Nanocellulose-reinforced cellulose fibers

Abstract

Nanocellulose-reinforced cellulose fibers can increase the strength of hardwood fibers or agricultural-residue cellulose fibers, to simulate the strength of softwood fibers in pulp or pulp products (including composites). In some variations, the invention provides a method of reinforcing cellulose fibers, comprising providing cellulose fibers derived from hardwoods, agricultural residues, or a combination thereof; providing a source of nanocellulose comprising cellulose nanofibrils and/or cellulose nanocrystals; and reinforcing the cellulose fibers with the nanocellulose to increase strength of the cellulose fibers. In some embodiments, the nanocellulose is obtained from fractionating biomass in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid phase; and then mechanically refining the cellulose-rich solids to generate the nanocellulose.

What is claimed is: 
     
         1 . A method of reinforcing cellulose fibers, said method comprising:
 (a) providing cellulose fibers derived from hardwoods, agricultural residues, or a combination thereof;   (b) providing a source of nanocellulose comprising cellulose nanofibrils and/or cellulose nanocrystals; and   (c) reinforcing said cellulose fibers with said nanocellulose to increase strength of said cellulose fibers.   
     
     
         2 . The method of  claim 1 , wherein said nanocellulose is derived from a biomass source selected from the group consisting of hardwoods, softwoods, agricultural residues, and combinations thereof. 
     
     
         3 . The method of  claim 1 , wherein said nanocellulose is obtained from fractionating biomass in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid phase; and then mechanically refining said cellulose-rich solids to generate said nanocellulose. 
     
     
         4 . The method of  claim 3 , wherein said acid is sulfur dioxide and said solvent is ethanol. 
     
     
         5 . The method of  claim 1 , said method further comprising producing a single-fiber product from said cellulose fibers. 
     
     
         6 . The method of  claim 1 , said method further comprising producing a composite from said cellulose fibers. 
     
     
         7 . A composition comprising nanocellulose-reinforced hardwood cellulose fibers and/or nanocellulose-reinforced agricultural-residue cellulose fibers. 
     
     
         8 . The composition of  claim 7 , wherein said composition comprises said nanocellulose-reinforced hardwood cellulose fibers. 
     
     
         9 . The composition of  claim 8 , wherein said nanocellulose-reinforced hardwood cellulose fibers have higher strength than said hardwood cellulose fibers without said nanocellulose. 
     
     
         10 . The composition of  claim 7 , wherein said composition comprises said nanocellulose-reinforced agricultural-residue cellulose fibers. 
     
     
         11 . The composition of  claim 10 , wherein said nanocellulose-reinforced agricultural-residue cellulose fibers have higher strength than said agricultural-residue cellulose fibers without said nanocellulose. 
     
     
         12 . A composition comprising nanocellulose-reinforced cellulose fibers, wherein said composition is produced by a method comprising:
 (a) providing cellulose fibers derived from hardwoods, agricultural residues, or a combination thereof   (b) providing a source of nanocellulose comprising cellulose nanofibrils and/or cellulose nanocrystals; and   (c) reinforcing said cellulose fibers with said nanocellulose to increase strength of said cellulose fibers.   
     
     
         13 . The composition of  claim 12 , wherein said nanocellulose is derived from a biomass source selected from the group consisting of hardwoods, softwoods, agricultural residues, and combinations thereof. 
     
     
         14 . The composition of  claim 12 , wherein said nanocellulose is obtained from fractionating biomass in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid phase; and then mechanically refining said cellulose-rich solids to generate said nanocellulose. 
     
     
         15 . The composition of  claim 14 , wherein said acid is sulfur dioxide and said solvent is ethanol. 
     
     
         16 . The composition of  claim 12 , wherein said cellulose fibers are present in a single-fiber product. 
     
     
         17 . The composition of  claim 12 , wherein said cellulose fibers are present in a composite.