Aerogel building block and preparation method thereof

Abstract

The invention discloses an aerogel building block and a preparation method thereof. Comprising the following steps: step 1, stirring and mixing cement, silica fume, gravel and fine sand, adding water, modified silicon dioxide aerogel and a water reducing agent, and stirring and mixing to obtain slurry; 2, after the slurry is subjected to pouring forming, standing is conducted for 1-2 h, demolding and cutting are conducted, steam curing is conducted for 6-8 days at the temperature of 60-80 DEG C, standing is conducted for 18-20 days at the temperature of 20-25 DEG C, and the aerogel building block is obtained. The preparation method has the beneficial effects that the modified silicon dioxide aerogel is enhanced and combined with a cement matrix, so that the dispersity and the structural stability are improved, meanwhile, the block is endowed with excellent heat insulation, flame retardance and mechanical properties, and the problems that a traditional aerogel block is easy to damage and single in function are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building material preparation, and particularly relates to an aerogel block and a preparation method thereof. BACKGROUND

[0002] Traditional building block materials such as ordinary concrete and aerated concrete are widely used in the field of building, but their thermal conductivity is relatively high, and their heat insulation performance is insufficient, which cannot meet the needs of modern building energy saving and environmental protection.

[0003] In recent years, aerogel is considered as an ideal heat insulation material due to its ultra-low thermal conductivity and light and porous characteristics, but there are still many problems in practical application. First, the compatibility of ordinary aerogel with cement-based materials is poor, and it is easy to agglomerate during mixing, which leads to uneven dispersion and affects the overall performance of the block. Secondly, the brittleness of aerogel is high, and it is easy to be damaged in the process of block forming, cutting and subsequent processing, which loses its porous characteristics and reduces the heat insulation effect. In addition, the mechanical strength of the existing aerogel block is often insufficient, which cannot balance the heat insulation performance and structural stability, limiting its application in load-bearing structures. Although there are some modified aerogel products on the market, their preparation process is complex, the cost is high, and the function is single, which cannot meet the additional needs of flame retardation, chemical corrosion resistance and the like.

[0004] Therefore, in order to solve the above problems, the application provides an aerogel block and a preparation method thereof. SUMMARY

[0005] The application aims to overcome the defects of the prior art and provide an aerogel block and a preparation method thereof.

[0006] The object of the application can be achieved by the following technical solutions. A preparation method of an aerogel block, comprising the following steps: Step 1: after mixing cement, silica fume, gravel and fine sand, water, modified silica aerogel and water reducing agent are added and mixed to obtain a slurry; Step 2: after the slurry is poured and formed, it is demolded after 1-2h of static curing, and after cutting, it is steamed for 6-8 days at 60-80 DEG C, and then it is placed for 18-20 days at 20-25 DEG C to obtain the aerogel block.

[0007] More preferably, the preparation raw materials of the slurry include the following components: 80-100 parts of cement, 20-30 parts of silica fume, 100-120 parts of gravel, 80-100 parts of fine sand, 30-50 parts of water, 18-20 parts of modified silica aerogel and 1-2 parts of water reducing agent.

[0008] More preferably, the preparation process of the modified silica aerogel is: A1: Mix water glass with deionized water, stir until uniform, then drop into strong acid styrene cation exchange resin, collect the solution, and adjust the pH to 5 using ammonia water, stir for 1-2 min, then pour into a mold, after converting to a gel, age at room temperature for 24 h, and replace with anhydrous ethanol twice, to obtain a silica wet gel; A2: Add the silica wet gel obtained in step A1 to a 3-methacryloyloxypropyltrimethoxysilane solution, soak for 24 h, then react at 50-60℃ for 3-4 h, after the reaction is complete, wash to obtain an alkenylated silica wet gel; A3: Add the modified monomer, 2-acrylamide-2-methyl-1-propanesulfonic acid, and maleic anhydride to N,N-dimethylformamide and stir until uniform, then add the alkenylated silica wet gel, stand for 24 h, then move into an azobisisobutyronitrile solution, soak for 1-2 h, then react at 70-80℃ for 3-4 h, after the reaction is complete, wash and dry to obtain a modified silica aerogel.

[0009] In the scheme, water glass is used as the silicon source, sodium ions are removed by cation exchange resin to generate a silicic acid solution, then under the catalysis of ammonia water, the silicic acid molecules undergo condensation reaction to form a three-dimensional network structure silica wet gel. Subsequently, 3-methacryloyloxypropyltrimethoxysilane undergoes condensation reaction with the hydroxyl groups on the surface of the silica wet gel to form covalent bonds, introducing double bonds to the surface of the gel. Finally, the solution of various double bond monomers penetrates into the pores of the gel, and under the action of the initiator azobisisobutyronitrile (AIBN), free radical polymerization reaction occurs, and the monomers are covalently connected to the surface of the silica skeleton.

[0010] More preferably, in step A1, the volume ratio of water glass to deionized water is 1:3.

[0011] More preferably, in step A2, the concentration of the 3-methacryloyloxypropyltrimethoxysilane solution is 37.5 vol%.

[0012] More preferably, the raw materials for preparing the modified silica aerogel include the following components: by weight fraction, 3-4 parts of modified monomer, 25-6 parts of 2-acrylamide-2-methyl-1-propanesulfonic acid, 2-3 parts of maleic anhydride, 80-100 parts of N,N-dimethylformamide, 60-70 parts of alkenylated silica wet gel, and 1-2 parts of azobisisobutyronitrile solution; the concentration of the azobisisobutyronitrile solution is 4-5 wt%.

[0013] More preferably, the preparation process of the modified monomer is as follows: S1: 2-amino-1,3,4-thiadiazole is mixed with ethanol, the temperature is raised to 50℃, stirring for 10-15 min, then p-hydroxybenzaldehyde is added, the temperature is raised to 90℃, reflux stirring for 8-10 h, then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is added, keeping 90℃, continue to react for 10-12 h, after the reaction is completed, cool to room temperature, post-processing, to obtain intermediate A; S2: intermediate A, sodium hydroxide and water are mixed, stirring for 3-5 min, to obtain a mixed solution; then acryloyl chloride is dissolved in acetonitrile, added to the mixed solution, reaction at room temperature for 5-6 h, filtration, washing, drying, to obtain a modified monomer.

[0014] More preferably, the preparation raw materials of the intermediate A include the following components: 8-10 parts of amino-1,3,4-thiadiazole, 80-100 parts of ethanol, 12-15 parts of p-hydroxybenzaldehyde, 20-22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, by weight.

[0015] More preferably, the preparation raw materials of the modified monomer include the following components: 10-12 parts of intermediate A, 0.5-1 parts of sodium hydroxide, 20-30 parts of water, 1-2 parts of acryloyl chloride, 20-30 parts of acetonitrile, by weight.

[0016] In the scheme, the amino group of 2-amino-1,3,4-thiadiazole and the aldehyde group of p-hydroxybenzaldehyde first undergo condensation reaction to generate imine (Schiff base) by dehydration, and refluxing at 90℃ promotes the reaction to be complete; then the C=N double bond of the imine and the P-H bond of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) add to form the intermediate A containing phosphorus heterocycle, the phenolic hydroxyl group is reserved, then the phenolic hydroxyl group generates phenolic oxygen anion under the action of sodium hydroxide, and esterification reaction occurs with acryloyl chloride in acetonitrile to form the modified monomer containing carbon-carbon double bond, and the specific synthesis is as shown below: The beneficial effects of the present application are: Firstly, in the scheme, after the modified silica aerogel is treated by alkenylation (step A2), carbon-carbon double bonds are introduced on the surface, which can be connected with the modified monomer, 2-acrylamide-2-methyl-1-propanesulfonic acid, maleic anhydride and the like added subsequently through free radical polymerization reaction (step A3) to form covalent bonds, so that the surface of the aerogel is grafted with polymer chains having polar groups (such as sulfonic acid group and acyl group). These polar groups can produce stronger interaction with hydroxyl groups and the like in inorganic matrix materials such as cement and silica fume, improve the dispersibility of the aerogel in the slurry, avoid agglomeration, and thus ensure that the functional properties of the aerogel are uniformly exerted in the building blocks.

[0017] Secondly, the silica wet gel is replaced by anhydrous ethanol (step A1) and modified by alkenylation, so that the skeleton structure is more stable; and the polymer chains introduced by covalent bonds further form "support" and "wrap" to the silica skeleton, reduce the structure damage of the aerogel in the preparation process such as cutting and steam curing, maintain the integrity of the three-dimensional porous network structure, and ensure the performance (such as low thermal conductivity) of the aerogel.

[0018] Thirdly, phosphorus heterocyclic groups (from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and thiadiazole groups (from 2-amino-1,3,4-thiadiazole) are introduced in the preparation process of the modified monomer, which are combined into the aerogel structure through polymerization, and can endow the aerogel with excellent flame retardant performance and chemical stability; at the same time, the sulfonic acid group in 2-acrylamide-2-methyl-1-propanesulfonic acid has strong hydrophilicity, which can enhance the interfacial bonding between the aerogel and the cement hydration product, and further improve the overall mechanical properties of the block. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] Embodiment one: a preparation method of an aerogel block, comprising the following steps: Step 1: after mixing 80 parts of cement, 20 parts of silica fume, 100 parts of crushed stone and 80 parts of fine sand, 30 parts of water, 18 parts of modified silica aerogel and 1 part of water reducing agent (model KT-01, purchased from Jilin Tuxin Chemical Technology Co., Ltd.) are added and mixed, to obtain a slurry; Step 2: after the slurry is cast and shaped, it is demolded after 1h of static curing, and after cutting, it is steam cured at 60℃ for 6 days, and then it is statically cured at 20℃ for 18 days, to obtain the aerogel block; The preparation process of the modified silica aerogel is as follows: A1: after mixing water glass and deionized water (the volume ratio of water glass to deionized water is 1:3), stirring uniformly, dropping into strong acid styrene cation exchange resin, collecting the solution, adjusting the pH to 5 using ammonia water, stirring for 1 min, and then pouring into a mold, aging at room temperature for 24 h after converting into a gel, and replacing twice with anhydrous ethanol, to obtain a silica wet gel; A2: The silica wet gel obtained in step A1 is added to a 3-methacryloxypropyltrimethoxysilane solution (the concentration of the 3-methacryloxypropyltrimethoxysilane solution is 37.5 vol%) and soaked for 24 h, followed by reaction at 50℃ for 3 h. After the reaction is completed, washing is performed to obtain an alkenylated silica wet gel; A3: 3 parts of a modified monomer, 25 parts of acrylamide-2-methyl-1-propanesulfonic acid, and 2 parts of maleic anhydride are added to 80 parts of N,N-dimethylformamide and stirred uniformly, followed by addition of 60 parts of the alkenylated silica wet gel, standing for 24 h, and then being transferred into 1 part of an azobisisobutyronitrile solution (the concentration of the azobisisobutyronitrile solution is 4 wt%) and soaked for 1 h. After that, reaction is performed at 70℃ for 3 h. After the reaction is completed, washing and drying are performed to obtain a modified silica aerogel; The preparation process of the modified monomer is as follows: S1: 8 parts of 2-amino-1,3,4-thiadiazole are mixed with 80 parts of ethanol, the temperature is raised to 50℃, and stirring is performed for 10 min. Then, 12 parts of p-hydroxybenzaldehyde are added, the temperature is raised to 90℃, and reflux stirring is performed for 8 h. Next, 20 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are added, and the reaction is continued at 90℃ for 10 h. After the reaction is completed, the solution is cooled to room temperature, and post-processing is performed to obtain an intermediate A; S2: 10 parts of the intermediate A, 0.5 parts of sodium hydroxide, and 20 parts of water are mixed to obtain a mixed solution. Then, 1 part of acryloyl chloride is dissolved in 20 parts of acetonitrile and added to the mixed solution. The reaction is performed at room temperature for 5 h, followed by filtration, washing, and drying to obtain a modified monomer.

[0021] Example 2: A preparation method of an aerogel block, comprising the following steps: Step 1: 100 parts of cement, 30 parts of silica fume, 120 parts of crushed stone, and 100 parts of fine sand are mixed and stirred, and then 50 parts of water, 20 parts of the modified silica aerogel, and 2 parts of a water reducing agent (model KT-01, purchased from Jilin Tuxin Chemical Technology Co., Ltd.) are added and stirred to obtain a slurry; Step 2: After the slurry is cast and shaped, it is demolded after standing for 2 h, and then cut. After steaming at 80℃ for 8 days and standing at 25℃ for 20 days, an aerogel block is obtained; The preparation process of the modified silica aerogel is as follows: A1: Water glass and deionized water are mixed (the volume ratio of the water glass to the deionized water is 1:3), stirred uniformly, and then added dropwise into a strong-acid styrene cation exchange resin. The solution is collected, and the pH is adjusted to 5 using ammonia water. After stirring for 2 min, the solution is poured into a mold. After being converted into a gel, the solution is aged at room temperature for 24 h and replaced with anhydrous ethanol twice to obtain a silica wet gel; A2: The silica wet gel obtained in step A1 is added to a 3-methacryloxypropyltrimethoxysilane solution (the concentration of the 3-methacryloxypropyltrimethoxysilane solution is 37.5 vol%) and soaked for 24 h, followed by reaction at 60°C for 4 h. After the reaction is completed, washing is performed to obtain an alkenylated silica wet gel; A3: 4 parts of a modified monomer, 26 parts of acrylamide-2-methyl-1-propanesulfonic acid, and 3 parts of maleic anhydride are stirred uniformly in 100 parts of N,N-dimethylformamide, followed by the addition of 70 parts of the alkenylated silica wet gel. After standing for 24 h, 2 parts of an azobisisobutyronitrile solution (the concentration of the azobisisobutyronitrile solution is 5 wt%) is added, and soaking is performed for 2 h. After reaction at 80°C for 4 h, the reaction is completed, washing is performed, and drying is performed to obtain a modified silica aerogel; The preparation process of the modified monomer is as follows: S1: 10 parts of 2-amino-1,3,4-thiadiazole are mixed with 100 parts of ethanol, the temperature is raised to 50°C, and stirring is performed for 15 min. Then, 15 parts of p-hydroxybenzaldehyde are added, the temperature is raised to 90°C, and reflux stirring is performed for 10 h. Next, 22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are added, and reaction is continued at 90°C for 12 h. After the reaction is completed, the temperature is cooled to room temperature, and post-processing is performed to obtain an intermediate A; S2: 12 parts of the intermediate A, 1 part of sodium hydroxide, and 30 parts of water are mixed to obtain a mixed solution. Then, 2 parts of acryloyl chloride are dissolved in 30 parts of acetonitrile and added to the mixed solution. Reaction is performed at room temperature for 6 h, and then filtering, washing, and drying are performed to obtain a modified monomer.

[0022] Example Three: A preparation method of an aerogel block, including the following steps: Step 1: After 90 parts of cement, 25 parts of silica fume, 110 parts of crushed stone, and 90 parts of fine sand are stirred and mixed, 40 parts of water, 19 parts of a modified silica aerogel, and 1.5 parts of a water reducing agent (model KT-01, purchased from Jilin Tuxin Chemical Technology Co., Ltd.) are added and stirred and mixed to obtain a slurry; Step 2: After the slurry is cast and formed, it is demolded after standing for 1.5 h, and then cut. After steam curing at 70°C for 7 days, the aerogel block is obtained after standing at 22.5°C for 19 days; The preparation process of the modified silica aerogel is as follows: A1: After water glass and deionized water are mixed (the volume ratio of the water glass to the deionized water is 1:3) and stirred uniformly, the solution is collected by dripping into a strong-acid styrene cation exchange resin. Ammonia water is used to adjust the pH to 5, and the solution is stirred for 1.5 min and then poured into a mold. After being converted into a gel, the silica wet gel is aged at room temperature for 24 h and replaced with anhydrous ethanol twice. A2: The silica wet gel obtained in step A1 is added to a 3-methacryloxypropyltrimethoxysilane solution (the concentration of the 3-methacryloxypropyltrimethoxysilane solution is 37.5 vol %), soaked for 24 h, and then reacted at 55°C for 3.5 h. After the reaction is completed, washing is performed to obtain an alkenylated silica wet gel; A3: 3.5 parts of a modified monomer, 25.5 parts of acrylamide-2-methyl-1-propanesulfonic acid, and 2.5 parts of maleic anhydride are stirred uniformly in 90 parts of N,N-dimethylformamide, and then 65 parts of the alkenylated silica wet gel is added. After standing for 24 h, 1.5 parts of an azobisisobutyronitrile solution (the concentration of the azobisisobutyronitrile solution is 4.5 wt %) is added, soaked for 1.5 h, and then reacted at 75°C for 3.5 h. After the reaction is completed, washing and drying are performed to obtain a modified silica aerogel; The preparation process of the modified monomer is as follows: S1: 9 parts of 2-amino-1,3,4-thiadiazole is mixed with 90 parts of ethanol, the temperature is raised to 50°C, and stirring is performed for 12.5 min. Then, 13.5 parts of p-hydroxybenzaldehyde is added, the temperature is raised to 90°C, and reflux stirring is performed for 9 h. Next, 21 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is added, and the reaction is continued at 90°C for 11 h. After the reaction is completed, the temperature is cooled to room temperature, and post-processing is performed to obtain intermediate A; S2: 11 parts of intermediate A, 0.75 parts of sodium hydroxide, and 25 parts of water are mixed to obtain a mixed solution. Then, 1.5 parts of acryloyl chloride is dissolved in 25 parts of acetonitrile and added to the mixed solution. The reaction is performed at room temperature for 5.5 h, and then filtering, washing, and drying are performed to obtain the modified monomer.

[0023] Comparative Example 1: Commercially available silica aerogel (model number TF-41251, purchased from Suzhou Carbon Graphene Technology Co., Ltd.) is used, and the details are as follows: Step 1: After 90 parts of cement, 25 parts of silica fume, 110 parts of crushed stone, and 90 parts of fine sand are stirred and mixed, 40 parts of water, 19 parts of silica aerogel, and 1.5 parts of a water reducing agent (model number KT-01, purchased from Jilin Tosin Chemical Technology Co., Ltd.) are added and stirred and mixed to obtain a slurry; Step 2: After the slurry is cast and shaped, it is demolded after standing for 1.5 h, and then cut. After steam curing at 70°C for 7 days, and then standing at 22.5°C for 19 days, an aerogel block is obtained.

[0024] Comparative Example 2: No modified monomer is added, and the details are as follows: Step 1: 90 parts of cement, 25 parts of silica fume, 110 parts of crushed stone and 90 parts of fine sand are mixed, then 40 parts of water, 19 parts of modified silica aerogel and 1.5 parts of water reducing agent (model KT-01, purchased from Jilin Tuxin Chemical Technology Co., Ltd.) are added and mixed, to obtain a slurry; Step 2: After the slurry is poured and formed, it is demolded after 1.5h, then cut, and after 7 days of steam curing at 70℃, it is placed for 19 days at 22.5℃, to obtain the aerogel block; The preparation process of the modified silica aerogel is as follows: A1: The water glass and deionized water are mixed (the volume ratio of water glass to deionized water is 1:3), stirred uniformly, then dropped into a strong acid styrene cation exchange resin, the solution is collected, the pH is adjusted to 5 using ammonia water, stirred for 1.5min, then poured into a mold, aged at room temperature for 24h after being converted into a gel, and replaced twice with anhydrous ethanol, to obtain a silica wet gel; A2: The silica wet gel obtained in step A1 is added to a 3-methacryloxypropyltrimethoxysilane solution (the concentration of the 3-methacryloxypropyltrimethoxysilane solution is 37.5vol%), soaked for 24h, then reacted at 55℃ for 3.5h, after the reaction is completed, washed, to obtain an alkenylated silica wet gel; A3: 25.5 parts of acrylamide-2-methyl-1-propanesulfonic acid, 2.5 parts of maleic anhydride are added to 90 parts of N,N-dimethylformamide and stirred uniformly, then 65 parts of the alkenylated silica wet gel is added, placed for 24h, then moved into a 1.5 parts of azobisisobutyronitrile solution (the concentration of the azobisisobutyronitrile solution is 4.5wt%), soaked for 1.5h, then reacted at 75℃ for 3.5h, after the reaction is completed, washed, dried, to obtain the modified silica aerogel.

[0025] Detection test: (1) According to the standard GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete", the aerogel blocks obtained in the examples and the comparative examples are made into samples with a size of 100x100x100mm, to detect the tensile strength; (2) According to the standard JGJ51-2002 "Technical Specification for Lightweight Aggregate Concrete", the aerogel blocks obtained in the examples and the comparative examples are made into samples with a size of 300x300x300, to detect the thermal conductivity; the obtained data are shown in the following table: Conclusion: The aerogel block and the preparation method thereof provided by the present application significantly improve the mechanical properties and thermal insulation performance of the block by optimizing the formula and process.

[0026] The tensile strength of the examples one to three is 8.3 MPa, 8.5 MPa and 8.9 MPa respectively, which is much higher than that of the comparative example one (4.3 MPa) and the comparative example two (4.8 MPa), indicating that the introduction of modified silica aerogel and the use of modified monomers effectively enhance the structural stability of the block. At the same time, the thermal conductivity of the examples is between 0.021-0.028 W / m·K, which is significantly lower than that of the comparative example one (0.060 W / m·K) and the comparative example two (0.055 W / m·K), indicating that the porous structure of the modified aerogel is well maintained in the block, thereby significantly improving the thermal insulation performance. In addition, the phosphorus heterocyclic and thiadiazole groups in the modified monomers endow the aerogel with excellent flame retardance and chemical stability, further enhancing the practicability and durability of the block.

[0027] In summary, the present application successfully prepares aerogel blocks with high strength, low thermal conductivity and excellent functional properties through innovative formula design and process optimization, providing a high-performance solution for the building material field.

[0028] In the description of the specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0029] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as they do not deviate from the invention or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A method for preparing aerogel building blocks, characterized in that, Includes the following steps: Step 1: Mix cement, silica fume, crushed stone and fine sand, then add water, modified silica aerogel and water-reducing agent, and mix to obtain slurry; Step 2: After the slurry is poured into shape, it is allowed to stand for 1-2 hours before demolding. After cutting, it is steamed at 60-80℃ for 6-8 days, and then left to stand at 20-25℃ for 18-20 days to obtain aerogel blocks.

2. The method for preparing an aerogel block according to claim 1, characterized in that, The raw materials for preparing the slurry include the following components by weight: 80-100 parts cement, 20-30 parts silica fume, 100-120 parts crushed stone, 80-100 parts fine sand, 30-50 parts water, 18-20 parts modified silica aerogel, and 1-2 parts water-reducing agent.

3. The method for preparing an aerogel block according to claim 1, characterized in that, The preparation process of the modified silica aerogel is as follows: A1: Mix water glass with deionized water, stir evenly, and then drop it into a strong acid styrene-based cation exchange resin. Collect the solution, adjust the pH to 5 with ammonia, stir for 1-2 minutes, pour it into a mold, and after it is converted into a gel, age it at room temperature for 24 hours. Then replace it twice with anhydrous ethanol to obtain silica wet gel. A2: Add the silica wet gel obtained in step A1 to a 3-methacryloyloxypropyltrimethoxysilane solution and soak for 24 hours. Then react at 50-60℃ for 3-4 hours. After the reaction is complete, wash to obtain alkenylated silica wet gel. A3: Add the modified monomer, 2-acrylamido-2-methyl-1-propanesulfonic acid, and maleic anhydride to N,N-dimethylformamide and stir until homogeneous. Then add the alkenylated silica wet gel and let it stand for 24 hours. After that, transfer it to an azobisisobutyronitrile solution and soak for 1-2 hours. Then react at 70-80℃ for 3-4 hours. After the reaction is complete, wash and dry to obtain the modified silica aerogel.

4. The method for preparing an aerogel block according to claim 3, characterized in that, In step A1, the volume ratio of water glass to deionized water is 1:

3.

5. The method for preparing an aerogel block according to claim 3, characterized in that, In step A2, the concentration of the 3-methacryloxypropyltrimethoxysilane solution is 37.5 vol.

6. The method for preparing an aerogel block according to claim 3, characterized in that, The raw materials for preparing the modified silica aerogel include the following components: by weight, 3-4 parts of modified monomer, 25-6 parts of acrylamido-2-methyl-1-propanesulfonic acid, 2-3 parts of maleic anhydride, 80-100 parts of N,N-dimethylformamide, 60-70 parts of alkenylated silica wet gel, and 1-2 parts of azobisisobutyronitrile solution; the concentration of the azobisisobutyronitrile solution is 4-5 wt%.

7. The method for preparing an aerogel block according to claim 3, characterized in that, The preparation process of the modified monomer is as follows: S1: Mix 2-amino-1,3,4-thiadiazole with ethanol, raise the temperature to 50°C, stir for 10-15 min, then add p-hydroxybenzaldehyde, raise the temperature to 90°C, reflux and stir for 8-10 h, then add 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, maintain 90°C and continue the reaction for 10-12 h. After the reaction is completed, cool to room temperature, and perform post-processing to obtain intermediate A; S2: Mix intermediate A, sodium hydroxide and water, stir for 3-5 min to obtain a mixed solution; then dissolve acryloyl chloride in acetonitrile and add it to the mixed solution, react at room temperature for 5-6 h, filter, wash and dry to obtain the modified monomer.

8. The method for preparing an aerogel block according to claim 7, characterized in that, The raw materials for preparing intermediate A include the following components: by weight, 8-10 parts of amino-1,3,4-thiadiazole, 80-100 parts of ethanol, 12-15 parts of p-hydroxybenzaldehyde, and 20-22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

9. The method for preparing an aerogel block according to claim 7, characterized in that, The raw materials for preparing the modified monomer include the following components: by weight, 10-12 parts intermediate A, 0.5-1 parts sodium hydroxide, 20-30 parts water, 1-2 parts acryloyl chloride, and 20-30 parts acetonitrile.

10. An aerogel block obtained by the preparation method of an aerogel block according to any one of claims 1-9.

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