The present invention provides, among other things, methods including the steps of providing a cellulosic biomass, associating the cellulosic biomass with an organic liquid to form a mixture, treating the mixture to reduce the moisture content of the mixture to 30% or below (if necessary), and processing the mixture to produce cellulose nanofibrils in a slurry. In some embodiments, provided methods allow for the production of high solids content slurries containing 4% or more cellulosic nanofibrils.

A method for catalytic oxidation of cellulose using a heterocyclic nitroxyl radical as catalyst, main oxidant acting as oxygen source, and an activator of the heterocyclic nitroxyl radical, comprisesa preliminary activation step of the heterocyclic nitroxyl radical with hypochlorite to activated catalyst, and after the preliminary activation step, a cellulose oxidation step using the activated catalyst and hypochlorite as the main oxidant to oxidize cellulose. In the cellulose oxidation step, fibrous starting material is subjected to the oxidation to oxidize the cellulose, whereafter the oxidized fibrous raw material is disintegrated to nanofibrillar cellulose (NFC).

A super strong and tough densified wood structure is formed by subjecting a cellulose-based natural wood material to a chemical treatment that partially removes lignin therefrom. The treated wood retains lumina of the natural wood, with cellulose nanofibers of cell walls being aligned. The treated wood is then pressed in a direction crossing the direction in which the lumina extend, such that the lumina collapse and any residual fluid within the wood is removed. As a result, the cell walls become entangled and hydrogen bonds are formed between adjacent cellulose nanofibers, thereby improving the strength and toughness of the wood among other mechanical properties. By further modifying, manipulating, or machining the densified wood, it can be adapted to various applications.

Bleached polycrylic acid crosslinked cellulose fibers with reduced furfural content are disclosed. The reduced furfural content is accompanied by a strong reduction of malodor associated with crosslinked fibers. Methods of furfural reduction include treatment with hydrogen peroxide in the absence of alkaline or other bleaching agents subsequent to curing polyacrylic acid crosslinked cellulose fibers. Some embodiments of treated polycrylic acid crosslinked cellulose fibers have a furfural content lower than 1.3 ppm. In some embodiments, the reduction of furfural content of the treated crosslinked fibers compared to untreated crosslinked fibers is at least 55%. in some embodiments, furfural content decreases with aging of the treated crosslinked fibers.

The present invention provides a process for preparing a cellulose solution. NMMO with a relatively low concentration and non-activated pulp are continuously mixed online, the mixed premix is dewatered in evaporation dewatering equipment until an NMMO concentration suitable for swelling is achieved, then, sufficient swelling is carried out under this condition, and the uniformly-mixed and sufficiently swelled pre-swelling solution is subjected to depressurized evaporation dewatering and dissolving by thin-film-evaporation equipment thereby obtaining a high-concentration, uniformly-dissolved and excellently-uniformity cellulose solution. The present invention further provides continuous preparation equipment for the process for preparing a cellulose solution. According to the present invention, the conflict between uniform mixing and sufficient swelling during the preparation of a high-concentration cellulose solution is solved, and problems in storage and transportation safety caused by using high concentration NMMO in the conventional technologies are prevented.

The present invention relates to an improved process for producing chemical cellulose pulp wherein biopolymers are added immediately before, during or after a bleaching step, depending on pulp characteristics and on process conditions used. The biopolymers according to the present invention are starches chemically modified by an etherification reaction. This treatment results in a differentiated pulp having improved physical, chemical and mechanical properties when compared with cellulose pulps obtained by traditional processes. The use of said biopolymer alters the relations between important pulp properties rendering their application in papermaking process advantageous. This differentiation increases the possibilities of use and also of new applications, including for the substitution of pulps produced from other cellulose sources. Thus, the present invention also relates to methods of making paper, such as printing, writing, decorative, special or tissue-type papers, through the use of the cellulose pulps modified by the above process.

A pulp mixture includes a lignocellulosic material, water, lignin, an inorganic salt, and a copolymer including two or more structural units chosen from ethylene oxide units, propylene oxide units, (meth)acrylic acid units, ethyl acrylate units, and combinations thereof. The copolymer is free of silicone-containing structural units and the lignin is present in an amount of greater than about 150 ppm, based on a total weight of the pulp mixture.

The present invention provides for a process for producing dry, water-dispersible, non-surface modified nanocellulose particles or a powderous composition r comprising said particles comprising the steps of: i. providing a first suspension of non-surface modified cellulose particles in an first aqueous liquid, which aqueous liquid is non-solubilizing for the non-surface modified nanocellulose particles, ii. exchanging substantially all of the first aqueous liquid of the first suspension for a second solvent, which is miscible with the first aqueous liquid and non-solubilizing for the non-surface modified nanocellulose particles, to form a second suspension of non-surface modified nanocellulose particles in said second solvent, iii. contacting a flow of the second suspension of non-surface modified nanocellulose particles with a flow of a fluid in a supercritical or critical state, which fluid in a supercritical or critical state is miscible with the second solvent and non-solvating for the non-surface modified nanocellulose particles under conditions suitable for the transfer of substantially all of the second solvent into the supercritical fluid, iv. removing the second solvent and the fluid in a supercritical or critical state, preferably by controlling pressure and/or temperature, to form the dry, water-dispersible nanocellulose particles, v. collecting the dry, water-dispersible, non-surface modified nanocellulose particles and/or forming the powderous composition comprising said particles.

The present invention relates to a process for the production of microfibrillated cellulose composition, wherein the microfibrillated cellulose has an average fiber length in the range from 500 to 1300 m and a percentage of fiber length in the category 200 m of at least 15%, obtained by subjecting an aqueous mixture comprising 30 to 70% by weight of cellulose containing fibers to mechanical shearing at a temperature in the range of from 40 C. to 120 C. in the presence of at least one thermostable biocide, to the microfibrillated cellulose composition obtained in this process and their use in a process for production of paper, card and board comprising draining a paper stock comprising the microfibrillated cellulose composition with sheet formation in the wire.

A process for the production of a non-derivatized nanocellulose material from a cellulosic fibrous material, comprising the steps of providing a suspension of cellulosic fibrous material in a continuous phase of a non-aqueous process liquid comprising a swelling agent and a processing solvent; forming a suspension of swollen cellulosic fibrous material in a continuous phase of non-aqueous process liquid; forming a suspension of cellulosic fibrous material in a continuous phase of processing solvent; forming a dispersion of non-derivatized nanocellulose material in a continuous phase of a processing solvent; isolating the non-derivatized nanocellulose material, characterized in that the swelling agent is a low-transition-temperature mixture (LTTM) and in particular a deep eutectic solvent and said low-transition-temperature mixture and in particular said deep eutectic solvent is soluble in the processing solvent and wherein the processing solvent is non-solubilizing for the cellulosic fibrous material and the non-derivatized nanocellulose material.