Methods and compositions for upcycling wool

Abstract

The present invention provides methods of preparing a keratin-rich gel from keratin-rich wool fiber and uses thereof in biocomposite applications.

Description

Atorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 TITLE METHODS AND COMPOSITIONS FOR UPCYCLING WOOLRELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Application No.63 / 743,622, filed on January 10, 2025, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION

[0002] In recent years, the wool industry has been scrutinized for its detrimental environmental effects due to its relationship to fast fashion [T. Smith, et al., “Rethinking the (Wool) Economy,” in Local, Slow and Sustainable Fashion; I. G. Klepp et al., Eds., Cham: Springer International Publishing, 2022, pp. 133-170] and the meat industry [M. J. Rivero et al., “A perspective on animal welfare of grazing ruminants and its relationship with sustainability,” Anim. Prod. Sci., vol. 62, no. 18, pp. 1739-1748, Feb. 2022], as well as its contribution to global deforestation and biodiversity loss through sheep-grazing [S. Feldstein, et al., “Shear Destruction: Wool, Fashion, and the Biodiversity Crisis,” Center for Biological Diversity, Collective Fashion Justice, Nov. 2021], Small ruminants, including sheep and goats, are responsible for nearly 500 million metric tons of CO2 annually [C. Opio et al., Greenhouse gas emissions from ruminant supply chains - a global life cycle assessment. Rome: Food and Agriculture Organization of the United Nations, 2013], Moreover, wool textiles undergo carbon- and chemical-intensive processing to remove impurities and agrochemical contamination, resulting in high effluent levels and environmental damage [S. Feldstein, et al., “Shear Destruction: Wool, Fashion, and the Biodiversity Crisis,” Center for Biological Diversity, Collective Fashion Justice, Nov. 2021],

[0003] Despite the wool production chain’s considerable carbon footprint, sheep grazing remains an essential part of the global economy. In 2019, the global sheep population grew to 1.18 billion, a 30-million increase from 2018, producing 1.15 million kilograms of wool [S. Feldstein, et al., “Shear Destruction: Wool, Fashion, and the Biodiversity Crisis,” Center for Biological Diversity, Collective Fashion Justice, Nov. 2021], However, demand for wool in the fashion industry has declined since the 1990s due to increased competition from synthetic and plant-based fibers, limited market expansion, and rising production costs [G. R. Gowane, et al., “Climate Change Impact on Sheep Production: Growth, Milk, Wool, and Meat,” in1MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 Sheep Production Adapting to Climate Change; V. Sejian et al. Singapore: Springer, 2017, pp. 31-69], By 2020, global wool production dropped to its lowest level in 50 years, with a 4-6% year-over-year decline [S. Feldstein, et al., “Shear Destruction: Wool, Fashion, and the Biodiversity Crisis,” Center for Biological Diversity, Collective Fashion Justice, Nov. 2021], Due to this supply-demand imbalance in the fashion industry and the limitations imposed by wool grades and lengths suitable for textiles, a significant portion of wool — up to 95% — is entering waste streams. Given the costs and challenges of adequately disposing of unmarketable wool, many farmers resort to illegal dumping or burning shorn wool without permits, further exacerbating environmental harm and potential health risks [H. Rajabinejad, I. et al., “Current Approaches For Raw Wool Waste Management And Unconventional Valorization: A Review,” Environ. Eng. Manag. J., vol. 18, no. 7, pp. 1439-1456, 2019],

[0004] Global sheep wool production remains substantial, with approximately 1,950 million kg produced annually from 1.2 billion sheep worldwide in 2021 [T. Smith, et al., “Rethinking the (Wool) Economy,” in Local, Slow and Sustainable Fashion; I. G. Klepp et al., Eds., Cham: Springer International Publishing, 2022, pp. 133-170], However, only ~ 60% is used in woolen fabric apparel manufacturing [M. J. Rivero et al., Anim. Prod. Sci., vol. 62, no. 18, pp. 1739-1748, Feb. 2022], In several regions, the majority of wool is wasted: 55% in parts of Canada [S. Feldstein, et al., “Shear Destruction: Wool, Fashion, and the Biodiversity Crisis,” Center for Biological Diversity, Collective Fashion Justice, Nov. 2021], 75% in Europe [C. Opio et al., Greenhouse gas emissions from ruminant supply chains - a global life cycle assessment. Rome: Food and Agriculture Organization of the United Nations, 2013], and 95% of Italy’s 14 million kg of annual production does not find cost-effective applications [G. R. Gowane, et al., “Climate Change Impact on Sheep Production: Growth, Milk, Wool, and Meat,” in Sheep Production Adapting to Climate Change; V. Sejian et al. Singapore: Springer, 2017, pp. 31-69], This surplus continues to be primarily driven by fiber length, strength, and grading criteria, where fine-grade fibers are suitable for textiles, while medium and coarse grades have limited market demand [M. J. Rivero et al., Anim. Prod. Sci., vol. 62, no. 18, pp. 1739-1748, Feb. 2022], Fine wool accounted for about 40% of 2023 production [H. Rajabinejad, et al., Environ. Eng. Manag. J., vol. 18, no. 7, pp. 1439-1456, 2019], The collapse of wool reserve price schemes in major wool-producing countries such as Australia, New Zealand, and South Africa has further destabilized the market [T.-O. Denes et al., “Analysis of Sheep Wool-Based Composites for Building Insulation,” Polymers, vol. 14, no. 10, p. 2109, May 2022; O. Denes, et al., “Utilization of Sheep Wool as a Building2MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 Material,” ProcediaManuf., vol. 32, pp. 236-241, 2019], In Europe and North America, shearing costs now exceed raw wool prices [S. Feldstein, et al., “Shear Destruction: Wool, Fashion, and the Biodiversity Crisis,” Center for Biological Diversity, Collective Fashion Justice, Nov. 2021; C. Gaidau et al., “Wool keratin total solubilisation for recovery and reintegration - An ecological approach,” J. Clean. Prod., vol. 236, p. 117586, Nov. 2019], with Irish prices as low as €0.15 per kg versus shearing costs of €2.40 per head [L. Cera et al., “A bioinspired and hierarchically structured shape-memory material,” Nat. Mater., vol.20, no. 2, pp. 242-249, Feb. 2021], As a result, farmers have transitioned to dual-purpose breeds that provide both meat and wool to remain economically viable [M. J. Rivero et al., Anim. Prod. Sci., vol. 62, no. 18, pp. 1739-1748, Feb. 2022], Accumulated unsellable wool creates additional challenges, including illegal disposal or burning, and potential environmental hazards from high bacterial content [P. Bhavsar, et al., “Sustainably Processed Waste Wool Fiber-Reinforced Biocomposites for Agriculture and Packaging Applications,” Fibers, vol. 9, no. 9, p. 55, Sep. 2021; V. Guna et al., “Engineering Sustainable Waste Wool Biocomposites with High Flame Resistance and Noise Insulation for Green Building and Automotive Applications,” J. Nat. Fibers, vol. 18, no. 11, pp. 1871-1881, Nov. 2021],

[0005] Within this context, efforts to develop alternative uses for otherwise unusable raw wool fibers are increasingly critical. These valorization methods fall into three primary pathways: (1) applications that utilize wool’s inherent properties, such as felting [T.-O. Denes et al., Polymers, vol. 14, no. 10, p. 2109, May 2022], moisture absorption [H. Rajabinejad, et al., Environ. Eng. Manag. J., vol. 18, no. 7, pp. 1439-1456, 2019], and fiber reinforcement in concrete [O. Denes, et al., Procedia Manuf. , vol. 32, pp. 236-241, 2019]; (2) applications that harness the keratin protein biopolymer, such as powderization and blending with chitosan to create a biodegradable thermoplastic [H. Rajabinejad, et al., Environ. Eng. Manag. J., vol. 18, no. 7, pp. 1439-1456, 2019], keratin solubilization for agricultural reintegration [C. Gaidau et al., J. Clean. Prod., vol. 236, p. 117586, Nov. 2019], generation of new keratin fibers [L. Cera et al., Nat. Mater., vol. 20, no. 2, pp. 242-249, Feb. 2021], and packaging applications [P. Bhavsar, et al., Fibers, vol. 9, no. 9, p. 55, Sep. 2021]; and (3) applications that integrate raw wool within a biocomposite, such as combining wool with acrylic-polyurethane resin and natural rubber latex [T.-O. Denes et al., Polymers, vol. 14, no. 10, p. 2109, May 2022], polypropylene [V. Guna et al., “Engineering Sustainable Waste Wool Biocomposites with High Flame Resistance and Noise Insulation for Green Building and Automotive Applications,” J. Nat. Fibers, vol. 18, no. 11, pp. 1871-1881, Nov. 2021; M. Ilangovan et al.,3MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 “Hybrid biocomposites with high thermal and noise insulation from discarded wool, poultry feathers, and their blends,” Constr. Build. Mater., vol. 345, p. 128324, Aug. 2022], or alkaline sodas for commercial products [R. Pennacchio et al., “FITNESs: Sheep-wool and Hemp Sustainable Insulation Panels,” Energy Procedia, vol. Ill, pp. 287-297, Mar. 2017], While these methods offer potential solutions, many require additional materials — often hydrocarbon-based — that feed into a problematic petrochemical plastic system [A. Borunda, “California sues ExxonMobil for misleading public on plastic recycling,” NPR, Sep. 23, 2024. https: / / www.npr.org / 2024 / 09 / 23 / nx-sl-5123619 / california-sues-exxonmobil-for-misleading-public-on-plastic-recy cling],

[0006] As anthropogenic carbon emissions continue to increase global average temperatures, the building sector — accounting for approximately 42% of all energy usage, 65% of which is used for thermal conditioning (26% of global emissions) — has come under scrutiny [“Buildings - Energy System,” IEA. https: / / www.iea.org / energy-system / buildings; S. Hetimy, et al., “Exploring the potential of sheep wool as an eco-friendly insulation material: A comprehensive review and analytical ranking,” Sustain. Mater. Technol., vol. 39, p. e00812, Apr. 2024], In response, rigorous policies and certification programs have been implemented to reduce energy consumption in new construction. Recently, policies have also begun addressing energy efficiency improvements in the existing building stock [“Building Energy Code; https: / / www.mass.gov / info-details / building-energy-code]. However, a crucial question remains: How can we achieve building-energy reductions without increasing the production of carbon-intensive, fossil fuel-derived foam insulations (and without F-gases) [B. Benke, et al., “The California Carbon Report: An Analysis of the Embodied and Operational Carbon Impacts of 30 Buildings,” Carbon Leadership Forum, University of Washington, Seattle, WA, 2024; A. Korjenic, et al., “Sheep Wool as a Construction Material for Energy Efficiency Improvement,” Energies, vol. 8, no. 6, pp. 5765-5781, Jun. 2015]?

[0007] Thus, there is a need to develop high-performance insulation materials that are stiff and low-water absorbing and leverage natural fibers, such as sheep wool, towards a sustainable solution for healthy, low-operational-energy, and low-embodied-carbon building materials.SUMMARY OF THE INVENTION

[0008] In one aspect, the present invention provides a method for preparing a keratin-rich gel comprising: (a) providing a keratin-rich wool fiber; (b) trimming the keratin-rich wool fiber into strands to obtain a trimmed wool fiber; (c) treating the trimmed wool fiber with an4MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 alkaline solution at about 60 °C for about 24 hours to obtain a hydrolyzed wool fiber; (d) rinsing the hydrolyzed wool fiber with deionized or distilled water to a neutral pH of about 6.5 to about 7.5 to obtain a rinsed wool fiber; (e) immersing the rinsed wool fiber in deionized or distilled water and mechanically blending and / or sonicating the immersed wool fiber for at least 5 minutes to obtain a milky aqueous solution; (f) separating the milky aqueous solution to obtain a residual fiber and an aqueous solution containing microfibrils; and (g) centrifuging the aqueous solution containing microfibrils for at least 30 minutes to obtain a keratin-rich gel.

[0009] The keratin-rich wool fiber may be selected from hair, feather, wool-based textile, or a combination thereof. In one embodiment, the hair is animal hair and the animal hair is wool. The wool may be selected from the group consisting of sheep wool, goat wool, alpaca wool, bison wool and rabbit wool. In one aspect, the wool is sheep wool. The keratin-rich wool fiber comprises of alpha-keratin, beta-keratin, or a combination thereof. The strands in step (b) may be about 10 microns to about 100 microns in size. In other embodiment, the strands in step (b) may be about 0.5 cm to about 1 cm in size. The alkaline solution in step (c) may be an aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, and ammonia, and combinations thereof. The concentration of the alkaline solution in step (c) may be about 0.04 N, about 0.06 N, about 0.08 N, about 0.1 N, about 0.12 N, about 0.14 N, about 0.16 N, or about 0.2 N. In one aspect, the alkaline solution in step (c) is an aqueous solution comprising about 0.1 N sodium hydroxide. Separating the milky aqueous solution in step (f) is achieved by filtration, sedimentation, electrostatic precipitation, addition of coagulants, addition of flocculants, or a combination thereof. The keratin-rich gel is biocompatible and biodegradable.

[0010] In one aspect, the present invention provides a method of making a biopolymer film, the method comprising: (1) providing the keratin-rich gel prepared as described herein; (2) mixing the keratin-rich gel with a solution comprising about 0.1% to about 100% wt of a chemical cross-linker to obtain a mixture; and (3) subjecting the mixture in a mold, followed by curing to obtain a biopolymer film. In this method, an anti-foaming agent is optionally added to the mixture obtained from step (2). The anti-foaming agent may be a mineral oil or a surfactant. Subjecting the mixture in a mold in step (3) may be performed by casting, extruding, sprayingjetting, injecting, or a combination thereof. The chemical cross-linker in step (2) may be selected from the group consisting of citric acid, glycolic acid, lactic acid,5MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0011] In one aspect, the present invention provides a method of making a fiberboard, the method comprising: (1) providing the residual fiber prepared as described herein; and (2) compressing the residual fiber to obtain a fiberboard. The compressing in step (2) of this method may be performed with a hydraulic press, a hydraulic heat press, mechanical press, or mechanical heat press. The fiberboard obtained from this method may be low-density fiberboard (LDF), medium-density fiberboard (MDF), or high-density fiberboard (HDF).

[0012] In one aspect, the present invention provides a method of making a fiberboard, the method comprising: (1) providing the residual fiber prepared as described herein; (2) providing raw unprocessed wool fiber; and (3) combining via mechanical homogenization and compressing the residual fiber and the raw unprocessed wool fiber to obtain a fiberboard. The compressing in step (2) of this method may be performed with a hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press. The fiberboard obtained from this method may be low-density fiberboard (LDF), medium-density fiberboard (MDF), or high-density fiberboard (HDF).

[0013] In one aspect, the present invention provides a method of making a composite fiberboard, the method comprising: (1) providing the keratin-rich gel prepared as described herein; (2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture; (3) providing the residual fiber prepared as described herein; and (4) adding the residual fiber to the mixture, followed by compressing to obtain a composite fiberboard. The compressing in step (4) of this method may be performed with a hydraulic press, a hydraulic heat press, mechanical press, or mechanical heat press. The chemical cross-linker in step (2) may be selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid. The ratio of the keratin-rich gel to the residual fiber may be from about 0: 1 to about 1:0. In one embodiment, increasing the ratio of the keratin-rich gel to the residual fiber decreases porosity and water absorption of the composite fiberboard. In one embodiment, the ratio of the chemical cross-linker to the keratin-rich gel is from about 0: 1 to about 1 : 1. In one aspect, increasing the ratio of the chemical cross-linker to the keratin-rich gel improves mechanical strength of the composite fiberboard.6MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0014] In one aspect, the present invention provides a method of making a coated fiberboard, the method comprising: (1) providing the residual fiber prepared as described herein; (2) compressing the residual fiber to obtain a fiberboard; (3) providing the keratin-rich gel prepared as described herein; and (4) coating the fiberboard with the keratin-rich gel, followed by curing to a obtain a coated fiberboard. The compressing in step (2) of this method may be performed with a hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press. The coating in step (4) of this method is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

[0015] In one aspect, the present invention provides a method of making a coated composite fiberboard, the method comprising: (1) providing the keratin-rich gel prepared as described herein; (2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture; (3) providing the residual fiber as described herein; (4) adding the residual fiber to the mixture, followed by compressing to obtain a composite fiberboard; and (5) coating the composite fiberboard with the keratin-rich gel, followed by curing to obtain a coated composite fiberboard. The compressing in step (4) of this method may be performed with a hydraulic press, a hydraulic heat press, mechanical press, or mechanical heat press. The coating in step (5) of this method may be achieved by spraying, dipping, painting, roll coating, or a combination thereof. The chemical cross-linker in step (2) may be selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0016] In one aspect, the present invention provides a method of making a coated composite fiberboard, the method comprising: (1) providing the keratin-rich gel as described herein; (2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture; (3) providing the residual fiber prepared as described herein; (4) adding the residual fiber to the mixture, followed by compressing to obtain a composite fiberboard; and (5) coating the composite fiberboard with the mixture from step (2), followed by curing to obtain a coated composite fiberboard. The compressing in step (4) of this method of this method may be performed with a hydraulic press, a hydraulic heat press, mechanical press, or mechanical heat press. The coating in step (5) of this method may be achieved by spraying, dipping, painting, roll coating, or a combination thereof. The chemical cross-linker in step (2) may be selected from the group consisting of7MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some aspects, the chemical cross-linker is citric acid.

[0017] In one aspect, the present invention provides a method of making a coated felt or a coated wool textile, the method comprising: (1) providing the keratin-rich gel prepared as described herein; (2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture; (3) providing a felt or a wool textile; and (4) coating the felt or the wool textile with the keratin-rich gel, followed by curing to obtain a coated felt or a coated wool textile. The coating in step (4) of this method may be achieved by spraying, dipping, painting, roll coating, or a combination thereof. The chemical cross-linker in step (2) may be selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0018] In one aspect, the present invention provides a method of making a coated felt or a coated wool textile, the method comprising: (1) providing the keratin-rich gel prepared as described herein; (2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture; (3) providing a felt or a wool textile; and (4) coating the felt or the wool textile with the mixture from step (2), followed by curing to obtain a coated felt or a coated wool textile. The coating in step (4) of this method may be achieved by spraying, dipping, painting, roll coating, or a combination thereof. The chemical cross-linker in step (2) may be selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0019] In one aspect, the present invention provides a method of making a coated felt or a coated wool textile, the method comprising: (1) providing the keratin-rich gel prepared as described herein; (2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture; (3) providing a felt or a wool textile; (4) treating the felt or the wool textile with an alkaline solution at about 60 °C for about 24 hours to obtain a hydrolyzed felt or a hydrolyzed wool textile; (5) rinsing the hydrolyzed felt or the hydrolyzed wool textile with deionized or distilled water to a neutral pH of about 6.5 to about 7.5 and obtain a rinsed felt or a rinsed wool textile; and (6) coating the rinsed felt or the rinsed wool textile with the mixture from step (2), followed by curing to obtain a coated felt or a coated wool textile. The coating in step (6) of this method may be achieved by spraying, dipping, painting, roll coating, or a combination thereof. The chemical8MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 cross-linker in step (2) may be selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid. The alkaline solution in step (4) may be an aqueous solution of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium sulfide, or ammonia, or a combination thereof. The concentration of the alkaline solution in step (4) may be about 0.04 N, about 0.06 N, about 0.08 N, about 0.1 N, about 0.12 N, about 0.14 N, about 0.16 N, or about 0.2 N. The alkaline solution in step (4) may be an aqueous solution comprising about 0.1 N sodium hydroxide.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. l is a schematic of general methodology of steps involved in preparing a keratin-rich gel from wool fibers.

[0021] FIG. 2 shows the preparation of keratin-rich gel. FIG. 2A is a picture showing alkaline treatment of wool fibers. FIG. 2B is a picture showing aqueous dispersion. FIG. 2C is a picture of residual fibers separated from the aqueous solution. FIG. 2D is a picture of keratin-rich gel.

[0022] FIG. 3 is a Scanning Electron Microscopy (SEM) image of wool fiber and keratin-rich gel. FIG. 3 A is a SEM image of scoured, unprocessed wool fiber (scale bar = 5 pm). FIG.3B is a SEM image of Wool fiber after 24h alkaline treatment (scale bar = 5 pm). FIG. 3C is a SEM image of keratin-rich gel with microfibrils (scale bar = 5 pm). FIG. 3D is a SEM image of keratin-based film (scale bar = 1 pm).

[0023] FIG. 4 is a schematic of applications of keratin-rich gel.

[0024] FIG. 5 shows applications of keratin-rich gel. FIG. 5 A is a picture showing keratin biopolymer film plasticized with citric acid. FIG. 5B is a of a fiberboard made with processed residual fibers. FIG. 5C is a picture of a composite fiberboard made with keratin biopolymer and processed residual fibers. FIG. 5D is a picture of a composite fiberboard coated with keratin biopolymer film. FIG. 5D is a picture showing a wool felt coated with keratin biopolymer film.

[0025] FIG. 6 depicts mechanical characterization testing of composite fiberboard (COMP), the keratin-rich gel and PDMS control. FIG. 6A shows the tensile testing of keratin-rich polymer film. FIG. 6B shows early results for COMP, keratin-rich gel, and PDMS control showing increased stiffness in the COMP compared to the keratin-rich gel and PDMS control. Standard error is shown for n = 3 samples (nCOMP = 1).9MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0026] FIG. 7 shows heat pressed keratin-rich gel composite samples. FIG. 7A shows residual fibers compressed with hydraulic heat press. FIG. 7B shows a picture of a fiberboard, heat pressed. FIG. 7C shows a picture of a keratin-rich gel composite fiberboard with citric acid, heat pressed. FIG. 7D shows a picture of a keratin-rich gel composite fiberboard with calcium chloride, heat pressed.

[0027] FIG. 8 shows preparation of wool biocomposite fiberboards. FIG. 8A shows the acrylic mold for cold-pressing. FIG. 8B shows cold-pressing. FIG. 8C shows cold-pressed wool panels for pre-drying. FIG. 8D shows aluminum mold for heat-pressing. FIG. 8E shows heat-pressing.

[0028] FIG. 9A shows examples of bending wool biocomposite fiberboard test samples Al-A6 as described in Table 1. FIG. 9B shows heat-pressed wool biocomposite fiberboard. FIG. 9C shows CNC-milling of wool biocomposite panel.

[0029] FIG. 10 shows the full scale prototype of wool biocomposite panel cladding system.

[0030] FIG. 11 shows the FTIR spectra and peak intensity ratios of wool films. FIG. 11 A is a FTIR spectra of (a) wool film, 0% citric acid; (b) wool film, 10% citric acid; (c) wool film, 20% citric acid; (d) wool film, 30% citric acid; and citric acid. FIG. 1 IB shows the corresponding peak intensities at 1716 cm'1of (a) wool film, 0% citric acid; (b) wool film, 10% citric acid; (c) wool film, 20% citric acid; and (d) wool film, 30% citric acid (compared over 1647 cm'1peak).

[0031] FIG. 12 shows the FTIR spectra and peak intensity ratios of wool fiber composites. FIG. 12A is a FTIR spectra of (a) biocomposite fiberboard specimen Al, 150 °C; (b) biocomposite fiberboard specimen A4 120 °C; (c) biocomposite fiberboard specimen A4 150 °C; (d) biocomposite fiberboard specimen A4 180 °C, and citric acid. FIG. 12B shows the corresponding peak intensities at 1710 cm'1of (a) biocomposite fiberboard specimen Al, 150 °C; (b) biocomposite fiberboard specimen A4 120 °C; (c) biocomposite fiberboard specimen A4 150 °C; and (d) biocomposite fiberboard specimen A4 180 °C (compared over 1647 cm'1peak).

[0032] FIG. 13 depicts the 3-pointbend test of biocomposite fiberboard, A1-A6 specimen and B3-B4 specimen. FIG. 13A shows instron testing of biocomposite fiberboard. FIG. 13B shows the dimensions of A1-A6 specimen. FIG. 13C shows the dimensions of B3-B4 specimen.10MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0033] FIG. 14 is a graph showing flexural moduli of (a) MDF 3.175 mm thick, low range (n=3); (b) MDF 6.35 mm thick, high range (n=3); (c) wool biocomposite specimen A4, 150 °C (n=5); and (d) wool biocomposite+wool specimen B4, 150 °C (n=3).

[0034] FIG. 15 depicts the thermal conductivity measurement device and its components. FIG. 15A shows the apparatus set up for guarded hot plate. FIG. 15B is a diagram showing composition of device and placement of thermocouples.

[0035] FIG. 16 is a graph showing thermal conductivity of (a) EPS foam; (b) MDF 6.35 mm thick, high range (n=3); and (c) wool biocomposite+wool specimen B4, 150 °C (n=3).

[0036] FIG. 17 shows the Global warming potential (GWP) for (a) EPS Foam, BC excluded; (b) EPS Foam, BC included; (c) MDF, BC excluded; (d) MDF, BC included; (e) Wool panel, raw wool, BC excluded; (f) Wool panel, raw wool, BC included; (g) Wool panel, waste wool, BC excluded; and (f) Wool panel, waste wool, BC included. FIG. 17A is a graph showing GWP per kg of material. FIG. 17B is a graph showing GWP with material thickness matching RSI values. Biogenic Carbon content is noted as “BC.” Wool data use SimaPro with Ecoinvent V.3 and TRACI 2.1 VI .09 / US 2008 GWP Method. EPS data use EPDs.

[0037] FIG. 18 shows the water absorption of MDF, Al, A4, B4, A7, A8, and A10 biocomposite samples after (a) 2 hours and (b) 24 hours.

[0038] FIG. 19 shows preliminary fire tests (left) cleaned wool, (center) wool fiber composite, and (right) medium-density fiberboard.

[0039] FIG. 20 shows mechanical tests of MDF and wool biocomposite fiberboard specimens A1-A6 as described in Table 1 at 120 °C, 150 °C, and 180 °C. FIG. 20A is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimens Al-A6 at 120 °C. FIG. 20B is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimens A1-A6 at 150 °C. FIG. 20C is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimens A1-A6 at 180 °C.

[0040] FIG. 21 shows mechanical tests of MDF and wool biocomposite fiberboard specimens A1-A3 as described in Table 1 at 120 °C, 150 °C, and 180 °C. FIG. 21A is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen Al at 120 °C, 150 °C, and 180 °C. FIG. 21B is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A2 at 120 °C, 150 °C, and 180 °C. FIG.21C is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A3 at 120 °C, 150 °C, and 180 °C.11MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0041] FIG. 22 shows mechanical tests of MDF and wool biocomposite fiberboard specimens A4-A6 as described in Table 1 at 120 °C, 150 °C, and 180 °C. FIG. 22A is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A4 at 120 °C, 150 °C, and 180 °C. FIG. 22B is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A5 at 120 °C, 150 °C, and 180 °C. FIG.22C is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A6 at 120 °C, 150 °C, and 180 °C.

[0042] FIG. 23 is a graph showing flexural moduli of (a) MDF 3.175 mm thick, low range (n=3); (b) wool biocomposite fiberboard specimen Al at 120 °C; (c) wool biocomposite fiberboard specimen Al at 150 °C; (d) wool biocomposite fiberboard specimen Al at 180 °C; (e) wool biocomposite fiberboard specimen A2 at 120 °C; (f) wool biocomposite fiberboard specimen A2 at 150 °C; (g) wool biocomposite fiberboard specimen A2 at 180 °C; (h) wool biocomposite fiberboard specimen A3 at 120 °C; (i) wool biocomposite fiberboard specimen A3 at 150 °C; (j) wool biocomposite fiberboard specimen A3 at 180 °C; (k) wool biocomposite fiberboard specimen A4 at 120 °C; (1) wool biocomposite fiberboard specimen A4 at 150 °C; (m) wool biocomposite fiberboard specimen A4 at 180 °C; (n) wool biocomposite fiberboard specimen 5 at 120 °C; (o) wool biocomposite fiberboard specimen A5 at 150 °C; (p) wool biocomposite fiberboard specimen A5 at 180 °C; (q) wool biocomposite fiberboard specimen A6 at 120 °C; (r) wool biocomposite fiberboard specimen A6 at 150 °C; and (s) wool biocomposite fiberboard specimen A6 at 180 °C.

[0043] FIG. 24 is a conceptual diagram of a retrofittable upcycle wool panel system.

[0044] FIG. 25 is a prototype assembly of the bi-layer design. FIG. 25A is a picture of the exterior and interior layers of the composite panel. FIG. 25B is a picture of the assembled composite panel showing the interior layer side. FIG. 25C is a picture of the assembled composite panel showing the exterior layer side.DETAILED DESCRIPTION

[0045] Exemplary embodiments of the present disclosure are illustrated in the drawings, which are illustrative rather than restrictive. No limitation on the scope of the technology, or on the claims that follow, is to be implied or inferred from the examples shown in the drawings and discussed herein.

[0046] The present invention provides both macro- and micro-scale material transformations taken upon waste wool to produce a standardized, durable, non-toxic, highly-insulative panel that can provide deep energy retrofits at scale and aid in national regenerative grazing efforts.12MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 Biocomposite materials explored in such transformations were studied for their carbon intensity and possible carbon-storing capacity throughout their entire life cycle and material ecology. Resulting products may take the form of an insulation panel clipped to the exterior of existing buildings and algorithmically designed to fit any building shape, a process being developed by Boston-based Highland Park Technologies using panels made of compressed wood fiber board.

[0047] Current Methods of Wool Valorization: Whole Fibers and Keratin Extraction:

[0048] Research on upcycling waste wool includes using natural fiber properties or keratin protein recovery through solubilization [H. Rajabinejad, et al., “Current Approaches For Raw Wool Waste Management And Unconventional Valorization: A Review,” Environ. Eng. Manag. J., vol. 18, no. 7, pp. 1439-1456, 2019], Raw sheep wool is composed of -60% protein fibers (primarily keratin), 15% moisture, 10% fat, 10% sweat, and 5% impurities [J. Zach, et al., “Performance evaluation and research of alternative thermal insulations based on sheep wool,” Energy and Buildings, vol. 49, pp. 246-253, June 2012], The wool fiber consists of an outer hydrophobic lipid layer and overlapping cuticular cells responsible for felting behavior and shrinkage tendencies; beneath is the cortex (-85% of the fiber mass) and medulla (in coarse fibers), whose air-filled intercellular spaces contribute to the fiber’s high insulating properties [S. G. Giteru, et al., “Wool keratin as a novel alternative protein: A comprehensive review of extraction, purification, nutrition, safety, and food applications,” Comprehensive Reviews in Food Science and Food Safety, vol. 22, no. 1, pp. 643-687, 2023], Upcycling applications include thermal and acoustical insulation, fiber reinforcement in composites, sorbents to treat contaminated air / water, and organic fertilizers [H.Rajabinejad, et al., Environ. Eng. Manag. J., vol. 18, no. 7, pp. 1439-1456, 2019],

[0049] Keratin is the primary protein in wool, comprising up to 90-95% by weight [J. M. Cardamone, et al., “Characterizing Wool Keratin,” Advances in Materials Science and Engineering, vol. 2009, no. 1, p. 147175, 2009], Keratin’s polypeptide structure is stabilized by various chemical interactions, including hydrogen bonds, ionic bonds, disulfide bridges, and hydrophobic interactions [N. Senthilkumar, et al., “Extraction of keratin from keratinous wastes: current status and future directions,” J Mater Cycles Waste Manag, vol. 25, no. 1, pp.1-16, Jan. 2023], Its self-assembling molecular architecture makes it a promising candidate for biopolymer applications [C. R. Chilakamarry et al., “Extraction and application of keratin from natural resources: a review,” 3 Biotech, vol. 11, no. 5, p. 220, May 2021], Keratin extraction is via chemical, thermal, or enzymatic methods that target the disruption of strong13MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 disulfide bonds and intermolecular interactions [J. Zach, et al., Energy and Buildings, vol. 49, pp. 246-253, June 2012, N. Senthilkumar, et al., J Mater Cycles Waste Manag, vol. 25, no. 1, pp. 1-16, Jan. 2023], Chemical methods include acid / alkali hydrolysis, oxidation, reduction, and dissolution in ionic liquids. The use of chemical solvents in these approaches raises toxicity concerns [S. G. Giteru, et al., Comprehensive Reviews in Food Science and Food Safety, vol. 22, no. 1, pp. 643-687, 2023], Thermal methods, including microwave irradiation, superheated water hydrolysis, and steam explosion, disrupt disulfide and peptide bonds without hazardous chemicals, but result in lower yields [A. Shavandi, et al., “Keratin: dissolution, extraction and biomedical application,” Biomaterials Science, vol. 5, no. 9, pp.1699-1735, 2017], A less-toxic method, enzymatic hydrolysis, uses microbial enzymes that trigger sulfitolysis, proteolysis, and deamination to break down disulfide bridges and insoluble keratin proteins. Still, production time limits industrial scale-up [S. G. Giteru, et al., Comprehensive Reviews in Food Science and Food Safety, vol. 22, no. 1, pp. 643-687, 2023; C. R. Chilakamarry et al., 3 Biotech, vol. 11, no. 5, p. 220, May 2021; T. Kornillowicz-Kowalska et al., “Biodegradation of keratin waste: Theory and practical aspects,” Waste Management, vol. 31, no. 8, pp. 1689-1701, Aug. 2011], These keratin extraction processes may assist biodegradability as an organic fertilizer, improving end-of-life outcomes [G. D. Gillespie, et al., Sustainability, vol. 14, no. 1, p. 365, Dec. 2021; H. Akca, et al., “Waste Sheep Wool and Its Hydrolysate as a Nutritional Support for Sugar Beet,” Sugar Tech, vol.25, no. 6, pp. 1566-1577, Dec. 2023; F. N. Nelly Noah Metomo, et al., “Production of sheep wool keratin hydrolysate and evaluation of its effectiveness in promoting maize cultivation,” Journal of Environmental Management, vol. 366, p. 121648, Aug. 2024],

[0050] Existing Applications of Wool and Keratin-based Biomaterials:

[0051] Researchers have developed keratin films plasticized with glycerol and sodium dodecyl sulfonic acid to modulate their hydrophobicity and mechanical properties, with applications in regenerative medicine, coatings, packaging, and biodegradable plastics [B. Fernandez-d’ Arias, “Tough and Functional Cross-linked Bioplastics from Sheep Wool Keratin,” Sci Rep, vol. 9, no. 1, p. 14810, Oct. 2019], 3D printable biomaterials have been successfully formulated using wool-derived keratin, such as biobased inks containing keratin, alginate, salvia extracts, and cellulose nanofibers [L. Ugarte, B. Fernandez-d’ Arias, et al., “Revalorization of sheep-wool keratin for the preparation of fully biobased printable inks,” J Polym Environ, vol. 31, no. 10, pp. 4302-4313, Oct. 2023], Researchers have chemically modified wool with sodium silicate to make thermally stable microscale keratin powders for14MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 high-temperature extrusion, 3D printing, thermally resistant coatings, and insulation materials in automotive and construction sectors [A. N. M. A. Haque, et al., “Thermally stable microsized silica-modified wool powder from one-step alkaline treatment,” Powder Technology, vol. 404, p. 117517, May 2022],

[0052] Wool has been explored as a reinforcing component in composite materials, including bio-based matrices incorporating wool, sulfur, and canola oil [I. Bu Najmah et al., “Insulating Composites Made from Sulfur, Canola Oil, and Wool,” ChemSusChem, vol. 14, no. 11, pp.2352-2359, 2021], as well as biochar for enhanced flame resistance and mechanical performance [Oisik Das, et al., “Development of waste based biochar / wool hybrid biocomposites: Flammability characteristics and mechanical properties,” Journal of Cleaner Production, vol. 144, pp. 79-89, Feb. 2017], In cementitious matrices, wool fibers reduce thermal conductivity and improve insulation, but reduce compressive strength [V. Fiore, et al., “Effect of Sheep Wool Fibers on Thermal Insulation and Mechanical Properties of Cement-Based Composites,” Journal of Natural Fibers, vol. 17, no. 10, pp. 1532-1543, Oct.2020], The use of wool fibers as a structural reinforcement in rammed earth materials is an example of hybrid earthen construction systems from agricultural waste [M. C. M. Parlato, et al., “Natural fibers reinforcement for earthen building components: Mechanical performances of a low quality sheep wool (‘Valle del Belice’ sheep),” Construction and Building Materials, vol. 326, p. 126855, Apr. 2022], Other composite systems with acrylic-polyurethane resin and natural rubber latex also exhibit sufficient thermal insulation [T.-O. Denes et al., “Analysis of Sheep Wool-Based Composites for Building Insulation,” Polymers, vol. 14, no.10, p. 2109, May 2022], In addition, polypropylene (PP)-based wool composites containing up to 90% wool fiber have been developed via compression molding, with mechanical properties suitable for ceiling tiles and automotive components [V. Guna et al., “Engineering Sustainable Waste Wool Biocomposites with High Flame Resistance and Noise Insulation for Green Building and Automotive Applications,” Journal of Natural Fibers, vol. 18, no. 11, pp.1871-1881, Nov. 2021], Resinification of woven wool fabrics through heat pressing at elevated temperatures and pressures has demonstrated that wool descaling treatments facilitate resin formation [S. Akioka, et al., “Creation of High-impact-resistant Bioresin from Wool Fabric and its Reversible Resinification,” Fibers Polym, vol. 22, no. 12, pp. 3251— 3260, Dec. 2021], Researchers have introduced a rigid insulation panel fabricated from recycled wool and waste cardboard, which exhibited structural rigidity, competitive thermal conductivity, and acoustic and formaldehyde absorption [D. Bosia et al., “Sheep Wool for15MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 Sustainable Architecture,” Energy Procedia, vol. 78, pp. 315-320, Nov. 2015], Similarly, semi-rigid bio-insulation panels composed of alkali-treated wool and hemp fibers achieved high thermal and acoustic performance [R. Pennacchio et al., “FITNESs: Sheep-wool and Hemp Sustainable Insulation Panels,” Energy Procedia, vol. Ill, pp. 287-297, Mar. 2017], The addition of poultry feathers to wool and PP has also been explored in the production of composite panels with excellent noise, thermal, and flame-resistant properties [M. Ilangovan et al., “Hybrid biocomposites with high thermal and noise insulation from discarded wool, poultry feathers, and their blends,” Construction and Building Materials, vol. 345, p. 128324, Aug. 2022],

[0053] Citric Acid as an Environmentally Friendly Crosslinker:

[0054] Citric acid (CA), a naturally derived tricarboxylic acid, facilitates covalent intermolecular di-ester linkages between its carboxyl groups and the hydroxyl groups of various biopolymers, providing an affordable, environmentally friendly crosslinking agent in biopolymeric materials, hydrogels, membranes, and composites that enhance water resistance, mechanical stability, and biodegradability [D. O. S. Ramirez, et al., “Wool keratin film plasticized by citric acid for food packaging,” Food Packaging and Shelf Life, vol. 12, pp. 100-106, June 2017], Wool keratin plasticized with CA has produced transparent and extensible films for packaging with excellent biocidal activity, high elongation at break (-600%), and strong resistance to keratin leaching in water [D. O. S. Ramirez, et al., Food Packaging and Shelf Life, vol. 12, pp. 100-106, June 2017], CA has also been used to crosslink potato starch and chitosan for rougher, more water-resistant antimicrobial films with denser structures and stronger mechanics [H. Wu et al., “Effect of citric acid induced crosslinking on the structure and properties of potato starch / chitosan composite films,” Food Hydrocolloids, vol. 97, p. 105208, Dec. 2019], Keratin from chicken feathers was combined with glycerol and CA to produce thermoplastic films with improved water stability and mechanical strength [Nerendra Reddy, et al., “Biothermoplastics from hydrolyzed and citric acid Crosslinked chicken feathers,” ResearchGate, May 2025], Such studies demonstrate that CA can make safe, renewable, and scalable biomaterials from keratin waste streams.

[0055] Insulation in Reducing Building Environmental Impact:

[0056] Buildings account for 39% of global energy-related emissions, including both operational and embodied emissions [World Green Building Council, “Bringing embodied carbon upfront: Coordinated action for the building and construction sector to tackle embodied carbon,” Sept. 2019], Space and water heating typically rely on natural gas,16MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 generating -60% of the heating demand, and over 80% of operational CO2 emissions in buildings [“Heating,” IEA. https: / / www.iea.org / energy-system / buildings / heating]. While low-carbon and efficient energy heating, ventilating, and air-conditioning (HVAC) systems are rightfully positioned as a necessary mitigation strategy, building envelope design, especially thermal insulation, has been identified as a primary energy-reducing strategy [“AR6 Synthesis Report: Climate Change 2023 — IPCC ” https: / / www.ipcc.ch / report / sixth-assessment-report-cycle / ]. However, conventional insulation materials such as fiberglass, polystyrene, polyurethane foam, and glass and mineral wool rely on carbon-intensive petrochemicals with environmental and health hazards [L. Aditya et al., “A review on insulation materials for energy conservation in buildings,” Renewable and Sustainable Energy Reviews, vol. 73, pp. 1352-1365, June 2017; G. Yildiz, et al., “Performances Study of Natural and Conventional Building Insulation Materials,” International Journal on Advanced Science, Engineering and Information Technology, vol. 11, p. 1395, Aug. 2021; A. M. Papadopoulos, “State of the art in thermal insulation materials and aims for future developments,” Energy and Buildings, vol. 37, no. 1, pp. 77-86, Jan. 2005], Natural fiber insulation and rigid fiberboard, such as medium-density fiberboard (MDF) alternatives using urea-formaldehyde resin binders, are a primary source of indoor volatile organic compound (VOC) emissions in the form of outgassed formaldehyde, a carcinogen and respiratory irritant [T. Salthammer, et al., “Formaldehyde in the Indoor Environment,” Chem. Rev., vol. 110, no.4, pp. 2536-2572, Apr. 2010], Researchers have shown that environmentally friendly ureaformaldehyde resin alternatives, such as demethylated lignin nanoparticles, can improve the properties of MDF and reduce associated harmful emissions [A. Dorieh, et al., “Advancing Sustainable Building Materials: Reducing Formaldehyde Emissions in Medium Density Fiber Boards with Lignin Nanoparticles (Adv. Sustainable Syst. 9 / 2024),” Advanced Sustainable Systems, vol. 8, no. 9, p. 2470032, 2024], Further, the architecture, engineering, and construction industry (AEC) has shifted attention beyond operational energy efficiency to include the full life cycle emissions of materials [N. Pargana, et al., “Comparative environmental life cycle assessment of thermal insulation materials of buildings,” Energy and Buildings, vol. 82, pp. 466-481, Oct. 2014], Certifications like LEED, BREEAM, Zero Carbon, and CORE now consider embodied carbon [J. Grinham et al., “Zero-carbon balance: The case of HouseZero,” Building and Environment, vol. 207, p. 108511, Jan. 2022], Natural fibers like sheep wool have been shown to be less energy-intensive alternatives to conventional insulation [J. Zach, et al., Energy and Buildings, vol. 49, pp. 246-253, June17MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 2012; G. Yildiz et al., International Journal on Advanced Science, Engineering and Information Technology, vol. 11, p. 1395, Aug. 2021], A life cycle assessment (LCA) of Merino wool in New Zealand showed that wool requires only 50% of the energy and resources needed to produce polyester, and just 25% compared to nylon [G. R. Gowane, et al., “Climate Change Impact on Sheep Production: Growth, Milk, Wool, and Meat,” in Sheep Production Adapting to Climate Change, V. Sejian, R. Bhatta, J. Gaughan, P. K. Malik, S. M. K. Naqvi, andR. Lal, Eds., Singapore: Springer, 2017, pp. 31-69], Thus, developing high-performance insulation materials that leverage natural fibers, such as sheep wool, can be a sustainable solution for healthy, low-operational-energy, and low-embodied-carbon building materials.

[0057] Sheep Wool as a Building Material: Existing Uses and Limitations:

[0058] Sheep wool has a long history as an insulating material, exemplified by Mongolian yurts

[0048] , Today, wool insulation is produced as batts, rolls, loose-fill, and ropes for walls, roofs, and attics [K. W. Corscadden, et al., “Sheep’s wool insulation: A sustainable alternative use for a renewable resource?,” Resources, Conservation and Recycling, vol. 86, pp. 9-15, May 2014; M. Parlato et al., “Organized Framework of Main Possible Applications of Sheep Wool Fibers in Building Components,” Sustainability, vol. 12, p. 761, Jan. 2020; J. Grinham et al., Building and Environment, vol. 207, p. 108511, Jan. 2022], Wool insulation offers several performance benefits, exhibiting similar thermal conductivity to expanded polystyrene (EPS) foam and fiberglass [M. Parlato et al., “Organized Framework of Main Possible Applications of Sheep Wool Fibers in Building Components,” Sustainability, vol. 12, p. 761, Jan. 2020; G. Yildiz, et al., “Performances Study of Natural and Conventional Building Insulation Materials,” International Journal on Advanced Science, Engineering and Information Technology, vol. 11, p. 1395, Aug. 2021; S. Hetimy, et al., “Exploring the potential of sheep wool as an eco-friendly insulation material: A comprehensive review and analytical ranking,” Sustainable Materials and Technologies, vol. 39, p. e00812, Apr. 2024], Wool can absorb moisture up to 35% of its weight, preventing condensation as it naturally controls the indoor humidity [J. Zach, et al., Energy and Buildings, vol. 49, pp. 246-253, June 2012], It is fire retardant due to nitrogen content and self-extinguishes from a high ignition temperature [O. Denes, et al., “Utilization of Sheep Wool as a Building Material,” Procedia Manufacturing, vol. 32, pp. 236-241, 2019], Its acoustical insulation properties are suitable for sound absorption boards [S. Hetimy, et al., “Exploring the potential of sheep wool as an eco-friendly insulation material: A comprehensive review and analytical ranking,”18MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 Sustainable Materials and Technologies, vol. 39, p. e00812, Apr. 2024; O. Denes, et al., “Utilization of Sheep Wool as a Building Material,” Procedia Manufacturing, vol. 32, pp. 236-241, 2019; K. O. Ballagh, “Acoustical properties of wool,” Applied Acoustics, vol. 48, no. 2, pp. 101-120, June 1996; A. Koijenic, et al., “Sheep Wool as a Construction Material for Energy Efficiency Improvement,” Energies, vol. 8, no. 6, pp. 5765-5781, June 2015], There are also benefits associated with occupational health [J. Zach, et al., Energy and Buildings, vol. 49, pp. 246-253, June 2012], along with a natural ability to absorb pollutants and VOCs like formaldehyde [R. Del Rey, et al., “Characterization of Sheep Wool as a Sustainable Material for Acoustic Applications,” Materials, vol. 10, no. 11, Art. no. 11, Nov.2017; Romina del Rey et al., “Characterization of New Sustainable Acoustic Solutions in a Reduced Sized Transmission Chamber.” https: / / www.mdpi.eom / 2075-5309 / 9 / 3 / 60; A. Ghosh et al., “Keratinous Materials as Novel Absorbent Systems for Toxic Pollutants,” DSJ, vol. 64, no. 3, pp. 209-221, May 2014], Additionally, 50% of clean wool by weight is biogenic carbon, which is the carbon stored in the fibers during growth as part of the natural carbon cycle [Paul Swan, “Wool & the Carbon Cycle.” IWTO], Furthermore, both untreated and chemically modified sheep wool have exhibited biodegradability in composting conditions, adding onto its environmental benefits [S. Collie, et al., “Biodegradation behavior of wool and other textile fibers in aerobic composting conditions,” Int. J. Environ. Sci. Technol., vol.22, no. 4, pp. 2113-2125, Feb. 2025], Still, the broad adoption of wool in building construction remains limited as the efficacy of moisture, fire, and mechanical properties requires further commercial development [G. Tsovoodavaa, et al., “A review and systemization of the traditional Mongolian yurt (GER),” Pollack Periodica, vol. 13, no. 3, pp.19-30, Dec. 2018; E. Mansour, et al., “Absorption of Formaldehyde by Different Wool Types,” 2015],

[0059] Utilizing the keratin-rich gel described below, the inventors have created a biocomposite panel that provides weather durability and enhanced insulation properties using a nearly 100% wool product (i.e., no petrochemicals). This solution seeks to shift part of the construction market away from carbon-intensive cement and PVC siding. Wool fibers’ natural ability to trap air pockets through their kinks and bends will further enhance the insulating properties of the biocomposite panels. While loose-packed wool has been used as insulation for centuries, its scalable deployment across various building types remains limited.

[0060] Novel Wool Biocomposite Panel:19MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0061] This invention provides a stiff, structurally stable biocomposite panel fabricated from waste wool. The upcycling of low-value or discarded wool provides a plurality of environmental benefit including the elimination of petrochemical materials and VOC emitting urea-formaldehyde resins, reducing the demand for carbon-intensive, toxic materials while addressing the disposal problem of surplus wool at the pre-consumer stage. Furthermore, compared to interior retrofits — which often require invasive demolition, relocation of services, and occupant displacement — exterior retrofits can offer a higher return on investment and faster implementation timelines. The rigid wool biocomposite panel is intended to serve as a thermally insulating and structurally robust cladding component that can facilitate such retrofitting strategies while contributing to operational and embodied carbon reductions in the built environment. In this invention, the novel biocomposite panel's structural, thermal, and life cycle carbon potential is benchmarked against prevalent building industry materials, MDF and expanded polystyrene foam (EPS) [Medium Density Fiberboard (MDF) Market Size - Industry Report & Analysis.” https: / / www.mordorintelligence.com / industry-reports / medium-density-fiberboard-mdf-market; “Expanded Polystyrene Market - Size, Analysis & Share.” https: / / www.mordorintelligence.com / industry-reports / global-expanded-polystyrene-eps-market-industry],

[0062] Methodology:

[0063] Through early discovery, inventors have developed methods to extract keratin from wool fiber waste streams, producing a polymer for biocomposite applications. The process involves several key steps as shown in FIG. 1 and FIG. 2. The steps include reducing wool fibers to increase surface area, applying an alkaline treatment to break down keratin’s complex structure, and extracting the keratin into a concentrated gel, coined as keratin-rich gel.

[0064] Trimming: The first step in processing wool into a keratin polymer involves physically reducing the fiber length through trimming. In this process, wool fibers are cut into 5-10 mm strands using scissors. Cutting the fibers into smaller segments increases the wool’s surface area and facilitates the subsequent dissolution and breakdown of the wool, ensuring a more uniform and efficient conversion into the desired polymer.

[0065] Hydrolysis: The trimmed wool fibers are then submerged in a sodium hydroxide (0.1 N) solution. This process is commonly called hydrolysis in the textile industry, and it is used to descale and smoothen the fiber surface as well as to increase dye uptake. The alkaline bath20MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 is critical in breaking down the wool’s structural integrity by removing the outermost layer of the fiber, known as the cuticle. SEM images confirm the smoothening of the fiber surface, as shown in FIG. 3. The hydrolysis process breaks down the disulfide and peptide bonds within the keratin protein. Disulfide bonds, which are covalent links between sulfur atoms in cysteine residues, are responsible for stabilizing the keratin’s alpha-helical structure. The NaOH reacts with these bonds, reducing them and causing the keratin helices to unfold.Simultaneously, the peptide bonds that link amino acids in the protein chain are hydrolyzed, further degrading the wool fibers. This process effectively breaks down the wool into smaller, more manageable components, paving the way for the extraction of keratin in a polymer form.

[0066] Rinsing: The hydrolyzed wool fibers are then rinsed to neutral pH. This step is crucial for preventing the over-degradation of the wool fibers and ensuring that the resulting material is safe for further processing. The wool is rinsed until it reaches a neutral pH of 7, indicating that all alkaline residues have been effectively removed.

[0067] Blending: The rinsed wool fibers are then subjected to mechanical processes to break into a refined, aqueous suspension of microfibrils - tiny fragments of keratin that are the building blocks of the final polymer. The wool fibers are submerged in deionized water and blended for 5 minutes. This process physically shears the fibers, breaking them into smaller fragments and dispersing them in the water to create a milky, aqueous solution. The aqueous solution containing the microfibrils is separated from any larger residual fibers with a filter.

[0068] Centrifugation: The aqueous solution is centrifuged at 11,000 rpm for 30 minutes. The resulting pellet - a gel -like substance which is a highly concentrated solution of keratin-rich microfibrils that retains the original wool fibers' essential structural and mechanical properties. This keratin-rich gel is stored at low temperatures (around 4-6 degrees Celsius) to preserve its properties and prevent degradation.

[0069] The methods of the invention include, but not limited to, the preparation of keratin-rich gels, keratin biopolymer films, wool biocomposite fiberboards, and wool biocomposite fiberboards with raw wool composition, and are provided below.

[0070] Applications: The methods of the present invention are useful in various applications. The keratin-rich gel makes it suitable for various applications, particularly in developing biocomposites and other innovative materials as shown in FIG. 4 and FIG. 5 respectively. This keratin-rich gel can be further processed and combined with different materials to create21MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 new products that leverage the unique properties of keratin, such as strength, flexibility, and biodegradability.

[0071] Provided herein are methods of making a biopolymer film, fiberboard, composite fiberboard, coated fiberboard, coated composite fiberboard, coated felt, and coated wool textile from the keratin-rich gel.

[0072] Polymer Film: The keratin-rich gel can be made into biopolymer with the introduction of a cross-linker that creates hydrogen bonds with keratin molecules. Our work has succeeded in the fabrication of biopolymer films by mixing the keratin-rich gel with a 10% wt solution of citric acid. Hydrogen bonds are created through the interaction between the carboxyl groups on citric acid and the amine groups on the amino acids within the keratin protein chain. The mixture is cast in a mold and cured in the oven at 60 °C. Techniques to reduce the amount of bubbles in the cast include mixing mineral oil and slowing down the drying by putting a cover on the cast.

[0073] Fiberboard: The residual fibers - a byproduct of the claimed process - can be pressed into a fiber board. Using a hydraulic heat press increases the density and rigidity of the fiber board. However, these fiberboards will dissolve back into pulp once submerged in water.

[0074] Composite Fiberboard: The keratin-rich gel and residual fibers can be recombined to create a composite fiberboard. With the keratin-rich gel mixed into the fibers, the resulting composite fiberboard does not readily dissolve in water. In addition, early results of tensile testing for the composite fiberboard (COMP), the keratin-rich gel and PDMS control as presented in FIG. 6A and FIG. 6B showed increased stiffness in the composite fiberboard compared to the keratin-rich gel and PDMS control.

[0075] Coating: The keratin-rich gel can also be used as a coating over the fiberboard, composite fiberboard, or felt.

[0076] Challenges such as water absorption and shrinkage during curing can affect the material’s mechanical properties. However, addressing these through heat pressing (FIG. 7), freeze-drying, optimized water usage, and advanced waterproofing treatments will enhance efficiency and scalability. Further investigation into environmental externalities, such as water usage, is required to de-risk the process fully.

[0077] In the following description, for purposes of explanation, specific numbers, materials and configurations are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one having ordinary skill in the art that the invention may be practiced without these specific details. In some instances, well-known features may be22MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 omitted or simplified so as not to obscure the present invention. Furthermore, reference in the specification to phrases such as “one embodiment”, “an embodiment”, “an example embodiment” or “an exemplary embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the invention and could possibly be included in multiple different embodiments. The appearances of phrases such as “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.

[0078] In addition, it should be noted that whenever a value or range of values of a parameter are recited, it is intended that values and ranges intermediate to the recited values are also part of this invention.

[0079] In order that the disclosure may be more readily understood, certain terms are first defined. These definitions should be read in light of the remainder of the disclosure and as understood by a person of ordinary skill in the art. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art. Additional definitions are set forth throughout the detailed description.

[0080] I. DEFINITIONS

[0081] Applicant specifically incorporates the entire contents of all cited references in this disclosure. Further, when an amount, concentration, or other value or parameter is given as either a range or a list of upper values and lower values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or value and any lower range limit or value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the present disclosure be limited to the specific values recited when defining a range.

[0082] The indefinite articles “a” and “an”, as used herein should be understood to mean “at least one,” unless clearly indicated to the contrary.

[0083] The phrase “and / or”, when used between elements in a list, is intended to mean either (1) that only a single listed element is present, or (2) that more than one element of the list is present. For example, “A, B, and / or C” indicates that the selection may be A alone; B alone; C alone; A and B; A and C; B and C; or A, B, and C. The phrase “and / or” may be used interchangeably with “at least one of or “one or more of the elements in a list.23MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0084] Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range from the group consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50.

[0085] “Alpha-keratin” or “a-keratin” is an a-helical fibrous protein found in higher animals such as mammals, birds and reptiles. Alpha-keratin is the primary component of hairs, horns, nails and the epidermal layer of the skin. The secondary structure of natural alpha-keratin is composed predominantly of alpha-helices, which form coiled-coil dimers in strands along the fiber axis.

[0086] As used herein, “residual fiber” refers to the solid wool fiber fraction remaining after hydrolysis and mechanical homogenization, which is separated from the aqueous solution by filtration.

[0087] As used herein, “microfibrils” refers to the fine filaments nested inside macrofibrils within the cortical cells of wool fibers.

[0088] As used herein, “keratin-rich gel” refers to a gel-like material obtained via centrifugation of the aqueous solution produced via hydrolysis, mechanical homogenization, and removal of residual fibers by filtration.

[0089] As used herein, “hair” includes human hair and hair of other animals (e.g., mammals) including, but not limited to wool and fur.

[0090] II. MATERIALS

[0091] Scoured, loose sheep wool fibers were collected from American Woolen Company in Stafford Springs, Connecticut, USA. These fibers were deemed as pre-consumer waste from the textile manufacturing process. Sodium hydroxide pellets (97%, Oakwood Chemicals) were used for the alkaline treatment of the wool fibers, and hydrochloric acid (37%, Sigma-Aldrich) was used to neutralize afterward. Citric acid powder (99%, Sigma-Aldrich) was used as a crosslinking agent for the wool biocomposite material. Deionized water was used for solution preparation and rinsing steps. All chemicals were used as received without further purification.

[0092] III. METHODS OF THE INVENTION

[0093] A, Method for preparing a keratin-rich gel.

[0094] As described above, the present invention is based, at least in part, on the discovery of methods for preparing a keratin-rich gel.24MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0095] Accordingly, in one aspect, the present invention provides a method for preparing a keratin-rich gel comprising of steps a-g respectively.

[0096] Step (a):

[0097] The method begins with providing a keratin-rich wool fiber. Such keratin-rich wool fiber can include animal fragments, feather, hair, skin, fingernail, hoof, wool-based textile, or a combination thereof.

[0098] Hair suitable for use in the methods of the invention may be human hair or animal hair. In one embodiment, the hair is animal hair. In one embodiment, the animal hair is wool, for e.g., sheep wool, goat wool, alpaca wool, bison wool, or rabbit wool.

[0099] In one embodiment, the wool is sheep wool.

[0100] In one embodiment, the keratin-rich wool fiber comprises of alpha-keratin, betakeratin, or a combination thereof.

[0101] Step (b):

[0102] The keratin-rich wool fiber were cut into strands. In one embodiment, the strands is about 10 microns to about 100 microns in size. In another embodiment, the strands is about 0.5 cm to about 1 cm in size.

[0103] For example, the strands can be about 10 microns, about 20 microns, about 30 microns, about 40 microns, about 50 microns, about 60 microns, about 70 microns, about 80 microns, about 90 microns, or about 100 microns in size.

[0104] In another example, the strands can be about 0.5 cm, about 0.6 cm, about 0.7 cm, about 0.8 cm, about 0.9 cm, about 1.0 cm of size. Values intermediate to the above recited ranges and values are also contemplated to be part of the invention.

[0105] Step (c):

[0106] The trimmed wool fiber from step (b) were then treated with an alkaline solution at about 60 °C for about 24 hours to obtain a hydrolyzed wool fiber.

[0107] In one embodiment, the alkaline solution is an aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium sulfide, and ammonia, and combinations thereof.

[0108] In one embodiment, the concentration of the alkaline solution is about 0.04 N, about 0.06 N, about 0.08 N, about 0.1 N, about 0.12 N, about 0.14 N, about 0.16 N, or about 0.2 N. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention.MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0109] In one embodiment, the alkaline solution is an aqueous solution comprising about 0.1 N sodium hydroxide.

[0110] Step (d):[OHl] The hydrolyzed wool fiber from step (c) was rinsed with de-ionized or distilled water to a neutral pH to obtain a rinsed wool fiber.

[0112] In one embodiment, the neutral pH is from about 6.5 to about 7.5. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention.

[0113] Step (e):

[0114] The rinsed wool fiber from step (d) was immersed in de-ionized or distilled water. This was followed by mechanical blending and / or sonication for at least 5 minutes to obtain a milky aqueous solution.

[0115] Step (f):

[0116] The milky aqueous solution from step (e) was then separated to obtain a residual fiber and an aqueous solution containing microfibrils.

[0117] In one embodiment, separating the milky aqueous solution is achieved by filtration, sedimentation, electrostatic precipitation, addition of coagulants, addition of flocculants, or a combination thereof.

[0118] Step (g):

[0119] The aqueous solution containing microfibrils from step (f) was centrifuged for at least 30 minutes to obtain a keratin-rich gel.

[0120] In one embodiment, the keratin-rich gel is biocompatible and biodegradable. In one embodiment, the methods described herein are sustainable and scalable.

[0121] In some embodiments, the keratin-rich gel has tunable mechanical and thermal properties and holds promise for applications such as biopolymer film, fiberboard, composite fiberboard, coated fiberboard, coated composite fiberboard, coated felt, and coated wool textile.

[0122] B, Method of making a biopolymer film,

[0123] Step (1): In one embodiment, the invention relates to a method of making a biopolymer film, the method comprising providing the keratin-rich gel as described above.

[0124] Step (2): The keratin-rich gel is then mixed with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture.26MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0125] In some embodiments, the keratin-rich gel is mixed with a solution comprising about 0.1% wt, about 0.5% wt, about 1% wt, about 5% wt, about 10% wt, about 20% wt, about 30% wt, about 40% wt, about 50% wt, about 60% wt, about 70% wt, about 80% wt, about 90% wt, or about 100% wt of a chemical cross-linker. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention.

[0126] In some embodiments, the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0127] In some embodiments, an anti-foaming agent is optionally added to the mixture obtained from this step (2). In some embodiments, the anti-foaming agent is a mineral oil or a surfactant.

[0128] Step (3): The mixture from step (2) was then subjected / injected into a mold, followed by curing to obtain a biopolymer film. In some embodiments, casting, extruding, spraying, jetting, injecting, or a combination thereof can be used to subject the mixture in the mold.

[0129] C. Method of making a fiberboard.

[0130] Step (1): In one embodiment, the invention relates to a method of making a fiberboard, the method comprising providing the residual fiber as described above.

[0131] Step (2): The residual fiber was compressed to obtain a fiberboard. In some embodiments, the compressing is performed with a hydraulic press, hydraulic heat press, mechanical press, or a mechanical heat press.

[0132] In some embodiments, the fiberboard is low-density fiberboard (LDF), mediumdensity fiberboard (MDF), or high-density fiberboard (HDF).

[0133] D, Method of making a fiberboard.

[0134] Step (1): In one embodiment, the invention relates to a method of making a fiberboard, the method comprising providing the residual fiber as described above.

[0135] Step (2): Raw unprocessed wool fiber is provided in this step.

[0136] Step (3): The residual fiber and the raw unprocessed wool fiber were compressed to obtain a fiberboard. In some embodiments, the compressing is performed with a hydraulic press, hydraulic heat press, mechanical press, or a mechanical heat press.

[0137] In some embodiments, the fiberboard is low-density fiberboard (LDF), mediumdensity fiberboard (MDF), or high-density fiberboard (HDF).

[0138] E, Method of making a composite fiberboard.27MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0139] Step (1): In one embodiment, the invention relates to a method of making a composite fiberboard, the method comprising providing the keratin-rich gel as described above.

[0140] Step (2): The keratin-rich gel is then mixed with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture.

[0141] In some embodiments, the keratin-rich gel is mixed with a solution comprising about 0.1% wt, about 0.5% wt, about 1% wt, about 5% wt, about 10% wt, about 20% wt, about 30% wt, about 40% wt, about 50% wt, about 60% wt, about 70% wt, about 80% wt, about 90% wt, or about 100% wt of a chemical cross-linker. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention.

[0142] In some embodiments, the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0143] Step (3): The residual fiber prepared as described above is provided in this step.

[0144] Step (4): The residual fiber was then added to the mixture from step (2), followed by compressing to obtain a composite fiberboard. In some embodiments, the compressing is performed with a hydraulic press, hydraulic heat press, mechanical press, or a mechanical heat press. Such compressing techniques can result in temperatures ranging between 120-180 °C during the process.

[0145] In some embodiments, the ratio of the keratin-rich gel to the residual fiber is from about 0: 1 to about 1 :0. In some embodiments, the keratin-rich gel to the residual fiber can be present from about 0.1 : 100 by wt to about 100:0.1 by wt.

[0146] In some embodiments, increasing the ratio of the keratin-rich gel to the residual fiber decreases porosity and water absorption of the composite fiberboard.

[0147] In some embodiments, the ratio of the chemical cross-linker to the keratin-rich gel is from about 0: 1 to about 1:1. In some embodiments, for the biocomposite films, the chemical cross-linker to the keratin-rich gel can be present from about 0.1:100 by wt to about 1.5:5 by wt. In some embodiments, for the composite fiberboards, the chemical cross-linker to the keratin-rich gel can be present from about 0.1 : 100 by wt to about 7: 10 by wt.

[0148] In some embodiments, increasing the ratio of the chemical cross-linker to the keratin-rich gel improves mechanical strength of the composite fiberboard.28MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0149] In some embodiments, increasing the heat provided by hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press improves mechanical strength of the composite fiberboard.

[0150] F, Method of making a coated fiberboard.

[0151] Step (1): In one embodiment, the invention relates to a method of making a coated fiberboard, the method comprising providing the residual fiber as described above.

[0152] Step (2): The residual fiber was compressed to obtain a fiberboard. In some embodiments, the compressing is performed with a hydraulic press, hydraulic heat press, mechanical press, or a mechanical heat press.

[0153] Step (3): The keratin-rich gel prepared as described above is provided in this step.

[0154] Step (4): The fiberboard from step (2) is coated with the keratin-rich gel, followed by curing to obtain a coated fiberboard. In some embodiments, the coating is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

[0155] G. Method of making a coated composite fiberboard.

[0156] Step (1): In one embodiment, the invention relates to a method of making a coated composite fiberboard, the method comprising providing the keratin-rich gel as described above.

[0157] Step (2): The keratin-rich gel is then mixed with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture.

[0158] In some embodiments, the keratin-rich gel is mixed with a solution comprising about 0.1% wt, about 0.5% wt, about 1% wt, about 5% wt, about 10% wt, about 20% wt, about 30% wt, about 40% wt, about 50% wt, about 60% wt, about 70% wt, about 80% wt, about 90% wt, or about 100% wt of a chemical cross-linker. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention.

[0159] In some embodiments, the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0160] Step (3): The residual fiber prepared as described above is provided in this step.

[0161] Step (4): The residual fiber was then added to the mixture from step (2), followed by compressing to obtain a composite fiberboard. In some embodiments, the compressing is performed with a hydraulic press, hydraulic heat press, mechanical press, or a mechanical heat press.29MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0162] Step (5): The composite fiberboard from step (4) is coated with the keratin-rich gel, followed by curing to obtain a coated composite fiberboard. In some embodiments, the coating is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

[0163] H, Method of making a coated composite fiberboard.

[0164] Step (1): In one embodiment, the invention relates to a method of making a coated composite fiberboard, the method comprising providing the keratin-rich gel as described above.

[0165] Step (2): The keratin-rich gel is then mixed with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture.

[0166] In some embodiments, the keratin-rich gel is mixed with a solution comprising about 0.1% wt, about 0.5% wt, about 1% wt, about 5% wt, about 10% wt, about 20% wt, about 30% wt, about 40% wt, about 50% wt, about 60% wt, about 70% wt, about 80% wt, about 90% wt, or about 100% wt of a chemical cross-linker. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention.

[0167] In some embodiments, the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0168] Step (3): The residual fiber prepared as described above is provided in this step.

[0169] Step (4): The residual fiber was then added to the mixture from step (2), followed by compressing to obtain a composite fiberboard. In some embodiments, the compressing is performed with a hydraulic press, hydraulic heat press, mechanical press, or a mechanical heat press.

[0170] Step (5): The composite fiberboard from step (4) is coated with the mixture from step (2), followed by curing to obtain a coated composite fiberboard. In some embodiments, the coating is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

[0171] L_ Method of making a coated felt or a coated wool textile.

[0172] Step (1): In one embodiment, the invention relates to a method of making a coated felt or a coated wool textile, the method comprising providing the keratin-rich gel as described above.

[0173] Step (2): The keratin-rich gel is then mixed with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture.30MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0174] In some embodiments, the keratin-rich gel is mixed with a solution comprising about 0.1% wt, about 0.5% wt, about 1% wt, about 5% wt, about 10% wt, about 20% wt, about 30% wt, about 40% wt, about 50% wt, about 60% wt, about 70% wt, about 80% wt, about 90% wt, or about 100% wt of a chemical cross-linker. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention.

[0175] In some embodiments, the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0176] Step (3): A felt or a wool textile is provided in this step.

[0177] Step (4): The felt or the wool textile is coated with the keratin-rich gel, followed by curing to obtain a coated felt or a coated wool textile. In some embodiments, the coating is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

[0178] I_ Method of making a coated felt or a coated wool textile.

[0179] Step (1): In one embodiment, the invention relates to a method of making a coated felt or a coated wool textile, the method comprising providing the keratin-rich gel as described above.

[0180] Step (2): The keratin-rich gel is then mixed with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture.

[0181] In some embodiments, the keratin-rich gel is mixed with a solution comprising about 0.1% wt, about 0.5% wt, about 1% wt, about 5% wt, about 10% wt, about 20% wt, about 30% wt, about 40% wt, about 50% wt, about 60% wt, about 70% wt, about 80% wt, about 90% wt, or about 100% wt of a chemical cross-linker. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention.

[0182] In some embodiments, the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0183] Step (3): A felt or a wool textile is provided in this step.

[0184] Step (4): The felt or the wool textile is coated with the mixture from step (2), followed by curing to obtain a coated felt or a coated wool textile. In some embodiments, the coating is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

[0185] K, Method of making a coated felt or a coated wool textile.31MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0186] Step (1): In one embodiment, the invention relates to a method of making a coated felt or a coated wool textile, the method comprising providing the keratin-rich gel as described above.

[0187] Step (2): The keratin-rich gel is then mixed with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture.

[0188] In some embodiments, the keratin-rich gel is mixed with a solution comprising about 0.1% wt, about 0.5% wt, about 1% wt, about 5% wt, about 10% wt, about 20% wt, about 30% wt, about 40% wt, about 50% wt, about 60% wt, about 70% wt, about 80% wt, about 90% wt, or about 100% wt of a chemical cross-linker. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention.

[0189] In some embodiments, the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof. In some embodiments, the chemical cross-linker is citric acid.

[0190] Step (3): A felt or a wool textile is provided in this step.

[0191] Step (4): The felt or the wool textile was treated with an alkaline solution at about 60 °C for about 24 hours to obtain a hydrolyzed felt or a hydrolyzed wool textile.

[0192] In one embodiment, the alkaline solution in step (4) is an aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium sulfide, and ammonia, and combinations thereof.

[0193] In one embodiment, the concentration of the alkaline solution is about 0.04 N, about 0.06 N, about 0.08 N, about 0.1 N, about 0.12 N, about 0.14 N, about 0.16 N, or about 0.2 N. Ranges and values intermediate to the above recited ranges and values are also contemplated to be part of the invention. In one embodiment, the alkaline solution is an aqueous solution comprising about 0.1 N sodium hydroxide.

[0194] Step (5): The hydrolyzed felt or the hydrolyzed wool textile was rinsed with deionized or distilled water to a neutral pH of about 6.5 to about 7.5 to obtain a rinsed felt or a rinsed wool textile.

[0195] Step (6): The rinsed felt or the rinsed wool textile is coated with the mixture from step (2), followed by curing to obtain a coated felt or a coated wool textile. In some embodiments, the coating is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

[0196] IV. EXAMPLES32MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0197] The following examples are set forth as being representative of the present disclosure. These examples are not to be construed as limiting the scope of the present disclosure as these and other equivalent embodiments will be apparent in view of the present disclosure, figures and accompanying claims.

[0198] The Examples disclosed herein provide a method and formulation for extracting a keratin-rich gel via alkaline hydrolysis and plasticizing with citric acid to produce a continuous film. The keratin and citric acid gel worked as a binder to produce composite fiberboards with wool fibers treated and untreated with sodium hydroxide.

[0199] Further, the following Examples demonstrate the feasibility of producing a rigid, insulating biocomposite panel from waste wool using a process that leverages alkaline hydrolysis and citric acid crosslinking. The resulting fiberboards exhibit mechanical and thermal properties comparable to conventional medium-density fiberboards, while offering a lower environmental footprint, particularly when waste wool is used as the feedstock. The life cycle assessment highlights the importance of material sourcing, as panels from waste wool show significantly reduced global warming potential compared to panels derived from wool from dedicated farming.

[0200] The results from the Examples support the potential of wool waste valorization in the building sector as a circular, low-carbon alternative to petroleum-based insulation.

[0201] Example 1: Preparation of Keratin-rich Gel.

[0202] A batch of dry wool fibers (32 g) was processed with a paper shredder to trim the fibers and improve dispersibility. The trimmed fibers were soaked in 1600 mL of 0.1 M sodium hydroxide solution (NaOH) for 24 h in an oven at 60 °C (FIG. 2A). The alkaline treatment (pH = 13) removes the cuticle and partially extracts the keratin in the fibers. After the alkaline treatment, the processed wool fibers were neutralized by mixing 20 mL of 1 M hydrochloric acid (HC1) solution with 350 mL of deionized water and immersing the fibers in the resulting diluted acid solution (pH = 1). The neutralized fibers were then rinsed with deionized water to remove residual salts (primarily NaCl) from the neutralization reaction between NaOH and HC1. The fibers were then soaked in 600 mL of deionized water for mechanical processing with a blender. The blending process further breaks down the fibers, exposing the cortical cells and producing a turbid aqueous dispersion (FIG. 2B). The keratin solution was filtered using an ultrafine stainless steel mesh filter to separate the residual fibers from the aqueous protein solution (FIG. 2C). The aqueous solution was centrifuged at33MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 11000 rpm for 30 minutes at 20 °C. The supernatant was discarded to obtain the keratin-rich gel (FIG. 2D).

[0203] Example 2: Preparation of Keratin Biopolymer Films.

[0204] The keratin-rich gel was mixed with varying concentrations of citric acid solution, using a FlackTek Speedmixer at 3500 rpm for 1 minute. The mixture was cast in a 95 mm x 25 mm silicone mold. The cast was oven cured at 60 °C until dry, resulting in a flexible biopolymer film (FIG. 5 A). Films without the citric acid added were cast as controls to compare the flexibility and stability. Multiple manifestations of the keratin-based biopolymer with and without the processed residual fibers were explored earlier (FIGS. 5B-5E).

[0205] Example 3: Preparation of Wool Biocomposite Fiberboards.

[0206] The residual fibers described in Example 1 (FIG. 2C) were added to the keratin-rich gel and citric acid solution mixture. Once the fibers were mixed in, the mixture was placed in an oven for 3 h at 60 °C, before cold pressing in an acrylic mold (FIG. 8A) to remove the bulk of the water content (FIG. 8B). The pressed blocks were removed from the acrylic mold and dried at 60 °C overnight (FIG. 8C). Once dried, the blocks were heat-pressed on a bench-top manual heat press (Carver Mini CH 5420) at temperatures ranging between 120-180 °C in an aluminum mold (FIG. 8D), under a pressure of 5 MPa for 20 minutes (FIG. 8E).

[0207] Samples with various volumetric ratios of the keratin-rich gel and citric acid solution (10 wt%) were prepared (Table 1). The volumetric ratio represents the ratio of the cold-pressed wool fiber blocks (FIG. 8C) to the gel to the citric acid solution (10 wt%). All samples (specimens) A1-A6 contain 8 g of processed wool fiber (weighed in the unprocessed, dry state).

[0208] Table 1. Wool Biocomposite Fiberboard Samples.34MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0209] Example 4: Preparation of Wool Biocomposite Fiberboards with Raw Wool Composition.

[0210] Two modifications were made to prepare thicker wool biocomposite fiberboards to explore the potential scalability of the process for industrial applications. First, this process excludes the centrifuging step described in Example 1. Instead, the turbid aqueous phase was kept together with the processed fibers for further processing. Second, unprocessed wool was incorporated to increase the overall volume of the fiberboards. Mixing ratios for the thicker wool biocomposite fiberboards are included in Table 1 (samples B3, B4). Samples B3 and B4 contain 112 g of processed wool (weighed in the unprocessed, dry state) and 56 g of additional unprocessed wool to increase the thickness of the fiberboard. Like samples described in Example 3, citric acid content was calculated with the processed wool's assumed keratin content. The citric acid to assumed keratin content of samples B3 and B4 correspond to samples A3 and A4, respectively, as they exhibited the highest flexural modulus.

[0211] FIG. 9A shows examples of bending wool biocomposite fiberboard test samples Al-A6 as described in Table 1. FIG. 9B shows heat-pressed wool biocomposite fiberboard.

[0212] Shaping: 101.6 mm and 65 mm diameter circles and samples B3 and B4 were milled out on a Shapeoko 5 Pro computer numeric control (CNC) router (FIG. 9C). A 2-flute downcut endmill was used with a spindle speed of 24000 rpm, and a feed rate of 40 - 60. FIG. 10 shows the full scale prototype of wool biocomposite panel cladding system.

[0213] Example 5: Scanning Electron Microscopy (SEM),

[0214] Method: Unprocessed and processed wool fibers, keratin-rich gel, and a keratin-based biopolymer film were mounted onto 10 mm SEM stubs using double-sided carbon black tape. Excess fibers were removed by gently blowing compressed air over the surface. A 10 nm Pt / Pd conductive coating was sputtered onto the mounted samples using an EMS150TMEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 S sputter coater. The samples were imaged using scanning electron microscopy (Zeiss Gemini 360 FE-SEM) with a working voltage of 3.00 keV, primarily using the SE2 detector.

[0215] Results: Scanning Electron Microscopy (SEM) imaging shows the surface morphology of the wool fibers at each step of the process (FIG. 3). The image of the scoured, unprocessed fiber, as received from American Woolen Company, shows the outermost cuticle layer of the wool fiber (FIG. 3 A). After soaking in the alkaline bath for 24 h, it’s evident that the outermost cuticle layer is effectively removed as shown in FIG. 3B, while maintaining the internal structure of the fiber. Upon mechanical blending and filtering, exposed cortical cells were found in the keratin-rich gel (FIG. 3C). Finally, imaging of the keratin-based film (FIG. 3D) shows a relatively homogenous and conformal surface.Observed air cavities likely result from entrapped air as the water content in the cast evaporated while curing.

[0216] Conclusion: SEM imaging confirmed that the alkaline treatment stripped the outer cuticle layer of the wool fibers. Further mechanical blending exposed the inner cells of the fiber. The keratin-based film resulted in a relatively homogenous surface morphology.

[0217] Example 6: Fourier Transform Infrared Spectroscopy (FTIR),

[0218] Method: IR spectra were recorded with a Nicolet i S50 FTIR Spectrometer (Thermo Fisher Scientific, Waltham, MA, USA) by an attenuated total reflection (ATR) technique in the range of 4000 to 650 cm’1with 32 scans and 4 cm’1band resolution. OMNIC software was used to perform baseline correction and advanced ATR correction. IR spectra were zeroed at 1800 cm’1and normalized at 3283 cm’1to compare peak intensities in the 1700 cm’1to 1650 cm’1region, where prior research had analyzed keratin films plasticized with citric acid [D. O. S. Ramirez, et al., “Wool keratin film plasticized by citric acid for food packaging,” Food Packaging and Shelf Life , vol. 12, pp. 100-106, June 2017], Peak intensities were calculated by comparing the peak heights at 1647 cm’1to 1716 cm’1and 1710 cm’1for the films and fiber composites, respectively. The keratin biopolymer films prepared following the steps in Example 2 were rinsed with DI water to wash off any excess citric acid.

[0219] Results: The FTIR Analysis of keratin biopolymer films is provided as follows. The interactions between the keratin protein and Citric Acid (CA) were investigated by FTIR spectroscopy of a CA control, keratin biopolymer film with 0%, 10%, 20%, and 30% CA, and biocomposite A4 samples heated from 120 °C to 180 °C (FIGs. 11 A-l IB and FIGS. 12A-12B). Across all samples, peaks in the amide I band at ~ 1650 cm’1were attributed to the36MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 stretching vibrations of C=O bonds. Peaks in the amide II band at ~ 1540 cm'1were attributed to the combination of N-H bending and C-N stretching vibrations. The two peaks at 1743 cm'1and 1697 cm'1evident in the citric acid spectra were attributed to C=O stretching modes [D. O. S. Ramirez, et al., Food Packaging and Shelf Life, vol. 12, pp. 100-106, June 2017],

[0220] Results show one additional peak at ~ 1710 cm'1in the keratin-CA films and fiber composite compared to the keratin-only film and fiberboard, due to the presence of citric acid. This implies that citric acid has reacted with amino or hydroxyl groups on the keratin chains, resulting in plasticization through esterification. Further peak intensification is observed with increased CA content from 10-30% and with increased heat from 120-180 °C for the film and composite samples, respectively.

[0221] Discussion: Material Characterization: This study demonstrates the technical feasibility of creating rigid wool biocomposite panels using waste wool and the extracted keratin-rich gel mixed with citric acid. FTIR spectra analysis indicated esterification of the keratin - CA interaction. Film samples indicated increased peak intensity with increased CA. While composite samples indicated increased peak intensity with increased heat press temperature. These trends correlate directly with improved mechanical strength trends for composite samples A and B. Increasing both CA concentration and heat press temperature led to higher flexural modulus values, suggesting effective crosslinking and improved stiffness. These results point to the potential role of CA as both a crosslinker and performance enhancer for biopolymer-based composites derived from wool fibers. The ability to produce structurally stable panels from low-value waste wool streams supports the viability of this material system for applications requiring both strength and dimensional stability.

[0222] FTIR spectroscopy showed the emergence of new peaks at ~ 1710 cm'1with the addition of CA, and increased peak intensity with higher CA content and higher heat press temperatures. While these results confirm the mechanical test results, further analysis is necessary to gain a deeper understanding of the chemical reaction between the keratin protein and citric acid.

[0223] Conclusion: FTIR spectroscopy showed new peaks at ~ 1710 cm'1with the addition of citric acid, indicating plasticization through esterification, with higher peak intensities for samples with higher CA content and higher heat press temperatures.

[0224] Infrared spectra were zeroed at 1800 cm'1and normalized at 3283 cm'1to compare peak intensities in the 1700 cm'1to 1650 cm'1region based on prior spectra analysis of keratin films crosslinked with citric acid (FIGs. 11 A-l IB) show representative samples37MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 closest to average spectra) [D. O. S. Ramirez, et al., Food Packaging and Shelf Life, vol. 12, pp. 100-106, June 2017], Average peak intensities were calculated by comparing the peak heights at 1647 cm’1to 1716 cm’1and 1647 cm’1to 1710 cm’1for the films and fiber composites, respectively. The keratin biopolymer films prepared following the steps in Example 2 were rinsed with DI water to wash off any excess citric acid.

[0225] Example 7: Mechanical Properties.

[0226] Method: 3 -point bending tests (FIG. 13) were performed on an Instron 5566 universal testing machine (Instron Corp., Norwood, MA, USA) (FIG. 13A), following methods based on ASTM D790. The crosshead speed was 5 mm / min. Thin fiberboard specimens (nominal dimensions: 12.7 mm x 95 mm x ~2.9 mm) were tested with a support span of 46.4 mm. In comparison, thick fiberboard specimens (nominal dimensions: 12.7 mm x 165.1 mm x -6.35 mm) were tested with a span of 101.6 mm, following the standard 16:1 span-to-thickness ratio. Tests were concluded upon failure. Among samples A1-A6, for specimens that exhibited the highest flexural moduli, multiple samples were tested to verify the results (n = 5). 2.9 mm-thick and 6.35 mm-thick medium-density fiberboard (MDF) were used as controls for samples A1-A6 (FIG. 13B) and B3-B4 (FIG. 13C), respectively. The flexural stress Of was calculated following the equation for a rectangular cross section:

[0230] The flexural modulus Ef was calculated from the initial linear portion of the loaddeflection curve according to:

[0232] where F is the force at a given point (N), L is the support span (mm), b is the specimen width (mm), d is the specimen thickness (mm), D is the center-point displacement (mm), and m is the slope of the linear region in the load-deflection curve (N / mm).

[0233] Results: Flexural moduli of best performing thin wool fiberboard samples (A1-A6) and thick wool fiberboard samples (B3-B4) are disclosed herein. Three trends in flexural behavior across the composite formulations and heat-pressing temperatures are observed. Specimens pressed at higher heat-press temperatures exhibited higher flexural modulus values. Similarly, samples with higher citric acid concentrations (i.e., A3 and A4) showed higher flexural modulus. In contrast, increasing the proportion of keratin-rich gel alone did not lead to38MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 substantial increases in stiffness. However, formulations with higher gel content (i.e., A5 and A6 samples) outperformed those with lower gel concentration with the same citric acid content (A2 samples). Overall, the highest moduli were observed in samples with the greatest citric acid content and higher heat-press temperatures. For the thin wool fiberboard samples A4, pressed at 150 °C, exhibited a flexural modulus of 1676 + / - 58 MPa (n = 5), similar to that of MDF of similar thickness (3.175 mm), with a modulus of 1679 + / - 98 MPa (n = 3), the lower range reported for MDF (FIG. 14). For the thick wool fiberboard samples, the average flexural modulus for sample B4 was 1139 + / - 91 MPa. 6.35 mm thick MDF exhibited a flexural modulus of 3464 + / - 86 MPa, the upper range reported for MDF (FIG. 14).

[0234] Conclusion: Mechanical testing demonstrated similar flexural modulus between the wool biocomposite samples (1676 + / - 158 MPa, n=5) and medium-density fiberboards (1679 + / - 98 MPa, n=3). The addition of unprocessed wool increases sample volume and reduces the required processed fiber, resulting in a lower flexural modulus (1139 + / - 91 MPa, n=3).

[0235] Example 8: Thermal Conductivity.

[0236] Method: Thermal conductivity was measured using a guarded hot plate apparatus following ASTM C1044-16 (FIG. 15A). The apparatus consisted of a 60 mm diameter central heater in contact with one face of the specimen, surrounded by a 140 mm diameter guard heater to minimize lateral heat losses and promote one-dimensional heat transfer. The circular specimens were either 65 mm or 101.6 mm in diameter, ensuring that the specimen was larger than the contact area of the central heater. A cold plate was positioned against the opposite face of the specimen to establish a steady-state temperature gradient. Thermocouples were placed on both the central heater and guard heater to verify thermal equilibrium, and on the cold plate side of the specimen to monitor the temperature gradient (FIG. 15B). Two thermocouples were placed at each position to confirm the surface temperature's uniformity, and each pair's averages were used for calculations. Once steady-state conditions were achieved, thermal conductivity (k) was calculated using Fourier’s law:

[0238] where Q is the applied heat input (W), L is the specimen thickness (m), A is the cross-sectional area (m2), and A / i s the temperature difference between the heater and cold plate surfaces (K).

[0239] Results: Thermal conductivity measurements showed values of 0.106 + / - .004 W nr’ K-1for MDF and 0.130 + / - 0.02 W m ' K1for sample B4 (FIG. 16). The higher conductivity of the wool panel compared to loose wool (0.035 - 0.04 W nr’ K’1) [G. Yildiz,39MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 B. Durakovic, et al., International Journal on Advanced Science, Engineering and Information Technology, vol. 11, p. 1395, Aug. 2021] is expected due to the compression of the fibers during panel fabrication, which reduces air voids and increases the solid fraction, thereby decreasing its insulating performance relative to uncompressed wool.

[0240] Discussion: Thermal conductivity measurements confirm that the wool panels maintain reasonable insulating performance (0.12 - 0.13 W nr’ K-1), comparable to conventional wood-based panels such as MDF. The measured thermal conductivity of the compressed wool panels was higher than that of loose wool, which is consistent with the densification of fibers and reduction of insulating air pockets during panel fabrication. This presents a trade-off between structural rigidity and thermal performance. Thermal conductivity is a critical metric for the wool biocomposite panel as an insulative cladding material. Passive House Institute US requires an minimum effective R-value of 40 ft^TF h BTU'1(RSI = 7.04 m2K W-1) for exterior walls [“Phius CORE Prescriptive Standard Specifications, Phius Phius CORE Prescriptive Passive Standard Specifications.” https: / / www.phius.org / phius-core-prescriptive-standard-specifications]. Future design explorations could investigate hybrid systems, such as using the rigid panel as a structural shell combined with loose or minimally processed wool as internal insulation, potentially balancing mechanical strength with improved thermal resistance to reach a higher R-value for building applications.

[0241] Conclusion: Thermal conductivity testing demonstrated 0.120 + / - 0.009 W m ' K ’, similar to medium density fiberboards (0.105 + / - 0.003 W m1'!< '), but higher than that of expanded polystyrene foam (0.03 W nr’ K’1).

[0242] Example 9: Life Cycle Assessment (LCA),

[0243] Methods: Standards, methods, and system boundary: Life cycle assessment for the thick wool biocomposite fiberboard was conducted using SimaPro Craft (version 10.1.0.4) with the Ecoinvent v3 database following ISO 14040 / 44 LCA standards. Impact assessment was performed using the TRACI 2.1 V1.09 / US 2008 method for global warming potential (GWP). Following ISO 21930:2007 [“ISO 21930:2017,” ISO. https: / / www.iso.org / standard / 61694.html], biogenic carbon is reported in a separate line to account for the biomass carbon sequestered beyond system boundaries. However, this study excludes the carbon that is released back to the atmosphere at the end of life of the product; the corresponding amount published in the EPD for MDF [Composite Panel Association,40MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 “North American Medium Density Fiberboard (MDF) Environmental Product Declaration.” UL Environment] was removed accordingly for comparison.

[0244] The functional unit used for this study was defined as 1 m2with a thickness that provides a thermal resistance of RSI = m2K W-1(R-value 5.68 ft2hr °F BTU-1). For each material, the required thickness to achieve this thermal resistance was calculated based on measured or published thermal conductivity values. The required thickness is 12 cm for the wool panels, 10 cm for MDF, and 4 cm for EPS foam.

[0245] The system boundary was cradle-to-gate (Al -A3), including raw material extraction, processing, and manufacturing. Two distinct scenarios were analyzed: raw wool and waste wool collected from textile mills. The raw wool scenario includes the carbon footprint of sheep farming for wool. In contrast, the waste wool scenario assumes no emissions from raw material extraction, as it is a waste product.

[0246] Life Cycle Inventory Data: Primary inventory data for the wool panel production were developed based on laboratory-scale processing, scaled to approximate industrial conditions. The formulation and measured thermal conductivity of sample B3 were used for this assessment. It was assumed that multiple panels were manufactured at once to simulate industrial processing. The lab-scale liquor-to-fiber ratio of 1:50 (g:mL) (32 g of wool to 1600 mL of 0.1 M NaOH solution) was adjusted to 1:10 (g:mL) for the industrial-scale model to reflect typical process efficiencies with zero material loss. The total NaOH used per unit wool mass was kept constant, assuming equivalent chemical action under reduced bath volume with proper industrial mixing and temperature control. For subsequent neutralization and rinsing processes, a 10:1 liquor-to-fiber ratio was assumed.

[0247] The inventory data for material and energy inputs were sourced from the Ecoinvent v3 database, which contains LCI data from various sectors such as energy production, transport, building materials, and production of chemicals. Wherever possible, datasets representing North America were selected. Global or “Rest of the World” (RoW) datasets were used for processes where North American datasets were not available. While transportation of supplementary processing materials such as chemicals and electricity was included using the Ecoinvent database, transportation of the waste wool from collection sites to manufacturing facilities was assumed based on industry standard scenarios, as a specific collection for the waste wool and manufacturing facilities had not been established.

[0248] Benchmarking with commercial products: To benchmark the wool panels alongside conventional building materials, GWP values for the wool panel were compared with those of41MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 medium-density fiberboard (MDF) [Composite Panel Association, “North American Medium Density Fiberboard (MDF) Environmental Product Declaration.” UL Environment] and expanded polystyrene (EPS) foam [EPS Industry Alliance, “EPS Insulation Environmental Product Declaration.”], obtained directly from published Environmental Product Declarations (EPDs). All data included life cycle stages Al through A3. GWP values were compared with and without biogenic carbon accounting to evaluate the impact of biogenic carbon sequestration. To reflect the material thickness required to reach an RSI of 1 m2K W-1, the GWP values for the MDF functional unit (m3) were scaled by a factor of 0.1, equating to a 1 m2panel with a 10 cm depth.

[0249] Results: FIG. 17 shows the Global warming potential (GWP) for (a) EPS Foam, Biogenic Carbon (BC) excluded; (b) EPS Foam, BC included; (c) MDF, BC excluded; (d) MDF, BC included; (e) Wool panel, raw wool, BC excluded; (f) Wool panel, raw wool, BC included; (g) Wool panel, waste wool, BC excluded; and (f) Wool panel, waste wool, BC included. Life cycle assessment (LCA) results revealed a significant difference in global warming potential (GWP) between raw and waste wool scenarios. When normalized by mass, the raw wool scenario showed 40.13 kg CCh-eq- kg1without biogenic carbon (BC) included and 38.30 kg CCh-eq- kg-1with BC included. In comparison, the waste wool scenario showed a significantly lower footprint of 0.64 kg CCh-eq- kg-1without BC and -1.19 kg CCh-eq- kg-1with BC. MDF showed 0.97 kg CCh-eq- kg-1without BC and -0.68 kg CCh-eq- kg-1with BC, and EPS showed 4.38 kg CCh-eq- kg-1with or without BC since no carbon sequestration occurs (FIG. 17A).

[0250] For a panel thickness sufficient to achieve thermal resistance RSI = 1 m2K W-1(R-value 5.68 ft2hr °F BTU-1), the raw wool scenario (which includes the upstream emissions from sheep farming allocated to wool) yielded a GWP of 4741.08 kg CCh-eq without accounting for BC, and 4524.31 kg CCh-eq with BC included. In contrast, the waste wool scenario - excluding sheep farming under the assumption that wool is treated as a byproduct or waste - had a GWP of 75.70 kg CCh-eq without BC and -141.08 kg CCh-eq with BC. For comparison, MDF showed a GWP of 75.92 kg CCh-eq without BC and -53.37 kg CCh-eq with BC, while EPS foam had a GWP of 2.53 kg CCh-eq with or without BC, as it contains no biogenic carbon. (FIG. 17B). Notably, the high impact of the raw wool scenario is primarily driven by the dataset used for sheep farming, in which most of the upstream emissions from livestock production, such as enteric methane and feed-related emissions, are allocated in part to wool as a co-product.42MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0251] Discussion: The LCA results highlight the critical importance of system boundary and allocation choices when assessing the environmental impact of wool-based materials. When upstream emissions from sheep farming are attributed to wool, the global warming potential is significantly higher than that of conventional materials such as MDF and EPS foam. However, when wool is assumed to be a waste product, the GWP of the wool biocomposite panel falls well below that of both MDF and EPS when normalized by weight. These findings underscore the potential of wool waste valorization to serve as a low-carbon alternative in the building sector, while indicating that sourcing wool through dedicated sheep farming would substantially increase the panel’s environmental footprint.

[0252] Conclusion: Life cycle assessment calculations show upcycled waste wool panels have a lower global warming potential (0.64 kg CCh-eq kg1without biogenic carbon and -1.19 kg CCE-eq kg'1), compared to medium density fiberboard (0.97 kg CCh-eq kg1without biogenic carbon and -0.68 kg C Ch-eq- kg-1) and expanded polystyrene foam (4.38 kg CO2-eq kg1).

[0253] Life cycle assessment calculations show panels from wool obtained through dedicated sheep farming showed significantly higher global warming potential (40.13 kg CCE-eq kg'1without biogenic carbon and 38.30 kg CCE-eq kg'1).

[0254] Example 10: Water Absorption Test for Biocomposite Samples.

[0255] Method: Biocomposite samples are first dried in an oven for 24 hours, weighed, and then dried for an additional hour to ensure the base weight is within a 0.1% difference.Samples were then submerged and weighed after (a) 2 hours and (b) 24 hours. FIG. 18 shows the water absorption of MDF and Al, A4, B4, A7, A8, and A10 biocomposite samples after 2 hours and 24 hours. Control samples were MDF 3.175 mm thick, low range, and MDF 6.35mm thick, high range. Sample ratios are as follows: Al = 4:0:0 (no keratin gel or citric acid); A4 = 4:4:4; B4 = with raw fiber; 112 g of processed + 56 g of unprocessed + 15.5 g of citric acid; A7 = 4:8:8; A8 = 4:16:16; A10 = 4:4:16.

[0256] Results: Data in FIG. 18 indicate that the A7 sample’s higher keratin and citric acid content results in a more waterproof and dimensionally stable sample.

[0257] Example 11 : Fire Retardancy.

[0258] Wool is inherently flame-resistant due to its high nitrogen and water content, high ignition temperature (around 600 °C), and ability to char and release inert gases instead of melting. This makes it difficult to ignite, and it will often self-extinguish once the heat source is removed, without melting, dripping, or sticking to skin.43MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0259] FIG. 19 shows preliminary fire tests (left) cleaned wool, (center) wool fiber composite, and (right) medium-density fiberboard. Preliminary testing showed that the biocomposite retains these flame- resistant properties.

[0260] Example 12: Effect of Citric Acid and Heat on Composite Fiberboard.

[0261] FIG. 20 shows mechanical tests of MDF and wool biocomposite fiberboard specimens A1-A6 as described in Table 1 at 120 °C, 150 °C, and 180 °C. FIG. 20A is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimens Al-A6 at 120 °C. FIG. 20B is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimens A1-A6 at 150 °C. FIG. 20C is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimens A1-A6 at 180 °C.

[0262] FIG. 21 shows mechanical tests of MDF and wool biocomposite fiberboard specimens A1-A3 as described in Table 1 at 120 °C, 150 °C, and 180 °C. FIG. 21A is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen Al at 120 °C, 150 °C, and 180 °C. FIG. 21B is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A2 at 120 °C, 150 °C, and 180 °C. FIG.21C is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A3 at 120 °C, 150 °C, and 180 °C.

[0263] FIG. 22 shows mechanical tests of MDF and wool biocomposite fiberboard specimens A4-A6 as described in Table 1 at 120 °C, 150 °C, and 180 °C. FIG. 22A is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A4 at 120 °C, 150 °C, and 180 °C. FIG. 22B is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A5 at 120 °C, 150 °C, and 180 °C. FIG.22C is a stress-strain graph of MDF 3.175 mm thick, low range, and wool biocomposite fiberboard specimen A6 at 120 °C, 150 °C, and 180 °C.

[0264] FIG. 23 is a graph showing flexural moduli of (a) MDF 3.175 mm thick, low range (n=3); (b) wool biocomposite fiberboard specimen Al at 120 °C; (c) wool biocomposite fiberboard specimen Al at 150 °C; (d) wool biocomposite fiberboard specimen Al at 180 °C; (e) wool biocomposite fiberboard specimen A2 at 120 °C; (f) wool biocomposite fiberboard specimen A2 at 150 °C; (g) wool biocomposite fiberboard specimen A2 at 180 °C; (h) wool biocomposite fiberboard specimen A3 at 120 °C; (i) wool biocomposite fiberboard specimen A3 at 150 °C; (j) wool biocomposite fiberboard specimen A3 at 180 °C; (k) wool biocomposite fiberboard specimen A4 at 120 °C; (1) wool biocomposite fiberboard specimen44MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 A4 at 150 °C; (m) wool biocomposite fiberboard specimen A4 at 180 °C; (n) wool biocomposite fiberboard specimen 5 at 120 °C; (o) wool biocomposite fiberboard specimen A5 at 150 °C; (p) wool biocomposite fiberboard specimen A5 at 180 °C; (q) wool biocomposite fiberboard specimen A6 at 120 °C; (r) wool biocomposite fiberboard specimen A6 at 150 °C; and (s) wool biocomposite fiberboard specimen A6 at 180 °C.

[0265] In certain aspects of the disclosure, the ratio of the chemical cross-linker to the keratin-rich gel used in the method of making a composite fiberboard is from about 0: 1 to about 1 : 1

[0266] In certain aspects of the disclosure, increasing the ratio of the chemical cross-linker to the keratin-rich gel in the method of making a composite fiberboard improves mechanical strength of the composite fiberboard.

[0267] In certain aspects of the disclosure, the chemical cross-linker used in the method of making a composite fiberboard is preferably citric acid.

[0268] In certain aspects of the disclosure, in the method of making a composite fiberboard, hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press can be used in the compressing step. Such compressing techniques can result in temperatures ranging between 20-300 °C during the process.

[0269] In certain aspects of the disclosure, in the method of making a composite fiberboard, increasing the heat provided by hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press improves mechanical strength of the composite fiberboard.

[0270] Example 13: Composite Panel.

[0271] In some aspects of the disclosure, a composite wool panel featuring a bi-layer design can be prepared. Such wool panel systems are retrofittable and provides enhanced insulation and weatherization. FIG. 24 is a conceptual diagram of a retrofittable upcycle wool panel system. FIG. 25 is a prototype assembly of the bi-layer design. FIG. 25A is a picture of the exterior and interior layers of the composite panel. FIG. 25B is a picture of the assembled composite panel showing the interior layer side. FIG. 25C is a picture of the assembled composite panel showing the exterior layer side. The composite panel is assembled from (1) an exterior stiff, cross linked and heat pressed composite panel (intended for durability and water proofing) and (2) an interior less-stiff, non-cross linked or cross linked and non-heat pressed (just mechanically pressed) composite panel (intended for insulation) without heat and cross linking.45MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934

[0272] While the above Examples focused on pre-consumer sheep wool and the unique waste problem faced by the wool industry, there is also an opportunity to extend this approach to post-consumer textile waste. This could yield, a more -uniform fiber, greater performance, and economic returns, while broadening the scope of waste valorization and further reducing landfill burdens.

[0273] In addition to the demonstrated mechanical and thermal performance, the panel fabrication process presents applicability to existing industrial processes. The modified processing steps for the thicker panels, including the omission of centrifugation and integration of unprocessed wool, simplify manufacturing and point toward potential scalability. These adaptations suggest compatibility with existing equipment in textile mills (i.e., large vats, carding machines) or composite panel manufacturing facilities (i.e., drying kilns, heat presses).MEl\59581655.vl

Claims

Atorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 CLAIMSWhat is claimed is:

1. A method for preparing a keratin-rich gel comprising:(a) providing a keratin-rich wool fiber;(b) trimming the keratin-rich wool fiber into strands to obtain a trimmed wool fiber;(c) treating the trimmed wool fiber with an alkaline solution at about 60 °C for about 24 hours to obtain a hydrolyzed wool fiber;(d) rinsing the hydrolyzed wool fiber with deionized or distilled water to a neutral pH of about 6.5 to about 7.5 and obtain a rinsed wool fiber;(e) immersing the rinsed wool fiber in deionized or distilled water, followed by mechanical blending and / or sonication for at least 5 minutes to obtain a milky aqueous solution;(f) separating the milky aqueous solution to obtain a residual fiber and an aqueous solution containing microfibrils; and(g) centrifuging the aqueous solution containing microfibrils for at least 30 minutes to obtain a keratin-rich gel.

2. The method of claim 1, wherein the keratin-rich wool fiber is selected from hair, feather, wool-based textile, or a combination thereof.

3. The method of claim 2, wherein the hair is animal hair.

4. The method of claim 3, wherein the animal hair is wool.

5. The method of claim 4, wherein the wool is selected from sheep wool, goat wool, alpaca wool, bison wool and rabbit wool.

6. The method of claim 5, wherein the wool is sheep wool.

7. The method of any one of claims 1-6, wherein the keratin-rich wool fiber comprises of alpha-keratin, beta-keratin, or a combination thereof.47MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 8. The method of any one of claims 1-7, wherein the strands in step (b) is about 10 microns to about 100 microns in size.

9. The method of any one of claims 1-7, wherein the strands in step (b) is about 0.5 cm to about 1 cm in size.

10. The method of any one of claims 1-9, wherein the alkaline solution in step (c) is an aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium sulfide, and ammonia, and combinations thereof.

11. The method of any one of claims 1-10, wherein the concentration of the alkaline solution in step (c) is about 0.04 N, about 0.06 N, about 0.08 N, about 0.1 N, about 0.12 N, about 0.14 N, about 0.16 N, or about 0.2 N.

12. The method of claim 1, wherein the alkaline solution in step (c) is an aqueous solution comprising about 0.1 N sodium hydroxide.

13. The method of any one of claims 1-12, wherein separating the milky aqueous solution in step (f) is achieved by filtration, sedimentation, electrostatic precipitation, addition of coagulants, addition of flocculants, or a combination thereof.

14. The method of any one of claims 1-13, wherein the keratin-rich gel is biocompatible.

15. The method of any one of claims 1-13, wherein the keratin-rich gel is biodegradable.

16. A method of making a biopolymer film, the method comprising:(1) providing the keratin-rich gel prepared according to the method of any one of claims 1-15;(2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture; and(3) subjecting the mixture in a mold, followed by curing to obtain a biopolymer film.

17. The method of claim 16, wherein an anti -foaming agent is optionally added to the mixture obtained from step (2).48MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 18. The method of claim 17, wherein the anti-foaming agent is a mineral oil or a surfactant.

19. The method of claim 16, wherein subjecting the mixture in a mold in step (3) is performed by casting, extruding, sprayingjetting, injecting, or a combination thereof.

20. The method of claim 16, wherein the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof.

21. A method of making a fiberboard, the method comprising:(1) providing the residual fiber prepared according to the method of any one of claims 1-15; and(2) compressing the residual fiber to obtain a fiberboard.

22. The method of claim 21, wherein the compressing in step (2) is performed with a hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press.

23. The method of claim 21, wherein the fiberboard is low-density fiberboard (LDF), medium-density fiberboard (MDF), or high-density fiberboard (HDF).

24. A method of making a fiberboard, the method comprising:(1) providing the residual fiber prepared according to the method of any one of claims 1-15;(2) providing raw unprocessed wool fiber; and(3) combining via mechanical homogenization and compressing the residual fiber and the raw unprocessed wool fiber to obtain a fiberboard.

25. The method of claim 24, wherein the compressing in step (2) is performed with a hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press.

26. The method of claim 24, wherein the fiberboard is low-density fiberboard (LDF), medium-density fiberboard (MDF), or high-density fiberboard (HDF).49MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 27. A method of making a composite fiberboard, the method comprising:(1) providing the keratin-rich gel prepared according to the method of any one of claims 1-15;(2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture;(3) providing the residual fiber prepared according to the method of any one of claims 1-15; and(4) adding the residual fiber to the mixture, followed by compressing to obtain a composite fiberboard.

28. The method of claim 27, wherein the compressing in step (4) is performed with a hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press.

29. The method of claim 27, wherein the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof.

30. The method of any one of claims 27-29, wherein the ratio of the keratin-rich gel to the residual fiber is from about 0: 1 to about 1 :0.

31. The method of any one of claims 27-30, wherein increasing the ratio of the keratin-rich gel to the residual fiber decreases porosity and water absorption of the composite fiberboard.

32. The method of any one of claims 27-31, wherein the ratio of the chemical cross-linker to the keratin-rich gel is from about 0: 1 to about 1:1.

33. The method of any one of claims 27-32, wherein increasing the ratio of the chemical cross-linker to the keratin-rich gel improves mechanical strength of the composite fiberboard.

34. A method of making a coated fiberboard, the method comprising:(1) providing the residual fiber prepared according to the method of any one of claims 1-15;50MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 (2) compressing the residual fiber to obtain a fiberboard;(3) providing the keratin-rich gel prepared according to the method of any one of claims 1-15; and(4) coating the fiberboard with the keratin-rich gel, followed by curing to a obtain a coated fiberboard.

35. The method of claim 34, wherein the compressing in step (2) is performed with a hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press.

36. The method of claim 34, wherein the coating in step (4) is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

37. A method of making a coated composite fiberboard, the method comprising:(1) providing the keratin-rich gel prepared according to the method of any one of claims 1-15;(2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture;(3) providing the residual fiber prepared according to the method of any one of claims 1-15;(4) adding the residual fiber to the mixture, followed by compressing to obtain a composite fiberboard; and(5) coating the composite fiberboard with the keratin-rich gel, followed by curing to obtain a coated composite fiberboard.

38. The method of claim 37, wherein the compressing in step (4) is performed with a hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press.

39. The method of claim 37, wherein the coating in step (5) is achieved by spraying, dipping, painting, roll coating, or a combination thereof.51MEl\59581655.vlAttorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 40. The method of claim 37, wherein the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof.

41. A method of making a coated composite fiberboard, the method comprising:(1) providing the keratin-rich gel prepared according to the method of any one of claims 1-15;(2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture;(3) providing the residual fiber prepared according to the method of any one of claims 1-15;(4) adding the residual fiber to the mixture, followed by compressing to obtain a composite fiberboard; and(5) coating the composite fiberboard with the mixture from step (2), followed by curing to obtain a coated composite fiberboard.

42. The method of claim 41, wherein the compressing in step (4) is performed with a hydraulic press, hydraulic heat press, mechanical press, or mechanical heat press.

43. The method of claim 41, wherein the coating in step (5) is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

44. The method of claim 41, wherein the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof.

45. A method of making a coated felt or a coated wool textile, the method comprising:(1) providing the keratin-rich gel prepared according to the method of any one of claims 1-15;(2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture;52MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 (3) providing a felt or a wool textile; and(4) coating the felt or the wool textile with the keratin-rich gel, followed by curing to obtain a coated felt or a coated wool textile.

46. The method of claim 45, wherein the coating in step (4) is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

47. The method of claim 45, wherein the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof.

48. A method of making a coated felt or a coated wool textile, the method comprising:(1) providing the keratin-rich gel prepared according to the method of any one of claims 1-15;(2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture;(3) providing a felt or a wool textile; and(4) coating the felt or the wool textile with the mixture from step (2), followed by curing to obtain a coated felt or a coated wool textile.

49. The method of claim 48, wherein the coating in step (4) is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

50. The method of claim 48, wherein the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof.

51. A method of making a coated felt or a coated wool textile, the method comprising:(1) providing the keratin-rich gel prepared according to the method of any one of claims 1-15;(2) mixing the keratin-rich gel with a solution comprising about 0.1% wt to about 100% wt of a chemical cross-linker to obtain a mixture;53MEl\59581655.vlAtorney Docket No.: 117823-38120Harvard Reference No.: HU 9934 (3) providing a felt or a wool textile;(4) treating the felt or the wool textile with an alkaline solution at about 60 °C for about 24 hours to obtain a hydrolyzed felt or a hydrolyzed wool textile;(5) rinsing the hydrolyzed felt or the hydrolyzed wool textile with deionized or distilled water to a neutral pH of about 6.5 to about 7.5 and obtain a rinsed felt or a rinsed wool textile; and(6) coating the rinsed felt or the rinsed wool textile with the mixture from step (2), followed by curing to obtain a coated felt or a coated wool textile.

52. The method of claim 51, wherein the coating in step (6) is achieved by spraying, dipping, painting, roll coating, or a combination thereof.

53. The method of claim 51, wherein the chemical cross-linker is selected from the group consisting of citric acid, glycolic acid, lactic acid, polyacrylic acid, transglutaminases, and calcium chloride, and combinations thereof.

54. The method of any one of claims 51-53, wherein the alkaline solution in step (4) is an aqueous solution of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium sulfide, ammonia, or a combination thereof.

55. The method of any one of claims 51-54, wherein the concentration of the alkaline solution in step (4) is about 0.04 N, about 0.06 N, about 0.08 N, about 0.1 N, about 0.12 N, about 0.14 N, about 0.16 N, or about 0.2 N.

56. The method of claim 51, wherein the alkaline solution in step (4) is an aqueous solution comprising about 0.1 N sodium hydroxide.54MEl\59581655.vl

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