (magnification 400x) of Figure 8, showing about 1.3 wt% of nanocellulose (lignin-coated nanofibrils) uniformly dispersed in DINP.

[0301] In this detailed description, multiple embodiments and non-limiting examples of the present invention are referred to regarding ways in which the present invention can be understood and practiced. Other embodiments that do not provide all of the features and advantages recited herein may be utilized without departing from the spirit and scope of the present invention. The present invention encompasses routine experimentation and optimization of the methods and systems described herein. Such modifications and variations are considered to be within the scope of the present invention as defined by the claims.

[0302] All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety as if each individual publication, patent, or patent application was specifically and individually recited herein.

[0303] If the above methods and steps indicate specific events occurring in a specific order, those skilled in the art will recognize that the ordering of the specific steps may be modified and that such modifications are in accordance with variations of the present invention. Further, some of the steps may be implemented not only simultaneously with parallel processes when possible, but also sequentially.

[0304] Accordingly, it is intended that this patent may cover those variations as well, insofar as they exist and are within the spirit of the disclosure or equivalent to the invention found in the claims. The present invention is to be limited only by the claims.

Claims

**Claim 1** (a) from about 5 wt% to about 90 wt% of nanocellulose; and (b) from about 5 wt% to about 95 wt% of a dispersion / drying agent selected to be compatible with said nanocellulose A nanocellulose dispersion concentrate comprising: wherein said dispersion / drying agent is a copolymer of ethylene and maleic anhydride or a copolymer of ethylene and acrylic acid; wherein said nanocellulose dispersion concentrate is in solid form or liquid form; and wherein said nanocellulose dispersion concentrate consists essentially of said nanocellulose, said dispersion / drying agent, and optionally water. Nanocellulose dispersion concentrate. **Claim 2** The nanocellulose dispersion concentrate according to claim 1, wherein said nanocellulose is present at a concentration of from about 10 wt% to about 70 wt% and said dispersion / drying agent is present at a concentration of from about 5 wt% to about 50 wt%. **Claim 3** The nanocellulose dispersion concentrate according to claim 1, wherein the weight ratio of said nanocellulose to said dispersion / drying agent is selected from about 0.5 to about 2. **Claim 4** The nanocellulose dispersion concentrate according to claim 1, wherein said nanocellulose comprises cellulose nanocrystals, cellulose nanofibrils, microfibrillated cellulose, or a combination thereof. **Claim 5** The nanocellulose dispersion concentrate according to claim 1, wherein said nanocellulose comprises lignin-containing nanocellulose. **Claim 6** The nanocellulose dispersion concentrate according to claim 1, wherein said nanocellulose comprises lignin-coated nanocellulose.

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