The present disclosure generally relates to a scalable, green process for producing non-toxic, all-cellulose super absorbent hydrogels that form instantly after cross-linking. A super absorbent hydrogel can be produced by physical mixing of water-soluble carboxyalkyl polysaccharides such carboxymethyl cellulose and negatively-charged cellulose nanocrystals resulting in instantaneous gelation. Cellulose nanocrystals act as effective cross-linkers when physically mixed with carboxymethyl cellulose in an aqueous medium. The resulting hydrogel possesses excellent absorption properties, and has applications in a wide range of products from hygiene products to medical and industrial super absorbent products.

Processes disclosed are capable of converting biomass into high-crystallinity nanocellulose with surprisingly low mechanical energy input. In some variations, the process includes fractionating biomass with an acid (such as sulfur dioxide), a solvent (such as ethanol), and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin; and mechanically treating the cellulose-rich solids to form nanofibrils and/or nanocrystals. The crystallinity of the nanocellulose material may be 80% or higher, translating into good reinforcing properties for composites. The nanocellulose material may include nanofibrillated cellulose, nanocrystalline cellulose, or both. In some embodiments, the nanocellulose material is hydrophobic via deposition of some lignin onto the cellulose surface. Optionally, sugars derived from amorphous cellulose and hemicellulose may be separately fermented, such as to monomers for various polymers. These polymers may be combined with the nanocellulose to form completely renewable composites.

Processes disclosed are capable of converting biomass into high-crystallinity nanocellulose with surprisingly low mechanical energy input. In some variations, the process includes fractionating biomass with an acid (such as sulfur dioxide), a solvent (such as ethanol), and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin; and mechanically treating the cellulose-rich solids to form nanofibrils and/or nanocrystals. The crystallinity of the nanocellulose material may be 80% or higher, translating into good reinforcing properties for composites. The nanocellulose material may include nanofibrillated cellulose, nanocrystalline cellulose, or both. In some embodiments, the nanocellulose material is hydrophobic via deposition of some lignin onto the cellulose surface. Optionally, sugars derived from amorphous cellulose and hemicellulose may be separately fermented, such as to monomers for various polymers. These polymers may be combined with the nanocellulose to form completely renewable composites.

A composition comprising nanocellulose is disclosed, wherein the nanocellulose contains very low or essentially no sulfur content. The nanocellulose may be in the form of cellulose nanocrystals, cellulose nanofibrils, or both. The nanocellulose is characterized by a crystallinity of at least 80%, an onset of thermal decomposition of 300° F. or higher, and a low light transmittance over the range 400-700 nm. Other variations provide a composition comprising lignin-coated hydrophobic nanocellulose, wherein the nanocellulose contains very low or essentially no sulfur content. Some variations provide a composition comprising nanocellulose, wherein the nanocellulose contains about 0.1 wt % equivalent sulfur content, or less, as SO.sub.4 groups chemically or physically bound to the nanocellulose. In some embodiments, the nanocellulose contains essentially no hydrogen atoms (apart from hydrogen structurally contained in nanocellulose itself) bound to the nanocellulose. Various compositions, materials, and products may incorporate the nanocellulose compositions disclosed herein.

A composition comprising nanocellulose is disclosed, wherein the nanocellulose contains very low or essentially no sulfur content. The nanocellulose may be in the form of cellulose nanocrystals, cellulose nanofibrils, or both. The nanocellulose is characterized by a crystallinity of at least 80%, an onset of thermal decomposition of 300° F. or higher, and a low light transmittance over the range 400-700 nm. Other variations provide a composition comprising lignin-coated hydrophobic nanocellulose, wherein the nanocellulose contains very low or essentially no sulfur content. Some variations provide a composition comprising nanocellulose, wherein the nanocellulose contains about 0.1 wt % equivalent sulfur content, or less, as SO.sub.4 groups chemically or physically bound to the nanocellulose. In some embodiments, the nanocellulose contains essentially no hydrogen atoms (apart from hydrogen structurally contained in nanocellulose itself) bound to the nanocellulose. Various compositions, materials, and products may incorporate the nanocellulose compositions disclosed herein.

The present invention provides crosslinked carboxymethylcellulose having high elastic modulus coupled with high absorbance capacity when swollen in simulated gastric fluid/water (1:8) and simulated intestinal fluids. The invention further provides methods of making the crosslinked carboxymethylcellulose, compositions comprising the crosslinked carboxymethylcellulose and methods of using the crosslinked carboxymethylcellulose, for example, for treating overweight or obesity or for enhancing glycemic control.

Provided is microcrystalline cellulose (MCC) from cellulosic or lignocellulosic biomass produced efficiently and quickly through cost-effective methods and systems. The MCC is comprised of short fibers due to the process through which the biomass is subjected. In addition to MCC, nanocellulose (CNF), and high quality crystalline nanocellulose (CNC) can be produced, as well as other cellulosic compounds, clean lignin and monomeric C5 and C6 sugars.

Disclosed herein is a polysaccharide aerogel comprising cotton cellulose fibres and a method of preparing the polysaccharide aerogel. The method comprises: mixing cotton cellulose fibres and a cross-linker to form a mixture; sonicating the mixture; freezing the sonicated mixture; and freeze drying the frozen mixture to form an aerogel. A further embodiment provides a polysaccharide aerogel comprising cotton cellulose fibres and paper cellulose fibres in a weight ratio of 1:1 to 1:6 and a method of preparation thereof wherein in the mixing step, the paper cellulose fibres are added to the cotton cellulose fibres to form a mixture.

A method for 3D printing is provided, using crosslinkable microfibrillated cellulose (MFC). The 3D printed structure is treated to provide crosslinking of the MFC.

A process for dissolving modified cellulose includes contacting modified cellulose solution with at least one multivalent cation to form a plurality of modified cellulose particles.