Improved aerogel composition and method

Abstract

The present disclosure produces aerogel compositions that are inherently hydrophobic without surface modification with a hydrophobizing agent, are durable, easy to handle, perform well in aqueous environments, and also have good combustion and self-heating properties. Methods for preparing aerogel compositions that are inherently hydrophobic without surface modification with a hydrophobizing agent, are durable, easy to handle, perform well in aqueous environments, and also have good combustion and self-heating properties are also provided.

Description

Cross-reference of related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 006,003, filed on April 6, 2020, and U.S. Patent Application Publication No. 17 / 223,043, each of which is incorporated herein by reference in whole and governs the definitions of any of the terms used herein. [Technical Field]

[0002] The present invention generally relates to aerogel technology. More specifically, the present invention relates, in various embodiments, to improved methods for producing aerogels and improved aerogel compositions. [Background technology]

[0003] Low-density aerogel materials are widely considered to be the best available solid insulators. Aerogels function as insulators primarily by minimizing conduction (low structural density results in winding pathways for energy transfer through the solid framework), convection (large pore volume and very small pore diameter minimize convection), and radiation (IR absorption or scattering dopants are easily dispersed throughout the aerogel substrate). Aerogels can be used in a wide range of applications, including thermal and cooling insulation, acoustic insulation, electronic dielectrics, aerospace, energy storage and production, and filtration. Furthermore, aerogel materials exhibit many other interesting acoustic, optical, mechanical, and chemical properties that make them highly useful in a variety of insulating and non-insulating applications.

[0004] While certain aspects of the prior art have been discussed to facilitate the disclosure of the present invention, the applicant does not in any way negate these technical aspects, and the claimed invention is intended to encompass one or more of the prior art aspects described herein.

[0005] The present disclosure can address one or more of the problems and drawbacks of the prior art. However, it is contemplated that the embodiments disclosed herein may be found useful in addressing other problems and deficiencies in several technical fields. Accordingly, the claimed invention should not be construed as necessarily limited to addressing any of the specific problems or deficiencies discussed herein.

[0006] In this specification, when a document, act or item of knowledge is referenced or discussed, this reference or discussion does not admit that the document, act or item of knowledge or any combination thereof was available as of the priority date, publicly available, known to the public, part of common general knowledge or otherwise constituted prior art under the applicable statutory provisions. Nor does it admit that it is known to be relevant to any attempt to solve any problem with which this specification is concerned.

Summary of the Invention

[0007] The long-standing but heretofore unmet need for improved aerogel compositions is met by the present novel, useful and non-obvious invention. In one general aspect, the present disclosure can produce an aerogel composition that is durable, easy to handle, has good performance in an aqueous environment, and also has good combustion and self-heating properties. In certain embodiments, the present disclosure presents an aerogel composition that is a flexible, elastic and self-standing reinforced aerogel composition having good performance in an aqueous environment and also having good combustion and self-heating properties.

[0008] The first general aspect relates to a composition comprising a silica-based aerogel. In an exemplary embodiment, the silica-based aerogel comprises hydrophobic bonded silicon, and more than 50% of the hydrophobic bonded silicon is bonded to one or fewer alkyl groups. For example, in a preferred embodiment, the silica-based aerogel is not surface-treated with a hydrophobizing agent.

[0009] A second general embodiment relates to a composition comprising an essentially hydrophobic silica-based aerogel. In an exemplary embodiment, the composition has a heat of combustion of less than 717 cal / g. In an exemplary embodiment, the silica-based aerogel has surface groups, which essentially consist of hydrophobic groups of the formula Si-R, where R is a single methyl group.

[0010] A third general embodiment relates to a composition comprising a silica-based aerogel, comprising at least about 0.1% by weight of a strong base or a strong base derivative. For example, the composition may contain up to about 2% by weight of a strong base or a strong base derivative. The strong base or strong base derivative may contain a cation selected from the group consisting of lithium, calcium, sodium, potassium, rubidium, barium, strontium, and guanidinium. In an exemplary embodiment, the silica-based aerogel comprises hydrophobic-bonded silicon, with more than 50% of the hydrophobic-bonded silicon bonded to a single alkyl group. In an exemplary embodiment, the composition has a water absorption rate in the range of about 15% by weight or less, a heat of combustion of less than 717 cal / g, and an initiation of thermal decomposition of the hydrophobic organic material at 400°C or higher.

[0011] In exemplary embodiments, the composition has a water absorption rate in the range of about 5% by weight or less, 3% by weight or less, 2% by weight or less, or about 1% by weight or less. In some embodiments, the composition has a heat of combustion of less than 717 cal / g. For example, the composition may have a heat of combustion in the range of about 700 cal / g or less, about 650 cal / g or less, about 600 cal / g or less, about 575 cal / g or less, about 550 cal / g or less, about 500 cal / g or less, about 450 cal / g or less, about 400 cal / g or less, about 350 cal / g or less, about 300 cal / g or less, about 250 cal / g or less, about 200 cal / g or less, about 150 cal / g or less, about 100 cal / g or less, about 50 cal / g or less, about 25 cal / g or less, or about 10 cal / g or less. In exemplary embodiments, the composition has a heat of combustion from 250 cal / g to 600 cal / g.

[0012] In exemplary embodiments, the composition may have the initiation of thermal decomposition of a hydrophobic organic material at 350°C or higher. For example, the composition may have the initiation of thermal decomposition of a hydrophobic organic material at 400°C or higher, or at 500°C or higher.

[0013] In exemplary embodiments, the silica-based aerogel may have an ammonium salt content in the range of about 2000 ppm or less. For example, the silica-based aerogel may have an ammonium salt content in the range of about 1000 ppm or less, 500 ppm or less, 200 ppm or less, or 100 ppm or less.

[0014] In exemplary embodiments, the silica-based aerogel may have an ammonium salt content in the range of about 0.2% by weight or less. For example, the silica-based aerogel may have an ammonium salt content in the range of about 0.1% by weight or less. In some embodiments, the silica-based aerogel has a water absorption rate in the range of about 10% by weight or less, about 8% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, or about 0.1% by weight or less.

[0015] In exemplary embodiments, the silica-based aerogel has a thermal conductivity of less than about 45 mW / M*K. For example, the silica-based aerogel may have a thermal conductivity of about 45 mW / M*K or less, about 40 mW / M*K or less, about 35 mW / M*K or less, about 30 mW / M*K or less, about 25 mW / M*K or less, about 20 mW / M*K or less, about 18 mW / M*K or less, about 16 mW / M*K or less, about 15 mW / M*K or less, about 14 mW / M*K or less, about 13 mW / M*K or less, about 12 mW / M*K or less, or in the range of about 5 mW / M*K to 50 mW / M*K.

[0016] In exemplary embodiments, the composition may further include reinforcing materials. For example, the reinforcing materials may include fiber reinforcing materials or foam reinforcing materials.

[0017] In exemplary embodiments, the composition may include opacifying or fire-class additives. For example, the opacifying or fire-class additive may be present in an amount ranging from about 0.1% to about 10% by weight relative to the silica content of the aerogel. For example, the opacifying or fire-class additive may be present in an amount ranging from 0.5% to about 3.0% by weight relative to the silica content of the aerogel. The opacifying or fire-class additives include boron carbide, diatomaceous earth, manganese ferrite, manganese oxide, nickel oxide, tin oxide, silver oxide, bismuth oxide, titanium carbide, tungsten carbide, carbon black, titanium oxide, iron oxide, zirconium silicate, zirconium oxide, iron oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, iron oxide (ilmenite), chromium oxide, silicon carbide, phyllosilicate clay, kaolin or kaolinite (aluminum silicate, Al2S i2O5(OH)4), metakaolin, halloysite (aluminum silicate, Al2Si2O5(OH)4), metahaloysite, endelite (aluminum silicate, Al2Si2O5(OH)4), mica (silica mineral), diaspore (aluminum oxide hydroxide, α-AlO(OH)), gibbsite (aluminum hydroxide), boehmite (aluminum oxide hydroxide, γ-AlO(OH)), montmorillonite, beidelite, pyrophyllite (aluminum silicate, Al2Si4O 10 (OH)2) Nontronite, Brabisite, Smectite, Re B Lierite, rectolite, celadonite, attapulgite, chloroparl, volconscite, allo Fen , racwinite, dillnite, severite, milo SkaThe additives may be selected from litholite, corylite, simolite and newtonite, sodium bicarbonate (NaHCO3), magnesium hydroxide (or magnesium dihydrate), alumina trihydrate, gypsum (calcium sulfate dihydrate, CaSO4·2H2O), valintonite (MgCO3·2H2O), neskehonite (MgCO3·3H2O), lancefoldite (MgCO3·5H2O), hydromagnesite (hydrated magnesium carbonate, Mg5(CO3)4(OH)2·4H2O), dolomite, lithium carbonate, or combinations and mixtures thereof. In certain embodiments, the additive may include, for example, silicon carbide in the above reference range for the silica content of the aerogel. In certain embodiments, the additive may include, for example, metakaolin in the above reference range for the silica content of the aerogel.

[0018] In exemplary embodiments, the composition may further contain at least about 0.1% by weight of a strong base or strong base derivative. For example, the composition may contain up to about 2% by weight of a strong base or strong base derivative. The strong base or strong base derivative may contain a cation selected from the group consisting of lithium, calcium, sodium, potassium, rubidium, barium, strontium, and guanidinium.

[0019] A further general embodiment is a method comprising: preparing a precursor solution containing silica gel precursor material and a solvent; preparing a basic catalyst solution having less than about 4 pKb; combining the precursor solution and the basic catalyst solution; transferring the silica precursor material to a gel composition; and extracting at least a portion of the solvent from the gel composition to obtain a silica-based aerogel composition.

[0020] In exemplary embodiments, the precursor solution comprises at least one silica gel precursor material having at least one hydrophobic group. For example, the precursor solution may contain more than 30% of at least one silica gel precursor material having a single alkyl group bonded to silicon. In further examples, the precursor solution may contain more than 30% of at least one silica gel precursor material having a single methyl group bonded to silicon. In any embodiment, the gel composition is not surface-treated with a hydrophobic agent. In another example, the basic catalyst used to catalyze the precursor reaction may contain a catalytic amount of a strong base selected from the group consisting of sodium hydroxide, lithium hydroxide, calcium hydroxide, potassium hydroxide, strontium hydroxide, barium hydroxide, guanidine hydroxide, sodium hydroxide, tetrabutylammonium hydroxide, tetramethylammonium hydroxide, choline hydroxide, phosphonium hydroxide, DABCO, DBU, guanidine derivatives, amidine, and phosphazene.

[0021] In exemplary embodiments, the method may include incorporating a reinforcing material into a silica-based aerogel composition. The method may also include incorporating an additive into a silica-based aerogel composition. In exemplary embodiments, the additive may be present in an amount ranging from about 0.1% to about 10% by weight relative to the silica content of the aerogel. For example, the additive may be present in an amount ranging from about 0.5% to about 3% by weight relative to the silica content of the aerogel. Examples of additives include boron carbide, diatomaceous earth, manganese ferrite, manganese oxide, nickel oxide, tin oxide, silver oxide, bismuth oxide, titanium carbide, tungsten carbide, carbon black, titanium oxide, iron oxide, zirconium silicate, zirconium oxide, iron oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, iron oxide (ilmenite), chromium oxide, silicon carbide, phyllosilicate clay, kaolin, or kaolinite (aluminum silicate, Al2Si2O5(OH)) 4) Metakaolin, halloysite (aluminum silicate, Al2Si2O5(OH)4), metahaloysite, endelite (aluminum silicate, Al2Si2O5(OH)4), mica (silica mineral), diaspore (aluminum hydroxide oxide, α-AlO(OH)), gibbsite (aluminum hydroxide), boehmite (aluminum hydroxide oxide, γ-AlO(OH)), montmorillonite, beidelite, pyrophyllite (aluminum silicate, Al2Si4O 10 (OH)2) Nontronite, Brabisite, Smectite, Re B Lierite, rectolite, celadonite, attapulgite, chloroparl, volconscite, allo Fen , racwinite, dillnite, severite, milo SkaThe additives may be selected from litholite, corylite, simolite and newtonite, sodium bicarbonate (NaHCO3), magnesium hydroxide (or magnesium dihydrate), alumina trihydrate, gypsum (calcium sulfate dihydrate, CaSO4·2H2O), valintonite (MgCO3·2H2O), neskehonite (MgCO3·3H2O), lancefoldite (MgCO3·5H2O), hydromagnesite (hydrated magnesium carbonate, Mg5(CO3)4(OH)2·4H2O), dolomite, lithium carbonate, or combinations and mixtures thereof. In certain embodiments, the additive may include, for example, silicon carbide in the above reference range for the silica content of the aerogel. In certain embodiments, the additive may include, for example, metakaolin in the above reference range for the silica content of the aerogel. [Brief explanation of the drawing]

[0022] To understand the present invention more completely, refer to the following detailed description in relation to the accompanying drawings.

[0023] [Figure 1] This graph shows the TGA / DSC analysis of an exemplary aerogel composition of this disclosure. [Modes for carrying out the invention]

[0024] The following detailed description of preferred embodiments will refer to the accompanying drawings illustrating specific embodiments that form part of the present invention and can be used to carry it out. It should be understood that other embodiments may be utilized and structural modifications may be made without departing from the scope of the present invention.

[0025] As used herein and in the appended claims, the singular forms “a,” “an,” and “the” refer to multiple subjects unless the content clearly indicates otherwise. As used herein and in the appended claims, the term “or” is generally used to mean “and / or” unless the context otherwise explicitly indicates otherwise.

[0026] As used herein, “about” means roughly or approximately in the context in which it is presented. In embodiments, the term “about” may include conventional rounding by significant figures of a number. Also, “about 'x' to 'y'” includes “about 'x' to about 'y'.”

[0027] As used herein, the terms “composition” and “complex” are interchangeable.

[0028] Aerogels are a class of porous materials having an interconnected structural framework, a corresponding network of pores incorporated within the framework, and an open-cell structure containing interstitial phases within the network of pores, primarily composed of gases such as air. Aerogels are typically characterized by low density, high porosity, large surface area, and small pore size. Aerogels can be distinguished from other porous materials by their physical and structural properties.

[0029] In the context of this disclosure, the terms “aerogel” or “aerogel material” refer to a gel that includes an interconnected structural framework, in which a corresponding network of interconnected pores is incorporated within the framework, and which contains a gas such as air as a dispersed interstitial medium, and which have the following characteristics due to aerogel: (a) an average pore size ranging from about 2 nm to about 100 nm, (b) a porosity of at least 80%, and (c) about 20 nm 2 It is characterized by physical and structural properties (determined by nitrogen porosimetry testing) such as a surface area of ​​1 / g or more.

[0030] Accordingly, the aerogel materials of this disclosure include any aerogel or other open-cell compound that satisfies the clarification elements described in the preceding paragraph, and also include compounds that can be classified as xerogels, cryogels, ambigels, microporous materials, etc.

[0031] Aerogel materials may also be further characterized by additional physical properties including (d) a pore volume of about 2.0 mL / g or more, preferably about 3.0 mL / g or more, (e) a density of about 0.50 g / cc or less, preferably about 0.25 g / cc or less, and (f) at least 50% of the total pore volume including pores having a pore diameter between 2 and 50 nm; however, characterization of a compound as an aerogel material is not required to satisfy these additional properties.

[0032] In the context of this disclosure, the term “innovative processing and extraction techniques” refers to methods of replacing the liquid interstitial phase of a wet gel material with a gas such as air to induce low pore collapse and low shrinkage of the gel's skeletal structure. Drying techniques, such as ambient pressure evaporation, often introduce strong capillary pressure and other mass transfer limitations at the liquid-vapor interface of the interstitial phase being evaporated or removed. The strong capillary forces resulting from the evaporation or removal of the liquid can cause significant pore shrinkage and skeletal collapse within the gel material. Using innovative processing and extraction techniques during the extraction of the liquid interstitial phase reduces the adverse effects of capillary forces on pores and the gel's skeletal structure during the extraction of the liquid phase.

[0033] In certain embodiments, innovative processing and extraction techniques utilize near-critical or supercritical fluids, or near-critical or supercritical conditions, to extract the liquid interstitial phase from a wet gel material. This can be achieved by removing the liquid interstitial phase from the gel near or above the critical point of the liquid or mixture of liquids. Co-solvents and solvent exchange can be used to optimize the near-critical or supercritical fluid extraction process.

[0034] In certain embodiments, innovative processing and extraction techniques include modifications to the gel skeleton to reduce the irreversible effects of capillary pressure and other mass transfer limits at the liquid-vapor interface. This embodiment may include treatment of the gel skeleton with a functionalizing agent during liquid-phase extraction performed below the critical point of the liquid interplasmic phase, which enables the gel skeleton to withstand or recover from any collapsing force. This embodiment may also include the incorporation of functional groups or elements of the skeleton that impart a sufficiently high modulus of elasticity to the gel skeleton to withstand or recover from any collapsing force during liquid-phase extraction performed below the critical point of the liquid interplasmic phase.

[0035] In the context of this disclosure, the term “skeleton” or “skeleton structure” refers to a network of interconnected oligomers, polymers, or colloidal particles that form a solid structure in a gel or aerogel. The polymers or particles constituting the skeleton structure typically have a diameter of about 100 angstroms. However, the skeleton structure in this disclosure may also include a network of interconnected oligomers, polymers, or colloidal particles of all diameter sizes that form a solid structure within the gel or aerogel. Furthermore, the term “silica-based aerogel” or “silica-based skeleton” refers to an aerogel skeleton containing at least 50 (by weight) silica in the oligomers, polymers, or colloidal particles that form a solid skeletal structure within the gel or aerogel.

[0036] In the context of this disclosure, the term “aerogel composition” refers to any composite material that includes an aerogel material as a component of the composite material. Examples of aerogel compositions include, but are not limited to, fiber-reinforced aerogel composites, aerogel composites containing additive elements such as opacifiers, aerogel foam composites, aerogel-polymer composites, and composites incorporating aerogel microparticles, particles, granules, beads, or powders into a solid or semi-solid material such as a binder, resin, cement, foam, polymer, or similar solid material. Aerogel compositions are generally obtained after removing the solvent from the various gel materials disclosed in this invention. The aerogel compositions thus obtained may be subjected to further additional processing or treatment. The various gel materials may also be subjected to additional processing or treatments that are otherwise known or useful in the art before being subjected to solvent removal (or liquid extraction or drying).

[0037] In the context of this invention, the term “monolithic” refers to an aerogel material in which the majority (by weight) of the aerogel contained in the aerogel material or composition is in the form of a single interconnected aerogel nanostructure. Monolithic aerogel materials include aerogel materials that are initially formed to have a single interconnected gel or aerogel nanostructure but are subsequently cracked, fractured, or divided into non-integrated aerogel nanostructures. Monolithic aerogel materials are distinguished from granular aerogel materials. The term “granular aerogel material” refers to an aerogel material in which the majority (by weight) of the aerogel contained in the aerogel material is in the form of fine particles, particles, granules, beads, or powders, which can be bound together or compressed but lack interconnected aerogel nanostructures between the individual particles.

[0038] The aerogel compositions of this disclosure may include reinforced aerogel compositions. In the context of this disclosure, the term “reinforced aerogel composition” means an aerogel composition that includes a reinforcing phase within the aerogel material, which is not part of the aerogel skeleton. The reinforcing phase may be any material that gives the aerogel material high flexibility, elasticity, conformability, or structural stability. Examples of well known reinforcing materials include, but are not limited to, open-cell microporous foam reinforcing materials, closed-cell microporous foam reinforcing materials, open-cell membranes, honeycomb reinforcing materials, polymer reinforcing materials, and fiber reinforcing materials such as discrete fibers, woven fabrics, nonwoven fabrics, battings, webs, mats, and felts. Furthermore, fiber-based reinforcing materials may be combined with one or more other reinforcing materials and may be continuously oriented in the whole or limited preferred portion of the composition.

[0039] In the context of this disclosure, the term “fiber-reinforced aerogel composition” refers to a reinforced aerogel composition comprising a fiber-reinforced material as a reinforcing phase. Examples of fiber-reinforced materials include, but are not limited to, discrete fibers, woven materials, nonwoven materials, battings, webs, mats, felts, or combinations thereof. Fiber-reinforced materials include polyester, polyolefin terephthalate, poly(ethylene) naphthalate, polycarbonate (e.g., rayon, nylon), cotton (e.g., Lycra from DuPont), carbon (e.g., graphite), polyacrylonitrile (PAN), oxidized PAN, non-carbonized heat-treated PAN (e.g., from SGL carbon), fiberglass-based materials (such as S glass, 901 glass, 902 glass, 475 glass, E glass), quartz-like silica-based fibers (e.g., quartz glass from Saint-Gobain), Q felt (from Johns Manville), Saphir (from Saphir), DuraBlanket (Uniflax) and other silica fibers, DuraVac (Carborundum), polyaramid fibers such as Kevlar, Nomex, Zontera (all DuPont), Conex (Tydin), polyolefins such as Tibek (DuPont), Dyneema (DSM), Spectra (Honeywell), other polypropylene fibers such as Typar, Xavan (both DuPont), fluorinated polymers such as Teflon (DuPont) and PTFE under the trade name Goretex (WLGORE), Nicalon (COI This includes a wide variety of materials, including but not limited to silicon carbide fibers (such as Ceramics), ceramic fibers (such as Nextel from 3M), acrylic polymers, wool fibers, silk, hemp, leather, suede, liquid crystal materials such as PBO-Zylon fibers (Tyobo), Vectan (Hoechst), Cambrelle fibers (DuPont), polyurethane, polyamide, wood fibers, boron, aluminum, iron, stainless steel fibers, and thermoplastic resins such as PEEK, PES, PEI, PEK, and PPS.

[0040] The reinforced aerogel compositions of the present disclosure may include aerogel compositions reinforced with open-cell macroporous framework materials. In the context of the present disclosure, the terms “open-cell macroporous framework” or “OCMF” refer to a porous material comprising a framework of interconnected structures of substantially uniform composition, in which a corresponding network of interconnected pores is incorporated within the framework, characterized by an average pore diameter ranging from about 10 μm to about 700 μm. Such an average pore diameter may be measured by known techniques, including but not limited to microscopy using optical analysis. Accordingly, the OCMF materials of the present disclosure include any open-cell materials that satisfy the elements defined in this paragraph, including compounds that could otherwise be classified as foams, foam-like materials, macroporous materials, etc. OCMF materials can be distinguished from materials comprising a framework of interconnected structures that have void volumes within the framework and do not have a uniform composition, such as an assembly of fibers and binders having void volumes within a fiber matrix.

[0041] In the context of this disclosure, the term “substantially uniform composition” refers to the uniformity of the composition of the referred material within a 10% tolerance.

[0042] In the context of this disclosure, the term “OCMF-reinforced aerogel composition” refers to a reinforced aerogel composition comprising an open-cell macroporous skeletal material as a reinforcing phase. Suitable OCMF materials for use in this disclosure include, but are not limited to, OCMF materials made from organic polymer materials. Examples include OCMF materials made from polyolefins, polyurethanes, phenols, melamines, cellulose acetates, and polystyrenes. In the context of this disclosure, the term “organic OCMF” refers primarily to OCMF materials having a skeletal structure composed of organic polymer materials. In certain embodiments, OCMF materials made from melamine or melamine derivatives are also preferred. In the context of this disclosure, the term “melamine OCMF” or “melamine-based OCMF” refers to organic OCMF materials having a skeletal structure primarily composed of polymer materials derived from the reaction of melamine with a condensing agent such as formaldehyde. Examples of OCMF materials manufactured from melamine or melamine derivatives for use in this disclosure are presented in U.S. Patent No. 8,546,457, U.S. Patent No. 4,666,948, and International Publication No. 2001 / 094436. The term "inorganic OCMF" refers to OCMF materials having a framework primarily composed of inorganic materials. Examples of inorganic OCMF include, but are not limited to, cementitious materials, gypsum, and calcium silicate.

[0043] In the context of the present invention, the term “foam” refers to a material formed by dispersing a certain proportion of gas in the form of bubbles into a liquid or resin foam material, such that it comprises a framework of interconnected polymer structures of substantially uniform composition, with corresponding networks or pore aggregates incorporated within the framework, and the bubbles are retained as pores as the foam material solidifies into a solid structure. Generally, foams can be manufactured using a wide variety of processes; see, for example, U.S. Patent Nos. 6,147,134, 5,889,071, 6,187,831, and 5,229,429. Accordingly, the foam materials of this disclosure include any material that satisfies the elements defined in this paragraph, including compounds that could otherwise be classified as OCMF materials, macroporous materials, etc. The foams as defined in the present invention may be of the types of thermoplastic resins, elastomers, and thermosetting resins (duromers).

[0044] Pores within a solid framework can also be called “bubbles.” Bubbles can be separated by a wall or membrane, creating a collection of independent closed pores within a porous material. The term “closed-cell” refers to a porous material in which at least 50% of the pore volume is enclosed by a membrane or wall, and is [substantially] closed-cell. Bubbles in a material can also be interconnected through their openings, forming a network of interconnected open pores within the material. The term “open-cell” refers to a porous material in which at least 50% of the pore volume is open-cell. Open-cell materials can include reticular open-cell materials, non-reticular open-cell materials, or a combination thereof. Reticular materials are open-cell materials produced by a reticularization process that eliminates or punctures the membranes of bubbles within the porous material. Reticular materials typically have a higher concentration of open-cells than non-reticular materials, but tend to be more expensive and difficult to manufacture. In general, porous materials do not have a completely single type of cellular structure (either open-cell or closed-cell). Porous materials can be manufactured using a wide variety of processes, including foam manufacturing processes as presented in U.S. Patent Nos. 6,147,134, 5,889,071, 6,187,831, 5,229,429, 4,454,248, and U.S. Patent Publication No. 2007 / 0213417.

[0045] In the context of this disclosure, the terms “aerogel blanket” or “aerogel blanket composition” refer to an aerogel composition reinforced with a continuous sheet of reinforcing material. Aerogel blanket compositions can be distinguished from other reinforced aerogel compositions reinforced with discontinuous networks of fibers or foams, such as separated aggregates or clumps of fibrous material. Aerogel blanket compositions are highly adaptable and can be used like a blanket to cover surfaces of simple or complex geometric shapes while retaining the excellent thermal insulation properties of aerogel, making them particularly useful in applications requiring flexibility.

[0046] In the context of this disclosure, the term “wet gel” refers to a gel in which the mobile pore phase within an interconnected network of pores is primarily composed of a liquid phase such as a conventional solvent, a liquefied gas such as liquid carbon dioxide, or a combination thereof. Aerogels typically require the initial generation of a wet gel and subsequent innovative processing and extraction to replace the mobile pore liquid phase of the gel with air. Examples of wet gels include, but are not limited to, alcohol gels, hydrogels, ketogels, carbonogels, and any other wet gels known to those skilled in the art.

[0047] In the context of this disclosure, the terms “additive” or “additive element” refer to materials that may be added to an aerogel composition before, during, or after the manufacture of an aerogel. Additives may be added to alter or improve desirable properties of the aerogel, or to counteract undesirable properties in the aerogel. Additives are typically added to the aerogel material before or during gelation. Examples of additives include, but are not limited to, microfibers, fillers, reinforcing agents, stabilizers, thickeners, elastic compounds, opacifiers, coloring or pigmenting compounds, radiation-absorbing compounds, radiation-reflecting compounds, corrosion inhibitors, thermally conductive components, phase change materials, pH adjusters, redox adjusters, HCN mitigators, off-gas mitigators, conductive compounds, dielectric compounds, magnetic compounds, radar-blocking components, curing agents, shrinkage inhibitors, and other aerogel additives known to those skilled in the art. Other examples of additives include smoke suppressants and fire suppressants. The published U.S. Patent Application Publication No. 2007 / 0272902 (paragraphs

[0008] and

[0010] to

[0039] ) contains teachings on smoke suppressants and fire suppressants, which are incorporated herein by reference in accordance with the paragraphs cited individually.

[0048] In the context of this disclosure, the terms “flexible” and “flexible” refer to an aerogel material or composition that can be bent or flexed without macrostructural fracture. Preferably, the aerogel compositions of this disclosure can be bent at least 5°, at least 25°, at least 45°, at least 65°, or at least 85° without macroscopic fracture, and / or have a bending radius of less than 4 feet, less than 2 feet, less than 1 foot, less than 6 inches, less than 3 inches, less than 2 inches, less than 1 inch, or less than 1 / 2 inch without macroscopic fracture. Similarly, the terms “highly flexible” or “highly flexible” refer to an aerogel material or composition that can be bent up to at least 90° without macroscopic fracture, and / or have a bending radius of less than 1 / 2 inch. Furthermore, the terms “classified as flexible” and “classified as flexible” refer to an aerogel material or composition that can be classified as flexible according to ASTM classification standard C1101 (ASTM International, West Conshohocken, Pennsylvania).

[0049] The aerogel materials or compositions of this disclosure may be classified as flexible, highly flexible, and / or pliable. The aerogel materials or compositions of this disclosure may also be drapeable. In the context of this disclosure, the terms “drape” and “drapeable” mean that the aerogel material or composition can be bent or flexed by 90° or more with a radius of curvature of about 4 inches or less without macroscopic fracture. The aerogel materials or compositions of this disclosure may preferably be non-rigid and flexible so that the composition can be applied to and adapted to a three-dimensional surface or three-dimensional object, or may be pre-formed into various shapes and configurations to simplify installation or application.

[0050] In the context of this disclosure, the terms “elastic” and “flexible” mean that an aerogel material or composition can return to its original shape or dimensions at least partially after deformation by compression, bending, or flexing. Elasticity may be full or partial, and may be expressed in terms of the percentage of return. The aerogel materials or compositions of this disclosure preferably have an elasticity of more than 25%, more than 50%, more than 60%, more than 70%, more than 75%, more than 80%, more than 85%, more than 90%, or more than 95% that returns to its original shape or dimensions after deformation. Similarly, the terms “classified as elastic” and “classified as elastic” mean the aerogel materials or compositions of this disclosure that can be classified as elastically flexible according to ASTM C1101 (ASTM International, West Conshohocken, Pennsylvania).

[0051] In the context of this disclosure, the term “self-supporting” refers primarily to the ability of an aerogel material or composition to be flexible and / or elastic, based on the physical properties of the aerogel and any reinforcing phase in the aerogel composition. The self-supporting aerogel materials or compositions of this disclosure can be distinguished from other aerogel materials, such as coatings, which depend on an underlying substrate to impart flexibility and / or elasticity to the material.

[0052] In the context of this disclosure, the term “shrinkage rate” means 1) the ratio of the measured final density of the dry aerogel material or composition to the target density calculated from the solid content in the sol-gel precursor solution, and 2) the ratio of the target density calculated from the solid content in the sol-gel precursor solution. The shrinkage rate is given by the following formula: Shrinkage rate = [Final density (g / cm³)] 3 )-Target density (g / cm³) 3 )] / [Target density (g / cm³) 3 It can be calculated as follows: Preferably, the shrinkage rate of the aerogel material of this disclosure is 50% or less, 25% or less, 10% or less, 8% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, 0.1% or less, about 0.01% or less, or in the range of any two of these values.

[0053] In the context of this disclosure, the terms “thermal conductivity” and “TC” refer to a measure of a material or composition’s ability to transfer heat between two surfaces, where there is a temperature difference between the two surfaces. Thermal conductivity is specifically measured as the thermal energy transferred per unit time and per unit surface area divided by the temperature difference. This is typically recorded in SI units as mW / *K (milliwatts per meter * Kelvin).The thermal conductivity of materials is not limited to these, but can be determined using the following methods: Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus (ASTM C518, ASTM International, West Conshohocken, Pennsylvania), Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus (ASTM C177, ASTM International, West Conshohocken, Pennsylvania), Test Method for Steady-State Heat Transfer Properties of Pipe Insulation (ASTM C335, ASTM International, West Conshohocken, Pennsylvania), Thin Heater Thermal Conductivity Test (ASTM C1114, ASTM International, West Conshohocken, Pennsylvania), Determination of thermal resistance by means of guarded hot plate and heat flowmeter methods (EN 12667, British Standards Institution, UK), or Determination of This can be determined by methods known in the art, including steady-state thermal resistance and related properties - Guarded hot plate apparatus (ISO 8203, International Organization for Standardization, Switzerland).In the context of this disclosure, unless otherwise specified, thermal conductivity measurements are obtained in accordance with the ASTM C177 standard at atmospheric pressure, a temperature of about 37.5°C, and a compression of about 2 psi. Preferably, the aerogel materials or compositions of this disclosure have a thermal conductivity of about 50 mW / mK or less, about 40 mW / mK or less, about 30 mW / mK or less, about 25 mW / mK or less, about 20 mW / mK or less, about 18 mW / mK or less, about 16 mW / mK or less, about 14 mW / mK or less, about 12 mW / mK or less, about 10 mW / mK or less, about 5 mW / mK or less, or in the range between any two of these values.

[0054] In the context of this disclosure, the term “density” refers to a measured mass per unit volume of an aerogel material or composition. The term “density” generally refers to the true density of an aerogel material, as well as the bulk density of an aerogel composition. Density is typically expressed in kg / m³. 3or recorded as g / cc. The density of aerogel materials or compositions can be determined by methods known in the art, but are not limited to, Standard Test Method for Dimensions and Density of Preformed Block and Board-Type Thermal Insulation (ASTM C303, ASTM International, West Conshohocken, Pennsylvania), Standard Test Methods for Thickness and Density of Blanket or Batt Thermal Insulations (ASTM C167, ASTM International, West Conshohocken, Pennsylvania), or Determination of the apparent density of preformed pipe insulation (ISO 18098, International Organization for Standardization, Switzerland). In the context of this disclosure, unless otherwise specified, density measurements are obtained in accordance with the ASTM C167 standard. Preferably, the aerogel material or composition of the present disclosure has a density of about 0.60 g / cc or less, about 0.50 g / cc or less, about 0.40 g / cc or less, about 0.30 g / cc or less, about 0.25 g / cc or less, about 0.20 g / cc or less, about 0.18 g / cc or less, about 0.16 g / cc or less, about 0.14 g / cc or less, about 0.12 g / cc or less, about 0.10 g / cc or less, about 0.05 g / cc or less, about 0.01 g / cc or less, or in the range between any two of these values.

[0055] In the context of this disclosure, the term "hydrophobic" refers to a measure of the ability of an aerogel material or composition to repel water.

[0056] The hydrophobicity of an aerogel material or composition may be expressed in terms of its liquid water absorption rate. In the context of this disclosure, the term “liquid water absorption rate” refers to a measure of the aerogel material or composition’s ability to absorb or retain liquid water. Liquid water absorption rate may be expressed as the percentage (by weight or volume) of water absorbed or retained by the aerogel material or composition when exposed to liquid water under specific measurement conditions. The liquid water absorption of aerogel materials or compositions can be determined by methods known in the art, including, but not limited to, the Standard Test Method for Determining the Water Retention (Repellency) Characteristics of Fibrous Glass Insulation (ASTM C1511, ASTM International, West Conshohocken, Pennsylvania), the Standard Test Method for Water Absorption by Immersion of Thermal Insulation Materials (ASTM C1763, ASTM International, West Conshohocken, Pennsylvania), and Thermal insulating products for building applications: Determination of short-term water absorption by partial immersion (EN 1609, British Standards Institution, United Kingdom). Because different methods may yield different results, it should be understood that, in the context of this disclosure, unless otherwise specified, liquid water absorption measurements are obtained in accordance with the ASTM C1511 standard under ambient pressure and ambient temperature.In certain embodiments, the aerogel material or composition of the present disclosure may have a liquid water absorption rate in accordance with ASTM C1511 of about 100% by weight or less, about 80% by weight or less, about 60% by weight or less, about 50% by weight or less, about 40% by weight or less, about 30% by weight or less, about 20% by weight or less, about 15% by weight or less, about 10% by weight or less, about 8% by weight or less, about 5% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, about 0.1% by weight or less, or in a range between any two of these values. The aerogel materials or compositions of this disclosure may have a liquid water absorption rate in accordance with ASTM C1763, in the range of about 100% by volume or less, about 80% by weight or less, about 60% by weight or less, about 50% by weight or less, about 40% by weight or less, about 30% by weight or less, about 20% by weight or less, about 15% by weight or less, about 10% by weight or less, about 8% by weight or less, about 5% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, about 0.1% by weight or less, or in the range between any two of these values. An aerogel material or composition having an improved liquid water absorption rate compared to another aerogel material or composition has a lower liquid water absorption / retention rate compared to a reference aerogel material or composition.

[0057] The hydrophobicity of an aerogel material or composition can be expressed in terms of water vapor absorption. In the context of this disclosure, the term “water vapor absorption” refers to a measure of the potential for an aerogel material or composition to absorb water vapor. Water vapor absorption can be expressed as the percentage (by weight) of water absorbed or retained by the aerogel material or composition when exposed to water vapor under specific measurement conditions. The water vapor absorption of an aerogel material or composition can be determined by methods known in the art, including, but not limited to, the Standard Test Method for Determining the Water Vapor Sorption of Unfaced Mineral Fiber Insulation (ASTM C1104, ASTM International, West Conshohocken, Pennsylvania). Because different methods may yield different results, in the context of this disclosure, unless otherwise specified, measurements of water vapor absorption rate are obtained in accordance with the ASTM C1104 standard under ambient pressure and ambient temperature. Preferably, the aerogel material or composition of the present disclosure may have a water vapor absorption of about 50% by weight or less, about 40% by weight or less, about 30% by weight or less, about 20% by weight or less, about 15% by weight or less, about 10% by weight or less, about 8% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, about 0.1% by weight or less, or in the range of any two of these values. An aerogel material or composition having improved water vapor absorption compared to another aerogel material or composition has a lower water vapor absorption / retention rate compared to a reference aerogel material or composition.

[0058] The hydrophobicity of an aerogel material or composition can be expressed by measuring the equilibrium contact angle of a water droplet at the interface with the surface of the material. The aerogel materials or compositions of this disclosure may have a water contact angle of about 90° or more, about 120° or more, about 130° or more, about 140° or more, about 150° or more, about 160° or more, about 170° or more, about 175° or more, or in the range of any two of these values.

[0059] In the context of this disclosure, the terms “heat of combustion” and “HOC” refer to measured values ​​of the amount of thermal energy released during the combustion of an aerogel material or composition. Heat of combustion is typically recorded as calories (cal / g) of thermal energy released per gram of aerogel material or composition, or as megajoules (MJ / kg) of thermal energy released per kilogram of aerogel material or composition. The heat of combustion of a material or composition can be determined by methods known in the art, including, but not limited to, Reaction to fire tests for products—Determination of the gross heat of combustion (calorific value) (ISO 1716, International Organization for Standardization, Switzerland). In the context of this disclosure, measurements of heat of combustion are obtained according to conditions equivalent to those of the ISO 1716 standard, unless otherwise specified. Preferably, the aerogel compositions of the present disclosure may have a heat of combustion of about 750 cal / g or less, about 717 cal / g or less, about 700 cal / g or less, about 650 cal / g or less, about 600 cal / g or less, about 575 cal / g or less, about 550 cal / g or less, about 500 cal / g or less, about 450 cal / g or less, about 400 cal / g or less, about 350 cal / g or less, about 300 cal / g or less, about 250 cal / g or less, about 200 cal / g or less, about 150 cal / g or less, about 100 cal / g or less, about 50 cal / g or less, about 25 cal / g or less, about 10 cal / g or less, or in the range between any two of these values. An aerogel composition having an improved heat of combustion compared to another aerogel composition has a lower heat of combustion value compared to a reference aerogel composition. In certain embodiments of this disclosure, the HOC of the aerogel composite is improved by incorporating a fire-class additive into the aerogel composite.

[0060] In the context of this disclosure, all thermal analyses and related definitions refer to values ​​obtained in measurements performed by starting at 25°C and raising the temperature to 1000°C at a rate of 20°C / min in air at ambient pressure. Therefore, when measuring and calculating the onset of pyrolysis, peak heat release temperature, peak sound absorption temperature, etc., it is necessary to consider (or re-run under these conditions) any change in any of these parameters. In the context of this disclosure, "onset of pyrolysis of hydrophobic organic materials," "onset of pyrolysis," and "T d The term "onset of thermal decomposition" refers to a measured value of the lowest ambient temperature at which a rapid exothermic reaction from the decomposition of a hydrophobic organic material occurs within the material or composition. The onset of thermal decomposition of a material or composition can be measured using thermogravimetric analysis (TGA). The TGA curve of a material shows the weight loss (mass%) of the material as it is exposed to an increase in ambient temperature. The onset of thermal decomposition of a material can be correlated with the intersection of the following tangent to the TGA curve, the line tangent to the baseline of the TGA curve, and the line tangent to the TGA curve at the point of maximum gradient during the rapid decomposition event associated with the decomposition of a hydrophobic organic material. In the context of this disclosure, unless otherwise specified, the measured value of the onset of thermal decomposition of a hydrophobic organic material is obtained using the TGA analysis presented in this paragraph.

[0061] The onset of thermal decomposition of a material can also be measured using differential scanning calorimetry (DSC) analysis. The DSC curve of a material shows the thermal energy (mW / mg) released by the material as it is exposed to a gradual increase in ambient temperature. The onset of thermal decomposition temperature of a material can correlate with the point on the DSC curve where ΔmW / mg (change in thermal energy output) increases most significantly, thus indicating exothermic reaction from aerogel materials. In the context of this disclosure, measurements of the onset of thermal decomposition using DSC, TGA, or both are obtained using a temperature gradient rate of 20°C / min, as further defined in the previous paragraph, unless otherwise specified. DSC and TGA each provide similar values ​​for this onset of thermal decomposition, and often the tests are performed simultaneously, resulting in results from both. In certain embodiments, the aerogel materials or compositions of the Disclosure have a thermal decomposition initiation at a range of about 300°C or higher, about 320°C or higher, about 340°C or higher, about 360°C or higher, about 380°C or higher, about 400°C or higher, about 415°C or higher, about 420°C or higher, about 440°C or higher, about 460°C or higher, about 480°C or higher, about 500°C or higher, about 550°C or higher, about 575°C or higher, about 600°C or higher, or between any two of these values. In the context of this Spectrum, for example, a first composition having a higher thermal decomposition initiation than a second composition is considered an improvement over the second composition. Herein, the thermal decomposition initiation of a composition or material is considered to increase with the addition of one or more fire-class additives compared to a composition without any fire-class additives.

[0062] In the context of this disclosure, the term “initiation of pyrolysis” refers to a measured value of the lowest ambient temperature at which an endothermic reaction from decomposition or dehydration occurs within a material or composition. The initiation of pyrolysis of a material or composition can be measured using thermogravimetric analysis (TGA). The TGA curve of a material shows the weight loss (mass%) of the material as it is exposed to an increase in ambient temperature. The initiation of pyrolysis of a material may correlate with the intersection of the following tangents to the TGA curve: the line tangent to the baseline of the TGA curve and the line tangent to the TGA curve at the point of maximum gradient during rapid endothermic decomposition or dehydration of the material. For example, Figure 1 is a graph showing the TGA / DSC analysis of an exemplary aerogel composition of this disclosure. The initiation of pyrolysis of the exemplary aerogel composition analyzed in Figure 1 is approximately 412°C based on the tangent technique discussed herein. In the context of this disclosure, unless otherwise specified, measured values ​​of the initiation of endothermic decomposition of a material or composition are obtained using the TGA analysis presented in this paragraph.

[0063] In the context of this disclosure, the terms “furnace temperature rise” and “ΔTR” refer to a measured difference between the maximum temperature (TMAX) of a material or composition under pyrolysis conditions and the baseline temperature (usually the final temperature, i.e., TFIN) of that material or composition under pyrolysis conditions. Furnace temperature rise is usually recorded in Celsius or °C. The furnace temperature rise of a material or composition can be determined by methods known in the art, including, but not limited to, the Non-combustibility test (EN ISO 1182, International Organization for Standardization, Switzerland, adopted by EN). In the context of this disclosure, unless otherwise specified, measured furnace temperature rises are obtained under conditions equivalent to those of EN ISO 1182 (Reaction to fire tests for building and transport products: Non-combustibility test). In certain embodiments, the aerogel compositions of this disclosure may have furnace temperature rises in the range of about 100°C or less, about 90°C or less, about 80°C or less, about 70°C or less, about 60°C or less, about 50°C or less, about 45°C or less, about 40°C or less, about 38°C or less, about 36°C or less, about 34°C or less, about 32°C or less, about 30°C or less, about 28°C or less, about 26°C or less, about 24°C or less, or between any two of these values. In the context of compositional stability at high temperatures, for example, a first composition having a furnace temperature rise lower than that of a second composition is considered an improvement over the second composition. Herein, the furnace temperature rise of a composition is considered to be reduced when one or more fire-class additives are added compared to a composition that does not contain any fire-class additives.

[0064] In the context of this disclosure, the terms “flame time” and “TFLAME” refer to the measurement of a sustained flame of a material or composition under thermal decomposition conditions, where “sustained flame” is the persistence of the flame in any portion of the visible part of the sample lasting for 5 seconds or more. Flame times are typically recorded in seconds or minutes. The flame times of a material or composition can be determined by methods known in the art, including, but not limited to, the Non-combustibility test (EN ISO 1182, International Organization for Standardization, Switzerland, adopted by EN). In the context of this disclosure, unless otherwise specified, flame time measurements are obtained under conditions equivalent to the EN ISO 1182 standard (Reaction to fire tests for building and transport products: Non-combustibility test). In certain embodiments, the aerogel compositions of this disclosure have flame times in the range of about 30 seconds or less, about 25 seconds or less, about 20 seconds or less, about 15 seconds or less, about 10 seconds or less, about 5 seconds or less, about 2 seconds or less, or between any two of these values. In the context of this specification, for example, a first composition having a shorter flame time than a second composition is considered an improvement over the second composition. This specification considers that the flame time of a composition is reduced when one or more fire-class additives are added compared to a composition without any fire-class additives.

[0065] In the context of this disclosure, the terms “mass loss” and “ΔM” refer to measured amounts of material, composition, or composite material lost or burned under thermal decomposition conditions. Mass loss is typically recorded as a weight percentage or wt%. The mass loss of a material, composition, or composite material can be determined by methods known in the art, including, but not limited to, the Non-combustibility test (EN ISO 1182, International Organization for Standardization, Switzerland, adopted by EN). In the context of this disclosure, unless otherwise specified, mass loss measurements are obtained under conditions equivalent to those of EN ISO 1182 (Reaction to fire tests for building and transport products: Non-combustibility test). In certain embodiments, the aerogel compositions of this disclosure may have a mass loss of about 50% or less, about 40% or less, about 30% or less, about 28% or less, about 26% or less, about 24% or less, about 22% or less, about 20% or less, about 18% or less, about 16% or less, or a range between any two of these values. In the context of this specification, for example, a first composition having a mass loss lower than that of a second composition is considered an improvement over the second composition. In this specification, the mass loss of a composition is considered to be reduced when one or more fire-class additives are added compared to a composition that does not contain any fire-class additives.

[0066] In the context of this disclosure, the term “peak heat release temperature” refers to a measured value of the ambient temperature at which the heat release from decomposition is greatest. The peak heat release temperature of a material or composition can be measured using TGA analysis, differential scanning calorimetry (DSC), or a combination thereof. DSC and TGA each provide similar values ​​for peak heat release temperature, and often the tests are performed simultaneously, resulting in results from both. In a typical DSC analysis, the heat flow is plotted against the temperature at which it rises, and the peak heat release temperature is the temperature at which the highest peak occurs in such a curve. In the context of this disclosure, unless otherwise specified, measured values ​​of the peak heat release temperature of a material or composition are obtained using the TGA analysis presented in this paragraph.

[0067] In the context of this disclosure, the terms “low flammability” and “low combustibility” refer to materials or compositions that satisfy the following combinations of properties: i) furnace temperature rise of 50°C or less, ii) flame duration of 20 seconds or less, and iii) mass loss of 50 wt% or less. In the context of this disclosure, the terms “non-combustible” and “non-combustible” refer to materials or compositions that satisfy the following combinations of properties: i) furnace temperature rise of 40°C or less, ii) flame duration of 2 seconds or less, and iii) mass loss of 30 wt% or less. As described herein, the flammability of a composition (e.g., a combination of furnace temperature rise, flame duration, and mass loss) is intended to be reduced by the inclusion of one or more fire-class additives.

[0068] In the context of this disclosure, the terms “low flammability” and “low combustion” refer to low flammability materials or compositions having a total heat of combustion (HOC) of 3 MJ / kg or less. In the context of this disclosure, the terms “non-flammability” and “non-combustible” refer to non-flammability materials or compositions having a heat of combustion (HOC) of 2 MJ / kg or less. The HOC of a composition is intended to be reduced by including one or more fire-class additives as described herein.

[0069] Aerogels are described as interconnected structural frameworks most commonly composed of interconnected oligomers, polymers, or colloidal particles. Aerogel frameworks may be fabricated from a range of precursor materials, including inorganic precursor materials (such as precursors used in the production of silica-based aerogels), organic precursor materials (such as precursors used in the production of carbon-based aerogels), hybrid inorganic / organic precursor materials, and combinations thereof. In the context of this disclosure, the term “amalgam aerogel” refers to an aerogel fabricated from a combination of two or more different gel precursors.

[0070] Inorganic aerogels are generally formed from metal oxide or metal alkoxide materials.

[0071] Metal oxide or metal alkoxide materials may be based on oxides or alkoxides of any metal capable of forming oxides. Such metals include, but are not limited to, silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium, and cerium. Inorganic silica aerogels are conventionally produced by hydrolysis and condensation of silica-based alkoxides (such as tetraethoxysilane) or by gelation of silicic acid or water glass. Other relevant inorganic precursor materials for silica-based aerogel synthesis include, but are not limited to, metal silicates such as sodium silicate or potassium silicate, alkoxysilanes, partially hydrolyzed alkoxysilanes, tetraethoxysilane (TEOS), partially hydrolyzed TEOS, condensed polymers of TEOS, tetramethoxysilane (TMOS), partially hydrolyzed TMOS, condensed polymers of TMOS, tetra-n-propoxysilane, partially hydrolyzed and / or condensed polymers of tetra-n-propoxysilane, polyethylsilicates, partially hydrolyzed polyethylsilicates, monomeric alkylalkoxysilanes, bis-trialalkoxyalkyl or arylsilanes, polyhedral silsesquioxanes, or combinations thereof.

[0072] In certain embodiments of this disclosure, a pre-hydrolyzed TEOS, such as Silbond H-5 (SBH5, Silbond Corp), which is hydrolyzed at a water / silica ratio of about 1.9 to 2, may be used as a commercially available product or may be further hydrolyzed before being incorporated into the gelation process. Partially hydrolyzed TEOS or TMOS, such as polyethyl silicate (Silbond 40) or polymethyl silicate, may also be used as a commercially available product or may be further hydrolyzed before being incorporated into the gelation process.

[0073] Inorganic aerogels may also contain gel precursors comprising at least one hydrophobic group, such as alkyl metal alkoxides, cycloalkyl metal alkoxides, and aryl metal alkoxides, which can impart or improve certain gel properties such as stability and hydrophobicity. Inorganic silica aerogels may particularly contain hydrophobic precursors such as alkylsilanes or arylsilanes. Hydrophobic gel precursors can be used as primary precursor materials for forming the backbone of gel materials. However, hydrophobic gel precursors are more commonly used as co-precursors in combination with simple metal alkoxides in the formation of amalgam aerogels. Hydrophobic inorganic precursor materials for silica-based aerogel synthesis include, but are not limited to, trimethylmethoxysilane [TMS], dimethyldimethoxysilane [DMS], methyltrimethoxysilane [MTMS], trimethylethoxysilane, dimethyldiethoxysilane [DMDES], methyltriethoxysilane [MTES], ethyltriethoxysilane [ETES], diethyldiethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane [PhTES], hexamethyldisilazane, and hexaethyldisilazane.

[0074] In exemplary embodiments, the relative amounts of one or more hydrophobic gel precursors to other inorganic precursor materials are selected to produce aerogel materials or compositions having hydrophobic properties as disclosed herein, while maintaining other properties such as thermal conductivity, heat of combustion, initiation of thermal decomposition, and / or processability. For example, the use of smaller amounts of one or more hydrophobic gel precursors may reduce the hydrophobic properties, resulting in materials having, for example, higher liquid water absorption or water vapor water absorption. In another example, the use of larger amounts of one or more hydrophobic gel precursors may negatively affect thermal conductivity, combustion, and / or self-heating properties. In exemplary embodiments, the hydrophobic aerogel materials and compositions of this disclosure may have a hydrophobic content in the range of about 20% by weight, about 30% by weight, about 40% by weight, about 50% by weight, or between any two of these values. For example, an exemplary aerogel composition has a hydrophobic content of about 36% by weight.

[0075] In the context of this disclosure, the hydrophobic content obtained from the hydrophobic gel precursor is determined based on the ratio of the weight contribution of the hydrolysis products of the hydrophobic gel precursor to the weight contribution of all solids after hydrolysis. Table 1 below shows exemplary compositions containing TEOS, DMDES, and MTES that yield a hydrophobic content of approximately 36% by weight ± 2% by weight.

[0076] TIFF0007835684000001.tif40170

[0077] Table 2 below shows exemplary compositions containing S40, DMDES, and MTES, resulting in a hydrophobic content of approximately 36% ± 2% by weight.

[0078] TIFF0007835684000002.tif40170

[0079] Aerogels may also be treated to impart or improve hydrophobicity. However, embodiments of aerogel compositions according to this disclosure have hydrophobic properties without any additional treatment to impart such properties. In the context of this disclosure, the term “inherently hydrophobic” means an aerogel having hydrophobic properties according to the embodiments disclosed herein without any treatment, e.g., treatment of the wet gel and / or treatment of the dry aerogel form, to impart or improve hydrophobicity.

[0080] For example, aerogels and aerogel compositions according to embodiments disclosed herein may be hydrophobic based solely on the hydrophobicity provided by the components of the gel precursor, in combination with other disclosed properties, such as heat of combustion, initiation of thermal decomposition, or a combination of such properties. In such embodiments, the gel precursor generates a sufficient amount of hydrophobic-bonded silicon to produce an aerogel composition that is hydrophobic with respect to the range of liquid water absorption and water vapor absorption disclosed herein, without further treatment with a hydrophobicizing agent (such as HMDZ).

[0081] In the context of this disclosure, the term “hydrophobic-bonded silicon” refers to a silicon atom in the backbone of a gel or aerogel that contains at least one hydrophobic group covalently bonded to a silicon atom. Examples of hydrophobic-bonded silicon include, but are not limited to, silicon atoms of silica groups in the backbone of a gel formed from a gel precursor containing at least one hydrophobic group (such as MTES or DMDES). In exemplary embodiments, an aerogel composition obtained from one or more hydrophobic gel precursors disclosed herein may have a surface group containing a hydrophobic group of the formula Si-R, where R is an alkyl group. For example, hydrophobic groups in this disclosure include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, octyl, phenyl, or other substituted or unsubstituted hydrophobic organic groups known to those skilled in the art. In the context of this disclosure, the terms “hydrophobic group,” “hydrophobic organic material,” and “hydrophobic organic content” specifically exclude readily hydrolyzable organosilicon-bonded alkoxy groups in the backbone of gel materials, which are products of reactions between organic solvents and silanol groups. Such excluded groups can be distinguished from the hydrophobic organic content of this disclosure by NMR analysis.

[0082] In the context of this disclosure, the terms “aliphatic hydrophobic group,” “aliphatic hydrophobic organic material,” and “aliphatic hydrophobic organic content” refer to hydrophobic groups of hydrophobic-bonded silicon limited to aliphatic hydrocarbons, which include, but are not limited to, hydrocarbon moieties containing 1 to 40 carbon atoms (but not aromatic), which may be saturated or unsaturated, and may include linear, branched, cyclic moieties (including condensed, crosslinked, and spirocondensed polycyclic moieties), or combinations thereof, e.g., alkyl, alkenyl, alkynyl, (cycloalkyl)alkyl, (cycloalkenyl)alkyl, or (cycloalkyl)alkenyl moieties, and heteroaliphatic moieties (where one or more carbon atoms are independently replaced by one or more atoms selected from the group consisting of oxygen, sulfur, nitrogen, or phosphorus). In certain embodiments of this disclosure, at least 50% of the hydrophobic organic material of the aerogel composition contains aliphatic hydrophobic groups.

[0083] The amount of hydrophobic bonded silicon contained in the aerogel can be analyzed using NMR spectroscopy such as CP / MAS 29 Si solid-state NMR. The NMR analysis of the aerogel enables the characterization and relative quantification of M-type hydrophobic bonded silicon (monofunctional silica such as TMS derivatives), D-type hydrophobic bonded silicon (bifunctional silica such as DMDES derivatives), T-type hydrophobic bonded silicon (trifunctional silica such as MTES derivatives), and Q-type silicon (tetrafunctional silica such as TEOS derivatives). NMR analysis can also be used to analyze the bonding chemistry of hydrophobic bonded silicon contained in the aerogel by enabling the classification of specific types of hydrophobic bonded silicon into subtypes (e.g., the T 1 species, T 2 species, and T 3 species). Specific details regarding the NMR analysis of silica materials can be found on pages 7 to 9 of the paper "Applications of Solid-State NMR to the Study of Organic / Inorganic Multicomponent Materials" by Geppi et al. (Appl. Spec. Rev. (2008), 44-1: 1-89), which is incorporated herein by reference according to the specifically cited pages.

[0084] CP / MAS 29 The characterization of hydrophobic bonded silicon in CP / MAS 1 Si NMR analysis is based on the peaks of the following chemical shifts, namely M 1 (30 to 10 ppm), D 2 (10 to -10 ppm), D 1 (-10 to -20 ppm), T 2 (-30 to -40 ppm), T 3 (-40 to -50 ppm), T 2 (-50 to -70 ppm), Q 3 (-70 to -85 ppm), Q 4(-95 to -110 ppm) can be used as a basis. These chemical shift peaks are approximate and illustrative and are not intended to be limiting or definitive. The exact chemical shift peaks resulting from various silicon species in the material may depend on the specific chemical composition of the material and can generally be deciphered by routine experiments and analyses by those skilled in the art.

[0085] The aerogel material disclosed herein is T 1-2 :T 3 The ratio may be approximately 0.01 to approximately 0.5, approximately 0.01 to approximately 0.3, or approximately 0.1 to approximately 0.3. 1-2 :T 3 The ratio is T 3 T for species 1 Seeds and T 2 This represents the ratio of combinations with the species. 1 , T 2 and T 3 The amount is, as defined earlier, 29 In Si NMR analysis, T 1 seeds, T 2 species or T 3 The Q of the species can be quantified by integrating the peaks of the individual chemical shifts associated with each species. The aerogel materials of this disclosure have Q values ​​of about 0.1 to 2.5, about 0.1 to 2.0, about 0.1 to 1.5, about 0.1 to 1.0, or about 0.5 to 1.0. 2-3 :Q 4 It can have the ratio of Q. 2-3 :Q 4 The ratio is Q 4 Q for species 2 Species and Q 3 This represents the ratio of the combination of species. Q 2 Q 3 and Q 4 The amount is, as defined earlier, 29 Q in Si NMR analysis 2 seeds, Q 3 Seed or Q 4 This can be quantified by integrating the peaks of individual chemical shifts associated with each species.

[0086] In the context of this disclosure, the terms “hydrophobic organic content” or “hydrophobic content” refer to the amount of hydrophobic organic material bonded to the backbone of an aerogel material or composition. The hydrophobic organic content of an aerogel material or composition can be expressed as a weight percentage of the amount of hydrophobic organic material in the aerogel backbone relative to the total amount of material in the aerogel material or composition. The hydrophobic organic content can be calculated by those skilled in the art based on the properties and relative concentrations of the materials used in the manufacture of the aerogel material or composition. The hydrophobic organic content can also be measured using thermogravimetric analysis (TGA) in an inert atmosphere. Specifically, the proportion of hydrophobic organic material in the aerogel can be correlated with the proportion of weight loss of the hydrophobic aerogel material or composition when exposed to the heat of combustion temperature between TGA analyses, with adjustments made for water loss, residual solvent loss, and loss of readily hydrolyzable alkoxy groups between TGA analyses. The hydrophobic content of the aerogel composition of the present invention can be measured and determined using other alternative techniques known to those skilled in the art, such as differential scanning calorimetry, elemental analysis (especially carbon), chromatography techniques, nuclear magnetic resonance spectroscopy, and other analytical techniques. In certain cases, a combination of known techniques may be useful or necessary to determine the hydrophobic content of the aerogel composition of the present invention.

[0087] The aerogel material or composition of this disclosure may have a hydrophobic organic content of 50% by weight or less, 40% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 8% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or in a range between any two of these values.

[0088] The term "fuel content" refers to the total amount of flammable material in an aerogel material or composition, which can be correlated with the total percentage of weight loss of the aerogel material or composition when exposed to a flammable thermal temperature during TGA or TG-DSC analysis, with adjustments made for water loss. The fuel content of an aerogel material or composition may include hydrophobic organic content, as well as other flammable materials, such as residual alcoholic solvents, filler materials, reinforcing materials, and readily hydrolyzable alkoxy groups.

[0089] In certain embodiments, the aerogels of the Disclosure are primarily inorganic silica aerogels formed from prepolymerized silica precursors, preferably as oligomers, or hydrolyzed silicates formed from silicon alkoxides in an alcohol solvent. In certain embodiments, such prepolymerized silica precursors or hydrolyzed silicates may be formed in situ from other precursors or silicates, such as alkoxysilanes or water glass. However, the Disclosure as a whole may be carried out using any other aerogel compositions known to those skilled in the art, and is not limited to any one precursor material or amalgam mixture of precursor materials.

[0090] As generally discussed above, in exemplary embodiments of the present disclosure, aerogels can be formed from gel precursors or combinations of gel precursors containing at least one hydrophobic group. Such aerogels, such as inorganic aerogels including silica-based aerogels, may contain hydrophobic-bound silicon. For example, the source of hydrophobic-bound silicon in the aerogel may be one or more hydrophobic precursor materials. In embodiments of the present disclosure, aerogels formed from such precursors may be hydrophobic. In some embodiments, aerogels formed from such precursors may be inherently hydrophobic.

[0091] In the context of this disclosure, the term “inherently hydrophobic” refers to a material that is hydrophobic without modification by a hydrophobic agent. For example, aerogels can be treated to impart or improve hydrophobicity. Hydrophobic treatment can be applied to sol-gel solutions, wet gels before liquid-phase extraction, or aerogels after liquid-phase extraction. Hydrophobic treatment can be carried out by reacting hydroxyl moieties on the gel, such as silanol groups (Si-OH) present in the silica gel skeleton, with the functional groups of a hydrophobic agent. The resulting reaction converts the silanol groups and the hydrophobic agent into hydrophobic groups in the silica gel skeleton. Hydrophobic agent compounds undergo the following reaction, i.e., R N MX 4-N (Hydrophobic agent) + MOH (Silanol) → MOMR N (Hydrophobic group) + HX can react with the hydroxyl groups of the gel. The hydrophobic treatment can be carried out both on the outer macrosurface of the silica gel and on the inner pore surfaces within the porous network of the gel. Published U.S. Patent Application Publication 2016 / 0096949 (paragraphs 0044 to 0048) teaches the hydrophobic treatment and is incorporated herein by reference in accordance with the paragraphs cited individually. However, as stated above, the aerogel according to embodiments of the present disclosure is hydrophobic without hydrophobic treatment, for example, without treatment with a hydrophobic agent.

[0092] The production of aerogels generally involves the following steps: i) formation of a sol-gel solution, ii) formation of a gel from the sol-gel solution, and iii) extraction of the solvent from the gel material by innovative processing and extraction to obtain a dry aerogel material. This method is described in more detail below, particularly in relation to the formation of inorganic aerogels such as silica aerogels. However, the specific examples and illustrations presented herein are not intended to limit this disclosure to any particular type of aerogel and / or preparation method. This disclosure may include any aerogel formed by any relevant preparation method known to those skilled in the art.

[0093] The first step in forming an inorganic aerogel is generally the formation of a sol-gel solution by hydrolysis and condensation of a metal alkoxide precursor in an alcohol-based solvent. Key variables in the formation of an inorganic aerogel include the type of alkoxide precursor present in the sol-gel solution, the properties of the solvent, the processing temperature and pH of the sol-gel solution (which can be altered by the addition of an acid or base), and the precursor / solvent / water ratio in the sol-gel solution. Controlling these variables during the formation of the sol-gel solution allows for control of the growth and aggregation of the gel skeleton during the subsequent transition of the gel material from the "sol" state to the "gel" state. The properties of the resulting aerogel are influenced by the pH of the precursor solution and the molar ratio of the reactants, although any pH and molar ratio that enable gel formation can be used in this disclosure.

[0094] A sol-gel solution is formed by combining at least one gelling precursor with a solvent. Suitable solvents for forming sol-gel solutions include lower alcohols with 1 to 6 carbon atoms, preferably 2 to 4 carbon atoms, but other solvents known to those skilled in the art can be used. Examples of useful solvents include, but are not limited to, methanol, ethanol, isopropanol, ethyl acetate, acetate acetate, acetone, dichloromethane, and tetrahydrofuran. Multiple solvents can also be combined to achieve a desired level of dispersion or to optimize the properties of the gel material. Therefore, the selection of the optimal solvent for the sol-gel formation step and the gel formation step depends on the specific precursors, fillers, and additives incorporated into the sol-gel solution, as well as the target processing conditions for gelation and extraction of the liquid phase, and the desired properties of the final aerogel material.

[0095] Water may also be present in the precursor-solvent solution. The water acts to hydrolyze the metal alkoxide precursor to the metal hydroxide precursor. The hydrolysis reaction may be (using TEOS in ethanol solvent as an example): Si(OC2H5)4 + 4H2O → Si(OH)4 + 4(C2H5OH). The resulting hydrolyzed metal hydroxide precursor remains suspended in the solvent solution in a "sol" state, either as individual molecules or as small polymerized (or oligomerized) colloidal clusters of molecules. For example, polymerization / condensation of the Si(OH)4 precursor may occur as follows: 2Si(OH)4 = (OH)3Si-O-Si(OH)3 + H2O. This polymerization can continue until a colloidal cluster of polymerized (or oligomerized) SiO2 (silica) molecules is formed.

[0096] Acids and bases can be incorporated into sol-gel solutions to control the solution's pH and catalyze the hydrolysis and condensation reactions of precursor materials. Any acid can be used to catalyze the precursor reaction and obtain a lower pH solution, but preferred acids include HCl, H2SO4, H3PO4, oxalic acid, and acetic acid. Any base can similarly be used to catalyze the precursor reaction and obtain a higher pH solution, with NH4OH being a preferred base.

[0097] A strong base can be used to catalyze the precursor reaction, yielding a solution with a higher pH. Using a strong base to catalyze the precursor reaction allows for a significantly higher content of hydrophobic inorganic precursor material, such as MTES or DMDES, than would be possible with a weak base, such as a base containing NH4OH. In the context of this disclosure, the term “strong base” refers to both inorganic and organic bases. For example, the strong bases according to the embodiments herein include cations selected from the group consisting of lithium, calcium, sodium, potassium, rubidium, barium, strontium, and guanidinium. In another example, the basic catalyst used to catalyze the precursor reaction may include catalytic amounts of sodium hydroxide, lithium hydroxide, calcium hydroxide, potassium hydroxide, strontium hydroxide, barium hydroxide, guanidine hydroxide, sodium hydroxide, tetrabutylammonium hydroxide, tetramethylammonium hydroxide, choline hydroxide, phosphonium hydroxide, DABCO, DBU, guanidine derivatives, amidine, or phosphazene.

[0098] The sol-gel solution may contain further co-gelling precursors, as well as filler materials and other additives. The filler materials and other additives may be dispensed into the sol-gel solution at any point before or during gel formation. The filler materials and other additives may also be incorporated into the gel material after gelation by various techniques known to those skilled in the art. Preferably, the sol-gel solution, comprising the gelling precursor, solvent, catalyst, water, filler materials, and other additives, is a homogeneous solution capable of forming an effective gel under appropriate conditions.

[0099] Once a sol-gel solution is formed and optimized, the gel-forming components in the sol-gel can be transferred to the gel material. The process of transferring the gel-forming components to the gel material includes an initial gel-forming step in which the gel solidifies to the gelation point of the gel material. The gelation point of the gel material can be considered the point in which the gelling solution exhibits flow resistance and / or forms a substantially continuous polymer backbone over its entire volume. Various gel-forming techniques are known to those skilled in the art. Examples, but not limited to, include keeping the mixture static for a sufficient period of time, adjusting the pH of the solution, adjusting the temperature of the solution, directing a form of energy towards the mixture (ultraviolet light, visible light, infrared light, microwaves, ultrasound, particle radiation, electromagnetic radiation), or a combination thereof.

[0100] The process of transferring gel-forming components to a gel material may also include a maturation step (also called curing) before liquid-phase extraction. Mature the gel material after reaching the gelation point can further strengthen the gel backbone by increasing the number of crosslinks in the network. The duration of gel maturation can be adjusted to control various properties within the resulting aerogel material. This maturation process may be useful in preventing potential volume loss and shrinkage during liquid-phase extraction. Maturation can include maintaining the gel in a static state for an extended period (before extraction), maintaining the gel at a high temperature, adding crosslinking-promoting compounds, or any combination thereof. Preferred temperatures for maturation are typically between approximately 10°C and 100°C, although other suitable temperatures are also considered herein. The maturation of the gel material typically continues until the extraction of the liquid phase of the wet gel material.

[0101] The time required to transfer the gel-forming material to the gel material includes both the duration of the initial gel formation (from the start of gelation to the point of gelation) and the duration of subsequent hardening and maturation of either the gel material or the gel (from the point of gelation to the start of liquid phase extraction) before the extraction of the liquid phase. The total time required to transfer the gel-forming material to the gel material is typically between about 1 minute and several days, preferably about 30 hours or less, about 24 hours or less, about 15 hours or less, about 10 hours or less, about 6 hours or less, about 4 hours or less, about 2 hours or less, about 1 hour or less, about 30 minutes or less, or about 15 minutes or less.

[0102] The resulting gel material can be washed with a suitable secondary solvent to replace the primary reaction solvent present in the wet gel. Such secondary solvents may be linear monohydric alcohols having one or more aliphatic carbon atoms, dihydric alcohols having two or more carbon atoms, branched alcohols, cyclic alcohols, alicyclic alcohols, aromatic alcohols, polyhydric alcohols, ethers, ketones, cyclic ethers, or derivatives thereof.

[0103] Once a gel material is formed and processed, the liquid phase of the gel can then be at least partially extracted from the wet gel using extraction methods, including innovative processing and extraction techniques, to form an aerogel material. Extraction of the liquid phase plays a crucial role, among other factors, in manipulating the properties of the aerogel, such as porosity and density, as well as related properties such as thermal conductivity. Generally, aerogels are obtained by extracting the liquid phase from the gel in a manner that causes low shrinkage in the porous network and framework of the wet gel.

[0104] Aerogels are generally formed by removing a liquid mobile phase from a gel material at temperatures and pressures near or above the critical point of the liquid mobile phase. Upon reaching the critical point (near critical, i.e., the system's pressure and temperature are above the critical pressure and critical temperature, respectively) or exceeding the critical point (supercritical), a new supercritical phase distinct from the liquid or gas phase appears in the fluid. The solvent can then be removed without introducing any associated mass transfer limitations related to the liquid-vapor interface, capillary pressure, or typically the liquid-vapor boundary. Furthermore, the supercritical phase is generally more miscible with organic solvents and therefore has better extraction capabilities. Co-solvents and solvent exchange are also commonly used to optimize the supercritical fluid drying process.

[0105] If evaporation or extraction occurs below the supercritical point, capillary forces resulting from the evaporation of the liquid can cause shrinkage and pore collapse within the gel material. Such adverse effects of capillary forces can be mitigated by maintaining the mobile phase near or above the critical pressure and temperature during the solvent extraction process. In certain embodiments of this disclosure, the use of near-critical conditions just below the critical point of the solvent system allows for the production of aerogel materials or compositions with sufficiently low shrinkage, and thus commercially viable final products.

[0106] Several additional aerogel extraction techniques are known in the art, including various approaches to the use of supercritical fluids in the drying of aerogels. For example, Kistler (J. Phys. Chem. (1932) 36:52-64) describes a simple supercritical extraction process in which the gel solvent is maintained above its critical pressure and critical temperature, thereby reducing the evaporative capillary forces and maintaining the structural integrity of the gel network. U.S. Patent No. 4,610,863 describes an extraction process in which the gel solvent is exchanged with liquid carbon dioxide, followed by extraction under conditions in which the carbon dioxide is in a supercritical state. U.S. Patent No. 6,670,402 teaches the extraction of a liquid phase from a gel via rapid solvent exchange by injecting supercritical (not liquid) carbon dioxide into an extractor preheated and pre-pressurized substantially above a supercritical state, thereby generating an aerogel. U.S. Patent No. 5,962,539 describes a method for obtaining an aerogel from a polymer material in the form of a sol-gel in an organic solvent by exchanging an organic solvent with a fluid having a critical temperature below the polymer decomposition temperature and supercritically extracting the fluid / sol-gel. U.S. Patent No. 6,315,971 discloses a method for producing a gel composition, comprising drying a wet gel containing a gel solid and a desiccant, and removing the desiccant under sufficiently dry conditions to reduce the shrinkage of the gel during drying. U.S. Patent No. 5,420,168 describes a method for producing a resorcinol / formaldehyde aerogel using a simple air-drying procedure. U.S. Patent No. 5,565,142 describes a drying technique for modifying the gel surface to be stronger and more hydrophobic so that the gel skeleton and pores can withstand collapse during ambient drying or subcritical extraction. Other examples of extracting the liquid phase from aerogel materials can be found in U.S. Patents No. 5,275,796 and No. 5,395,805.

[0107] One embodiment of extracting the liquid phase from a wet gel utilizes a supercritical state of carbon dioxide, which includes, for example, first substantially replacing the primary solvent present in the gel's pore network with liquid carbon dioxide. The wet gel (typically in an autoclave) is then heated above the critical temperature of carbon dioxide (approximately 31.06°C) to raise the system pressure to a level higher than the critical pressure of carbon dioxide (approximately 1070 psig). Slight variations in the pressure around the gel material can facilitate the removal of the supercritical carbon dioxide fluid from the gel. Carbon dioxide can be recirculated through the extraction system to facilitate the continuous removal of the primary solvent from the wet gel. Finally, the temperature and pressure are slowly returned to ambient conditions to produce a dry aerogel material. The carbon dioxide can also be pre-treated to a supercritical state before being injected into the extraction chamber.

[0108] One example of an alternative method for forming aerogels involves acidifying a basic metal oxide precursor (such as sodium silicate) in water to prepare a hydrogel. Salt byproducts can be removed from the silicate precursor by ion exchange and / or by washing the subsequently formed gel with water. Removal of water from the gel pores can be done by exchange with a polar organic solvent such as ethanol, methanol, or acetone. The liquid phase of the gel is then at least partially extracted using innovative processing and extraction techniques.

[0109] Another example of a different method for forming aerogels involves chemically modifying the matrix material in a wet gel state via the conversion of surface hydroxyl groups to hydrophobic trimethylsilyl ethers, thereby reducing the capillary pressure that causes damage at the solvent / pore interface, and thereby enabling liquid-phase extraction from the gel material at temperatures and pressures below the critical point of the solvent.

[0110] In yet another embodiment, the liquid (solvent) in the gel material may be frozen at a lower temperature, followed by a sublimation process to remove the solvent from the gel material. Such removal or drying of the solvent from the gel material is understood to be within the scope of the present disclosure. Such removal largely preserves the gel structure and therefore produces an aerogel with intrinsic properties.

[0111] Large-scale production of aerogel materials or compositions can be complicated by the difficulties associated with the continuous formation of gel materials on a large scale. Furthermore, there are difficulties associated with liquid-phase extraction from large quantities of gel material using innovative processing and extraction techniques. The aerogel materials or compositions of this disclosure are preferably suitable for large-scale production. In certain embodiments, the gel materials of this disclosure can be produced on a large scale by a continuous casting and gelation process. In certain embodiments, the aerogel materials or compositions of this disclosure are produced on a large scale and require the use of a large-scale extraction vessel. The large-scale extraction vessel of this disclosure is approximately 0.1 m³ 3 More than 0.25m 3 More than 0.5m 3 Above, or approximately 0.75m 3 An extraction vessel having the above volume may be included.

[0112] The aerogel composition of this disclosure may have a thickness of 15 mm or less, 10 mm or less, 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less.

[0113] Aerogel compositions may be reinforced with various reinforcing materials to achieve more flexible, elastic, and conformable composite products. Reinforcing materials can be added to the gel at any point in the gelation process to produce a wet-reinforced gel composition. The wet-reinforced gel composition can then be dried to produce a reinforced aerogel composition.

[0114] Aerogel compositions may be OCMF-reinforced with various open-cell macroporous skeletal reinforcing materials to achieve more flexible, resilient, and conformable composite products. The OCMF reinforcing material can be added to the gel at any point in the gelation process before gelation to produce a wet-reinforced gel composition. The wet-reinforced gel composition can then be dried to produce an OCMF-reinforced aerogel composition. The OCMF reinforcing material can be formed from organic polymer materials such as melamine or melamine derivatives and may exist in the form of continuous sheets or panels.

[0115] Melamine OCMF material can be produced from a melamine-formaldehyde precondensation solution. An aqueous solution of the melamine-formaldehyde condensate is produced by combining the melamine-formaldehyde precondensate with a solvent, emulsifier / dispersant, curing agent such as an acid, and blowing agent such as a C5 to C7 hydrocarbon. The melamine-formaldehyde solution or resin is then cured at a high temperature exceeding the boiling point of the blowing agent to produce OCMF containing numerous interconnected three-dimensional branched melamine structures, with corresponding networks of interconnected pores incorporated within the framework. The melamine-formaldehyde precondensate generally has a formaldehyde-to-melamine molar ratio ranging from 5:1 to 1.3:1, typically from 3.5:1 to 1.5:1. The precondensate can be in the form of a powder, spray, resin, or solution. The solvent contained in the melamine-formaldehyde precondensation solution can include alcohols such as methanol, ethanol, or butanol.

[0116] The emulsifier / dispersant contained in the melamine-formaldehyde pre-condensation solution may include anionic surfactants, cationic emulsifiers, or nonionic surfactants. Useful anionic surfactants include, but are not limited to, diphenylene oxide sulfonates, alkane- and alkylbenzene sulfonates, alkylnaphthalene sulfonates, olefin sulfonates, alkyl ether sulfonates, fatty alcohol sulfates, ether sulfates, α-sulfo fatty acid esters, acylaminoalkane sulfonates, acyl isethionates, alkyl ether carboxylates, N-acyl sarcosinates, alkyls, and alkyl ether phosphates. Useful cationic emulsifiers include, but are not limited to, alkyltriammonium salts, alkylbenzyldimethylammonium salts, or alkylpyridinium salts. Useful nonionic surfactants include, but are not limited to, alkylphenol polyglycol ethers, fatty alcohol polyglycol ethers, fatty acid polyglycol ethers, fatty acid alkanolamides, ethylene oxide-propylene oxide block copolymers, amine oxides, glycerol fatty acid esters, sorbitan esters, and alkyl polyglycosides. Emulsifiers / dispersants can be added in amounts from 0.2% to 5% by weight relative to the melamine-formaldehyde precondensate.

[0117] The curing agents contained in the melamine-formaldehyde precondensation solution may include acidic compounds. The amounts of these curing agents are generally in the range of 0.01% to 20% by weight, and typically in the range of 0.05% to 5% by weight, based on the melamine-formaldehyde precondensate. Useful acidic compounds include, but are not limited to, those selected from the group consisting of organic and inorganic acids, such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, oxalic acid, toluenesulfonic acid, amidosulfonic acid, acid anhydrides, and mixtures thereof.

[0118] The blowing agent contained in the melamine-formaldehyde precondensation solution may include a physical blowing agent or a chemical blowing agent. Useful physical blowing agents include, but are not limited to, hydrocarbons, such as pentane and hexane; halogenated hydrocarbons, more specifically chlorinated and / or fluorinated hydrocarbons, such as methylene chloride, chloroform, trichloroethane, chlorofluorocarbons, and hydrochlorofluorocarbons (HCFCs); alcohols, such as methanol, ethanol, n-propanol, or isopropanol; ethers, ketones, and esters, such as methyl formate, ethyl formate, methyl acetate, or ethyl acetate; and gases such as air, nitrogen, or carbon dioxide. In certain embodiments, it is preferable to add a physical blowing agent having a boiling point from 0°C to 80°C. Useful chemical blowing agents include, but are not limited to, isocyanates mixed with water (releasing carbon dioxide as an active blowing agent); carbonates and / or bicarbonates mixed with acids (releasing carbon dioxide as an active blowing agent); and azo compounds, such as azodicarbonamides. The foaming agent is present in the melamine-formaldehyde precondensate solution in amounts ranging from 0.5% to 60% by weight, particularly 1% to 40% by weight, and in specific embodiments, 1.5% to 30% by weight, based on the melamine-formaldehyde precondensate.

[0119] A melamine-formaldehyde precondensation solution can be formed into a melamine OCMF material by heating the solution to a temperature generally exceeding the boiling point of the blowing agent used, thereby forming an OCMF containing numerous interconnected three-dimensional branched melamine structures, with a corresponding network of interconnected open-cell pores incorporated within the framework. The introduction of thermal energy may be via electromagnetic radiation, for example, 5 to 400 kW per kilogram of the mixture used in a frequency range of 0.2 to 100 GHz, more specifically 0.5 to 10 GHz, e.g., 5 to 200 kW, or 9 to 120 kW in certain embodiments, via high-frequency radiation. A magnetron is a useful dielectric radiation source, and one or more magnetrons can be used simultaneously.

[0120] OCMF materials can be dried to remove residual liquids (water, solvents, foaming agents). Post-treatment can also be used to hydrophobize the OCMF material. This post-treatment can utilize hydrophobic coating agents with high thermal stability and / or low flammability, such as silicones, silicone salts, or fluorinated compounds.

[0121] The density of melamine OCMF is generally in the range of 0.005 to 0.3 g / cc, for example, in the range of 0.01 to 0.2 g / cc, in certain embodiments in the range of 0.03 to 0.15 g / cc, or most specifically in the range of 0.05 to 0.15 g / cc. The average pore size of melamine OCMF is generally in the range of 10 μm to about 1000 μm, particularly in the range of 50 to 700 μm.

[0122] In one embodiment, the OCMF reinforcing material is incorporated into the aerogel composition as a continuous sheet. This process first involves producing a continuous sheet of OCMF-reinforced gel by casting or impregnating a gel precursor solution onto a continuous sheet of OCMF reinforcing material, and then forming the material into a reinforced gel composite sheet. Subsequently, the liquid can be at least partially extracted from the OCMF-reinforced gel composite sheet to produce a sheet-like OCMF-reinforced aerogel composition.

[0123] The aerogel composition may contain opacifying agents to reduce the radiative component of heat transfer. At any point before gel formation, opacifying compounds or their precursors may be dispersed in a mixture containing the gel precursor. Examples of opacifying compounds include, but are not limited to, boron carbide (B4C), diatomaceous earth, manganese ferrite, MnO, NiO, SnO, Ag2O, Bi2O3, carbon black, titanium oxide, titanium iron oxide, aluminum oxide, zirconium silicate, zirconium oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, titanium iron oxide (ilmenite), chromium oxide, carbides (e.g., SiC, TiC, or WC), or mixtures thereof. Examples of opacifying compound precursors include, but are not limited to, TiOSO4 or TiOCl2.

[0124] The aerogel composition may contain one or more fire-class additives. In the context of this disclosure, the term "fire-class additive" refers to a material that has an endothermic effect in the context of a reaction to fire and can be incorporated into the aerogel composition. Furthermore, in certain embodiments, the fire-class additive may cause the thermal decomposition (T) of the aerogel composition in which the fire-class additive is present. d Endothermic decomposition (E) is higher than the start of the decomposition and below 100°C. D ) begins, and in certain embodiments, the aerogel composition T in which a fire class additive is present d E is lower than 50°C. D It also has. In other words, the E of the Fire class additive D is, (T d -50℃) to (T d (within the range of +100℃) It has TIFF0007835684000003.tif30115.

[0125] Prior to or after incorporation with a sol (e.g., silica sol prepared from alkyl silicates or water glass in various ways as understood in the prior art), the Fire-class additives may be mixed, or otherwise dispersed, with a medium containing ethanol and optionally up to 10 vol% water. The mixture may be mixed and / or stirred as necessary to achieve a substantially uniform dispersion of the additives in the medium. While not bound by theory, utilizing the hydrated forms of the above clays and other Fire-class additives can yield additional endothermic effects. For example, halloysite clay (commercially available from Applied Minerals, Inc. under the trade name DRAGONITE, or simply as Halloysite by Imerys) and kaolinite clay are hydrated forms of aluminum silicate clay and have an endothermic effect by releasing hydrated water at high temperatures. As another example, hydrated forms of carbonates can release carbon dioxide when heated or at high temperatures.

[0126] In the context of this disclosure, the term “heat of dehydration” means the amount of heat required to vaporize water (and dihydroxylation, where applicable) from a material that is in a hydrated form when not exposed to high temperatures. Heat of dehydration is typically expressed on a unit weight basis.

[0127] In certain embodiments, the FireClass additives of the Disclosure have a thermal decomposition initiation at a range of about 350°C or higher, about 400°C or higher, about 450°C or higher, about 500°C or higher, about 550°C or higher, about 600°C or higher, about 650°C or higher, about 700°C or higher, about 750°C or higher, about 800°C or higher, or between any two of these values. In certain embodiments, the FireClass additives of the Disclosure have a thermal decomposition initiation at about 440°C or 570°C. In certain embodiments, the FireClass additives of the Disclosure have a thermal decomposition initiation at a range of more or less 50°C or lower, more or less 40°C or lower, more or less 30°C or lower, more or less 20°C or lower, more or less 10°C or lower, more or less 5°C or lower, or between any two of these values, compared to the Td of the aerogel composition (without the FireClass additive) into which the FireClass additive is incorporated.

[0128] The Fire Class additives of this disclosure include phyllosilicate clay (such as illite), kaolin or kaolinite (aluminum silicate, Al2Si2O5(OH)4), halloysite (aluminum silicate, Al2Si2O5(OH)4), endelite (aluminum silicate, Al2Si2O5(OH)4), mica (silica mineral), diaspore, gibbsite (aluminum hydroxide), montmorillonite, byderite, pyrophyllite (aluminum silicate, Al2Si4O10(OH)2), and non- Clay materials include, but are not limited to, toronite, brabiite, smectite, lebrierite, letrite, celadonite, attapulgite, chloroparl, volconscoite, alophane, lacévinite, dillnite, severite, mirosilite, cholerite, simolite and newtonite, magnesium hydroxide (or magnesium dihydrate, "MDH"), alumina trihydrate ("ATH"), dolomite and lithium carbonate, and carbonates. Among the clay materials, certain embodiments of the present disclosure use clay materials having at least a partial layered structure. In certain embodiments of the present disclosure, the clay material as a fire-class additive in the aerogel composition has at least some water, such as in a hydrated form. The additive may be in a hydrated crystalline form or may be hydrated in the production / processing of the composition of the present invention. In certain embodiments, the fire-class additive also includes low-melting-point additives that absorb heat without changing the chemical composition. An example of this class is low-melting-point glass, such as inert glass beads.

[0129] In certain embodiments of this disclosure, the clay material used as an additive to the aerogel composition, such as aluminosilicate clays like halloysite or kaolinite, is in a dehydrated form, such as metahaloysite or metakaolin. Other additives that may be useful in the compositions of this disclosure include, but are not limited to, wollastonite (calcium silicate) and titanium dioxide (TiO2). In certain embodiments, other additives may include, but are not limited to, infrared opacifiers such as titanium dioxide or silicon carbide, ceramicizing agents such as low-melting-point glass frit, calcium silicate, or carbides such as phosphates and sulfates. In certain embodiments, the additives may require special processing considerations, such as techniques to ensure that the additives are uniformly distributed and do not aggregate significantly to cause variability in product performance. Processing techniques may include additional static and dynamic mixers, stabilizers, adjustment of process conditions, and others known in the art. The amount of additives in the final aerogel composition may vary from 0.1% by weight to about 70% by weight, depending on the requirements of various other properties. In certain embodiments, the amount of additives in the final aerogel composition is between 10 and 60% by weight, and in certain preferred embodiments, it is between 20 and 40% by weight. In certain embodiments, there may be two or more types of additives. In certain embodiments, the amount of additives in the final reinforced aerogel composition is in the range of about 0.1% to about 10% by weight relative to the silica content of the aerogel. For example, one or more additives may be present in the range of about 0.5% to about 3.0% by weight relative to the silica content of the aerogel. One or more fire-class additives may also be present in the final aerogel composition.

[0130] In certain embodiments, improved high-temperature shrinkage properties can be imparted to the aerogel materials and compositions of the Disclosure by including additives, such as aluminosilicate clay materials such as halloysite or kaolin. Examples of high-temperature shrinkage test methods include the "Standard Test Method for Linear Shrinkage of Preformed High-Temperature Thermal Insulation Subjected to Soaking Heat" (ASTM C356, ASTM International, West Conshohocken, Pennsylvania). Such a test, referred to as "thermal soaking," involves exposing the material to temperatures exceeding 1000°C for up to 60 minutes. In certain exemplary embodiments, the aerogel materials or compositions of the Disclosure may have high-temperature shrinkage in the range of about 20% or less, about 15% or less, about 10% or less, about 6% or less, about 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, or any combination of linear shrinkage, width shrinkage, thickness shrinkage, or dimensional shrinkage.

[0131] In some exemplary embodiments, certain basic catalysts used to catalyze precursor reactions may introduce trace amounts of alkali metals into the aerogel composition. Trace levels of alkali in aerogel materials, e.g., 100 to 500 ppm, e.g., sodium or potassium, can adversely affect high-temperature shrinkage and thermal durability. However, without being bound by any particular mechanism or theory, aluminosilicate clay materials such as halloysite or kaolin can capture transient alkalis, e.g., sodium or potassium, thereby reducing or eliminating the effects of alkali on shrinkage and thermal durability. In specific embodiments of this disclosure, the aluminosilicate clay material is a dehydrated form, e.g., metahaloysite or metakaolin. For example, an aerogel material or composition containing more than about 0.5% by weight of metakaolin or metahaloysite may significantly reduce thermal shrinkage and improve thermal durability. In exemplary embodiments, the aerogel material or composition may contain amounts ranging from about 0.5% by weight to about 3.0% by weight of metakaolin or metahaloysite. In certain embodiments, the aerogel material or composition may contain more than about 0.5% by weight of metakaolin, for example, in an amount ranging from about 0.5% by weight to about 3.0% by weight.

[0132] In a preferred embodiment, the aerogel material or composition may contain metakaolin in an amount within the upper reference range relative to the silica content of the aerogel.

[0133] In certain embodiments of this disclosure, methods are provided for preparing OCMF-reinforced aerogel compositions having fire-class performance. The fire-class compositions of these embodiments also possess sufficient hydrophobicity for use as thermal insulation in industrial environments, as measured by water absorption and low thermal conductivity, to help meet the ever-demanding energy-saving needs. To obtain these combinations of desirable properties, simply adding additives or even just fire-class additives is not sufficient. While various substitutions and combinations or various additives can be tried to arrive at an optimized solution, such efforts are not always successful and present the risk of viable manufacturing with respect to reproducible quality control of these desired properties. A key aspect of these embodiments is to evaluate the thermal behavior of the composition that would otherwise give all desirable properties except fire-resistant performance (evaluated by thermogravimetric or differential scanning calorimetry) and to consider fire-class additives that closely match the temperature at which the thermal decomposition of the underlying composition begins, or alternatively, the temperature at which most of the heat is released with the initiation of the thermal decomposition of the fire-class additive, or the temperature at which most of the heat is absorbed.

[0134] In certain embodiments, the desired combustion characteristics of the final composition may include not only intrinsic properties such as combustion heat (ISO 1716), but also system combustion characteristics such as the response to combustion performance according to ISO 1182. In the case of ISO 1182, weight loss, furnace temperature rise, and flame time are evaluated when exposed to a furnace at a temperature of approximately 750°C.

[0135] OCMF-reinforced aerogel compositions may have various components that add fuel to the system. Furthermore, they may also have various other components that do not contribute as fuel but may hinder combustion when exposed to fire. Therefore, the combustion behavior of such systems cannot be simply predicted based on their components alone. In situations where multiple properties are desired, in certain embodiments, the composition should be achieved regardless of its fire-resistant properties, and the thermal performance of such an achieved composition should be evaluated to find an appropriate fire-class additive that imparts fire-resistant properties without compromising other properties that the starting composition sought to provide.

[0136] In certain embodiments, the initiation of pyrolysis is a key characteristic of the composition. In certain other embodiments, the peak heat release temperature may be a key characteristic for developing enhanced fire-resistant aerogel OCMF compositions. When multiple fuel components are present in a composition identified by multiple peaks in the DSC curve, such compositions function well by matching the peak heat release temperature of the OCMF-enhanced aerogel composition with a fire-class additive having an endothermic peak heat release temperature of 140°C, 120°C, 100°C, or within 80°C. In many embodiments, the endothermic peak heat release temperature is within 50°C.

[0137] Dry aerogel materials or compositions can be further processed to optimize the target properties of the aerogel material or composition. In certain embodiments, dry aerogel compositions may be subjected to one or more heat treatments, such as pyrolysis, to produce heat-treated aerogel compositions. Using carefully controlled heat treatments, the hydrocarbon fuel content of the aerogel material or composition can be reduced or stabilized, thereby improving the corresponding HOC and T of the aerogel material or composition. d The properties can be improved. In certain embodiments, the heat treatment of the dry aerogel composition can be carried out under a range of temperatures, pressures, durations, and atmospheric pressure conditions.

[0138] In certain embodiments of this disclosure, the dry aerogel composition may be subjected to a processing temperature of about 225°C or less. Heat treatment can remove volatile components present in the composition, such as ethanol and water. In certain embodiments of this disclosure, the dry aerogel composition may be subjected to a processing temperature of about 450°C or less. In certain embodiments of this disclosure, the dry aerogel composition may be subjected to a processing temperature of about 625°C or less. In certain embodiments of this disclosure, the dry aerogel composition may be subjected to a processing temperature of about 650°C or less. In some embodiments of this disclosure, the dry aerogel composition may be subjected to a processing temperature of 200°C or higher, 250°C or higher, 300°C or higher, 350°C or higher, 400°C or higher, 450°C or higher, 500°C or higher, 550°C or higher, 600°C or higher, 625°C or higher, 650°C or higher, 700°C or higher, 750°C or higher, 800°C or higher, or in the range of any two of these values. In certain embodiments of the Disclosure, the heat treatment of the aerogel material or composition of the Disclosure is limited to exposure to temperatures below 950°C, below 900°C, below 850°C, below 800°C, below 750°C, below 700°C, below 650°C, or below 600°C. In certain embodiments, the Disclosure enables controlled heat treatment to reduce or stabilize the hydrocarbon fuel content of the aerogel material (therefore, HOC and T). d The present invention provides aerogel materials, compositions, and processing methods that improve the corresponding properties of aerogel materials, and also enable aerogel materials to maintain a hydrophobic functional level at high temperatures, including exposure to temperatures of approximately 550°C or higher and exposure to temperatures of approximately 650°C or higher.

[0139] In certain embodiments of the present disclosure, the dry aerogel composition can be subjected to one or more heat treatments for a duration of 3 hours or more, 10 seconds to 3 hours, 10 seconds to 2 hours, 10 seconds to 1 hour, 10 seconds to 45 minutes, 10 seconds to 30 minutes, 10 seconds to 15 minutes, 10 seconds to 5 minutes, 10 seconds to 1 minute, 1 minute to 3 hours, 1 minute to 1 hour, 1 minute to 45 minutes, 1 minute to 30 minutes, 1 minute to 15 minutes, 1 minute to 5 minutes, 10 minutes to 3 hours, 10 minutes to 1 hour, 10 minutes to 45 minutes, 10 minutes to 30 minutes, 10 minutes to 15 minutes, 30 minutes to 3 hours, 30 minutes to 1 hour, 30 minutes to 45 minutes, 45 minutes to 3 hours, between 45 minutes and 90 minutes, between 45 minutes and 60 minutes, between 1 hour and 3 hours, between 1 hour and 2 hours, between 1 hour and 90 minutes, or between any two of these values.

[0140] In certain embodiments of the present disclosure, the dried aerogel composition may be subjected to a processing temperature of 200°C to 750°C for a duration of 10 seconds to 3 hours.

[0141] The heat treatment of aerogel materials or compositions can be carried out in a low-oxygen environment. In the context of this disclosure, the term “low-oxygen environment” refers to an atmosphere containing an oxygen concentration of 10 vol% or less (below the amount of oxygen in ambient air under standard conditions). A low-oxygen environment can include a positively pressurized atmosphere with a high concentration of inert gas, including but not limited to nitrogen, argon, helium, neon, and xenon. A low-oxygen environment can also include a vacuum atmosphere with a low concentration of oxygen, including vacuum and partial vacuum. A low-oxygen environment can further include an atmosphere contained in a sealed container, in which limited combustion consumes a portion of the oxygen content of the sealed atmosphere. A low-oxygen environment can include oxygen concentrations of 10 vol% or less, 8 vol% or less, 6 vol% or less, 5 vol% or less, 4 vol% or less, 3 vol% or less, 2 vol% or less, or 1 vol% or less. The low-oxygen environment may include 0.1 to 10 volume percent of oxygen, 0.1 to 5 volume percent of oxygen, 0.1 to 3 volume percent of oxygen, 0.1 to 2 volume percent of oxygen, or 0.1 to 1 volume percent of oxygen. In certain embodiments of the present disclosure, the hydrophobic aerogel material or composition is heat-treated in a low-oxygen atmosphere containing about 85% to about 99.9% inert gas (such as nitrogen). In preferred embodiments of the present disclosure, the dried hydrophobic aerogel composition is heat-treated in a low-oxygen atmosphere containing about 95% to about 99.9% inert gas (such as nitrogen) at a temperature of about 200°C to about 800°C for a duration of about 1 minute to about 3 hours.

[0142] Embodiments of the present disclosure can be carried out using any processing, extraction, and treatment techniques discussed herein, as well as other processing, extraction, and treatment techniques known to those skilled in the art for producing aerogels, aerogel-like materials, and aerogel compositions as defined herein.

[0143] Aerogel compositions may be reinforced with various fiber-reinforcement materials to achieve more flexible, resilient, and conformable composite products. A wet fiber-gel composition can be produced by adding the fiber-reinforcement material to the gel at any point in the gelation process. The wet gel composition can then be dried to produce a fiber-reinforced aerogel composition. The fiber-reinforcement material may be in the form of discrete fibers, woven materials, nonwoven materials, battings, webs, mats, and felts. The fiber-reinforcement material can be made from organic fiber materials, inorganic fiber materials, or combinations thereof.

[0144] In a preferred embodiment, the nonwoven fiber-reinforced material is incorporated into the aerogel composition as a continuous sheet of interconnected or interwoven fiber-reinforced material. This process first involves producing a continuous sheet of fiber-reinforced gel by casting or impregnating a gel precursor solution into a continuous sheet of interconnected or interwoven fiber-reinforced material. The liquid phase can then be at least partially extracted from the fiber-reinforced gel composite sheet to produce a sheet-like fiber-reinforced aerogel composition.

[0145] Aerogel compositions may also contain opacifying agents to reduce the radiative component of heat transfer. At any point before gel formation, opacifying compounds or their precursors can be dispersed in a mixture containing the gel precursor. Examples of opacifying compounds include, but are not limited to, boron carbide (B4C), diatomaceous earth, manganese ferrite, MnO, NiO, SnO, Ag2O, Bi2O3, carbon black, titanium dioxide, titanium iron oxide, aluminum oxide, zirconium silicate, zirconium oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, titanium iron oxide (ilmenite), chromium oxide, carbides (e.g., SiC, TiC, or WC), or mixtures thereof. Examples of opacifying compound precursors include, but are not limited to, TiOSO4 or TiOCl2.

[0146] The aerogel materials and compositions of this disclosure have been shown to be highly effective as thermal insulation materials. However, the applications of the methods and materials of this disclosure are not intended to be limited to applications related to insulation. The methods and materials of this disclosure can be applied to any system or application that would benefit from the specific combination of properties or procedures provided by the materials and methods of this disclosure.

[0147] The following embodiments provide various non-limiting embodiments and characteristics of the present disclosure.

[0148] (Example 1) Sols of both methyltriethoxysilane and polyethyl silicate are prepared separately by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a hydrophobic content is obtained from approximately 32% by weight of MTES, and an aerogel with an organic content of approximately 7.0% by weight in the aerogel material is obtained. Metakaolin is incorporated into the combined sols at a weight percentage of at least 0.5% relative to the silica content, and the mixture is then stirred for at least one hour.

[0149] Lithium hydroxide (1.0 M) is added to the combined sol at a concentration sufficient to achieve an aerogel density of approximately 0.07 to 0.085 g / cc. The catalytically activated metakaolin-containing sol is cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material is aged at 68°C for approximately 10 hours in an ethanol-aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0150] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching the expected material density of approximately 0.16 to 0.20 g / cc (given an aerogel density of 0.07 to 0.08 g / cc).

[0151] (Example 2) Sols of both methyltriethoxysilane (MTES) and polyethyl silicate are prepared separately by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a hydrophobic content is obtained from approximately 32% by weight of MTES, and an aerogel with an organic content of approximately 7.0% by weight in the aerogel material is obtained. Metakaolin is incorporated into the combined sols at a weight percentage of at least 0.5% relative to the silica content, and the mixture is then stirred for at least one hour.

[0152] Guanidine hydroxide (2M) is added to the combined sol at a concentration sufficient to achieve an aerogel density of approximately 0.07 to 0.085 g / cc. The catalytically activated metakaolin-containing sol is cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material is aged at 68°C for approximately 10 hours in an ethanol-aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0153] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching the expected material density of approximately 0.16 to 0.20 g / cc (given an aerogel density of 0.07 to 0.08 g / cc).

[0154] (Example 3) Sols of both methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) were prepared separately by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a hydrophobic content was obtained from approximately 36% by weight of MTES, and an aerogel with an organic content of approximately 8.0% by weight in the aerogel material was obtained. Metakaolin was incorporated into the combined sols at a weight percentage of at least 0.5% relative to the silica content, and the mixture was then stirred for at least 1 hour.

[0155] Guanidine hydroxide (2M) was added to the combined sol at a concentration sufficient to target an aerogel density of approximately 0.07 to 0.085 g / cc. The catalytically activated metakaolin-containing sol was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0156] The fiber-reinforced phase was a uniform nonwoven fabric material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consisted of approximately 65 wt% aerogel and 35 wt% fiber, reaching the expected material density of approximately 0.16 to 0.20 g / cc (given an aerogel density of 0.07 to 0.08 g / cc).

[0157] (Example 4) Individual sols of both methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) are prepared separately by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a hydrophobic content is obtained from approximately 36% by weight of MTES, and an aerogel with an organic content of approximately 8.0% by weight in the aerogel material is obtained. Metakaolin is incorporated into the combined sols at a weight percentage of at least 0.5% relative to the silica content, and the mixture is then stirred for at least one hour.

[0158] Lithium hydroxide (1.0 M) is added to the combined sol at a concentration sufficient to achieve an aerogel density of approximately 0.07 to 0.085 g / cc. The catalytically activated metakaolin-containing sol is cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material is aged at 68°C for approximately 10 hours in an ethanol-aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0159] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching the expected material density of approximately 0.16 to 0.20 g / cc (given an aerogel density of 0.07 to 0.08 g / cc).

[0160] (Example 5) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), were independently prepared by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel was obtained with a hydrophobic content of approximately 32.4 wt% MTES, approximately 3.6 wt% DMDES, and approximately 8.7 wt% organic content within the aerogel material. Metakaolin was incorporated into the sol at approximately 3.0 wt% relative to the silica content, and this was then stirred for more than 1 hour.

[0161] Guanidine hydroxide (2M) was added to the combined sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalyzed sol was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0162] The fiber-reinforced phase was a uniform nonwoven fabric material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consisted of approximately 65 wt% aerogel and 35 wt% fiber, achieving the expected material density of approximately 0.16 to 0.20 g / cc.

[0163] (Example 6) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), are prepared independently by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel is obtained having a hydrophobic content from approximately 32.4 wt% MTES, approximately 3.6 wt% DMDES, and approximately 8.7 wt% organic content within the aerogel material. Metakaolin is incorporated into the sol at approximately 3.0 wt% relative to the silica content, and this is then stirred for at least 1 hour.

[0164] Lithium hydroxide (1.0 M) was added to the combined sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalytically activated metakaolin-containing sol was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol-aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0165] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching an expected material density of approximately 0.16 to 0.20 g / cc.

[0166] (Example 7) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), were independently prepared by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel was obtained with a hydrophobic content of approximately 32.4 wt% MTES, approximately 3.6 wt% DMDES, and approximately 8.7 wt% organic content within the aerogel material. Metakaolin was incorporated into the sol at approximately 3.0 wt% relative to the silica content, and this was then stirred for more than 1 hour.

[0167] Guanidine hydroxide (2M) was added to the combined sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalytically activated metakaolin-containing sol was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0168] The fiber-reinforced phase was a uniform nonwoven fabric material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consisted of approximately 65 wt% aerogel and 35 wt% fiber, achieving the expected material density of approximately 0.16 to 0.20 g / cc.

[0169] (Example 8) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), are prepared independently by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel is obtained having a hydrophobic content from approximately 32.4 wt% MTES, approximately 3.6 wt% DMDES, and approximately 8.7 wt% organic content within the aerogel material. Metakaolin is incorporated into the sol at approximately 3.0 wt% relative to the silica content, and this is then stirred for at least 1 hour.

[0170] Lithium hydroxide (1.0 M) was added to the combined sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalytically activated metakaolin-containing sol was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol-aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0171] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching an expected material density of approximately 0.16 to 0.20 g / cc.

[0172] (Example 9) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), are prepared independently by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel is obtained having a hydrophobic content from approximately 28.8 wt% MTES, a DMDES content of approximately 7.2 wt%, and an organic content of approximately 9.3 wt% within the aerogel material. Metakaolin is incorporated into the sol at approximately 3.0 wt% relative to the silica content, and this is then stirred for at least 1 hour.

[0173] Guanidine hydroxide (2M) is added to the combined sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalytically activated metakaolin-containing sol is cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material is aged at 68°C for approximately 10 hours in an ethanol-aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0174] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching an expected material density of approximately 0.16 to 0.20 g / cc.

[0175] (Example 10) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), are prepared independently by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel is obtained having a hydrophobic content from approximately 28.8 wt% MTES, a DMDES content of approximately 7.2 wt%, and an organic content of approximately 9.3 wt% within the aerogel material. Metakaolin is incorporated into the sol at approximately 3.0 wt% relative to the silica content, and this is then stirred for at least 1 hour.

[0176] Lithium hydroxide (1.0 M) was added to the combined sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalytically activated metakaolin-containing sol was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol-aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0177] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching an expected material density of approximately 0.16 to 0.20 g / cc.

[0178] (Example 11) Sols of both methyltriethoxysilane and polyethyl silicate were prepared separately by hydrolysis under acidic conditions in ethanol. These sols were combined in specific relative ratios and used at specific concentrations to obtain an aerogel material having an organic content of approximately 7.0% by weight. Halloysite clay, such as Dragonite®, was incorporated into the sols at a weight percentage of at least 0.5% relative to the silica content, and this mixture was then stirred for at least one hour.

[0179] Lithium hydroxide (1.0 M) was added to the combined sol at a concentration sufficient to target an aerogel density of approximately 0.07 to 0.085 g / cc. The catalyzed sol containing halloysite clay was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0180] The fiber-reinforced phase was a uniform nonwoven fabric material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consisted of approximately 65 wt% aerogel and 35 wt% fiber, reaching the expected material density of approximately 0.16 to 0.20 g / cc (given an aerogel density of 0.07 to 0.08 g / cc).

[0181] (Example 12) Sols of both methyltriethoxysilane (MTES) and polyethyl silicate were prepared separately by hydrolysis under acidic conditions in ethanol. These sols were combined in specific relative ratios and used at specific concentrations to obtain an aerogel material having an organic content of approximately 7.0% by weight. Halloysite clay, such as Dragonite®, was incorporated into the sols at a weight percentage of at least 0.5% relative to the silica content, and this mixture was then stirred for at least one hour.

[0182] Guanidine hydroxide (2M) is added to the prepared sol at a concentration sufficient to target an aerogel density of approximately 0.07 to 0.085 g / cc. The catalyzed sol containing halloysite clay is cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material is aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0183] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching the expected material density of approximately 0.16 to 0.20 g / cc (given an aerogel density of 0.07 to 0.08 g / cc).

[0184] (Example 13) Sols of both methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) were prepared separately by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a hydrophobic content was obtained from approximately 36% by weight of MTES, and an aerogel with an organic content of approximately 8.0% by weight in the aerogel material was obtained. Halloysite clay, such as Dragonite®, was incorporated into the sol at a weight percentage of at least 0.5% relative to the silica content, and this was then stirred for at least one hour.

[0185] Guanidine hydroxide (2M) is added to the prepared sol at a concentration sufficient to achieve an aerogel density of approximately 0.07 to 0.085 g / cc. The catalyzed sol containing halloysite is cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material is aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0186] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching the expected material density of approximately 0.16 to 0.20 g / cc (given an aerogel density of 0.07 to 0.08 g / cc).

[0187] (Example 14) Individual sols of methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) were prepared separately by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a hydrophobic content was obtained from approximately 36 wt% MTES, and an aerogel with an organic content of approximately 8.0 wt% in the aerogel material was obtained. Halloysite clay, such as Dragonite®, was incorporated into the sol at a weight percentage of at least 0.5% relative to the silica content, and this was then stirred for at least 1 hour.

[0188] Lithium hydroxide (1.0 M) was added to the combined sol at a concentration sufficient to target an aerogel density of approximately 0.07 to 0.085 g / cc. The catalyzed sol containing halloysite was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0189] The fiber-reinforced phase was a uniform nonwoven fabric material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consisted of approximately 65 wt% aerogel and 35 wt% fiber, reaching the expected material density of approximately 0.16 to 0.20 g / cc (given an aerogel density of 0.07 to 0.08 g / cc).

[0190] (Example 15) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), were independently prepared by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel was obtained with a hydrophobic content of approximately 32.4 wt% MTES, approximately 3.6 wt% DMDES, and approximately 8.7 wt% organic content within the aerogel material. Halloysite clay, e.g., Dragonite®, was incorporated into the combined sol at approximately 3.0 wt% relative to the silica content, and the mixture was then stirred for at least 1 hour.

[0191] Guanidine hydroxide (2M) was added to the combined sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalyzed sol containing halloysite was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0192] The fiber-reinforced phase was a uniform nonwoven fabric material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consisted of approximately 65 wt% aerogel and 35 wt% fiber, achieving the expected material density of approximately 0.16 to 0.20 g / cc.

[0193] (Example 16) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as those containing tetraethoxysilane (TEOS), were independently prepared by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel was obtained having a hydrophobic content of approximately 32.4% by weight of MTES, approximately 3.6% by weight of DMDES, and approximately 8.7% by weight of organic content within the aerogel material. Halloysite clay, such as Dragonite®, was incorporated into the combined sols at approximately 3.0% by weight relative to the silica content, and the mixture was then stirred for at least 1 hour.

[0194] Lithium hydroxide (1.0 M) was added to the combined sol at a concentration sufficient to achieve a target aerogel density of approximately 0.0825 g / cc. The catalyzed sol containing halloysite was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0195] The fiber-reinforced phase was a uniform nonwoven fabric material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consisted of approximately 65 wt% aerogel and 35 wt% fiber, achieving the expected material density of approximately 0.16 to 0.20 g / cc.

[0196] (Example 17) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), are prepared independently by hydrolysis under acidic conditions in ethanol. The ratios and concentrations of the sol materials are adjusted to obtain a final aerogel having a hydrophobic content of approximately 32.4% by weight of MTES, approximately 3.6% by weight of DMDES, and approximately 8.7% by weight of organic content within the aerogel material. Halloysite clay, such as Dragonite®, is incorporated into the combined sols at approximately 3.0% by weight relative to the silica content, and the mixture is then stirred for at least one hour.

[0197] Guanidine hydroxide (2M) is added to the prepared sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalyzed sol containing halloysite is cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material is aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0198] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching an expected material density of approximately 0.16 to 0.20 g / cc.

[0199] (Example 18) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), were independently prepared by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel was obtained with a hydrophobic content of approximately 32.4 wt% MTES, approximately 3.6 wt% DMDES, and approximately 8.7 wt% organic content within the aerogel material. Halloysite clay, such as Dragonite®, was incorporated into the combined sol at approximately 3.0 wt% relative to the silica content, and the mixture was then stirred for at least 1 hour.

[0200] Lithium hydroxide (1.0 M) was added to the combined sol at a concentration sufficient to achieve a target aerogel density of approximately 0.0825 g / cc. The catalyzed sol containing halloysite was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0201] The fiber-reinforced phase was a uniform nonwoven fabric material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consisted of approximately 65 wt% aerogel and 35 wt% fiber, achieving the expected material density of approximately 0.16 to 0.20 g / cc.

[0202] (Example 19) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), are prepared independently by hydrolysis under acidic conditions in ethanol. The ratios and concentrations of the sol materials are adjusted to obtain a final aerogel having a hydrophobic content of approximately 28.8 wt% MTES, approximately 7.2 wt% DMDES, and approximately 9.3 wt% organic content within the aerogel material. Halloysite clay, such as Dragonite®, is incorporated into the combined sols at approximately 3.0 wt% relative to the silica content, and the mixture is then stirred for at least one hour.

[0203] Guanidine hydroxide (2M) is added to the prepared sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalyzed sol containing halloysite is cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material is aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0204] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching an expected material density of approximately 0.16 to 0.20 g / cc.

[0205] (Example 20) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), are prepared independently by hydrolysis under acidic conditions in ethanol. The ratios and concentrations of the sol materials are adjusted to obtain a final aerogel having a hydrophobic content of approximately 28.8 wt% MTES, approximately 7.2 wt% DMDES, and approximately 9.3 wt% organic content within the aerogel material. Halloysite clay, such as Dragonite®, is incorporated into the combined sols at approximately 3.0 wt% relative to the silica content, and the mixture is then stirred for at least one hour.

[0206] Lithium hydroxide (1.0 M) was added to the combined sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalyzed sol containing halloysite was cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material was aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0207] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching an expected material density of approximately 0.16 to 0.20 g / cc.

[0208] (Example 21) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), were prepared independently by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel was obtained with a hydrophobic content of approximately 28.8% by weight of MTES, approximately 7.2% of DMDES, and approximately 9.3% by weight of organic content within the aerogel material.

[0209] Guanidine hydroxide (2M) is added to the prepared sol to a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalyst sol is cast into a mold and gelled. After curing at room temperature for less than 1 hour, the aerogel monoliths are aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0210] The resulting aerogel monoliths exhibited uniform density and composition, reaching the expected material density of approximately 0.08 to 0.10 g / cc.

[0211] (Example 22) Individual sols of both methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES), as well as a sol containing tetraethoxysilane (TEOS), were prepared independently by hydrolysis under acidic conditions in ethanol. By adjusting the ratio and concentration of the sol materials, a final aerogel was obtained with a hydrophobic content of approximately 28.8% by weight of MTES, approximately 7.2% of DMDES, and approximately 9.3% by weight of organic content within the aerogel material.

[0212] Lithium hydroxide (1.0 M) was added to the prepared sol at a concentration sufficient to achieve a target aerogel density of 0.0825 g / cc. The catalyst sol was cast into a mold and allowed to gel. After curing at room temperature for less than 1 hour, the aerogel monoliths were aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel was solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0213] The resulting aerogel monoliths exhibited uniform density and composition, reaching the expected material density of approximately 0.08 to 0.10 g / cc.

[0214] (Example 23) Table 3 below shows exemplary ranges of ratios and concentrations of sol materials useful for producing aerogel compositions according to the methods of the examples described above. The compositions in Table 3 are prepared using individual sols of methyltriethoxysilane (MTES), or individual sols of MTES and dimethyldiethoxysilane (DMDES), as well as other sols containing tetraethoxysilane (TEOS) or polyethyl silicate, each of which is prepared independently by hydrolysis under acidic conditions in ethanol according to the ratios and concentrations listed in the table. Additives, such as metahaloysite or metakaolin, are incorporated into the combined sols at a weight percentage of at least 0.5% relative to the silica content, and the mixture is then stirred for at least 1 hour.

[0215] A strong base, such as lithium hydroxide or guanidine hydroxide, is added to the combined sol at a concentration sufficient to achieve the target silica density listed. The catalyzed sol is cast onto the fiber-reinforced phase and gelled. After curing at room temperature for less than 1 hour, the aerogel material is aged at 68°C for approximately 10 hours in an ethanol aging fluid with an approximate fluid-to-gel ratio of 3:1. The aged gel is solvent-extracted with supercritical CO2 and then dried at 110°C for 2 hours.

[0216] The fiber-reinforced phase is a uniform nonwoven material composed of polyester and textile-grade glass fibers (E-glass composition), with a density of approximately 1.5 ounces / square foot and a thickness of approximately 10 mm. The resulting aerogel material consists of approximately 65 wt% aerogel and 35 wt% fiber, reaching an expected material density of approximately 0.16 to 0.20 g / cc.

[0217] TIFF0007835684000004.tif120170

[0218] Where used herein, unless otherwise specified, the conjunction "and" is intended to be inclusive, and the conjunction "or" is not intended to be exclusive. For example, the phrase "or" is intended to be exclusive.

[0219] In the context describing this disclosure (particularly in the context of the claims), the terms “a,” “an,” “the,” or similar references should be construed as encompassing both singular and plural forms unless otherwise specifically indicated herein or unless clearly inconsistent with the context.

[0220] The terms “to possess,” “to have,” “to include,” and “to contain” should be interpreted as unrestricted terms (i.e., “to include but not limited to”) unless otherwise specified.

[0221] As used herein, the term “approximately” refers to the degree of deviation typical of a particular characteristic, composition, quantity, value, or parameter identified. For example, deviations based on experimental errors, measurement errors, approximation errors, calculation errors, standard deviations from mean values, and routine adjustments.

[0222] The enumeration of value ranges in this Specified is intended solely as a convenient way to refer individually to each distinct value contained within a range, unless otherwise indicated herein, and each distinct value is incorporated herein as if it were individually enumerated herein.

[0223] All methods described herein may be performed in any suitable order, unless otherwise indicated herein or unless it is clearly inconsistent with the context. The use of any examples or exemplary language presented herein (e.g., "etc.", "for example") is intended solely to better illustrate the disclosure and, unless otherwise claimed, does not limit the scope of the disclosure. Some embodiments of the present invention are shown below. [Embodiment 1] A composition, A composition comprising a silica-based aerogel containing hydrophobic silicon, wherein more than 50% of the hydrophobic silicon is bonded to one or fewer alkyl groups. [Embodiment 2] A composition, A composition that is essentially a hydrophobic silica-based aerogel and has a heat of combustion of less than 717 cal / g. [Embodiment 3] The composition according to Embodiment 1 or Embodiment 2, wherein the silica-based aerogel further comprises a surface group essentially consisting of a hydrophobic group of the formula Si-R, where R is a single methyl group. [Embodiment 4] The composition according to Embodiment 1, wherein the silica-based aerogel is not surface-treated with a hydrophobic agent. [Embodiment 5] The composition according to Embodiment 1 or Embodiment 2, wherein the composition has a water absorption rate in the range of about 5% by weight or less, 3% by weight or less, 2% by weight or less, or about 1% by weight or less. [Embodiment 6] The composition according to Embodiment 1, wherein the composition has a heat of combustion of less than 717 cal / g. [Embodiment 7] The composition according to Embodiment 1 or Embodiment 2, having a heat of combustion in the range of approximately 700 cal / g or less, approximately 650 cal / g or less, approximately 600 cal / g or less, approximately 575 cal / g or less, approximately 550 cal / g or less, approximately 500 cal / g or less, approximately 450 cal / g or less, approximately 400 cal / g or less, approximately 350 cal / g or less, approximately 300 cal / g or less, approximately 250 cal / g or less, approximately 200 cal / g or less, approximately 150 cal / g or less, approximately 100 cal / g or less, approximately 50 cal / g or less, approximately 25 cal / g or less, and approximately 10 cal / g or less. [Embodiment 8] The composition according to any one of Embodiments 1, 2, 3, or 4, wherein the composition has a heat of combustion of 250 cal / g to 600 cal / g. [Embodiment 9] The composition according to any one of Embodiments 1 to 8, wherein the composition has the initiation of thermal decomposition of a hydrophobic organic material at 350°C or higher. [Embodiment 10] The composition according to any one of Embodiments 1 to 9, wherein the composition has the initiation of thermal decomposition of a hydrophobic organic material at 400°C or higher. [Embodiment 11] The composition according to any one of Embodiments 1 to 10, wherein the composition has the initiation of thermal decomposition of a hydrophobic organic material at 500°C or higher. [Embodiment 12] The composition according to any one of Embodiments 1 to 11, wherein the silica-based aerogel has an ammonium salt content in the range of about 2000 ppm or less. [Embodiment 13] The composition according to Embodiment 12, wherein the silica-based aerogel has an ammonium salt content in the range of about 1000 ppm or less, 500 ppm or less, 200 ppm or less, or 100 ppm or less. [Embodiment 14] The composition according to any one of Embodiments 1 to 13, wherein the silica-based aerogel has an ammonium salt content in the range of about 0.2% by weight or less. [Embodiment 15] The composition according to any one of Embodiments 1 to 14, wherein the silica-based aerogel has an ammonium salt content in the range of about 0.1% by weight or less. [Embodiment 16] The composition according to any one of Embodiments 1 to 15, wherein the silica-based aerogel has a water absorption rate in the range of about 10% by weight or less, about 8% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, or about 0.1% by weight or less. [Embodiment 17] The composition according to any one of embodiments 1 to 16, wherein the silica-based aerogel has a thermal conductivity of less than about 45 mW / M*K. [Embodiment 18] The composition according to Embodiment 17, wherein the silica-based aerogel has a thermal conductivity of approximately 45 mW / M*K or less, approximately 40 mW / M*K or less, approximately 35 mW / M*K or less, approximately 30 mW / M*K or less, approximately 25 mW / M*K or less, approximately 20 mW / M*K or less, approximately 18 mW / M*K or less, approximately 16 mW / M*K or less, approximately 15 mW / M*K or less, approximately 14 mW / M*K or less, approximately 13 mW / M*K or less, approximately 12 mW / M*K or less, or in the range of approximately 5 mW / M*K to 50 mW / M*K. [Embodiment 19] A composition according to any one of embodiments 1 to 18, further comprising a reinforcing material. [Embodiment 20] The composition according to Embodiment 19, wherein the reinforcing material includes a fiber-reinforced material or a foam-reinforced material. [Embodiment 21] The composition according to any one of embodiments 1 to 20, further comprising an opacifying or fire-class additive. [Embodiment 22] The composition according to Embodiment 21, wherein the opacifying or fire-class additive is present in an amount ranging from about 0.1% by weight to about 10% by weight. [Embodiment 23] The composition according to Embodiment 21, wherein the opacifying or fire-class additive is present in an amount ranging from about 0.5% by weight to about 3.0% by weight. [Embodiment 24] The aforementioned opacifying or fire-class additives include boron carbide, diatomaceous earth, manganese ferrite, manganese oxide, nickel oxide, tin oxide, silver oxide, bismuth oxide, titanium carbide, tungsten carbide, carbon black, titanium oxide, iron oxide, zirconium silicate, zirconium oxide, iron oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, iron oxide, chromium oxide, silicon carbide, phyllosilicate clay, kaolin or kaolinite, metakaolin, halloysite, metahaloysite, enderite, mica, diaspore, gibbsite, boehmite, montmorillonite, and beiderei. The composition according to Embodiment 21, selected from the group consisting of pyrophyllite, nontronite, brabiite, smectite, lebrierite, rectolite, celadonite, attapulgite, chloropar, volconscoite, allofen, racewinite, dillnite, severite, miroskite, corylite, simolite and newtonite, sodium bicarbonate, magnesium hydroxide, magnesium dihydrate, alumina trihydrate, gypsum, valintonite, neskehonite, lancefordite, hydromagnesite, dolomite, lithium carbonate, or mixtures thereof. [Embodiment 25] The composition according to any one of Embodiments 1 to 24, further comprising at least about 0.1% by weight of a strong base or a strong base derivative. [Embodiment 26] A composition according to any one of Embodiments 1 to 25, comprising up to approximately 2% by weight of a strong base or a strong base derivative. [Embodiment 27] The composition according to Embodiment 24 or Embodiment 25, wherein the strong base or strong base derivative comprises a cation selected from the group consisting of lithium, calcium, sodium, potassium, rubidium, barium, strontium, and guanidinium. [Embodiment 28] A composition comprising a silica-based aerogel, comprising at least about 0.1% by weight of a strong base or a strong base derivative. [Embodiment 29] The composition according to Embodiment 28, comprising up to about 2% by weight of a strong base or a strong base derivative. [Embodiment 30] The composition according to Embodiment 28 or Embodiment 29, wherein the strong base or strong base derivative comprises a cation selected from the group consisting of lithium, calcium, sodium, potassium, rubidium, barium, strontium, and guanidinium. [Embodiment 31] The composition according to any one of embodiments 28 to 30, wherein the silica-based aerogel contains hydrophobic-bonded silicon, and more than 50% of the hydrophobic-bonded silicon is bonded to a single alkyl group. [Embodiment 32] A composition according to any one of embodiments 28 to 31, having a water absorption rate in the range of approximately 15% by weight or less, a heat of combustion of less than 717 cal / g, and an initiation of thermal decomposition of hydrophobic organic materials at 400°C or higher. [Embodiment 33] It is a method, Prepare a precursor solution containing silica gel precursor material and solvent. Prepare a basic catalyst solution having a pKb of less than approximately 4. Combining the precursor solution and the basic catalyst solution, Transferring the silica precursor material to a gel composition, A method comprising extracting at least a portion of the solvent from the gel composition to obtain a silica-based aerogel composition. [Embodiment 34] The method according to Embodiment 33, wherein the precursor solution comprises at least one silica gel precursor material having at least one hydrophobic group. [Embodiment 35] The method according to Embodiment 33 or Embodiment 34, wherein the precursor solution contains more than 30% of at least one silica gel precursor material having a single alkyl group bonded to silicon. [Embodiment 36] The method according to either embodiment 33 or 34, wherein the precursor solution contains more than 30% of at least one silica gel precursor material having a single methyl group bonded to silicon. [Embodiment 37] The method according to any one of embodiments 33 to 36, wherein the gel composition is not surface-treated with a hydrophobic agent. [Embodiment 38] The method according to any one of embodiments 33 to 37, wherein the basic catalyst comprises a catalytic amount of a strong base selected from the group consisting of sodium hydroxide, lithium hydroxide, calcium hydroxide, potassium hydroxide, strontium hydroxide, barium hydroxide, guanidine hydroxide, sodium hydroxide, tetrabutylammonium hydroxide, tetramethylammonium hydroxide, choline hydroxide, phosphonium hydroxide, DABCO, DBU, guanidine derivatives, amidine, and phosphazene. [Embodiment 39] The method according to any one of embodiments 33 to 38, further comprising incorporating a reinforcing material into the silica-based aerogel composition. [Embodiment 40] The method according to any one of Embodiment 39, further comprising incorporating an additive into the silica-based aerogel composition. [Embodiment 41] The method according to Embodiment 40, wherein the additive is present in an amount ranging from about 0.1% to about 10% by weight of the silica-based aerogel composition. [Embodiment 42] The method according to Embodiment 41, wherein the additive is present in an amount ranging from about 0.5% by weight to about 3% by weight. [Embodiment 43] The aforementioned additives include boron carbide, diatomaceous earth, manganese ferrite, manganese oxide, nickel oxide, tin oxide, silver oxide, bismuth oxide, titanium carbide, tungsten carbide, carbon black, titanium oxide, iron oxide, zirconium silicate, zirconium oxide, iron oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, iron oxide (ilmenite), chromium oxide, silicon carbide, phyllosilicate clay, kaolin or kaolinite, metakaolin, halloysite, metahaloysite, enderite, mica, diaspore, gibbsite, boehmite, montmorillonite, beiderite, pyrophila The method according to any one of embodiments 40 to 42, selected from the group consisting of litho, nontronite, brabiite, smectite, lebrierite, rectolite, celadonite, attapulgite, chloropar, volconscoite, allofen, racewinite, dillnite, severite, myroskite, corylite, simolite and newtonite, sodium bicarbonate, magnesium hydroxide, magnesium dihydrate, alumina trihydrate, gypsum, valintonite, neskehonite, lancefoldite, hydromagnesite, dolomite, lithium carbonate, or mixtures thereof.

Claims

1. A composition comprising a silica-based aerogel containing hydrophobic-bonded silicon, The silica-based aerogel contains a guanidinium cation. A composition wherein the silica-based aerogel is not surface-treated with a hydrophobic agent.

2. The composition according to claim 1, wherein the silica-based aerogel comprises a surface group consisting of a hydrophobic group of the formula Si-R, where R is a single alkyl group.

3. The composition according to claim 2, wherein R is a single methyl group.

4. The composition according to claim 1, wherein the composition has a heat of combustion of less than 717 cal / g.

5. The composition according to claim 1, wherein the composition has a heat of combustion in the range of 700 cal / g or less, 650 cal / g or less, 600 cal / g or less, 575 cal / g or less, 550 cal / g or less, 500 cal / g or less, 450 cal / g or less, 400 cal / g or less, 350 cal / g or less, 300 cal / g or less, 250 cal / g or less, 200 cal / g or less, 150 cal / g or less, 100 cal / g or less, 50 cal / g or less, 25 cal / g or less, and 10 cal / g or less.

6. The composition according to claim 1, wherein the composition has a heat of combustion of 250 cal / g to 600 cal / g.

7. The composition according to claim 1, wherein the thermal decomposition of the hydrophobic organic material begins at 350°C or higher.

8. The composition according to claim 1, wherein the thermal decomposition of the hydrophobic organic material begins at 400°C or higher.

9. The composition according to claim 1, wherein the thermal decomposition of the hydrophobic organic material at 500°C or higher begins at 500°C or higher.

10. The composition according to claim 1, wherein the silica-based aerogel has a thermal conductivity of less than 45 mW / M*K.

11. The composition according to claim 10, wherein the silica-based aerogel has a thermal conductivity of 40 mW / M*K or less, 35 mW / M*K or less, 30 mW / M*K or less, 25 mW / M*K or less, 20 mW / M*K or less, 18 mW / M*K or less, 16 mW / M*K or less, 15 mW / M*K or less, 14 mW / M*K or less, 13 mW / M*K or less, or 12 mW / M*K or less.

12. The composition according to claim 1, further comprising a reinforcing material.

13. The composition according to claim 12, wherein the reinforcing material includes a fiber reinforcing material or a foam reinforcing material.

14. The composition according to claim 1, further comprising an opacifying or fire-class additive.

15. The composition according to claim 14, wherein the opacifying or fire-class additive is present in an amount ranging from 0.1% by weight to 10% by weight.

16. The composition according to claim 14, wherein the opacifying or fire-class additive is present in an amount ranging from 0.5% by weight to 3.0% by weight.

17. The aforementioned opacifying or fire-class additives include boron carbide, diatomaceous earth, manganese ferrite, manganese oxide, nickel oxide, tin oxide, silver oxide, bismuth oxide, titanium carbide, tungsten carbide, carbon black, titanium oxide, iron oxide, zirconium silicate, zirconium oxide, iron oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, iron oxide, chromium oxide, silicon carbide, phyllosilicate clay, kaolin or kaolinite, metakaolin, halloysite, metahaloysite, enderite, mica, diaspore, gibbsite, boehmite, montmorillonite, and beiderei. The composition according to claim 14, selected from the group consisting of pyrophyllite, nontronite, brabiite, smectite, lebrierite, rectolite, celadonite, attapulgite, chloropar, volconscoite, allofen, racewinite, dillnite, severite, myroskite, corylite, simolite and newtonite, sodium bicarbonate, magnesium hydroxide, magnesium dihydrate, alumina trihydrate, gypsum, valintonite, neskehonite, lancefordite, hydromagnesite, dolomite, lithium carbonate, or mixtures thereof.

18. The composition according to claim 1, wherein the guanidinium cation is present in an amount of at least 0.1% by weight.

19. The composition according to claim 1, comprising up to 2% by weight of guanidinium cations.

20. Prepare a precursor solution containing silica gel precursor material and solvent; Prepare a basic catalyst solution, where the basic catalyst is a catalytic amount of guanidine hydroxide; Combining the precursor solution and the basic catalyst solution; Transferring the silica gel precursor material to a gel composition; and Extracting at least a portion of the solvent from the gel composition to obtain a silica-based aerogel composition; Includes, The gel composition is hydrophobic without surface modification by a hydrophobic agent. method.

21. The method according to claim 20, wherein the precursor solution comprises at least one silica gel precursor material having at least one hydrophobic group.

22. The method according to claim 20, wherein the precursor solution contains more than 30% of at least one silica gel precursor material which is an alkylsilane having only one alkyl group bonded to silicon.

23. The method according to claim 22, wherein the single alkyl group is a methyl group.

24. The method according to claim 20, further comprising incorporating a reinforcing material into the silica-based aerogel composition.

25. The method according to claim 24, further comprising incorporating an additive into the silica-based aerogel composition.

26. The method according to claim 25, wherein the additive is present in an amount of 0.1% to 10% by weight of the silica-based aerogel composition.

27. The method according to claim 26, wherein the additive is present in an amount ranging from 0.5% by weight to 3% by weight.

28. The aforementioned additives include boron carbide, diatomaceous earth, manganese ferrite, manganese oxide, nickel oxide, tin oxide, silver oxide, bismuth oxide, titanium carbide, tungsten carbide, carbon black, titanium oxide, iron oxide, titanium iron oxide, zirconium silicate, zirconium oxide, iron oxide, iron(II) oxide, iron(III) oxide, manganese dioxide, iron oxide (ilmenite), chromium oxide, silicon carbide, phyllosilicate clay, kaolin or kaolinite, metakaolin, halloysite, metahaloysite, enderite, mica, diaspore, gibbsite, boehmite, montmorillonite, beiderite, and The method according to claim 25, selected from the group consisting of ilophyllite, nontronite, brabiite, smectite, lebrierite, rectolite, celadonite, attapulgite, chloropar, volconscoite, allofen, racewinite, dillnite, severite, myrosskite, corylite, simolite and newtonite, sodium bicarbonate, magnesium hydroxide, magnesium dihydrate, alumina trihydrate, gypsum, valintonite, neskehonite, lancefordite, hydromagnesite, dolomite, lithium carbonate, or mixtures thereof.

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