A phthalonitrile resin-based carbon aerogel and a preparation method and application thereof

Abstract

The application provides a phthalonitrile resin-based carbon aerogel and a preparation method and application thereof, and belongs to the technical field of aerogel materials.The preparation method of the phthalonitrile resin-based carbon aerogel comprises the following steps: S1, phthalonitrile monomers and a curing agent are melt-mixed to obtain a phthalonitrile resin prepolymer; S2, the phthalonitrile resin prepolymer is mixed with a water-soluble salt and then is subjected to crushing and grinding to obtain a mixture; and S3, the mixture is subjected to mold forming, curing, pyrolysis carbonization, removal of the water-soluble salt and drying to obtain the phthalonitrile resin-based carbon aerogel.The phthalonitrile resin-based carbon aerogel provided by the application has the characteristics of low shrinkage, high porosity, low density, low thermal conductivity, high electrical conductivity and the like, and can be used in the fields of sewage treatment, electromagnetic shielding, thermal insulation, and supercapacitors.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aerogel materials, in particular to a phthalonitrile resin-based carbon aerogel and a preparation method and application thereof. BACKGROUND

[0002] Carbon aerogels have high strength, large porosity, small pore size, large specific surface area, and low high-temperature thermal conductivity, and have broad application prospects in the fields of catalyst carriers, capacitors, and adsorption materials. The existing preparation method of carbon aerogels generally uses an aerogel precursor to obtain an organic aerogel through sol-gel, solvent exchange, and drying, and then obtains a carbon aerogel through pyrolysis carbonization. However, in the process of pyrolysis carbonization of the organic aerogel, the size of the aerogel is often greatly shrunk, which affects the shape stability and use reliability of the aerogel material. SUMMARY

[0003] In view of one or more technical problems in the prior art, the present application provides a phthalonitrile resin-based carbon aerogel and a preparation method and application thereof. The phthalonitrile resin-based carbon aerogel provided by the present application has low shrinkage, high porosity, low density, low thermal conductivity, and high electrical conductivity, and can be used in the fields of wastewater treatment, electromagnetic shielding, thermal insulation, and supercapacitors.

[0004] In a first aspect, the present application provides a preparation method of a phthalonitrile resin-based carbon aerogel, which comprises the following steps:

[0005] S1. Melting and mixing phthalonitrile monomers and a curing agent to obtain a phthalonitrile resin prepolymer;

[0006] S2. Grinding and crushing the phthalonitrile resin prepolymer and a water-soluble salt after mixing to obtain a mixture; the water-soluble salt accounts for 70-95% of the total mass of the mixture, and the phthalonitrile resin prepolymer accounts for 5-30% of the total mass of the mixture;

[0007] S3. Molding, curing, pyrolysis carbonization, removing the water-soluble salt, and drying the mixture to obtain the phthalonitrile resin-based carbon aerogel.

[0008] Preferably, the phthalonitrile monomers account for 85-95% and the curing agent accounts for 5-15% based on the total mass of the phthalonitrile monomers and the curing agent; preferably, the curing agent is an aromatic amine curing agent.

[0009] Preferably, the melting point of the water-soluble salt is not lower than the temperature of the pyrolysis carbonization; preferably, the water-soluble salt is one or more of sodium chloride, sodium sulfate, sodium carbonate, potassium sulfate, and magnesium sulfate.

[0010] Preferably, the mixture further comprises short fibers.

[0011] Preferably, the short fibers account for 0.1-10% of the total mass of the mixture; preferably, the length of the short fibers is 0.5-5mm;

[0012] Preferably, the short fibers are one or more of carbon fibers, glass fibers, ceramic fibers, and metal fibers.

[0013] Preferably, the pressure of the mold forming is 15-35MPa; and / or

[0014] The temperature of the solidification is 250-350℃, and the time is 12-24h.

[0015] Preferably, the pyrolysis carbonization is to raise the temperature to 800-1200℃ under a protective atmosphere and maintain the temperature for 1-2h; preferably, the temperature rising rate during the pyrolysis carbonization is 3-15℃ / min; and / or

[0016] The water-soluble salt is removed by water washing.

[0017] The present application provides, in a second aspect, a phthalonitrile resin-based carbon aerogel prepared by the method of the first aspect.

[0018] Preferably, the linear shrinkage of the phthalonitrile resin-based carbon aerogel is less than 10%;

[0019] The density of the phthalonitrile resin-based carbon aerogel is 50-300mg / cm 3 ;

[0020] The thermal conductivity of the phthalonitrile resin-based carbon aerogel is 0.02-0.06W / (m·K);

[0021] The specific surface area of the phthalonitrile resin-based carbon aerogel is 20-200m 2 / g;

[0022] The compression modulus of the phthalonitrile resin-based carbon aerogel is 10-50MPa; and / or

[0023] The room temperature conductivity of the phthalonitrile resin-based carbon aerogel is 10 -2 -10 3 S / m.

[0024] The present application provides, in a third aspect, an application of the phthalonitrile resin-based carbon aerogel of the second aspect, for wastewater treatment, electromagnetic shielding, thermal insulation, and supercapacitor fields.

[0025] Compared with the prior art, the present application has at least the following beneficial effects:

[0026] The present application takes phthalonitrile resin as the precursor of carbon aerogel, and uses water-soluble salt as the template. The salt template particles are uniformly mixed with the phthalonitrile resin prepolymer, and then the mixture is molded, cured, pyrolyzed and carbonized, and the water-soluble salt is removed, and finally dried to obtain carbon aerogel. In the whole preparation process of carbon aerogel, the water-soluble salt particles are used as the template, which can not only act as a pore-forming agent but also adjust the viscosity of the mixture during the curing process, shape the resin, reduce the shrinkage rate of carbon aerogel during pyrolysis and carbonization, and improve the shape stability of carbon aerogel. In addition, the water-soluble salt template is easy to remove. Moreover, the whole preparation process does not introduce solvent, which can further reduce the shrinkage rate of carbon aerogel during pyrolysis and carbonization and improve the shape stability of carbon aerogel.

[0027] The preparation process of the phthalonitrile resin-based carbon aerogel provided by the present application is simple, low in cost, environmentally friendly, and suitable for industrial large-scale production and application. Compared with the existing method of "first sol-gel, solvent replacement, and drying to prepare organic aerogel, and then pyrolysis and carbonization" to prepare carbon aerogel, the carbon aerogel prepared by the preparation method of the present application has a lower pyrolysis and carbonization shrinkage rate and better shape stability, and the salt template can be recycled, which can effectively reduce the production cost. In addition, by adjusting the pyrolysis and carbonization temperature, the electrical conductivity of the phthalonitrile resin-based carbon aerogel can be controlled to meet different needs and broaden its application scenarios.

[0028] The phthalonitrile resin-based carbon aerogel provided by the present application has low shrinkage rate, high porosity, low density, low thermal conductivity, and high electrical conductivity, and can be used in the fields of wastewater treatment, electromagnetic shielding, thermal insulation, and supercapacitors. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0030] Figure 1 is the actual process diagram and SEM microstructure diagram of the phthalonitrile resin-based carbon aerogel prepared in Example 1 of the present application;

[0031] Figure 2 is the XRD spectrum of the phthalonitrile resin-based carbon aerogel prepared in Example 1 of the present application;

[0032] Figure 3 is the Raman spectrum of the phthalonitrile resin-based carbon aerogel prepared in Example 1 of the present application;

[0033] Figure 4 is a SEM microstructure diagram of a phthalonitrile resin-based carbon aerogel prepared in Example 2 of the present application;

[0034] Figure 5 is a Raman spectrum diagram of a phthalonitrile resin-based carbon aerogel prepared in Example 2 of the present application. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0036] The present application provides, in a first aspect, a preparation method of a phthalonitrile resin-based carbon aerogel, the preparation method comprising the following steps:

[0037] S1. Melting and mixing phthalonitrile monomers and a curing agent to obtain a phthalonitrile resin prepolymer;

[0038] S2. Mixing the phthalonitrile resin prepolymer and a water-soluble salt and then performing pulverizing and grinding to obtain a mixture; the water-soluble salt accounts for 70-95% (for example, it can be 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95%) of the total mass of the mixture, and the phthalonitrile resin prepolymer accounts for 5-30% (for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%) of the total mass of the mixture;

[0039] S3. Performing mold forming, curing, pyrolysis carbonization, water-soluble salt removal and drying on the mixture to obtain the phthalonitrile resin-based carbon aerogel.

[0040] The present application takes phthalonitrile resin as a precursor of carbon aerogel, and uses water-soluble salt as a template. After the salt template particles are uniformly mixed with the phthalonitrile resin prepolymer, the mixture is molded, solidified, pyrolyzed and carbonized, and the water-soluble salt is removed, to obtain the carbon aerogel. In the whole preparation process of the carbon aerogel, the water-soluble salt particles are used as the template, which can not only act as a pore-forming agent but also adjust the viscosity of the mixture during the solidification process, shape the resin, reduce the shrinkage rate of the carbon aerogel during pyrolysis and carbonization, and improve the shape stability of the carbon aerogel. In addition, the water-soluble salt template is easy to remove. Moreover, the whole preparation process does not introduce solvents, which can further reduce the shrinkage rate of the carbon aerogel during pyrolysis and carbonization and improve the shape stability of the carbon aerogel.

[0041] Compared with the existing method of preparing carbon aerogel by "first preparing organic aerogel through sol-gel, solvent replacement and drying, and then pyrolyzing and carbonizing", the carbon aerogel prepared by the method of the present application has a lower pyrolysis and carbonization shrinkage rate and better shape stability. In addition, the salt template can be recycled, which can effectively reduce the production cost. Moreover, the conductivity of the phthalonitrile resin-based carbon aerogel can be adjusted by adjusting the pyrolysis and carbonization temperature, which can meet different needs and broaden its application scenarios.

[0042] In the present application, the phthalonitrile monomer and the curing agent are first mixed to ensure that the phthalonitrile and the curing agent are better mixed, to ensure more uniform curing of the prepolymer and to prevent local curing speed from being uneven.

[0043] In addition, the inventors of the present application found that if the content of water-soluble salt in the mixture is too low (less than 70%), the viscosity of the mixture is too small during the solidification process, and the molded mixture collapses under the action of gravity and cannot be shaped. In addition, too little water-soluble salt is easily wrapped by the resin matrix, and the salt template cannot be removed by water washing, so that the carbon aerogel block cannot be obtained. If the content of water-soluble salt in the mixture is too large (more than 95%), the connection strength of the phthalonitrile resin matrix is low, and the process of removing the salt template by water washing after pyrolysis and carbonization will cause the aerogel to crack, and a perfect carbon aerogel block cannot be obtained.

[0044] According to some preferred embodiments, the phthalonitrile monomer accounts for 85-95% (for example, it can be 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95%) and the curing agent accounts for 5-15% (for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%) based on the total mass of the phthalonitrile monomer and the curing agent. Preferably, the curing agent is an aromatic amine curing agent.

[0045] According to some preferred embodiments, the structural general formula of the phthalonitrile monomer is shown as formula (I), wherein R is a group comprising at least one benzene ring;

[0046]

[0047] According to some preferred embodiments, the melting point of the water-soluble salt is not lower than the temperature of the pyrolysis carbonization, preferably, the water-soluble salt is one or more of sodium chloride, sodium sulfate, sodium carbonate, potassium sulfate, and magnesium sulfate. The inventors select inorganic salts with a melting point not lower than the temperature of the pyrolysis carbonization as the salt template, which can adjust the viscosity of the mixture during the solidification process, and play a better shape-preserving role for the resin, and more effectively reduce the shrinkage of the carbon aerogel, and improve the shape stability of the carbon aerogel. The inventors have found that if the melting point of the selected water-soluble salt is too low, it is not conducive to obtaining a carbon aerogel block during the pyrolysis carbonization process.

[0048] According to some preferred embodiments, the mixture further comprises short-cut fibers.

[0049] According to some preferred embodiments, the short-cut fibers account for 0.1-10% (for example, can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%) of the total mass of the mixture; preferably, the length of the short-cut fibers is 0.5-5mm (for example, can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm); preferably, the short-cut fibers are one or more of carbon fibers, glass fibers, ceramic fibers, and metal fibers.

[0050] The present application can further improve the mechanical properties of the aerogel by adding short-cut fibers to the mixture.

[0051] According to some preferred embodiments, the pressure of the compression molding is 15-35MPa (for example, can be 15MPa, 16MPa, 17MPa, 18MPa, 19MPa, 20MPa, 21MPa, 22MPa, 23MPa, 24MPa, 25MPa, 26MPa, 27MPa, 28MPa, 29MPa, 30MPa, 31MPa, 32MPa, 33MPa, 34MPa, or 35MPa); and / or

[0052] The temperature for the solidification is 250-350℃ (for example, it can be 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃ or 350℃), and the time is 12-24h (for example, it can be 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h or 24h).

[0053] According to some preferred embodiments, the pyrolysis carbonization is to raise the temperature to 800-1200℃ (for example, it can be 800℃, 820℃, 850℃, 860℃, 880℃, 900℃, 920℃, 950℃, 960℃, 980℃, 1000℃, 1020℃, 1050℃, 1060℃, 1100℃, 1120℃, 1140℃, 1150℃, 1160℃, 1180℃ or 1200℃) and keep the temperature for 1-2h (for example, it can be 1h, 1.2h, 1.5h, 1.6h, 1.8h or 2h) under a protective atmosphere, preferably, the temperature raising rate during the pyrolysis carbonization is 3-15℃ / min (for example, it can be 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min or 15℃ / min); and / or

[0054] The water-soluble salt is recycled by water washing and recrystallization through water evaporation.

[0055] The present application can realize the regulation of the thermal conductivity of carbon aerogel by adjusting the temperature of pyrolysis carbonization, and can meet the demand of different application scenarios for the electrical conductivity of aerogel, and enrich the application range of the resorcinol formaldehyde resin-based carbon aerogel. The inventors found that if the pyrolysis carbonization temperature is too low, the prepared carbon aerogel has low graphitization degree and low room temperature electrical conductivity, and cannot be applied to application scenarios based on electrical conductivity.

[0056] The present application further comprises a drying step after removing the water-soluble salt.

[0057] The present application provides, in a second aspect, a resorcinol formaldehyde resin-based carbon aerogel prepared by the preparation method of the first aspect.

[0058] The pore size of the porous structure in the carbon aerogel of the resorcinol formaldehyde resin-based carbon aerogel is 10nm-5μm, including mesopores with a pore size of 10-50nm and macropores with a pore size of 50nm-5μm.

[0059] According to some preferred embodiments, the linear shrinkage of the phthalonitrile resin-based carbon aerogel is less than 10%;

[0060] According to some preferred embodiments, the density of the phthalonitrile resin-based carbon aerogel is 50-300 mg / cm 3 ;

[0061] According to some preferred embodiments, the thermal conductivity of the phthalonitrile resin-based carbon aerogel is 0.02-0.06 W / (m·K);

[0062] According to some preferred embodiments, the specific surface area of the phthalonitrile resin-based carbon aerogel is 20-200 m 2 / g;

[0063] According to some preferred embodiments, the compression modulus of the phthalonitrile resin-based carbon aerogel is 10-50 MPa; and / or

[0064] According to some preferred embodiments, the room temperature conductivity of the phthalonitrile resin-based carbon aerogel is 10 -2 -10 3 S / m.

[0065] The present application provides, in a third aspect, an application of the phthalonitrile resin-based carbon aerogel of the second aspect, in the fields of wastewater treatment, electromagnetic shielding, thermal insulation, supercapacitors.

[0066] The phthalonitrile resin-based carbon aerogel provided by the present application has low shrinkage, high porosity, low density, low thermal conductivity, high conductivity and the like, and can be used in the fields of wastewater treatment, electromagnetic shielding, thermal insulation, supercapacitors.

[0067] In order to more clearly illustrate the technical solutions and advantages of the present application, the present application will be further described below in conjunction with examples. The source of each reagent used in the examples and comparative examples of the present application is not specifically limited, and can be directly purchased or synthesized by oneself.

[0068] The test method or reference standard for each performance of the phthalonitrile resin-based carbon aerogel prepared in the examples and comparative examples of the present application is as follows:

[0069] The volume density is calculated according to the mass and volume of the aerogel; the specific surface area of the aerogel is tested by BET specific surface area testing method; the thermal conductivity of the aerogel is tested by Hotdisk thermal constant analyzer; and the conductivity of the sheet material pressed from the carbon aerogel powder is tested by four-point probe.

[0070] Example 1

[0071] A preparation method of a phthalonitrile resin-based carbon aerogel, comprising the following steps:

[0072] S1. Mix 14 g of phthalonitrile monomer (as shown in the following figure) and 1 g of aromatic amine curing agent, and heat to 210°C to melt and mix uniformly, and after cooling, obtain a phthalonitrile resin prepolymer;

[0073]

[0074] S2. Put 80 g of sodium chloride into a high-speed pulverizer together with the phthalonitrile resin prepolymer, and pulverize and mix for 5 min to obtain a uniformly mixed mixture;

[0075] S3. Transfer the mixture to a mold for molding at a molding pressure of 20 MPa, and place the molded block in a high-temperature oven for curing, with a curing program of 260°C for 4 h, 280°C for 4 h, 300°C for 4 h, 325°C for 4 h, and 350°C for 4 h; then transfer the cured block material into a tube furnace, heat to 800°C at a heating rate of 5°C / min under a nitrogen atmosphere, and keep for 2 h for pyrolytic carbonization; finally, take out the cooled pyrolytic carbonization material, remove the salt template by soaking in water, and dry after fully soaking to remove the salt template, to obtain a phthalonitrile-based carbon aerogel.

[0076] The phthalonitrile resin-based carbon aerogel prepared in this example has a density of 170 mg / cm 3 , a linear shrinkage of 2.8%, a room-temperature thermal conductivity of 0.026 W / (m·K), a specific surface area of 42 m 2 / g, and a room-temperature electrical conductivity of 0.93 S / m.

[0077] The physical diagram of the preparation process of the phthalonitrile resin-based carbon aerogel of this example and the SEM microstructure of the phthalonitrile resin-based carbon aerogel are shown in Figure 1 , the XRD spectrum of the phthalonitrile resin-based carbon aerogel of this example is shown in Figure 2 , the (002) and (100) crystal orientations of the graphitized carbon in the figure prove the carbon structure in the prepared carbon aerogel; the Raman spectrum of the phthalonitrile resin-based carbon aerogel of this example is shown in Figure 3 , and the strong G peak and D peak in the figure indicate the carbon structure in the prepared carbon aerogel material.

[0078] Example 2

[0079] A method for preparing a phthalonitrile resin-based carbon aerogel, comprising the following steps:

[0080] S1. Mix 14 g of phthalonitrile monomer (as shown in the following figure) and 1 g of aromatic amine curing agent, and heat to 210°C to melt and mix uniformly, and after cooling, obtain a phthalonitrile resin prepolymer;

[0081]

[0082] S2. Put 80 g of potassium sulfate into a high-speed pulverizer together with the above phthalonitrile resin prepolymer, and pulverize and mix for 5 min to obtain a uniformly mixed mixture;

[0083] S3. Transfer the mixture into a mold for compression molding at a molding pressure of 25 MPa, and place the molded block in a high-temperature oven for curing according to the following curing program: 260°C for 4 h, 280°C for 4 h, 300°C for 4 h, 325°C for 4 h, and 350°C for 4 h. Then, transfer the cured block material into a tube furnace, heat to 1000°C at a heating rate of 5°C / min under a nitrogen atmosphere, and keep the temperature for 1 h for pyrolytic carbonization. Finally, take out the cooled pyrolytic carbonization material, remove the salt template by soaking in water, and dry after removing the salt template to obtain a phthalonitrile-based carbon aerogel.

[0084] The phthalonitrile resin-based carbon aerogel prepared in this example has a density of 240 mg / cm 3 , a linear shrinkage of 3.3%, a room-temperature thermal conductivity of 0.038 W / (m·K), a specific surface area of 33 m 2 / g, and a room-temperature electrical conductivity of 2.7 S / m.

[0085] The SEM microstructure of the phthalonitrile resin-based carbon aerogel prepared in this example is shown in Figure 4 ; and the Raman spectrum of the phthalonitrile resin-based carbon aerogel prepared in this example is shown in Figure 5 , in which the strong G peak and D peak indicate the carbon structure of the prepared carbon aerogel material.

[0086] Example 3

[0087] A method for preparing a phthalonitrile resin-based carbon aerogel, comprising the following steps:

[0088] S1. Mix 15 g of phthalonitrile monomer (as shown in the following figure) and 1.5 g of aromatic amine curing agent, and heat to 210°C to melt and mix uniformly to obtain a phthalonitrile resin prepolymer;

[0089]

[0090] S2. Put 75 g of potassium sulfate and 1.5 g of chopped glass fiber into a high-speed pulverizer together with the above phthalonitrile resin prepolymer, and pulverize and mix for 5 min to obtain a uniformly mixed mixture;

[0091] S3. The mixture is transferred into a mold for compression molding, the molding pressure is 25 MPa; and the molded block is placed in a high-temperature oven for curing, the curing procedure is: 260℃ for 4h, 280℃ for 4h, 300℃ for 4h, 325℃ for 4h, 350℃ for 4h; then the cured block material is transferred into a tube furnace, and pyrolytic carbonization is carried out at 900℃ under nitrogen atmosphere at a heating rate of 10℃ / min for 1h; finally, the cooled carbonized material is taken out, the salt template is removed by placing it in water, and after sufficient soaking to remove the salt template, drying is carried out, and the phthalonitrile-based carbon aerogel is obtained.

[0092] The density of the phthalonitrile resin-based carbon aerogel prepared in this example is 235 mg / cm 3 , the linear shrinkage is 2.8%, the room temperature thermal conductivity is 0.04 W / (m·K); the specific surface area is 33 m 2 / g; and the room temperature electrical conductivity is 1.4 S / m.

[0093] Comparative Example 1

[0094] The same as Example 1, the only difference is that in S2, the mass of sodium chloride is 25g.

[0095] In this comparative example, the mixture after compression molding softens and collapses during the curing process, and the cured resin composite material has an irregular shape. Due to the serious wrapping of the salt template by the resin, the salt template cannot be removed during the water washing process after carbonization, the material has a large density and fewer microporous structures, and therefore cannot be called an aerogel.

[0096] Comparative Example 2

[0097] The same as Example 1, the only difference is that in S3, the pyrolytic carbonization temperature is 700℃.

[0098] This comparative example can prepare a light aerogel material, but due to the low pyrolytic carbonization temperature, the carbonization degree of the organic components in the aerogel is not enough, and the measured room temperature electrical conductivity is less than 10 -6 S / m, which cannot be used in the application field of carbon aerogel based on the electrical conductivity of the material.

[0099] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a phthalonitrile resin-based carbon aerogel, characterized by, The preparation method comprises the following steps: S1. Melting and mixing phthalonitrile monomers and a curing agent to obtain a phthalonitrile resin prepolymer; S2. Mixing the phthalonitrile resin prepolymer and a water-soluble salt and then performing pulverizing and grinding to obtain a mixture; the water-soluble salt accounts for 70-95% of the total mass of the mixture, and the phthalonitrile resin prepolymer accounts for 5-30% of the total mass of the mixture; the melting point of the water-soluble salt is not lower than the temperature of pyrolytic carbonization, and the water-soluble salt is one or more of sodium chloride, sodium sulfate, sodium carbonate, potassium sulfate, and magnesium sulfate; S3. Performing mold pressing, curing, pyrolytic carbonization, water-soluble salt removal, and drying on the mixture to obtain the phthalonitrile resin-based carbon aerogel; the pyrolytic carbonization is to raise the temperature to 800-1200 DEG C under a protective atmosphere and keep the temperature for 1-2 h, and the temperature rising rate in the pyrolytic carbonization process is 3-15 DEG C / min.

2. The production method according to claim 1, characterized by, The phthalonitrile monomers account for 85-95% of the total mass of the phthalonitrile monomers and the curing agent, and the curing agent accounts for 5-15%.

3. The preparation method according to claim 1, characterized in that, The curing agent is an aromatic amine curing agent.

4. The method of claim 1, wherein, The mixture further comprises chopped fibers.

5. The production method according to claim 4, characterized by, The chopped fibers account for 0.1-10% of the total mass of the mixture.

6. The preparation method according to claim 4, characterized in that, The length of the chopped fibers is 0.5-5 mm.

7. The preparation method according to claim 4, characterized in that, The chopped fibers are one or more of carbon fibers, glass fibers, ceramic fibers, and metal fibers.

8. The method of claim 1, wherein, The pressure of the mold pressing is 15-35 MPa.

9. The method of claim 1, wherein, The temperature of the curing is 250-350 DEG C, and the time is 12-24 h.

10. The method of claim 1, wherein, The water-soluble salt removal is performed by water washing.

11. A phthalonitrile resin-based carbon aerogel, characterized in that, The phthalonitrile resin-based carbon aerogel is prepared by the preparation method in any one of claims 1-10.

12. The carbogel based on phthalonitrile resin according to claim 11, characterized in that, The linear shrinkage of the phthalonitrile resin-based carbon aerogel is less than 10%; The density of the phthalonitrile resin-based carbon aerogel is 50-300 mg / cm 3 ; The thermal conductivity of the phthalonitrile resin-based carbon aerogel is 0.02-0.06 W / (m·K); The specific surface area of the phthalonitrile resin-based carbon aerogel is 20-200 m 2 / g; The compression modulus of the phthalonitrile resin-based carbon aerogel is 10-50 MPa; and / or The room temperature conductivity of the phthalonitrile resin based carbon aerogel is 10 -2 ~10 3 S / m.

13. Use of the phthalonitrile resin-based carbon aerogel according to any one of claims 11-12, characterized in that, The phthalonitrile resin-based carbon aerogel is used in the fields of sewage treatment, electromagnetic shielding, thermal insulation, and supercapacitors.

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