An antiknock material and a method for producing the same

Abstract

This invention relates to an explosion-proof material and its preparation method, belonging to the field of safety engineering technology for explosion suppression. The preparation method of the explosion-proof material includes the following steps: First, an aramid nanofiber-silica composite aerogel is prepared. Then, isocyanate components and amino compounds are separately loaded into the raw material tank of a spraying machine, heated separately, mixed, and atomized under high pressure, and sprayed onto two surfaces of a substrate to form a polyurea coating. Next, an adhesive is sprayed onto one of the polyurea coating surfaces to bond and fix the aramid nanofiber-silica composite aerogel to the polyurea coating surface, serving as the explosion-facing side. The polyurea coating without the bonded aramid nanofiber-silica composite aerogel serves as the back side, thereby forming an explosion-proof material on the substrate surface. The explosion-proof material prepared in this invention has excellent impact resistance and flame retardant properties, can withstand multiple deflagration impacts, and can prevent debris generated by the substrate explosion from harming the surrounding environment and personnel.

Description

Technical Field

[0001] This invention belongs to the field of safety engineering technology for suppressing explosions, and specifically relates to an explosion-proof material and its preparation method. Background Technology

[0002] Hydrogen energy is widely recognized as the most promising clean energy source in the 21st century. However, during the production, storage, transportation, and use of hydrogen, when the hydrogen concentration reaches the flammability limit, the mixed gas may burn, deflagrate, or even detonate under certain conditions, causing serious damage and destruction to engineering structures such as bridges and buildings, resulting in significant casualties and property losses.

[0003] Polyurea coatings possess excellent explosion-proof properties, but they are not resistant to high temperatures and are flammable. During hydrogen deflagration, the polyurea coating will be burned by the flame, significantly reducing its explosion-proof performance. Silica aerogels have high porosity (>90%) and low density (0.003-0.1 g / cm³). 3 With its characteristics of high thermal conductivity (0.013-0.14 W / m·K), silica aerogel can absorb and buffer the impact energy generated by hydrogen deflagration. However, silica aerogel is brittle, has low mechanical strength and poor flexibility, and is not very effective as an anti-explosion material when used alone. Therefore, there is an urgent need for an anti-explosion material that has both excellent anti-explosion properties and good flame retardant properties. Summary of the Invention

[0004] The purpose of this invention is to provide an explosion-proof material and its preparation method. The method involves spraying a polyurea coating onto two surfaces of a substrate, then bonding and fixing an aramid nanofiber-silica composite aerogel to one of the polyurea coating surfaces as the explosion-facing side. The polyurea coating without the aramid nanofiber-silica composite aerogel serves as the back side. This invention, by fixing an explosion-proof material with excellent impact resistance and flame retardant properties onto the substrate surface, enables the substrate to resist hydrogen explosions, thereby effectively suppressing the hazards to the surrounding environment caused by hydrogen leakage and building explosion debris.

[0005] The technical problem this invention aims to solve is that while polyurea coatings possess excellent explosion-proof properties, they are not resistant to high temperatures and are flammable. During hydrogen deflagration, the polyurea coating is burned by the flame, significantly reducing its explosion-proof performance. Silica aerogel, on the other hand, has high porosity (>90%) and low density (0.003-0.1 g / cm³). 3 With its characteristics of low thermal conductivity (0.013-0.14 W / m·K), silica aerogel can absorb and buffer the impact energy generated by hydrogen deflagration. However, silica aerogel is brittle, has low mechanical strength and poor flexibility, and is not very effective as an anti-explosion material when used alone.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] An explosion-proof polyurea coating and its preparation method include the following steps:

[0008] A1. Hydroxylated aramid nanofiber hydrogels were prepared by hydroxylating aramid nanofibers with silane coupling agents: silane coupling agents were dissolved in dimethyl sulfoxide to obtain a mixed solution. Aramid nanofibers and potassium hydroxide were added to the mixed solution and magnetically stirred at room temperature for 5-7 days to obtain an aramid nanofiber dispersion. The aramid nanofiber dispersion was added to dimethyl sulfoxide, and then deionized water was added. The solvent was exchanged three times, each time for 1-2 days, to obtain hydroxylated aramid nanofiber hydrogels.

[0009] A2. The hydroxylated aramid nanofiber hydrogel was placed in a supercritical drying device and subjected to supercritical drying to obtain hydroxylated aramid nanofiber aerogel.

[0010] A3. Depositing silica on hydroxylated aramid nanofiber aerogel using chemical vapor deposition to obtain aramid nanofiber-silica composite aerogel: The hydroxylated aramid nanofiber aerogel was placed in a desiccator and tetraethyl orthosilicate and ammonia were introduced respectively. Silica was deposited on the hydroxylated aramid nanofiber aerogel using chemical vapor deposition at 25-30℃ and 18-23kPa to obtain aramid nanofiber-silica composite aerogel.

[0011] In the preparation processes of steps A1, A2, and A3 above, this invention first modifies aramid nanofibers using a silane coupling agent to obtain hydroxylated aramid nanofiber aerogel. Then, using chemical vapor deposition (CVD), tetraethyl orthosilicate is reacted with ammonia water to deposit silica on the surface of the hydroxylated aramid nanofibers. The silanol groups of silica and the hydroxyl groups of the hydroxylated aramid nanofibers undergo a dehydration condensation reaction, causing silica to be grafted onto the surface of the aramid nanofibers in the form of chemical bonds. The resulting silica coating layer is more uniform and robust. Aramid is a high-temperature resistant material with excellent mechanical properties and toughness. Using aramid nanofiber aerogel as a carrier can improve the toughness of silica, making the aramid nanofiber-silica composite aerogel more impact-resistant and with superior flame-retardant properties.

[0012] A4. Spray a polyurea coating onto both surfaces of the substrate. Then, bond and fix aramid nanofiber-silica composite aerogel to one of the polyurea coating surfaces as the blast-facing surface. The polyurea coating without the bonded aramid nanofiber-silica composite aerogel serves as the back surface, thereby forming an blast-resistant material on the substrate surface. Clean the substrate surface, load the isocyanate component and amino compound into the raw material tank of the spraying machine, heat them separately, mix them, and spray them onto both surfaces of the substrate through high-pressure atomization to form a polyurea coating. Then, spray an adhesive onto one of the polyurea coating surfaces to bond and fix the aramid nanofiber-silica composite aerogel to the polyurea coating surface as the blast-facing surface. The polyurea coating without the bonded aramid nanofiber-silica composite aerogel serves as the back surface, thereby forming an blast-resistant material on the substrate surface.

[0013] In the above preparation process, this invention coats polyurea onto two surfaces of a substrate and bonds and fixes aramid nanofiber-silica composite aerogel to one of the polyurea coating surfaces as the blast-facing surface. When hydrogen deflagrates, the flame spreads to the surface of the aramid nanofiber-silica composite aerogel. The aramid nanofibers in the aramid nanofiber-silica composite aerogel carbonize after high-temperature combustion and are encapsulated by the silica layer, forming a barrier layer to prevent the polyurea coating from being burned and damaged. During the hydrogen deflagration, in addition to combustion, a detonation shock wave is also generated. The shock wave is absorbed and buffered when it passes through the aramid nanofiber-silica composite aerogel layer. A portion of the shock wave is absorbed when it passes through the polyurea coating, and the remaining portion is absorbed by the substrate and the polyurea coating on the back side. The polyurea coating on the back side can act as a restraint layer, and its excellent flexibility can encapsulate fragments, preventing fragments generated by the substrate explosion from causing harm to the surrounding environment and personnel. Due to the protection of the aramid nanofiber-silica composite aerogel, the polyurea coating is not easily burned by the flame, so the explosion-resistant material prepared by this invention can withstand multiple explosion impacts.

[0014] Further, in step A1, the volume ratio of silane coupling agent to dimethyl sulfoxide in the mixed solution is 0.12-0.23:1; the silane coupling agent is 3-aminopropyltriethoxysilane; and the mass-volume ratio of aramid nanofibers, potassium hydroxide, and the mixed solution is 12-15g:16-20g:1-1.3L.

[0015] Furthermore, in step A2, during the supercritical drying process, the drying medium is CO2, the drying temperature is 55-65℃, the drying pressure is 14-16MPa, and the holding time is 1-2h.

[0016] Furthermore, in step A3, the volume ratio of tetraethyl orthosilicate to ammonia is 3-4:20, and the reaction deposition time is 6-10 hours.

[0017] Furthermore, in step A4, the molar ratio of the isocyanate component to the amino compound is 1.1-1.2:1; the heating temperature is 28-32℃.

[0018] Furthermore, in step A4, the thickness of the polyurea coating on the explosion-facing side is 3-5 mm; the thickness of the polyurea coating on the back side is 6-8 mm; and the thickness of the aramid nanofiber-silica composite aerogel is 7-10 mm.

[0019] Furthermore, the substrate includes devices for transporting or storing hydrogen, such as pipes and concrete walls.

[0020] The explosion-proof material was prepared using the method described above.

[0021] The beneficial effects of this invention are:

[0022] (1) In the technical solution of the present invention, silica is grafted onto the surface of aramid nanofiber in the form of chemical bonds, and the resulting silica coating layer is more uniform and firm. Aramid is a high temperature resistant material with excellent mechanical properties and toughness. Using aramid nanofiber aerogel as a carrier can improve the toughness of silica, making the aramid nanofiber-silica composite aerogel more impact resistant, and the flame retardant properties of silica coating aramid are more excellent.

[0023] (2) In the technical solution of the present invention, the polyurea coating and the aramid nanofiber-silica composite aerogel are sequentially adhered to the surface of the substrate and serve as the explosion-proof surface. When hydrogen is deflagrated, the flame spreads to the surface of the aramid nanofiber-silica composite aerogel. The aramid nanofibers in the aramid nanofiber-silica composite aerogel are carbonized after high-temperature combustion and are wrapped by the silica layer to form a barrier layer, preventing the polyurea coating from being burned and damaged. Therefore, the explosion-proof material prepared by the present invention can resist multiple deflagration impacts.

[0024] (3) In the technical solution of this invention, during the hydrogen deflagration process, in addition to combustion, a detonation shock wave is also generated. The shock wave is absorbed and buffered when it passes through the porous material of the aramid nanofiber-silica composite aerogel layer. When the shock wave passes through the polyurea coating, a portion is absorbed again, and the remaining portion is absorbed by the substrate and the polyurea coating on the back. The multiple strong interface structures improve the explosion resistance of the substrate. The polyurea coating on the back can serve as a restraint layer, and its excellent flexibility can wrap the fragments, preventing the fragments generated by the substrate explosion from causing harm to the surrounding environment and personnel. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] An explosion-proof polyurea coating and its preparation method include the following steps:

[0028] A1. Dissolve 1.2 L of 3-aminopropyltriethoxysilane in 10 L of dimethyl sulfoxide to obtain a mixed solution. Add 120 g of aramid nanofibers and 160 g of potassium hydroxide to 10 L of the above mixed solution and stir magnetically at room temperature for 5 days to obtain an aramid nanofiber dispersion. Add the aramid nanofiber dispersion to 65 L of dimethyl sulfoxide, then add 80 L of deionized water. Perform solvent exchange 3 times, 1 day each time, to obtain a hydroxylated aramid nanofiber hydrogel.

[0029] A2. The hydroxylated aramid nanofiber hydrogel was placed in a supercritical drying device for supercritical drying. During the supercritical drying process, the drying medium was CO2, the drying temperature was 55℃, the drying pressure was 14MPa, and the holding time was 1h to obtain hydroxylated aramid nanofiber aerogel.

[0030] A3. The hydroxylated aramid nanofiber aerogel was placed in a desiccator and tetraethyl orthosilicate and ammonia water with a volume ratio of 3:20 were introduced respectively. Silica was deposited on the hydroxylated aramid nanofiber aerogel by chemical vapor deposition at 25℃ and 18kPa for 6 hours to obtain aramid nanofiber-silica composite aerogel.

[0031] A4. Clean the surface of the concrete wall and coat both surfaces with an epoxy-modified polyurethane primer. Load the isocyanate component (CDMDI-100L) and amino compound (Versalink P-1000) in a 1.1:1 molar ratio into the raw material tank of the sprayer. Heat each component to 28°C, mix, and atomize under high pressure. Spray the mixture onto both surfaces of the concrete wall to form a polyurea coating. Then, spray a layer of polyurethane adhesive onto one of the polyurea coating surfaces to bond and fix the aramid nanofiber-silica composite aerogel to the polyurea coating surface, serving as the explosion-proof side. The polyurea coating without the bonded aramid nanofiber-silica composite aerogel serves as the back side, thus forming an explosion-proof material on the substrate surface. The thickness of the polyurea coating on the explosion-proof side is 3mm; the thickness of the polyurea coating on the back side is 6mm; and the thickness of the aramid nanofiber-silica composite aerogel is 7mm.

[0032] Example 2

[0033] An explosion-proof polyurea coating and its preparation method include the following steps:

[0034] A1. Dissolve 1.4 L of 3-aminopropyltriethoxysilane in 10 L of dimethyl sulfoxide to obtain a mixed solution. Add 130 g of aramid nanofibers and 160 g of potassium hydroxide to 10 L of the above mixed solution and stir magnetically at room temperature for 6 days to obtain an aramid nanofiber dispersion. Add the aramid nanofiber dispersion to 65 L of dimethyl sulfoxide, then add 80 L of deionized water. Perform solvent exchange 3 times, 1 day each time, to obtain a hydroxylated aramid nanofiber hydrogel.

[0035] A2. The hydroxylated aramid nanofiber hydrogel was placed in a supercritical drying device for supercritical drying. During the supercritical drying process, the drying medium was CO2, the drying temperature was 60℃, the drying pressure was 15MPa, and the holding time was 1h to obtain hydroxylated aramid nanofiber aerogel.

[0036] A3. The hydroxylated aramid nanofiber aerogel was placed in a desiccator and tetraethyl orthosilicate and ammonia water with a volume ratio of 3.2:20 were introduced respectively. Silica was deposited on the hydroxylated aramid nanofiber aerogel by chemical vapor deposition at 28℃ and 19kPa for 7h to obtain aramid nanofiber-silica composite aerogel.

[0037] A4. Clean the surface of the concrete wall and coat both surfaces with an epoxy-modified polyurethane primer. Load the isocyanate component (CDMDI-100L) and amino compound (Versalink P-1000) in a 1.15:1 molar ratio into the raw material tank of the spraying machine. Heat each component to 29°C, mix them, and then atomize them under high pressure before spraying them onto both surfaces of the concrete wall to form a polyurea coating. Next, spray a layer of polyurethane adhesive onto one of the polyurea coating surfaces to bond and fix the aramid nanofiber-silica composite aerogel to the polyurea coating surface, serving as the explosion-proof side. The polyurea coating without the bonded aramid nanofiber-silica composite aerogel serves as the back side, thus forming an explosion-proof material on the substrate surface. The thickness of the polyurea coating on the explosion-proof side is 4mm; the thickness of the polyurea coating on the back side is 7mm; and the thickness of the aramid nanofiber-silica composite aerogel is 8mm.

[0038] Example 3

[0039] An explosion-proof polyurea coating and its preparation method include the following steps:

[0040] A1. Dissolve 1.6 L of 3-aminopropyltriethoxysilane in 10 L of dimethyl sulfoxide to obtain a mixed solution. Add 140 g of aramid nanofibers and 180 g of potassium hydroxide to 11 L of the above mixed solution and stir magnetically at room temperature for 6 days to obtain an aramid nanofiber dispersion. Add the aramid nanofiber dispersion to 65 L of dimethyl sulfoxide, then add 80 L of deionized water. Perform solvent exchange 3 times, 2 days each time, to obtain a hydroxylated aramid nanofiber hydrogel.

[0041] A2. The hydroxylated aramid nanofiber hydrogel was placed in a supercritical drying device for supercritical drying. During the supercritical drying process, the drying medium was CO2, the drying temperature was 65℃, the drying pressure was 16MPa, and the holding time was 2h to obtain the hydroxylated aramid nanofiber aerogel.

[0042] A3. The hydroxylated aramid nanofiber aerogel was placed in a desiccator and tetraethyl orthosilicate and ammonia water with a volume ratio of 3.4:20 were introduced respectively. Silica was deposited on the hydroxylated aramid nanofiber aerogel by chemical vapor deposition at 30℃ and 20kPa for 8 hours to obtain aramid nanofiber-silica composite aerogel.

[0043] A4. Clean the surface of the concrete wall and coat both surfaces with an epoxy-modified polyurethane primer. Load the isocyanate component (CDMDI-100L) and amino compound (Versalink P-1000) in a 1.2:1 molar ratio into the raw material tank of the spraying machine. Heat each component to 32°C, mix them, and then atomize them under high pressure before spraying them onto both surfaces of the concrete wall to form a polyurea coating. Next, spray a layer of polyurethane adhesive onto one of the polyurea coating surfaces to bond and fix the aramid nanofiber-silica composite aerogel to the polyurea coating surface, serving as the explosion-proof side. The polyurea coating without the bonded aramid nanofiber-silica composite aerogel serves as the back side, thus forming an explosion-proof material on the substrate surface. The thickness of the polyurea coating on the explosion-proof side is 5mm; the thickness of the polyurea coating on the back side is 8mm; and the thickness of the aramid nanofiber-silica composite aerogel is 9mm.

[0044] Example 4

[0045] An explosion-proof polyurea coating and its preparation method include the following steps:

[0046] A1. Dissolve 1.8 L of 3-aminopropyltriethoxysilane in 10 L of dimethyl sulfoxide to obtain a mixed solution. Add 150 g of aramid nanofibers and 160 g of potassium hydroxide to 11 L of the above mixed solution and stir magnetically at room temperature for 7 days to obtain an aramid nanofiber dispersion. Add the aramid nanofiber dispersion to 65 L of dimethyl sulfoxide, then add 80 L of deionized water. Perform solvent exchange 3 times, 2 days each time, to obtain a hydroxylated aramid nanofiber hydrogel.

[0047] A2. The hydroxylated aramid nanofiber hydrogel was placed in a supercritical drying device for supercritical drying. During the supercritical drying process, the drying medium was CO2, the drying temperature was 60℃, the drying pressure was 15MPa, and the holding time was 2h to obtain hydroxylated aramid nanofiber aerogel.

[0048] A3. The hydroxylated aramid nanofiber aerogel was placed in a desiccator and tetraethyl orthosilicate and ammonia water with a volume ratio of 3.8:20 were introduced respectively. Silica was deposited on the hydroxylated aramid nanofiber aerogel by chemical vapor deposition at 30℃ and 21kPa for 9 hours to obtain aramid nanofiber-silica composite aerogel.

[0049] A4. Clean the surface of the concrete wall and coat both surfaces with an epoxy-modified polyurethane primer. Load the isocyanate component (CDMDI-100L) and amino compound (Versalink P-1000) in a 1.2:1 molar ratio into the raw material tank of the spraying machine. Heat each component to 32°C, mix, and atomize under high pressure. Spray the mixture onto both surfaces of the concrete wall to form a polyurea coating. Then, spray a layer of polyurethane adhesive onto one of the polyurea coating surfaces to bond and fix the aramid nanofiber-silica composite aerogel to the polyurea coating surface, serving as the explosion-proof side. The polyurea coating without the bonded aramid nanofiber-silica composite aerogel serves as the back side, thus forming an explosion-proof material on the substrate surface. The thickness of the polyurea coating on the explosion-proof side is 3mm; the thickness of the polyurea coating on the back side is 8mm; and the thickness of the aramid nanofiber-silica composite aerogel is 10mm.

[0050] Example 5

[0051] An explosion-proof polyurea coating and its preparation method include the following steps:

[0052] A1. Dissolve 2.3 L of 3-aminopropyltriethoxysilane in 10 L of dimethyl sulfoxide to obtain a mixed solution. Add 150 g of aramid nanofibers and 200 g of potassium hydroxide to 12 L of the above mixed solution and stir magnetically at room temperature for 7 days to obtain an aramid nanofiber dispersion. Add the aramid nanofiber dispersion to 70 L of dimethyl sulfoxide, then add 80 L of deionized water. Perform solvent exchange 3 times, 2 days each time, to obtain a hydroxylated aramid nanofiber hydrogel.

[0053] A2. The hydroxylated aramid nanofiber hydrogel was placed in a supercritical drying device for supercritical drying. During the supercritical drying process, the drying medium was CO2, the drying temperature was 60℃, the drying pressure was 15MPa, and the holding time was 2h to obtain hydroxylated aramid nanofiber aerogel.

[0054] A3. The hydroxylated aramid nanofiber aerogel was placed in a desiccator and tetraethyl orthosilicate and ammonia water with a volume ratio of 3.5:20 were introduced respectively. Silica was deposited on the hydroxylated aramid nanofiber aerogel by chemical vapor deposition at 28℃ and 23kPa for 10h to obtain aramid nanofiber-silica composite aerogel.

[0055] A4. Clean the surface of the concrete wall and coat both surfaces with an epoxy-modified polyurethane primer. Load the isocyanate component (CDMDI-100L) and amino compound (Versalink P-1000) in a 1.1:1 molar ratio into the raw material tank of the sprayer. Heat each component to 32°C, mix, and atomize under high pressure. Spray the mixture onto both surfaces of the concrete wall to form a polyurea coating. Then, spray a layer of polyurethane adhesive onto one of the polyurea coating surfaces to bond and fix the aramid nanofiber-silica composite aerogel to the polyurea coating surface, serving as the explosion-proof side. The polyurea coating without the bonded aramid nanofiber-silica composite aerogel serves as the back side, thus forming an explosion-proof material on the substrate surface. The thickness of the polyurea coating on the explosion-proof side is 5mm; the thickness of the polyurea coating on the back side is 6mm; and the thickness of the aramid nanofiber-silica composite aerogel is 9mm.

[0056] Comparative Example 1

[0057] Compared with Example 3, Comparative Example 1 did not use silane coupling agent to modify aramid nanofibers, while other steps and raw materials were the same as in Example 3.

[0058] Comparative Example 2

[0059] Compared with Example 3, no silica was deposited on the hydroxylated aramid nanofiber aerogel in Comparative Example 2, while other steps and raw materials were the same as in Example 3.

[0060] Comparative Example 3

[0061] Compared with Example 3, the aramid nanofiber-silica composite aerogel was not bonded to the explosion-facing surface in Comparative Example 3, while the other steps and raw materials were the same as in Example 3.

[0062] The performance of the aerogel materials prepared in Examples 1-5 and Comparative Examples 1-2 was tested, and the results are shown in Table 1.

[0063] Performance testing:

[0064] (1) Mechanical properties: Tensile stress-strain curves were recorded using an Instron 5565A universal testing machine at 40% humidity and 25°C with a loading rate of 5 mm / min. All aerogel materials were cut into samples with a length and width of 20 mm and 5 mm, respectively.

[0065] (2) Flame retardant performance: The limiting oxygen index was determined according to GB / T 2406.2-2009 "Determination of burning behavior of plastics by oxygen index method - Part 2: Room temperature test".

[0066] Table 1

[0067]

[0068]

[0069] As can be seen from the data in Table 1, the aramid nanofiber-silica composite aerogel prepared in this invention exhibits excellent flame retardant properties. Specifically, comparing Example 3 with Comparative Examples 1 and 2, it can be seen that the flame retardant properties were improved after modification with a silane coupling agent, and the deposition of silica also enhanced the flame retardant properties of the composite aerogel.

[0070] The explosion-proof performance of the explosion-proof materials prepared in Examples 1-5 and Comparative Examples 1-3 was tested, and the results are shown in Table 2.

[0071] Blast resistance test: The concrete wall thickness is 24cm, the blast load is applied using the CONWEP function, the TNT equivalent is 2.56g, and the blast distance is 10.5cm.

[0072] Table 2

[0073] project Explosion-proof performance improvement index / % Example 1 37.4 Example 2 36.7 Example 3 39.2 Example 4 38.3 Example 5 38.7 Comparative Example 1 35.6 Comparative Example 2 30.2 Comparative Example 3 28.8

[0074] As can be seen from the data in Table 2, the explosion-proof material prepared by this invention has excellent explosion-proof performance. Specifically, comparing Example 3 with Comparative Examples 1 and 2, it can be seen that the modification of aramid nanofibers by the silane coupling agent and the deposition of silica improve the explosion-proof performance of the explosion-proof material; comparing Example 3 with Comparative Example 3, it can be seen that the adhesion of the aramid nanofiber-silica composite aerogel improves the explosion-proof performance of the explosion-proof material.

[0075] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0076] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for producing an antiknock material, characterized by, Includes the following steps: A1. Hydroxylated aramid nanofiber hydrogels were prepared by hydroxylating aramid nanofibers with silane coupling agents. A2. The hydroxylated aramid nanofiber hydrogel was placed in a supercritical drying device and subjected to supercritical drying to obtain hydroxylated aramid nanofiber aerogel. A3. Silica was deposited on hydroxylated aramid nanofiber aerogel using chemical vapor deposition technology to obtain aramid nanofiber-silica composite aerogel. A4. Spray a polyurea coating on both surfaces of the substrate, and then bond and fix aramid nanofiber-silica composite aerogel to one of the polyurea coating surfaces as the explosion-proof surface. The polyurea coating without the aramid nanofiber-silica composite aerogel bonded and fixed is used as the back surface, thereby forming an explosion-proof material on the substrate surface.

2. The method of claim 1, wherein the anti-knock material is prepared by the steps of: The specific preparation process of the hydroxylated aramid nanofiber hydrogel is as follows: a silane coupling agent is dissolved in dimethyl sulfoxide solvent to obtain a mixed solution; aramid nanofibers and potassium hydroxide are added to the above mixed solution; the mixture is magnetically stirred at room temperature for 5-7 days to obtain an aramid nanofiber dispersion; the aramid nanofiber dispersion is added to dimethyl sulfoxide, and then deionized water is added; the solvent is exchanged 3 times, each time for 1-2 days, to obtain the hydroxylated aramid nanofiber hydrogel.

3. A method of preparing an antiknock material according to claim 2, wherein The volume ratio of silane coupling agent to dimethyl sulfoxide in the mixed solution is 0.12-0.23:1; the silane coupling agent is 3-aminopropyltriethoxysilane; the mass-volume ratio of aramid nanofibers, potassium hydroxide and the mixed solution is 12-15g:16-20g:1-1.3L.

4. The method of claim 1, wherein the anti-knock material is prepared by the steps of: In step A2, during the supercritical drying process, the drying medium is CO2, the drying temperature is 55-65℃, the drying pressure is 14-16MPa, and the heat and pressure holding time is 1-2h.

5. The method for preparing an anti-explosion material according to claim 1, characterized in that, The specific preparation process of aramid nanofiber-silica composite aerogel is as follows: hydroxylated aramid nanofiber aerogel is placed in a desiccator, and tetraethyl orthosilicate and ammonia are introduced respectively. Silica is deposited on the hydroxylated aramid nanofiber aerogel by chemical vapor deposition at 25-30℃ and 18-23kPa to obtain aramid nanofiber-silica composite aerogel.

6. A method of preparing an antiknock material according to claim 5, wherein The volume ratio of tetraethyl orthosilicate to ammonia is 3-4:20, and the reaction deposition time is 6-10 hours.

7. The method of claim 1, wherein the anti-knock material is prepared by the steps of: The specific operation process of step A4 is as follows: clean the surface of the substrate, load the isocyanate component and amino compound into the raw material barrel of the spraying machine, heat them separately, mix them and spray them onto the two surfaces of the substrate through high pressure atomization to form a polyurea coating; then spray an adhesive onto one of the polyurea coating surfaces to bond and fix the aramid nanofiber-silica composite aerogel to the polyurea coating surface as the explosion-proof surface; A polyurea coating with aramid nanofiber-silica composite aerogel not bonded to it is used as the back side, thereby forming an explosion-proof material on the substrate surface.

8. A method of preparing an antiknock material according to claim 7, wherein In step A4, the molar ratio of isocyanate component to amino compound is 1.1-1.2:1; the heating temperature is 28-32℃.

9. The method for preparing an anti-explosion material according to claim 7, characterized in that, In step A4, the thickness of the polyurea coating on the explosion-facing side is 3-5 mm; the thickness of the polyurea coating on the back side is 6-8 mm; and the thickness of the aramid nanofiber-silica composite aerogel is 7-10 mm.

10. An explosion-proof material prepared by the method according to any one of claims 1-9.