# US 10,870,950 B2 · Controlled porosity structural material with nanocellulose fibers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,950 B2 - Document ID: US10870950B2 - Status: Granted - Kind: B2 - Application number: 16/086,988 - Filed: 2017-03-21 - Published: 2019-03-28 - Granted: 2020-12-22 - Earliest claimed: 2016-03-21 - Assignees: University of Maine System Board of Trustees - Applicants: University of Maine System Board of Trustees - Inventors: Michael Darin Mason; David Gregg Holomakoff; Muhammad Radowan Hossen - Web page: https://patentgrep.com/patent/US10870950B2 ## CPC - D21H 11/18: Highly hydrated, swollen or fibrillatable fibres - C08L 1/02: Cellulose; Modified cellulose - D21C 9/007: {by mechanical or physical means} - D21C 9/18: De-watering (de-watering in general F26B); {Elimination of cooking or pulp-treating liquors from the pulp}(D21C9/002, D21C9/02 take precedence; paper-making machines D21F; strainers in digesters D21C7/00; presses in general B30B) - D21H 17/25: Cellulose - D21H 17/67: Water-insoluble compounds, e.g. fillers, pigments - D21H 21/22: Agents rendering paper porous, absorbent or bulky - D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - D21C: PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR ## Abstract The present invention provides, inter alia, biocompatible porous structural materials made exclusively or almost exclusively from nanocellulose fibers (CNF), CNC, or bacterial cellulose, as well as processes for making and using provided compositions. Provided compositions may possess specifically tailored mechanical strength properties and have a design-controlled porosity that is homogeneous or graded, depending on the application. Provided compositions may be manufactured by the controlled dewatering of suspensions of CNF. In some embodiments, provided compositions may include a solids concentration of about 10% to about 95% by weight. Controlled water removal and pore homo- or heterogeneity may be accomplished by controlling capillary, hydrostatic and evaporative processes in the environment of a porous mold around the CNF slurry. A freeze drying or vacuum drying step may be used to complete the drying process, locking in the porous network structure resulting in a predetermined porosity (pore volume/total volume), and pore size distribution. ## Claims ### Claim 1 A method for fabricating a porous nanocellulose material comprising: placing an aqueous suspension comprising nanocellulose fibrils in contact with a first surface of a porous dewatering material; and removing at least a portion of the water in the aqueous suspension via capillary action thereby forming a porous nanocellulose material, wherein the removing step continues for at least 8 hours. ### Claim 2 (depends on 1) The method of claim 1, wherein the porous dewatering material comprises a hydrophilic surface. ### Claim 3 (depends on 1) The method of claim 1, wherein the aqueous suspension comprises between 1 wt % to 10 wt % nanocellulose solids. ### Claim 4 (depends on 1) The method of claim 1, wherein the rate of water removal is between 0.001 and 2.0 L/hr/20 L of starting aqueous suspension. ### Claim 5 (depends on 1) The method of claim 1, further comprising controlling at least one of pressure and temperature to control a rate of water removal from a second surface of the porous dewatering material until the porous nanocellulose material comprises 5 wt % to 95 wt % nanocellulose solids. ### Claim 6 (depends on 5) The method of claim 5, wherein the second surface of the porous dewatering material is opposite the first surface. ### Claim 7 (depends on 5) The method of claim 5, wherein the at least one of pressure and temperature are at least one of pressure and temperature at the second surface of the porous dewatering material. ### Claim 8 (depends on 5) The method of claim 5, wherein controlling the pressure comprises creating at least a partial vacuum. ### Claim 9 (depends on 1) The method claim 1, further comprising: separating the porous nanocellulose material from the first surface of the porous dewatering material; and further drying the porous nanocellulose material. ### Claim 10 (depends on 9) The method of claim 9, wherein the further drying results in a porous nanocellulose material comprising a nanocellulose solids content from 15 wt % to 95 wt %. ### Claim 11 (depends on 1) The method claim 1, further comprising: freezing remaining water in the porous nanocellulose material; and evaporating the frozen remaining water from the porous nanocellulose material. ### Claim 12 (depends on 1) The method of claim 1, wherein the rate of water removal is not constant during the removing step. ### Claim 13 (depends on 1) The method of claim 1, wherein the aqueous suspension comprises at least one additive. ### Claim 14 (depends on 13) The method of claim 13, wherein the additive is or comprises a nanomaterial or polymer. ### Claim 15 (depends on 14) The method of claim 14, wherein the nanomaterial is or comprises a nanoparticle, nanosphere, a nanostar, nanowire, and/or a nanorod. ### Claim 16 (depends on 15) The method of claim 15, wherein the nanoparticle comprises at least one metal or polymer. ### Claim 17 (depends on 16) The method of claim 16, wherein the at least one metal or polymer comprises at least one metal and the at least one metal comprises gold, silver, platinum, any ferromagnetic metal, titania, copper, or a combination thereof. ### Claim 18 (depends on 13) The method of claim 13, wherein the at least one additive is or comprises a mineral. ### Claim 19 (depends on 18) The method of claim 18, wherein the mineral is selected from hydroxyapatite, calcium phosphate, and combinations thereof. ### Claim 20 (depends on 1) The method of claim 1, further comprising: immersing the porous nanocellulose material in a second aqueous suspension comprising water and nanocellulose fibrils; and removing at least a portion of the water in the second aqueous suspension via capillary action thereby forming a second porous nanocellulose material, wherein the removing step continues for at least 8 hours. ### Claim 21 (depends on 20) The method of claim 20, wherein the porosity of the porous nanocellulose material and the second porous nanocellulose material are different.