Nanolignocellulose compositions and processes to produce these compositions
Some variations provide a new nanolignocellulose composition comprising, on a bone-dry, ash-free, and acetyl-free basis, from 35 wt % to 80 wt % cellulose nanofibrils, cellulose microfibrils, or a combination thereof, from 15 wt % to 45 wt % lignin, and from 5 wt % to 20 wt % hemicelluloses. The hemicelluloses may contain xylan or mannan as the major component. Novel properties arise from the hemicellulose content that is intermediate between high hemicellulose content of raw biomass and low hemicellulose content of conventional nanocellulose. The nanolignocellulose composition is hydrophobic due to the presence of lignin. Processes for making and using the nanolignocellulose compositions are also described.
1. A process for producing a nanolignocellulose composition, said process comprising:
(a) providing a lignocellulosic biomass feedstock;
(b) digesting said feedstock with a reaction solution including steam and/or hot water in a digestor under effective reaction conditions to produce a digested stream containing cellulose-rich solids, hemicellulose oligomers, and lignin;
(c) washing said cellulose-rich solids to separate at least a portion of said hemicellulose oligomers and/or at least a portion of said lignin from said cellulose-rich solids;
(d) mechanically treating said cellulose-rich solids to form a nanolignocellulose composition, wherein said nanolignocellulose composition comprises, on a bone-dry, ash-free, and acetyl-free basis, from about 35 wt % to about 80 wt % cellulose nanofibrils, cellulose microfibrils, or a combination thereof, from about 15 wt % to about 45 wt % lignin, and from about 5 wt % to about 20 wt % hemicelluloses, and wherein concentration of said cellulose nanofibrils and/or said cellulose microfibrils is calculated on a lignin-free, hemicellulose-free basis; and
(e) recovering said nanolignocellulose composition,
wherein said nanolignocellulose composition is characterized by an average nanoparticle diameter from about 3 nanometers to 100 nanometers and an average nanoparticle length from about 100 nanometers to about 10 microns, and
wherein said nanolignocellulose composition is characterized by at least 99% filtration completion in less than 100 minutes.
2. The process of claim 1 , said process further comprising forming a pulp product or a paper product containing said nanolignocellulose composition.