Organic silicon aerogel composite material as well as preparation method and application thereof

Abstract

The invention discloses an organic silicon aerogel composite material as well as a preparation method and application thereof, belongs to the technical field of heat prevention and insulation materials, and solves the problems that a heat prevention and insulation material in the prior art cannot have high strength and excellent ablation resistance at the same time, the preparation process is complicated, and the cost is high. The preparation method of the organic silicon aerogel composite material provided by the invention comprises the following steps: reacting a first silane monomer containing amino / sulfydryl with a polymer monomer to prepare a carbon-rich precursor, carrying out first gel reaction, aging and drying to obtain a carbon-rich skeleton with excellent mechanical properties; then, a silicon-rich precursor is prepared from a second silane monomer and is secondarily impregnated into the carbon-rich composite material, in the process, the silane monomer is subjected to auto-polymerization, a silicon-rich network skeleton with excellent thermodynamic properties is formed in gaps of a skeleton of the carbon-rich composite material, and a unique interpenetrating double-network structure is formed; the mechanical property and ablation resistance of the prepared composite material are remarkably improved, and good application in the field of thermal insulation materials is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat-insulating materials, and in particular to an organosilicon aerogel composite material and a preparation method and application thereof. Background Art

[0002] As a material with a three-dimensional nanoporous network structure, silica aerogel has shown great application potential in thermal protection, thermal insulation and other fields due to its advantages such as low density, low thermal conductivity and good hydrophobicity. However, its inherent brittleness and porous structure lead to its poor mechanical strength, which greatly limits its practical application. To solve this problem, traditional methods either sacrifice the excellent thermal stability and ablation resistance of the material itself or use costly and complex preparation processes.

[0003] CN119462067A discloses an aerogel composite material prepared by multiple impregnations. The material has a strength range of 4.05-14.19 MPa at 3% compression deformation and a thermal conductivity of 0.045-0.089 W / m·K at room temperature. It has excellent mechanical strength and high-temperature resistance. However, the material requires supercritical drying technology during the drying process, which is costly. Moreover, the tensile strength of the composite material prepared using this method is predictably relatively low.

[0004] CN111892729A discloses an aerogel material prepared by free radical polymerization of unsaturated silane monomers under the action of an initiator. The material has the characteristics of flexibility and high strength and does not require a complicated drying process, but loses the excellent thermodynamic properties of the aerogel itself.

[0005] Due to the low strength of silica aerogel, existing preparation methods usually use expensive and complex solvent exchange and supercritical drying technologies when drying the material, or sacrifice some of the thermodynamic properties of the aerogel itself, and cannot achieve high strength, excellent thermodynamic properties and low-cost preparation methods at the same time.

[0006] Therefore, developing a silicone aerogel composite material that can achieve synergistic high strength and ablation resistance while adopting a more economical and simple preparation process is of great significance for promoting its practical engineering application. Summary of the Invention

[0007] In view of the above situation, the present invention aims to provide an organosilicon aerogel composite material and its preparation method and application, which are used to solve at least one of the following technical problems: existing organosilicon aerogel composite materials cannot have both high strength and excellent ablation resistance, and the preparation process is complex and the cost is high.

[0008] The purpose of the present invention is mainly achieved through the following technical solutions:

[0009] A first aspect of the present invention provides a method for preparing an organosilicon aerogel composite material, comprising the following steps:

[0010] S1, mixing a first silane monomer, a polymer monomer, and an alcohol solvent to obtain a first mixed solution, performing a first sol reaction, and obtaining a carbon-rich precursor solution; mixing a second silane monomer and an alcohol solvent to obtain a second mixed solution, and performing a second sol reaction, and obtaining a silicon-rich precursor solution;

[0011] S2-1. Under sealed conditions, the fiber preform is initially impregnated with the carbon-rich precursor solution, followed by a first gelation reaction to obtain a carbon-rich composite material. Alternatively, S2-2. Under sealed conditions, the fiber preform is initially impregnated with the silicon-rich precursor solution, followed by a first gelation reaction to obtain a silicon-rich composite material.

[0012] S3-1, under sealed conditions, contacting the carbon-rich composite material with the silicon-rich precursor solution for secondary impregnation, and then undergoing a second gelation reaction; or, S3-2, under sealed conditions, contacting the silicon-rich composite material with the carbon-rich precursor solution for secondary impregnation, and then undergoing a second gelation reaction;

[0013] An organosilicon aerogel composite material is obtained; wherein the first silane monomer has a structure shown in Formula A:

[0014]

[0015] n is an integer between 2 and 6, R A1 Selected from amino or thiol, R A2 is selected from C1-C4 alkyl or C1-C4 alkoxy, R A3 and R A4 Each independently selected from C1-C4 alkoxy;

[0016] The second silane monomer has a structure shown in Formula B:

[0017]

[0018] R B1 is selected from C2-C4 alkenyl, aryl or C1-C4 alkoxy, R B2 、R B3 and R B4 Each is independently selected from C1-C4 alkoxy.

[0019] Furthermore, the first silane monomer is selected from 3-aminopropyl alkoxysilane and / or 3-mercaptopropyl alkoxysilane.

[0020] Furthermore, the polymer monomer is selected from glycidyl ether and / or isocyanate.

[0021] Furthermore, the second silane monomer is selected from at least one of vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, tetramethoxysilane and tetraethoxysilane.

[0022] Furthermore, the fiber preform is woven from organic fibers and / or inorganic fibers.

[0023] Furthermore, the density of the fiber preform is 0.1-0.5 g / cm 3 .

[0024] Furthermore, in step S1, in the first mixed solution, the mass ratio of the first silane monomer to the polymer monomer is (1-4):(1-4).

[0025] Furthermore, in the first mixed solution, the sum of the mass of the first silane monomer and the polymer monomer accounts for 20-60% of the total mass of the first mixed solution.

[0026] Furthermore, the mass of the second silane monomer in the second mixed solution accounts for 20-60% of the total mass of the second mixed solution.

[0027] Furthermore, the first sol reaction step includes: adding deionized water to the first mixed solution at room temperature, stirring for 30-60 minutes, and then adding an alkaline catalyst and continuing to stir for 5-15 minutes to obtain a carbon-rich precursor solution.

[0028] Furthermore, at room temperature, the second sol reaction step includes: adding an acidic catalyst to the second mixed solution, stirring and mixing uniformly, then adding deionized water, stirring for 30-60 minutes, and then adding an alkaline catalyst and continuing to stir for 5-15 minutes to obtain a silicon-rich precursor solution.

[0029] Furthermore, the first impregnation and the second impregnation are performed under pressurized or vacuum conditions.

[0030] Furthermore, the pressurization condition includes: a pressure of 1-3 bar, and the vacuum condition includes: a pressure of 0-1 bar.

[0031] Furthermore, the conditions of the first gel reaction and the second gel reaction independently include: a reaction temperature of 40-120° C., and a reaction time of 24-48 hours.

[0032] Furthermore, the method further comprises: performing a first aging and a first drying on the gel product obtained after the first gel reaction; and performing a second aging and a second drying on the gel product obtained after the second gel reaction.

[0033] Furthermore, the conditions of the first aging and the second aging each independently include: standing the gel product at 100-120° C. for 6-10 hours.

[0034] Furthermore, the conditions for the first drying and the second drying each independently include: drying at 20-120° C. for 1-5 days.

[0035] The second aspect of the present invention provides an organosilicon aerogel composite material prepared by the preparation method described in the first aspect of the present invention.

[0036] Furthermore, the organosilicon aerogel composite material includes an organosilicon aerogel matrix and a reinforcement phase, the matrix comprises a carbon-rich skeleton and a silicon-rich skeleton having an interpenetrating network structure, and the reinforcement phase includes a fiber preform.

[0037] Furthermore, in the organosilicon aerogel matrix, the mass ratio of the carbon-rich skeleton to the silicon-rich skeleton is (1-4):(1-4).

[0038] Furthermore, the average pore size of the organosilicon aerogel composite material is 130-280 mm, the porosity is 40-76%, and the density is 0.51-0.6 g / cm 3 .

[0039] The third aspect of the present invention provides an application of the organosilicon aerogel composite material described in the second aspect of the present invention in the field of high-temperature heat insulation.

[0040] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0041] (1) The present invention adopts a carbon-rich precursor and a silicon-rich precursor to collaboratively construct an interpenetrating network structure. The carbon-rich precursor first constructs a high-strength skeleton structure and then generates an ablation-resistant silicon-rich network skeleton in the pores of the carbon-rich skeleton by a secondary impregnation method. Alternatively, the silicon-rich precursor first constructs a skeleton structure with high ablation resistance and then generates a high-strength carbon-rich network skeleton in the pores of the silicon-rich skeleton by a secondary impregnation method, thereby achieving the synergy of high strength and excellent ablation resistance of the composite material.

[0042] (2) The present invention first uses a first silane monomer containing an amino group / thiol group and a polymer monomer as raw materials to prepare a carbon-rich precursor. During this process, the amino group or thiol group in the silane monomer reacts with the polymer monomer to obtain a carbon-rich network skeleton with a high degree of cross-linking and excellent mechanical properties. Then, the silane monomer is used as a raw material to prepare a silicon-rich precursor. During this process, the silane monomer self-polymerizes to form a silicon-rich network skeleton with low thermal conductivity, so that the composite material has better ablation resistance.

[0043] (3) The present invention adopts the process of secondary impregnation, RTM molding, and atmospheric pressure drying to prepare a high-strength, ablation-resistant organic silicon aerogel composite material with a density of 0.51-0.6 g / cm 3 , tensile strength is not less than 17MPa, room temperature thermal conductivity is not higher than 0.06W / (m·K), mass ablation rate is not higher than 0.52×10 -3 g / s, the linear ablation rate is not higher than 2.64×10 - 3 mm / s.

[0044] (4) In the present invention, it is preferred to first prepare a high-strength carbon-rich skeleton structure and then generate an ablation-resistant silicon-rich network skeleton in the pores of the carbon-rich skeleton by secondary impregnation. This preparation method can avoid damaging the previously prepared silicon-rich skeleton, which may damage the integrity of the structure, because the skeleton of the carbon-rich composite material is thicker than that of the silicon-rich composite material. Therefore, the skeleton structure of the composite material is more complete and the mechanical properties are higher. The tensile strength of the composite material can reach 41.4 MPa, and it has better comprehensive performance.

[0045] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some of the advantages will become apparent from the description, or will be understood by practicing the present invention. The objects and other advantages of the present invention can be realized and obtained by the contents particularly pointed out in the description and the drawings. Other features and advantages of the present invention will be described in the subsequent description, and some of them will become apparent from the description, or will be understood by practicing the present invention. The objects and other advantages of the present invention can be realized and obtained by the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0047] Figure 1 This is a photo of the organosilicon aerogel composite material prepared in Example 1;

[0048] Figure 2 This is a scanning electron microscope image of the carbon-rich skeleton and the silicon-rich skeleton in the organosilicon aerogel composite material prepared in Example 1;

[0049] Figure 3 1 is the tensile stress-strain curve of the organosilicon aerogel composite material prepared in Examples 1-3;

[0050] Figure 4 This is the thermogravimetric analysis curve of the organosilicon aerogel matrix in the organosilicon aerogel composite material prepared in Examples 1-3. DETAILED DESCRIPTION

[0051] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used to explain the principles of the present invention together with the embodiments of the present invention.

[0052] A first aspect of the present invention provides a method for preparing an organosilicon aerogel composite material, comprising the following steps:

[0053] S1, mixing a first silane monomer, a polymer monomer, and an alcohol solvent to obtain a first mixed solution, performing a first sol reaction, and obtaining a carbon-rich precursor solution; mixing a second silane monomer and an alcohol solvent to obtain a second mixed solution, and performing a second sol reaction, and obtaining a silicon-rich precursor solution;

[0054] S2-1. Under sealed conditions, the fiber preform is initially impregnated with the carbon-rich precursor solution, followed by a first gelation reaction to obtain a carbon-rich composite material. Alternatively, S2-2. Under sealed conditions, the fiber preform is initially impregnated with the silicon-rich precursor solution, followed by a first gelation reaction to obtain a silicon-rich composite material.

[0055] S3-1, under sealed conditions, contacting the carbon-rich composite material with the silicon-rich precursor solution for secondary impregnation, and then undergoing a second gelation reaction; or, S3-2, under sealed conditions, contacting the silicon-rich composite material with the carbon-rich precursor solution for secondary impregnation, and then undergoing a second gelation reaction;

[0056] obtaining an organosilicon aerogel composite material;

[0057] Wherein, the first silane monomer has a structure shown in Formula A:

[0058]

[0059] n is an integer between 2 and 6, R A1 Selected from amino or thiol, R A2 is selected from C1-C4 alkyl or C1-C4 alkoxy, R A3 and R A4Each independently selected from C1-C4 alkoxy;

[0060] The second silane monomer has a structure shown in Formula B:

[0061]

[0062] R B1 is selected from C2-C4 alkenyl, aryl or C1-C4 alkoxy, R B2 、R B3 and R B4 Each is independently selected from C1-C4 alkoxy.

[0063] According to a particularly preferred embodiment of the present invention, the first silane monomer is selected from 3-aminopropylalkoxysilane and / or 3-mercaptopropylalkoxysilane, such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropylethyldimethoxysilane, 3-aminopropylethyldiethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropylethyldimethoxysilane, and 3-mercaptopropylethyldiethoxysilane.

[0064] According to a preferred embodiment of the present invention, the polymer monomer is selected from glycidyl ether and / or isocyanate.

[0065] According to a particularly preferred embodiment of the present invention, the glycidyl ether is at least one selected from resorcinol diglycidyl ether, ethylene glycol diglycidyl ether and diglycidyl ether.

[0066] According to a particularly preferred embodiment of the present invention, the isocyanate is at least one selected from toluene diisocyanate, hexamethylene diisocyanate and diphenylmethane diisocyanate.

[0067] In the present invention, when the type of polymer monomer meets the above requirements, it can further react with the amino group or mercapto group in the first silane monomer to obtain a high-strength carbon-rich skeleton.

[0068] According to a particularly preferred embodiment of the present invention, the second silane monomer is selected from at least one of vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, tetramethoxysilane and tetraethoxysilane.

[0069] According to the present invention, the fiber preform is woven from organic fibers and / or inorganic fibers.

[0070] Specifically, considering that the final organic silicon aerogel composite material can have both lightness and high mechanical strength, the density of the fiber preform is 0.1-0.5 g / cm 3 More than 0.5g / cm 3 This will lead to meeting the demand for lightweight silicone aerogel composite materials; less than 0.1g / cm 3 This will result in a decrease in the mechanical strength of the silicone aerogel composite material. In the field of high-temperature thermal insulation, its application is limited because the mechanical strength does not meet the requirements.

[0071] According to a particularly preferred embodiment of the present invention, the organic fiber includes at least one of polyacrylonitrile pre-oxidized silk fiber, viscose-based fiber, biomass fiber and phenolic fiber.

[0072] According to a particularly preferred embodiment of the present invention, the inorganic fiber includes at least one of quartz fiber, glass fiber and alumina fiber.

[0073] In the present invention, in the above step S1, the type of the alcohol solvent is not specifically limited, and for example, it can be at least one selected from methanol, ethanol, isopropanol and benzyl alcohol.

[0074] According to the present invention, taking into account that the amino group or thiol group in the first silane monomer and the epoxy group or isocyanate group in the polymer monomer can fully react, in the above step S1, the mass ratio of the first silane monomer to the polymer monomer in the first mixed solution is (1-4): (1-4), for example, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:4, 2:1, 2:2.2, 2:2.5, 2:3.5, 3.5:2.5, 3:4 and a range consisting of any two of the above values.

[0075] In order to further obtain better technical effects, in the first mixed solution, the mass ratio of the first silane monomer and the polymer monomer is (1-2):(1-2), for example, 1:1, 1:1.2, 1:1.4, 1:1.8, 1:2, 1.5:2, 1.75:1.25, 2:1 and a range consisting of any two of the above values.

[0076] In the present invention, the first silane monomer contains a long carbon chain structure and can react with the polymer monomer to obtain a high-strength carbon-rich skeleton. When the mass ratio of the first silane monomer to the polymer monomer meets the above requirements, the mechanical strength of the carbon-rich skeleton can be further improved.

[0077] According to the present invention, the inventors unexpectedly discovered that in the above-mentioned step S1, the sum of the mass of the first silane monomer and the polymer monomer in the first mixed solution accounts for 20-60% of the total mass of the first mixed solution, for example, 20%, 22%, 23%, 25%, 26%, 28%, 30%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60%, and a range consisting of any two of the above values, which can enable the final silicone aerogel composite material to have both excellent mechanical properties and ablation resistance. If it is less than 20%, the mechanical strength of the final silicone aerogel composite material will be poor and the thermodynamic properties will be reduced. If it is greater than 60%, the compatibility of the solution system is too poor, which is not conducive to the full progress of the reaction, and the mechanical strength and thermodynamic properties of the final silicone aerogel composite material will also be reduced.

[0078] In the present invention, in order to further obtain better technical effects, the sum of the masses of the first silane monomer and the polymer monomer accounts for 20-35% of the total mass of the first mixed solution, such as 20%, 22%, 23%, 25%, 26%, 28%, 30%, 35% and the range consisting of any two of the above values.

[0079] Specifically, the step of the first sol reaction includes: adding deionized water to the first mixed solution, stirring for 30-60 minutes, for example, 30 minutes, 35 minutes, 38 minutes, 40 minutes, 42 minutes, 45 minutes, 47 minutes, 50 minutes, 55 minutes, 60 minutes and the range consisting of any two of the above values, and then adding an alkaline catalyst and continuing to stir for 5-15 minutes, for example, 5 minutes, 6 minutes, 6.8 minutes, 7 minutes, 7.5 minutes, 8 minutes, 9 minutes, 10 minutes, 12 minutes, 14 minutes, 15 minutes and the range consisting of any two of the above values ​​to obtain a carbon-rich precursor solution.

[0080] Specifically, the amount of deionized water added in the preparation of the carbon-rich precursor solution in step S1 is related to the type of the first silane monomer, that is, the amount of deionized water added is 1-2 times the molar amount of the active functional group in the first silane monomer, and the stirring time is 30-60 min, such as 30 min, 35 min, 38 min, 40 min, 42 min, 45 min, 47 min, 50 min, 55 min, 60 min and the range composed of any two of the above values, so that sufficient hydrolysis can be ensured. The amount of the alkaline catalyst added is 0.1-1% of the total mass of the first mixed solution, and the stirring time is 5-15 min, such as 5 min, 6 min, 6.8 min, 7 min, 7.5 min, 8 min, 9 min, 10 min, 12 min, 14 min, 15 min and the range composed of any two of the above values, so that the solution system can form a sol system, providing a basis for the subsequent preparation of a carbon-rich composite material with high mechanical strength.

[0081] It is understood that the active functional group refers to an alkoxy group.

[0082] In the present invention, the amino group and the mercapto group in the first silane monomer can make the precursor solution alkaline and acidic respectively, so no additional catalyst is required during hydrolysis.

[0083] Exemplarily, the alkaline catalyst can be tetramethylammonium hydroxide (25wt% methanol solution) or ammonia water. Wherein, 25wt% methanol solution means that per 100 grams of solution, it contains 25 grams of tetramethylammonium hydroxide and the remaining 75 grams is methanol as a solvent. The amount of the alkaline catalyst (calculated as tetramethylammonium hydroxide) can be 0.1-1% of the mass of the first mixed solution, for example, 0.1%, 0.2%, 0.29%, 0.37%, 0.5%, 0.6%, 0.68%, 0.8%, 0.85%, 0.9%, 1% and a range consisting of any two of the above values.

[0084] Specifically, the pH value of the reaction system is in the range of 7-10 to ensure that the gel reaction proceeds fully, so that the first mixed solution forms a gel-like substance with good elasticity. When touched or lightly pressed by hand, obvious rebound force can be felt and it will not easily break or deform.

[0085] In the present invention, the inventors have found through extensive research that by controlling the types of first silane monomers and polymer monomers with specific structures, the mass ratio of the first silane monomers and polymer monomers, and the mass fraction of the solute in the carbon-rich precursor solution, the above requirements can be met, thereby making the subsequently prepared carbon-rich composite material have excellent mechanical stability, and at the same time can synergistically improve the thermodynamic properties of the subsequent silicon-rich skeleton.

[0086] According to the present invention, the inventors unexpectedly discovered that in the above-mentioned step S1, the mass of the second silane monomer in the second mixed solution accounts for 20-60% of the total mass of the second mixed solution, for example, 20%, 22%, 23%, 25%, 26%, 28%, 30%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60% and a range consisting of any two of the above values, which can make the final organic silicon aerogel composite material have excellent ablation resistance and mechanical properties. If it is less than 20%, the thermodynamic properties of the final organic silicon aerogel composite material will be poor and the mechanical strength will be reduced. If it is greater than 60%, the compatibility of the solution system is too poor to be conducive to the full progress of the reaction, which will also reduce the thermodynamic properties and mechanical strength of the final organic silicon aerogel composite material.

[0087] In the present invention, to further achieve better technical effects, in the second mixed solution, the mass of the second silane monomer accounts for 20-60% of the total mass of the first mixed solution, for example, 20%, 22%, 23%, 25%, 26%, 28%, 30%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60%, or a range consisting of any two of the above values, preferably 25-40%.

[0088] Specifically, the second sol reaction step includes: adding an acidic catalyst dropwise to the second mixed solution, stirring and mixing uniformly, then adding deionized water, stirring for 30-60 minutes, and then adding an alkaline catalyst and continuing to stir for 5-15 minutes to obtain a silicon-rich precursor solution.

[0089] Specifically, the amount of deionized water added to the second sol reaction is related to the type of the second silane monomer, that is, the amount of deionized water added is 1-2 times the molar amount of the alkoxy group in the second silane monomer. Simultaneously, the amount of the acidic catalyst added is 1-3% of the total mass of the second mixed solution, and the stirring time is 30-60 minutes, thereby ensuring sufficient hydrolysis. The amount of the alkaline catalyst added is 0.1-1% of the total mass of the second mixed solution, thereby ensuring that the solution system forms a gel system. This, combined with the aforementioned method for preparing a carbon-rich composite material, provides a foundation for the subsequent preparation of an organosilicon aerogel composite material with both ablation resistance and high mechanical strength.

[0090] Exemplarily, the acidic catalyst can be at least one of formic acid, acetic acid and oxalic acid, and the amount of the acidic catalyst can be 1-3% of the mass of the second mixed solution, and the pH value of the system is 3-7. Exemplarily, the basic catalyst can be tetramethylammonium hydroxide (25wt% methanol solution) or ammonia water. The amount of the basic catalyst can be 0.5-1.5% of the mass of the second mixed solution. The pH value of the reaction system is in the range of 7-10 to ensure that the gel reaction is fully carried out, so that the first mixed solution forms a gel-like substance with good elasticity. When touched or lightly pressed by hand, obvious resilience can be felt, and it will not easily break or deform.

[0091] In the present invention, both the first sol reaction and the second sol reaction can be carried out at room temperature. For example, the room temperature can be 18-30°C.

[0092] In the present invention, the viscosity of the carbon-rich precursor solution obtained after the first sol reaction at 25°C is 10-100 mPa·s, for example, 10 mPa·s, 15 mPa·s, 20 mPa·s, 25 mPa·s, 30 mPa·s, 35 mPa·s, 40 mPa·s, 48 ​​mPa·s, 50 mPa·s, 60 mPa·s, 70 mPa·s, 80 mPa·s, 85 mPa·s, 90 mPa·s, 95 mPa·s, 98 mPa·s, 100 mPa·s, or any two of the above values. Range: The viscosity of the silicon-rich precursor solution obtained after the reaction of the second sol at 25°C is 10-100mpa·s, for example, 10mpa·s, 15mpa·s, 20mpa·s, 25mpa·s, 30mpa·s, 35mpa·s, 40mpa·s, 48mpa·s, 50mpa·s, 60mpa·s, 70mpa·s, 80mpa·s, 85mpa·s, 90mpa·s, 95mpa·s, 98mpa·s, 100mpa·s and the range consisting of any two of the above values.

[0093] Specifically, in the above step S2-1, the fiber preform is first impregnated with the carbon-rich precursor solution under sealing conditions, which can be achieved by placing the fiber preform in a mold and then pouring the carbon-rich precursor solution obtained in step S1 into the mold.

[0094] Alternatively, in the above step S2-2, the fiber preform is first impregnated with the silicon-rich precursor solution under sealing conditions, which can be achieved by placing the fiber preform in a mold and then pouring the silicon-rich precursor solution obtained in step S1 into the mold.

[0095] In the present invention, specifically, the pouring is performed under pressurized or vacuum conditions.

[0096] Specifically, the pressurization conditions include: a pressure of 1-3 bar, such as 1 bar, 1.2 bar, 1.25 bar, 1.3 bar, 1.38 bar, 1.4 bar, 1.5 bar, 1.6 bar, 1.8 bar, 2 bar, 2.25 bar, 2.5 bar, 3 bar, and a range consisting of any two of the above values; the vacuum conditions include: a pressure of 0-1 bar, such as 0 bar, 0.2 bar, 0.25 bar, 0.3 bar, 0.38 bar, 0.4 bar, 0.5 bar, 0.6 bar, 0.8 bar, 1 bar, and a range consisting of any two of the above values. Preferably, the pouring is repeated 2-5 times.

[0097] In the present invention, the conditions for the first gel reaction in step S2-1 and the first gel reaction in step S2-2 independently include: a temperature of 40-120° C. and a time of 24-48 hours.

[0098] In the present invention, the temperature may be 40°C, 42°C, 45°C, 50°C, 55°C, 58°C, 56°C, 59°C, 60°C, 62°C, 65°C, 70°C, 78°C, 80°C, 85°C, 90°C, 100°C, 110°C, 115°C, 120°C and a range consisting of any two of the above values, and the time may be 24h, 25h, 28h, 32h, 36h, 37h, 38h, 40h, 42h, 46h, 48h and a range consisting of any two of the above values.

[0099] Furthermore, the inventors discovered that a gradient temperature increase in the first gelation reaction in step S2-1 or step S2-2, i.e., first reacting at 40-80°C for 6-10 hours and then at 80-100°C for 6-10 hours, with a temperature difference of no less than 20°C, can improve the degree of gelation and produce a material with a more complete skeleton structure, thereby simultaneously improving the mechanical properties and ablation resistance of the organosilicon aerogel composite material.

[0100] Furthermore, aging the gel product from the first gelation reaction can further crosslink the gel product, making the molecular arrangement within the gel product more orderly and the network structure more uniform, thereby facilitating the production of an aerogel material with a more complete skeleton. Specifically, the aging conditions include: allowing the gel product to stand at 100-120°C for 6-10 hours.

[0101] In the present invention, preferably, the method further comprises: drying the aged product obtained after the aging. Specifically, the drying method comprises: drying at 20-120° C. for 1-5 days.

[0102] According to a particularly preferred embodiment of the present invention, the drying is performed using a gradient temperature increase. Specifically, the aged product is first dried at 20-30°C for 1-3 days, and then dried at 40-80°C, 80-100°C, and 100-120°C for 12-48 hours, respectively. This prevents severe shrinkage and cracking of the aged product, which would otherwise damage the material's skeleton structure, and ensures the structural integrity of the resulting carbon-rich or silicon-rich composite material.

[0103] Specifically, there is no particular limitation on the location for treating and drying the first gel, and conventional drying methods in the art may be used, such as drying in an oven.

[0104] Specifically, under sealed conditions, the carbon-rich composite material and the silicon-rich precursor solution are subjected to secondary impregnation, which can be achieved by placing the carbon-rich composite material obtained in step S2-1 into a mold, and then pouring the silicon-rich precursor solution obtained in step S1 into the mold.

[0105] Alternatively, under sealed conditions, the silicon-rich composite material is brought into contact with the carbon-rich precursor solution for secondary impregnation, which can be achieved by placing the silicon-rich composite material obtained in step S2-2 into a mold, and then pouring the carbon-rich precursor solution obtained in step S1 into the mold.

[0106] In the present invention, specifically, the pouring is performed under pressurized or vacuum conditions.

[0107] Specifically, the pressurization conditions include: a pressure of 1-3 bar, and the vacuum conditions include: a pressure of 0-1 bar. Preferably, the pouring is repeated 2-5 times.

[0108] In the present invention, specifically, in order to make the second gel reaction more complete, the conditions of the second gel reaction in step S3-1 and the second gel reaction in step S3-2 independently include: temperature of 40-120° C. and time of 24-48 h.

[0109] Furthermore, the inventors found that the second gel reaction in the above-mentioned step S3-1 or the second gel reaction in the above-mentioned step S3-2 is subjected to a gradient temperature increase, that is, first reacting at 40-80°C for 6-10 hours, and then reacting at 80-100°C for 6-10 hours. The temperature difference of the above-mentioned gradient temperature increase is not less than 20°C, for example, it can be 20°C, 21°C, 22°C, 25°C, 28°C, 30°C, 32°C, 38°C, 40°C and a range consisting of any two of the above values, which is beneficial to simultaneously improve the mechanical properties and ablation resistance of the obtained gel product.

[0110] Furthermore, aging the gel product can further improve its stability, making the molecular arrangement within the gel product more orderly and the network structure more uniform, thereby facilitating the production of a wet gel composite material with a more complete skeleton. Specifically, the aging conditions include: allowing the gel product to stand at 100-120°C for 6-10 hours.

[0111] In the present invention, preferably, the method further comprises: drying the obtained aged product (wet gel composite material) after the aging. Specifically, the drying method comprises: drying at 20-120° C. for 1-5 days.

[0112] According to a particularly preferred embodiment of the present invention, the drying is carried out using a gradient temperature increase method. Specifically, the wet gel composite is first dried at 20-30°C for 1-3 days, and then dried at 40-80°C, 80-100°C, and 100-120°C for 12-48 hours, respectively. This prevents severe shrinkage and cracking of the wet gel composite, which would otherwise damage the material's skeleton structure, and ensures the structural integrity of the resulting organosilicon aerogel composite.

[0113] Specifically, there is no particular limitation on the location for treating and drying the second gel, and conventional drying methods in the art may be used, such as drying in an oven.

[0114] In the preparation method of the present invention, a first silane monomer and a polymer monomer with a specific structure are used as raw materials. Due to the cross-linking reaction between the special groups in the first silane monomer (such as the amino group and the thiol group involved in the embodiment of the present invention) and the epoxy group or the isocyanate group in the polymer monomer, a carbon-rich precursor solution is obtained. After the first impregnation with the fiber preform, a carbon-rich composite material with a high degree of cross-linking and excellent mechanical properties is obtained. The silicon-rich precursor solution prepared using the second silane monomer is then impregnated into the carbon-rich composite material for a second time. The silicon-rich precursor solution grows a silicon-rich skeleton in the pores of the carbon-rich composite material, forming a unique interpenetrating double network structure.

[0115] Alternatively, a silicon-rich precursor solution is used to impregnate the fiber preform for the first time to obtain a silicon-rich composite material with excellent ablation resistance, and then a carbon-rich precursor solution is impregnated into the silicon-rich composite material for a second time. The carbon-rich precursor solution grows a carbon-rich skeleton with a high degree of cross-linking and excellent mechanical properties in the pores of the silicon-rich composite material, thereby obtaining an organic silicon aerogel composite material with a unique interpenetrating double network structure.

[0116] Through the first impregnation and the second impregnation, the carbon-rich skeleton in the carbon-rich precursor and the silicon-rich skeleton in the silicon-rich precursor are combined to form a unique interpenetrating double network structure, which can simultaneously construct the mechanical bearing network and thermal defense network of the organosilicon aerogel composite material, thereby significantly improving the mechanical properties of the organosilicon aerogel composite material while effectively ensuring the ablation resistance.

[0117] The preparation method of the present invention is significantly simplified, and does not require solvent exchange or secondary modification. An excellently formed organosilicon aerogel composite material can be obtained only by drying at normal pressure. This overcomes the problems of complex traditional aerogel preparation process, high cost, and inability to balance thermodynamic properties, making organosilicon aerogel composite materials widely used in the field of high-temperature heat insulation.

[0118] The second aspect of the present invention provides an organosilicon aerogel composite material prepared by the method described in the first aspect.

[0119] According to the present invention, specifically, the organosilicon aerogel composite material comprises an organosilicon aerogel matrix and a reinforcement phase. The matrix comprises a carbon-rich skeleton and a silicon-rich skeleton having an interpenetrating network structure, and the reinforcement phase comprises a fiber preform.

[0120] In the present invention, the carbon-rich precursor is obtained by using a first silane monomer and a polymer monomer of a specific structure as raw materials according to the method described in the first aspect of the present invention, performing a first sol reaction, a first gel reaction, aging, and drying. The silicon-rich precursor is obtained by using a second silane monomer of a specific structure according to the method described in the first aspect of the present invention, performing a second sol reaction, a second gel reaction, aging, and drying.

[0121] According to the present invention, specifically, in the organosilicon aerogel matrix, the mass ratio of the carbon-rich skeleton to the silicon-rich skeleton is (1-4):(1-4), for example, it can be 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:4, 1.4:1, 2:1, 2:2.2, 2:2.5, 2:3.5, 3.5:2.5, 3:4 and a range consisting of any two of the above values, preferably (1-2):(1-2), for example, 1:1, 1:1.2, 1:1.4, 1:1.8, 1:2, 1.5:2, 1.75:1.25, 2:1 and a range consisting of any two of the above values.

[0122] In the present invention, the mass ratio of the carbon-rich skeleton to the silicon-rich skeleton satisfies the above range, which can significantly improve the mechanical properties of the organosilicon aerogel composite material while effectively ensuring the ablation resistance.

[0123] According to the present invention, the average pore diameter of the organosilicon aerogel composite material is 130-280 mm, and the porosity is 40-76%.

[0124] In the present invention, when the average pore size of the organosilicon aerogel composite material meets the above range and the porosity meets the above range, the thermodynamic properties and mechanical strength of the organosilicon aerogel composite material can be balanced, so that the organosilicon aerogel composite material has both high ablation resistance and tensile strength.

[0125] According to the present invention, the density of the organosilicon aerogel composite material is 0.51-0.6 g / cm 3 , the tensile strength is not less than 17MPa, the room temperature thermal conductivity is not higher than 0.06W / (m·K), and the mass ablation rate is not higher than 0.52×10 -3 g / s, the linear ablation rate is not higher than 2.64×10 -3 mm / s.

[0126] The third aspect of the present invention provides an application of the organosilicon aerogel composite material described in the second aspect in the field of high-temperature heat insulation.

[0127] The present invention will be described in detail below by way of examples.

[0128] The density of the fiber preform and the organosilicon aerogel composite material were measured in accordance with GB / T 1463-2005;

[0129] Thermogravimetric properties of the silicone aerogel matrix were determined according to GB / T 33047.1-2016 (test temperature: room temperature to 800°C, N2 atmosphere).

[0130] The mass ratio of the carbon-rich skeleton to the silicon-rich skeleton in the organosilicon aerogel matrix is ​​determined by the feed ratio;

[0131] The tensile strength of the silicone aerogel composite material was tested using Type I specimens in GB / T 1447-2005 with a thickness of 10 mm;

[0132] The room temperature thermal conductivity of the organosilicon aerogel composite material was measured according to GB / T 10294-1988;

[0133] The average pore size and porosity of the organosilicon aerogel composite material were determined according to the method of GB / T 21650.1-2008.

[0134] The ablation resistance of the silicone aerogel composite material was determined by oxyacetylene test according to GJB 323B-2018 (experimental temperature was 1000 °C).

[0135] Example 1

[0136] S1. 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether and ethanol were uniformly mixed, and then deionized water was added. The mixture was stirred at room temperature for 30 minutes to promote the hydrolysis of 3-aminopropyltriethoxysilane, and then tetramethylammonium hydroxide (25wt% methanol solution) was added and stirred at room temperature for 5 minutes to obtain a carbon-rich precursor solution; wherein the mass ratio of 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether, ethanol, deionized water and tetramethylammonium hydroxide was 8:16:44.6:1.95:0.34;

[0137] Phenyltriethoxysilane was added to a container, and then ethanol was added to dilute the solution. An appropriate amount of acetic acid was added to adjust the pH value of the solution to 5. Deionized water was then added and stirred at room temperature (25°C) for 30 minutes to promote the hydrolysis of phenyltriethoxysilane. Tetramethylammonium hydroxide (25wt% methanol solution) was then added and stirred at room temperature (25°C) for 5 minutes to uniformly disperse the solution to obtain a silicon-rich precursor solution. The mass ratio of phenyltriethoxysilane, ethanol, acetic acid, deionized water, and tetramethylammonium hydroxide was 16:48:1.28:3.6:0.64.

[0138] S2, the size of the product is 220mm*220mm*10mm and the density is 0.27g / cm 3 The needle-punched structure quartz fiber preform is placed in a mold and sealed, and the carbon-rich precursor solution obtained in S1 is injected into the mold by pressure-assisted and vacuum-assisted methods, wherein the pressure-assisted injection pressure is set to 2 bar and the vacuum-assisted injection pressure is 1 bar, and the process is repeated 3 times. The obtained product and the mold are transferred to a 60°C oven for reaction for 8 hours, and then transferred to an 80°C oven for reaction for 8 hours to obtain a gel product, and the gel product is aged in a 100°C oven for 8 hours, and then the material is taken out of the mold to obtain an aged product, and the aged product is dried at room temperature (25°C) for 24 hours, and then dried independently at 40°C, 80°C, and 100°C for 12 hours to obtain a carbon-rich composite material;

[0139] S3. Place the dried material from step S2 in a 220mm*220mm*10mm mold and seal it. Then, repeat the process of step S2 with the silicon-rich precursor solution prepared in step S1 and pour it into the mold for a second impregnation under the same conditions. Then, transfer the obtained product together with the mold to a 60°C oven for reaction for 8 hours, and then transfer it to an 80°C oven for reaction for 8 hours to obtain a gel product. Aged the gel product in an oven at 100°C for 8 hours, and then remove the material from the mold to obtain a wet gel composite material. Dry the wet gel composite material at room temperature (25°C) for 24 hours, and then dry it independently at each temperature of 40°C, 80°C, and 100°C for 12 hours to obtain a silicone aerogel composite material.

[0140] Figure 2 This is a scanning electron microscope image of an organic aerogel composite material. Figure 2 Obvious carbon-rich skeleton and silicon-rich skeleton structures can be seen, and the carbon-rich skeleton and silicon-rich skeleton form an interpenetrating double network structure.

[0141] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0142] Example 2

[0143] The method of Example 1 was followed, except that the mass ratio of 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether, ethanol, deionized water and tetramethylammonium hydroxide was 8:16:36:1.95:0.3, and the mass ratio of phenyltriethoxysilane, ethanol, acetic acid, deionized water and tetramethylammonium hydroxide was 16:64:1.6:3.6:0.8.

[0144] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0145] Example 3

[0146] The method of Example 1 was followed, except that the mass ratio of 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether, ethanol, deionized water and tetramethylammonium hydroxide was 8:16:96:1.95:0.6, and the mass ratio of phenyltriethoxysilane, ethanol, acetic acid, deionized water and tetramethylammonium hydroxide was 16:24:0.8:3.6:0.4.

[0147] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0148] Example 4

[0149] The method of Example 1 was followed, except that 3-aminopropyltriethoxysilane was replaced with 3-aminopropylmethyldiethoxysilane. Accordingly, the mass ratio of 3-aminopropylmethyldiethoxysilane, resorcinol diglycidyl ether, ethanol, deionized water, and tetramethylammonium hydroxide was 8:16:44.6:1.51:0.34.

[0150] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0151] Example 5

[0152] The method of Example 1 was followed, except that 3-aminopropyltriethoxysilane was replaced with 3-mercaptopropyltriethoxysilane. Accordingly, the mass ratio of 3-mercaptopropyltriethoxysilane resorcinol diglycidyl ether, ethanol, deionized water and tetramethylammonium hydroxide was 8:16:44.6:1.81:0.34.

[0153] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0154] Example 6

[0155] The method of Example 1 is followed, except that resorcinol diglycidyl ether is replaced with toluene diisocyanate. Accordingly, the mass ratio of 3-aminopropylmethyldiethoxysilane, toluene diisocyanate, ethanol, deionized water and tetramethylammonium hydroxide is 8:16:44.6:1.51:0.34.

[0156] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0157] Example 7

[0158] The method of Example 1 was followed, except that phenyltriethoxysilane was replaced with tetraethoxysilane. Accordingly, the mass ratio of tetraethoxysilane, ethanol, acetic acid, deionized water, and tetramethylammonium hydroxide was 16:48:1.28:5.54:0.64.

[0159] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0160] Example 8

[0161] The method of Example 1 is followed, except that the density of the fiber preform is changed to 0.2 g / cm 3 .

[0162] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0163] Example 9

[0164] The method of Example 1 is followed, except that the density of the fiber preform is changed to 0.3 g / cm 3 .

[0165] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0166] Example 10

[0167] The method of Example 1 was followed, except that the mass ratio of 3-aminopropyltriethoxysilane to resorcinol diglycidyl ether was 1:1, and correspondingly, the mass ratio of 3-aminopropyltriethoxysilane to resorcinol diglycidyl ether ethanol, deionized water, and tetramethylammonium hydroxide was 8:8:29.7:1.95:0.23.

[0168] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0169] Example 11

[0170] The method of Example 1 was followed, except that the mass ratio of 3-aminopropyltriethoxysilane to resorcinol diglycidyl ether was 2:1, and correspondingly, the mass ratio of 3-aminopropyltriethoxysilane to resorcinol diglycidyl ether ethanol, deionized water, and tetramethylammonium hydroxide was 16:8:44.6:3.91:0.34.

[0171] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0172] Example 12

[0173] The method of Example 1 is followed, except that when preparing the silicon-rich precursor solution, the raw materials are phenyltriethoxysilane, tetraethoxysilane, ethanol, acetic acid, deionized water and tetramethylammonium hydroxide, and their ratios are 8:16:72:1.92:7.34:0.96.

[0174] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0175] Example 13

[0176] The method of Example 1 is followed, except that when preparing the silicon-rich precursor solution, the raw materials are phenyltriethoxysilane, tetraethoxysilane, ethanol, acetic acid, deionized water and tetramethylammonium hydroxide, and their ratios are 16:8:72:1.92:6.37:0.96.

[0177] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0178] Example 14

[0179] The method of Example 1 is followed, except that the mass ratio of 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether, ethanol, deionized water and tetramethylammonium hydroxide is 8:32:74.3:1.95:0.57.

[0180] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0181] Example 15

[0182] The method of Example 1 was followed, except that the mass ratio of 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether, ethanol, deionized water, and tetramethylammonium hydroxide was 8:16:216:1.95:1.2, and the mass ratio of phenyltriethoxysilane, ethanol, acetic acid, deionized water, and tetramethylammonium hydroxide was 16:16:0.64:3.6:0.32.

[0183] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0184] Example 16

[0185] S1. Phenyltriethoxysilane is added to a container, and then ethanol is added to dilute the solution. An appropriate amount of acetic acid is added to adjust the pH value of the solution to 5. Deionized water is then added and stirred at room temperature (25°C) for 30 minutes to promote the hydrolysis of phenyltriethoxysilane. Tetramethylammonium hydroxide (25wt% methanol solution) is then added and stirred at room temperature (25°C) for 5 minutes to uniformly disperse the solution to obtain a silicon-rich precursor solution. The mass ratio of phenyltriethoxysilane, ethanol, acetic acid, deionized water, and tetramethylammonium hydroxide is 16:48:1.28:3.6:0.64.

[0186] 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether and ethanol were uniformly mixed, and then deionized water was added, and the mixture was stirred at room temperature for 30 minutes to promote the hydrolysis of 3-aminopropyltriethoxysilane. Then, tetramethylammonium hydroxide (25wt% methanol solution) was added and stirred at room temperature for 5 minutes to obtain a carbon-rich precursor solution; wherein the mass ratio of 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether, ethanol, deionized water and tetramethylammonium hydroxide was 8:16:44.6:1.95:0.34;

[0187] S2, the size of the product is 220mm*220mm*10mm and the density is 0.27g / cm 3The needle-punched structure quartz fiber preform is placed in a mold and sealed, and the silicon-rich precursor solution obtained in S1 is injected into the mold by pressure-assisted and vacuum-assisted methods, wherein the pressure-assisted injection pressure is set to 2 bar and the vacuum-assisted injection pressure is 1 bar, and the process is repeated 3 times. The obtained product and the mold are transferred to a 60°C oven for reaction for 8 hours, and then transferred to an 80°C oven for reaction for 8 hours to obtain a gel product, and the gel product is aged in a 100°C oven for 8 hours, and then the material is taken out of the mold to obtain an aged product, and the aged product is dried at room temperature (25°C) for 24 hours, and then dried independently at 40°C, 80°C, and 100°C for 12 hours to obtain a silicon-rich composite material;

[0188] S3. Place the dried material from step S2 in a 220mm*220mm*10mm mold and seal it. Then, repeat the process of step S2 with the carbon-rich precursor solution prepared in step S1 and pour it into the mold for a second impregnation under the same conditions. Then, transfer the obtained product together with the mold to a 60°C oven for reaction for 8 hours, and then transfer it to an 80°C oven for reaction for 8 hours to obtain a gel product. Aged the gel product in an oven at 100°C for 8 hours, and then remove the material from the mold to obtain a wet gel composite material. Dry the wet gel composite material at room temperature (25°C) for 24 hours, and then dry it independently at 40°C, 80°C, and 100°C for 12 hours to obtain a silicone aerogel composite material.

[0189] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0190] Comparative Example 1

[0191] S1. 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether and ethanol were uniformly mixed, and then deionized water was added. The mixture was stirred at room temperature for 30 minutes to promote the hydrolysis of 3-aminopropyltriethoxysilane, and then tetramethylammonium hydroxide (25wt% methanol solution) was added and stirred at room temperature for 5 minutes to obtain a carbon-rich precursor solution; wherein the mass ratio of 3-aminopropyltriethoxysilane, resorcinol diglycidyl ether, ethanol, deionized water and tetramethylammonium hydroxide was 8:16:16:1.95:0.2;

[0192] S2, the size of the product is 220mm*220mm*10mm and the density is 0.27g / cm 3The needle-punched structure quartz fiber preform is placed in a mold and sealed, and the carbon-rich precursor solution obtained in S1 is injected into the mold by pressure-assisted and vacuum-assisted methods, wherein the pressure-assisted injection pressure is set to 2 bar, and the vacuum-assisted injection pressure is 1 bar, and the process is repeated 3 times. The obtained product is transferred together with the mold to a 60°C oven for reaction for 8 hours, and then transferred to an 80°C oven for reaction for 8 hours to obtain a gel product. The gel product is aged in an oven at 100°C for 8 hours, and then the material is taken out of the mold to obtain an aged product. The aged product is dried at room temperature (25°C) for 24 hours, and then dried independently at 40°C, 80°C, and 100°C for 12 hours to obtain a carbon-rich composite material.

[0193] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0194] Comparative Example 2

[0195] S1. Phenyltriethoxysilane was added to a container, followed by ethanol to dilute the solution. An appropriate amount of acetic acid was added to adjust the pH of the solution to 5. Deionized water was then added and stirred at room temperature (25°C) for 30 minutes to promote the hydrolysis of the phenyltriethoxysilane. Tetramethylammonium hydroxide (25 wt% methanol solution) was then added and stirred at room temperature (25°C) for 5 minutes to uniformly disperse the solution to obtain a silicon-rich precursor solution. The mass ratio of phenyltriethoxysilane, ethanol, acetic acid, deionized water, and tetramethylammonium hydroxide was 16:10.67:0.53:3.6:0.27.

[0196] S2, the size of the product is 220mm*220mm*10mm and the density is 0.27g / cm 3 The needle-punched structure quartz fiber preform is placed in a mold and sealed, and the silicon-rich precursor solution obtained in S1 is injected into the mold by pressure-assisted and vacuum-assisted methods, wherein the pressure-assisted injection pressure is set to 2 bar and the vacuum-assisted injection pressure is 1 bar, and the process is repeated 3 times. The obtained product and the mold are transferred to a 60°C oven for reaction for 8 hours, and then transferred to an 80°C oven for reaction for 8 hours to obtain a gel product, and the gel product is aged in a 100°C oven for 8 hours, and then the material is taken out of the mold to obtain an aged product, and the aged product is dried at room temperature (25°C) for 24 hours, and then dried independently at 40°C, 80°C, and 100°C for 12 hours to obtain a silicon-rich composite material;

[0197] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0198] Comparative Example 3

[0199] S1. 3-aminopropyltriethoxysilane and ethanol were uniformly mixed, and then deionized water was added. The mixture was stirred at room temperature for 30 minutes to promote the hydrolysis of 3-aminopropyltriethoxysilane. Then, tetramethylammonium hydroxide (25 wt% methanol solution) was added and stirred at room temperature for 5 minutes to obtain a carbon-rich precursor solution; wherein the mass ratio of 3-aminopropyltriethoxysilane, ethanol, deionized water and tetramethylammonium hydroxide was 24:44.6:5.85:0.34;

[0200] Phenyltriethoxysilane was added to a container, and then ethanol was added to dilute the solution. An appropriate amount of acetic acid was added to adjust the pH value of the solution to 5. Deionized water was then added and stirred at room temperature (25°C) for 30 minutes to promote the hydrolysis of phenyltriethoxysilane. Tetramethylammonium hydroxide (25wt% methanol solution) was then added and stirred at room temperature (25°C) for 5 minutes to uniformly disperse the solution to obtain a silicon-rich precursor solution. The mass ratio of phenyltriethoxysilane, ethanol, acetic acid, deionized water, and tetramethylammonium hydroxide was 16:48:1.28:3.6:0.64.

[0201] S2, the size of the product is 220mm*220mm*10mm and the density is 0.27g / cm 3 The needle-punched structure quartz fiber preform is placed in a mold and sealed, and the carbon-rich precursor solution obtained in S1 is injected into the mold by pressure-assisted and vacuum-assisted methods, wherein the pressure-assisted injection pressure is set to 2 bar and the vacuum-assisted injection pressure is 1 bar, and the process is repeated 3 times. The obtained product and the mold are transferred to a 60°C oven for reaction for 8 hours, and then transferred to an 80°C oven for reaction for 8 hours to obtain a gel product, and the gel product is aged in a 100°C oven for 8 hours, and then the material is taken out of the mold to obtain an aged product, and the aged product is dried at room temperature (25°C) for 24 hours, and then dried independently at 40°C, 80°C, and 100°C for 12 hours to obtain a carbon-rich composite material;

[0202] S3. Place the dried material from step S2 in a 220mm*220mm*10mm mold and seal it. Then, repeat the process of step S2 with the silicon-rich precursor solution prepared in step S1 and pour it into the mold for a second impregnation under the same conditions. Then, transfer the obtained product together with the mold to a 60°C oven for reaction for 8 hours, and then transfer it to an 80°C oven for reaction for 8 hours to obtain a gel product. Aged the gel product in an oven at 100°C for 8 hours, and then remove the material from the mold to obtain a wet gel composite material. Dry the wet gel composite material at room temperature (25°C) for 24 hours, and then dry it independently at each temperature of 40°C, 80°C, and 100°C for 12 hours to obtain a silicone aerogel composite material.

[0203] The average pore size, porosity, density, room temperature thermal conductivity of the composite material, and the mass ratio M1 of the carbon-rich skeleton to the silicon-rich skeleton in the silicone aerogel matrix are shown in Table 1. The mass ablation rate, linear ablation rate, and tensile strength test results are shown in Table 2.

[0204] Table 1

[0205]

[0206] Note: M1 refers to the mass ratio of carbon-rich skeleton to silicon-rich skeleton in the silicone aerogel matrix.

[0207] Table 2

[0208]

[0209] The organosilicon aerogel composite materials prepared in Example 1, Example 2 and Example 3 were subjected to tensile testing using an electronic universal testing machine according to the method of GB / T 1447-2005 to obtain Figure 3 As shown in the curve graph, it can be seen from the figure that the tensile strength of the organosilicon aerogel composite material prepared in Example 2 is the highest, 48.2 MPa.

[0210] The thermal stability of the organosilicon aerogel matrix in the organosilicon aerogel composite materials of Examples 1, 2 and 3 under N2 was evaluated using a thermogravimetric analyzer (test temperature ranged from room temperature to 800°C, N2 atmosphere). Figure 4 As shown in the curve chart, in the organosilicon aerogel composite material prepared in Example 3, the residual mass of the organosilicon aerogel matrix is ​​66.3 wt %, and the loss mass is 33.7 wt %.

[0211] Examples 1-3 demonstrate that the mechanical properties of the composite material improve with increasing solute mass fraction in the first mixed solution, while the thermodynamic properties of the material improve with increasing solute mass fraction in the second mixed solution. The organosilicon aerogel composite material produced according to the preparation method of the present invention can simultaneously exhibit high mechanical properties and ablation resistance. However, Example 3, which does not meet the preferred embodiment, has lower mechanical properties than Examples 1 and 2 due to the solute mass fraction in the first mixed solution being only 20%. In Example 2, the solute mass fraction in the second mixed solution being only 20%, resulting in slightly poorer thermodynamic properties.

[0212] The embodiments that meet the preferred embodiments of the present invention achieve further effects, specifically, the tensile strength is not less than 30 MPa, the room temperature thermal conductivity is not higher than 0.06 W / (m·K), the mass ablation rate is not higher than 0.5×10 -3 g / s, the linear ablation rate is not higher than 2×10 -3 mm / s.

[0213] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing an organosilicon aerogel composite material, characterized in that: The following steps are involved: S1, mixing a first silane monomer, a polymer monomer, and an alcohol solvent to obtain a first mixed solution, and performing a first sol reaction to obtain a carbon-rich precursor solution; Mixing a second silane monomer with an alcohol solvent to obtain a second mixed solution, and performing a second sol reaction to obtain a silicon-rich precursor solution; S2-1. Under sealed conditions, the fiber preform is initially impregnated with the carbon-rich precursor solution, followed by a first gelation reaction to obtain a carbon-rich composite material. Alternatively, S2-2. Under sealed conditions, the fiber preform is initially impregnated with the silicon-rich precursor solution, followed by a first gelation reaction to obtain a silicon-rich composite material. S3-1, under sealed conditions, contacting the carbon-rich composite material with the silicon-rich precursor solution for secondary impregnation, and then undergoing a second gelation reaction; or, S3-2, under sealed conditions, contacting the silicon-rich composite material with the carbon-rich precursor solution for secondary impregnation, and then undergoing a second gelation reaction; An organosilicon aerogel composite material is obtained; wherein the first silane monomer has a structure shown in Formula A: n is an integer between 2 and 6, R A1 is selected from amino or thiol, R A2 is selected from C1-C4 alkyl or C1-C4 alkoxy, R A3 and R A4 Each independently selected from C1-C4 alkoxy; The second silane monomer has a structure shown in Formula B: R B1 is selected from C2-C4 alkenyl, aryl or C1-C4 alkoxy, R B2 、R B3 and R B4 Each is independently selected from C1-C4 alkoxy.

2. The method according to claim 1, characterized in that The first silane monomer is selected from 3-aminopropyl alkoxysilane and / or 3-mercaptopropyl alkoxysilane; and / or, the polymer monomer is selected from glycidyl ether and / or isocyanate; And / or, the second silane monomer is at least one selected from vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, tetramethoxysilane and tetraethoxysilane.

3. The method according to claim 1 or 2, characterized in that The fiber preform is woven from organic fibers and / or inorganic fibers; And / or, the density of the fiber preform is 0.1-0.5 g / cm 3 .

4. The method according to claim 1 or 2, characterized in that In step S1, in the first mixed solution, the mass ratio of the first silane monomer to the polymer monomer is (1-4):(1-4); and / or, in the first mixed solution, the sum of the mass of the first silane monomer and the polymer monomer accounts for 20-60% of the total mass of the first mixed solution; And / or, the mass of the second silane monomer in the second mixed solution accounts for 20-60% of the total mass of the second mixed solution.

5. The method according to claim 1 or 2, characterized in that The first sol reaction step comprises: adding deionized water to the first mixed solution at room temperature, stirring for 30-60 minutes, then adding an alkaline catalyst and continuing to stir for 5-15 minutes to obtain a carbon-rich precursor solution; And / or, at room temperature, the second sol reaction step includes: adding an acidic catalyst dropwise to the second mixed solution, stirring and mixing uniformly, then adding deionized water, stirring for 30-60 minutes, and then adding a basic catalyst and continuing to stir for 5-15 minutes to obtain a silicon-rich precursor solution.

6. The method according to claim 1 or 2, characterized in that The first impregnation and the second impregnation are each independently performed under pressurized or vacuum conditions; And / or, the pressurized condition includes: a pressure of 1-3 bar, and the vacuum condition includes: a pressure of 0-1 bar; And / or, the conditions of the first gel reaction and the second gel reaction independently include: a reaction temperature of 40-120° C., and a reaction time of 24-48 hours.

7. The method according to claim 1 or 2, characterized in that The method further comprises: performing a first aging and a first drying on the gel product obtained after the first gel reaction; performing a second aging and a second drying on the gel product obtained after the second gel reaction; And / or, the first aging and second aging conditions each independently include: standing the gel product at 100-120° C. for 6-10 h; And / or, the conditions for the first drying and the second drying each independently include: drying at 20-120° C. for 1-5 days.

8. An organosilicon aerogel composite material prepared by the preparation method according to any one of claims 1 to 7.

9. The organosilicon aerogel composite material according to claim 8, characterized in that: The organosilicon aerogel composite material comprises an organosilicon aerogel matrix and a reinforcement phase, wherein the matrix comprises a carbon-rich skeleton and a silicon-rich skeleton having an interpenetrating network structure, and the reinforcement phase comprises a fiber preform; In the organosilicon aerogel matrix, the mass ratio of the carbon-rich skeleton to the silicon-rich skeleton is (1-4):(1-4); The average pore size of the organosilicon aerogel composite material is 130-280 mm, the porosity is 40-76%, and the density is 0.51-0.6 g / cm 3 .

10. Use of the organosilicon aerogel composite material according to claim 8 or 9 in the field of high-temperature heat insulation.

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