Nanocellulose-dispersion concentrates and masterbatches, methods of making 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 a nanocellulose-dispersion concentrate comprising nanocellulose and a selected dispersant / drying agent for compatibility with the nanocellulose and with nanocellulose-containing composite products, wherein the dispersant / drying agent is selected from the group consisting of a wax, a polyolefin, an olefin maleic anhydride copolymer, an olefin acrylic acid copolymer, a polyol, a fatty acid, a fatty alcohol, a polyol glyceride, a polydimethylsiloxane, a polydimethylsiloxane alkyl ester, a polyacrylamide, a starch, a cellulose derivative, a microparticle, and combinations or reaction products thereof, and wherein the nanocellulose-dispersion concentrate is in solid form (e.g., a powder) or liquid form. Other variations provide a nanocellulose-dispersion masterbatch (e.g., a pellet) comprising the nanocellulose-dispersion concentrate and a carrier material. Other variations provide a nanocellulose-containing composite comprising the nanocellulose-dispersion masterbatch or concentrate and a matrix material. Methods of making and using the disclosed compositions are described.

Description

[0001] This application is a divisional application of the invention patent application filed on February 28, 2020, with application number 202080017529.8, entitled "Nanocellulose-Dispersion Concentrate and Masterbatch, Method for Manufacturing and Using the Same, and Composite Materials Containing Nanocellulose", the entire contents of which are incorporated herein by reference.

[0002] The parent application is international patent application PCT / US2020 / 020270, which entered the national phase in China and claims priority to U.S. Provisional Patent Application No. 62 / 787,462, filed on January 2, 2019. The aforementioned patent application is hereby incorporated herein by reference. Technical Field

[0003] The present invention generally relates to compositions and methods for dispersing nanocellulose in polymers and other systems. Background Technology

[0004] Nanocellulose has gained attention as a nanostructured material. Nanocellulose is characterized by its biodegradability and environmental sustainability because it is derived from naturally occurring resources, cellulose—the most abundant polymer on Earth. Furthermore, regardless of its social and environmental sustainability, nanocellulose offers significant technological potential for improving the mechanical strength and other properties of composite materials. Nanocellulose is composed of parallel, linear polysaccharide molecules. In addition to its abundance and sustainability, nanocellulose possesses attractive physicochemical properties, such as exceptionally high stiffness and strength.

[0005] Nanocellulose is being developed for a wide range of applications, such as polymer reinforcement, antimicrobial membranes, biodegradable food packaging, printing paper, pigments and inks, paper and paperboard packaging, barrier films, adhesives, biocomposites, wound healing, pharmaceuticals and drug delivery, textiles, water-soluble polymers, building materials, recyclable internal and structural components for the transportation industry, rheology modifiers, low-calorie food additives, cosmetic thickeners, pharmaceutical tablet adhesives, bioactive paper, Pickering stabilizers for emulsions and granules, coating formulations, membranes for optical switches, and detergents.

[0006] However, significant technical challenges exist associated with the widespread use of nanocellulose. In particular, removing water from nanocellulose suspensions to maintain nanoscale dimensions is extremely difficult. In most cases, nanocellulose particles are processed into aqueous suspensions due to their hydrophilic properties and tendency to aggregate during drying. Industrially, there is a need to develop robust dispersions and drying methods that will maintain nanoscale dimensions for applications requiring the dried form of the material. A drier form of nanocellulose also reduces the high transportation costs of diluted aqueous suspensions and expands the number of end-use applications where the amount of water that can be added to the product is limited.

[0007] In the case of both cellulose nanocrystals and cellulose nanofibrils (or microfibrils), the dispersibility of nanocellulose in non-aqueous polymers and other systems remains problematic because they typically require a dried form of nanocellulose for incorporation. Nanocellulose tends to irreversibly self-bind during drying, resulting in large aggregates. These large aggregates often hinder or even destroy the intended property benefits of introducing nanocellulose particles into polymer composites or other systems. For example, well-dispersed nanocellulose particles in a polymer can lead to significant increases in mechanical strength. However, when nanocellulose becomes aggregated, there may be no increase in mechanical strength at all—or worse, large aggregates can lead to stress concentration points that can cause premature failure of polymer components.

[0008] Various drying methods have been attempted to improve the dispersion of nanocellulose in non-aqueous products. These methods typically require extreme measures that have proven difficult to scale up to commercial levels and are therefore uneconomical. Often, these methods are based on lyophilization of nanocellulose, an established laboratory method used to prevent irreversible interparticle bonding in nanocellulose. Lyophilization is neither economical nor scalable for the commercial production of nanocellulose.

[0009] For almost all non-aqueous applications in which nanocellulose is used, improving its dispersion, and therefore the utility and benefits of these applications, has been a major obstacle to the implementation of nanocellulose. Therefore, it has become important to improve the dispersion of nanocellulose using economical methods that make it highly dispersible in polymers and other systems. Economical methods typically require a dry composition containing nanocellulose. The dry form of nanocellulose is particularly important in areas where thermoplastic processing, such as extrusion and injection molding, involves hot-melt processes. During hot-melt processes using non-polar thermoplastics, water is detrimental to satisfactory processing.

[0010] In view of the aforementioned needs in the art, there is a strong need for improved compositions and methods for dispersing and drying nanocellulose, for polymer composites and other systems besides polymers. Summary of the Invention

[0011] Some variations of the present invention provide a nanocellulose dispersion concentrate comprising: (a) Nanocellulose ranging from about 5 wt% to about 90 wt%; and (b) A selected dispersant / drying agent, ranging from about 5 wt% to about 95 wt%, for compatibility with the nanocellulose. The dispersant / 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-glycerides, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products, and the nanocellulose-dispersion concentrate is in solid or liquid form.

[0012] 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 some embodiments, the weight ratio of nanocellulose to dispersant / drying agent is selected from about 0.5 to about 2. The nanocellulose-dispersion concentrate may consist essentially of the nanocellulose and the dispersant / drying agent, i.e., without any other functional components.

[0013] 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.

[0014] In some embodiments, the dispersant / drying agent is a functionalized polyalkylene wax that is functionalized to be compatible with the nanocellulose. For example, the functionalized polyalkylene wax may be a functionalized polyethylene wax, a functionalized polypropylene wax, a functionalized polybutene wax, or a combination thereof. In some 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 from 2 to 1000, such as from 5 to 500.

[0015] In some embodiments, the dispersant / drying agent is a copolymer of (a) one or more C2-C4 olefins and (b) maleic anhydride.

[0016] In some embodiments, the dispersant / drying agent is (a) a copolymer of one or more C2-C4 olefins and (b) acrylic acid.

[0017] 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, or combinations thereof, wherein the polyol is optionally esterified with fatty acids.

[0018] In some embodiments, the dispersant / drying agent comprises an alkyl ester polydimethylsiloxane emulsion.

[0019] In some embodiments, the dispersant / drying agent includes cationic starch, amphoteric starch, thermoplastic starch, or a combination thereof.

[0020] In some embodiments, the dispersant / drying agent comprises microparticles optionally having surface treatments to provide surface charge and / or improve interfacial adhesion, such as silylation of glass fibers. The microparticles may 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 some embodiments, the dispersant / drying agent comprises at least one fatty acid and at least one microparticle.

[0021] The nanocellulose-dispersion concentrate may further contain a liquid solvent, such as a solvent selected from the group consisting of water, C1-C8 alcohols, C2-C8 polyols, and combinations thereof.

[0022] The nanocellulose-dispersion concentrate may further contain one or more elastomers (e.g., natural or synthetic rubber) in concentrations ranging from about 0.1 wt% to about 50 wt%.

[0023] Other variations of the present invention provide a nanocellulose-dispersion masterbatch comprising: (a) Nanocellulose from about 1 wt% to about 75 wt%; (b) A selected dispersant / drying agent, ranging from about 1 wt% to about 89 wt%, for compatibility with the nanocellulose; and (c) From about 10 wt% to about 98 wt% of a carrier material (e.g., a carrier polymer) that is different from the nanocellulose and the dispersant / drying agent. The dispersant / drying agent mentioned above is selected from the group consisting of: waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products. Furthermore, the nanocellulose-dispersion masterbatch is in solid or liquid form.

[0024] 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 some masterbatch embodiments, the weight ratio of the nanocellulose to the dispersant / drying agent is selected from about 0.5 to about 2. The nanocellulose-dispersion masterbatch may consist substantially of the nanocellulose, the dispersant / drying agent, and the carrier material.

[0025] In some masterbatch embodiments, the nanocellulose includes cellulose nanocrystals, cellulose nanofibrils, microfibrillated cellulose, or combinations thereof.

[0026] In some masterbatch embodiments, the nanocellulose includes lignin-containing nanocellulose, such as lignin-coated nanocellulose.

[0027] In some masterbatch embodiments, the dispersant / drying agent is a functionalized polyolefin wax that is functionalized for compatibility with the nanocellulose. For example, the functionalized polyolefin wax may be a functionalized polyethylene wax, a functionalized polypropylene wax, a functionalized polybutene wax, or a combination thereof. In some 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 from 2 to 1000.

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

[0029] In some masterbatch embodiments, the dispersant / drying agent is (a) a copolymer of one or more C2-C4 olefins and (b) acrylic acid.

[0030] In some masterbatch embodiments, the dispersant / 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 fatty acids.

[0031] In some masterbatch embodiments, the dispersant / drying agent comprises alkyl ester polydimethylsiloxane emulsion.

[0032] In some masterbatch embodiments, the dispersant / drying agent includes cationic starch, amphoteric starch, thermoplastic starch, or a combination thereof.

[0033] In some masterbatch embodiments, the dispersant / drying agent comprises microparticles, which optionally have surface treatments to provide surface charge and / or improve interfacial adhesion, such as silylation of glass fibers. The microparticles may 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 some masterbatch embodiments, the dispersant / drying agent comprises at least one fatty acid and at least one microparticle.

[0034] The dispersant / drying agent may also be selected to be compatible with the carrier material of the masterbatch.

[0035] The carrier material may be a carrier polymer or another type of material. When the carrier material is a polymer or includes a polymer, the polymer may be selected from the group consisting of: polyolefins, polyols, polyamides, polylactide, polystyrene, polycarbonate, polyethylene terephthalate, and combinations thereof.

[0036] In a preferred embodiment of the nanocellulose-dispersion masterbatch, the masterbatch is in solid or powder form.

[0037] Other variations of the present invention provide a nanocellulose-polymer composite product comprising: (a) Nanocellulose from about 0.05 wt% to about 10 wt%; (b) A dispersant / drying agent selected for compatibility with the nanocellulose and the nanocellulose-polymer composite product, ranging from about 0.05 wt% to about 10 wt%, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products thereof; (c) A selected carrier polymer, ranging from about 0.1 wt% to about 10 wt%, for compatibility with the nanocellulose and the dispersant / drying agent; and (d) Matrix polymers ranging from about 50 wt% to about 99.8 wt%.

[0038] In some embodiments of the composite material product, the nanocellulose is present in the nanocellulose-polymer composite material product at a concentration of about 0.1 wt% to about 5 wt%. In some embodiments of the composite material product, the weight ratio of the nanocellulose to the dispersant / drying agent is selected from about 0.5 to about 2. The nanocellulose-polymer composite material product may substantially consist of the nanocellulose, the dispersant / drying agent, the carrier polymer, and the matrix polymer.

[0039] In some embodiments of the composite material product, the nanocellulose includes cellulose nanocrystals, cellulose nanofibrils, microfibrillated cellulose, or combinations thereof.

[0040] In some embodiments of the composite material product, the nanocellulose includes lignin-containing nanocellulose, such as lignin-coated nanocellulose.

[0041] In some embodiments of the composite material product, the dispersant / drying agent is a functionalized polyolefin wax that is compatible with the nanocellulose and optionally with the nanocellulose-polymer composite material product. For example, the functionalized polyolefin wax may be a functionalized polyethylene wax, a functionalized polypropylene wax, a functionalized polybutene wax, or a combination thereof. In some embodiments of the composite material product, the dispersant / drying agent is a low molecular weight oligomer or polymer of ethylene or functionalized ethylene, having a number-average degree of polymerization from 2 to 1000.

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

[0043] In some embodiments of the composite material product, the dispersant / drying agent is (a) a copolymer of one or more C2-C4 olefins and (b) acrylic acid.

[0044] In some embodiments of the composite material product, the dispersant / drying agent comprises a polyol selected from ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerol, butanediol, polybutylene glycol, or combinations thereof, wherein the polyol is optionally esterified with fatty acids.

[0045] In some embodiments of the composite material product, the dispersant / drying agent comprises alkyl ester polydimethylsiloxane emulsion.

[0046] In some embodiments of the composite material product, the dispersant / drying agent includes cationic starch, amphoteric starch, thermoplastic starch, or a combination thereof.

[0047] In some embodiments of the composite material product, the dispersant / drying agent comprises microparticles having surface treatments to provide surface charge and / or improve interfacial adhesion, such as silylation of glass fibers. The microparticles may 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 some embodiments, the dispersant / drying agent comprises at least one fatty acid and at least one microparticle.

[0048] In some embodiments of the composite material product, the dispersant / drying agent is also selected to be compatible with the carrier polymer, the matrix polymer, or both.

[0049] The carrier polymer may be selected from the group consisting of: polyolefins, polyols, polyamides, polylactide, polystyrene, polycarbonate, 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 compared to the matrix polymer.

[0050] In various nanocellulose-polymer composite products, the matrix polymer is selected from the group consisting of: polyolefins, polyols, polyesters, polyamides, polylactide, polystyrene, polycarbonate, polyacrylate, polystyrene, styrene rubber, polyurethane, polyurea, poly(amide-enamine), polyanhydride, polyhydroxyalkanoate, poly(alkene dicarboxylate), silicone, carbon polymers, and combinations or copolymers thereof.

[0051] Other variations of the present invention provide a nanocellulose-polymer composite product comprising: (a) Nanocellulose from about 0.05 wt% to about 15 wt%; (b) A selected dispersant / drying agent, from about 0.05 wt% to about 15 wt%, selected for compatibility with the nanocellulose and the nanocellulose-polymer composite product, wherein the dispersant / 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-glycerides, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products; and (c) Matrix polymers ranging from about 50 wt% to about 99.9 wt%.

[0052] In some embodiments, a carrier polymer is not present, such as when the above-described nanocellulose-dispersion concentrate is directly incorporated into the matrix polymer without using a masterbatch.

[0053] 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%, such as from about 0.5 wt% to about 2 wt%. The nanocellulose-polymer composite product may consist essentially of the nanocellulose, the dispersant / drying agent, and the matrix polymer. The options for nanocellulose, the dispersant / drying agent, and the matrix polymer are the same as those summarized above for the components in the nanocellulose-polymer composite product containing a carrier polymer.

[0054] Other variations of the invention provide a composite material product containing nanocellulose, comprising: (a) Nanocellulose from about 0.05 wt% to about 10 wt%; (b) A dispersant / drying agent selected for compatibility with the nanocellulose and the composite product containing the nanocellulose, ranging from about 0.05 wt% to about 10 wt%, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products thereof; (c) A selected carrier material, ranging from about 0.1 wt% to about 10 wt%, for compatibility with the nanocellulose and the dispersant / drying agent; and (d) Matrix material from about 50 wt% to about 99.8 wt%.

[0055] Other variations of the present invention provide a composite material product containing nanocellulose, comprising: (a) Nanocellulose from about 0.05 wt% to about 15 wt%; (b) A selected dispersant / drying agent, from about 0.05 wt% to about 15 wt%, selected for compatibility with the nanocellulose and the composite product containing the nanocellulose, wherein the dispersant / 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-glycerides, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products; and (c) Matrix material from about 50 wt% to about 99.9 wt%.

[0056] Some variations provide a method for producing nanocellulose dispersion concentrates (such as the concentrates disclosed above), the method comprising: Provides nanocellulose gels containing nanocellulose and water; Select a dispersant / drying agent compatible with the nanocellulose, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products. Mix the nanocellulose gel and the dispersant / drying agent; At least a portion of the water is removed during or after the mixing step to produce a nanocellulose dispersion concentrate. Optionally, the nanocellulose-dispersion concentrate is milled to produce a powder; and The nanocellulose-dispersion concentrate is recovered in solid or liquid form.

[0057] In some embodiments, the step of removing at least a portion of the water includes high-shear mixing accompanied by heating to a temperature of at least 50°C.

[0058] 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 may be, for example, a carrier polymer.

[0059] In some embodiments, the method further includes combining the nanocellulose-dispersion masterbatch with a matrix material to form a composite material product containing nanocellulose.

[0060] The matrix material may be a matrix polymer. For example, the matrix polymer may be selected from the group consisting of: polyolefins, polyols, polyesters, polyamides, polylactide, polystyrene, polycarbonate, polyacrylate, polystyrene, natural rubber, synthetic rubber, styrene-based rubber, polyurethane, polyurea, poly(amide-enamine), polyanhydride, polyhydroxyalkanoate, poly(olefin dicarboxylate), silicone, carbon polymers, and combinations or copolymers thereof.

[0061] Alternatively or additionally, the matrix material may be a material other than a polymer, such as materials selected from the group consisting of: paper, paperboard, fiber and wood composites (e.g., particleboard 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.

[0062] The drying step (removing at least a portion of the water) to form the concentrate can be performed at the same location or at a different location than the optional steps for manufacturing the masterbatch. The drying step can also be performed at the same location or at a different location than the step of combining the nanocellulose-dispersion masterbatch or concentrate with the matrix material.

[0063] In some embodiments, the method further includes combining the nanocellulose-dispersion concentrate directly (without via masterbatch) with a matrix material to form a composite material product containing nanocellulose.

[0064] When a nanocellulose dispersion concentrate is added directly to a matrix material, the matrix material may be a matrix polymer, such as a polymer selected from the group consisting of: polyolefins, polyols, polyesters, polyamides, polylactide, polystyrene, polycarbonate, polyacrylate, polystyrene, styrene-based rubbers, natural rubber, synthetic rubber, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyhydroxyalkanoates, poly(olefin dicarboxylate), silicones, carbon polymers, and combinations or copolymers thereof.

[0065] Alternatively or additionally, the matrix material may 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, cementing materials, microparticles, ceramics, metals, metal alloys, glass, and combinations thereof.

[0066] Some variations provide a method for producing nanocellulose dispersion masterbatches (such as the masterbatches disclosed above), the method comprising: Provides nanocellulose gels containing nanocellulose and water; Select a dispersant / drying agent compatible with the nanocellulose, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products. Mix the nanocellulose gel and the dispersant / drying agent; At least a portion of the water is removed during or after the mixing step to produce a nanocellulose dispersion concentrate. Optionally, the nanocellulose-dispersion concentrate is milled to produce a concentrate powder; During the mixing of the nanocellulose gel and the dispersant / drying agent, and / or during the removal of at least a portion of the water, and / or after the removal of at least a portion of the water (thus producing nanocellulose-dispersion masterbatch), and / or while (if performed) milling the nanocellulose-dispersion concentrate to produce concentrate powder, and / or after milling (if performed) the nanocellulose-dispersion concentrate to produce concentrate powder, a carrier polymer (or other carrier material) is introduced into the nanocellulose-dispersion concentrate to produce nanocellulose-dispersion masterbatch; Optionally, the nanocellulose-dispersion masterbatch is milled to produce masterbatch powder; and The nanocellulose-dispersion masterbatch is preferably recycled in solid form.

[0067] Some variations provide a method for producing nanocellulose-polymer composite products (such as the composite products disclosed above), the method comprising: Provides nanocellulose gels containing nanocellulose and water; Select a dispersant / drying agent compatible with the nanocellulose and the nanocellulose-polymer composite product, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products; Mix the nanocellulose gel and the dispersant / drying agent; At least a portion of the water is removed during or after the mixing step to produce a nanocellulose dispersion concentrate. Optionally, the nanocellulose-dispersion concentrate is milled to produce a concentrate powder; During the mixing of the nanocellulose gel and the dispersant / drying agent, and / or during the removal of at least a portion of the water, and / or after the removal of at least a portion of the water (thus producing nanocellulose-dispersion masterbatch), and / or while (if performed) milling the nanocellulose-dispersion concentrate to produce concentrate powder, and / or after milling (if performed) the nanocellulose-dispersion concentrate to produce concentrate powder, a carrier polymer is introduced into the nanocellulose-dispersion concentrate to produce nanocellulose-dispersion masterbatch; Optionally, the nanocellulose-dispersion masterbatch is milled to produce masterbatch powder; The nanocellulose-dispersion masterbatch is mixed with a matrix polymer, and the combined materials are mechanically and / or thermally processed to produce a nanocellulose-polymer composite product; and The nanocellulose-polymer composite product is recycled.

[0068] Some variations provide a method for producing carrier-free cellulose nanocomposite products, the method comprising: Provides nanocellulose gels containing nanocellulose and water; Select a dispersant / drying agent compatible with the nanocellulose and the nanocellulose-polymer composite product, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products; Mix the nanocellulose gel and the dispersant / drying agent; At least a portion of the water is removed during or after the mixing step to produce a nanocellulose dispersion concentrate. Optionally, the nanocellulose-dispersion concentrate is milled to produce a concentrate powder; The nanocellulose-dispersion concentrate is mixed with a matrix polymer, and the combined materials are mechanically and / or thermally processed to produce a nanocellulose-polymer composite product; and The nanocellulose-polymer composite product is recycled. Attached Figure Description

[0069] Figure 1The image is an optical micrograph (100× magnification) of the nanocellulose-polymer composite material of Example 1 using a dispersant / drying agent, showing 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0070] Figure 2 The image is an optical micrograph (100× magnification) of the nanocellulose-polymer composite material of Example 2 using a dispersant / drying agent, showing 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0071] Figure 3 The image is an optical micrograph (100× magnification) of the nanocellulose-polymer composite material of Example 3 using a dispersant / drying agent, showing 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0072] Figure 4 The image is an optical micrograph (100× magnification) of the nanocellulose-polymer composite material of Example 4 using a dispersant / drying agent, showing 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0073] Figure 5 The image is an optical micrograph (100× magnification) of the nanocellulose-polymer composite material of Example 5 using a dispersant / drying agent, showing 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0074] Figure 6 The image is an optical micrograph (100× magnification) of the nanocellulose-polymer composite material of Example 6 using a dispersant / drying agent, showing 0.5 wt% nanocellulose (lignin-coated nanocrystals) uniformly dispersed in polylactide.

[0075] Figure 7 The image shown is an optical micrograph (100× magnification) of the nanocellulose-polymer composite material of Example 7 using a dispersant / drying agent, showing 0.5 wt% nanocellulose (lignin-coated nanocrystals) uniformly dispersed in polylactide.

[0076] Figure 8 The image is an optical micrograph (400× magnification) of the nanocellulose-containing composite material of Example 8 using a dispersant / drying agent, showing 1.3 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in diisononyl phthalate.

[0077] Figure 9This is an optical micrograph (100× magnification) of 2 wt% lignin-coated nanofibers dispersed in water, produced as is, never dried, and never concentrated.

[0078] Figure 10 This is an optical micrograph (100× magnification) of 2 wt% lignin-coated nanocrystals dispersed in water as is, never dried, and never concentrated.

[0079] Figure 11 This is an exemplary optical micrograph (100× magnification) showing poor nanocellulose dispersion (significant particle aggregation) of 2 wt% nanocellulose (lignin-coated nanofibers) in diisononyl phthalate, wherein the nanocellulose has been dried without a dispersant / drying agent.

[0080] Figure 12 These are exemplary flowcharts depicting the methods and principles of the present invention in some embodiments. Detailed Implementation

[0081] This description enables those skilled in the art to make and use the invention, and describes several embodiments, modifications, variations, alternatives, and uses of the invention. These and other embodiments, features, and advantages of the invention will become more apparent to those skilled in the art when referenced in the following detailed description of the invention in conjunction with any of the accompanying drawings.

[0082] As used in this specification and the appended 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 pertains. Unless otherwise indicated, all component numerical values ​​and ranges based on percentages are weight percentages. All ranges of numerical values ​​or conditions are intended to cover any particular value contained within that range, rounded to any suitable decimal point.

[0083] Unless otherwise specified, all numerical values ​​of expression parameters, reaction conditions, component concentrations, etc., used in this specification and claims should be understood to be modified by the term "about" in all cases. Therefore, unless stated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximate values, which may vary at least depending on the specific analytical technique.

[0084] The term "comprising," synonymous with "including," "containing," or "characterized in," is inclusive or open-ended and does not exclude additional, unlisted elements or method steps. "Comprising" is a specialized term used in claims language to mean that the specified claim element is essential, but other claim elements may be added and still constitute a concept within the scope of the claims.

[0085] As used herein, the phrase “consisting of” excludes any element, step, or component not specified in the claims. When the phrase “consisting of” (or variations thereof) appears in a clause of the body of a claim rather than immediately following the preamble, the phrase limits only the element set forth in that clause; it does not exclude other elements from the claim in general. As used herein, the phrase “substantially constitutes” limits the scope of the claim to the specified element or method step, plus those that do not substantially affect the basis of the claimed subject matter and one or more novel features.

[0086] Regarding the terms “comprising,” “consisting of,” and “substantially consisting of,” when one of these three terms is used herein, the currently disclosed and claimed subject matter may include the use of any of the other two terms. Therefore, in some embodiments not otherwise explicitly enumerated, any instance of “comprising” may be replaced by “consisting of,” or alternatively by “substantially consisting of.”

[0087] In some variations, the present invention is based on the selection and incorporation of dispersants / drying agents for nanocellulose. As explained in the background section, it is generally desirable for composite products to incorporate unique nanocellulose particles and prevent these particles from agglomerating (aggregating) during production or use. Nanocellulose is typically available as an aqueous dispersion, such as from cellulosic biomass or produced via bacterial synthesis. In diluted aqueous dispersions, nanocellulose particles remain non-aggregated or reversibly aggregated. For most polymer systems, the aqueous dispersion itself cannot be introduced into the polymer matrix—water must first be removed. Even for aqueous systems, additive products containing as little water as possible are preferred to minimize product transportation costs, spoilage, and the amount of water introduced into the product system with the additive for the end use. For example, it is generally unacceptable to introduce excessive water with the additive into the product system, such that the product must subsequently be dehydrated or dried beyond normal levels.

[0088] As used herein, a "dispersant / drying agent" is a chemical, or combination of chemicals, that prevents irreversible aggregation of nanocellulose during drying or dehydration. The dispersants / drying agents disclosed herein are selected to maintain the distinct nanocellulose particles by preventing aggregation between nanocellulose particles during the drying or dehydration (removal of water) of the aqueous dispersion. In the absence of an effective dispersant / drying agent, irreversible aggregation between nanocellulose particles has been observed by heating and drying to as low as 20 wt%–30 wt% solids slurry. When nanocellulose is incorporated into composite products, the dispersant / drying agent also maintains the distinct nanocellulose particles and effectively and readily releases individual nanocellulose particles during the formulation of the composite product, maximizing the effectiveness of the nanocellulose. To reduce or prevent the self-aggregation of nanocellulose during drying, the dispersant / drying agent can be selected to sufficiently interact with the surface of the nanocellulose and / or distribute uniformly among the nanocellulose particles, thereby reducing or preventing nanocellulose aggregation.

[0089] Exemplary embodiments of the invention will now be described. These embodiments are not intended to limit the scope of the claimed invention. The order of steps may be changed, some steps may be omitted, and / or other steps may be added. References to first step, second step, etc., herein are for illustrative purposes only. Furthermore, it should be understood that all references to “embodiments” are non-limiting and are considered alternatives to any other disclosed embodiments unless the context clearly indicates otherwise.

[0090] Some variations of the present invention provide a nanocellulose dispersion concentrate comprising: (a) Nanocellulose ranging from about 5 wt% to about 90 wt%; and (b) A selected dispersant / drying agent, ranging from about 5 wt% to about 95 wt%, for compatibility with the nanocellulose. The dispersant / drying agent mentioned above is selected from the group consisting of: waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products. Furthermore, the nanocellulose-dispersion concentrate is in solid or liquid form.

[0091] 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 at most about 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 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 at most about 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, or 95 wt%, including all intermediate ranges.

[0092] In some embodiments, the total amount of nanocellulose and dispersant / drying agent is about, at least about, or at most about 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 99 wt%, or 100 wt%. The nanocellulose-dispersion concentrate may consist essentially of the nanocellulose and the dispersant / drying agent, i.e., without any other functional components.

[0093] 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 at most 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.

[0094] Nanocellulose can include cellulose nanocrystals, cellulose nanofibrils, or a combination of cellulose nanocrystals and cellulose nanofibrils. In some embodiments, the nanocellulose includes lignin-containing nanocellulose, such as lignin-coated nanocellulose. Various types of nanocellulose are described in more detail below.

[0095] The nanocellulose dispersion concentrate may be completely dry or may contain water at a concentration from about 0.1 wt% to about 70 wt%. In various embodiments, the nanocellulose dispersion concentrate contains about, or at most about, about 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 60 wt%, or 70 wt% water, including all intermediate ranges.

[0096] The nanocellulose dispersion concentrate may further contain 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.

[0097] In some embodiments, the nanocellulose-dispersion concentrate further comprises 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%, such as about 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%.

[0098] Nanocellulose dispersion concentrates are compositions containing nanocellulose that are redispersible in a matrix of interest (e.g., a polymer). The redispersibility of nanocellulose dispersion concentrates can be tested or demonstrated in other systems such as water, propanol, or other liquids or solids that are not necessarily polymers.

[0099] In some embodiments, the nanocellulose-dispersion concentrate is redispersed in an aqueous solution. In a typical example of such embodiments, water is removed from the initial nanocellulose gel for the purpose of transporting the nanocellulose (to avoid the weight of the transported water), and different amounts of water are added back at the point of use. Preferably, the nanocellulose can be readily dispersed in water to form a nanocellulose gel without the need for homogenization or other mechanical refining (beyond standard industrial mixing). For example, the nanocellulose-dispersion concentrate powder can be very easily broken down into individual nanoparticles in water under tank stirring (e.g., for 30 minutes).

[0100] Nanocellulose dispersion concentrates can be provided in pre-packaged form. Pre-packaged forms can be in small containers, tubes, vials, wide-mouth bottles, bags, bulk bags, or drums, for example, in pre-packaged materials that may be glass, plastic, coated paper, etc. In some embodiments, nanocellulose dispersion concentrates are provided in powder form, such as dry powder. In some embodiments, nanocellulose dispersion concentrates are part of a kit that includes the pre-packaged nanocellulose dispersion concentrate and instructions for use tailored to a specific masterbatch or composite system.

[0101] In this specification, "nanocellulose-dispersion concentrate" refers to a composition containing at least nanocellulose and a dispersant / drying agent. "Nanocellulose-dispersion masterbatch" refers to a composition containing at least nanocellulose, a dispersant / drying agent, and a carrier material. As will be understood from this specification, the nanocellulose-dispersion concentrate can be used directly to produce composite products containing nanocellulose. In some embodiments of the production of composite products containing nanocellulose, the use of a masterbatch is advantageous.

[0102] In this specification, all references to “matrix polymer” are to be construed as exemplary references to “matrix material.” Similarly, all references to “carrier polymer” are to be construed as exemplary references to “carrier material.” While many embodiments involving polymers have been described, this patent application is expressly not limited to the use of nanocellulose-dispersion concentrates in polymer systems.

[0103] Other variations of the present invention provide a nanocellulose-dispersion masterbatch comprising: (a) Nanocellulose from about 1 wt% to about 75 wt%; (b) A selected dispersant / drying agent, ranging from about 1 wt% to about 89 wt%, for compatibility with the nanocellulose; and (c) A carrier polymer, different from the nanocellulose and the dispersant / drying agent, from about 10 wt% to about 98 wt%. The dispersant / drying agent mentioned above is selected from the group consisting of: waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products. Furthermore, the nanocellulose-dispersion masterbatch is in solid or liquid form.

[0104] In some masterbatch embodiments, 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, nanocellulose is present at a concentration of about, at least about, or at most about 2 wt%, 3 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 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 at most about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, or 85 wt%, including all intermediate ranges.

[0105] In some masterbatch embodiments, the total amount of nanocellulose and dispersant / drying agent is about, at least about, or at most about 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 99 wt%, or 100 wt%. The nanocellulose-dispersion masterbatch may consist essentially of nanocellulose, dispersant / drying agent, and carrier polymer, i.e., no other functional components are present.

[0106] In some masterbatch embodiments, the weight ratio of nanocellulose to dispersant / drying agent is selected from about 0.5 to about 2. In different embodiments, the weight ratio of nanocellulose to dispersant / drying agent is about, at least about, or at most 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.

[0107] In some masterbatch embodiments, the weight ratio of the carrier polymer to nanocellulose is selected from about 1 to about 100, such as about, at least about, or at most about 2, 5, 10, 20, 50, or 80, including all intermediate ranges.

[0108] The dispersant / drying agent can also be selected for compatibility with the carrier polymer of the masterbatch. Alternatively, the carrier polymer can be selected for compatibility with the selected dispersant / drying agent.

[0109] The carrier polymer may be selected from the group consisting of: polyolefins, polyols, polyamides, polylactide, polystyrene, polycarbonate, polyethylene terephthalate, and combinations thereof.

[0110] In a preferred embodiment of the nanocellulose-dispersion masterbatch, the masterbatch is in solid or powder form. The powder can be granulated into spheres, cylinders, plates, or other geometric shapes.

[0111] In other embodiments, the nanocellulose dispersion masterbatch is in liquid form or in a masterbatch solvent (such as water, C1-C8 alcohol, C2-C8 polyol, or a combination thereof). In some embodiments, the masterbatch is in powder form but contains water or other solvents absorbed in the solid.

[0112] Nanocellulose dispersion masterbatches can be provided in pre-packaged form. Pre-packaged forms may be in small containers, tubes, vials, wide-mouth bottles, or bags, for example, in pre-packaged materials that may be glass, plastic, coated paper, etc. In some embodiments, the nanocellulose dispersion masterbatch is provided in powder form, such as dry powder. In other embodiments, the nanocellulose dispersion masterbatch is granulated or compressed into various geometries, such as spheres, beads, rods, cylinders, plates, etc. In some embodiments, the nanocellulose dispersion masterbatch is part of a kit that includes pre-packaged nanocellulose dispersion masterbatch and instructions for use tailored to a specific composite system.

[0113] Other variations of the present invention provide a nanocellulose-polymer composite product comprising: (a) Nanocellulose from about 0.05 wt% to about 10 wt%; (b) A dispersant / drying agent selected for compatibility with the nanocellulose and the nanocellulose-polymer composite product, ranging from about 0.05 wt% to about 10 wt%, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products thereof; (c) A selected carrier polymer, ranging from about 0.1 wt% to about 10 wt%, for compatibility with the nanocellulose and the dispersant / drying agent; and (d) Matrix polymers ranging from about 50 wt% to about 99.8 wt%.

[0114] In some embodiments of the composite material product, the nanocellulose is present in the nanocellulose-polymer composite material product at a concentration of about 0.1 wt% to about 5 wt%. The dispersant / drying agent may be present at a concentration of about 0.1 wt% to about 5 wt%. In different composite material products, the nanocellulose is present at a concentration of about, at least about, or at most about 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 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 at most about 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, including all intermediate ranges.

[0115] In some composite products, the total amount of nanocellulose and dispersant / drying agent is about, at least about, or at most about 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt%. Nanocellulose-polymer composite products can consist essentially of nanocellulose, dispersant / drying agent, carrier polymer, and matrix polymer, i.e., no other functional components are present.

[0116] In some composite products, the weight ratio of nanocellulose to dispersant / drying agent is selected from about 0.5 to about 2. In different composite products, the weight ratio of nanocellulose to dispersant / drying agent is about, at least about, or at most 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.

[0117] In some composite products, the weight ratio of the carrier polymer to nanocellulose is selected from about 1 to about 100, such as about, at least about, or at most about 2, 5, 10, 20, 50, or 80, including all intermediate ranges.

[0118] In some composite products, the weight ratio of matrix polymer to nanocellulose is selected from about 5 to about 2000, such as about, at least about, or at most about 5, 10, 50, 100, 200, 500, 1000, 1500, or 2000, including all intermediate ranges.

[0119] In some composite products, 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 at most about 2, 10, 50, 100, 500, 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, or 9,000, including all intermediate ranges.

[0120] 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 about, at least about, or at most about 5, 10, 50, 100, 500, 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, or 9,000, including all intermediate ranges.

[0121] In some embodiments of the composite material product, the dispersant / drying agent is also selected for compatibility with the carrier polymer, the matrix polymer, or both. Alternatively, or additionally, the carrier polymer may be selected for compatibility with the dispersant / drying agent and / or the matrix polymer.

[0122] The carrier polymer can be selected from the group consisting of: polyolefins, polyols, polyamides, polylactide, 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 compared to the matrix polymer. It is also possible to replace the carrier polymer with a carrier material that is not a polymer. For example, the carrier material can be an organic liquid, an organic solid, an inorganic liquid, an inorganic solid, or a combination thereof.

[0123] In various nanocellulose-polymer composite products, the matrix polymer is selected from the group consisting of: polyolefins, polyols, polyesters, polyamides, polylactide, polystyrene, polycarbonates, polyacrylates, polystyrene, styrene-based rubbers, natural rubbers, synthetic rubbers, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyhydroxyalkanoates, poly(olefin dicarboxylate), silicones, carbon polymers, and combinations or copolymers thereof.

[0124] Other variations of the present invention provide a nanocellulose-polymer composite product comprising: (a) Nanocellulose from about 0.05 wt% to about 15 wt%; (b) A selected dispersant / drying agent, from about 0.05 wt% to about 15 wt%, selected for compatibility with the nanocellulose and the nanocellulose-polymer composite product, wherein the dispersant / 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-glycerides, polydimethylsiloxanes, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products; and (c) Matrix polymers ranging from about 50 wt% to about 99.9 wt%.

[0125] In some embodiments, the carrier polymer is absent, such as when the nanocellulose dispersion concentrate is incorporated directly into the matrix polymer without using a masterbatch. In some embodiments, it is also possible to selectively remove the carrier polymer from the composite product, such as by hydrolysis or melting.

[0126] 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%, such as from about 0.5 wt% to about 2 wt%. The nanocellulose-polymer composite product may consist essentially of the nanocellulose, the dispersant / drying agent, and the matrix polymer.

[0127] In some composite products that do not contain a carrier polymer, the weight ratio of the matrix polymer to nanocellulose is selected from about 2 to about 2000, such as about, at least about, or at most about 5, 10, 50, 100, 200, 500, 1000, 1500, or 2000, including all intermediate ranges.

[0128] 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 at most about 2, 5, 10, 50, 100, 500, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, or 9000, including all intermediate ranges.

[0129] The dispersant / drying agent is selected based on its compatibility with the selected nanocellulose and the end-use product. In some embodiments, the dispersant / drying agent contains one or more chemical components and / or functional groups capable of hydrogen bonding with polar groups present in the nanocellulose. The polar groups of nanocellulose include at least -OH and to some extent -O-; other polar groups may be present if functionalized nanocellulose is used. In other embodiments, the dispersant / drying agent is not necessarily capable of hydrogen bonding with polar groups present in the nanocellulose. In these or other embodiments, the dispersant / drying agent contains a component that acts as a particulate spacer. The particulate spacer not only physically separates the nanocellulose particles but also does not repel the nanocellulose phase. This is important because repulsion of nanocellulose leads to self-association and aggregation of nanocellulose, resulting in irreversible binding during drying. Instead, the particulate spacer within the dispersant / drying agent prevents nanocellulose from associating in this manner, thereby reducing or preventing irreversible aggregation.

[0130] Dispersants / desiccantes can also be selected based on economics (cost or availability), the ability to manufacture them in situ as a byproduct, or their environmental sustainability. In some embodiments, dispersants / desiccantes are bio-based, biodegradable, and / or compostable.

[0131] In some embodiments, the dispersant / drying agent is a functionalized polyolefin wax that is functionalized for compatibility with the nanocellulose and optionally with nanocellulose-polymer composite products. As used herein, a "functionalized" hydrogen-containing compound is a compound in which at least one hydrogen atom is replaced by a functional group. For example, -H can be replaced by -OH, -COOH, =O, or other oxygen-containing functional groups. In some embodiments, -H can be replaced by oxygen-free functional groups (such as, for example, metals, halogens, nitrogen, sulfur, or groups containing these components).

[0132] The functionalized polyolefin wax may be a functionalized polyethylene wax, a functionalized polypropylene wax, a functionalized polybutene wax, or a combination thereof. In some embodiments, the dispersant / drying agent is a low molecular weight oligomer or polymer of ethylene or functionalized ethylene. When functionalized ethylene is used, each repeating unit may 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 may be from 2 to 1000, such as from 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.

[0133] In some embodiments, the dispersant / drying agent 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 olefin can be a functionalized olefin, such as a functionalized ethylene. Maleic anhydride is an organic compound having the formula C2H2(CO)2O and is the anhydride of maleic acid. For the purposes of this document, polymers of maleic acid or salts thereof are also considered polymers of maleic anhydride. Maleic anhydride can be produced from 5-hydroxymethylfurfural, which itself can be derived from, for example, biomass (glucose dehydration). C2-C4 olefins can also be produced from biomass, such as via the dehydration of alcohols produced through the fermentation of sugars.

[0134] Copolymers of C2-C4 olefins and maleic anhydride can be block copolymers, alternating copolymers, random copolymers, or combinations thereof. When the olefin is ethylene, for example, the copolymer can be poly(ethylene-alternating-maleic anhydride) and / or poly(ethylene-grafted-maleic anhydride). A graft copolymer is a type of copolymer in which one or more blocks of the homopolymer are grafted as branches onto the main chain, meaning it is a branched copolymer having one or more side chains of the homopolymer attached to the main chain backbone. Thus, poly(ethylene-grafted-maleic anhydride) can also be considered a polymer of functionalized ethylene in which ethylene is functionalized with maleic acid or maleic anhydride. This type of copolymer can also be called maleicated polyethylene.

[0135] In some embodiments, the dispersant / drying agent is (a) a copolymer of 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 olefin may be a functionalized olefin, such as a functionalized ethylene. Acrylic acid is an organic compound having the formula CH2=CHCOOH. For the purposes of this document, polymers of acrylic acid or salts thereof are also considered polymers of acrylic anhydrides.

[0136] Copolymers of C2-C4 olefins and acrylic acid can be block copolymers, alternating copolymers, random copolymers, or combinations thereof. Typically, acrylic acid polymerizes across its double bonds, similar to ethylene polymerization (e.g., in free radical copolymerization), to obtain copolymers that can be considered as graft copolymers or polymers of functionalized ethylene in which ethylene is functionalized by acrylic acid.

[0137] In some embodiments, the dispersant / drying agent comprises a polyol selected from the group consisting of ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerol, butylene glycol, polybutylene glycol, butanediol, or combinations thereof. In some embodiments, the polyol is esterified with a fatty acid such as stearate.

[0138] In some embodiments, the dispersant / drying agent is or comprises glycerol, or is dissolved in glycerol as a solvent. Glycerol has a high boiling point (approximately 290°C) and three hydroxyl groups (one OH group for each carbon atom). As the nanocellulose is dried, glycerol can insert itself between the nanocellulose particles by forming hydrogen bonds, which blocks the formation of H-bonds and the aggregation that would otherwise occur between the nanocellulose particles. The high boiling point of glycerol is advantageous for use in dry powders. These powders can be dispersed in hydrophobic polymer matrices such as polylactide (PLA). When PLA is extruded, the glycerol between the nanocellulose particles can act as a plasticizer, or the glycerol can be removed during processing by vacuum, or a combination thereof.

[0139] The dispersant / 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. For example, a relatively high vapor pressure at elevated temperatures may be beneficial when it is desired to remove the dispersant / drying agent during final polymer compounding. 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, such as at least 1.0 OH groups per carbon atom. The OH groups prevent irreversible bonding between nanoparticles during drying. The polar additive can be organic or inorganic.

[0140] In some embodiments, the dispersant / drying agent comprises fatty acids. Fatty acids are carboxylic acids having long aliphatic chains, whether saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain with an even number of carbon atoms (from 4 to 28). The fatty acids described herein may be selected, for example, caprylic acid, capric acid, lauric acid, stearic acid, arachidic acid, benzyl acid, tetracosanoic acid, ceric acid, or combinations thereof. Unsaturated and / or branched fatty acids may be used.

[0141] In some embodiments, the dispersant / drying agent comprises a fatty alcohol. A fatty alcohol is a long-chain alcohol, which is a straight-chain primary alcohol ranging from 4 to 26 carbon atoms. Exemplary fatty alcohols include lauryl alcohol (dodecanoyl alcohol), stearyl alcohol, and oleyl alcohol. Fatty alcohols can be oily liquids (for smaller carbon numbers) or waxy solids. Fatty alcohols typically have an even number of carbon atoms and a single alcohol group (-OH) attached to a terminal carbon. Some are unsaturated and some are branched. Unsaturated and / or branched fatty alcohols can be used. Fatty alcohols having an odd number of carbon atoms can be used. Ethylene can be oligomerized and the oligomer subjected to hydroformylation to produce an odd-numbered aldehyde, which can then be hydrogenated. For example, hydroformylation of 1-decene gives C 11 alcohol.

[0142] In some embodiments, the dispersant / drying agent comprises a siloxane-based additive. The siloxane-based additive may comprise a siloxane or polysiloxane material having one or more functional groups selected from the group consisting of: methyl, C2-C... 24 Alkyl groups, epoxides, hydroxyl groups, amino groups, carboxyl groups, acrylates, and combinations thereof. An exemplary siloxane-based additive is polydimethylsiloxane.

[0143] Siloxane-based additives preferably provide both hydrophobic and hydrophilic portions. Typically, the hydrophobic and hydrophilic portions are located at opposite ends of the molecule or polymer chain. Siloxane-based additives are preferably present as an emulsion in water. In some embodiments, the dispersant / drying agent comprises an alkyl ester polydimethylsiloxane emulsion. During the drying of nanocellulose with the emulsion, the nanocellulose surrounds oil phase droplets during drying, and is then dragged into the oil phase when water is removed. In some embodiments, the siloxane-based additive acts as a hydrogen bonding blocking agent during drying.

[0144] In some embodiments, the dispersant / drying agent includes starch, such as cationic starch, amphoteric starch, thermoplastic starch, or combinations thereof.

[0145] Cationic starch carries a positive charge, which may be desirable when nanocellulose particles have a small amount of negative surface charge. Exemplary cationic starches include quaternary ammonium cationic starch and tertiary amino cationic starch.

[0146] Amphoteric starch is a modified starch containing both positively and negatively charged substituents. An example amphoteric starch contains a quaternary ammonium cationic group and a phosphate group as an anionic group.

[0147] Thermoplastic starch is starch that has been plasticized by relatively low levels (e.g., 15 wt%–30 wt%) of molecules capable of hydrogen bonding with the hydroxyl groups of starch. Starch plasticizers can be water, polyols (e.g., glycerol), pentaerythritol, sugar alcohols (e.g., sorbitol), poly(ethylene oxide), poly(propylene oxide), nonionic surfactants, anionic surfactants, or combinations thereof.

[0148] In some embodiments, the dispersant / drying agent comprises microparticles. The microparticles may 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 nanotubes, graphene, or combinations thereof. In some embodiments, the microparticles have a surface charge, preferably a positive charge. Known surface treatments can be used to impart a surface charge to the microparticles, such as treatment with acidic solutions at low pH. Other surface treatments can be applied to the microparticles, such as silylation, to improve interfacial adhesion.

[0149] In some embodiments, the dispersant / drying agent comprises at least one fatty acid and at least one particulate. The fatty acid and particulate may be present in a non-reactive form or may react with each other in the dispersant / drying agent. In these embodiments, for example, the dispersant / drying agent may comprise (a) a fatty acid selected from caprylic acid, capric acid, lauric acid, stearic acid, arachidic acid, benzyl acid, tetracosanoic acid, ceric 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. An exemplary dispersant / drying agent having both fatty acids and particulates includes talc and stearic acid. Another exemplary dispersant / drying agent having both fatty acids and particulates includes calcium carbonate and stearic acid.

[0150] In various embodiments, the dispersant / drying agent comprises an ionomer that associates with a metal cation (such as calcium or zinc) to form a neutral salt. In various embodiments, the dispersant / drying agent comprises a positively charged component that associates with anion to form a neutral salt (such as surface-charged microparticles or cationic starch).

[0151] The dispersant / drying agent should be selected based on the properties of the nanocellulose to be dispersed and dried. In particular, the hydrophilicity of the nanocellulose will at least partially determine the suitability of the dispersant / drying agent. Composition, particle size, melting point, and other factors may also be considered when selecting a suitable dispersant / drying agent.

[0152] Hydrophilic molecules, or portions thereof, are those whose interactions with water and other polar substances are thermodynamically more favorable than their interactions with oils or other hydrophobic solvents. Hydrophilic molecules are typically charge-polarized and capable of hydrogen bonding. On the other hand, hydrophobic molecules are not attracted to water or other polar molecules. Cellulose nanoparticles are typically highly hydrophilic, but not always. In some embodiments, such as lignin-containing cellulose nanoparticles, they are relatively hydrophobic. Even in lignin-containing cellulose nanoparticles, some hydrophilic properties are generally present because lignin itself is not purely hydrophobic.

[0153] In a preferred embodiment, the hydrophilicity of the selected dispersant / drying agent (or a portion thereof) is matched or similar to that of the nanocellulose, such that they are associated and the dispersant / drying agent separates the regions of the nanocellulose.

[0154] In some embodiments, the hydrophilicity of the dispersant / drying agent is also selected, at least in part, based on the hydrophilicity of the carrier polymer in the masterbatch and / or the matrix polymer (or other matrix material) in the final composite material. The dispersant / drying agent may be designed to have both hydrophilic and hydrophobic components, such as at both ends of the molecule. In such embodiments, for example, the hydrophilic end attaches to the surface of the nanocellulose, while the hydrophobic end grips the hydrophobic polymer during compounding.

[0155] In some embodiments, the dispersant / drying agent is selected based on its melting point. In these embodiments, the dispersant / drying agent is at least partially melted during the drying of the nanocellulose-dispersion concentrate. As the dried nanocellulose-dispersion concentrate is cooled, the dispersant / drying agent returns to the solid phase in which the nanocellulose is uniformly dispersed. As an example, polyethylene waxes (including functionalized variants) have melting points in the range of approximately 100°C–150°C.

[0156] Besides enhancing the dispersion of nanocellulose, dispersants / drying agents can have other functions. For example, in some embodiments, dispersants / drying agents can act as compatibilizers (between the matrix polymer and nanocellulose), plasticizers, density modifiers, viscosity modifiers, or toughness modifiers. Dispersants / drying agents can also provide auxiliary properties, such as color or texture, to the final composite product or masterbatch.

[0157] In some variations, a technical solution is provided that includes the following steps (see also...). Figure 12 (Flowchart). First, a matrix material is selected based on engineering and product needs. Note that the principles of this invention can be applied to polymers or non-polymers as matrix materials. Second, a nanocellulose material is selected such that the nanocellulose is expected to improve certain properties of the matrix material (e.g., mechanical strength, viscosity, etc.). Third, a dispersant / drying agent is selected based on the selected nanocellulose material, such that the dispersant / drying agent is compatible with the nanocellulose. Fourth, a nanocellulose-dispersion concentrate is prepared by combining the dispersant / drying agent with the nanocellulose and optionally other components. Fifth, a nanocellulose-dispersion masterbatch is prepared 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 material product (e.g., a polymer-nanocellulose composite). In some embodiments, the step of preparing the nanocellulose-dispersion masterbatch may be omitted, in which case the nanocellulose-dispersion concentrate is directly combined with the selected matrix material to produce a composite material product.

[0158] Some variations provide a method for producing nanocellulose dispersion concentrates, the method comprising: Provides nanocellulose gels containing nanocellulose and water; Select a dispersant / drying agent compatible with the nanocellulose, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products. Mix the nanocellulose gel and the dispersant / drying agent; At least a portion of the water is removed during or after the mixing step to produce a nanocellulose dispersion concentrate. Optionally, the nanocellulose-dispersion concentrate is milled to produce a powder; and The nanocellulose-dispersion concentrate is recovered in solid or liquid form.

[0159] The water in nanocellulose gels can be at least partially replaced by another polar solvent. Typically, nanocellulose is prepared in an aqueous solution, but this is not strictly necessary. Biomass fractionation processes for producing nanocellulose can, in principle, use polar solvents (such as glycerol or ethanol) instead of water, or any other solvent besides water. Therefore, while most such disclosures concern water as the primary or sole polar solvent in the starting nanocellulose gel, it will be understood that one or more polar solvents other than water can be utilized.

[0160] Some variations provide a method for producing nanocellulose-dispersion masterbatch, the method comprising: Provides nanocellulose gels containing nanocellulose and water; Select a dispersant / drying agent compatible with the nanocellulose, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products. Mix the nanocellulose gel and the dispersant / drying agent; At least a portion of the water is removed (i.e., dried) during or after the mixing step to produce a nanocellulose-dispersion concentrate; Optionally, the nanocellulose-dispersion concentrate is milled to produce a concentrate powder; During the mixing of the nanocellulose gel and the dispersant / drying agent, and / or during the removal of at least a portion of the water, and / or after the removal of at least a portion of the water (thus producing nanocellulose-dispersion masterbatch), and / or while (if performed) milling the nanocellulose-dispersion concentrate to produce concentrate powder, and / or after milling (if performed) the nanocellulose-dispersion concentrate to produce concentrate powder, a carrier polymer is introduced into the nanocellulose-dispersion concentrate to produce nanocellulose-dispersion masterbatch; Optionally, the nanocellulose-dispersion masterbatch is milled to produce masterbatch powder; and The nanocellulose-dispersion masterbatch is preferably recycled in solid form.

[0161] Some variations provide a method for producing nanocellulose-polymer composite products, the method comprising: Provides nanocellulose gels containing nanocellulose and water; Select a dispersant / drying agent compatible with the nanocellulose and the nanocellulose-polymer composite product, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products; Mix the nanocellulose gel and the dispersant / drying agent; At least a portion of the water is removed (i.e., dried) during or after the mixing step to produce a nanocellulose-dispersion concentrate; Optionally, the nanocellulose-dispersion concentrate is milled to produce a concentrate powder; During the mixing of the nanocellulose gel and the dispersant / drying agent, and / or during the removal of at least a portion of the water, and / or after the removal of at least a portion of the water (thus producing nanocellulose-dispersion masterbatch), and / or while (if performed) milling the nanocellulose-dispersion concentrate to produce concentrate powder, and / or after milling (if performed) the nanocellulose-dispersion concentrate to produce concentrate powder, a carrier polymer is introduced into the nanocellulose-dispersion concentrate to produce nanocellulose-dispersion masterbatch; Optionally, the nanocellulose-dispersion masterbatch is milled to produce masterbatch powder; The nanocellulose-dispersion masterbatch is mixed with a matrix polymer, and the combined materials are mechanically and / or thermally processed to produce a nanocellulose-polymer composite product; and The nanocellulose-polymer composite product is recycled.

[0162] Some variations provide a method for producing carrier-free cellulose nanocomposite products, the method comprising: Provides nanocellulose gels containing nanocellulose and water; Select a dispersant / drying agent compatible with the nanocellulose and the nanocellulose-polymer composite product, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products; Mix the nanocellulose gel and the dispersant / drying agent; At least a portion of the water is removed (i.e., dried) during or after the mixing step to produce a nanocellulose-dispersion concentrate; Optionally, the nanocellulose-dispersion concentrate is milled to produce a concentrate powder; The nanocellulose-dispersion concentrate is mixed with a matrix polymer, and the combined materials are mechanically and / or thermally processed to produce a nanocellulose-polymer composite product; and The nanocellulose-polymer composite product is recycled.

[0163] In some variations, a method for producing nanocellulose dispersion concentrates includes: Provides nanocellulose gels containing nanocellulose and water; Select a dispersant / drying agent compatible with the nanocellulose, wherein the dispersant / 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-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products. Mix the nanocellulose gel and the dispersant / drying agent; At least a portion of the water is removed during or after the mixing step to produce a nanocellulose dispersion concentrate. Optionally, the nanocellulose-dispersion concentrate is milled to produce a powder; and The nanocellulose-dispersion concentrate is recovered in solid or liquid form.

[0164] In some embodiments, the step of removing at least a portion of the water includes high-shear mixing accompanied by heating to a temperature of at least 50°C.

[0165] 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 may be, for example, a carrier polymer.

[0166] In some embodiments, the method further includes combining the nanocellulose-dispersion masterbatch with a matrix material to form a composite material product containing nanocellulose.

[0167] The matrix material may be a matrix polymer. For example, the matrix polymer may be selected from the group consisting of: polyolefins, polyols, polyesters, polyamides, polylactide, polystyrene, polycarbonates, polyacrylates, polystyrene, styrene-based rubbers, natural rubber, synthetic rubber, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyhydroxyalkanoates, poly(olefin dicarboxylate), silicones, carbon polymers, and combinations or copolymers thereof.

[0168] Alternatively, or additionally, the matrix material can be a material other than a polymer, such as materials selected from the group consisting of: paper, paperboard, fiber and wood composites (e.g., particleboard and molded pulp products), emulsions, hydrogels, carbon, organic solids, inorganic solids, oils, organic liquids, inorganic liquids, cementing materials (e.g., concrete or cement), minerals, ceramics, metals, metal alloys, glass, and combinations thereof. For example, non-polymer matrix materials can be adhesive matrices, battery electrode matrices, bio-ink matrices, or electronic ink matrices.

[0169] In embodiments where the masterbatch is manufactured, the drying step for producing the concentrate may be performed at the same location or at a different location than the step for manufacturing the masterbatch. Furthermore, the drying step for producing the concentrate may be performed at the same location or at a different location than the step for manufacturing the final composite material (combining the matrix material with the masterbatch or concentrate).

[0170] In some embodiments, the method further includes combining the nanocellulose-dispersion concentrate directly (without via masterbatch) with a matrix material to form a composite material product containing nanocellulose.

[0171] When a nanocellulose dispersion concentrate is added directly to a matrix material, the matrix material may be a matrix polymer, such as a polymer selected from the group consisting of: polyolefins, polyols, polyesters, polyamides, polylactide, polystyrene, polycarbonate, polyacrylate, polystyrene, styrene-based rubbers, natural rubber, synthetic rubber, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyhydroxyalkanoates, poly(olefin dicarboxylate), silicones, carbon polymers, and combinations or copolymers thereof.

[0172] Alternatively or additionally, the matrix material may 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, cementing materials, minerals, ceramics, metals, metal alloys, glass, and combinations thereof.

[0173] The drying step (removing at least a portion of the water) to form the concentrate can be performed in the same location as the step of directly combining the nanocellulose-dispersion concentrate with the matrix material. Alternatively, or additionally, the drying step to form the concentrate can be performed in a different location than the step of combining the nanocellulose-dispersion concentrate with the matrix material.

[0174] In any of the methods disclosed herein, the order of the steps can vary in any logical order. Furthermore, the location of the steps can vary, such that the entire method resides at one or more sites. For example, a nanocellulose-dispersion masterbatch can be manufactured at a first location and transported to a second location for polymer compounding to produce a polymer composite material, and then transported itself to a third location to manufacture the final commercial product.

[0175] All methods disclosed herein can be performed in batch, continuous, or semi-continuous manner. The feedstock can vary widely, including laboratory-scale, pilot-scale, small-scale plant-scale, and commercial-scale operations.

[0176] The drying step of the nanocellulose gel with the dispersant / drying agent is preferably carried out under mechanical forces such as shear force, centrifugal force, compression force, or a combination thereof. Typically, shear force is used in the drying step. High-shear mixing techniques under heating include, but are not limited to, homogenization, σ-blade mixing, rotor-stator mixing, static online mixing, and extrusion. In some embodiments, a melt rheometer can be used to achieve high-shear mixing. Preferably, the high-shear mixing apparatus is configured to allow the continuous or intermittent release of vapors, such as water vapor, during drying. Note that the step of mixing the nanocellulose gel and the dispersant / drying agent can be configured as a premixing step prior to drying. The premixing step does not necessarily need to be high-shear mixing.

[0177] Furthermore, the drying step is preferably carried out at elevated temperatures and optionally under vacuum, such as 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 may be based in part on the melting point of the dispersant / drying agent. The elevated temperature may be achieved by heating and / or by heat that generates self-mixing forces. The drying step may be carried out for a suitable time, such as from about 1 minute to about 4 hours.

[0178] If mixing is carried out at least below the boiling point of water under mixing pressure, and if water vapor can be released from the mixing apparatus, the step of removing at least a portion of the water (referred to herein as "drying," regardless of the mechanism or apparatus) can be performed during mixing. Water removal can be accomplished solely by evaporation, but is not mandatory. For example, the amount of water that needs to be removed during processing time and during drying can be significantly reduced by pre-concentration via centrifugation, filter press, or belt press. In some embodiments, sufficient water removal is achieved via centrifugation or filtration without evaporation. Typically, water (or other polar solvents) is allowed to evaporate from the nanocellulose gel. When water is removed simultaneously with mixing, the dispersant / drying agent prevents the nanocellulose from agglomerating and irreversibly binding itself.

[0179] Nanocellulose dispersion concentrate may contain water at a concentration of about, or at most 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., about 0.5 wt% to 1.5 wt% water or about 0.1 wt% to 7 wt% water).

[0180] The characteristics of nanocellulose lie in the presence of both unbound and bound moisture. Therefore, the choice of drying method, equipment, and configuration of operating parameters can be tailored to the ratio of unbound to bound moisture in the feed material to the drying system. All other factors are the same for non-lignin-containing nanocellulose, but this ratio is typically different for lignin-containing nanocellulose.

[0181] If carried out, the milling to produce concentrated powder or masterbatch powder can typically be performed using conventional equipment such as (but not limited to) hammer mills, ball mills, jet mills, impact crushers, pulverizers, cage mills, or grinding mills. The milling step can be selected based on the drying technology and the properties of the material to be milled.

[0182] Nanocellulose dispersion masterbatch may contain water at a moisture concentration of 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 range.

[0183] Some or all of the dispersant / drying agent (and any solvent) can be removed during compounding or after the manufacture of the composite material. For example, in the case of glycerol as a dispersant / drying agent or solvent, glycerol can be removed from the extruder outlet. As another example, in the case of wax as a dispersant / drying agent, the wax can be selectively melted out of the composite material. Preferably, when the dispersant / drying agent is removed, the matrix polymer and / or carrier polymer fill the space left by the dispersant / drying agent, so that the nanocellulose remains non-aggregated even after some or all of the dispersant / drying agent is removed.

[0184] This invention supplies a variety of nanocellulose materials. Nanocellulose can be produced by decomposing biomass into submicron cellulose nanofibers or nanocrystals using chemical, mechanical, or a combination of chemical and mechanical methods. Other methods for providing nanocellulose, such as bacterial nanocellulose and tunicate-derived nanocellulose, are also available.

[0185] Typically, the production of nanocellulose occurs in two main stages. The first stage is the purification of the biomass to remove most of the non-cellulose components, such as lignin, hemicellulose, extracts, and inorganic contaminants. This stage is typically carried out through conventional pulping and bleaching. To produce cellulose nanofibers, the second stage typically requires mechanical refining of the purified biomass fibers (with or without chemical or enzymatic treatment to reduce the amount of mechanical energy required). For cellulose nanocrystals, the second stage typically requires acidic hydrolysis of the purified fibers followed by high-shear mechanical treatment.

[0186] Nanocellulose can be obtained by fractionating lignocellulose biomass in the presence of an acid catalyst, a solvent for lignin, and water to produce a cellulose-rich solid, followed by mechanical treatment of 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, lignin sulfonic acid, and combinations thereof.

[0187] Nanocellulose can be obtained by the AVAP® lignocellulose biomass fractionation method. It has been found that very high crystallinity can be generated and maintained during the formation of nanofibers or nanocrystals without the need for enzymatic treatment or a separate acid treatment step to hydrolyze amorphous cellulose. High crystallinity can be interpreted as mechanically strong fibers or good physical reinforcing properties, which is advantageous for applications such as composites, reinforcing polymers, and high-strength spun fibers and textiles.

[0188] In some embodiments, nanocellulose comprises hydrophobic nanocellulose. In these or other embodiments, nanocellulose comprises hydrophilic nanocellulose. In some embodiments, nanocellulose comprises lignin-containing cellulose nanocrystals (e.g., lignin-coated cellulose nanocrystals) and / or lignin-containing cellulose nanofibrils (e.g., lignin-coated cellulose nanofibrils).

[0189] In some embodiments, the nanocellulose material is at least partially hydrophobic by depositing at least some of the lignin onto the surface of a cellulose-rich solid (nanocellulose precursor). In these or other embodiments, the nanocellulose material is at least partially hydrophobic by depositing at least some of the lignin onto the surface of the nanocellulose material followed by mechanical refining.

[0190] 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 method can be controlled such that a portion of the dissolved lignin is intentionally deposited back onto the surface of the cellulose-rich solid, thereby making the cellulose-rich solid at least partially hydrophobic.

[0191] Methodological conditions that favor lignin deposition onto the fibers can be employed, such as extended time and / or temperature, or reduced concentration of the solvent used for lignin. Alternatively, or additionally, one or more washing steps can be adapted to deposit at least some of the lignin dissolved during the initial fractionation. One approach is to use water instead of an aqueous solution and solvent for washing. Because lignin is generally insoluble in water, it will begin to precipitate. Optionally, other conditions (such as pH and temperature) can be varied during fractionation, washing, or other steps to optimize the amount of lignin deposited on the surface. Optionally, methods for producing hydrophobic nanocellulose materials may further include chemically modifying the lignin to increase the hydrophobicity of the nanocellulose materials.

[0192] Alternatively, or additionally, nanocellulose can be obtained by fractionating lignocellulosic biomass, optionally with a fractionation catalyst (e.g., acetic acid), in the presence of steam or hot water to obtain a cellulose-rich solid, followed by mechanical refining of the cellulose-rich solid to produce nanocellulose. These steps can be collectively referred to as hydrothermal-mechanical processing. The reaction solution used for fractionation can consist essentially of steam or hot water. Note that "steam or hot water" refers to water that will be in one or more thermodynamically determined phases at a given temperature and pressure. The temperature used for fractionation can be from about 120°C to about 220°C, such as about 150°C–200°C. Water can be in the form of steam, superheated steam, supersaturated steam, or pressurized liquid water. In some embodiments, the fractionation step is performed with a residence time ranging from about 1 minute to about 60 minutes, such as about 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 5 minutes, 7.5 minutes, 10 minutes, 12.5 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, or 55 minutes.

[0193] In embodiments employing hydrothermal-mechanical processing, the cellulose-rich solid typically contains a significant concentration of lignin. Therefore, these embodiments can be advantageous when hydrophobic nanocellulose is desired. Hydrothermal-mechanical processing can produce nanocellulose, which can be referred to as nano-lignocellulose due to its high lignin content. Nano-lignocellulose may contain, based on extremely dry, ash-free, and acetyl-free, cellulose nanofibrils, cellulose microfibrils, or combinations thereof, from about 35 wt% to about 80 wt%, lignin from about 15 wt% to about 45 wt%, and hemicellulose from about 5 wt% to about 20 wt%. Some of the lignin present may coat the nanocellulose particles, while the remainder of the lignin remains within the nanocellulose particles.

[0194] Nanocellulose is preferably obtained from lignocellulose biomass. As used herein, "lignocellulose biomass" means any material containing cellulose and lignin. Lignocellulose biomass may also contain hemicellulose. A mixture of one or more types of biomass may be used. In some embodiments, the biomass feedstock comprises a lignocellulose component (such as one described above) other than a sucrose-containing component (e.g., sugarcane or energy sugarcane) and / or a starch component (e.g., corn, wheat, rice, etc.). Different moisture levels may be associated with the starting biomass. The biomass feedstock does not need to be, but can be, relatively dry. Typically, biomass is in the form of particles or fragments, but the particle size of the starting biomass is not critical.

[0195] Biomass feedstocks used to manufacture nanocellulose can be selected from hardwoods, softwoods, forest residues, eucalyptus, industrial waste, pulp and paper waste, consumer waste, or combinations thereof. Some embodiments use agricultural residues that comprise lignocellulosic biomass associated with food crops, annual forage grasses, energy crops, or other annually renewable feedstocks. Exemplary agricultural residues include, but are not limited to, corn stalks, corn fiber, wheat stalks, bagasse, sugarcane stalks, rice stalks, oat stalks, barley stalks, miscanthus, energy sugarcane stalks / residues, or combinations thereof.

[0196] Other sources of nanocellulose include bacterial nanocellulose, nanocellulose derived from tunicates, pulp treated with sulfuric acid, pulp treated with 2,2,6,6-tetramethylpiperidine-1-oxy radicals (TEMPO), or pulp treated with cellulase. In some embodiments, the nanocellulose used herein is not bacterial nanocellulose, is not derived from tunicates, is not obtained from sulfuric acid hydrolysis, is not obtained from TEMPO, and / or is not obtained via enzymatic hydrolysis of lignocellulosic biomass or cellulose.

[0197] As anticipated herein, “nanocellulose” is broadly defined to include a range of cellulose materials, including but not limited to microfibrillated cellulose, nanofibrillated cellulose, microcrystalline cellulose, nanocrystalline cellulose, and micronized or fibrillated dissolving pulps. In some embodiments, nanocellulose comprises particles having at least one length dimension (e.g., diameter) at the nanoscale. In some embodiments, nanocellulose comprises particles with an average size greater than 1 micrometer, such as for some microfibrillated cellulose.

[0198] "Nanofibrillated cellulose" or equivalently "cellulose nanofibrils" refers to cellulose fibers or regions containing nano-sized particles or fibers, or both micrometer-sized and nanometer-sized particles or fibers. "Nanocrystalline cellulose" or equivalently "cellulose nanocrystals" refers to cellulose particles, regions, or crystals containing nanometer-sized structural domains, or both micrometer-sized and nanometer-sized structural domains. "Micrometer-sized" includes 1 μm to 100 μm and "nano-sized" includes 0.01 nm to 1000 nm (1 μm). Larger structural domains (including long fibers) may also be present in either of these materials.

[0199] The specific size and shape of cellulose nanofibers can range from nanometers to micrometers in width and / or length. Cellulose nanofibers typically have dimensions of 5 nm–20 nm in width and 500 nm–5000 nm in length, and contain both amorphous and crystalline domains of cellulose. Cellulose nanocrystals typically have widths of 3 nm–8 nm and lengths of 100 nm–500 nm, and are predominantly crystalline. While these ranges and dimensions are typical, this invention covers all cellulose nanomaterials, regardless of particle shape or size.

[0200] Some embodiments employ blends of nanocellulose crystals and fibrils. The blends of nanocellulose crystals and fibrils may contain from 1% to 99% nanocellulose crystals and from 99% to 1% nanocellulose fibrils. In various embodiments, the 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 by weight) nanocellulose crystals, wherein the remainder is nanocellulose fibrils.

[0201] Some embodiments employ blends of cellulose nanofibrils and microfibrils. The blends of cellulose nanofibrils and cellulose microfibrils may contain from 1% to 99% cellulose nanofibrils and from 99% to 1% cellulose microfibrils, respectively. In various embodiments, the blends of cellulose nanofibrils and microfibrils contain 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 98% (all by weight) cellulose nanofibrils, with the remainder being cellulose microfibrils.

[0202] Because nanocellulose fibrils are much larger than nanocellulose crystals, a characteristic of nanocellulose blends is the existence of a wide range of particle sizes. For example, the width of nanocellulose crystals can vary from about 2 nanometers to about 10 nanometers, or from about 3 micrometers to about 6 micrometers. For example, the length of nanocellulose crystals can vary from about 50 nanometers to about 500 nanometers, or from about 100 nanometers to about 350 nanometers. For example, the width of nanocellulose fibrils can vary from about 5 nanometers to about 100 nanometers, or from about 10 micrometers to about 50 micrometers. For example, the length of nanocellulose fibrils can vary from about 200 nanometers to about 10 micrometers, or from about 400 micrometers to about 3 micrometers. The average width of nanocellulose particles in the blend can vary from about 3 nanometers to about 50 nanometers, such as from about 5 nanometers to about 30 nanometers. The average length of nanocellulose particles in the blend can vary from about 50 nanometers to about 5 micrometers, such as from about 100 nanometers to about 2 micrometers.

[0203] In some variations, one method for producing nanocellulose includes: (a) Providing lignocellulose biomass feedstock; (b) Fractionating the feedstock in the presence of acid, a solvent for lignin, and water to produce a cellulose-rich solid and a liquid containing hemicellulose and lignin. (c) Mechanically processing cellulose-rich solids to form cellulose fibrils and / or cellulose crystals, thereby producing nanocellulose materials with a crystallinity of at least 60% (i.e., cellulose crystallinity); and (d) Recycling nanocellulose materials.

[0204] In some embodiments, the acid is selected from the group consisting of sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, lignin sulfonic acid, and combinations thereof. In a specific embodiment, the acid is sulfur dioxide.

[0205] In some embodiments, during step (c), the cellulose-rich solids are processed using a total mechanical energy of less than about 5000 kWh / ton of cellulose-rich solids, such as less than about 4000, 3000, 2000, or 1000 kWh / ton of cellulose-rich solids. Energy consumption can be measured in any other suitable unit. Measuring the current flowing from the motor driving the mechanical processing device with an ammeter is one way to obtain an estimate of the total mechanical energy.

[0206] The mechanical treatment in step (c) may employ one or more known techniques, such as, but not limited to, milling, grinding, beating, ultrasonication, or any other means to form or release nanofibrils and / or nanocrystals in cellulose. Essentially, any type of milling machine or device that physically separates fibers can be used. Such milling machines are well-known in industry and include, but are not limited to, Wally beaters, single-disc refiners, double-disc refiners, conical refiners (including wide-angle and narrow-angle), cylindrical refiners, homogenizers, microfluidizers, and other similar milling or grinding devices. See, for example, Smook, Handbook for Pulp&Paper Technologists [Pulp and Paper Technology Handbook], Tappi Publishing, 1992; and Hubbe et al., “Cellulose Nanocomposites: A Review”. BioResources [ Biological resources ] 3(3), 929-980 (2008).

[0207] The degree of mechanical treatment can be monitored during the process by any of several means. Certain optical instruments can provide continuous data on fiber length distribution and particle size percentage, either of which can be used to define the endpoint of the mechanical treatment step. Time, temperature, and pressure can be varied during the mechanical treatment. For example, in some embodiments, ultrasonic treatment at ambient temperature and pressure can be used for durations ranging from approximately 5 minutes to 2 hours.

[0208] In some embodiments, a portion of the cellulose-rich solid is converted into nanofibrils, while the remaining cellulose-rich solid is not fibrillated. In different embodiments, approximately 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or substantially all of the cellulose-rich solid is fibrillated into nanofibrils.

[0209] In some embodiments, a portion of the nanofibers are converted into nanocrystals, while the remaining nanofibers are not converted into nanocrystals. In different embodiments, approximately 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or substantially all of the nanofibers are converted into nanocrystals. During the drying process, a small amount of nanocrystals may clump together and form nanofibers.

[0210] After mechanical processing, nanocellulose materials can be classified by particle size. A portion of the material can be subjected to a separate process (such as enzymatic hydrolysis) to produce glucose. Such materials may, for example, have good crystallinity, but may not have the desired particle size or degree of polymerization.

[0211] Step (c) may further include treating the cellulose-rich solid with one or more enzymes or with one or more acids. When acids are used, these acids may be selected from the group consisting of sulfur dioxide, sulfurous acid, lignin sulfonic acid, acetic acid, formic acid, and combinations thereof. Acids associated with hemicellulose (such as acetic acid or uronic acid) may be used alone or in combination with other acids. Additionally, step (c) may include treating the cellulose-rich solid with heat. In some embodiments, step (c) does not employ any enzymes or acids.

[0212] In step (c), when an acid is used, the acid can be a strong acid, such as sulfuric acid, nitric acid, or phosphoric acid. A weaker acid can be used at more stringent temperatures and / or times. An enzyme that hydrolyzes cellulose (i.e., cellulase) and possibly hemicellulose (i.e., has hemicellulase activity) can be used in step (c) in sequence before or after acidic hydrolysis.

[0213] In some embodiments, the method includes enzymatically treating a cellulose-rich solid to hydrolyze amorphous cellulose. In other embodiments, or sequentially before or after enzymatic treatment, the method may include acid treatment of the cellulose-rich solid to hydrolyze amorphous cellulose.

[0214] In some embodiments, the method further includes enzymatic treatment of nanocrystalline cellulose. In other embodiments, or sequentially before or after enzymatic treatment, the method further includes acid treatment of nanocrystalline cellulose.

[0215] If desired, enzymatic treatment can be employed before or, if possible, concurrently with mechanical treatment. However, in a preferred embodiment, enzymatic treatment to hydrolyze amorphous cellulose or to weaken the fiber wall structure before separating nanofibers is not necessary.

[0216] Cellulose nanofibrils can be recovered after mechanical processing. The separation of cellulose nanofibrils and / or nanocrystals can be accomplished using devices capable of breaking down the ultrastructure of cell walls while preserving the integrity of the nanofibrils. For example, a homogenizer can be used. In some embodiments, aggregated cellulose fibrils with component fibrils having a width in the range of 1-100 nm are recovered, wherein the fibrils are not yet completely separated from each other.

[0217] The method may further include bleaching the cellulose-rich solid before 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 may be used, including enzymatic bleaching.

[0218] Optionally, the method further includes hydrolyzing amorphous cellulose to glucose in step (b) and / or step (c), recovering the glucose, and fermenting the glucose into a fermentation product. Optionally, the method further includes recovering, fermenting, or further treating hemicellulose sugars derived from hemicellulose. Optionally, the method further includes recovering, burning, or further treating lignin.

[0219] Nanocellulose materials may include or consist essentially of nanofibrillated cellulose. Nanocellulose materials may include or consist essentially of nanocrystalline cellulose. In some embodiments, nanocellulose materials may include or consist essentially of nanofibrillated cellulose and nanocrystalline cellulose.

[0220] 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 higher. 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 higher. Crystallinity can be measured using any known technique. For example, X-ray diffraction and solid-state... 13 C14 nuclear magnetic resonance.

[0221] In some embodiments, the nanocellulose material is characterized by an average degree of polymerization 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 from about 300 to about 700, or from about 150 to about 250. When in the form of nanocrystals, the nanocellulose material may have a degree of polymerization of less than 100, such as about 75, 50, 25, or 10. Some materials may have a degree of polymerization higher than 3000, 4000, or 5000.

[0222] In some embodiments, the nanocellulose material is characterized by having a unimodal degree of polymerization distribution. In other embodiments, the nanocellulose material is characterized by having a bimodal degree of polymerization distribution, such as one peak concentrated in the range of 150-250 and another peak concentrated in the range of 300-700.

[0223] In some embodiments, the nanocellulose material is characterized by particles with an average length-to-width ratio ranging from about 10 to about 1000, such as about 15, 20, 25, 35, 50, 75, 100, 150, 200, 250, 300, 400, or 500. Compared to nanocrystals, nanofibrils are generally associated with a higher aspect ratio. For example, nanocrystals can have a length range of about 100 nm to 500 nm and a diameter of about 4 nm, which translates to an aspect ratio of 25 to 125. Nanofibrils can have a length of about 2000 nm and a diameter range of 5 to 50 nm, which translates to an aspect ratio of 40 to 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.

[0224] In some embodiments, the nanocellulose contains less than 0.05 wt% sulfur, such as about 0.02 wt% sulfur or less, including no detectable sulfur. In some embodiments, the nanocellulose does not contain sulfate half-ester groups attached to the surface of the nanocellulose particles, as these groups can reduce the thermal stability of the nanocellulose.

[0225] Optionally, the nanocellulose itself is functionalized with one or more surface functional groups to produce nanocellulose derivatives. This functionalization can be performed to improve compatibility with the matrix polymer, for example, or to impart special properties to the nanocellulose. Because nanocellulose has a high surface area and a high concentration of surface hydroxyl groups, targeted surface modification can introduce almost any desired level of surface functionality.

[0226] For example, nanocellulose derivatives 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. Different types of nanocellulose functionalization or derivatization can be employed, such as functionalization using polymers, chemical surface modification, functionalization using nanoparticles (i.e., nanoparticles other than nanocellulose), modification using inorganic substances or surfactants, or biochemical modification.

[0227] In some embodiments, nanocellulose is incorporated with a polymer or a combination of polymers to form a molten phase, such as in polymer extrusion, injection molding, compression molding, calendering, etc. For example, nanocellulose can be introduced into the molten phase as part of a nanocellulose dispersion concentrate and / or as part of a nanocellulose dispersion masterbatch.

[0228] One or more additives may be introduced during the method, wherein these additives may 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 fibers, carbon nanotubes, graphene, lignin-derived carbon, or lignin, are used.

[0229] The matrix polymer can be selected broadly, as previously described. The polymer or combination of polymers may include polyesters, polyolefins, polyamides, polystyrene, styrene-based rubbers, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyacrylates, polyhydroxyalkanoates, poly(olefin dicarboxylate), silicones, thermoplastic elastomers, thermoplastic polyurethanes (TPUs), synthetic rubbers, natural rubbers, or combinations or copolymers thereof.

[0230] In some embodiments, the polymer or combination of polymers comprises polylactide. In some embodiments, the polymer or combination of polymers comprises polyhydroxyalkanoates. In some embodiments, the polymer or combination of polymers comprises aliphatic-aromatic copolyesters. In various embodiments, the polymer or combination of polymers comprises polylactide, aliphatic-aromatic copolyesters, poly(butylene adipate-co-terephthalate), poly(butylene adipate), or poly(butylene succinate). In some embodiments, the polymer or combination of polymers comprises polyethylene and / or polypropylene.

[0231] In some embodiments, the polymer or combination of polymers includes polyester, polyolefin, polyamide, polystyrene, styrene-based rubber, natural rubber, synthetic rubber, polyurethane, polyurea, poly(amide-enamine), polyanhydride, polyacrylate, polyhydroxyalkanoate, poly(olefin dicarboxylate), silicone, thermoplastic elastomer, thermoplastic polyurethane (TPU), synthetic rubber, natural rubber, or combinations or copolymers thereof. Some polymer blends include polylactide, polyhydroxyalkanoate, aliphatic-aromatic copolyester, both polylactide and aliphatic-aromatic copolyester, polyethylene and / or polypropylene.

[0232] Polymers that may be included in composite products can be, for example, hydrophobic, partially hydrophobic, or oleophilic. Hydrophilic polymers can be modified to be at least partially hydrophobic by suitable coatings or combinations of components (e.g., interpenetrating networks of polymers).

[0233] In some embodiments, the polymer is selected from polyesters, polyolefins, polyamides, polystyrene, styrene rubbers, polyurethanes, polyureas, poly(amide-enamine), polyanhydrides, polyacrylates, polyhydroxyalkanoates, poly(olefin dicarboxylates), silicones, and combinations or copolymers thereof (e.g., aliphatic-aromatic copolyesters).

[0234] 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 polylactide), poly(glycolic acid) (or polyglycolic acid), 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 glycol carbonate), poly(1,4-butanediol adipate), poly(1,4-butanediol succinate), poly(1,4-butanediol terephthalate), poly(ethylene glycol succinate), poly(vinyl acetate), poly(propylene glycol), poly(tetrahydrofuran), poly(ethyl vinyl ether), polydimethylsiloxane, nylon (aliphatic polyamide), and combinations or copolymers thereof. Carbonaceous polymers can also be incorporated into composite materials. Examples of carbonaceous polymers include polyacenaphthene, graphite, graphene, carbon fiber, and lignin.

[0235] Polymers or copolymers can be produced by polymerizing one or more monomers selected from the group consisting of: acrylics, amides, carbons, carbonates, dienes, esters, ethers, fluorocarbons, imides, olefins, organic acids (e.g., lactic acid, glycolic acid, succinic acid, hydroxypropionic acid, etc.), styrene, siloxanes, vinyl acetals, vinyl chloride and vinylidene chloride, vinyl esters, vinyl ethers, vinyl ketones, vinyl pyridine, vinyl pyrrolidone, and combinations thereof.

[0236] The polymer in a polymer composite material may include thermoplastic polymers, thermosetting polymers, or combinations thereof. Thermosetting polymers include, but are not limited to, polyurethanes, polyesters, polyureas, polyisoprene (including natural or synthetic rubber), phenolic resins, polyepoxides, polyimides, polycyanurates, polyfurans, silicones, and combinations or copolymers thereof.

[0237] In some embodiments, the polymer is specifically an elastomer. Exemplary elastomers include natural rubber (e.g., non-vulcanized natural latex rubber) and synthetic rubber. Natural rubber is primarily polycis-isoprene. Synthetic rubber is made from various petroleum-based monomers. The most common synthetic rubber is styrene-butadiene rubber (SBR), a copolymer derived from styrene and 1,3-butadiene. Other synthetic rubbers are prepared from isoprene (2-methyl-1,3-butadiene, producing polyisoprene), chloroprene (2-chloro-1,3-butadiene), and isobutylene (methpropylene), wherein a small percentage of isoprene is used for crosslinking (to manufacture butyl rubber).

[0238] 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 carrier polymer is or includes biodegradable polymers, such as those described in Vroman and Tighzert, "Biodegradable Polymers." Materials [ Material [2009, 2, 307-344 (which are hereby incorporated herein by reference)] any polymers described therein. In some embodiments of the invention, the nanocellulose-polymer composite product has a renewable carbon content of at least 50%, 60%, 70%, 80%, 90%, 95%, or 100%, such as by means of, for example 13 C analysis is measurable.

[0239] Some methods further involve using well-known polymer processing techniques to form hardened or finished polymer composites from the molten phase. A wide variety of industrial and consumer products can be made from nanocellulose-polymer composite products. These include any known polymer-containing products, as well as newer products such as engineered composites. Many types of products are possible, including films, coatings, packaging, appliances, fibers, fabrics, clothing, durable goods, nonwoven materials, and more.

[0240] The final composite material product may take the form of, for example, granules, extruded parts, injection molded parts, blow molded parts, spun fibers, layered sheets, films, foams, containers, bags, engineered parts, 3D-printed substrates, 3D-printed parts, or combinations thereof.

[0241] Nanocellulose-polymer composite products can be 3D-printed. Three-dimensional (3D) printing, or additive manufacturing, is a process by which an object is created in its three-dimensional form using a specialized printer. With the aid of a 3D modeling program, the printer receives instructions from a design file created in a computer. The file or blueprint of the object to be printed is then segmented into a two-dimensional (2D) representation that is sent to the printer. Multiple layers of material are built based on the information contained in the file; these layers continue to be added until the complete object is printed. Compared to 2D printing, 3D printing processes require a longer time and involve a significant capital investment, but offer a wide range of advantages—such as the ability to print virtually any geometry. In some embodiments of 3D printing, a masterbatch and a 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 manufactured and then introduced into a 3D printer for manufacturing a selected geometry. Note that 3D printing can also be used to create unique masterbatch granule geometries by feeding a carrier polymer and a nanocellulose-dispersion concentrate into the 3D printer. This may be desirable for sales purposes.

[0242] Among the composite products presented in this article, those with dispersed nanocellulose exhibit a higher tensile modulus compared to polymers alone, or to composites that are otherwise identical without dispersants / drying agents.

[0243] Among the composite products presented in this article, those with dispersed nanocellulose exhibit a higher tensile modulus compared to polymers alone, or to composites that are otherwise identical without dispersants / drying agents.

[0244] Among the composite products presented in this article, those with dispersed nanocellulose exhibit a higher compressive modulus compared to polymers alone, or to composites that are otherwise identical without dispersants / drying agents.

[0245] Among the composite products presented in this article, those with dispersed nanocellulose exhibit higher toughness compared to polymers alone, or to composites that are otherwise identical without dispersants / drying agents.

[0246] Among the composite products presented in this article, those with dispersed nanocellulose exhibit better moisture barrier and / or oxygen barrier properties compared to polymers alone, or to composites that are otherwise identical without dispersants / drying agents.

[0247] Due to the inherent properties of nanocellulose particles and because those nanocellulose particles are well dispersed in the composite material by dispersants / drying agents, the tensile modulus, compressive modulus, toughness, and other properties of the composite product are improved.

[0248] The dispersion of nanocellulose in the final composite material, or in nanocellulose dispersion concentrates or masterbatches, can be measured or qualitatively evaluated. Dispersion is the inverse of aggregation. If a perfect, uniform dispersion exists, there is no particle aggregation. This invention does not require perfect dispersion such that each individual nanoparticle is separated from every other nanoparticle.

[0249] Nanocellulose dispersion can be measured or qualitatively evaluated using techniques such as 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 to 8 (See Examples 1 through 8 respectively) are optical micrographs showing good dispersion (no aggregation), and Figure 11 To form a control, Figure 11 These are optical micrographs showing differential dispersion (significant particle aggregation).

[0250] Calibration techniques can also be used to measure or qualitatively evaluate the dispersion of nanocellulose, in which relevant properties of empirically proven polymers with known nanocellulose dispersions are tested. The same properties of the test sample related to the dispersion of nanocellulose are then measured using predetermined graphs, equations, or lookup tables.

[0251] In the final composite product, the dispersant / drying agent may be in the same phase as the nanocellulose, in the same phase as the matrix material, and / or in a different phase (or no longer present, as explained above). The dispersant / drying agent may be disposed between the nanocellulose particles and the matrix material. In some embodiments, the dispersant / drying agent surrounds the nanocellulose particles. The carrier material may be in the same phase as the nanocellulose, in the same phase as the matrix material, and / or in a different phase (or absent).

[0252] In some embodiments, the method includes forming a structural object comprising a composite material product containing nanocellulose, or a derivative thereof.

[0253] In some embodiments, the method includes forming a foam or aerogel comprising a composite material product containing nanocellulose, or a derivative thereof.

[0254] In some embodiments, the method includes combining a composite product containing nanocellulose, or a derivative thereof, with one or more other carbon materials to form a composite material containing nanocellulose, carbon, and a matrix material.

[0255] In some embodiments, the method includes forming a membrane comprising a composite material product containing nanocellulose, or a derivative thereof. In some embodiments, the membrane is optically transparent and flexible.

[0256] In some embodiments, the method includes forming a coating or coating precursor comprising a composite product containing nanocellulose, or a derivative thereof.

[0257] In some embodiments, the composite product containing nanocellulose is configured as a catalyst, catalyst substrate, or co-catalyst. In some embodiments, the composite product containing nanocellulose is electrochemically configured to carry or store current or voltage.

[0258] In some embodiments, the composite product containing nanocellulose is incorporated into a filter, membrane, or other separation device.

[0259] In some embodiments, the nanocellulose-containing composite product is incorporated as an additive into coatings, paints, or adhesives. In some embodiments, the nanocellulose-containing composite product is a cement additive.

[0260] Composite products containing nanocellulose can include any of the disclosed compositions. Many composite products are possible. For example, composite products can be selected from the group consisting of: structural objects, foams, aerogels, carbon composites, membranes, coatings, coating precursors, current or voltage carriers, filters, films, catalysts, catalyst substrates, coatings or coating additives, paints or paint additives, adhesives or adhesive additives, inks or ink additives, cement additives, paper coatings or paper additives, thickeners, rheology modifiers, additives for drilling fluids, and combinations or derivatives thereof.

[0261] The nanocellulose-containing composite products presented herein are suitable as coating materials because they are expected to have high oxygen barrier properties and affinity for wood fibers for use in food packaging and printing paper. Alternatively, or additionally, for example, the nanocellulose-containing composite products can be incorporated into products to improve barrier properties or improve nucleation.

[0262] The nanocellulose-containing composite products presented in this article are suitable as additives to improve the durability of paints, thereby protecting paints and varnishes from wear caused by UV radiation.

[0263] The nanocellulose-containing composite products presented herein are suitable as thickeners in food and cosmetic products. Nanocellulose can be used as a thixotropic, biodegradable, and dimensionally stable thickener (stable against temperature and salt addition). The nanocellulose-polymer composite products presented herein are suitable as Pickering stabilizers for emulsions and particulate-stabilized foams. The large surface area of ​​nanocellulose combined with its biodegradability makes it an attractive material for highly porous, mechanically stabilized aerogels.

[0264] In other embodiments, the nanocellulose-dispersion masterbatch is used as, or incorporated into, the following: structural objects, foams, aerogels, carbon composites, membranes, coatings, coating precursors, current or voltage carriers, filters, films, 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.

[0265] In other embodiments, the nanocellulose-dispersion concentrate is incorporated into the following: structural objects, foams, aerogels, carbon composites, membranes, coatings, coating precursors, current or voltage carriers, filters, films, 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 applications suitable for this invention include high-strength spun fibers and textiles, advanced composite materials, barrier membranes, paints, varnishes, adhesives, switchable optics, pharmaceuticals, drug delivery systems, bone replacement, dental restorations, paper, packaging, building products, additives for food and cosmetics, and hydrogels.

[0266] Aerospace and transportation composites can benefit from the disclosed nanocellulose-dispersion concentrates or masterbatches. Automotive applications include nanocellulose composites with polypropylene, polyamide (e.g., nylon), or polyester (e.g., PBT).

[0267] The nanocellulose-dispersion concentrates or masterbatches presented herein are suitable as strength-enhancing additives for renewable and biodegradable composite materials. Dispersants / drying agents can act as binders between two organic phases to improve fracture toughness and prevent crack formation for applications in packaging, building materials, home appliances, and renewable fibers.

[0268] The nanocellulose-dispersion concentrate or masterbatch provided in this article is suitable as a transparent and dimensionally stable strength-enhancing additive for use in flexible displays, flexible circuits, printable electronics, and flexible solar panels.

[0269] The nanocellulose-dispersion concentrates or masterbatches presented in this article are suitable for composite materials and cement additives, thereby allowing for crack reduction and increased toughness and strength. Foamed, porous nanocellulose-concrete hybrids allow for lightweight structures with increased crack reduction and strength.

[0270] The strength enhancement achieved through the use of nanocellulose increases both the bonding area and bonding strength, enabling its application in high-strength, high-bulk, high-filler-content paper and paperboard with enhanced moisture and oxygen barrier properties. The pulp and paper industry can particularly benefit from the nanocellulose dispersion concentrates or masterbatches presented herein.

[0271] In some embodiments, nanocellulose-dispersion concentrate is incorporated as a thickener or rheology modifier. For example, nanocellulose-dispersion concentrate may be an additive in drilling fluids or fracturing fluids such as (but not limited to) oil recovery fluids and / or natural gas recovery fluids.

[0272] Nanocellulose-dispersion concentrates can generally be used in any system that can benefit from their incorporation. As discussed in this specification, systems include, but are not limited to, polymers, oligomers, paper, paperboard, fiber and wood composites, emulsions, hydrogels, carbon, organic solids, inorganic solids, oils, organic liquids, inorganic liquids, cementing materials (e.g., concrete or cement), minerals, ceramics, metals, metal alloys, glass, or combinations thereof. For example, non-polymer matrix materials can be adhesive matrices, battery electrode matrices, bio-ink matrices, or electronic ink matrices.

[0273] Example Example 1: Preparation of nanocellulose-dispersion concentrate and nanocellulose-polypropylene composite material.

[0274] Lignin-coated nanofibers are obtained by fractionating lignocellulose biomass (cork fragments) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce cellulose-rich solids, which are then mechanically processed to produce lignin-coated nanofibers. The lignin-coated nanofibers are present in an aqueous suspension containing approximately 3 wt% solids. This aqueous suspension may be referred to as a nanocellulose gel.

[0275] Based on lignin-coated nanofibers and a selected matrix polymer (polypropylene), the dispersant / drying agent was chosen as a copolymer of ethylene and maleic anhydride. The specific dispersant / drying agent is Honeywell AC® 573A wax (Honeywell Performance Materials and Technologies, Morris Plains, New Jersey, USA), which is an ethylene-maleic anhydride copolymer in powder form. Honeywell AC® 573A wax is a low molecular weight copolymer of maleic anhydride with propylene or ethylene. Functionalizing nonpolar propylene or ethylene with maleic anhydride provides a copolymer with both nonpolar and polar characteristics. According to Honeywell, maleic anhydride provides polarity without polymer degradation.

[0276] A starting nanocellulose-dispersion concentrate was produced by combining 2,917 g of an aqueous suspension of lignin-coated nanofibrils with 88 g of the dispersant / drying agent described above to produce a starting slurry under mechanical stirring. The starting nanocellulose-dispersion slurry initially contained approximately 3 wt% nanocellulose (lignin-coated nanofibrils) and approximately 94 wt% water. The starting slurry was mixed using a Brabender PL200 Plasti-Corder torque rheometer with a Haake Rheomix 3000 mixer at a mixing blade speed of 100 rpm and a temperature of 120°C, and dried using a semi-batch method under heating and shearing. As the volume in the mixer bowl decreased with the evaporation of water, the slurry was continuously added to the rheometer. This process continued until all the slurry had been fed and until all the water had evaporated from the material, lasting approximately 90 minutes, at which point the dried concentrate was removed from the mixer. For example, by pre-concentrating the slurry via centrifugation, processing time during drying and the amount of water that needs to be removed can be significantly reduced. During mixing under heating, water is allowed to evaporate from the nanocellulose gel. When water is removed under shear mixing, the nanocellulose is prevented from agglomerating and binding itself, and the wax phase acts as a spacer between the nanocellulose particles.

[0277] Once virtually all the water has been removed from the initial nanocellulose-dispersion slurry, the result is a nanocellulose-dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanofibers) and approximately 50 wt% dispersant / drying agent. While removal of all water is preferred, it is possible that some residual moisture may remain in the nanocellulose-dispersion concentrate. It will also be understood that other nanocellulose concentrations may be used for the nanocellulose-dispersion concentrate.

[0278] The obtained nanocellulose-dispersion concentrate was then ground into powder using a Bel-Art micromill. The resulting powder was then dispersed in polypropylene as follows: Four parts by weight of the nanocellulose-dispersion concentrate (meaning two parts nanocellulose and two parts dispersant / drying agent) and 96 parts by weight of the polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) were combined and mixed in a Brabender torque rheometer. The rheometer was run at 40 RPM and 150°C for 11 minutes. The resulting nanocellulose-polymer composite material is shown in... Figure 1 The optical micrograph (100× magnification) shows 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0279] Example 2: Preparation of nanocellulose-dispersion concentrate and nanocellulose-polypropylene composite material.

[0280] The lignin-coated nanofibers are obtained by fractionating lignocellulosic biomass (cork fragments) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce cellulose-rich solids, which are then mechanically processed to produce lignin-coated nanofibers. The lignin-coated nanofibers are present in an aqueous suspension (gel) containing approximately 3 wt% solids.

[0281] Based on the lignin-coated nanofibers and the selected matrix polymer (polypropylene), the dispersant / drying agent was chosen as a copolymer of ethylene and acrylic acid. Specifically, the dispersant / drying agent was Honeywell AClyn® 295A wax (Honeywell Performance Materials and Technologies, Morris Plains, NJ, USA), a zinc ionomer of the ethylene-acrylic acid copolymer in powder form, 98% neutralized with zinc (corrosion protection).

[0282] A starting nanocellulose-dispersion slurry was prepared by combining 2,917 g of an aqueous suspension of lignin-coated nanofibers with 88 g of the dispersant / drying agent described above under mechanical stirring. The starting nanocellulose-dispersion slurry initially contained approximately 3 wt% nanocellulose (lignin-coated nanofibers) and approximately 94 wt% water. The starting slurry was mixed using a Brabender PL200 Plasti-Corder torque rheometer with a Haake Rheomix 3000 mixer at a mixing blade speed of 100 rpm and a temperature of 120°C, and dried using a semi-batch method under heating and shearing. As the volume in the mixer bowl decreased with the evaporation of water, the slurry was continuously added to the rheometer. This process continued until all the slurry had been fed and until all the water had evaporated from the material, lasting approximately 90 minutes, at which point the dried concentrate was removed from the mixer. For example, by pre-concentrating the slurry via centrifugation, processing time during drying and the amount of water that needs to be removed can be significantly reduced. During mixing under heating, water is allowed to evaporate from the nanocellulose gel. When water is removed under shear mixing, the nanocellulose is prevented from agglomerating and binding itself, and the wax phase acts as a spacer between the nanocellulose particles.

[0283] Once virtually all the water has been removed from the initial nanocellulose-dispersion slurry, the result is a nanocellulose-dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanofibers) and approximately 50 wt% dispersant / drying agent. While removal of all water is preferred, it is possible that some residual moisture may remain in the nanocellulose-dispersion concentrate. It will also be understood that other nanocellulose concentrations may be used for the nanocellulose-dispersion concentrate.

[0284] The obtained nanocellulose-dispersion concentrate was then ground into powder using a Bel-Art micromill. The resulting powder was then dispersed in polypropylene as follows: Four parts by weight of the nanocellulose-dispersion concentrate and 96 parts by weight of the polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) were combined and mixed in a Brabender torque rheometer. The rheometer was run at 40 RPM and 150°C for 11 minutes. The resulting nanocellulose-polymer composite material is shown in... Figure 2 The optical micrograph (100× magnification) shows 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0285] Example 3: Preparation of nanocellulose-dispersion concentrate and nanocellulose-polypropylene composite material.

[0286] The lignin-coated nanofibers are obtained by fractionating lignocellulosic biomass (cork fragments) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce cellulose-rich solids, which are then mechanically processed to produce lignin-coated nanofibers. The lignin-coated nanofibers are present in an aqueous suspension (gel) containing approximately 3 wt% solids.

[0287] Based on the lignin-coated nanofibers and the selected matrix polymer (polypropylene), the dispersant / drying agent was chosen as a copolymer of ethylene and acrylic acid. Specifically, the dispersant / drying agent was Honeywell AClyn® 201A wax (Honeywell Performance Materials and Technologies, Morris Plains, NJ, USA), a calcium ionomer of the ethylene-acrylic acid copolymer in powder form, 47% of which was neutralized with calcium.

[0288] A starting nanocellulose-dispersion slurry was prepared by combining 2,917 g of an aqueous suspension of lignin-coated nanofibers with 88 g of the dispersant / drying agent described above under mechanical stirring. The starting nanocellulose-dispersion slurry initially contained approximately 3 wt% nanocellulose (lignin-coated nanofibers) and approximately 94 wt% water. The starting slurry was mixed using a Brabender PL200 Plasti-Corder torque rheometer with a Haake Rheomix 3000 mixer at a mixing blade speed of 100 rpm and a temperature of 120°C, and dried using a semi-batch method under heating and shearing. As the volume in the mixer bowl decreased with the evaporation of water, the slurry was continuously added to the rheometer. This process continued until all the slurry had been fed and until all the water had evaporated from the material, lasting approximately 90 minutes, at which point the dried concentrate was removed from the mixer. For example, by pre-concentrating the slurry via centrifugation, processing time during drying and the amount of water that needs to be removed can be significantly reduced. During mixing under heating, water is allowed to evaporate from the nanocellulose gel. When water is removed under shear mixing, the nanocellulose is prevented from agglomerating and binding itself, and the wax phase acts as a spacer between the nanocellulose particles.

[0289] Once substantially all the water has been removed from the initial nanocellulose dispersion concentrate, the result is a nanocellulose dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanofibers) and approximately 50 wt% dispersant / drying agent. While removal of all water is preferred, it is possible that some residual moisture may remain in the nanocellulose dispersion concentrate. It will also be understood that other nanocellulose concentrations may be used for the nanocellulose dispersion concentrate.

[0290] The obtained nanocellulose-dispersion concentrate was then ground into powder using a Bel-Art micromill. The resulting powder was then dispersed in polypropylene as follows: Four parts by weight of the nanocellulose-dispersion concentrate and 96 parts by weight of the polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) were combined and mixed in a Brabender torque rheometer. The rheometer was run at 40 RPM and 150°C for 11 minutes. The resulting nanocellulose-polymer composite material is shown in... Figure 3 The optical micrograph (100× magnification) shows 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0291] Example 4: Preparation of nanocellulose-dispersion concentrate and nanocellulose-polypropylene composite material.

[0292] The lignin-coated nanofibers are obtained by fractionating lignocellulosic biomass (cork fragments) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce cellulose-rich solids, which are then mechanically processed to produce lignin-coated nanofibers. The lignin-coated nanofibers are present in an aqueous suspension (gel) containing approximately 3 wt% solids.

[0293] Based on the lignin-coated nanofibers and the selected matrix polymer (polypropylene), the dispersant / drying agent was chosen as a copolymer of ethylene and acrylic acid. Specifically, the dispersant / drying agent is Honeywell AC® 540A wax (Honeywell Performance Materials and Technologies, Morris Plains, NJ, USA), which is an ethylene-acrylic acid copolymer in powder form. Honeywell AC® 540A wax contains 5 wt% acrylic acid.

[0294] A starting nanocellulose-dispersion slurry was prepared by combining 2,917 g of an aqueous suspension of lignin-coated nanofibers with 88 g of the dispersant / drying agent described above under mechanical stirring. The starting nanocellulose-dispersion slurry initially contained approximately 3 wt% nanocellulose (lignin-coated nanofibers) and approximately 94 wt% water. The starting slurry was mixed using a Brabender PL200 Plasti-Corder torque rheometer with a Haake Rheomix 3000 mixer at a mixing blade speed of 100 rpm and a temperature of 120°C, and dried using a semi-batch method under heating and shearing. As the volume in the mixer bowl decreased with the evaporation of water, the slurry was continuously added to the rheometer. This process continued until all the slurry had been fed and until all the water had evaporated from the material, lasting approximately 90 minutes, at which point the dried concentrate was removed from the mixer. For example, by pre-concentrating the slurry via centrifugation, processing time during drying and the amount of water that needs to be removed can be significantly reduced. During mixing under heating, water is allowed to evaporate from the nanocellulose gel. When water is removed under shear mixing, the nanocellulose is prevented from agglomerating and binding itself, and the wax phase acts as a spacer between the nanocellulose particles.

[0295] Once substantially all the water has been removed from the initial nanocellulose dispersion concentrate, the result is a nanocellulose dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanofibers) and approximately 50 wt% dispersant / drying agent. While removal of all water is preferred, it is possible that some residual moisture may remain in the nanocellulose dispersion concentrate. It will also be understood that other nanocellulose concentrations may be used for the nanocellulose dispersion concentrate.

[0296] The obtained nanocellulose-dispersion concentrate was then ground into powder using a Bel-Art micromill. The resulting powder was then dispersed in polypropylene as follows: Four parts by weight of the nanocellulose-dispersion concentrate and 96 parts by weight of the polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) were combined and mixed in a Brabender torque rheometer. The rheometer was run at 40 RPM and 150°C for 11 minutes. The resulting nanocellulose-polymer composite material is shown in... Figure 4 The optical micrograph (100× magnification) shows 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0297] Example 5: Preparation of nanocellulose-dispersion concentrate and nanocellulose-polypropylene composite material.

[0298] The lignin-coated nanofibers are obtained by fractionating lignocellulosic biomass (cork fragments) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce cellulose-rich solids, which are then mechanically processed to produce lignin-coated nanofibers. The lignin-coated nanofibers are present in an aqueous suspension (gel) containing approximately 3 wt% solids.

[0299] Based on the lignin-coated nanofibers and the selected matrix polymer (polypropylene), the dispersant / drying agent was chosen as a copolymer of ethylene and acrylic acid. Specifically, the dispersant / drying agent is Honeywell AC® 580 wax (Honeywell Performance Materials and Technologies, Morris Plains, NJ, USA), which is an ethylene-acrylic acid copolymer in granular form. Honeywell AC® 580 wax contains 10 wt% acrylic acid and has an acid value of 75.

[0300] A starting nanocellulose-dispersion slurry was prepared by combining 2,917 g of an aqueous suspension of lignin-coated nanofibers with 88 g of the dispersant / drying agent described above under mechanical stirring. The starting nanocellulose-dispersion slurry initially contained approximately 3 wt% nanocellulose (lignin-coated nanofibers) and approximately 94 wt% water. The starting slurry was mixed using a Brabender PL200 Plasti-Corder torque rheometer with a Haake Rheomix 3000 mixer at a mixing blade speed of 100 rpm and a temperature of 120°C, and dried using a semi-batch method under heating and shearing. As the volume in the mixer bowl decreased with the evaporation of water, the slurry was continuously added to the rheometer. This process continued until all the slurry had been fed and until all the water had evaporated from the material, lasting approximately 90 minutes, at which point the dried concentrate was removed from the mixer. For example, by pre-concentrating the slurry via centrifugation, processing time during drying and the amount of water that needs to be removed can be significantly reduced. During mixing under heating, water is allowed to evaporate from the nanocellulose gel. When water is removed under shear mixing, the nanocellulose is prevented from agglomerating and binding itself, and the wax phase acts as a spacer between the nanocellulose particles.

[0301] Once substantially all the water has been removed from the initial nanocellulose dispersion concentrate, the result is a nanocellulose dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanofibers) and approximately 50 wt% dispersant / drying agent. While removal of all water is preferred, it is possible that some residual moisture may remain in the nanocellulose dispersion concentrate. It will also be understood that other nanocellulose concentrations may be used for the nanocellulose dispersion concentrate.

[0302] The obtained nanocellulose-dispersion concentrate was then ground into powder using a Bel-Art micromill. The resulting powder was then dispersed in polypropylene as follows: Four parts by weight of the nanocellulose-dispersion concentrate and 96 parts by weight of the polypropylene random copolymer (ExxonMobil, Houston, Texas, USA) were combined and mixed in a Brabender torque rheometer. The rheometer was run at 40 RPM and 150°C for 11 minutes. The resulting nanocellulose-polymer composite material is shown in... Figure 5 The optical micrograph (100× magnification) shows 2 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in polypropylene.

[0303] Example 6: Preparation of nanocellulose-dispersion concentrate and nanocellulose-polylactide composite material.

[0304] The lignin-coated nanocrystals were 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 cellulose-rich solids, which were then mechanically processed to produce lignin-coated nanocrystals. The lignin-coated nanocrystals were present in an aqueous suspension (gel) containing approximately 6 wt% solids.

[0305] Based on the lignin-coated nanocrystals and the selected matrix polymer (polylactide), the dispersant / drying agent was chosen as a copolymer of ethylene and acrylic acid. Specifically, the dispersant / drying agent is Honeywell AC® 540A wax (Honeywell Performance Materials and Technologies, Morris Plains, NJ, USA), which is an ethylene-acrylic acid copolymer in powder form. Honeywell AC® 540A wax contains 5 wt% acrylic acid.

[0306] A starting nanocellulose-dispersion slurry was produced by combining 1,458 g of an aqueous suspension of lignin-coated nanocrystals with 88 g of the dispersant / drying agent described above under mechanical stirring. The starting nanocellulose-dispersion slurry initially contained approximately 6 wt% nanocellulose (lignin-coated nanocrystals) and approximately 89 wt% water. The starting slurry was mixed using a Brabender PL200 Plasti-Corder torque rheometer with a Haake Rheomix 3000 mixer at a mixing blade speed of 100 rpm and a temperature of 120°C, and dried using a semi-batch method under heating and shearing. As the volume in the mixer bowl decreased with the evaporation of water, the slurry was continuously added to the rheometer. This process continued until all the slurry had been fed and until all the water had evaporated from the material, lasting approximately 90 minutes, at which point the dried concentrate was removed from the mixer. For example, by pre-concentrating the slurry via centrifugation, the processing time and the amount of water that needs to be removed during drying can be significantly reduced. During mixing under heating, water is allowed to evaporate from the nanocellulose gel. When water is removed under shear mixing, the nanocellulose is prevented from agglomerating and binding itself, and the wax phase acts as a spacer between the nanocellulose particles.

[0307] Once substantially all the water has been removed from the initial nanocellulose dispersion concentrate, the result is a nanocellulose dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanocrystals) and approximately 50 wt% dispersant / drying agent. While removal of all water is preferred, it is possible that some residual moisture may remain in the nanocellulose dispersion concentrate. It will also be understood that other nanocellulose concentrations may be used for the nanocellulose dispersion concentrate.

[0308] The obtained nanocellulose-dispersion concentrate was then ground into powder using a Bel-Art micromill. The resulting powder was then dispersed in polylactide as follows: One part by weight of the nanocellulose-dispersion concentrate and 99 parts by weight of polylactide (INGEO® PLA 4043D, NatureWorks LLC, Minnetonka, Minnesota, USA) were combined and mixed in a Brabender torque rheometer. The rheometer was run at 40 RPM and 140°C for 11 minutes. The resulting nanocellulose-polymer composite material is shown in... Figure 6 The optical micrograph (100× magnification) shows 0.5 wt% nanocellulose (lignin-coated nanocrystals) uniformly dispersed in polylactide.

[0309] Example 7: Preparation of nanocellulose-dispersion concentrate and nanocellulose-polylactide composite material.

[0310] The lignin-coated nanocrystals were 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 cellulose-rich solids, which were then mechanically processed to produce lignin-coated nanocrystals. The lignin-coated nanocrystals were present in an aqueous suspension (gel) containing approximately 6 wt% solids.

[0311] Based on the lignin-coated nanofibers and the selected matrix polymer (polylactide), the dispersant / drying agent was chosen as a copolymer of ethylene and acrylic acid. Specifically, the dispersant / drying agent was Honeywell AC® 580 wax (Honeywell Performance Materials and Technologies, Morris Plains, NJ, USA), which is an ethylene-acrylic acid copolymer in granular form. Honeywell AC® 580 wax contains 10 wt% acrylic acid and has an acid value of 75.

[0312] A starting nanocellulose-dispersion slurry was produced by combining 1,458 g of an aqueous suspension of lignin-coated nanocrystals with 88 g of the dispersant / drying agent described above under mechanical stirring. The starting nanocellulose-dispersion slurry initially contained approximately 6 wt% nanocellulose (lignin-coated nanocrystals) and approximately 89 wt% water. The starting slurry was mixed using a Brabender PL200 Plasti-Corder torque rheometer with a Haake Rheomix 3000 mixer at a mixing blade speed of 100 rpm and a temperature of 120°C, and dried using a semi-batch method under heating and shearing. As the volume in the mixer bowl decreased with the evaporation of water, the slurry was continuously added to the rheometer. This process continued until all the slurry had been fed and until all the water had evaporated from the material, lasting approximately 90 minutes, at which point the dried concentrate was removed from the mixer. For example, by pre-concentrating the slurry via centrifugation, the processing time and the amount of water that needs to be removed during drying can be significantly reduced. During mixing under heating, water is allowed to evaporate from the nanocellulose gel. When water is removed under shear mixing, the nanocellulose is prevented from agglomerating and binding itself, and the wax phase acts as a spacer between the nanocellulose particles.

[0313] Once substantially all the water has been removed from the initial nanocellulose dispersion concentrate, the result is a nanocellulose dispersion concentrate containing approximately 50 wt% nanocellulose (lignin-coated nanocrystals) and approximately 50 wt% dispersant / drying agent. While removal of all water is preferred, it is possible that some residual moisture may remain in the nanocellulose dispersion concentrate. It will also be understood that other nanocellulose concentrations may be used for the nanocellulose dispersion concentrate.

[0314] The obtained nanocellulose-dispersion concentrate was then ground into powder using a Bel-Art micromill. The resulting powder was then dispersed in polylactide as follows: One part by weight of the nanocellulose-dispersion concentrate and 99 parts by weight of polylactide (INGEO® PLA 4043D, NatureWorks LLC, Minnetonka, Minnesota, USA) were combined and mixed in a Brabender torque rheometer. The rheometer was run at 40 RPM and 140°C for 11 minutes. The resulting nanocellulose-polymer composite material is shown in... Figure 7 The optical micrograph (100× magnification) shows 0.5 wt% nanocellulose (lignin-coated nanocrystals) uniformly dispersed in polylactide.

[0315] Example 8: Preparation of nanocellulose-dispersion concentrates for non-aqueous chemical systems.

[0316] The lignin-coated cellulose nanofibers were obtained by fractionating lignocellulose biomass (cork fragments) in the presence of an acid catalyst (sulfur dioxide), a solvent for lignin (ethanol), and water to produce cellulose-rich solids, which were then mechanically processed to produce lignin-coated nanocrystals. The lignin-coated nanocrystals were present in an aqueous suspension (gel) containing approximately 3 wt% solids.

[0317] The dispersant / drying agent was selected as stearic acid ammonium emulsion and an ammonium salt of stearic acid. Stearic acid is an 18-carbon chain with C64 atoms. 17 H 35 The chemical formula of the fatty acid CO2H is selected for its bifunctional properties, having a polar head group that can react with the hydroxyl groups of nanocellulose and lignin, and a nonpolar chain that imparts solubility in organic solvents.

[0318] A starting nanocellulose-dispersion slurry was prepared by mixing 3889 g of an aqueous suspension of lignin-coated nanofibrils with 58 g of an aqueous emulsion of ammonium stearate dispersant / drying agent. The starting nanocellulose-dispersion slurry initially contained approximately 3 wt% nanocellulose (lignin-coated nanofibrils) and approximately 96 wt% water. The slurry was mixed for 90 minutes at a mixing blade speed of 100 rpm and a temperature of 120°C using a Brabender PL200 Plasti-Corder torque rheometer equipped with a Haake Rheomix 3000 mixer. The slurry was then dried using a semi-batch method under heating and shearing. As the volume in the mixer bowl decreased with water evaporation, the slurry was continuously added to the rheometer. This process continued until all the slurry had been fed and until all the moisture had evaporated from the material, lasting approximately 90 minutes, at which point the dried concentrate was removed from the mixer. For example, by pre-concentrating the slurry via centrifugation, processing time during drying and the amount of water that needs to be removed can be significantly reduced. During mixing under heating, water is allowed to evaporate from the nanocellulose gel. When water is removed under shear mixing, the nanocellulose is prevented from agglomerating and binding itself, and stearic acid (or stearate) acts as a spacer between the nanocellulose particles.

[0319] Once substantially all the water has been removed from the initial nanocellulose dispersion concentrate, the result is a nanocellulose dispersion concentrate containing approximately 67 wt% nanocellulose (lignin-coated nanofibers) and approximately 33 wt% dispersant / drying agent. While removal of all water is preferred, it is possible that some residual moisture may remain in the nanocellulose dispersion concentrate. It will also be understood that other nanocellulose concentrations may be used for the nanocellulose dispersion concentrate.

[0320] The obtained nanocellulose-dispersion concentrate was then milled and dispersed in diisononyl phthalate (DINP) (a common plasticizer) using a hammer mill, as follows. Approximately 2 parts by weight of the nanocellulose-dispersion concentrate and 98 parts by weight of DINP were combined in a vortex mixer under ambient conditions for 4 minutes. The resulting stable, thixotropic non-aqueous nanocellulose dispersion is shown in... Figure 8 The optical micrograph (400× magnification) shows ~1.3 wt% nanocellulose (lignin-coated nanofibers) uniformly dispersed in DINP.

[0321] In this detailed description, reference has been made to various embodiments of the invention and non-limiting examples of how the invention can be understood and practiced. Other embodiments may be used without departing from the spirit and scope of the invention, provided that all the features and advantages listed herein are provided. The invention combines conventional experimentation with optimizations of the methods and systems described herein. Such modifications and variations are considered to be within the scope of the invention as defined by the claims.

[0322] All publications, patents and patent applications cited in this specification are incorporated herein by reference in their entirety as if each publication, patent or patent application had been expressly and separately set forth herein.

[0323] When the methods and steps described above indicate that certain events occur in a certain order, those skilled in the art will recognize that the order of certain steps can be modified, and such modifications are variations of the invention. Furthermore, where possible, some of these steps can be performed simultaneously in parallel processes, or sequentially.

[0324] Therefore, to some extent, there are multiple variations of the invention that are within the spirit of this disclosure or equivalent to the invention known in the appended claims, and it is intended that this patent also cover those variations. The invention should be limited only to the claims.

Claims

1. A nanocellulose dispersion concentrate, comprising: (a) Nanocellulose ranging from about 10 wt% to about 70 wt%; and (b) From about 5 wt% to about 50 wt% of a selected dispersant / drying agent compatible with the nanocellulose, The dispersant / drying agent mentioned above is selected from the group consisting of: waxes, polyolefins, olefin-maleic anhydride copolymers, olefin-acrylic acid copolymers, polyols, fatty acids, fatty alcohols, polyol-glycerol esters, polydimethylsiloxane, polydimethylsiloxane-alkyl esters, polyacrylamide, starch, cellulose derivatives, microparticles, and combinations thereof or reaction products. The weight ratio of the nanocellulose to the dispersant / drying agent is selected from greater than 0.5 to about 2. Furthermore, the nanocellulose-dispersion concentrate is in solid or liquid form.

2. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The nanocellulose-dispersion concentrate is essentially composed of the nanocellulose and the dispersant / drying agent.

3. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The nanocellulose includes cellulose nanocrystals, cellulose nanofibrils, microfibrillated cellulose, or combinations thereof.

4. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The nanocellulose includes lignin-containing nanocellulose.

5. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The nanocellulose includes lignin-coated nanocellulose.

6. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The dispersant / drying agent is a functionalized polyolefin wax that is compatible with the nanocellulose.

7. The nanocellulose-dispersion concentrate as described in claim 6, wherein, The functionalized polyolefin wax is a functionalized polyethylene wax, a functionalized polypropylene wax, a functionalized polybutene wax, or a combination thereof.

8. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The dispersant / drying agent is a low molecular weight oligomer or polymer of ethylene or functionalized ethylene, having a number-average degree of polymerization from 2 to 1000.

9. The nanocellulose-dispersion concentrate as described in claim 8, wherein, The number-average degree of polymerization ranges from 5 to 500.

10. The nanocellulose-dispersion concentrate according to claim 1, wherein, The dispersant / drying agent is a copolymer of (a) one or more C2-C4 olefins and (b) maleic anhydride.

11. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The dispersant / drying agent is (a) a copolymer of one or more C2-C4 olefins and (b) acrylic acid.

12. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The dispersant / drying agent comprises a polyol selected from the following: ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerol, butylene glycol, polybutylene glycol, or combinations thereof, wherein the polyol is optionally esterified with fatty acids.

13. The nanocellulose-dispersion concentrate according to claim 1, wherein, The dispersant / drying agent includes alkyl ester polydimethylsiloxane emulsion.

14. The nanocellulose-dispersion concentrate according to claim 1, wherein, The dispersant / drying agent includes cationic starch, amphoteric starch, thermoplastic starch, or a combination thereof.

15. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The dispersant / drying agent comprises particles selected from the group consisting of: clay, nanoclay, talc, wollastonite, calcium carbonate, silica, mica, kaolin, nickel, glass fiber, bentonite, biotite, illite, kaolin, vermiculite, zeolite, carbon fiber, carbon nanotubes, graphene, or combinations thereof.

16. The nanocellulose-dispersion concentrate as described in claim 15, wherein, The particles have surface charges.

17. The nanocellulose-dispersion concentrate according to claim 1, wherein, The dispersant / drying agent includes at least one fatty acid and at least one particulate.

18. The nanocellulose-dispersion concentrate as described in claim 1, wherein, The nanocellulose-dispersion concentrate further comprises a liquid solvent.

19. The nanocellulose-dispersion concentrate as described in claim 18, wherein, The liquid solvent is selected from the group consisting of: water, C1-C8 alcohols, C2-C8 polyols, and combinations thereof.

20. The nanocellulose-dispersion concentrate according to claim 1, wherein, The nanocellulose-dispersion concentrate further comprises one or more elastomers from about 0.1 wt% to about 50 wt%.

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