Nanocellulose compositions and processes to produce same
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 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.
1. A composition comprising hydrophobic, lignin-coated nanocellulose, wherein said nanocellulose contains about 0.5 wt % sulfur content or less.
2. The composition of claim 1 , wherein said nanocellulose contains about 0.1 wt % sulfur content or less.
3. The composition of claim 2 , wherein said nanocellulose contains no sulfur content.
4. The composition of claim 1 , wherein said nanocellulose contains about 0.5 wt % sodium content or less.
5. The composition of claim 1 , wherein said nanocellulose contains no chlorine content.
6. The composition of claim 1 , wherein said nanocellulose further contains calcium.
7. The composition of claim 1 , wherein said nanocellulose is in the form of cellulose nanocrystals and/or cellulose nanofibrils.
8. The composition of claim 1 , wherein said nanocellulose is characterized by a crystallinity of at least 80%.
9. The composition of claim 1 , wherein said nanocellulose is characterized by a crystallinity of at least 85%.
10. The composition of claim 9 , wherein said nanocellulose is characterized by a crystallinity of at least 90%.
11. The composition of claim 1 , wherein said nanocellulose is characterized by an onset of thermal decomposition of about 300° F. or higher.
12. The composition of claim 11 , wherein said nanocellulose is characterized by an onset of thermal decomposition of about 350° F. or higher.
13. The composition of claim 1 , wherein said nanocellulose is characterized by a transmittance of less than about 20% at a wavelength of 400 nm.
14. The composition of claim 13 , wherein said nanocellulose is characterized by a transmittance of less than about 5% at a wavelength of 400 nm.
15. The composition of claim 1 , wherein said nanocellulose is characterized by a transmittance of less than about 30% at a wavelength of 700 nm.
16. The composition of claim 15 , wherein said nanocellulose is characterized by a transmittance of less than about 10% at a wavelength of 700 nm.
17. A product comprising the nanocellulose composition of claim 1 .
18. The product of claim 17 , said product further comprising a material selected from the group consisting of a polymer, a carbon fiber, graphene, a glass, a solvent, a fluid, a substrate, and combinations thereof.