Porous alpha-1, 3-glucan compositions

Abstract

Disclosed herein are compositions comprising an aerogel or a hydrogel. The aerogel or hydrogel comprises a water insoluble alpha-glucan and a metal oxide. At least about 50% of the glycosidic bonds of the water-insoluble alpha-glucan are alpha-1, 3 bonds, and the metal oxide is selected from the group consisting of calcium oxide, magnesium oxide, titanium dioxide or any other suitable metal oxide. Also disclosed are methods of producing the aerogels and hydrogels, as well as methods of using these materials, as in absorption techniques. Other types of materials containing a water insoluble alpha-glucan are also disclosed.

Description

[0001] This application claims the benefit of U.S. Provisional Applications Nos. 63 / 511,292 (filed June 30, 2023), 63 / 511,286 (filed June 30, 2023) and 63 / 573,627 (filed April 3, 2024), each of which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure pertains to the field of polysaccharides. For example, this disclosure relates to porous compositions comprising insoluble α-glucan having α-1,3 glycosidic bonds. Aerogels and hydrogels are examples of porous compositions herein. Background Technology

[0003] Driven by the desire to use polysaccharides in a variety of applications, researchers have explored biodegradable polysaccharides that can be economically manufactured from renewable sources. One such polysaccharide is α-1,3-glucan, which is an insoluble dextran polymer characterized by having α-1,3-glycosidic bonds. For example, this polymer has been prepared using glucosyltransferases isolated from *Streptococcus salivarius* (Simpson et al., *Microbiology* 141:1451-1460, 1995). Also, for example, U.S. Patent No. 7,000,000 discloses the preparation of spun fibers from enzymatically produced α-1,3-glucan. A variety of other dextran materials have also been investigated for the development of new or enhanced applications. For example, U.S. Patent Application Publication No. 2015 / 0232819 discloses the enzymatic synthesis of several insoluble dextrans having mixed α-1,3 and α-1,6 bonds.

[0004] Aerogels are solid porous materials derived from gels that have been treated to replace their liquid contents with air. Typically, aerogels can contain at least about 99 wt% air, thus classifying them as ultralight materials. For example, due to their high surface area and porosity, aerogels can be used in applications such as absorption / adsorption, drug delivery, and catalysis, while their insulating properties also make them suitable for insulation and packaging applications. Various dextran polymers, such as cellulose and chitosan, have previously been tested in synthetic aerogels; however, these and other polysaccharide-based aerogels have generally been found to be prone to structural discontinuities, uneven pore distribution, and the formation of large pores, which can lead to significant shrinkage, structural collapse, and brittleness. These characteristics can adversely affect the water retention capacity of aerogels. Therefore, aerogels formulated with products that allow for better functionality are desirable. This paper discloses aerogels containing α-1,3-glucan, for example, to help address this need. Summary of the Invention

[0005] In one embodiment, this disclosure relates to a composition comprising an aerogel, wherein the aerogel comprises at least a water-insoluble α-glucan and a metal oxide, wherein at least about 50% of the glycosidic bonds of the insoluble α-glucan are α-1,3 bonds, and wherein the metal oxide is calcium oxide (CaO), magnesium oxide (MgO), or titanium dioxide (TiO2).

[0006] In another embodiment, this disclosure relates to an aqueous caustic alkali solution comprising (i) an aqueous caustic alkali solvent, (ii) a water-insoluble α-glucan and (iii) a metal hydroxide, wherein at least about 50% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 glycosidic bonds, wherein the water-insoluble α-glucan is soluble in the aqueous caustic alkali solvent and the metal hydroxide is insoluble in the aqueous caustic alkali solvent, and wherein the metal hydroxide is calcium hydroxide, magnesium hydroxide or titanium hydroxide.

[0007] In another embodiment, this disclosure relates to a method / process for producing the aerogel described herein, the method comprising: (a) providing an aqueous caustic alkali solution described herein, (b) converting the aqueous caustic alkali solution into a desired form, (c) chemically or ionicly modifying the aqueous caustic alkali solvent such that water-insoluble α-glucan and metal hydroxide are insoluble in the solvent, thereby producing a hydrogel, and (d) removing all or most of the water from the hydrogel, thereby producing an aerogel. Attached Figure Description

[0008] Figure 1 This figure illustrates a typical scheme used in this paper for the synthesis of hybrid hydrogels and hybrid aerogels. Reference examples are provided.

[0009] Figure 2 SEM images of pure dextran aerogel (a) and hybrid aerogels with magnesium oxide (b), calcium oxide (c), or titanium oxide (d). Each image contains a 50-μm reference bar and an inset with a 5-μm reference bar. Reference example.

[0010] Figure 3 Water absorption over time in hybrid and pure dextran aerogels. Insets show water absorption of the aerogels under load. Legend: Pure dextran (Main plot: triangle with lowest line, as indicated; Inset: rhombus with lowest line, as indicated), MgO-dextran (circle), CaO-dextran (triangle), TiO2-dextran (square). Reference examples.

[0011] Figure 4Hybrid dextran and pure dextran aerogels absorb salt water over time. The inset shows the salt water absorption of the aerogels under load. Legend: Pure dextran (main image: diamond with the lowest line, as indicated; inset: square with the lowest line, as indicated), MgO-dextran (circle), CaO-dextran (triangle), TiO2-dextran (square). Reference examples.

[0012] Figure 5A Hybrid dextran and pure dextran aerogels absorb glycerol:water (1:10) (v / v) over time. Illustrations: Pure dextran (rhombus), MgO-dextran (round), CaO-dextran (triangular), TiO2-dextran (square). See reference examples.

[0013] Figure 5B Hybrid dextran and pure dextran aerogels under load and time-varying glycerol:water (1:1) (v / v) absorption. Illustrations: Pure dextran (rhombus), MgO-dextran (circle), CaO-dextran (triangle), TiO2-dextran (square). Reference examples.

[0014] Figure 5C The absorption of hybrid dextran (MgO-, CaO-, or TiO2-dextran) and pure (pure) dextran aerogels in glycerol:water (1:10, 1:1, or 5:1) (v / v) over 100 seconds was measured. Absorbency capacity was also measured in commercial diapers and commercial pads. Viscosities of each glycerol-water solution are listed. Detailed Implementation

[0015] All cited patent and non-patent literature disclosures are incorporated herein by reference in their entirety.

[0016] Unless otherwise disclosed, the term "a / an" as used herein is intended to cover one / an or more / multiple (i.e., at least one / an) of the features referenced.

[0017] If they exist, all ranges are inclusive and composable unless otherwise stated. For example, when listing the range “1 to 5” (i.e., 1-5), the listed range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1-2”, “1-2 and 4-5”, “1-3 and 5”, etc. Unless otherwise expressly indicated, the numerical values ​​of the various ranges in this disclosure are stated as approximate values, as the minimum and maximum values ​​within the stated ranges are preceded by the word “approximately”. In this way, typically, slightly higher and lower variables than the stated ranges can achieve substantially the same results as values ​​within these ranges. Moreover, these ranges are intended to be disclosed as continuous ranges including every value between the minimum and maximum values.

[0018] Each maximum numerical limit given throughout this specification is intended to include each lower numerical limit, as such lower numerical limit is explicitly stated herein. Each minimum numerical limit given throughout this specification will include each higher numerical limit, as such higher numerical limit is explicitly stated herein. Each numerical range given throughout this specification will include each narrower numerical range falling within such a wider numerical range, as such narrower numerical range is explicitly stated in its entirety herein.

[0019] It should be understood that, for clarity, certain features of this disclosure described above and below in the context of aspects / embodiments may also be provided in combination in a single element. Conversely, for brevity, various features of this disclosure described in the context of a single aspect / embodiment may also be provided individually or in any sub-combination; that is, where applicable, aspects / embodiments disclosed herein relate to all other aspects / embodiments of this disclosure, even if such applicability is not separately disclosed herein.

[0020] The term "dextran" as used herein refers to a type of polysaccharide, which is a polymer of glucose (polydextrose). Dextran may contain, for example, about 90% by weight, 91% by weight, 92% by weight, 93% by weight, 94% by weight, 95% by weight, 96% by weight, 97% by weight, 98% by weight, 99% by weight, or 100% by weight of glucose monomer units. An example of dextran in this document is α-glucan.

[0021] The terms “α-glucan”, “α-glucan polymer”, etc., are used interchangeably herein. α-glucan is a polymer comprising glucose monomer units linked together by α-glycosidic bonds. Typically, the glycosidic bonds of α-glucans herein are about 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% α-glycosidic bonds. An example of an α-glucan polymer herein is α-1,3-glucan.

[0022] Unless otherwise stated, the term "carbohydrate" and other similar terms herein refer to monosaccharides and / or disaccharides / oligosaccharides. "Disaccharide" as used herein refers to a carbohydrate having two monosaccharides linked by a glycosidic bond. "Oligosaccharide" as used herein can refer to a carbohydrate having, for example, 3 to 15 monosaccharides linked by a glycosidic bond. Oligosaccharides may also be referred to as "oligomers." Monosaccharides contained within a disaccharide / oligosaccharide (e.g., glucose and / or fructose) may be referred to as "monomer units," "monosaccharide units," or other similar terms.

[0023] The terms “α-1,3-glucan,” “poly-α-1,3-glucan,” and “α-1,3-glucan polymer” are used interchangeably herein. α-1,3-glucan is an α-glucan comprising glucose monomer units linked together by glycosidic bonds, wherein at least about 50% of the glycosidic bonds are α-1,3. In some aspects, α-1,3-glucan contains about or at least about 90%, 95%, or 100% α-1,3-glycosidic bonds. Most or all of the other bonds (if present) in α-1,3-glucan herein are typically α-1,6, although some bonds may also be α-1,2 and / or α-1,4. α-1,3-glucan herein is typically water-insoluble.

[0024] The terms "bond," "glycosidic linkage," and "glycosidic bond" refer to the covalent bonds that link sugar monomers within carbohydrate compounds (oligosaccharides and / or polysaccharides). Examples of glycosidic bonds include 1,6-α-D-glycosidic bonds (also referred to herein as "α-1,6"), 1,3-α-D-glycosidic bonds (also referred to herein as "α-1,3"), 1,4-α-D-glycosidic bonds (also referred to herein as "α-1,4"), and 1,2-α-D-glycosidic bonds (also referred to herein as "α-1,2"). The glycosidic linkage of dextran polymers in this article can also be referred to as a "glucosidic linkage." In this article, "α-D-glucose" is referred to as "glucose."

[0025] The glycosidic bond spectrum of α-glucan can be determined using any method known in the art. For example, it can be determined using nuclear magnetic resonance (NMR) spectroscopy (e.g., 13 C NMR and / or 1 Bond spectra can be determined using methods such as H NMR. These and other methods that can be used are disclosed, for example, Food Carbohydrates: Chemistry, Physical Properties, and Applications [ Food carbohydrates: chemical and physical properties and applications [This is from SW Cui, ed., Chapter 3, Structural Analysis of Polysaccharides, Taylor & Francis Group LLC, Pocaraton, Florida, 2005, which is incorporated herein by reference.]

[0026] The “molecular weight” of α-glucan in this article may be expressed as weight-average molecular weight (Mw) or number-average molecular weight (Mn), in Daltons (Da) or grams per mole. In some respects, molecular weight may be expressed as DPw (weight-average degree of polymerization) or DPn (number-average degree of polymerization). DPw and DPn are calculated by dividing the corresponding Mw or Mn by the molar mass of a monomer unit M1, respectively. For dextran polymers, M1 = 162.14. In some respects (e.g., oligosaccharides), molecular weight may sometimes be provided as “DP” (degree of polymerization), which simply refers to the amount of glucose contained in a single molecule of the α-glucan. Various methods for calculating these different molecular weight measurements are known in the art, such as high-performance liquid chromatography (HPLC), size exclusion chromatography (SEC), or gel permeation chromatography (GPC).

[0027] As used in this article, Mw = ΣNiMi 2 Mw is calculated as / ΣNiMi; where Mi is the molecular weight of a single chain i and Ni is the number of chains with that molecular weight. Besides SEC, the Mw of a polymer can be determined by other techniques such as static light scattering, mass spectrometry, MALDI-TOF (matrix-assisted laser desorption / ionization time-of-flight), small-angle X-ray or neutron scattering, or ultracentrifugation. As used herein, Mn can be calculated as Mn = ΣNiMi / ΣNi, where Mi is the molecular weight of chain i and Ni is the number of chains with that molecular weight. In addition to SEC, the Mn of a polymer can be determined by various colligative methods (such as vapor pressure permeation) and by end-group determination using spectroscopic methods (such as proton NMR, proton FTIR, or UV-Vis).

[0028] As used herein, the term "hydrogel" and similar terms refer to a two-phase material / composition that is a porous, permeable solid and typically contains at least 10% by weight or volume of an aqueous fluid ("interstitial aqueous fluid") (typically 100 wt% water, or an aqueous liquid of water and one or more other types of liquids, such as a suitable polar organic solvent [e.g., ethanol, isopropanol]). The hydrogel solid component is a water-insoluble three-dimensional network that contains at least α-1,3-glucan and a metal oxide, such as calcium hydroxide [Ca(OH)2], magnesium hydroxide [Mg(OH)2], or titanium hydroxide [Ti(OH)4] (or any other hydroxide of an alkaline earth metal or transition metal suitable for producing a hydrogel of α-1,3-glucan).

[0029] As used herein, the terms “aerogel,” “solid foam,” “sponge,” “solid sponge,” etc., refer to porous materials / compositions derived from aqueous gels (hydrogels), wherein the liquid component (typically only water, but optionally further comprising one or more other types of liquid) has been replaced by a gas (e.g., standard atmospheric air). Thus, aerogels are typically dry / dried compositions, although they can be made wet for water absorption applications. Aerogels as described herein are generally nanoporous materials / compositions possessing a variety of properties, such as low density, low thermal conductivity, enhanced strength / stiffness, and / or high specific internal surface area. Aerogels disclosed herein contain at least α-1,3-glucan and a metal oxide, such as calcium oxide (CaO), magnesium oxide (MgO), or titanium dioxide (TiO2) (or any other oxide of an alkaline earth metal or transition metal suitable for producing aerogels of α-1,3-glucan). Given this combination of metal oxide and α-1,3-glucan, such aerogel may optionally be described herein as a “hybrid α-1,3-glucan aerogel” (and similar terms), in contrast to aerogels containing only α-1,3-glucan (“pure” or “pure” α-1,3-glucan aerogels).

[0030] The terms “particles,” “microparticles,” and similar terms are used interchangeably herein and refer to the smallest identifiable unit in a particulate system. In some aspects, a composition may be described as having been “crushed,” meaning that the composition has been reduced from a larger size to particles (e.g., by crushing, grinding, milling, and / or any other suitable means). In some aspects, particle size may refer to the diameter and / or length of the longest particle size. Average size may be based on, for example, the average diameter and / or length of at least 50, 100, 500, 1000, 2500, 5000, or 10000 or more particles. Particle size as used herein may be measured by methods including light scattering or electrical impedance variation (e.g., using a Coulter counter), such methods as those described, for example, in any of U.S. Patent Nos. 6,091,492, 6,741,350, or 9,297,737 (each incorporated herein by reference). Particle size as used herein may optionally be defined by “D…” 10 “D” 50 “D” 90 "Equivalent representation; for example, D" 50 The value is such that 50% by weight of the particles in the composition (e.g., the powder of aerogel in this article) have a diameter lower than this diameter, and 50% by weight of the particles have a diameter greater than this diameter.

[0031] In this article, the terms "hydrogen bond," "hydrogen bonding," etc., refer to electromagnetic attraction that is not a covalent bond, ionic bond, or van der Waals force. Hydrogen bonds are weaker than ionic and covalent bonds, but stronger than van der Waals forces. Typically, in this article, the hydrogen atom involved in the hydrogen bond is directly bonded to the (hydroxyl) oxygen atom of the glucose monomer unit of α-glucan, which interacts electrostatically with the oxygen atom of the metal oxide. This hydrogen bonding can optionally be described as intermolecular, as it occurs between the α-glucan molecule and the metal oxide molecule.

[0032] As used herein, the terms “aqueous liquid,” “aqueous fluid,” “aqueous conditions,” “aqueous reaction conditions,” “aqueous environment,” and “aqueous system” can refer to water or an aqueous solution. An “aqueous solution” as used herein may contain one or more dissolved salts, wherein in some respects the maximum total salt concentration may be about 3.5 wt%. While aqueous liquids as used herein typically contain water as the sole solvent, aqueous liquids may optionally contain one or more other solvents miscible with water (e.g., polar organic solvents). Thus, an aqueous solution may contain a solvent having at least about 10 wt% water.

[0033] For example, the term "aqueous composition" as used herein refers to a liquid component comprising about or at least about 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 99, or 100 wt% water. Examples of aqueous compositions include, for example, mixtures, solutions, dispersions (e.g., colloidal dispersions), suspensions, and emulsions.

[0034] α-glucans described herein as “insoluble,” “aqueous-insoluble,” “water-insoluble,” or similar terms (e.g., α-1,3-glucans with a DP of 8 or higher) are insoluble (or not significantly soluble) in water or other aqueous conditions, optionally wherein such aqueous conditions are a pH of 4-9 (e.g., pH 6-8) and / or a temperature of about 1°C to 130°C (e.g., 20°C-25°C). In some respects, less than 1.0 g (e.g., an undetectable amount) of the aqueously insoluble α-glucans described herein dissolves in 1000 mL of such aqueous conditions (e.g., water at 23°C). In contrast, α-glucans described herein as “soluble,” “aqueous-soluble,” or “water-soluble,” such as certain oligosaccharides (e.g., α-1,3-glucans with a DP of less than 8), are significantly soluble under these conditions.

[0035] In this article, “doped solution,” “dopant,” “caustic solution,” “basic solution,” “alkaline solution,” etc., refer to a solution in which at least water-insoluble α-glucan (e.g., insoluble in aqueous solutions at pH 4–9) is dissolved (typically having an aqueous solution with pH ≥ 11).

[0036] The terms “freeze-drying”, “lyophilization”, etc., as used herein refer to a process in which a wet composition (e.g., a hydrogel as described herein) (e.g., wetted with water, a polar organic solvent, or a combination thereof) is rapidly frozen (freezing step) and then subjected to a high vacuum (to provide a lower pressure) to remove the frozen water by sublimation (primary drying step). Freeze-drying as described herein may optionally include a secondary drying step, wherein the temperature is raised to a higher level than in the primary drying stage (and the pressure is typically further reduced).

[0037] The terms “supercritical drying,” “critical point drying,” etc., used herein refer to the process of converting a liquid (e.g., water, a polar organic solvent, or a combination thereof) in a wet composition (e.g., a hydrogel in this context) into a gas in the absence of surface tension and capillary stress. For example, supercritical drying can be performed using supercritical carbon dioxide (CO2). Supercritical CO2 is the fluid state of CO2 in which it is maintained at or above its critical temperature and critical pressure.

[0038] As used herein, the terms “sequence identity”, “identity”, etc., relating to polypeptide amino acid sequences (e.g., polypeptide amino acid sequences of glucosyltransferases) may be as defined and determined as in U.S. Patent Application Publication No. 2017 / 0002336 (which is incorporated herein by reference).

[0039] As a feature of certain embodiments, various polypeptide amino acid sequences are disclosed herein. Variants of these sequences that are at least about 70%-85%, 85%-90%, or 90%-95% identical to the sequences disclosed herein may be used or referenced. Alternatively, the variant amino acid sequences may have at least 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 99.5% identity with the sequences disclosed herein. The variant amino acid sequence has the same function / activity as the disclosed sequence, or has at least about 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of the function / activity of the disclosed sequence.

[0040] The compositions described herein, such as aerogels (which are “dry” or “dried”), typically contain less than about 3, 2, 1, 0.5, or 0.1 wt% water.

[0041] As used herein, the term "viscosity" refers to a measure of the degree to which a fluid (aqueous or non-aqueous) resists forces that tend to cause it to flow. Various units of viscosity may be used in this document, including, for example, centipoise (cP, cps) and pascal-second (Pa·s). One centipoise is one-hundredth of a poise; one poise is equal to 0.100 kg·m³. -1 ·s -1 In some respects, viscosity can be reported as “intrinsic viscosity” (IV, η, in dL / g); this term refers to a measure of the contribution of the dextran polymer to the viscosity of a liquid (e.g., a solution) containing the dextran polymer. IV measurements herein can be obtained, for example, using any suitable method, as disclosed in U.S. Patent Application Publication Nos. 2017 / 0002335, 2017 / 0002336, or 2018 / 0340199, or Weaver et al. (J. Appl. Polym. Sci. [Applied Polymer Science] 35:1631-1637) or Chun and Park (Macromol. Chem. Phys. [Polymer Chemistry and Physics] 195:701-711), all of which are incorporated herein by reference. For example, IV can be measured in part by dissolving the dextran polymer in DMSO of LiCl having about 0.9 to 2.5 wt% (e.g., 1, 2, 1-2 wt%) at about 100°C for at least 2, 4, or 8 hours. IV as described herein can optionally be used as a relative measure of molecular weight.

[0042] As used herein, the terms "absorb" and similar terms refer to the action of taking up or soaking up a liquid (e.g., an aqueous liquid). For example, the absorption of a composition as disclosed herein can be measured based on the water absorption capacity as disclosed herein. "Absorbent" herein refers to a product / composition that exhibits absorption when placed in contact with water or other aqueous compositions / liquids.

[0043] The term "under load" and similar terms used herein describe conditions in which pressure or weight is applied to the composition or product herein. Typically, when applied to a composition, such conditions can reduce the composition's ability to absorb aqueous liquids, or, if aqueous liquids have already been absorbed by the composition, conditions under load can serve to reduce the amount of aqueous liquids absorbed (e.g., some of the absorbed aqueous liquids may be forced out of the composition under load).

[0044] The terms "polar organic solvent" and "water-miscible organic solvent" (and similar terms) are used interchangeably herein. Polar organic solvents are soluble in water or aqueous solutions. Therefore, polar organic solvents do not separate into different phases when added to water or aqueous solutions. Polar organic solvents contain carbon and at least one heteroatom (i.e., a non-carbon or non-hydrogen atom), such as oxygen, nitrogen, sulfur, or phosphorus. This contrasts with nonpolar organic solvents, which typically contain only carbon and hydrogen atoms. Polar organic solvents typically have a dielectric constant greater than about 4. Polar organic solvents contain dipoles due to polar bonds.

[0045] The term "proton polar organic solvent" (and similar terms) used herein refers to a polar organic solvent having one or more suitably unstable hydrogen atoms capable of forming hydrogen bonds. Proton polar organic solvents typically contain hydrogen atoms bonded to atoms with electronegative properties; for example, one or more OH, NH, and / or SH bonds are present.

[0046] The term "aprotic polar organic solvent" (and similar terms) used herein refers to a polar organic solution that does not have suitable, unstable hydrogen atoms capable of forming hydrogen bonds. Aprotic polar organic solvents do not contain hydrogen atoms bonded to electronegative atoms; for example, OH, NH, or SH bonds are absent.

[0047] The terms "home care products" or "household care products" typically refer to products, goods, and services relating to the handling, cleaning, care, and / or conditioning of the home and its interior. This includes, for example, chemicals, compositions, products, or combinations thereof intended for use in such care.

[0048] The term "personal care products" and similar terms typically refer to products, goods, and services relating to the treatment, cleaning, washing, care, or conditioning of a person. This includes, for example, chemicals, compositions, products, or combinations thereof used in such care.

[0049] The term "medical product" and similar terms typically refer to products, goods and services related to the diagnosis, treatment and / or care of patients.

[0050] The term "industrial product" and similar terms typically refer to products, goods and services used in industrial and / or institutional settings, but not typically used by individual consumers.

[0051] In this article, the terms “pharmaceutical product,” “medicine,” “medication,” “drug,” or similar terms refer to compositions used to treat a disease or injury and which may be administered orally or parenterally.

[0052] The terms “percent by volume percent”, “vol %”, and “v / v %” are used interchangeably in this document. The volume percentage of solute in a solution can be determined using the following formula: [(solute volume) / (solution volume)] × 100%.

[0053] The terms “percent by weight (wt%)”, “weight-weight percentage (% w / w)”, etc., are used interchangeably herein. For example, weight percentage refers to the percentage of a material by mass when it is contained in a composition, mixture, or solution.

[0054] The terms “weight / volume percentage”, “w / v%”, etc., are used interchangeably herein. Weight / volume percentage can be calculated as: ((mass of material [g]) / (total volume of material plus the liquid in which the material is placed [mL])) × 100%. The material may be insoluble in the liquid (i.e., a solid phase in a liquid phase, as in the case of a dispersion) or soluble in the liquid (i.e., a solute dissolved in the liquid).

[0055] The term "separate" means a substance (or process) that exists in a form not found in nature or in an environment not found in nature. Non-limiting examples of separated substances include any aerogels, hydrogels, or caustic solutions described herein. The embodiments disclosed herein are believed to be synthetic / artificial (impossible to manufacture or practice without human intervention / participation) and / or have properties not naturally occurring.

[0056] As used herein, the term "increased" can mean an amount or activity that is at least about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 50%, 100%, or 200% greater than that compared to the increased amount or activity. The terms "increased," "enhanced," "strengthened," "greater than," "improved," etc., are used interchangeably herein.

[0057] Some aspects of this disclosure relate to a composition / product comprising at least an aerogel (or, for example, foam / solid foam, or sponge / solid sponge), wherein the aerogel comprises at least a water-insoluble α-glucan and a metal oxide, wherein at least about 50% of the glycosidic bonds of the insoluble α-glucan are α-1,3 bonds, and wherein the metal oxide is calcium oxide (CaO), magnesium oxide (MgO), or titanium dioxide (TiO2) (or any other suitable oxide of an alkaline earth metal or transition metal).

[0058] In some respects, insoluble α-glucans contain about or at least about 50%, 60%, 70%, 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% α-1,3-glycosidic bonds (i.e., the α-glucan is α-1,3-glucan). Therefore, in some respects, insoluble α-glucans have about, or less than about 50%, 40%, 30%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, or 0% of non-α-1,3-glycosidic bonds. Typically, the non-α-1,3-glycosidic bonds are predominantly or entirely α-1,6-glycosidic bonds. In some respects, insoluble α-glucans do not have a branching point or have a branching point of less than about 5%, 4%, 3%, 2%, or 1% (as a percentage of glycosidic bonds in α-glucans).

[0059] In some respects, the DPw, DPn, or DP of the insoluble α-glucan can be about, at least about, or less than about 10, 15, 25, 50, 75, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2500, 3000, 3500, or 4000. DPw, DPn, or DP can optionally be expressed as a range between any two of these values. For example only, DPw, DPn, or DP can be approximately 50-1600, 100-1600, 200-1600, 300-1600, 400-1600, 500-1600, 600-1600, 700-1600, 50-1250, 100-1250, 200-1250, 300-1250, 400-1250, 500-1250, 600-1250, 700 -1250, 50-1000, 100-1000, 200-1000, 300-1000, 400-1000, 500-1000, 600-1000, 700-1000, 50-900, 100-900, 200-900, 300-900, 400-900, 500-900, 600-900, 700-900, 600-800, or 600-750. As an additional example only, DPw, DPn, or DP can be approximately 15-100, 25-100, 35-100, 15-80, 25-80, 35-80, 15-60, 25-60, 35-60, 15-55, 25-55, 35-55, 15-50, 25-50, 35-50, 35-45, 35-40, 40-100, 40-80, 40-60, 40-55, 40-50, 45-60, 45-55, 45-50, 15-35, 20-35, 15-30, or 20-30. As an additional example only, DPw, DPn, or DP can be approximately 100-600, 100-500, 100-400, 100-300, 200-600, 200-500, 200-400, or 200-300.In some respects, insoluble α-glucans can have high molecular weights as reflected by high intrinsic viscosity (IV); for example, IV can be about or at least about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 6-8, 6-7, 6-22, 6-20, 6-17, 6-15, 6-12, 10-22, 10-20, 10-17, 10-15, 10-12, 12-22, 12-20, 12-17, or 12-15 dL / g (for comparison purposes, note that insoluble α-glucans having at least 90% (e.g., about 99% or 100%) α-1,3 bonds and about 800 DPw have an IV of about 2-2.5 dL / g). For example, IV in this article can be measured as in an insoluble α-glucan polymer dissolved in DMSO having about 0.9 to 2.5 wt% (e.g., 1, 2, 1-2 wt%) LiCl.

[0060] The insoluble α-glucan used herein may be as disclosed in, for example, the following documents (e.g., molecular weight, bond spectrum, and / or production method): U.S. Patent Nos. 7,000,000, 8,871,474, 10,301,604, or 10,260,053, or U.S. Patent Application Publication Nos. 2019 / 0112456, 2019 / 0078062, 2019 / 0078063, ... References 8 / 0340199, 2018 / 0021238, 2018 / 0273731, 2017 / 0002335, 2015 / 0232819, 2015 / 0064748, 2020 / 0165360, 2020 / 0131281, 2019 / 0276806, or 2019 / 0185893, each incorporated herein by reference. Insoluble α-glucan can be produced, for example, by an enzymatic reaction comprising at least water, sucrose, and a glucosyltransferase for the synthesis of insoluble α-glucan. Glucosyltransferases, reaction conditions, and / or methods intended for the production of insoluble α-glucan can be disclosed as in any of the foregoing references.

[0061] In some aspects, the glucosyltransferase used to generate the insoluble α-glucan described herein may comprise an amino acid sequence that is 100% identical or at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 98.5%, 99%, or 99.5% identical to amino acid residues 55-960 of SEQ ID NO:2, SEQ ID NO:65, SEQ ID NO:30, SEQ ID NO:28, or SEQ ID NO:20, and has glucosyltransferase activity; these amino acid sequences are disclosed in U.S. Patent Application Publication No. 2019 / 0078063, which is incorporated herein by reference. It should be noted that glucosyltransferases containing amino acid residues 55-960 of SEQ ID NO:2, 4, 8, 10, 14, 20, 26, 28, 30, 34, or SEQ ID NO:4, residues 54-957 of SEQ ID NO:65, residues 55-960 of SEQ ID NO:30, residues 55-960 of SEQ ID NO:28, or residues 55-960 of SEQ ID NO:20 can synthesize insoluble α-glucans containing at least about 90% (about 100%) of α-1,3 bonds.

[0062] The insoluble α-glucans described herein typically do not exhibit any chemical derivatization (e.g., etherification, esterification, phosphorylation, sulfation, oxidation, carbamate esterification) (e.g., the hydrogen atom of the hydroxyl group in the dextran is not substituted by a non-sugar chemical group). However, in some respects, the insoluble α-glucans can be charged (e.g., cationic or anionic) derivatives of the α-glucans disclosed herein. Such derivatives typically have a DoS of less than about 0.3, 0.25, 0.2, 0.15, 0.1, or 0.05. The type of derivative can be any of the aforementioned derivatives (e.g., ethers, esters). Typically, the insoluble α-glucans described herein are enzymatically derivatized in inert containers (typically under cell-free conditions) and are not derived from cell walls (e.g., fungal cell walls).

[0063] In some respects, the metal oxide may be calcium oxide (CaO), magnesium oxide (MgO), or titanium dioxide (TiO2). For illustrative purposes, it should be noted that titanium is a transition metal, and calcium and magnesium are alkaline earth metals. Therefore, it is contemplated that the metal oxide described herein may be another type of alkaline earth metal oxide or transition metal oxide, for example, suitable for forming aerogels with the water-insoluble α-glucan of this disclosure. Typically, the aerogels described herein have one metal oxide, but in some cases, the aerogel may have two or more metal oxides (e.g., CaO and MgO, CaO and TiO2, MgO and TiO2). Considering how aerogels can be generated (e.g., as disclosed herein), the metal oxides described herein (such as those contained in the aerogel) may optionally be described as in-situ generated metal oxides.

[0064] The metal oxide component of the aerogels disclosed herein typically interacts with water-insoluble α-glucan via hydrogen bonding. Hydrogen bonding can be multivalent, for example, as in the case of TiO2 used as the metal oxide. The aerogels or hydrogels described herein typically do not contain any covalent crosslinks, either between α-glucan molecules (intramolecular or intermolecular) or between α-glucan and the metal oxide or metal hydroxide.

[0065] The aerogel described herein may contain, for example, about 20, 15, 10, 7.5, 6, 5, 4, 3, 2.5, 2, 1, 0.5, 0.5-10, 0.5-5, 0.5-4, 0.5-3, 0.5-2.5, 1-10, 1-5, 1-4, 1-3, 1-2.5, or 1.5-2.5 wt% of the metal oxides described herein (or combinations of the metal oxides described herein). The distribution of the metal oxides in the aerogel is typically uniform. In some aspects, the balance by weight of the aerogel is water-insoluble α-glucan (i.e., such an aerogel can be described as consisting of water-insoluble α-glucan and metal oxides). However, in some aspects, in addition to water-insoluble α-glucan and metal oxides, the aerogel may also contain one or more other components (solids). In some aspects, the aerogel may contain about or at least about 80, 85, 90, 92.5, 94, 95, 96, 97, 97.5, 98, 99, or 99.5 wt% of water-insoluble α-glucan. In some aspects, the aerogel does not contain polyurethane or any other organic polymer (other than the insoluble α-glucan), and / or does not contain silica. The aforementioned amounts (wt%) may refer to the dry solids of the aerogel. Any solid components of the aerogel described herein typically originate from their inclusion (or in-situ generation) during the preparation of the aerogel (i.e., solid components are typically not present due to absorption into the aerogel, such as from the use of the aerogel in an absorption method and then its drying). Although aerogels produced as described herein (not yet used in an absorption method) are typically dry / dried (before their use in the aqueous liquid absorption method described herein), they may optionally contain trace amounts of water (e.g., absorbed from the atmosphere) (e.g., ≤ 2, 1, 0.5, or 0.1 wt% of the aerogel). The hydrogel described herein may contain any of the aforementioned amounts of water-insoluble α-glucan and metal hydroxides that may be used to provide any of the aforementioned metal oxides, wherein the amounts are based on dry solids (dsb) (or alternatively referred to as dry heavy basis, dwb).

[0066] The aerogels described herein are porous, typically having a porosity of about or at least about 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.8%, or 99.9%. The porosity percentage described herein can be determined by dividing the total volume of all aerogel pores by the total volume of the aerogel itself and multiplying by 100%. The aerogels disclosed herein typically have an open-pore structure. For example, the pores of the aerogels described herein can be continuous or semi-continuous (e.g., at least about 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the pores are continuous with at least one adjacent pore) (any two pores can be described as continuous with each other if an open channel connecting them exists). The pores described herein are typically present in a uniform manner throughout the aerogel. Typically, the aerogels described herein do not contain closed-pore structures (i.e., completely closed pores that are discontinuous with any adjacent pores), or have less than 5% or 1% of pores that are closed pores.

[0067] In some aspects of α-dextran aerogels containing TiO2, the pore volume / aerogel mass can be approximately 0.10–0.15, 0.11–0.15, 0.12–0.15, 0.13–0.15, 0.10–0.14, 0.11–0.14, 0.12–0.14, or 0.13–0.14 cm⁻¹ 3 / g. In some aspects of α-dextran aerogels containing CaO, the pore volume / aerogel mass can be about 0.055-0.065, 0.058-0.065, 0.060-0.065, 0.055-0.063, 0.058-0.063, or 0.060-0.063 cm⁻¹. 3 / g. In some aspects of α-dextran aerogels containing MgO, the pore volume / aerogel mass can be approximately 0.082–0.092, 0.085–0.092, 0.082–0.090, or 0.085–0.090 cm³. 3 / g. In some respects, pure α-1,3-glucan aerogels have a density of approximately 0.075 cm⁻¹. 3 / g pore volume / aerogel mass. The pore volume of the aerogel can be measured using any suitable method, such as the method disclosed in the examples below. The aforementioned pore volume / mass value can optionally characterize hybrid α-glucan aerogels having about 2 wt% of the listed metal oxides.

[0068] In some aspects of α-glucan aerogels containing TiO2, the specific surface area can be approximately 75-90, 78-90, 80-90, 75-85, 78-85, or 80-85 m². 2 / g. In some aspects of α-glucan aerogels containing CaO, the specific surface area can be about 30-40, 35-40, 30-38, or 35-38 m². 2 / g. In some aspects of α-glucan aerogels containing MgO, the specific surface area can be about 48-58, 50-58, 48-55, or 50-55 m². 2 / g. In some respects, pure α-1,3-glucan aerogel has approximately 44.7 m... 2 Specific surface area per g. The specific surface area of ​​porous materials (such as aerogels in this paper) refers to the interstitial surface area of ​​the voids and / or pores per unit mass of the porous material. The specific surface area of ​​aerogels can be measured using any suitable method, such as the Brunauer-Emmett-Teller (BET) measurement (e.g., according to the examples below). Specific surface area values ​​can optionally characterize hybrid α-glucan aerogels having about 2 wt% of the listed metal oxides.

[0069] In some aspects, the composition / product comprises a pulverized (i.e., micronized) aerogel. The aerogel may optionally be provided in the form of powder or other particulate matter (e.g., fine particles, dust, granules, flakes). The methods for producing the aerogel described herein may optionally further include a step of pulverizing the aerogel, such as by grinding, milling, cutting, shredding, dicing, or other actions used for pulverizing solids. In some respects, the diameter or longest dimension of aerogel particles can be about or at least about 5, 10, 25, 50, 75, 100, 125, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 5-125, 5-250, 5-500, 5-1000, 50-125, 50-250, 50-500, 50-1000, 100-125, 100-250, 100-500 or 100-1000 micrometers.

[0070] The aerogels or hydrogels, or compositions comprising any of these, described herein are typically biodegradable. After testing at 15, 30, 45, 60, 75, or 90 days, for example, this biodegradability can be determined as, for example, by the carbon dioxide emission test method (OECD Guideline 301B, incorporated herein by reference), to be about, at least about, or at most about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 5%–60%, 5%–80%, 5%. -90%, 40%-70%, 50%-70%, 60%-70%, 40%-75%, 50%-75%, 60%-75%, 70%-75%, 40%-80%, 50%-80%, 60%-80%, 70%-80%, 40%-85%, 50%-85%, 60%-85%, 70%-85%, 40%-90%, 50%-90%, 60%-90%, or 70%-90%, or any value between 5% and 90%.

[0071] In some respects, aerogels are heat-resistant. For example, aerogels can withstand degradation when exposed to temperatures of about or up to about 210°C, 225°C, 250°C, 275°C, 300°C, 325°C, 350°C, 210°C–250°C, 225°C–250°C, 210°C–300°C, or 225°C–300°C. This heat resistance can refer to aerogels containing, for example, about 1, 1.5, 2, 2.5, 3, 4, 1–4, 1–3, or 1.5–2.5 wt% of the metal oxides disclosed herein; other metal oxide content levels also considered herein. Thermal degradation can manifest as a weight loss (e.g., about or at least about 50%, 60%, 70%, 80%, or 90%) after exposure to the aforementioned temperatures for a duration of about 0.5, 1, 2, 5, 10, 15, 30, or 60 minutes. The thermal degradation resistance of the aerogels described herein can be measured using any suitable method, such as those disclosed in the examples below.

[0072] In some respects, the hydrogel or aerogel comprises the water-insoluble α-glucan described herein that has been cross-linked using one or more cross-linking agents. Examples of cross-linking agents described herein include phosphoryl chloride (POCl3), polyphosphates, sodium trimetaphosphate (STMP), boron-containing compounds (e.g., boric acid, diborates, tetraborates such as tetraborate decahydrate, pentaborates, polymeric compounds such as Polybor®, alkali metal borates), multivalent metals (e.g., titanium-containing compounds such as titanium ammonium lactate, triethanolamine titanium, titanium acetylacetonate, or titanium polyhydroxy complexes; zirconium-containing compounds such as zirconium lactate, zirconium carbonate, zirconium acetylacetonate, zirconium triethanolamine, zirconium diisopropylamine lactate, or zirconium polyhydroxy complexes), glyoxal, glutaraldehyde, acetaldehyde, polyphenols, divinyl sulfone, epichlorohydrin, polyamide-epichlorohydrin (PAE), di- or poly- Monocarboxylic acids (e.g., citric acid, malic acid, tartaric acid, succinic acid, glutaric acid, adipic acid), dichloroacetic acid, polyamines, 1,2,7,8-diepoxyoctane, diethylene glycol dimethyl ether (diethylene glycol dimethyl ether), diglycidyl ethers (e.g., diglycidyl ether itself, ethylene glycol diglycidyl ether [EGDGE], 1,4-butanediol diglycidyl ether [BDGE], polyethylene glycol diglycidyl ether [PEGDE, such as PEG2000DGE], 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether [BADGE]), and triglycidyl ethers (e.g., trimethylolpropane triglycidyl ether). Other examples of suitable crosslinking agents are described in U.S. Patent Nos. 4,462,917, 4,464,270, 4,477,360, or 4,799,550, or U.S. Patent Application Publication No. 2008 / 0112907, each of which is incorporated herein by reference. Crosslinking agents are typically soluble in the aqueous caustic solvent described herein and function to crosslink α-glucan molecules also soluble in the caustic solvent. This crosslinking is typically covalent; that is, α-glucan molecules are chemically crosslinked with each other (via intermolecular crosslinking).

[0073] The aerogels disclosed herein are typically capable of absorbing water or another aqueous liquid. Therefore, in some aspects, the aerogel may further contain water or another aqueous liquid, wherein such water or aqueous liquid is absorbed by the aerogel (e.g., as would occur when a product containing the aerogel is used in the method of absorbing an aqueous liquid described herein). In some aspects, such an aerogel is under an applied load (e.g., as described below) (e.g., under compression).

[0074] In some respects, aqueous liquids comprise aqueous solutions, such as salt solutions (saltwater solutions). Salt solutions may optionally contain about 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 0.9, 1.0, 1.25, 1.5, 1.75, 2.0, 2.5, 3.0, 0.5-1.5, 0.5-1.25, 0.5-1.0, 0.75-1.5, 0.75-1.25, or 0.75-1.0 wt% of salt (such wt% values ​​typically refer to the total concentration of one or more salts). Examples of salts that may be used in the aqueous solutions described herein include one or more sodium salts (e.g., NaCl, Na₂SO₄). Other examples of salts include those having (i) aluminum, ammonium, barium, calcium, chromium (II or III), copper (I or II), iron (II or III), hydrogen, lead (II), lithium, magnesium, manganese (II or III), mercury (I or II), potassium, silver, sodium, strontium, tin (II or IV), or zinc cations, and (ii) Acetates, borates, bromates, bromides, carbonates, chlorates, chlorides, chlorites, chromates, ammonia, cyanides, dichromates, dihydrogen phosphates, ferrocyanides, ferrocyanides, fluorides, bicarbonates, hydrogen phosphates, bisulfates, hydrogen sulfide, bisulfites, hydrides, hydroxides, hypochlorites, iodates, iodides, nitrates, nitrides, oxalates, oxides, perchlorates, permanganates, peroxides, phosphates, phosphides, phosphites, silicates, stannates, stansites, sulfates, sulfides, sulfites, tartrates, or thiocyanate anions. Therefore, for example, any salt having a cation from (i) above and an anion from (ii) above can be in an aqueous liquid as disclosed in this invention.

[0075] For example, the aqueous liquid that can be absorbed by the aerogel described herein may have a viscosity of about, at least about, or less than about 1, 5, 10, 15, 20, 25, 50, 75, 100, 125, 1-125, 1-100, 1-50, 1-25, 1-15, 1-10, 1-5, 5-125, 5-100, 5-50, 5-15, 5-25, or 5-10 centipoise (cps, cP). The viscosity of the aqueous liquid described herein may be measured at any temperature, for example, between about 3°C ​​and about 80°C (e.g., 4°C-30°C, 15°C-30°C, 15°C-25°C) or at any specific temperature of the aqueous composition disclosed herein. Viscosity is typically measured at atmospheric pressure (about 760 Torr) or at ±10% of that pressure. Viscosity can be measured using, for example, a viscometer or rheometer, and can optionally be measured in, for example, at values ​​of about 0.1, 0.3, 0.5, 1.0, 3, 5, 10, 50, 100, 200, 500, 0.1-500, 0.1-100, 1.0-500, or 1.0-100 s.-1 Measured at a shear rate (rotational shear rate) of (1 / s) or at approximately 5, 10, 20, 25, 50, 100, 200 or 250 rpm (revolutions per minute).

[0076] Aqueous liquids that can be absorbed by the aerogel described herein can be at temperatures, for example, from about 3°C ​​to about 80°C (e.g., 20°C, 25°C, 30°C, 35°C, 37°C, 40°C, 45°C, 4°C-30°C, 15°C-30°C, 15°C-25°C, 30°C-45°C, 30°C-40°C, 35°C-45°C, or 35°C-40°C).

[0077] Aqueous liquids that can be absorbed by the aerogel described herein can be, for example, bodily fluids, urine, blood, serum, menstrual fluid, liquid feces (e.g., diarrhea), bile, gastric acid / gastric juice, vomit, amniotic fluid, breast milk, cerebrospinal fluid, exudate, lymph, mucus (e.g., nasal mucus, sputum), peritoneal fluid, pleural fluid, pus, rheum, saliva, sputum, synovial fluid, sweat, tears, water, or saline solution.

[0078] The absorption of aqueous liquids described herein can be determined, for example, by measuring the water retention value (WRV) of the aerogel (or other similar terms such as water retention capacity or water absorption). The WRV described herein can be measured by any suitable means, such as by the method disclosed in U.S. Patent Application Publication No. 2016 / 0175811 (e.g., Example 7 therein, which is incorporated herein by reference), or by any of the methods disclosed in the examples below. In short, the WRV of a material (such as an aerogel) described herein can be calculated using the following formula: ((mass of wet material - mass of dry material) / mass of dry material) 100. For example, WRV can be measured with respect to any aqueous liquid as disclosed herein. Therefore, although the term WRV (and similar terms) contains the word “water”, it should be understood that WRV can be measured with respect to any type of aqueous liquid (such as aqueous solutions or bodily fluids) disclosed herein. For example, the absorption of the aerogel of this invention to an aqueous liquid can optionally be determined by measuring the centrifugation retention capacity (CRC), as disclosed in the examples below or in U.S. Patent No. 8,859,758 (which is incorporated herein by reference). The absorption in this invention can optionally be measured by determining the absorption under load (AUL), as via the method disclosed in U.S. Patent No. 8,859,758 or the EDANA (European Association for Disposable and Nonwoven Products) standard test WSP 242.2.R3 (12) (both of which are incorporated herein by reference), or as disclosed in the examples below. The load applied in this document may be, for example, a pressure above atmospheric pressure (i.e., above about 15 psi), and / or may be about or at least about 50, 75, 100, 125, 150, 200, 250, 500, 1000, 2500, 5000, 75-150, or 75-125 g (e.g., as applied at about or below about 2, 4, 6, 8, 10, or 12 cm). 2 (Pressure / weight of aerogel area).

[0079] The aerogels described herein may have, for example, a value of about or at least about 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 1000-2500, 1200-2500, 1300-2500, 1400-2500, 150 WRV values ​​of 0-2500, 1800-2500, 1000-2200, 1200-2200, 1300-2200, 1400-2200, 1500-2200, 1800-2200, 1000-2000, 1200-2000, 1300-2000, 1400-2000, 1500-2000, or 1800-2000. Any of these values ​​can be used to measure WRV with or without applied load (e.g., as above). For example, any of the aforementioned WRV values ​​can be for aerogels that have been exposed (with or without an applied load) to an aqueous liquid for about or at least about 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 60-120, 60-110, 60-100, 80-120, 80-110, or 80-100 seconds (i.e., absorption time).

[0080] Compositions / products comprising aerogels as disclosed in this invention may be in the form of, or contained therein, personal care products, home care products (household goods), medical products, pharmaceutical products, or industrial products. In some aspects, the compositions / products herein (e.g., any of the foregoing) may be absorbent or superabsorbent products. In some aspects, personal care products, home care products, medical products, pharmaceutical products, or industrial products are optionally at least partially designed for handling the absorption of aqueous liquids.

[0081] Examples of personal care products and / or their use in the absorption of aqueous liquids include absorbent personal hygiene products such as baby diapers, toilet training pants / pads, incontinence products (e.g., pads, adult diapers) and feminine hygiene products (e.g., sanitary napkins / pads, tampons, interval products, panty liners). Thus, in some aspects, personal care products can be described as absorbent articles of personal care that can be placed close to or near the skin to absorb and contain fluids excreted or flowing from the body. Examples of personal care products that can be adapted accordingly to utilize the absorbency of the aerogel material described herein (e.g., as a replacement or supplement to the absorbent material originally used in the product) are disclosed in the following: WO U.S. Patent Application Publications 1999 / 037261, 2004 / 0167491, 2009 / 0204091, 2001 / 0014797, 2013 / 0281949, 2002 / 0087138, 2010 / 0241098, 2011 / 0137277 and 2007 / 0287971, and U.S. Patents 4,623,339, 2,627,858, and 35 All of these patent applications and patent publications are incorporated herein by reference: 85998, 3964486, 6579273, 6183456, 5820619, 4846824, 4397644, 4079739, 8987543, 4781713, 5462539, 8912383, 3749094, 3322123, 4762521, and 5342343.

[0082] Examples of industrial products and / or their use in the absorption of aqueous liquids include cable packaging (e.g., packaging for power or communication cables); food pads (e.g., meat pads); agricultural and forestry applications such as retaining water in soil and / or releasing water to plant roots; fire-fighting devices; and the removal of spills from acidic or alkaline aqueous solutions. Examples of industrial products that can be adapted accordingly to utilize the absorbency of the aerogel materials described herein are disclosed in the following: U.S. Patent Application Publications Nos. 2002 / 0147483, 2006 / 0172048, 20050008737, 2008 / 0199577, 2012 / 0328723 and 2004 / 0074271, and U.S. Patent Nos. 5906952, 7567739, 5176930, 6695138, 4865855, 7459501, 5456733, 9089730, 5849210, 7670513, 7670513, 5683813, 5342543, 4840734 and 4894179, all of which are incorporated herein by reference.

[0083] Examples of medical products and / or their use in the absorption of aqueous liquids include wound healing dressings such as bandages and surgical pads; hospital bedding; sanitary towels / pads; controlled drug release devices; cell immobilization islands; three-dimensional cell culture media; bioactive scaffolds for regenerative medicine; gastric expansion devices; and the disposal of controlled drugs. Examples of medical products that can be adapted accordingly to utilize the absorbency of the aerogel materials described herein are disclosed in the following: WO 1998 / 046159, U.S. Patent Application Publication Nos. 2005 / 0256486, 20030070232, and 20040128764, and U.S. Patent Nos. 6,191,341, 7,732,657, 4,925,453, 9,161,860, 3,187,747, and 5,701,617, all of which are incorporated herein by reference.

[0084] This invention discloses an absorption method comprising at least contacting a composition / product containing an aerogel herein with a composition containing an aqueous liquid, wherein the composition / product absorbs the aqueous liquid from the composition containing the liquid. For example, the composition containing the aqueous liquid can be any aqueous liquid disclosed herein. Therefore, in some aspects, the aerogel may further contain water or an aqueous liquid (e.g., as disclosed herein); typically, the water or aqueous liquid has already been absorbed by the aerogel. For example, the aerogel that has absorbed water may be under load or unloaded. For example, the amount of water or aqueous liquid contained in the aerogel herein can be up to an amount (or range) reflecting the water absorption capacity of the aerogel (e.g., as disclosed herein).

[0085] Some aspects of this disclosure relate to a caustic alkali solution (aqueous caustic alkali solution) comprising at least (i) an aqueous caustic alkali solvent, (ii) a water-insoluble α-glucan and (iii) a metal hydroxide, wherein at least about 50% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 glycosidic bonds, wherein the water-insoluble α-glucan is soluble in the aqueous caustic alkali solvent and the metal hydroxide is insoluble (i.e., not insoluble in) the aqueous caustic alkali solvent, and wherein the metal hydroxide is calcium hydroxide [Ca(OH)2], magnesium hydroxide [Mg(OH)2] or titanium hydroxide [Ti(OH)4] (or any other hydroxide of an alkaline earth metal or transition metal suitable for producing a hydrogel of α-1,3-glucan using the aqueous caustic alkali solution described herein). The water-insoluble α-glucan component of the caustic alkali solution described herein may be as disclosed in this invention; for example, it may have the molecular weight (e.g., DP, DPw, or DPn) and / or glycosidic bond spectrum as disclosed herein for water-insoluble α-glucans.

[0086] In some aspects, the metal hydroxide may be calcium hydroxide [Ca(OH)2], magnesium hydroxide [Mg(OH)2], or titanium hydroxide [Ti(OH)4]. The metal hydroxides described herein are contemplated to be, for example, another type of alkaline earth metal hydroxide or transition metal hydroxide suitable for forming hydrogels using the aqueous caustic alkali solutions described herein. Typically, the aqueous caustic alkali solutions or hydrogels described herein have one metal hydroxide, but in some cases, they may have two or more metal hydroxides [e.g., Ca(OH)2 and Mg(OH)2, Ca(OH)2 and Ti(OH)4, Mg(OH)2 and Ti(OH)4]. The metal hydroxides described herein, as contained in the aqueous caustic alkali solutions, are typically insoluble in (i.e., insoluble in) caustic alkali solvents; therefore, the aqueous caustic alkali solutions described herein may also optionally be described as “aqueous caustic alkali liquid compositions” or other similar terms.

[0087] Insoluble metal hydroxides in aqueous caustic alkali solutions can be provided therein by adding the corresponding salts (salt precursors of the metal hydroxides) to the caustic alkali solutions of this disclosure. For example, MgCl₂·6H₂O, CaCl₂·2H₂O, or Ti[OCH(CH₃)₂]₄ inorganic salts can be added to provide insoluble Mg(OH)₂, Ca(OH)₂, or Ti(OH)₄; these hydroxides precipitate (become insoluble) in consideration of the increase in pH of the solution. For example, the salts to be added to the aqueous caustic alkali solution can be provided as an aqueous solution of the salt. In some aspects, insoluble metal hydroxides can be provided therein prior to the introduction of insoluble α-glucan into the aqueous caustic alkali solutions of this disclosure.

[0088] The aqueous caustic alkali solution or hydrogel described herein may contain a sufficient amount of metal hydroxide to provide an aerogel containing a given amount of the corresponding metal oxide (e.g., as disclosed herein) after water is removed from the hydrogel (in the formation of an aerogel). In some aspects, the balance of the aqueous caustic alkali solution or hydrogel by mass is (i) water-insoluble α-glucan and (ii) water or an aqueous solution (i.e., such an aqueous caustic alkali solution or hydrogel may be described as consisting of a metal hydroxide, a water-insoluble α-glucan, and an aqueous / water solution) (when referring to an aqueous caustic alkali solution, it typically further contains an alkaline hydroxide [e.g., an alkali metal hydroxide such as NaOH, KOH, or LiOH]). However, in some aspects, the aqueous caustic alkali solution or hydrogel may contain one or more other components. In some aspects, the aqueous caustic alkali solution or hydrogel may contain about 3, 5, 6, 7, 8, 9, 10, 12, 14, 3-9, 4-8, or 5-7 wt% water-insoluble α-glucan. In some aspects, the aqueous caustic alkali solution or hydrogel does not contain polyurethane or any other organic polymer (other than the insoluble α-glucan), and / or does not contain silica. It should be noted that the aforementioned disclosed aqueous caustic alkali solution may be an aqueous caustic alkali solution provided when performing the methods for generating aerogels or hydrogels described herein.

[0089] The aqueous caustic solvents described herein are typically capable of dissolving aqueous insoluble α-glucans as disclosed herein. For example, the aqueous caustic solvent may comprise a basic hydroxide. The basic hydroxide may comprise at least one metal hydroxide (e.g., NaOH, KOH, LiOH) or an organic hydroxide (e.g., tetraethylammonium hydroxide). The aqueous caustic solvent may be as disclosed in, for example, International Patent Application Publications WO 2015 / 200612 or WO 2015 / 200590, or U.S. Patent Application Publications 2017 / 0208823 or 2017 / 0204203 (each of which is incorporated herein by reference), or as disclosed in the following examples.

[0090] In some aspects, the aqueous caustic solvent comprises one or more basic hydroxides dissolved in water. The concentration of the one or more basic hydroxides may be, for example, about or at least about 2.5, 2.6, 2.7, 2.75, 2.8, 2.9, 3, 4, 5, 6, 7, 2.5-4, 2.5-3, 2.5-2.8, 2.6-4, 2.6-3, 2.6-2.8, 2.7-4, 2.7-3, 2.7-2.8, 3-5, or 3-4 wt%.

[0091] The pH of the aqueous caustic alkali solution and / or its aqueous caustic alkali solvent in this document may be, for example, about or at least about 11.0, 11.5, 12.0, 12.5, 12.75, 13.0, 13.25, 13.5, 13.75, 12.0-13.5, 12.0-13.0, 12.5-13.75, 12.5-13.5, 12.5-13.25, 12.5-13.0, 12.75-13.75, 12.75-13.5, 12.75-13.25, 12.75-13.0, 13.0-13.75, 13.0-13.5, 13.0-13.25, 13.25-13.75, or 13.25-13.5. In some respects, this pH can characterize an aqueous caustic alkali solution before the addition of acid. However, in other respects, this pH can characterize an aqueous caustic alkali solution after the addition of acid (e.g., for partial neutralization, where the pH decreases to be closer to neutral, but not completely neutral). The temperature of the aqueous caustic alkali solution as described herein can be, for example, about or at least about 1°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 1°C-50°C, 1°C-45°C, 1°C-40°C, 1°C-35°C, 1°C-30°C, 1°C-25°C, 1°C-20°C, 15°C-50°C, 15°C. -45°C, 15°C-40°C, 15°C-35°C, 15°C-30°C, 15°C-25°C, 15°C-20°C, 20°C-50°C, 20°C-45°C, 2 0°C-40°C, 20°C-35°C, 20°C-30°C, 20°C-25°C, 5°C-30°C, 10°C-30°C, 5°C-25°C or 10°C-25°C.

[0092] Some aspects of this disclosure relate to a method for producing hydrogels or aerogels as disclosed herein. Such a method may include at least:

[0093] (a) Provide an aqueous caustic alkali solution as disclosed herein.

[0094] (b) To convert the aqueous caustic alkali solution into the desired form.

[0095] (c) Chemically or ionically modifying an aqueous caustic alkali solvent (chemically or ionically modified caustic alkali solution) such that the water-insoluble α-glucan and metal hydroxide are insoluble (i.e., insoluble in) the solvent, thereby producing a hydrogel, and, if an aerogel is prepared,

[0096] (d) Remove all or most of the water from the hydrogel, thereby producing an aerogel.

[0097] The aerogels or hydrogels mentioned herein may be produced, for example, by aerogel / hydrogel generation method as disclosed in this invention.

[0098] Step (a) of the aerogel / hydrogel generation method is typically carried out by providing an aqueous caustic alkali solution as disclosed in this invention. Step (a) may include, for example, combining (mixing, introducing) a suitable salt (e.g., MgCl2·6H2O, CaCl2·2H2O, or Ti[OCH(CH3)2]4) (a salt precursor of the metal hydroxide) with an aqueous caustic alkali solution in which a water-insoluble α-glucan is dissolved, typically wherein the salt is provided in a form dissolved in an aqueous solution, and the metal hydroxide precipitates from the solution when combined with the aqueous caustic alkali solution. Alternatively, in some aspects, the salt may be added to the aqueous caustic alkali solution before the α-glucan is added to the solution. Typically, the metal hydroxide precipitates (becomes insoluble) when its corresponding salt is mixed into the aqueous caustic alkali solution at an elevated pH. The amount of salt provided may be, for example, the amount of metal hydroxide content disclosed elsewhere herein.

[0099] Step (b) of the aerogel / hydrogel generation method described herein (i.e., transforming the aqueous caustic alkali solution into a desired form) may include, for example, placing / pouring the aqueous caustic alkali solution from step (a) into a form having the desired shape of the aerogel / hydrogel product. This shape may be a cube, cubic, spherical, cylindrical prism (e.g., a triangular or polygonal prism), pyramid (e.g., a pyramid based on a square, triangle, or polygon), conical, or any other three-dimensional shape. In some aspects, step (b) may include placing / pouring the aqueous caustic alkali solution from step (a) into a film, coating, layer, or sheet; this form may have a thickness of, for example, about or at least about 1 μm, 5 μm, 10 μm, 50 μm, 100 μm, 500 μm, 1 mm, 5 mm, 1 cm, 5 cm, or 10 cm. The aerogel or hydrogel product described herein may be, for example, any of the aforementioned shapes. Alternatively, the aerogel or hydrogel shape may be a shape cut from a larger aerogel or hydrogel. Although step (b) may be performed before step (c) of the aerogel / hydrogel generation method herein, step (b) may optionally be performed at approximately the same time as step (c) or shortly after its start but before hydrogel formation (see disclosure below).

[0100] Step (c) of the aerogel / hydrogel generation method described herein may include chemically or ionicly modifying the aqueous caustic solvent (chemically or ionically modified aqueous caustic solution) such that the water-insoluble α-glucan and metal hydroxide are insoluble in the solvent (i.e., insoluble in the solvent) (i.e., the α-glucan precipitates from the solution; the metal hydroxide has precipitated from the solution according to step [a]), thereby generating a hydrogel. This can be carried out, for example, by a coagulation process and / or a neutralization process or a partial neutralization process; step (c) typically includes lowering the pH of the aqueous caustic solution to a pH that makes the water-insoluble α-glucan insoluble in the solvent. Typically, step (c) is used to allow the form / shape generated in step (b) to be self-supporting. In some aspects, step (c) may be carried out by mixing one or more acids, such as weak acids (e.g., acetic acid, citric acid) or strong acids (e.g., sulfuric acid), into the aqueous caustic solution. In some respects, the amount of acid added will result in an acid concentration of approximately 0.008, 0.010, 0.012, 0.0125, 0.013, 0.014, 0.015, 0.020, 0.025, 0.030, 0.040, 0.050, 0.075, 0.10, 0.25, 0.50, 1, 2.5, 5, 0.008-0.020, 0.008-0.015, 0.010-0.020, 0.010-0.015, or 0.01-0.014 wt% (where such wt% will occur if no acid is consumed during subsequent neutralization). The pH resulting from neutralization (such as partial neutralization) can be any of those pH values / ranges listed above for aqueous caustic alkali solutions, for example. In some respects, such as in partial neutralization, the pH decrease does not exceed 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5. The temperature at which step (c) is performed can be any of the temperatures listed above for aqueous caustic alkali solutions, for example. The time elapsed for neutralization or partial neutralization (e.g., from the addition of the neutralizing agent, such as an acid, until hydrogel formation) can be, for example, about or at least about 2, 3, 6, 12, 24, 36, 48, 60, 72, 84, or 96 hours. Typically, after the neutralizing agent has been thoroughly mixed with the solution, the solution remains stationary during hydrogel formation (e.g., no agitation [intentionally or unintentionally], such as orbital rotation, is applied to the solution). As disclosed above, step (b) can optionally be performed simultaneously with step (c) or shortly after its initiation but before hydrogel formation. For example, a solution can be placed into the desired form within a short period of time (e.g., about 1, 2, 5, 10, 15, or 20 minutes) after a neutralizing agent (such as an acid) has been mixed into it.In some respects, the solidification and / or neutralization in step (c) may be performed as described in U.S. Patent Application Publication Nos. 2016 / 0177471, 2016 / 0333157, 2017 / 0283568 or 2015 / 0191550 or U.S. Patent Nos. 7,000,000 or 1,1098,334 (which are incorporated herein by reference) or as disclosed in the following examples (e.g., where each condition / parameter is performed within 5%, 10%, or 15% of the relevant condition / parameter disclosed in the examples).

[0101] Typically, the hydrogel formed in step (c) can be separated. For example, the hydrogel can be washed with water or a suitable polar organic solvent (e.g., alcohols such as ethanol) (with or without added water). If desired, washing can be performed until the (washing solution) reaches a neutral pH (e.g., pH 6-8, or about 7). The washing or post-washing step may optionally further include immersing the hydrogel in a 1-10 wt% (e.g., about 5 wt%) plasticizer (e.g., glycerol or ethylene glycol) solution (e.g., based on water or alcohol) for a suitable period of time (e.g., at least 2, 3, or 4 minutes). The hydrogel may optionally be stored in water or a suitable polar organic solvent solution (e.g., alcohols such as ethanol) (with or without added water). Although a “hydrogel” containing a liquid without water as defined above is not technically a hydrogel, for ease of reference, such a composition is referred to herein as a “hydrogel.”

[0102] If an aerogel (obtained using the hydrogel product of step [c]) is desired, step (d) of the aforementioned generation method can be performed. Step (d) may include removing all or most (e.g., at least 97 wt%, 98 wt%, 99 wt%, 99.5 wt%, or 99.9 wt%) of the resident liquid (typically water and / or any other suitable liquid, such as a polar organic solvent, with or without water) from the hydrogel, thereby generating the aerogel. Removal of the resident liquid from the hydrogel can be carried out, for example, in a manner in which the structure of the hydrogel remains substantially unchanged / altered. For example, the resident liquid can be removed in a manner that substantially preserves the nano- and / or micro-structures of the hydrogel (structures observed at the nano or micro scale, respectively) as they existed prior to the removal of the resident liquid. In some aspects, substantial preservation of the hydrogel structure can be related to the average pore size. For example, the average pore diameter of an aerogel from which the stagnant liquid has been removed can be within (±) about 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1% of the average pore diameter that already existed before the stagnant liquid was removed (i.e., when it is a hydrogel). For example, the average pore diameter can be measured as disclosed herein.

[0103] Freeze-drying (lyophilization) and supercritical drying are examples of methods used herein for removing resident liquids from hydrogels to produce aerogels. Standard air-drying methods (such as oven drying) are typically not used herein for removing resident liquids from hydrogels. For example, freeze-drying as described herein can be performed following the procedures listed in the disclosed examples. In some aspects, freeze-drying can be performed under an applied vacuum at temperatures of about 120°C, 110°C, 105°C, 100°C, 90°C, 80°C, 70°C, 60°C, 50°C, 40°C, 80°C to 120°C, 80°C to 110°C, 90°C to 120°C, 90°C to 110°C, or 100°C to 110°C and / or for about or at least about 1, 2, 6, 12, 24, 36, 48, 60, 72, or 84 hours. A vacuum can be applied such that the pressure is, for example, less than about 400, 300, 200, 100, or 50 millitors; in some aspects, the vacuum pressure can be about 150-250, 175-225, or about 200 millitors. In some aspects, the hydrogel can be normally frozen (e.g., at about 20°C at atmospheric pressure) before entering the freeze-drying process. Supercritical drying can be carried out, for example, using supercritical CO2 (supercritical CO2 drying), as disclosed in International Patent Application Publication No. WO 2019 / 167013 or U.S. Patent Application Publication Nos. 2016 / 0058045, 2016 / 0068650, or 20130018112 (which are incorporated herein by reference).

[0104] Compositions / products comprising aerogels or hydrogels as disclosed in this invention may be in the form of, for example, home care products, personal care products, industrial products, medical products, or pharmaceutical products, as described in any of the following: U.S. Patent Application Publication Nos. 2018 / 0022834, 2018 / 0237816, 2018 / 0230241, 20180079832, 2016 / 0311935, 2016 / 0304629, 2015 / 0232785, 2015 / 0368594, 2015 / 0368595, 2016 / 0122445, 2019 / 0202942, or 2019 / 0309096, or International Patent Application Publication No. WO 2016 / 133734, all of which are incorporated herein by reference. In some respects, compositions / products comprising the aerogels or hydrogels described herein may contain at least one component / ingredient of any of the home care products, personal care products, industrial products, medical products, or pharmaceutical products disclosed in the foregoing disclosures and / or the present invention.

[0105] Non-limiting examples of the compositions and methods disclosed herein include:

[0106] 1. A composition (product) comprising at least an aerogel (or foam / solid foam, or sponge / solid sponge), wherein the aerogel comprises at least a water-insoluble α-glucan and a metal oxide, wherein at least about 50% of the glycosidic bonds of the insoluble α-glucan are α-1,3 bonds, and wherein the metal oxide is calcium oxide (CaO), magnesium oxide (MgO), or titanium dioxide (TiO2) (or any other suitable oxide of an alkaline earth metal or transition metal).

[0107] 2. The composition as described in Example 1, wherein at least about 90% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 glycosidic bonds.

[0108] 3. The composition as described in Example 1 or 2, wherein the water-insoluble α-glucan has a weight-average degree of polymerization (DPw) of at least about 10.

[0109] 4. The composition as described in Examples 1, 2 or 3, wherein the DPw is at least about 400.

[0110] 5. The composition as described in Examples 1, 2, 3 or 4, wherein the metal oxide is titanium dioxide (TiO2).

[0111] 6. The composition as described in Examples 1, 2, 3, 4 or 5, wherein the aerogel contains less than about 20 wt% (or less than about 10 wt% or 8 wt%) of the metal oxide, optionally wherein the balance by mass of the aerogel is the water-insoluble α-glucan.

[0112] 7. The composition as described in Examples 1, 2, 3, 4, 5 or 6, wherein the metal oxide interacts with the water-insoluble α-glucan via hydrogen bonding.

[0113] 8. The composition as described in Examples 1, 2, 3, 4, 5, 6 or 7, wherein the aerogel has been pulverized (e.g., pulverized into particles, such as powder) (i.e., micronized).

[0114] 9. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7 or 8, wherein the aerogel further comprises water or an aqueous liquid, typically wherein the water or aqueous liquid is absorbed by the aerogel, and optionally wherein the aerogel is under a load.

[0115] 10. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the composition is a personal care product, home care product, medical product, pharmaceutical product or industrial product, and / or the composition is an absorbent product (e.g., a personal care product, home care product, medical product, pharmaceutical product or industrial product that can absorb aqueous liquids).

[0116] 10a. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein the aerogel is produced by the method described in Examples 15, 16, 17, 18 or 19.

[0117] 11. A caustic alkali solution (aqueous caustic alkali solution) comprising at least (i) an aqueous caustic alkali solvent, (ii) a water-insoluble α-glucan and (iii) a metal hydroxide, wherein at least about 50% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 glycosidic bonds, wherein the water-insoluble α-glucan is soluble in the aqueous caustic alkali solvent and the metal hydroxide is insoluble in the aqueous caustic alkali solvent, and wherein the metal hydroxide is calcium hydroxide, magnesium hydroxide or titanium hydroxide (or hydroxide of any other alkaline earth metal or transition metal, wherein such hydroxide is insoluble in the aqueous caustic alkali solvent).

[0118] 12. The caustic alkali solution as described in Example 11, wherein at least about 90% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 glycosidic bonds.

[0119] 13. A caustic alkali solution as described in Example 11 or 12, wherein the water-insoluble α-glucan has a weight-average degree of polymerization (DPw) of at least about 10 (or at least about 400).

[0120] 14. The caustic alkali solution as described in Examples 11, 12 or 13, wherein the aqueous caustic alkali solvent contains at least one basic hydroxide (e.g., an alkali metal hydroxide, such as NaOH, KOH or LiOH).

[0121] 15. A method / process for producing an aerogel (e.g., according to Examples 1, 2, 3, 4, 5, 6, 7, 8, or 9), the method comprising: (a) providing a caustic alkali solution (aqueous caustic alkali solution) as described in Examples 11, 12, 13, or 14; (b) converting the caustic alkali solution into a desired form; (c) chemically or ionicly modifying the aqueous caustic alkali solvent (chemically or ionicly modifying the caustic alkali solution) such that the water-insoluble α-glucan and the metal hydroxide are insoluble (i.e., insoluble in) the solvent, thereby producing a hydrogel (optionally, step [c] may be performed before or concurrently with step [b]); and (d) removing all or most of the water (e.g., at least 98 wt%, 99 wt%, 99.5 wt%, or 99.9 wt% water) from the hydrogel, thereby producing an aerogel.

[0122] 16. The method as described in Example 15, wherein step (a) comprises combining (mixing, introducing) a salt of the metal hydroxide (a salt precursor of the metal hydroxide) with an aqueous caustic alkali solution in which the water-insoluble α-glucan is dissolved, typically wherein the salt is provided in the form of a solution dissolved in an aqueous solution, and the metal hydroxide precipitates from the solution when combined with the aqueous caustic alkali solution.

[0123] 17. The method as described in Example 15 or 16, wherein step (c) comprises lowering the pH of the caustic alkali solution to a pH at which the water-insoluble α-glucan is insoluble in the solvent (e.g., neutralizing or partially neutralizing the solution, as can be done by adding an acid) (in some respects, the pH reduction is allowed to occur for at least about 48 hours) (in some respects, the pH reduction is not more than 0.5).

[0124] 18. The method as described in Examples 15, 16 or 17, wherein step (c) further includes keeping the solution still during the formation of the hydrogel (e.g., without applying any liquid agitation means).

[0125] 19. The method as described in Examples 15, 16, 17 or 18, wherein step (d) comprises freeze-drying or supercritical drying the hydrogel (or any other process that removes the residual water / liquid in a manner that substantially preserves the nanostructure and / or microstructure of the hydrogel as it existed prior to the removal of the residual water / liquid) to form the aerogel.

[0126] 20. An absorption method comprising contacting a composition / product as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 10a with a composition comprising an aqueous liquid, wherein the composition / product absorbs the aqueous liquid from the composition comprising the aqueous liquid.

[0127] Non-limiting examples of the compositions and methods disclosed herein include:

[0128] 1b. A composition (product) comprising at least a hydrogel, wherein the hydrogel comprises at least a water-insoluble α-glucan and a metal hydroxide, wherein at least about 50% of the glycosidic bonds of the insoluble α-glucan are α-1,3 bonds, and wherein the metal hydroxide is calcium hydroxide [Ca(OH)2], magnesium hydroxide [Mg(OH)2], or titanium hydroxide [Ti(OH)4] (or a hydroxide of any other alkaline earth metal or transition metal, wherein the metal hydroxide is suitable for forming the hydrogel of the water-insoluble α-glucan).

[0129] 2b. The composition as described in Example 1b, wherein at least about 90% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 glycosidic bonds.

[0130] 3b. The composition as described in Example 1b or 2b, wherein the water-insoluble α-glucan has a weight-average degree of polymerization (DPw) of at least about 10.

[0131] 4b. The composition as described in Examples 1b, 2b or 3b, wherein the DPw is at least about 400.

[0132] 5b. The composition as described in Examples 1b, 2b, 3b or 4b, wherein the metal hydroxide is the titanium hydroxide.

[0133] 6b. The composition as described in Examples 1b, 2b, 3b, 4b or 5b, wherein the hydrogel contains less than about 20 wt% (dry solids basis [dsb]) (or less than about 15 wt% dsb or 10 wt% dsb), optionally wherein the balance of the mass of the hydrogel based on dry solids is the water-insoluble α-glucan.

[0134] 7b-1. The composition as described in Examples 1b, 2b, 3b, 4b, 5b or 6b, wherein the composition is a personal care product, a home care product, a medical product, a pharmaceutical product or an industrial product.

[0135] 7b-2. The composition as described in Examples 1b, 2b, 3b, 4b, 5b, 6b or 7b, wherein the hydrogel is produced by the method described in Examples 12b, 13b, 14b or 15b.

[0136] 8b. A caustic alkali solution (aqueous caustic alkali solution) comprising at least (i) an aqueous caustic alkali solvent, (ii) a water-insoluble α-glucan and (iii) a metal hydroxide, wherein at least about 50% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 glycosidic bonds, wherein the water-insoluble α-glucan is soluble in the aqueous caustic alkali solvent and the metal hydroxide is insoluble in the aqueous caustic alkali solvent, and wherein the metal hydroxide is calcium hydroxide, magnesium hydroxide or titanium hydroxide (or hydroxide of any other alkaline earth metal or transition metal, wherein such hydroxide is insoluble in the aqueous caustic alkali solvent).

[0137] 9b. A caustic alkaline solution as described in Example 8b, wherein at least about 90% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 glycosidic bonds.

[0138] 10b. A caustic alkali solution as described in Example 8b or 9b, wherein the water-insoluble α-glucan has a weight-average degree of polymerization (DPw) of at least about 10 (or at least about 400).

[0139] 11b. A caustic alkali solution as described in Examples 8b, 9b or 10b, wherein the aqueous caustic alkali solvent comprises at least one basic hydroxide (e.g., an alkali metal hydroxide, such as NaOH, KOH or LiOH).

[0140] 12b. A method / process for producing a hydrogel (e.g., according to Examples 1b, 2b, 3b, 4b, 5b, 6b, or 7b), the method comprising: (a) providing a caustic alkali solution (aqueous caustic alkali solution) as described in Examples 8b, 9b, 10b, or 11b; (b) converting the caustic alkali solution into a desired form; and (c) chemically or ionicly modifying the aqueous caustic alkali solvent (chemically or ionicly modifying the caustic alkali solution) such that the water-insoluble α-glucan and the metal hydroxide are insoluble in (i.e., insoluble in) the solvent, thereby producing a hydrogel (optionally, step [c] may be performed before or concurrently with step [b].

[0141] 13b. The method as described in Example 12b, wherein step (a) comprises combining (mixing, introducing) a salt of the metal hydroxide (a salt precursor of the metal hydroxide) with an aqueous caustic alkali solution in which the water-insoluble α-glucan is dissolved, typically wherein the salt is provided in a form dissolved in an aqueous solution, and the metal hydroxide precipitates from the solution when combined with the aqueous caustic alkali solution.

[0142] 14b. The method as described in Examples 12b or 13b, wherein step (c) comprises lowering the pH of the caustic alkali solution to a pH at which the water-insoluble α-glucan is insoluble in the solvent (e.g., neutralizing or partially neutralizing the solution, as can be done by adding an acid) (in some respects, the pH reduction is allowed to occur for at least about 48 hours) (in some respects, the pH reduction does not exceed 0.5).

[0143] 15b. The method as described in Examples 12b, 13b or 14b, wherein step (c) further includes keeping the solution still during the formation of the hydrogel (e.g., without applying any liquid agitation means).

[0144] In some alternative / auxiliary aspects, non-limiting examples of compositions include:

[0145] 1. A composition (product) comprising about 35 to 65 wt% polyurethane, about 1 to 15 wt% water-insoluble α-glucan, and about 30 to 60 wt% propylene glycol, wherein at least about 50% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 bonds, and typically wherein the composition is a dry solid material (the water-insoluble α-glucan may be as disclosed herein).

[0146] 2. The composition as described in Example 1, wherein the composition is an elastomer composition.

[0147] 3. The composition as described in Example 1 or 2, wherein the composition is a foam.

[0148] 4. The composition as described in Examples 1, 2 or 3, wherein the composition is a molded composition / article (or coating or film).

[0149] 5. The composition as described in Examples 1, 2, 3 or 4, wherein at least about 90% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 bonds.

[0150] 6. The composition as described in Example 5, wherein about 100% of the glycosidic bonds of the water-insoluble α-glucan are α-1,3 bonds.

[0151] 7. The composition as described in Examples 1, 2, 3, 4, 5 or 6, wherein the weight-average degree of polymerization (DPw) of the water-insoluble α-glucan is about or at least about 400.

[0152] 8. The composition as described in Example 7, wherein the DPw of the water-insoluble α-glucan is about or at least about 700 or 800.

[0153] 9. The composition as described in Example 8, wherein the DPw of the water-insoluble α-glucan is about or at least about 1400 or 1600.

[0154] 10. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the composition comprises about 3 to 7 wt%, 4 to 6 wt% or 5 wt% of the water-insoluble α-glucan.

[0155] 11. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein the composition comprises about 40 to 50 wt%, 42.5 to 47.5 wt%, or 45 wt% of the propylene glycol.

[0156] 12. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, wherein the composition comprises about 40 to 60 wt%, 45 to 55 wt% or 50 wt% of the polyurethane.

[0157] 13. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, wherein the composition comprises about 40 to 60 wt% (e.g., about 50 wt%) of the polyurethane, about 40 to 50 wt% (e.g., about 45 wt%) of the propylene glycol and about 3 to 7 wt% (e.g., about 5 wt%) of the water-insoluble α-glucan.

[0158] 14. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, wherein the polyurethane is the product of the reaction of a polyol with a diisocyanate, optionally wherein about three parts of the polyol are reacted with about two parts of the diisocyanate in a ratio-wise manner to produce the polyurethane.

[0159] 15. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, wherein the polyurethane is any polyurethane as disclosed in U.S. Patent Application Publication No. 2019 / 0225737, which is incorporated herein by reference.

[0160] 16. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15, wherein the composition comprises at least one additive (e.g., pigments and / or abrasives) (e.g., any suitable additive disclosed in International Patent Application Publication Nos. WO2022 / 235655 or WO 2023 / 183280, each of which is incorporated herein by reference).

[0161] 17. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16, wherein the composition is a consumer product or a commercial / industrial product.

[0162] 18. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17, wherein the composition is footwear (e.g., a shoe or athletic shoe) or a component thereof (e.g., an insole).

[0163] 19. The composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17, wherein the composition is bedding, furniture, automotive interiors, carpet padding or packaging, or any other product / article that typically contains polyurethane and / or polyurethane foam.

[0164] 20. A composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19, wherein the composition has a lower compression set (e.g., about 25%, 30%, 40%, 50%, 60%, 70% or 80% lower) than a control composition lacking the water-insoluble α-glucan (e.g., replaced by an equivalent amount of propylene glycol by wt%) (e.g., the compression set may be about 8% to 20% or about 8% to 15%, as measured using suitable techniques such as according to ASTM D395 (which is incorporated herein by reference).

[0165] 21. A composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, wherein the composition has a higher tear strength (e.g., about or at least about 100%, 200%, 300% or 400% higher) than a control composition lacking the water-insoluble α-glucan (e.g., replaced by an equivalent amount of propylene glycol by wt%) (e.g., the tear strength may be about 3 to 7 or about 4 to 6, as measured using suitable techniques such as according to ASTM D624 (which is incorporated herein by reference).

[0166] 22. A composition as described in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or 21, wherein the composition has a higher tensile strength (e.g., about 10%, 20%, 30%, 40% or 50% higher) than a control composition lacking the water-insoluble α-glucan (e.g., replaced by an equivalent amount of propylene glycol by wt%) (e.g., the tensile strength may be about 10-14 or about 10-12, as measured using a suitable technique such as according to ASTM D638 (which is incorporated herein by reference). Example

[0167] This disclosure is further illustrated in the following examples. It should be understood that although these examples indicate certain aspects herein, they are given by way of illustration only. From the foregoing discussion and these examples, those skilled in the art can determine the essential features of the disclosed embodiments, and various changes and modifications can be made to adapt the disclosed embodiments to a variety of uses and conditions without departing from the spirit and scope of the disclosed embodiments.

[0168] Materials and Methods

[0169] Reagents:Calcium chloride dihydrate (CaCl2.2H2O, 99%, Fisher Chemical), sodium hydroxide (NaOH, 99%, EM Science), magnesium chloride hexahydrate (MgCl2.6H2O, 99%, Sigma-Aldrich), titanium isopropoxide (Ti[OCH(CH3)2]4, 99%, Sigma-Aldrich), acetic acid (99%, Sigma-Aldrich), sodium hydroxide (NaOH, 99%, EM Science), and anhydrous ethanol (78%, Sigma-Aldrich) were obtained from their respective suppliers and were used for their respective solution preparations without further processing. Deionized water collected from the Milli-DI® water purification system was used throughout this work.

[0170] Representative preparation of α-1,3-glucan: α-1,3-glucan having approximately 100% α-1,3 glycosidic bonds can be synthesized, for example, by following the procedure disclosed in U.S. Application Publication No. 2014 / 0179913 (see, for example, Example 12 therein), which is incorporated herein by reference.

[0171] As another example, a slurry of α-1,3-glucan with approximately 100% α-1,3-glycosidic bonds was prepared from an aqueous solution (0.5 L) adjusted to pH 5.5 containing the following: *Streptococcus salivarius* gtfJ enzyme (100 units / L), sucrose (100 g / L), potassium phosphate buffer (10 mM), and FermaSure® antimicrobial agent (100 ppm), as described in U.S. Patent Application Publication No. 2013 / 0244288 (incorporated herein by reference). The resulting enzyme reaction was maintained at 20°C–25°C for 24 hours. Since the α-1,3-glucan synthesized in the reaction is water-insoluble, a slurry was formed. The α-1,3-glucan solids were then collected on 40-micron filter paper using a Buchner funnel equipped with a 325-mesh sieve.

[0172] The weight-average degree of polymerization (DPw) of the α-1,3-glucan used in this study was approximately 800.

[0173] Preparation of hybrid α-1,3-glucan hydrogels and aerogels:The preparation of the self-supporting hybrid α-1,3-glucan hydrogel was carried out using an acid-assisted co-precipitation method. Briefly, 0.6 g of α-1,3-glucan particles were dispersed in 10 mL of deionized water for 2 minutes, followed by the addition of 1 mL of 8 M NaOH solution. The preparation was maintained with continuous stirring for 10 minutes until a clear solution was obtained; the pH of this solution (stock solution) was > 13.35. 4.16 mL of this stock solution was added to separate solutions of different inorganic salts (or simply to water to prepare a pure solution); for the pure α-1,3-glucan solution, the pH was recorded as 13.13. According to this method, insoluble metal hydroxides were generated in situ via NaOH hydrolysis. Each metal hydroxide / α-1,3-glucan preparation (or pure α-1,3-glucan solution) was then partially neutralized with 0.2 mL of 1% acetic acid solution (resulting in pH 12.9 for pure α-1,3-glucan solution), which led to gelation, thereby obtaining a self-supporting hydrogel after 72 hours (allowing hydrogel formation without agitation). Three different inorganic salts (MgCl2·6H2O, CaCl2·2H2O, and Ti[OCH(CH3)2]4) were used as precursors for the in-situ generation of metal hydroxides Mg(OH)2, Ca(OH)2, and Ti(OH)4. MgCl2·6H2O and CaCl2·2H2O solutions were prepared by dissolving specific amounts of the salts in deionized water, followed by the addition of an α-1,3-glucan stock solution. For Ti(OH)4 formation, a specific amount of Ti[OCH(CH3)2]4 was hydrolyzed in ethanol, followed by the addition of an α-1,3-glucan stock solution. α-1,3-glucan hydrogels with varying amounts of metal hydroxide were produced, and a pure α-1,3-glucan control hydrogel (pure hydrogel) (without the use of inorganic salts) was also prepared for comparison. The hydrogels were thoroughly washed by immersion in deionized water until each hydrogel had a neutral pH. The hydrogels were then frozen at 20°C for 4 hours, followed by freeze-drying at 105°C for 72 hours to obtain the final aerogel. Hybrid dextran aerogels with varying levels of metal oxides (e.g., about 2 wt% or 10 wt%) were prepared; unless otherwise disclosed, the hybrid dextran aerogels studied below contained about 2 wt% metal oxides.

[0174] Rheological and compressive strength assessment:Hydrogel strength measurements over time were performed using a stress-controlled rotational rheometer (Anton Paar MCR-302) with a cone / plate geometry. Storage (G') and elastic (G'') moduli were measured within a linear viscoelastic envelope at a frequency of 1 Hz, a temperature of 25°C, and a strain (γ) value of 1.58%. Oscillatory strain scans were performed at 25°C using a 1 mm gap size. A solvent shield was used to prevent dehydration of the hydrogel samples during measurements. The same instrument setup was used to examine the compressive strength of the aerogels in both dry and water-absorbed forms. For each of the prepared dextran aerogels, cylindrical aerogels of similar height (approximately 20 mm) and diameter (approximately 16 mm) were used for compressive strength testing at a speed of 5 mm / min. Rheological measurements of each aerogel in water were performed by adding 10 mL of DI water to a cylindrical tube containing a known weight of aerogel. After 100 s (expected to be the maximum immersion time for the aerogel to be water-saturated in this study), the aerogel was removed from the water, excess water around its walls was wiped dry with paper, and then rheological tests were performed. For each measurement, the yield stress was considered as the endpoint of the elastic region of the aerogel, while the compressive Young's modulus was estimated from the stress-strain diagram using the linear region of the normal force (N) against the time curve, as given in Equations 1 and 2:

[0175] Stress = F / A (Equation 1), where F is the normal force (N) and A is the area of ​​the cylindrical sample.

[0176] Strain = ΔL / L (Equation 2), where ΔL is the length of the stretch and L is the original length.

[0177] Hydrogel density assessment: The density (ρ) of each hydrogel was evaluated using Equation 3.

[0178] ρ = w / v (Equation 3), where ρ is the density, w is the weight of the cylindrical hydrogel, and v = πr 2 h (where r is the radius and h is the height).

[0179] The weight of each sample was measured using a fully calibrated weighing balance with a readability of 0.0001 g, and the diameter and height were determined using electronic digital calipers. Each hydrogel and aerogel sample was prepared into a cylindrical shape using a molding machine for density measurements.

[0180] Confocal laser scanning microscope (CLSM):The internal structure and pore size of each hydrogel were examined using a Leica SP8 CLSM instrument. An emission wavelength of 615 nm was selected to measure the light reflectance of the dextran, successfully revealing the hydrogel structure. Images were acquired using an oil immersion objective (63x). A sample was dropped onto a microscope slide and covered with another slide, gently pressed to remove trapped air. The sample was then imaged. Images of methylene blue-labeled aerogels were collected using the same instrument, and the results were used to interpret the structural integrity of the aerogels in water. For this purpose, samples were first labeled with methylene blue for 2 and 100 seconds, and images of the methylene blue attached to the aerogel walls were then collected using excitation and emission wavelengths of 668 and 688 nm.

[0181] Scanning electron microscope (SEM): The surface morphology of the aerogel was examined using a SEM (FEG 250 FESEM) with an accelerating voltage of 10 kV. The instrument was equipped with energy-dispersive X-ray spectroscopy (EDAX) for elemental mapping and analysis. Sample preparation was performed by directly mounting the sample onto a carbon strip attached to a sample holder. Images were collected at different magnifications of 1000x, 5000x, and 100000x to examine open pores, wall thickness, and mesopores, respectively.

[0182] X-ray scattering: X-ray diffraction (XRD) spectra of the aerogel were captured using a MINIFLEX 600 X-ray diffractometer (Rigaku, Japan). The diffraction patterns were obtained using monochromatic Cu Kα radiation (λ = 0.1542 nm, voltage = 40 kV, and current = 15 mA) at 1 (°)·min. -1 The scanning rates were collected in the 2θ range of 5 to 80°. The crystallite size of the metal oxides (i.e., MgO, CaO, TiO2) in the basal plane of each hybrid aerogel was determined by the diffraction peak with the highest intensity using the Debye-Scherrer relation (Equation 4).

[0183] (Equation 4), where k is the shape factor (0.9), λ is the X-ray wavelength (0.154 nm), and β hkl It is the full width at half maximum (FWHM), and θ hkl It's Prague Cape.

[0184] Fourier transform infrared spectroscopy (FTIR) measurement: Fourier transform infrared spectroscopy (FTIR) spectroscopy (400-4000 cm⁻¹) -1 Measurements were collected using a Cary 630 FTIR spectrometer with an attenuation transmission accessory. Sample transmittance was collected against the background of the instrument used for data collection.

[0185] Nitrogen porosity measurement: Nitrogen adsorption-desorption measurements were performed at 77 K in an instrument (GERMINI VII, Micromeritics). Prior to data collection, the aerogels were pretreated, and the instrument was degassed at 120°C for 2 hours to remove any form of adsorbed moisture. The specific surface area and pore volume for each sample were estimated using the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods.

[0186] Thermogravimetric analysis (TGA): The TGA was performed using an EXSTAR TG / DTA 6300 instrument (SIINanoTechnology Inc.). Data were collected by heat-treating the aerogel at a heating rate of 5°C / min under a nitrogen atmosphere (flow rate of 100 mL) from room temperature (RT, 20°C) to 600°C. The operating temperature for the TGA was maintained between 20°C and 600°C.

[0187] X-ray photoelectron spectroscopy (XPS) analysis: The chemical state of the elements in each sample was examined using an X-ray photoelectron spectrometer (XPS, VG ESCALAB 250, Thermo Scientific) calibrated at 284.4 eV using C 1s. For each element, the obtained sub-peak composition was partially assigned using a combination of CASAXPS software and Gaussian-Lorentz functions.

[0188] Fluid absorption and retention measurements: Three different model fluids were used to study the fluid absorption capacity of the aerogel: DI water as the baseline, saline as the urine model, and glycerol / water as the menstrual fluid model.

[0189] The experimental inflow rate, fluid absorption capacity, and retention capacity were evaluated. In the first experiment, the aerogels were tested without any loading applied to their surface (“w / o loading”). In the second experiment, a loading was applied to the top of each aerogel (i.e., under-loading adsorption experiment), and its fluid absorption performance was evaluated. The initial weight of each aerogel was measured using an analytical balance with a readability of 0.0001 g. The aerogels were then placed in a container containing 10 mL of model fluid. The soaked aerogels were then removed from the fluid, and excess fluid was removed with paper. The aerogels were allowed to stand on new paper for 5 minutes until all fluid on their walls was dry, after which the wet weight was measured. The fluid absorption capacity of each aerogel was calculated by subtracting the weight of the dried aerogel from its wet weight, dividing that difference by the dry weight, and multiplying by 100. The average of three consecutive absorption capacity measurements for each aerogel was determined.

[0190] To determine the fluid absorption and retention of each aerogel under load, a sintered glass filter plate (porosity = 80 mm, h = 7 mm) was placed in a cylindrical container of expanded polyethylene foam. A polyester mesh was then placed on the filter plate to separate the aerogel sample from the plate. The entire setup was then placed in a petri dish. A dried aerogel sample (10 mg) was placed on top of the polyester mesh surface. A cylindrical solid weight (100 g stainless steel) was placed on the sample. Then, 10 mL of fluid solution was added to the setup. After different time intervals (2 to 100 seconds), each aerogel sample was removed and allowed to stand on paper for 5 minutes until all surface water was dry. The absorption capacity of the sample was calculated as described above. The average of three consecutive absorption capacity measurements for each aerogel was determined.

[0191] The centrifugation retention capacity (CRC) of each aerogel was measured as follows. The dry aerogel sample was immersed in the model liquid (10 mL). The immersed aerogel was then wiped dry with paper and air-dried for 5 minutes, followed by centrifugation in a centrifuge tube equipped with a filter (EPPENDORF 5810). The weights of the aerogel samples centrifuged at 400 rpm, 700 rpm, 2000 rpm, and 3000 rpm were obtained at different times. The CRC was then calculated using Equation 5:

[0192] (Equation 5), where w CRC It is the weight of the centrifuged aerogel, and w o This is the weight of the dried aerogel. Determine the average of three CRC measurements for each aerogel.

[0193] The kinetics related to the aerogel's absorption capacity are studied using both pseudo-first-order and pseudo-second-order rate laws. Equations 6 and 7 show the integral forms of the pseudo-first-order and second-order rate laws, respectively:

[0194] (Equation 6)

[0195] (Equation 7)

[0196] or (g / g) is the maximum absorption capacity of the aerogel. or (g / g) is the absorption capacity at a specific time. t is the time the aerogel is in a container containing DI, water, or other fluids. k1 is the pseudo-first-order absorption rate constant and can be used as... The slope of the t-curve is obtained from Equation 6. k2 is the pseudo-second-order absorption rate constant, which is (t / q)t The intercept of the t-curve × The reciprocal of (Equation 7).

[0197] The hydrophilicity of the aerogels was examined. All aerogels exhibited a zero contact angle with water, indicating that they are hydrophilic. To further reveal the differences in hydrophilicity among aerogels, aerogels of similar density were dropped into DI water, perylene oil / water solution, or perylene / canola oil / water solution, and their behavior in each solution was compared.

[0198] Results and discussion

[0199] Material synthesis: Self-supporting hydrogels containing metal hydroxides (Mg(OH)2, Ca(OH)2, or Ti(OH)4) and α-1,3-glucan (hybrid hydrogels in this paper) were synthesized using precipitation methods in which the organization of glucan particles was successfully controlled using inorganic salts such as MgCl2·6H2O, CaCl2·2H2O, or Ti[OCH(CH3)2]4. Figure 1 This illustrates a typical scheme used in this paper for the synthesis of hybrid hydrogels and hybrid aerogels. In the first step (by... Figure 1 In the three leftmost flasks (representing the three flasks), a stock solution of 6 wt% α-1,3-glucan in an aqueous NaOH solution (pH approximately 13.45) is mixed with an inorganic salt solution to form a formulation of dissolved α-1,3-glucan and insoluble Mg(OH)₂, Ca(OH)₂, or Ti(OH)₂. In this formulation, it is believed that the insoluble metal hydroxide interacts with the dissolved α-1,3-glucan via intermolecular hydrogen bonding. In the following steps (by... Figure 1 The three rightmost flasks (representing the three flasks in the image) partially neutralize the preparation with acetic acid solution to initiate the gelation process, forming a hydrogel of α-1,3-glucan and metal hydroxide. The hydrogel is washed with water and then freeze-dried to form an aerogel. Thus, hybrid hydrogels containing α-1,3-glucan and metal hydroxide [Mg(OH)₂, Ca(OH)₂, or Ti(OH)₂] are prepared, as are hybrid aerogels containing α-1,3-glucan and metal oxides (MgO, CaO, or TiO₂). In contrast to "pure hydrogels" containing only α-1,3-glucan, these materials are referred to herein as "hybrid hydrogels" and "hybrid aerogels."

[0200] Gelation kinetics of hydrogels:After 2 hours of standing, the unneutralized pure α-1,3-glucan (2 wt%) solution did not show gelation due to the relatively high solubility of α-1,3-glucan at high pH ≥ 13.13. However, complete gelation was observed after 72 hours, due to the removal of the cap from the vial containing the sample and exposure to the surrounding environment, resulting in a decrease in water content. With the removal of water, particle-particle physical interactions increased, and gelation began. Adding 0.2 mL of 1% acetic acid to the α-1,3-glucan solution resulted in significant gelation after 2 hours and the formation of a hydrogel with better stability at 72 hours. This indicates that the partial neutralization process aids gelation kinetics by precipitating the dissolved α-1,3-glucan chains, which in turn induces rapid interactions of the hydroxyl groups of the dextran particles for faster gelation.

[0201] Next, the pH values ​​favorable for gelation and hydrogel formation were investigated. It was found that hydrogel formation was mostly rapid when the solution pH was maintained between 12.80 and 13.0 (at which point 80% to 90% of the particles precipitated). Sulfuric acid and acetic acid were investigated for lowering the pH, with fairly stable hydrogels of pure α-1,3-glucan obtained at pH values ​​of 12.98 and 12.91, respectively, after standing for 2 hours (without continuous mixing / stirring). Based on this, a pH less than 13.0 was used to prepare hydrogels in this study. The introduction of 2 wt% inorganic salts (MgCl2·6H2O, CaCl2·2H2O, or Ti[OCH(CH3)2]4) further increased the gelation rate, with Ti(OH)4 / glucan, Mg(OH)2 / glucan, and Ca(OH)2 / glucan obtained at pH values ​​of 12.96 and 12.86, respectively. Gelation of each inorganic salt / α-1,3-glucan solution initiated immediately and formed a stable hydrogel within 30 minutes. This indicates that the in-situ generated metal hydroxides [Mg(OH)₂, Ca(OH)₂, or Ti(OH)₄] improve particle-particle interactions, thereby enhancing gelation.

[0202] The differences in gelation kinetics of hydrogels after the introduction of inorganic salts were investigated by performing oscillation time-scan tests. The storage modulus (G') and loss modulus (G'') of hybrid α-1,3-glucan hydrogels (2 wt% inorganic dry solids [dsb] [dsb is also referred to herein as dry heavy base, or dwb]) and pure α-1,3-glucan hydrogels were evaluated. For the pure α-1,3-glucan hydrogel, an increase in storage modulus was observed after approximately 40 minutes of gelation time. In contrast, the hybrid compositions exhibited an immediate increase in G', but the slope of this increase differed. Ca(OH)2 / glucan showed a linear evolution of G', while Ti(OH)4 / glucan and Mg(OH)2 / glucan showed nonlinear growth. None of these hydrogels reached a plateau within 60 minutes of gelation, indicating continuous microstructural evolution of the hydrogels. The non-monotonic increase in G' indicates a strong interaction between the inorganic material and α-1,3-glucan, leading to the formation of a non-covalently cross-linked structure. Interestingly, the Mg(OH)2 / glucan hydrogel, followed by the Ti(OH)4 / glucan and Ca(OH)2 / glucan hydrogels, exhibited large G's at the onset of gelation and proceeded at a high gelation rate, indicating more pronounced coupling between their constituent particles, resulting in rapid network formation.

[0203] Network structures of hydrogels and aerogels: To explore the microscopic origins of these significant differences in gelation kinetics, non-invasive imaging was performed using the reflectance mode of CLSM. Images were acquired for all samples at a gelation time of 2 hours. Pure α-1,3-glucan hydrogels exhibited a larger reflectance domain size compared to hybrid dextran hydrogels, indicating greater aggregation between dextran particles in the pure α-1,3-glucan hydrogel. The introduction of metal hydroxides resulted in a significantly different particle spatial distribution, largely influenced by the ionic radius of the metal cation. Ca2+ with an ionic radius of 100 Å was present. 2+ This results in hydrogels with open honeycomb structures, while Mg has smaller ionic radii of 72 Å and 61 Å. 2+ and Ti 4+ Hybrid hydrogels with very dense particulate networks were generated. These results are consistent with the rheological responses of these hydrogels. The dense Mg(OH)₂ / dextran microstructure resulted in the highest modulus and the fastest gelation kinetics, followed by those with less dense Ti(OH)₄ / dextran and the least dense Ca(OH)₂ / dextran microstructures.

[0204] The Brunauer-Emmett-Teller (BET) specific surface area was evaluated for pure dextran aerogel and the selected hybrid (2 wt% inorganic) aerogel. The TiO2 / dextran aerogel exhibited a specific surface area of ​​82.1058 m².2 The highest BET specific surface area per g is almost twice that of pure dextran aerogel. Considering Ti 4+ The smaller ionic radius and tetravalent nature of TiO2 facilitate the multidentate bonding of TiO2 with dextran particles, resulting in smaller pore sizes and a higher pore volume / aerogel mass (0.1371 cm⁻¹). 3 This phenomenon ( / g) facilitates the adsorption and desorption of N2 gas, resulting in a higher surface area. The small ionic radius of the metal has also been revealed in MgO / dextran aerogels to contribute to the design of small pore sizes and high pore volumes (0.0883 cm³). 3 The effect of / g), particularly on CaO / dextran aerogel (37.1272 m 2 Compared to g), MgO / dextran aerogel achieved 53.3294 m³. 2 The CaO / dextran aerogel exhibits a higher surface area per g. The larger pore size, along with weak adsorption and retention of purged N2 gas, results in a smaller pore volume (0.0617 cm⁻¹). 3 / g). The surface area of ​​the pure dextran aerogel is 44.6942 m². 2 / g, while its pore volume is 0.0748 cm³. 3 / g.

[0205] Identification of functional groups in hydrogels: To understand the functional groups in hybrid and pure dextran hydrogels, FTIR was used to examine the chemical groups of the samples. Specific amounts (approximately 5 mg) of each hydrogel were placed in a VERTEX 70 FTIR spectrometer, and transmittance was collected against the instrument background (i.e., a copper plate sample holder). FTIR spectra of Ti(OH)4-dextran hydrogels (with transmittance at 3282.62 cm⁻¹) are shown. -1 The OH stretching vibration at [0.05] decreases with increasing Ti[OCH(CH3)2]4 salt loading, indicating that the dextran is functionalized via intermolecular hydrogen bonding. The peaks at 2987.14 and 1635.29 may be related to the CH and CO stretching vibrations of the methylene and carbonyl groups of the polysaccharide, respectively, as they appear with similar intensities in the spectra of pure dextran hydrogels and Ti(OH)2-dextran hydrogels with different Ti[OCH(CH3)2]4 loadings. However, due to intramolecular hydrogen bonding of the polysaccharide molecules, pure dextran shows a lower intensity at 1044.32 cm⁻¹. -1 The CO bending mode appears relatively broad at this point. After the introduction of Ti[OCH(CH3)2]4, the peak becomes sharper with increasing intensity, due to in-situ generation of Ti(OH)4 undergoing intermolecular hydrogen bonding with the dextran molecule. The peaks at 875.23 and 435.02 cm⁻¹ are also observed. -1The new peaks appearing can be attributed to the interactions between Ti-OH and Ti-O-Ti, with sharpness increasing with increasing Ti[OCH(CH3)2]4 loading. The increase in TOH vibration corresponds to a decrease in the OH stretching mode, indicating that the dextran is functionalized by Ti(OH)4.

[0206] To confirm that the Ti[OCH(CH3)2]4 salt hydrolyzes to Ti(OH)4 in alcohol prior to its introduction into the dextran solution for hybrid hydrogel formation, a slight increase in pH from 5.94 to 7.34 was recorded. Furthermore, FTIR analysis was performed to confirm the hydrolysis of Ti[OCH(CH3)2]4 to Ti(OH)4. After adding alcohol to Ti[OCH(CH3)2]4 and stirring for 10 min, a pH of 3360.0 cm⁻¹ was recorded. -1 A slight increase in the intensity of the OH stretching mode, and at 1620.15 cm. -1 The formation of a new OH- bending vibration at this site indicates hydrolysis. Ti[OCH(CH3)2]4 at 900 cm⁻¹ -1 The disappearance of the asymmetric and symmetric signals of OCH(CH3)2, and the formation of CO stretching mode in hydrolyzed Ti[OCH(CH3)2]4, further indicate the formation of Ti(OH)4.

[0207] Different phenomena were observed using the spectra of Mg(OH)₂-dextran and Ca(OH)₂-dextran hydrogels, revealing that the stretching modes of OH and CO were similar to those of pure dextran. These phenomena were observed in the spectral range of 1600 to 400 cm⁻¹. -1 High-magnification spectra within the range showed that the CO bending mode of the hybrid hydrogel shifted to lower wavenumbers, and the peak gradually disappeared with increasing loading of Ca or Mg salts (above), indicating dextran functionalization. 424.07 cm⁻¹ -1 The peak at 422.07 cm⁻¹ represents the Mg-O / Mg-O-Mg vibration, and the peak increases with increasing Mg salt loading. For Ca(OH)₂-dextran hydrogel, the peak value is 422.07 cm⁻¹. -1 The peak at that point can be assigned to the Ca-O / Ca-OH vibration on the dextran, thus proving the functionalization of the dextran.

[0208] Hydrogel density characterization: The density of the hydrogel shows some effects on the properties of the aerogel. Compared with pure dextran hydrogels, the hybrid hydrogels produced above exhibit considerable stability in water when the inorganic salt loading used in hydrogel production is < 20 wt% (dsb); above this level, the hybrid hydrogels lose their mechanical strength and disperse in water.

[0209] Furthermore, significantly lower hydrogel densities were observed in water when the inorganic salt loading exceeded 8 wt% (dsb), particularly for the Ti(OH)₂-glucan hydrogel. For all hybrid hydrogels, the initial density increased with increasing inorganic salt loading during hydrogel synthesis. Depending on the molecular weight of the metal, each hybrid hydrogel exhibited an optimal density at different inorganic salt loading levels. Specifically, the optimal densities for Mg(OH)₂ / glucan, Ca(OH)₂ / glucan, and Ti(OH)₄ / glucan hydrogels were found to be at inorganic loadings of 3 wt%, 8 wt%, and 2 wt% (all dsb), respectively. At a 2 wt% (dsb) inorganic salt loading, the Mg(OH)₂-glucan, Ca(OH)₂-glucan, and Ti(OH)₄-glucan hybrid hydrogels exhibited densities of approximately 964.2, 992.1, and 997.2 kg m³, respectively. -3 The density.

[0210] Crystallization structure and phase analysis of aerogels: XRD analysis was used to investigate the crystal structure of hybrid and pure dextran aerogels. The pure aerogel exhibited a hexagonal phase corresponding to JCPDS number 48-1206. Three significant diffraction peaks were observed at 2θ degrees and crystal planes at 9.6°, 18.1°, and 21.9°. This indicates a high crystallinity of the pure aerogel, and the average crystallite size was found to be 71.6 nm.

[0211] The hybrid aerogel retains a nanocrystalline structure, and the metal (inorganic) components exhibit a hexagonal structure resembling the crystal pattern of dextran. XRD analysis revealed that the inorganic components in the hybrid aerogel are in oxide form, indicating that freeze-drying converts the metal hydroxide (of the hydrogel) into metal oxides through water removal. In the crystal structure of the TiO2-dextran aerogel, the TiO2 peaks match well with JCPDS card number 33-1381. The main peaks of TiO2 were found at 31.5°, 33.5°, 37.2°, 39.0°, 55.1°, 57.2°, and 61.3°, with crystal planes of (0 0 2), (2 1 1), (3 0 1), (2 2 0), (4 11), (2 1 3), and (4 2 0), respectively. Using Scherer's equations, the average crystallite size of TiO2 was calculated to be 34.4 nm. Smaller crystallite size facilitates the growth of TiO2 nanocrystals in dextran networks.

[0212] In addition to the crystal faces of the polymorphs of dextran, CaO-dextran aerogel exhibits additional peaks at 24.1°, 26.7°, 29.7°, 35.5°, 39.4°, 43.2°, 47.5°, and 48.3°, which are assigned to the CaO crystal face with JCPDS number 28-0775. The average crystallite size of CaO was found to be 43.1 nm.

[0213] The crystal structure of the MgO-dextran aerogel exhibits additional peaks for MgO and Mg(OH)2, corresponding to JCPDS numbers 30-0794 and 07-0239, respectively. The presence of Mg(OH)2 in the aerogel can be attributed to the hygroscopic properties of MgO. The main peak of Mg(OH)2 overlaps with MgO at 38.0° with a crystal plane of (1 0 1), indicating that MgO is converted in situ to Mg(OH)2 under ambient conditions after the aerogel product is removed from the freeze dryer. Mg(OH)2 has other crystal planes of (0 0 1), (1 0 0), (1 0 2), (1 1 0), (1 11), (1 0 3), and (2 0 0), while MgO exhibits crystal planes of (4 0 0), (5 1 1), and (4 4 0). The average crystallite sizes of Mg(OH)2 and MgO in MgO-dextran aerogel were found to be 31.5 nm and 29.2 nm, respectively.

[0214] The hybrid aerogels prepared above contain 0.5 wt%, 2 wt%, or 10 wt% TiO2, CaO, or MgO / Mg(OH)2. For all hybrid aerogels, increasing the metal oxide component (and hydroxide component, if Mg) alters the crystallinity and crystallite size of the dextran. When the metal component is >2 wt% of the hybrid aerogel, high crystallinity is recorded, and the crystal plane shift from 9.6° to 10.4° indicates a dehydrated form of the dextran. This clearly demonstrates that controlling the concentration of the inorganic precursor (metal salt) allows for the preparation of hybrid aerogels with controlled physicochemical properties. In short, the metal oxide / hydroxide component can be used to design the crystallite size and interlayer spacing of α-1,3-glucan.

[0215] Morphology and elemental composition of aerogels: Pure aerogels and hybrid aerogels (2 wt% inorganic matter) were macroscopically recorded by SEM.

[0216] When compared to hydrogels cast in a cylindrical mold, the corresponding aerogels exhibit similar lengths, but with a slight reduction in diameter of approximately 2.5%.

[0217] SEM was used to reveal the surface structure and morphology of pure dextran aerogels and hybrid aerogels. SEM imaging showed that each aerogel exhibited a characteristic honeycomb microstructure with an interwoven network of open porous surfaces. The honeycomb microstructure of the pure dextran aerogel showed a torn morphology along the growth direction of the hexagonal-like honeycomb microstructure. Figure 2 a). Open pores are approximately 10 to approximately 20 µm, and typically occur between stacked layers of a honeycomb structure with an average thickness of approximately 1.4 µm. Figure 2 (Illustration). The pore walls contain nanosheet structures with an average thickness of about 0.545 µm and randomly distributed nanopores with diameters ranging from 50 to 250 nm.

[0218] Hybrid aerogels exhibit morphological changes due to the unidirectional growth of microstructures with hexagonal prism shapes. Figure 2 (ad). Compared to pure dextran aerogels, hybrid aerogels also exhibited fewer or no tearing morphologies. This indicates that the hybrid aerogels have excellent mechanical strength, which facilitates the unidirectional, twist-free growth of the honeycomb microstructures with hexagonal prism shapes. Other interesting features observed are the increased thickness of the nanosheets in the honeycomb microstructures and the smaller pore size of the nanosheets. The open pores existing between the intermediate layers of the MgO-dextran aerogel nanosheets have an average size of approximately 8 µm ( Figure 2 b), and the nanosheets have a thickness of 2.5 µm ( Figure 2 (Illustration in b). Furthermore, the nanosheets exhibit pore sizes ranging from 10 to 150 nm, as measured along the x-axis.

[0219] Because the open pores in the intermediate layer are approximately 8.5 µm ( Figure 2 c), and the nanosheet thickness is 1.5 µm; CaO-dextran aerogel exhibits similar phenomena ( Figure 2 (Illustration c); the pore size at the nanosheets ranges from 10 to 170 nm, slightly larger than that of the nanosheets in the MgO-dextran aerogel. This suggests that the radius of the metal ions may also play a role in the pore size arrangement, similar to what is observed in hydrogels. The greater reduction in open pore size and the increase in nanosheets can be attributed to the growth of metal oxides along the basal plane of the dextran, which may explain the higher mechanical strength observed in the hybrid hydrogel. However, among the hybrid aerogels, the TiO2-dextran aerogel exhibits the smallest open pore size and the thickest nanosheets, found to be 7.8 µm ( Figure 2 d) and 2.7 µm ( Figure 2(Illustration d); The smallest pore size was also found at the nanosheets, ranging from 5 to 140 nm. This indicates that the transition metal oxide TiO2 can exhibit multivalent hydrogen bonding with dextran due to the tetravalent nature of Ti metal. This also explains the superior mechanical strength observed in Ti(OH)4-dextran hydrogels.

[0220] EDS analysis was used to estimate the chemical composition of pure dextran and hybrid dextran aerogels. The dominant peaks appearing in the EDS spectra can be assigned to elements within the aerogel. A favorable Ti distribution was observed in TiO2-dextran aerogel compared to the distributions of Mg and Ca in MgO-dextran and CaO-dextran aerogels, respectively. This can be attributed to the tetravalent nature of Ti, which allows for multivalent hydrogen bonding with dextran.

[0221] Identification of functional groups in aerogels: FTIR spectroscopy was used to further examine the structures of both the pure dextran and the hybrid aerogel to identify different functional groups in the materials. (Except for the hybrid aerogel, which contains structures in the < 500 cm⁻¹ region...) -2 Apart from the additional vibrational bands at lower wavenumbers, pure dextran and hybrid aerogels exhibit similar FTIR spectra. The additional peaks are characteristic vibrational bands of the metal-oxygen-metal (MOM) signal. This indicates that the molecular structure of dextran is somehow preserved after the incorporation of metal oxides.

[0222] Between 400 and 1600 cm -1 Detailed analysis of the region revealed details of the vibrational bands associated with metal oxides in the hybrid aerogel. Figure 4 b). For MgO-dextran aerogel, at 450.72 cm⁻¹ -1 The other peak at this location can be attributed to the Mg=O / Mg-O-Mg signal, and the CaO-dextran aerogel at 430.19 cm⁻¹... -1 The peak at 431.19 cm⁻¹ is assigned to the Ca=O / Ca-O-Ca vibrational band. TiO₂-dextran aerogel has a peak at 431.19 cm⁻¹. -1 Vibrational peaks are shown at [value], which are vibrational bands of the Ti-O-Ti / Ti=O interaction. Depending on the availability of the metal (“M”) species, the vibrational bands of the M=O / MOM species exhibit different intensities in the hybrid aerogels. For example, in the hybrid aerogels at a 2 wt% metal oxide level, the band intensity of the Mg-O-Mg species is somewhat the highest compared to the Ca=O / Ca-O-Ca and Ti=O / Ti-O-Ti species. However, in the case of pure dextran aerogels, these peaks are almost absent. This demonstrates that both pure dextran and hybrid aerogels were successfully synthesized via a co-precipitation method, with only the precursor of the inserted metal oxide being modified.

[0223] Furthermore, based on FTIR analysis of the hydrogels, the OH stretching bands of the hybrid aerogels are expected to exhibit different behavior compared to pure dextran aerogels. This will further aid in understanding the chemical interactions between dextran and metal oxides. To reveal this, each aerogel was subjected to FTIR at 4000 to 3100 cm⁻¹. -1 The spectrum was expanded and carefully analyzed. Compared to the OH stretching bands of pure dextran aerogels, the OH stretching bands of hybrid aerogels exhibited a wider shape with reduced transmittance intensity. These characteristics can be attributed to the inclusion of metal oxides leading to the disruption of intramolecular hydrogen bonds in dextran and the formation of intermolecular hydrogen bonds between the metal oxides and dextran. Among the hybrid aerogels, the OH stretching mode of TiO2-dextran aerogels had the lowest intensity, indicating superior chemical interactions and networking between TiO2 and dextran. Furthermore, the OH stretching bands of CaO-dextran aerogels underwent a slight shift to a lower frequency region, suggesting that Ca-O species may contribute to wider interlayer distances between dextran crystal planes, similar to what is observed in hydrogel analysis.

[0224] Thermogravimetric analysis (TGA) of aerogels

[0225] The thermal stability of pure dextran and hybrid dextran aerogels was examined using TGA at temperatures ranging from 20°C to 600°C. The heat resistance versus temperature curves for the prepared aerogels show that the pure dextran aerogel exhibits an initial weight loss at a lower temperature compared to the hybrid dextran aerogels (each containing 2 wt% metal oxide). This indicates that the aerogel composition affects thermal stability. For example, the initial weight loss (approximately 7%) of the pure dextran aerogel occurs at approximately 60°C due to the removal of surface moisture. Subsequently, a second weight loss (11%) occurs at approximately 205°C due to the removal of moisture trapped within the structure. This gradual weight loss was not observed in the case of the hybrid aerogels (each containing 2 or 10 wt% metal oxide), indicating that the hybrid aerogels have better stability in a moisture-containing atmosphere. For the hybrid aerogels (each containing 2 wt% metal oxide), only a 5% weight loss was observed at 260°C, while for the hybrid aerogels containing 10 wt% MgO or CaO, this initial weight loss occurred at 175°C. However, for the hybrid aerogels containing 10 wt% TiO2, an initial weight loss of approximately 5% occurred at 210°C.

[0226] Pure dextran aerogels exhibited a sharp weight loss (91%) starting at 200°C and ending at 420°C, likely due to thermal degradation of the dextran. However, all hybrid aerogels containing 2 wt% metal oxides showed superior heat resistance profiles, with all samples exhibiting a sharp weight loss (approximately 90%) starting at 250°C and ending at 420°C. The remaining weight (which is the inorganic phase) remained until 475°C–600°C, depending on the type of metal oxide present. In hybrid aerogels containing 10 wt% metal oxides, a different weight loss and lower heat resistance were observed. The sharp weight loss started at approximately 170°C and ended between 350°C and 380°C, depending on the metal oxide present.

[0227] Chemical and surface-mediated properties of aerogels: XPS was used to elucidate the functional groups and surface-mediated properties of the aerogels. Hybrid dextran aerogels (2 wt% metal oxides) were used for XPS analysis because samples with higher metal oxide content exhibited poorer thermal stability and structural integrity (see TGA analysis above). Both pure dextran and hybrid dextran aerogels showed four significant peaks that could be assigned to oxygen (O) and carbon (C). However, the spectra were analyzed to reveal the presence and chemical interactions of metal oxides on the dextran surface. Peaks associated with Mg 2p, Ca 2p, and Ti 2p were detected on MgO-dextran, CaO-dextran, and TiO2-dextran aerogels, respectively. These peaks were deconvolved along with the O and C peaks to determine their chemical states. Sub-peak components for each element were assigned using Gaussian-Lorentz functions.

[0228] Observe the deconvolution peaks of oxygen in all aerogels. The O 1s of pure dextran aerogels show two deconvolution peaks at approximately 529.87 and 530.29 eV, which can be assigned to C=O and OCO interactions within the polysaccharide structure. These peaks undergo slight alterations in hybrid dextran aerogels, with the C=O signal shifting to higher binding energies of approximately 530.08, 530.07, and 530.08 eV for TiO2-dextran, CaO-dextran, and MgO-dextran aerogels, respectively. An increase in the intensity and coverage of the C=O signal is also observed in hybrid dextran aerogels. This is due to the presence of TiO2, CaO, or MgO at the basal plane of the dextran, leading to an increase in the vibrational band of C=O. This indicates surface functionalization of the dextran. Furthermore, the OCO signal of the hybrid dextran aerogel appears at a similar binding energy position (approximately 530.29 eV) to that of the pure dextran aerogel, but with reduced intensity. This indicates a trade-off between intramolecular and intermolecular hydrogen bonding after surface functionalization with TiO2, CaO, and MgO (intermolecular hydrogen bonding between α-glucan hydroxyl groups and metal oxides increases, while intramolecular hydrogen bonding between α-glucan hydroxyl groups decreases). The TiO2-dextran aerogel shows an additional peak at 530.20 eV, corresponding to the Ti-O interaction in the structure. For CaO-dextran and MgO-dextran aerogels, additional peaks of Ca-O and Mg-O / Mg-(OH)2 interactions can be found at 529.90 and 530.24 eV, respectively.

[0229] Observe the C1s sub-components in the aerogels. The C1s peak of the pure dextran aerogel can be deconvoluted into three sub-peaks, while the C1s peak of the hybrid dextran aerogel can be deconvoluted into four sub-peaks. The three C1s sub-components of the pure dextran aerogel have peaks at 282.16, 283.83, and 285.20 eV, assigned to CC / CH, CO / C-OH, and OCO / C=O signals, respectively. For the hybrid dextran aerogel, the CC signal shows lower area coverage and intensity. Among the hybrid dextran aerogels, TiO2-dextran aerogel shows the CC signal with the smallest area coverage and intensity. The area coverage of the CC signal of CaO-dextran and MgO-dextran aerogels is similar, but slightly lower than that of the pure dextran aerogel. This indicates that the systematic placement of metal oxides on the dextran backbone leads to a reduction in the CC signal due to the C-Ti, C-Ca, and C-Mg interactions of TiO2-glucan, CaO-glucan, and MgO-glucan aerogels at binding energies of 284.34, 284.37, and 284.27 eV, respectively.

[0230] The XPS peaks of the metals in the hybrid aerogel exhibit poor resolution due to their quantity and interlayer trapping within the dextran structure. However, careful analysis of these peaks and their deconvolution into distinct sub-components reveals that the Ti 2p peaks can be deconvolved into four sub-components, with the peaks at 455.77 and 461.57 eV assigned to the Ti 2p of TiO2 present in the TiO2-dextran aerogel. 3 / 2 and Ti 2p 1 / 2 Species. XPS analysis revealed the possible presence of trace Ti₂O₃ phase in the sample, with Ti 2p 2 / 3 and Ti 2p 1 / 2 The binding energies are 457.69 and 464.17 eV, respectively. Deconvolving the Ca 2p peak of CaO in the CaO-dextran aerogel into two peaks, Ca 2p peaks were found at 345.15 and 348.70 eV, respectively. 3 / 2 and Ca 2p 1 / 2 Species. The Mg 2p peak of the MgO-dextran aerogel was deconvolved into two peaks at 47.74 and 49.98 eV, which can be assigned to the MgO and Mg(OH)2 phases of the aerogel, respectively. All these data indicate that the metal oxide is successfully dispersed in the structure of the dextran, resulting in a functionalized dextran aerogel.

[0231] Rheological properties of aerogels: The mechanical properties (such as yield stress and compressive modulus) of pure dextran aerogels and hybrid dextran aerogels were evaluated to determine their impact and abrasion resistance. Cylindrical aerogels were used for in-plane compression tests to obtain force (N) versus time (s) plots. Three distinct regions were observed from each plot: a linear (elastic) region, a plastic region, and a densification region. The endpoint of the elastic region was considered the yield stress (i.e., the stress point where the aerogel undergoes permanent deformation). When compared to pure dextran aerogels, hybrid aerogels exhibited a wider elastic region, with TiO2-dextran aerogels showing superior performance, followed by CaO-dextran and MgO-dextran aerogels. This indicates that hybrid aerogels exhibit stronger resistance to pore wall bending at low strain.

[0232] To better understand the mechanical behavior of aerogels, a detailed mechanical analysis was performed based on the compressive stress-strain relationship. Compressive stress-strain curves were obtained using the elastic region, and the slope of the curve was considered as the compressive modulus. Hybrid dextran aerogels exhibited ductile-like behavior throughout the strain period, especially TiO2-dextran aerogels. Stress-strain curves for pure dextran aerogels were obtained, showing yield stresses of 0.0201 kPa and compressive moduli of 0.0851 kPa. The presence of small pores and metal oxides in the microstructure of hybrid dextran aerogels led to a slight improvement in mechanical strength. MgO-dextran aerogels exhibited yield stresses and compressive moduli of approximately 0.03055 kPa and 0.06706 kPa, respectively, while CaO-dextran aerogels were found to have yield stresses and compressive moduli of 0.03015 kPa and 0.06827 kPa, respectively. TiO2-dextran aerogels exhibit the highest ductile-like behavior, with strain resistance up to 60% at yield stresses of 0.04574 kPa and compressive moduli of 0.08951 kPa. This indicates that the TiO2-dextran aerogel microstructure possesses the strongest network connectivity.

[0233] Hybrid dextran aerogels further demonstrated superior mechanical properties compared to pure dextran aerogels. Pure dextran aerogels, due to their fragile microstructure, completely fragmented into blocks under approximately 20% strain. MgO-dextran and TiO2-dextran aerogels showed no cracks throughout the compression test. Unique densification of the hybrid aerogels was observed under higher strains >30%, followed by deformation without any noticeable cracks. CaO-dextran aerogels exhibited significant cracks around the pore walls under strains >30%. This is due to the larger nanopore size in CaO-dextran aerogels, as discussed above.

[0234] The mechanical strength of dextran aerogels was investigated after 100 s of water absorption. This study was conducted by adding 10 mL of deionized water to a cylindrical tube containing a known weight of dextran aerogel. After 100 s (the expected water absorption time to saturation), the aerogels were removed and dried at room temperature for 5 minutes, followed by compression tests. Compression loading curves were prepared for each saturated aerogel. Similar to what was observed in the dried form, the hybrid dextran aerogels exhibited a slight increase in mechanical strength compared to the dextran aerogels. This suggests that the moisture environment has little or no effect on the composition of the hybrid aerogels. However, lower yield stresses and compressive moduli were recorded due to structural weakening in water. The yield stress and compressive modulus of the water-saturated pure dextran aerogels decreased to 0.00180 kPa and 5.67 × 10⁻⁶ kPa, respectively. -5kPa. MgO-dextran and CaO-dextran aerogels in water exhibit yield stresses of 0.00210 kPa and 0.00277 kPa, respectively, and a tensile strength of 7.35 × 10⁻⁶ kPa. -5 kPa and 9.38 × 10 -5 The compressive modulus was measured in kPa. Interestingly, the TiO2-dextran aerogel in water exhibited a greater increase in mechanical strength compared to the pure dextran aerogel, with a yield stress and compressive modulus of 0.00301 kPa and 0.000301 kPa, respectively. This indicates that TiO2 forms the strongest network connection with dextran, which in turn contributes to the improved mechanical strength and structural integrity of this hybrid aerogel.

[0235] Fluid absorption and retention properties: Water absorption and retention before and after compression tests were investigated using pure dextran aerogels and hybrid dextran aerogels. Without compression, the hybrid dextran aerogels exhibited superior water absorption capacity (g / g × 100) in the range of approximately 1340% to 1540% compared to the pure dextran aerogel (approximately 1057% water absorption capacity). After compression, the water retention capacity of each aerogel was found to be in the following order: pure dextran (980%) < MgO-dextran (1202%) < CaO-dextran (1247%) < TiO2-dextran (1403%).

[0236] In in-plane absorption measurements, each hybrid dextran aerogel exhibited an increased water absorption capacity over time compared to pure dextran aerogels. Figure 3 All aerogels exhibited slightly similar absorbance capacities at <30 seconds. However, TiO2-dextran aerogel showed a significantly improved absorbance capacity over an absorption period of 40 to 100 seconds, while MgO-dextran and CaO-dextran aerogels showed only minor improvements over the pure dextran aerogel over the 100-second period. Specifically, at 100 seconds, TiO2-dextran aerogel exhibited a maximum water absorbance capacity of approximately 20.0 g / g, while MgO-dextran and CaO-dextran aerogels had a maximum water absorbance capacity of approximately 17.9 g / g, and the pure dextran aerogel had an absorbance capacity of approximately 17.0 g / g. This demonstrates that hybrid dextran aerogels with 2 wt% metal oxides, particularly TiO2-dextran aerogels, can facilitate faster diffusion of water into the aerogel matrix.

[0237] The water absorption capacity of aerogels under load was also studied. Figure 3(Illustration). Water absorption under load was assessed by placing a steel weight (approximately 100 g) directly onto aerogels (approximately 100 mg) in a cylindrical container. Each aerogel under load was allowed to stand in a container with water for 100 seconds. The absorbance capacity of the dextran aerogel decreased slightly under load compared to the unloaded aerogel. Among the aerogels under load, the TiO2-dextran aerogel exhibited the highest water absorbance capacity (13.19 g / g) at 100 seconds, while pure dextran, MgO-dextran, and CaO-dextran aerogels were found to have water absorbance capacities of 9.55, 11.19, and 12.82 g / g, respectively. The water absorbance capacities of commercial diapers and commercial sanitary pads under load were also measured and found to be 43.18 and 13.90 g / g, respectively.

[0238] Also used was a NaCl aqueous solution (0.01 g / mL, "saline", urine model) Figure 4 ) or various aqueous solutions of glycerol (1:10, 1:1, 5:1 glycerol:water [menstrual fluid model]) (v / v) Figure 5A -C) The water absorption capacity of the aerogel was tested. Tests were conducted as above with and without a load. The absorption capacities of commercial diapers and sanitary pads in saline solution under load were measured to be approximately 17.50 and 4.6 g / g, respectively. The absorption capacities of commercial diapers and sanitary pads in aqueous glycerol solution under load were also measured. Figure 5C ).

[0239] Since the aforementioned aerogel absorption tests were conducted with a material (100 mg block) that is significantly larger than the particles present in diapers or pads, it is expected that reducing the hybrid aerogel described herein to smaller units / particles and using such pulverized material in diapers, pads, or other similar products would provide the product with a significant aqueous liquid absorption capacity.

[0240] Aerogel formation mechanism: Based on the in-depth understanding gained from the FTIR, XRD, SEM, TGA, rheological, and confocal results of this invention, a mechanism for aerogel formation is proposed. In the structure of α-1,3-glucan, there are two types of oxygen atoms available for intramolecular interactions (i.e., oxygen at the hydroxyl group [OH interaction] and oxygen at the ring [CO- interaction]). They can be found at C2, C4, C6 (OH groups) and C1, C3, C5 (CO groups), respectively. Due to the presence of hydrogen ions (H... + (Effect), the charge on the oxygen at the hydroxyl groups (C2, C4, C6) is more negative than that at C1, C3, and C5. Therefore, it is expected that the oxygen at C2, C4, and C6 will displace H+. + More readily reacts with cations (such as Na) + Ca + Mg+ and Ti + They interact. At high pH (e.g., >13.00), Na+... + It is excessive and therefore interacts effectively with these oxygens, leading to structural weakening and particle dissolution. For the formation of α-1,3-glucan hydrogel precursors, gelation can be induced by dilution or neutralization to lower the pH, where Na... + The strength is minimized, thus inducing particle-particle interactions (intramolecular hydrogen bonding). Washing of the hydrogel completely removes Na. + This leads to the recombination of OH groups (intramolecular interactions), resulting in a more stable solid structure. Ice crystals on the surface and within the structure of the cryogel sublimate through freeze-drying, creating open pores and mesopores, respectively.

[0241] The gelation process is enhanced by the introduction of foreign particles (hybrid materials) due to intermolecular hydrogen bonding. Mg in α-1,3-glucan solution (with excess NaOH) + Ca + The presence of Ti((OH)3OCH(CH3)2)4 leads to an ion exchange process. In this medium, Na + With Cl - (Present when using magnesium chloride or calcium chloride) or (OH)3OCH(CH3)2 anion reaction, and Mg 2+ Ca 2+ or Ti 4+ Na replaces oxygen attached to C2, C4, and C6 + When the pH decreases, an enhanced structure is obtained due to the elimination of some NaOH substances. However, due to Ca... 2+ Mg 2+ and Ti 4+ Its divalent and tetravalent properties mean that it may coordinate differently with the α-1,3-glucan structure. 2+ and Mg 2+ and Ti 4+ The hydrogen atoms form two-point and four-point coordinations with the dextran structure, respectively, resulting in the formation of MgO, CaO, and TiO2 on the α-1,3-glucan structure. Due to intermolecular hydrogens, OH stretching and weakened CO and COC interactions (intramolecular interactions) of the α-1,3-glucan structure were observed in the hybrid samples (FTIR and XPS results). TiO2 generates multivalent hydrogen bonds, which improves surface area, pore volume, and structural integrity.

[0242] in conclusion:This work demonstrates the preparation of hydrophilic, microporous, and self-supporting α-1,3-glucan-based aerogels with superabsorbent properties. Aerogels with controlled properties were prepared using a co-precipitation method combined with freeze-drying. Specifically, the co-precipitation method enabled the production of hybrid MgO / glucan, CaO / glucan, and TiO2 / glucan aerogels, which were found to be excellent for human hygiene applications. Detailed characterization of the aerogels revealed that the functional groups (OH, CO, COC, COH, and CC) of α-1,3-glucan were successfully modulated upon in-situ introduction of MgO, CaO, or TiO2 due to the formation of intermolecular hydrogen bonds. Using two different adsorption techniques, unloaded and loaded, and three different model fluids (DI water as baseline, saline as urine, and glycerol / water solution as menstrual discharge), the hybrid dextran aerogels were demonstrated to be suitable as absorbents in human hygiene products. Compared to pure α-1,3-glucan aerogels, the hybrid dextran aerogels exhibited improved fluid absorption performance. Among hybrid dextran aerogels, the TiO2 / dextran aerogel exhibited the largest fluid absorption capacity in all the above absorption demonstrations. This performance is attributed to the superior structural network and integrity, surface area, pore volume, and smaller pore size resulting from the efficient intermolecular hydrogen bonding between TiO2 and α-1,3-dextran. It is also noteworthy that, in liquid models of urine and menstrual fluid, the absorption performance of the hybrid dextran aerogel generally outperformed that of commercial superabsorbents.

[0243] Auxiliary Examples

[0244] Formulations were developed and used to prepare molded microporous foams containing at least polyurethane and α-1,3-glucan. Such molded foams can be used, for example, in applications such as footwear (e.g., insoles) or other applications employing cushioning materials. Foams are prepared using the materials listed in Table 1 and following the standards listed in Tables 2-3.

[0245]

[0246]

[0247]

[0248] Evaluate the various properties of the prepared foam (Table 4).

[0249]

[0250]

[0251] Additional molded foams were prepared to examine the effects of (i) SUSTERRA (propylene glycol) alone or (ii) a combination of SUSTERRA and NUVOLVE (α-1,3-glucan) as the bio-derived component of the prepared foams. Specifically, the foam product INSITE ECOCOMFORT TERRAIN F71 contained approximately 50 wt% SUSTERRA, while the foam product INSITE ECOCOMFORT TERRAIN IF99 contained approximately 45 wt% SUSTERRA and approximately 5 wt% NUVOLVE. Both F71 and IF99 products contained approximately 50 wt% gasoline-based diisocyanate polyurethane. The properties of these molded foams are listed in Table 6.

[0252]

Claims

1. A composition comprising an aerogel, wherein the aerogel comprises a water-insoluble α-glucan and a metal oxide, wherein at least about 50% of the glycosidic bonds of the insoluble α-glucan are α-1,3 bonds, and wherein the metal oxide is calcium oxide (CaO), magnesium oxide (MgO), or titanium dioxide (TiO2).

2. The composition of claim 1, wherein, At least about 90% of the glycosidic bonds in the water-insoluble α-glucan are α-1,3 glycosidic bonds.

3. The composition of claim 1, wherein, The water-insoluble α-glucan has a weight-average degree of polymerization (DPw) of at least about 10.

4. The composition of claim 3, wherein, The DPw is at least about 400.

5. The composition of claim 1, wherein, The metal oxide is titanium dioxide (TiO2).

6. The composition of claim 1, wherein, The aerogel contains less than about 20 wt% of the metal oxide, optionally wherein the balance by mass of the aerogel is the water-insoluble α-glucan.

7. The composition of claim 1, wherein, The metal oxide interacts with the water-insoluble α-glucan via hydrogen bonding.

8. The composition of claim 1, wherein, The aerogel has been crushed.

9. The composition of claim 1, wherein, The aerogel further comprises water or an aqueous liquid, typically wherein the water or aqueous liquid is absorbed by the aerogel, and optionally wherein the aerogel is under a load.

10. The composition of claim 1, wherein, The composition is a personal care product, a home care product, a medical product, a pharmaceutical product, or an industrial product, and / or the composition is an absorbent product.

11. An aqueous caustic alkali solution comprising (i) an aqueous caustic alkali solvent, (ii) a water-insoluble α-glucan, and (iii) a metal hydroxide. The water-insoluble α-glucan wherein at least about 50% of the glycosidic bonds are α-1,3 glycosidic bonds. The water-insoluble α-glucan is soluble in the aqueous caustic solvent and the metal hydroxide is insoluble in the aqueous caustic solvent. The metal hydroxide mentioned therein is calcium hydroxide, magnesium hydroxide, or titanium hydroxide.

12. The aqueous caustic alkali solution as described in claim 11, wherein, At least about 90% of the glycosidic bonds in the water-insoluble α-glucan are α-1,3 glycosidic bonds.

13. The aqueous caustic alkali solution as described in claim 11, wherein, The water-insoluble α-glucan has a weight-average degree of polymerization (DPw) of at least about 10.

14. The aqueous caustic alkali solution as described in claim 11, wherein, Aqueous caustic solvents contain at least one basic hydroxide.

15. A method for producing an aerogel, the method comprising: (a) Providing the aqueous caustic alkali solution as described in claim 11, (b) To convert the aqueous caustic alkali solution into the desired form. (c) Chemically or ionicly modifying the aqueous caustic solvent such that the water-insoluble α-glucan and the metal hydroxide are insoluble in the solvent, thereby producing a hydrogel, and (d) Remove all or most of the water from the hydrogel, thereby producing an aerogel.

16. The method of claim 15, wherein, Step (a) includes combining a salt of the metal hydroxide with an aqueous caustic alkali solution in which the water-insoluble α-glucan is dissolved, typically wherein the salt is provided in the form of a solution dissolved in an aqueous solution, and the metal hydroxide precipitates from the solution when combined with the aqueous caustic alkali solution.

17. The method of claim 15, wherein, Step (c) includes lowering the pH of the caustic alkali solution to a pH that makes the water-insoluble α-glucan insoluble in the solvent.

18. The method of claim 15, wherein, Step (c) further includes keeping the solution stationary during the formation of the hydrogel.

19. The method of claim 15, wherein, Step (d) includes freeze-drying or supercritical drying of the hydrogel to form the aerogel.

20. An absorption method comprising contacting the composition of claim 1 with a composition comprising an aqueous liquid, wherein the composition absorbs the aqueous liquid from the composition comprising the aqueous liquid.

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