Aerogel with heat insulation function and preparation method thereof

Abstract

The invention discloses aerogel with a heat preservation and heat insulation function and a preparation method thereof.The method comprises the steps that urea and metal hydrate are evenly mixed, imidazolium salt is added, and a precursor solution is formed; the molar ratio of the urea to the metal hydrate is (5: 80)-(7: 40); the molar ratio of the urea to the imidazolium salt is (5: 6)-(7: 3); dissolving graphene oxide in a solvent to obtain a graphene oxide solution; the ratio of the mass of the graphene oxide to the volume of the solvent is (1-2): (30-40) g / ml; adding a sodium hydroxide solution, a surfactant and alkylphenol polyoxyethylene ether into the graphene oxide solution to form an intermediate solution; and sequentially adding inorganic salt and the precursor solution into the intermediate solution, and reacting at 70-80 DEG C to obtain the aerogel with the thermal insulation function. The thermal insulation performance of the aerogel is improved.

Description

Technical Field

[0001] The present invention relates to the field of materials, and in particular to an aerogel with thermal insulation functions and a preparation method thereof. Background Art

[0002] Building thermal insulation materials, especially high-efficiency ones, are a key way to alleviate building energy consumption and promote sustainable economic development. Aerogel, a new, high-efficiency thermal insulation material, has found practical application in aerospace and civil insulation applications. Currently, commonly used SiO2 aerogel materials are inherently brittle and prone to flakes and slag. Furthermore, the preparation process for SiO2 aerogel composites is relatively complex and costly, hindering their widespread application in the construction sector. Therefore, the development and production of environmentally friendly, low-cost, high-performance thermal insulation materials is of paramount importance. Summary of the Invention

[0003] The present invention provides an aerogel with thermal insulation function and a preparation method thereof. The aerogel has low density and thermal conductivity, high pore volume and porosity, and thus has good thermal insulation performance.

[0004] In one aspect, the present invention provides a method for preparing an aerogel having thermal insulation functions, the method comprising:

[0005] After uniformly mixing urea and metal hydrate, imidazole salt is added to form a precursor solution; the molar ratio of the urea to the metal hydrate is (5:80)-(7:40); the molar ratio of the urea to the imidazole salt is (5:6)-(7:3);

[0006] dissolving graphene oxide in a solvent to obtain a graphene oxide solution; wherein the mass ratio of the graphene oxide to the solvent is (1-2): (30-40) g / ml;

[0007] Adding a sodium hydroxide solution, a surfactant, and an alkylphenol polyoxyethylene ether to the graphene oxide solution to form an intermediate solution; the mass ratio of the surfactant to the graphene oxide is (1:4)-(1:1), and the mass ratio of the surfactant to the alkylphenol polyoxyethylene ether is (1:2)-(1:6);

[0008] Inorganic salt and the precursor solution are sequentially added to the intermediate solution, and reacted at 70-80° C. to obtain an aerogel with thermal insulation function.

[0009] In an exemplary embodiment, the inorganic salt and the precursor solution are sequentially added to the intermediate solution, and reacted at 70-80° C. to obtain an aerogel having thermal insulation function, comprising:

[0010] adding the inorganic salt and the precursor solution to the intermediate solution in sequence, and reacting at 70-80° C. for 2-3 hours to obtain an initial product;

[0011] The initial product is dialyzed using a water-ethanol solution until a transparent solution is obtained;

[0012] The transparent solution is sealed in a high-pressure reactor. After the reaction is completed, the material in the high-pressure reactor is taken out and freeze-dried to obtain an aerogel with thermal insulation function.

[0013] In an exemplary embodiment, the dialysate used in the dialysis treatment has a volume ratio of water to ethanol of 9:1.

[0014] In an exemplary embodiment, the reaction temperature in the high-pressure reactor is 190-200°C.

[0015] In an exemplary embodiment, the transparent solution is sealed in a high-pressure reactor, and after the reaction is completed, the substance in the high-pressure reactor is taken out and freeze-dried to obtain an aerogel with thermal insulation function, comprising:

[0016] The transparent solution is sealed in a high-pressure reactor and subjected to heat insulation treatment for 5-6 hours;

[0017] placing the high-pressure reactor at room temperature for cooling;

[0018] The material in the high-pressure reactor is taken out and freeze-dried to obtain an aerogel with thermal insulation function.

[0019] In an exemplary embodiment, the freezing temperature in the freeze-drying process is -20°C to -10°C.

[0020] In an exemplary embodiment, the step of adding a sodium hydroxide solution, a surfactant, and an alkylphenol polyoxyethylene ether to the graphene oxide solution to form an intermediate solution comprises:

[0021] Continuously adding sodium hydroxide solution to the graphene oxide solution until the pH of the mixed solution reaches 9;

[0022] Adding surfactant and alkylphenol polyoxyethylene ether to the mixed solution in sequence, stirring evenly to form the intermediate solution.

[0023] In an exemplary embodiment, the metal hydrate is at least one of sodium tetrahydroxyaluminate, hexaamminecobalt trichloride, and zinc nitrate hexahydrate; the imidazole salt is at least one of 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, and 1-ethyl-3-methylimidazolium tetrafluoroborate; the solvent is at least one of deionized water, ethanol, and ethylene glycol; the surfactant is at least one of benzothiazole disulfide, N-cyclohexyl-2-benzothiazolesulfenamide, and tetramethylthiuram disulfide; and the inorganic salt is at least one of magnesium fluorosilicate, bentonite, and sodium silicate.

[0024] In an exemplary embodiment, the mass ratio of the inorganic salt to the graphene oxide is (1:1)-(3:1), and the volume ratio of the mass of the inorganic salt to the precursor solution is (2-3):(10-15) g / ml.

[0025] In an exemplary embodiment, the mass ratio of the inorganic salt to the graphene oxide is (1:1)-(3:1), and the volume ratio of the mass of the inorganic salt to the precursor solution is (2-3):(10-15) g / ml.

[0026] On the other hand, the present invention provides an aerogel with thermal insulation function, wherein the aerogel is obtained by the preparation method according to any one of claims 1 to 9, the aerogel is a three-dimensional hollow interconnected structure, the thermal conductivity of the aerogel is ≤0.0399 W / m·K, and the porosity of the aerogel is ≥86.3%.

[0027] The present invention has the following beneficial effects:

[0028] The aerogel produced by the present invention exhibits hydrophobicity and excellent mechanical properties, making it suitable for use in a variety of scenarios. The aerogel produced by the present invention has a porous network structure, possesses abundant network skeleton strength, and has controllable shrinkage. The aerogel has low density and thermal conductivity, high pore volume and porosity, and thus exhibits excellent thermal insulation properties.

[0029] 2. The preparation method of the present invention is simple, has mild conditions, is easy to control, and the raw materials used are all non-toxic or low-toxic raw materials. The raw material consumption during the reaction is small, the cost is low, and no toxic by-products are generated. It is an environmentally friendly synthesis method. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 This is a preparation flow chart of a flame-retardant transparent fiber composite material provided by an embodiment of the present invention.

[0032] Figure 2 3 is a scanning electron microscope image of the aerogel prepared in the embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] It should also be noted here that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0035] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0036] With the continuous progress of society and the rapid development of the economy, energy consumption has increased accordingly. Among them, building energy consumption accounts for more than 10% of the world's total energy consumption. Such a large amount of building energy consumption has also caused serious impacts on the environment. More than half of the building energy consumption is caused by the poor thermal insulation effect of building glass and wall materials. Therefore, the research and development of building thermal insulation materials with excellent properties such as low thermal conductivity, low apparent density, non-combustibility, and good durability is an important topic for energy conservation and consumption reduction today. Aerogel has become a research hotspot in recent years due to its high specific surface area, high porosity and excellent chemical stability. This embodiment provides an aerogel with thermal insulation function and a preparation method thereof, which can improve the thermal insulation performance of aerogel.

[0037] Example 1

[0038] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing an aerogel having thermal insulation function, the method comprising:

[0039] S1: After uniformly mixing urea and metal hydrate, adding imidazole salt to form a precursor solution; the molar ratio of the urea to the metal hydrate is (5:80)-(7:40); the molar ratio of the urea to the imidazole salt is (5:6)-(7:3);

[0040] The primary purpose of introducing the imidazole salt in this example is to impart good network strength and controllable shrinkage to the resulting aerogel. The strong van der Waals forces between graphene sheets facilitate stacking and agglomeration, thus preventing the pores in the resulting aerogel from collapsing. When added during the synthesis of thermal insulation materials, the imidazole salt tightly bonds with the graphene oxide nanosheets, weakening the interactions between the graphene sheets and stacking the graphene oxide sheets into a three-dimensional porous structure.

[0041] S2: dissolving graphene oxide in a solvent to obtain a graphene oxide solution; the mass ratio of the graphene oxide to the solvent is (1-2): (30-40) g / ml;

[0042] S3: adding a sodium hydroxide solution, a surfactant, and an alkylphenol polyoxyethylene ether to the graphene oxide solution to form an intermediate solution; the mass ratio of the surfactant to the graphene oxide is (1:4)-(1:1), and the mass ratio of the surfactant to the alkylphenol polyoxyethylene ether is (1:2)-(1:6);

[0043] In the embodiment of this specification, the step of adding a sodium hydroxide solution, a surfactant, and an alkylphenol polyoxyethylene ether to the graphene oxide solution to form an intermediate solution comprises:

[0044] Continuously adding sodium hydroxide solution to the graphene oxide solution until the pH of the mixed solution reaches 9;

[0045] Adding surfactant and alkylphenol polyoxyethylene ether to the mixed solution in sequence, stirring evenly to form the intermediate solution.

[0046] In the examples of this specification, the concentration of the sodium hydroxide solution is 6 mol / L, and the stirring time for forming the intermediate solution is 50-60 min. The alkylphenol polyoxyethylene ether mainly acts as a dispersant, allowing other substances to be evenly dispersed in the system without aggregation or agglomeration.

[0047] S4: adding an inorganic salt and the precursor solution to the intermediate solution in sequence, and reacting at 70-80°C to obtain an aerogel having thermal insulation function; the mass ratio of the inorganic salt to the graphene oxide is (1:1)-(3:1), and the volume ratio of the mass of the inorganic salt to the precursor solution is (2-3):(10-15) g / ml.

[0048] Exemplarily, the inorganic salt and the precursor solution are sequentially added to the intermediate solution, and reacted at 70-80° C. to obtain an aerogel having thermal insulation function, comprising:

[0049] adding the inorganic salt and the precursor solution to the intermediate solution in sequence, and reacting at 70-80° C. for 2-3 hours to obtain an initial product;

[0050] The initial product is dialyzed using a water-ethanol solution until a transparent solution is obtained;

[0051] The transparent solution is sealed in a high-pressure reactor. After the reaction is completed, the material in the high-pressure reactor is taken out and freeze-dried to obtain an aerogel with thermal insulation function.

[0052] In the examples of this specification, the volume ratio of water to ethanol in the dialysate used in the dialysis treatment is 9:1, and the reaction temperature in the high-pressure reactor is 190-200°C.

[0053] In the embodiment of this specification, the transparent solution is sealed in a high-pressure reactor, and after the reaction is completed, the substance in the high-pressure reactor is taken out and freeze-dried to obtain an aerogel with thermal insulation function, including:

[0054] The transparent solution is sealed in a high-pressure reactor and subjected to heat insulation treatment for 5-6 hours;

[0055] placing the high-pressure reactor at room temperature for cooling;

[0056] The material in the high-pressure reactor is taken out and freeze-dried to obtain an aerogel with thermal insulation function.

[0057] In the examples of this specification, the freezing temperature in the freeze-drying process is -20°C to -10°C.

[0058] In the examples of this specification, the metal hydrate is at least one of sodium tetrahydroxyaluminate, hexaamminecobalt trichloride, and zinc nitrate hexahydrate; the imidazole salt is at least one of 1-ethyl-3-methylimidazole ethyl sulfate, 1-ethyl-3-methylimidazole diethyl phosphate, and 1-ethyl-3-methylimidazole tetrafluoroborate; the solvent is at least one of deionized water, ethanol, and ethylene glycol; the surfactant is at least one of benzothiazole disulfide, N-cyclohexyl-2-benzothiazolesulfenamide, and tetramethylthiuram disulfide; and the inorganic salt is at least one of magnesium fluorosilicate, bentonite, and sodium silicate.

[0059] Among them, the selection of surfactants is mainly to give the obtained aerogel super hydrophobicity. They can make the surface of the obtained aerogel rough and at the same time attach hydrophobic groups on its surface.

[0060] In the examples of this specification, the mass ratio of the inorganic salt to the graphene oxide is (1:1)-(3:1), and the volume ratio of the mass of the inorganic salt to the precursor solution is (2-3):(10-15) g / ml.

[0061] The aerogel with thermal insulation effect of this embodiment uses graphene oxide as the main raw material, uses metal hydrates and surfactants to enhance the electrostatic cross-linking between graphene oxide sheets and prevent stacking, and then uses alkylphenol polyoxyethylene ether and inorganic salts to modify it, so that the mesoporous layered nanosheets of graphene oxide are intertwined and supported by each other to form a large number of large pores. The aerogel is formed through bubble template optimization and has a low thermal conductivity coefficient and good thermal insulation performance.

[0062] The aerogel synthesis mechanism in this scheme involves first reacting a precursor solution, graphene oxide, a surfactant, and an inorganic salt to form a structure in which the imidazole salt and graphene oxide sheets are tightly bound, and other substances are bound to the graphene oxide surface. Next, the aerogel is dialyzed against a water and ethanol solution to remove moisture from the surface. The aerogel is then placed in an autoclave, where the high-pressure environment allows for the manipulation of the pore size. Finally, freeze-drying is used to freeze the water-containing material, forming solid ice. Sublimation then converts the water from ice to gas under low temperature and low pressure, leaving behind a dry, solid material. During this sublimation process, the structure and properties of the material are preserved, resulting in an aerogel with a unique structure.

[0063] Example 2

[0064] This embodiment provides a method for preparing an aerogel having thermal insulation effect, comprising the following steps:

[0065] The first step is to prepare a precursor solution: 5-7 ml of 0.1 mol / L urea and 10-20 ml of a metal hydrate solution are mixed and stirred continuously for 20-30 minutes. After the mixture is fully mixed, 1-2 ml of an imidazole salt is added and stirred for 10-20 minutes to obtain a precursor solution.

[0066] The second step involves preparing the thermal insulation material: 1-2g of graphene oxide (GO) is dissolved in 30-40ml of solvent. A 6mol / L sodium hydroxide solution is then added dropwise until the pH reaches 9. Subsequently, 0.5-1g of a surfactant and 2-3g of an alkylphenol polyoxyethylene ether are added, stirring continuously for 50-60 minutes. Next, 2-3g of an inorganic salt and 10-15ml of the precursor solution are added, and the mixture is reacted at 70-80°C for 2-3 hours to produce the thermal insulation material.

[0067] Exemplarily, the metal hydrate is sodium tetrahydroxyaluminate, hexaamminecobalt trichloride, or zinc nitrate hexahydrate; the imidazole salt is one of 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, or 1-ethyl-3-methylimidazolium tetrafluoroborate; the solvent is any one of deionized water, ethanol, or ethylene glycol; the surfactant is one of benzothiazole disulfide, N-cyclohexyl-2-benzothiazolesulfenamide, or tetramethylthiuram disulfide; the inorganic salt is one of magnesium fluorosilicate, bentonite, or sodium silicate;

[0068] Illustratively, the aerogel is obtained by dialyzing a thermal insulation material, insulating it in a high-pressure reactor, and then freeze-drying it.

[0069] For example, the material obtained in the second step can be dialyzed with a water-ethanol solution until the solution is transparent, and then the solution can be sealed in a high-pressure reactor. After the reaction is completed, the high-pressure reactor is cooled at room temperature, opened, and the substance therein is taken out and placed in a vacuum freeze dryer for freeze drying to obtain an aerogel.

[0070] Exemplarily, the volume ratio of water to ethanol in the dialysate used is 9:1; the reaction temperature in the high-pressure reactor is 190-200°C, and the heat insulation is maintained for 5-6 hours; and the freezing temperature is -20--10°C.

[0071] Example 3

[0072] This embodiment provides a method for preparing an aerogel having thermal insulation effect, comprising the following steps:

[0073] The first step is to prepare the precursor solution: 5 ml of 0.1 mol / L urea and 10 ml of metal hydrate sodium tetrahydroxyaluminate solution are mixed and stirred continuously for 20 minutes. After they are fully mixed, 1 ml of imidazole salt 1-ethyl-3-methylimidazolium ethyl sulfate is added thereto and stirred for 10 minutes to obtain a precursor solution.

[0074] The second step involved preparing the thermal insulation material: 1g of graphene oxide (GO) was dissolved in 30ml of deionized water. A 6mol / L sodium hydroxide solution was then added dropwise until the pH reached 9. Subsequently, 0.5g of the surfactant benzothiazole disulfide and 2g of alkylphenol polyoxyethylene ether were added, and the mixture was stirred continuously for 50 minutes. Next, 2g of the inorganic salt magnesium fluorosilicate and 10ml of the precursor solution were added, and the mixture was reacted at 70°C for 2h to produce the thermal insulation material.

[0075] In the third step, the material obtained in the second step is dialyzed with a water-ethanol solution until the solution is transparent, and then the solution is sealed in a high-pressure reactor and reacted at 190°C for 5 hours. After the reaction is completed, the high-pressure reactor is cooled at room temperature, opened, and the substance therein is taken out and placed in a vacuum freeze dryer for freeze drying at -20°C to obtain aerogel.

[0076] Example 4

[0077] This embodiment provides a method for preparing an aerogel having thermal insulation effect, comprising the following steps:

[0078] The first step is to prepare the precursor solution: 6 ml of 0.1 mol / L urea and 15 ml of metal hydrate sodium tetrahydroxyaluminate solution are mixed and stirred continuously for 25 minutes. After they are fully mixed, 1.5 ml of imidazole salt 1-ethyl-3-methylimidazolium ethyl sulfate is added thereto and stirred for 15 minutes to obtain a precursor solution.

[0079] The second step involved preparing the thermal insulation material: 1.5g of graphene oxide (GO) was dissolved in 35ml of deionized water. A 6mol / L sodium hydroxide solution was then added dropwise until the pH reached 9. Subsequently, 0.8g of the surfactant benzothiazole disulfide and 2.5g of alkylphenol polyoxyethylene ether were added, and the mixture was stirred continuously for 55 minutes. Next, 2.5g of the inorganic salt magnesium fluorosilicate and 13ml of the precursor solution were added, and the mixture was reacted at 75°C for 2.5 hours to produce the thermal insulation material.

[0080] In the third step, the material obtained in the second step is dialyzed with a water-ethanol solution until the solution is transparent, and then the solution is sealed in a high-pressure reactor and reacted at 195°C for 5.5 hours. After the reaction is completed, the high-pressure reactor is cooled at room temperature, opened, and the substance therein is taken out and placed in a vacuum freeze dryer for freeze drying at -15°C to obtain aerogel.

[0081] Example 5

[0082] This embodiment provides a method for preparing an aerogel having thermal insulation effect, comprising the following steps:

[0083] The first step is to prepare the precursor solution: 7 ml of 0.1 mol / L urea and 20 ml of metal hydrate sodium tetrahydroxyaluminate solution are mixed and stirred continuously for 30 minutes. After they are fully mixed, 2 ml of imidazole salt 1-ethyl-3-methylimidazolium ethyl sulfate is added thereto and stirred for 20 minutes to obtain a precursor solution.

[0084] The second step involved preparing the thermal insulation material: 2g of graphene oxide (GO) was dissolved in 40ml of deionized water. A 6mol / L sodium hydroxide solution was then added dropwise until the pH reached 9. Subsequently, 1g of the surfactant benzothiazole disulfide and 3g of alkylphenol polyoxyethylene ether were added, and the mixture was stirred continuously for 60 minutes. Next, 3g of the inorganic salt magnesium fluorosilicate and 15ml of the precursor solution were added, and the mixture was reacted at 80°C for 3 hours to produce the thermal insulation material.

[0085] In the third step, the material obtained in the second step is dialyzed with a water-ethanol solution until the solution is transparent, and then the solution is sealed in a high-pressure reactor and reacted at 200°C for 6 hours. After the reaction is completed, the high-pressure reactor is cooled at room temperature, opened, and the substance therein is taken out and placed in a vacuum freeze dryer for freeze drying at -10°C to obtain aerogel.

[0086] Comparative Example 1 (without adding precursor solution)

[0087] The first step involved preparing the thermal insulation material: 2g of graphene oxide (GO) was dissolved in 40ml of deionized water. A 6mol / L sodium hydroxide solution was then added dropwise until the pH reached 9. Subsequently, 1g of the surfactant benzothiazole disulfide and 3g of alkylphenol polyoxyethylene ether were added, and the mixture was stirred continuously for 60 minutes. Finally, 3g of the inorganic salt magnesium fluorosilicate was added, and the mixture was reacted at 80°C for 3 hours to produce the thermal insulation material.

[0088] In the second step, the material obtained in the first step is dialyzed with a water-ethanol solution until the solution is transparent, and then the solution is sealed in a high-pressure reactor and reacted at 200°C for 6 hours. After the reaction is completed, the high-pressure reactor is cooled at room temperature, opened, and the substance therein is taken out and placed in a vacuum freeze dryer for freeze drying at -10°C to obtain aerogel.

[0089] Comparative Example 2 (without adding surfactant benzothiazole disulfide and alkylphenol polyoxyethylene ether)

[0090] The first step is to prepare the precursor solution: 7 ml of 0.1 mol / L urea and 20 ml of metal hydrate sodium tetrahydroxyaluminate solution are mixed and stirred continuously for 30 minutes. After they are fully mixed, 2 ml of imidazole salt 1-ethyl-3-methylimidazolium ethyl sulfate is added thereto and stirred for 20 minutes to obtain a precursor solution.

[0091] The second step involved preparing the thermal insulation material: 2g of graphene oxide (GO) was dissolved in 40ml of deionized water, and a 6mol / L sodium hydroxide solution was added dropwise until the pH reached 9. 3g of the inorganic salt magnesium fluorosilicate and 15ml of the precursor solution were then added, and the mixture was reacted at 80°C for 3h to produce the thermal insulation material.

[0092] In the third step, the material obtained in the second step is dialyzed with a water-ethanol solution until the solution is transparent, and then the solution is sealed in a high-pressure reactor and reacted at 200°C for 6 hours. After the reaction is completed, the high-pressure reactor is cooled at room temperature, opened, and the substance therein is taken out and placed in a vacuum freeze dryer for freeze drying at -10°C to obtain aerogel.

[0093] Comparative Example 3 (without adding inorganic salt)

[0094] The first step is to prepare the precursor solution: 7 ml of 0.1 mol / L urea and 20 ml of metal hydrate sodium tetrahydroxyaluminate solution are mixed and stirred continuously for 30 minutes. After they are fully mixed, 2 ml of imidazole salt 1-ethyl-3-methylimidazolium ethyl sulfate is added thereto and stirred for 20 minutes to obtain a precursor solution.

[0095] The second step involved preparing the thermal insulation material: 2g of graphene oxide (GO) was dissolved in 40ml of deionized water. A 6mol / L sodium hydroxide solution was then added dropwise until the pH reached 9. Subsequently, 1g of the surfactant benzothiazole disulfide and 3g of alkylphenol polyoxyethylene ether were added, and the mixture was stirred continuously for 60 minutes. Finally, 15ml of the precursor solution was added, and the mixture was reacted at 80°C for 3 hours to produce the thermal insulation material.

[0096] In the third step, the material obtained in the second step is dialyzed with a water-ethanol solution until the solution is transparent, and then the solution is sealed in a high-pressure reactor and reacted at 200°C for 6 hours. After the reaction is completed, the high-pressure reactor is cooled at room temperature, opened, and the substance therein is taken out and placed in a vacuum freeze dryer for freeze drying at -10°C to obtain aerogel.

[0097] The results of testing the aerogels obtained in Examples 3-5 and Comparative Examples 1-3 are shown in Table 1 below:

[0098] Table 1

[0099]

[0100] It can be seen that the density of the aerogel obtained in this embodiment is less than that in the comparative example, and the density of the aerogel is ≤0.071 g / cm 3 The porosity of the aerogel obtained in this embodiment is much greater than that of the comparative example, and the porosity of the aerogel is ≥86.3%.

[0101] Example 6

[0102] This embodiment also provides an aerogel with thermal insulation function, the aerogel is obtained by the above-mentioned preparation method, the aerogel is a three-dimensional hollow interconnected structure, the thermal conductivity of the aerogel is ≤0.0399W / m·K, and the porosity of the aerogel is ≥86.3%. Figure 2 As shown, Figure 2 The scanning electron microscope image of the aerogel prepared in this embodiment; Figure 2 As can be seen from Figure a, the graphene aerogel composite material presents a three-dimensional hollow interconnected structure, and there are some microspheres on the surface of the graphene oxide sheet. These are the result of the inorganic salts, metals and surfactants gathering on the surface of the graphene oxide. At the same time, many wrinkles can be seen, which also confirms the principle of increasing surface roughness mentioned earlier. Figure 2 Middle B picture and Figure 2 As can be seen in Figure c, the formed hole is a three-dimensional hole structure. The hole has not collapsed, and the strength is high and the structure is complete.

[0103] The aerogel obtained in the present invention has excellent thermal insulation performance and can be widely used in important industrial production fields such as petrochemical pipelines, construction, ships, and aviation.

[0104] The aerogel produced by the present invention exhibits hydrophobicity and excellent mechanical properties, making it suitable for use in a variety of scenarios. The aerogel produced by the present invention has a porous network structure, possesses abundant network skeleton strength, and has controllable shrinkage. The aerogel has low density and thermal conductivity, high pore volume and porosity, and thus exhibits excellent thermal insulation properties.

[0105] 2. The preparation method of the present invention is simple, has mild conditions, is easy to control, and the raw materials used are all non-toxic or low-toxic raw materials. The raw material consumption during the reaction is small, the cost is low, and no toxic by-products are generated. It is an environmentally friendly synthesis method.

[0106] The above disclosures are merely some preferred embodiments of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for preparing aerogel with thermal insulation function, characterized in that: The method comprises: After uniformly mixing urea and metal hydrate, imidazole salt is added to form a precursor solution; the molar ratio of the urea to the metal hydrate is (5:80)-(7:40); the molar ratio of the urea to the imidazole salt is (5:6)-(7:3); dissolving graphene oxide in a solvent to obtain a graphene oxide solution; wherein the mass ratio of the graphene oxide to the solvent is (1-2): (30-40) g / ml; Adding a sodium hydroxide solution, a surfactant, and an alkylphenol polyoxyethylene ether to the graphene oxide solution to form an intermediate solution; the mass ratio of the surfactant to the graphene oxide is (1:4)-(1:1), and the mass ratio of the surfactant to the alkylphenol polyoxyethylene ether is (1:2)-(1:6); Inorganic salt and the precursor solution are sequentially added to the intermediate solution, and reacted at 70-80° C. to obtain an aerogel with thermal insulation function.

2. The preparation method according to claim 1, characterized in that The inorganic salt and the precursor solution are sequentially added to the intermediate solution, and reacted at 70-80° C. to obtain an aerogel having thermal insulation function, comprising: adding the inorganic salt and the precursor solution to the intermediate solution in sequence, and reacting at 70-80° C. for 2-3 hours to obtain an initial product; The initial product is dialyzed using a water-ethanol solution until a transparent solution is obtained; The transparent solution is sealed in a high-pressure reactor. After the reaction is completed, the material in the high-pressure reactor is taken out and freeze-dried to obtain an aerogel with thermal insulation function.

3. The preparation method according to claim 2, characterized in that The volume ratio of water to ethanol in the dialysate used in the dialysis treatment is 9:

1.

4. The preparation method according to claim 2, characterized in that The reaction temperature in the high-pressure reactor is 190-200°C.

5. The preparation method according to claim 2, characterized in that The transparent solution is sealed in a high-pressure reactor, and after the reaction is completed, the substance in the high-pressure reactor is taken out and freeze-dried to obtain an aerogel with thermal insulation function, comprising: The transparent solution is sealed in a high-pressure reactor and subjected to heat insulation treatment for 5-6 hours; placing the high-pressure reactor at room temperature for cooling; The material in the high-pressure reactor is taken out and freeze-dried to obtain an aerogel with thermal insulation function.

6. The preparation method according to claim 5, characterized in that The freezing temperature in the freeze-drying process is -20°C to -10°C.

7. The preparation method according to claim 1, characterized in that The step of adding a sodium hydroxide solution, a surfactant, and an alkylphenol polyoxyethylene ether to the graphene oxide solution to form an intermediate solution comprises: Continuously adding sodium hydroxide solution to the graphene oxide solution until the pH of the mixed solution reaches 9; Adding surfactant and alkylphenol polyoxyethylene ether to the mixed solution in sequence, stirring evenly to form the intermediate solution.

8. The preparation method according to claim 7, characterized in that The metal hydrate is at least one of sodium tetrahydroxyaluminate, hexaamminecobalt trichloride, and zinc nitrate hexahydrate; the imidazole salt is at least one of 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, and 1-ethyl-3-methylimidazolium tetrafluoroborate; the solvent is at least one of deionized water, ethanol, and ethylene glycol; the surfactant is at least one of benzothiazole disulfide, N-cyclohexyl-2-benzothiazolesulfenamide, and tetramethylthiuram disulfide; and the inorganic salt is at least one of magnesium fluorosilicate, bentonite, and sodium silicate.

9. The preparation method according to claim 1, characterized in that The mass ratio of the inorganic salt to the graphene oxide is (1:1)-(3:1), and the volume ratio of the mass of the inorganic salt to the precursor solution is (2-3):(10-15) g / ml.

10. An aerogel having thermal insulation function, characterized in that: The aerogel is obtained by the preparation method according to any one of claims 1 to 9. The aerogel is a three-dimensional hollow interconnected structure. The thermal conductivity of the aerogel is ≤0.0399 W / m·K, and the porosity of the aerogel is ≥86.3%.

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