Flame-retardant hydrophobic aerogel material as well as preparation method and application thereof

Abstract

The invention relates to a flame-retardant hydrophobic aerogel material as well as a preparation method and application thereof. The method comprises the following steps: carrying out heat treatment on an aerogel material to be treated; depositing a nano oxide layer on the surface of the aerogel material subjected to heat treatment; converting the nano oxide layer on the surface of the aerogel material into a partial masking layer; converting the partial masking layer on the surface of the aerogel material into a dual-effect partial masking layer; and carrying out vacuum gas phase modification on the aerogel material with the double-effect partial masking layer, and then carrying out post-treatment. The nano masking layer is prepared on the surface of an aerogel nanoparticle skeleton through atomic layer deposition and is converted into a double-effect partial masking layer with a flame-retardant effect, hydrophobic groups are selectively and partially modified by utilizing the surface property difference between the partial masking layer and partially exposed aerogel nanoparticles, and the hydrophobic groups are selectively and partially modified by utilizing the surface property difference between the partial masking layer and the partially exposed aerogel nanoparticles. The introduction amount of combustible substances can be effectively controlled, and the flame-retardant hydrophobic characteristic is generated by combining the decomposition of the double-effect partial masking layer at high temperature and the flame-retardant effect of heat absorption.

Description

Technical Field

[0001] The present invention belongs to the field of thermal insulation materials, and in particular relates to a flame retardant hydrophobic aerogel material and a preparation method and application thereof. Background Art

[0002] In order to ensure the long-term use of aerogel materials, introducing hydrophobic organic groups into the aerogel to impart hydrophobicity is a widely used approach. However, due to the flammability of organic groups, when hydrophobic aerogel materials are exposed to high temperature environments or open flames, they are prone to combustion and smoke generation, which limits the scope of use of hydrophobic aerogel materials and poses a potential fire hazard. Therefore, in order to reduce the flammability of hydrophobic aerogels to a certain extent, flame retardant ingredients can be introduced during the preparation process of hydrophobic aerogel materials to reduce the potential combustion heat release of hydrophobic aerogels. Currently, common flame retardant ingredients mainly include inorganic flame retardants and organic flame retardants. Inorganic flame retardants mainly include hydroxide particles such as magnesium hydroxide particles and calcium hydroxide. The decomposition process of such substances at high temperatures absorbs part of the combustion heat to achieve the purpose of flame retardancy. However, in order to achieve a better flame retardant effect, a higher doping amount (20-40wt%) is required, which increases the density of the hydrophobic aerogel and also reduces its thermal insulation performance. The use of organic flame retardants mainly involves the use of hydrophobic modifiers containing complex aromatic groups to achieve a flame retardant effect. Although their decomposition requires the absorption of a large amount of heat, which can increase the ignition point to a certain extent, they cannot avoid thermal decomposition and combustion. In addition, the introduction of a large number of aromatic groups leads to the production of toxic and irritating gases during high-temperature decomposition, further increasing the potential combustion hazard. On the other hand, the introduction of organic or inorganic flame retardant components often requires doping / modification during the preparation process, and the mature preparation process of the aerogel material needs to be changed to adapt to the doping / modification process, which imposes many restrictions on the preparation process of aerogels and the preparation of composite materials. Summary of the Invention

[0003] In view of this, the main purpose of the present invention is to provide a flame-retardant hydrophobic aerogel material, its preparation method, and application. The problem to be solved is to prepare a magnesium oxide nanomasking layer on the surface of the aerogel nanoskeleton by atomic layer deposition, and further convert it into a magnesium carbonate dual-functional partial masking layer with flame retardant effect. Utilizing the difference in chemical properties between the functional partial masking layer and the partially exposed aerogel surface, the vacuum vapor modification process is used to promote the selective reaction of the modifier with the unmasked gel nanoparticle surface to graft hydrophobic groups. The amount of flammable hydrophobic groups introduced can be effectively controlled. While achieving a hydrophobic effect, the magnesium carbonate component of the masking layer provides flame retardant properties through the endothermic decomposition process at high temperature, thereby achieving both flame retardant and hydrophobic effects.

[0004] The purpose of the present invention and the technical problem solved are achieved by adopting the following technical solutions. The present invention proposes a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0005] 1) heat-treating the aerogel material to be processed;

[0006] 2) depositing a nano-oxide layer on the surface of the heat-treated aerogel material;

[0007] 3) converting the nano-oxide layer on the surface of the aerogel material into a partial masking layer;

[0008] 4) converting a partial masking layer on the surface of the aerogel material into a dual-functional partial masking layer;

[0009] 5) The aerogel material having the dual-functional partial masking layer is subjected to vacuum vapor modification, followed by post-treatment to obtain the flame-retardant hydrophobic aerogel material.

[0010] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0011] Preferably, in the method for preparing the flame retardant hydrophobic aerogel material, in step 1), the heat treatment comprises the following steps:

[0012] The aerogel material to be treated is heated to 350-400°C at a heating rate of 5-10°C / min and kept warm for 2-4 hours.

[0013] Preferably, in the aforementioned method for preparing the flame-retardant hydrophobic aerogel material, in step 2), the nano-oxide layer contains more than 90 wt % of magnesium oxide and has a thickness of 50-200 nm.

[0014] Preferably, in the method for preparing the flame retardant hydrophobic aerogel material, in step 2), the deposition is atomic layer deposition, with an organic metal precursor and an oxygen-containing precursor as the metal source and the oxygen source, respectively, and an inert gas as the carrier gas and the purge gas.

[0015] Preferably, in the aforementioned method for preparing a flame-retardant hydrophobic aerogel material, in step 2), the organometallic precursor is bis(ethylcyclopentadienylmagnesium) or bis(cyclopentadienylmagnesium); the oxygen-containing precursor is water or ozone; and the inert gas is argon or nitrogen.

[0016] Preferably, in the method for preparing the aforementioned flame retardant hydrophobic aerogel material, in step 2), the deposition temperature is 80-150°C; the deposition cycle includes six steps of organic metal precursor pulse, standing, inert gas purge, oxygen-containing precursor pulse, standing, and inert precursor purge, and the corresponding times are (2-10s)-(>80s)-(>150s)-(0.8-3s)-(>80s)-(>150s).

[0017] Preferably, in the aforementioned method for preparing the flame-retardant hydrophobic aerogel material, in step 2), the deposition cycle is 10-60.

[0018] Preferably, in the method for preparing the flame-retardant hydrophobic aerogel material, in step 3), the partial masking layer contains more than 90 wt % of magnesium oxide, which is obtained by sintering and converting the magnesium oxide nano-oxide layer obtained in step 2).

[0019] Preferably, in the aforementioned method for preparing the flame-retardant hydrophobic aerogel material, in step 3), the temperature of the conversion is 450-500° C., and the time is 0.5-1 h.

[0020] Preferably, in the method for preparing the flame-retardant hydrophobic aerogel material, in step 4), the dual-functional partial masking layer contains more than 90 wt % of magnesium carbonate; it is obtained by reacting the magnesium oxide partial masking layer obtained in step 3).

[0021] Preferably, in the aforementioned method for preparing the flame-retardant hydrophobic aerogel material, in step 4), the conversion pressure is 0.2-0.5 MPa and the conversion time is 2-4 hours.

[0022] Preferably, in the aforementioned method for preparing the flame retardant hydrophobic aerogel material, in step 5), the vacuum vapor modification step comprises:

[0023] The aerogel material with a dual-functional partial masking layer is modified in a vacuum gas phase by selectively modifying the hydrophobic group with a modifying agent under low pressure conditions; then an inert gas is introduced for purging.

[0024] Preferably, in the aforementioned method for preparing the flame-retardant hydrophobic aerogel material, in step 5), the amount of the modifier added is 1 / 30-1 / 10 of the mass of the aerogel material having the dual-functional partial masking layer.

[0025] Preferably, in the aforementioned method for preparing the flame-retardant hydrophobic aerogel material, in step 5), the low-pressure vacuum pressure is -0.07 MPa to -0.05 MPa, and the modification time is 2-6 hours.

[0026] Preferably, in the aforementioned method for preparing the flame-retardant hydrophobic aerogel material, in step 5), the purge time is more than 5 minutes.

[0027] Preferably, in the aforementioned method for preparing the flame-retardant hydrophobic aerogel material, in step 5), the post-treatment temperature is 150-250° C. and the time is greater than 1 hour.

[0028] The objectives of the present invention and the technical problems solved therein are achieved by the following technical solutions: The present invention provides a flame-retardant, hydrophobic aerogel material having a contact angle greater than 120°, a calorific value of combustion less than 6 MJ / kg, and no noticeable flame or smoke at temperatures greater than 600°C; the flame-retardant, hydrophobic aerogel material is produced by the above-described method.

[0029] The objectives of the present invention and the technical problems solved therein are achieved by the following technical solutions: The present invention provides a thermal insulation material comprising a flame-retardant hydrophobic aerogel material having a contact angle greater than 120°, a calorific value of combustion less than 6 MJ / kg, and no noticeable flame or smoke at temperatures greater than 600°C.

[0030] By means of the above technical solution, the flame-retardant hydrophobic aerogel material provided by the present invention and its preparation method and application have at least the following advantages:

[0031] The present invention sequentially uses atomic layer deposition of a nano-oxide layer on the surface of an aerogel nanoparticle skeleton, thermally converts it into a partial masking layer, and then uses a gas phase reaction to form a dual-functional partial masking layer with a flame retardant effect. Subsequently, selective grafted hydrophobic groups are modified with the help of vacuum gas phase to achieve a controllable modification process on the surface of the aerogel material nanoparticle. Not only can the dual-functional partial masking layer with flame retardant properties be introduced, but also selective grafting of hydrophobic groups can be completed in the vacant areas of the dual-functional partial masking layer, effectively controlling the content of the hydrophobic organic group, effectively reducing the content of the combustible component while achieving the hydrophobic effect, and combining the flame retardant effect of the dual-functional partial masking layer to effectively improve the flame retardant effect of the hydrophobic aerogel.

[0032] The present invention prepares a nano-oxide layer on the outer surface of aerogel nanoparticles and converts it into a partial masking layer (magnesium carbonate) that simultaneously has a flame retardant effect and blocks surface hydroxyl groups. This dual-functional partial masking layer can decompose at high temperatures, absorbing heat and releasing carbon dioxide to achieve a flame retardant effect. Furthermore, since the dual-functional masking layer is composed of magnesium carbonate, the surface hydroxyl content is relatively low, which is not conducive to the reaction of organic hydrophobic modifiers. Therefore, during the subsequent modification process, the modifier tends to react with the aerogel surface hydroxyl groups not covered by the dual-functional partial masking layer, achieving selective grafting of hydrophobic groups. This controls the amount of hydrophobic organic groups introduced and reduces the total content of combustibles.

[0033] The present invention uses an oxide layer prepared by atomic layer deposition and ultimately converted into a dual-function partial shielding layer. The overall content of the introduced inorganic flame retardant component is low and distributed only on the outer surface of the aerogel nanoparticle skeleton, avoiding the introduction of excessive flame retardants and reducing the impact on the density and thermal insulation properties of the aerogel composite material. At the same time, because the flame retardant effect of the flame retardant component mainly depends on the controlled grafting of organic hydrophobic groups and the release of endothermic carbon dioxide products from the decomposition of the dual-function shielding layer, the use of flame retardant hydrophobic agents containing aromatic groups is avoided, which emit a pungent odor when exposed to high temperatures or open flames, reducing potential hazards. Vapor-phase surface modification is performed using vacuum vapor modification. The low-pressure vapor modification process can promote the vaporization and diffusion of high-boiling point modifiers into the interior of the aerogel pores, thereby reacting with the partially exposed hydroxyl groups on the surface of the aerogel nanoparticles to achieve a vapor-phase reaction process. Compared with the atmospheric pressure vapor modification process, the low-pressure environment reduces the collision of other gas molecules with organic modifier molecules, which facilitates the diffusion of modifier molecules into the internal pores of the aerogel, significantly reducing the amount of modifier used and improving the reaction efficiency. Due to the lower amount of modifier, the amount of flammable hydrophobic groups introduced onto the surface of aerogel nanoparticles can also be further controlled.

[0034] In addition, each step included in the present invention is a post-modification process, which can directly introduce flame retardant components and hydrophobic groups into aerogel materials prepared by various existing "sol-gel" processes in a controllable manner, without affecting the mature preparation process of existing aerogel materials, thereby expanding the scope of application.

[0035] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Flowchart showing the preparation process of flame retardant hydrophobic aerogel materials according to some embodiments of the present invention;

[0037] Figure 2 Schematic diagram of the surface modification process of nanoparticles of flame-retardant hydrophobic aerogel materials according to some embodiments of the present invention;

[0038] 1-aerogel nanoparticle skeleton; 2-oxide masking layer; 3-oxide partial masking layer; 4-dual-functional partial masking layer; 5-hydrophobic group;

[0039] Figure 3 These are photos of flame-retardant hydrophobic aerogel materials according to some embodiments of the present invention.

[0040] Figure 4 Schematic diagram of the connection of the vacuum gas phase modification device of the present invention;

[0041] 10-pressure vessel; 20-buffer chamber; 30-valve; 40-inert gas cylinder; 50-exhaust gas treatment device; 60-bracket; 70-vacuum pump; 80-carbon dioxide cylinder. DETAILED DESCRIPTION

[0042] To further illustrate the technical means and effectiveness of the present invention in achieving its intended objectives, the following, in conjunction with preferred embodiments, describes in detail a flame-retardant, hydrophobic aerogel material, its preparation method, and its specific embodiments, structures, features, and effectiveness. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0043] The following materials or reagents, unless otherwise specified, were commercially available.

[0044] like Figure 1 As shown, some embodiments of the present invention provide a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0045] S1 heat treatment

[0046] The aerogel material to be treated is placed in a muffle furnace and heated to 350-400°C at a heating rate of 5-10°C / min. The temperature is then maintained for 2-4 hours to burn out the unreacted organic groups in the aerogel. If the temperature is too low (<350°C) or the treatment time is too short (<2 hours), the residual combustible organic matter cannot be completely burned out. If the temperature is too high (>400°C) or the treatment time is too long (>4 hours), the aerogel nanoparticles may be over-sintered.

[0047] S2 Preparation of Nano-Oxide Layer

[0048] S21 places the heat-treated aerogel material into the atomic layer deposition equipment (ALD) chamber, with an organic metal precursor (which can be one of bis(ethylcyclopentadienylmagnesium or bis(cyclopentadienylmagnesium)) and an oxygen-containing precursor (which can be water or ozone) as the metal source and oxygen source, respectively. Set the chamber temperature to 150-250°C, heat the organic metal precursor to 80-150°C, and use an inert gas (argon or nitrogen) as the carrier gas and purge gas. If the chamber temperature is too low (<150°C) or the metal precursor temperature is too low (<80°C), the activity of the gaseous reactants will be affected; if the chamber temperature is too high (>250°C) or the metal precursor temperature is too high (>150°C), the reactants will easily decompose.

[0049] S22 includes six steps in one deposition cycle: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of (2-10s)-(>80s)-(>150s)-(0.8-3s)-(>80s)-(>150s). If the organometallic precursor pulse time is too short (<2s) or the oxygen-containing precursor pulse time is too short (<0.8s), it will not be possible to introduce enough reactants to form a nano-oxide layer; if the time is too long (>10s), it will easily cause the aerogel to adsorb too many reactants, affecting the next cycle reaction process. If the rest time is too short (<80s), it will easily lead to incomplete reaction, and if the inert precursor purge time is too short (<150s), it will easily lead to incomplete initial blowing of reaction residues, affecting subsequent reactions.

[0050] S23 deposits for 30-120 cycles, forming a nano-oxide layer (primarily composed of magnesium oxide, with a content of greater than 90 wt%) with a thickness of approximately 50-200 nm on the surface of the aerogel nanoparticle skeleton. Too few deposition cycles (<30 cycles) will not form a complete oxide masking layer. Too many deposition cycles (>120 cycles) will result in an excessively thick oxide masking layer, making it difficult to sinter and destroy it during heat treatment, resulting in a partial masking layer.

[0051] S3 converts the nano-oxide layer into a partial masking layer

[0052] The aerogel material with the nano-oxide layer deposited is placed in a muffle furnace at 450-500°C and taken out after calcination for 0.5-1h to promote the sintering of the nano-oxide layer and convert it into a rough nano-particle layer, exposing part of the aerogel skeleton surface, so that the originally uniform oxide layer becomes a partial masking layer (containing more than 90wt% magnesium oxide). If the calcination temperature is too low (<450°C) or the calcination time is too short (<0.5h), it will not be able to effectively promote the sintering and destruction of the nano-oxide layer itself, and it will be difficult to expose part of the aerogel skeleton surface to form a partial masking layer. If the calcination temperature is too high (>500°C) or the calcination time is too long (>1h), it is easy to cause severe sintering of the aerogel nano-skeleton and destroy the aerogel nanostructure.

[0053] S4 mask converted to dual-function partial mask

[0054] S41: Place the aerogel material with a masking layer into a pressure vessel, fill it with carbon dioxide to make the pressure in the container reach 0.2-0.5MPa, and maintain the pressure for more than 4 hours. The masking layer with magnesium oxide as the main body is converted into an effective masking layer with magnesium carbonate as the main body (content is more than 90wt%), then reduce the pressure to normal pressure and take out the aerogel material. When the pressure is too low (<0.2MPa) or the holding time is too short (<4h), it is impossible to ensure that the main component of the masking layer, magnesium oxide, reacts fully with carbon dioxide gas to form magnesium carbonate. When the pressure is too high (>0.5MPa), it is not conducive to the rapid discharge of carbon dioxide after the reaction is completed.

[0055] S5 Vacuum Vapor Modification

[0056] S51: placing the aerogel material with the dual-functional masking layer into the pressure vessel 10, and further connecting the pressure vessel to the vacuum pump 70, the small-sized buffer chamber 20 and the tail gas treatment device 50 containing activated carbon via a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0057] A modifier can be placed in the S52 buffer chamber, and the amount of the modifier mixture added is 1 / 30-1 / 10 of the mass of the aerogel material being processed. When the amount of modifier is too low (such as less than 1 / 30 of the material mass), it is easy to fail to introduce enough hydrophobic groups, resulting in poor hydrophobicity. When the amount of modifier is too high (such as greater than 1 / 10 of the material mass), the excess modifier is difficult to remove by inert gas purging, affecting the subsequent treatment process.

[0058] S54: The buffer chamber 20 is purged and filled with inert gas. After the vacuum pump 70 evacuates the pressure vessel 10 to a pressure between -0.09 MPa and -0.08 MPa, the gas outlet valve is closed and the valve between the buffer chamber 20 and the pressure vessel 10 is subsequently opened. The modifier will vaporize and enter the pressure vessel along with a small amount of inert gas. The interior of the vessel will perform gas-phase modification on the aerogel or composite material under low pressure. During the gas-phase modification process, the pressure in the pressure vessel is maintained at -0.07 MPa to -0.05 MPa, and the modification time is 2-6 hours. When the vacuum pump's exhaust pressure is insufficient (>-0.08 MPa), the equilibrium pressure after opening the valve of the buffer chamber 20 will be too high (>-0.05 MPa). At this time, the vacuum degree is insufficient to promote the vaporization of the modifier, and a large number of gas molecules still exist to hinder the rapid diffusion of the modifier molecules. When the vacuum pump's exhaust pressure is too low (>-0.09 MPa), an excessively long exhaust time is required, which is not conducive to the rapid reaction between the modifier and the aerogel. When the modification time is too short (<2h), the modifier is not able to penetrate the interior of the aerogel nanoskeleton to complete the modification process, resulting in insufficient hydrophobicity. When the modification time is too long (>6h), the modifier is likely to introduce too many hydrophobic groups, resulting in an excessively high combustible content and an increased calorific value.

[0059] After the modification is completed in step S55, pure nitrogen (99.99% purity) is introduced into the pressure vessel 10. After reaching atmospheric pressure, the valve between the pressure vessel 10 and the tail gas treatment device 50 is opened, and the gas is discharged through the tail gas treatment device 50. The purge time is greater than 5 minutes. If the purge time is less than 5 minutes, it is insufficient to completely remove the remaining modification agent and reaction byproducts.

[0060] S6 post-processing

[0061] The modified aerogel material is removed and placed in a hot air oven at 150-250°C for more than 1 hour to remove excess modifiers, resulting in a flame-retardant, hydrophobic aerogel material. If the temperature is too low (<150°C) or the time is too short (<1 hour), the removal of the modifier from the aerogel cannot be promoted. If the temperature is too high (>250°C), the modified hydrophobic groups will decompose, reducing the hydrophobic effect.

[0062] Some embodiments of the present invention further provide a flame retardant hydrophobic aerogel material, wherein the contact angle of the flame retardant hydrophobic aerogel material is greater than 120°, the calorific value of combustion is less than 6MJ / kg, and there is no obvious flame and smoke at a temperature greater than 600°C; the flame retardant hydrophobic aerogel material is Figure 1 The method shown in the figure is to obtain an oxide masking layer 2 by atomic deposition on the surface of the aerogel nanoparticle skeleton 1 to be treated, and then obtain an oxide partial masking layer 3 by heat treatment, and then convert it into a dual-functional partial masking layer 4 with magnesium carbonate as the main body by gas phase reaction, and finally graft hydrophobic groups 5 ( Figure 2 ); The obtained flame retardant hydrophobic aerogel material exhibits typical hydrophobic properties (such as Figure 3 shown).

[0063] Some embodiments of the present invention also provide a thermal insulation material, which can adopt the above-mentioned flame retardant hydrophobic aerogel material. The flame retardant hydrophobic aerogel material has a contact angle greater than 120°, a combustion calorific value less than 6MJ / kg, and no obvious flame and smoke at a temperature greater than 600°C.

[0064] The specific implementation methods of the present invention are further described in detail below in conjunction with the examples, but they should not be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by technicians in this field based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0065] Unless otherwise specified, the materials and reagents mentioned below are commercially available products familiar to those skilled in the art. Unless otherwise specified, the methods described are all well-known methods in the art. Unless otherwise defined, technical or scientific terms used shall have the same meanings as those commonly understood by those skilled in the art.

[0066] Example 1

[0067] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0068] (1) The glass fiber reinforced silica aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 22.7 g, thermal conductivity at 300 ° C is 0.0323 W / (m·K) -1 ) is placed in a muffle furnace, heated to 350°C, with a heating rate of 5°C / min, and kept warm for 2 hours; the glass fiber reinforced silica aerogel material is prepared by an existing method, and its preparation steps include: mixing tetraethyl orthosilicate (TEOS), anhydrous ethanol and water in a molar ratio of 1:8:6, and stirring for 10 minutes; then adding 1 mol / L nitric acid solution to adjust the pH value to 3, stirring at room temperature for 4 hours, and then adding 1 mol / L ammonia water to adjust the pH value to 8 to obtain silica sol; preparing a silica sol with a density of 0.08 g / cm 3 A glass fiber mat was impregnated with the silica sol and placed in a mold. After gelation, the mold was sealed and aged at 60°C for three days. After aging, the gel was removed and soaked in anhydrous ethanol for 8 hours to displace the solvent, repeating this process three times. After drying using a supercritical carbon dioxide drying apparatus, a glass fiber-reinforced silica aerogel material was obtained. This material served as the aerogel material to be treated in Example 1.

[0069] (2) The heat-treated glass fiber-reinforced silica aerogel material was placed in the atomic layer deposition (ALD) chamber, with bis(ethylcyclopentadienyl) magnesium (Mg(CpEt)2) serving as the metal source and ultrapure water as the oxygen source, respectively. The chamber temperature was set at 200°C, the bis(ethylcyclopentadienyl) magnesium was heated to 80°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0070] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 4s-100s-180s-0.8s-100s-180s.

[0071] (4) After 50 cycles of deposition, a nano-oxide layer with a thickness of about 80 nm (its main component is magnesium oxide with a content of about 95 wt%) is prepared on the surface of the aerogel nanoparticle skeleton.

[0072] (5) The silica aerogel with the nano-magnesium oxide layer deposited was placed in a muffle furnace at 500°C, calcined for 0.5 h, taken out, and cooled to room temperature to obtain a glass fiber reinforced silica aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 95 wt%).

[0073] (6) The glass fiber reinforced silica aerogel with a partial masking layer is placed in a pressure vessel 10, which is connected to a gas cylinder, an exhaust valve, a vacuum pump 70 and a buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 10) via a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0074] (7) Fill the pressure vessel 10 of step (6) with carbon dioxide until the pressure inside the vessel reaches 0.5 MPa, and maintain the pressure for 4 hours to promote the reaction between the main component of the partial masking layer and the carbon dioxide to obtain a dual-function partial masking layer (the main component of which is magnesium carbonate, with a content of about 95wt%).

[0075] (8) Open the drain valve of the pressure vessel 10, drain the interior to restore normal pressure, and then close the valve. Simultaneously, close the valve between the pressure vessel 10 and the buffer chamber 20, and place 1.2 g of trimethylchlorosilane into the open container in the buffer chamber 20.

[0076] (9) The buffer chamber 20 is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0077] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.09 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.07 MPa, and the modification time is 5 hours.

[0078] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through the tail gas treatment device 50 containing activated carbon. The purge time is 5 minutes; the tail gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0079] (12) The modified glass fiber reinforced silica aerogel composite material block was taken out and placed in a hot air oven at 180°C for 1 hour to remove excess modifiers to obtain a glass fiber reinforced silica aerogel material.

[0080] The mass of the glass fiber reinforced silica aerogel obtained in this example is 23.6 g, and the thermal conductivity at 300°C is 0.0341 W / (m·K). -1 The contact angle is 124.7°, it is hydrophobic, the calorific value of combustion is 5.77MJ / kg, and there is no obvious flame or smoke in a high temperature environment (600℃).

[0081] Example 2

[0082] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0083] (1) The glass fiber reinforced silica aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 22.7 g, thermal conductivity at 300 ° C is 0.0323 W / (m·K) -1) is placed in a muffle furnace, heated to 350°C, with a heating rate of 5°C / min, and kept warm for 2 hours; the glass fiber reinforced silica aerogel material is prepared by an existing method, and its preparation steps include: mixing tetraethyl orthosilicate (TEOS), anhydrous ethanol and water in a molar ratio of 1:8:6, and stirring for 10 minutes; then adding 1 mol / L nitric acid solution to adjust the pH value to 3, stirring at room temperature for 4 hours, and then adding 1 mol / L ammonia water to adjust the pH value to 8 to obtain silica sol; preparing a silica sol with a density of 0.08 g / cm 3 A glass fiber mat was impregnated with the silica sol and placed in a mold. After gelation, the mold was sealed and aged at 60°C for three days. After aging, the gel was removed and soaked in anhydrous ethanol for 8 hours to displace the solvent, repeating this process three times. After drying using a supercritical carbon dioxide drying apparatus, a glass fiber-reinforced silica aerogel material was obtained. This material served as the aerogel material to be treated in Example 2.

[0084] (2) The heat-treated glass fiber-reinforced silica aerogel material was placed in the atomic layer deposition (ALD) chamber, with bis(ethylcyclopentadienyl) magnesium (Mg(CpEt)2) serving as the metal source and ultrapure water as the oxygen source, respectively. The chamber temperature was set at 180°C, the bis(ethylcyclopentadienyl) magnesium was heated to 100°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0085] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 3.5s-100s-180s-1.2s-100s-180s.

[0086] (4) Deposition was performed for 60 cycles to prepare a nano-oxide layer with a thickness of about 100 nm (its main component was magnesium oxide with a content of about 96 wt%) on the surface of the aerogel nanoparticle skeleton.

[0087] (5) The silica aerogel with the nano-magnesium oxide layer deposited was placed in a muffle furnace at 500°C, calcined for 0.5 h, taken out, and cooled to room temperature to obtain a glass fiber reinforced silica aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 96 wt%).

[0088] (6) The glass fiber reinforced silica aerogel with a partial masking layer is placed in a pressure vessel 10, which is connected to a gas cylinder, an exhaust valve, a vacuum pump 70 and a buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 10) via a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0089] (7) Carbon dioxide is injected into the pressure vessel 10 of step (6) to make the pressure inside the vessel reach 0.5 MPa, and the pressure is maintained for 4 hours to promote the reaction between the main component of the partial masking layer and the carbon dioxide to obtain a dual-function partial masking layer (the main component of which is magnesium carbonate, with a content of about 96 wt%).

[0090] (8) Open the drain valve of the pressure vessel 10, drain the interior to restore normal pressure, and then close the valve. Simultaneously, close the valve between the pressure vessel 10 and the buffer chamber 20, and place 1.2 g of trimethylchlorosilane into the open container in the buffer chamber.

[0091] (9) The buffer chamber 20 is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0092] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.09 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.07 MPa, and the modification time is 5 hours.

[0093] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through an exhaust gas treatment device containing activated carbon. The purge time is 5 minutes; the exhaust gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0094] (12) The modified glass fiber reinforced silica aerogel composite material block was taken out and placed in a hot air oven at 180°C for 1 hour to remove excess modifiers to obtain a glass fiber reinforced silica aerogel material.

[0095] The glass fiber reinforced silica aerogel obtained in this example has a mass of 23.9 g, a thermal conductivity of 0.0347 W / (m·K) at 300° C., a contact angle of 128.4°, is hydrophobic, and has a calorific value of 5.81 MJ / kg. No obvious flame or smoke is produced in a high temperature environment (600° C.).

[0096] Example 3

[0097] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0098] (1) The glass fiber reinforced silica aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 22.7 g, thermal conductivity at 300 ° C is 0.0323 W / (m·K) -1 ) is placed in a muffle furnace, heated to 350°C, with a heating rate of 5°C / min, and kept warm for 2 hours; the glass fiber reinforced silica aerogel material is prepared by an existing method, and its preparation steps include: mixing tetraethyl orthosilicate (TEOS), anhydrous ethanol and water in a molar ratio of 1:8:6, and stirring for 10 minutes; then adding 1 mol / L nitric acid solution to adjust the pH value to 3, stirring at room temperature for 4 hours, and then adding 1 mol / L ammonia water to adjust the pH value to 8 to obtain silica sol; preparing a silica sol with a density of 0.08 g / cm 3 A glass fiber mat was impregnated with the silica sol and placed in a mold. After gelation, the mold was sealed and aged at 60°C for three days. After aging, the gel was removed and soaked in anhydrous ethanol for 8 hours to displace the solvent, repeating this process three times. After drying using a supercritical carbon dioxide drying apparatus, a glass fiber-reinforced silica aerogel material was obtained. This material served as the aerogel material to be treated in Example 3.

[0099] (2) The heat-treated glass fiber-reinforced silica aerogel material was placed in an atomic layer deposition (ALD) chamber, with biscyclopentadienyl magnesium (Mg(Cp)2) as the metal source and ozone as the oxygen source, respectively. The chamber temperature was set at 220°C, the biscyclopentadienyl magnesium was heated to 110°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0100] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 5.5s-120s-240s-1.8s-120s-240s.

[0101] (4) After 70 cycles of deposition, a nano-oxide layer with a thickness of about 120 nm (its main component is magnesium oxide with a content of about 97 wt%) is prepared on the surface of the aerogel nanoparticle skeleton.

[0102] (5) The silica aerogel with the nano-magnesium oxide layer deposited was placed in a muffle furnace at 500°C, calcined for 0.5 h, taken out, and cooled to room temperature to obtain a glass fiber reinforced silica aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 97 wt%).

[0103] (6) The glass fiber reinforced silica aerogel with a partial masking layer is placed in a pressure vessel 10, which is connected to a gas cylinder, an exhaust valve, a vacuum pump 70 and a buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 10) via a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0104] (7) Carbon dioxide is injected into the pressure vessel 10 of step (6) to make the pressure inside the vessel reach 0.5 MPa, and the pressure is maintained for 4 hours to promote the reaction between the main component of the partial masking layer and the carbon dioxide to obtain a dual-function partial masking layer (whose main component is magnesium carbonate, with a content of about 97 wt%).

[0105] (8) Open the drain valve of the pressure vessel 10 to drain the interior and restore the pressure to normal, then close the valve. Simultaneously, close the valve between the pressure vessel 10 and the buffer chamber 20, and place 1.2 g of trimethylchlorosilane into the open container in the buffer chamber.

[0106] (9) The buffer chamber is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0107] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.09 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.07 MPa, and the modification time is 5 hours.

[0108] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through the tail gas treatment device 50 containing activated carbon. The purge time is 5 minutes; the tail gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0109] (12) The modified glass fiber reinforced silica aerogel composite material block was taken out and placed in a hot air oven at 180°C for 1 hour to remove excess modifiers to obtain a glass fiber reinforced silica aerogel material.

[0110] The mass of the glass fiber reinforced silica aerogel obtained in Example 3 was 24.2 g, and the thermal conductivity at 300°C was 0.0346 W / (m·K). -1 The contact angle is 122.3°, it is hydrophobic, the calorific value of combustion is 5.14MJ / kg, and there is no obvious flame or smoke in a high temperature environment (600℃).

[0111] Example 4

[0112] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0113] (1) The glass fiber reinforced silica aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 22.7 g, thermal conductivity at 300 ° C is 0.0323 W / (m·K) -1 ) is placed in a muffle furnace, heated to 350°C, with a heating rate of 5°C / min, and kept warm for 2 hours; the glass fiber reinforced silica aerogel material is prepared by an existing method, and its preparation steps include: mixing tetraethyl orthosilicate (TEOS), anhydrous ethanol and water in a molar ratio of 1:8:6, and stirring for 10 minutes; then adding 1 mol / L nitric acid solution to adjust the pH value to 3, stirring at room temperature for 4 hours, and then adding 1 mol / L ammonia water to adjust the pH value to 8 to obtain silica sol; preparing a silica sol with a density of 0.08 g / cm 3 A glass fiber mat was impregnated with the silica sol and placed in a mold. After gelation, the mold was sealed and aged at 60°C for three days. After aging, the gel was removed and soaked in anhydrous ethanol for 8 hours to displace the solvent, repeating this process three times. After drying using a supercritical carbon dioxide drying apparatus, a glass fiber-reinforced silica aerogel material was obtained. This material served as the aerogel material to be treated in Example 4.

[0114] (2) The heat-treated glass fiber-reinforced silica aerogel material was placed in the atomic layer deposition (ALD) chamber, with bis(ethylcyclopentadienyl) magnesium (Mg(CpEt)2) serving as the metal source and ultrapure water as the oxygen source, respectively. The chamber temperature was set at 200°C, the bis(ethylcyclopentadienyl) magnesium was heated to 80°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0115] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 4s-100s-180s-0.8s-100s-180s.

[0116] (4) After 50 cycles of deposition, a nano-oxide layer with a thickness of about 80 nm (its main component is magnesium oxide with a content of about 94 wt%) is prepared on the surface of the aerogel nanoparticle skeleton.

[0117] (5) The silica aerogel with the nano-magnesium oxide layer deposited was placed in a muffle furnace at 450°C, calcined for 0.5 h, taken out, and cooled to room temperature to obtain a glass fiber reinforced silica aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 94 wt%).

[0118] (6) The glass fiber reinforced silica aerogel with a partial masking layer is placed in a pressure vessel. The pressure vessel 10 is connected to the gas cylinder, the emptying valve, the vacuum pump 70 and the buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 10) via a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0119] (7) Filling the pressure vessel of step (6) with carbon dioxide until the pressure inside the vessel reaches 0.3 MPa, and maintaining the pressure for 5 hours, thereby causing the main component of the partial masking layer to react with the carbon dioxide to obtain a dual-function partial masking layer (whose main component is magnesium carbonate, with a content of about 94 wt%).

[0120] (8) Open the drain valve of the pressure vessel, drain the interior and restore the pressure to normal, then close the valve. At the same time, close the valve between the pressure vessel and the buffer chamber, and place 1.16 g of dichlorodimethylsilane into the open container in the buffer chamber.

[0121] (9) The buffer chamber is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0122] (10) Use a vacuum pump to evacuate the pressure vessel to approximately -0.09 MPa, close the air inlet valve, and then open the valve between the buffer chamber and the pressure vessel. Maintain the pressure in the pressure vessel at approximately -0.07 MPa. The modification time is 5 h.

[0123] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel. After reaching normal pressure, the gas is discharged through an exhaust gas treatment device containing activated carbon. The purge time is 5 minutes; the exhaust gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0124] (12) The modified glass fiber reinforced silica aerogel composite material block was taken out and placed in a hot air oven at 180°C for 1 hour to remove excess modifiers to obtain a glass fiber reinforced silica aerogel material.

[0125] The mass of the glass fiber reinforced silica aerogel obtained in Example 4 was 23.5 g, and the thermal conductivity at 300°C was 0.0338 W / (m·K). -1 The contact angle is 118.4°, it is hydrophobic, the calorific value of combustion is 5.08MJ / kg, and there is no obvious flame or smoke in a high temperature environment (600℃).

[0126] Example 5

[0127] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0128] (1) The glass fiber reinforced silica aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 22.7 g, thermal conductivity at 300 ° C is 0.0323 W / (m·K) -1) is placed in a muffle furnace, heated to 350°C, with a heating rate of 5°C / min, and kept warm for 2 hours; the glass fiber reinforced silica aerogel material is prepared by an existing method, and its preparation steps include: mixing tetraethyl orthosilicate (TEOS), anhydrous ethanol and water in a molar ratio of 1:8:6, and stirring for 10 minutes; then adding 1 mol / L nitric acid solution to adjust the pH to 3, stirring at room temperature for 4 hours, and then adding 1 mol / L ammonia water to adjust the pH to 8 to obtain silica sol; preparing a silica sol with a density of 0.08 g / cm 3 A glass fiber mat was impregnated with the silica sol and placed in a mold. After gelation, the mold was sealed and aged at 60°C for three days. After aging, the gel was removed and soaked in anhydrous ethanol for 8 hours to displace the solvent, repeating this process three times. After drying using a supercritical carbon dioxide drying apparatus, a glass fiber-reinforced silica aerogel material was obtained. This material served as the aerogel material to be treated in Example 5.

[0129] (2) The heat-treated glass fiber-reinforced silica aerogel material was placed in the atomic layer deposition (ALD) chamber, with bis(ethylcyclopentadienyl) magnesium (Mg(CpEt)2) serving as the metal source and ultrapure water as the oxygen source, respectively. The chamber temperature was set at 200°C, the bis(ethylcyclopentadienyl) magnesium was heated to 80°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0130] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 4s-100s-180s-0.8s-100s-180s.

[0131] (4) After 50 cycles of deposition, a nano-oxide layer with a thickness of about 80 nm (its main component is magnesium oxide with a content of about 93 wt%) is prepared on the surface of the aerogel nanoparticle skeleton.

[0132] (5) The silica aerogel with the nano-magnesium oxide layer deposited was placed in a muffle furnace at 500°C, calcined for 0.5 h, taken out, and cooled to room temperature to obtain a glass fiber reinforced silica aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 93 wt%).

[0133] (6) The glass fiber reinforced silica aerogel with a partial masking layer is placed in a pressure vessel 10, which is connected to a gas cylinder, an exhaust valve, a vacuum pump 70 and a buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 20) via a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0134] (7) Carbon dioxide is injected into the pressure vessel 10 of step (6) to make the pressure inside the vessel reach 0.5 MPa, and the pressure is maintained for 4 hours to promote the reaction between the main component of the partial masking layer and the carbon dioxide to obtain a dual-function partial masking layer (the main component of which is magnesium carbonate, with a content of about 93wt%).

[0135] (8) Open the drain valve of the pressure vessel 10, drain the interior to restore normal pressure, and then close the valve. Simultaneously, close the valve between the pressure vessel 10 and the buffer chamber 20, and place 1.36 g of dimethyldichlorosilane into the open container in the buffer chamber.

[0136] (9) The buffer chamber 20 is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0137] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.08 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.06 MPa, and the modification time is 6 hours.

[0138] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through the tail gas treatment device 50 containing activated carbon. The purge time is 10 minutes; the tail gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0139] (12) The modified glass fiber reinforced silica aerogel composite material block was taken out and placed in a hot air oven at 150°C for 2 hours to remove excess modifiers to obtain a glass fiber reinforced silica aerogel material.

[0140] The glass fiber reinforced silica aerogel obtained in this example has a mass of 23.3 g, a thermal conductivity of 0.0343 W / (m·K) at 300° C., a contact angle of 126.9°, is hydrophobic, and has a calorific value of 5.48 MJ / kg. No obvious flame or smoke is produced in a high temperature environment (600° C.).

[0141] Example 6

[0142] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0143] (1) The aluminum silicate fiber reinforced silica aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 19.8 g, thermal conductivity at 300 ° C is 0.0316 W / (m·K) -1 ) is placed in a muffle furnace, heated to 350°C, with a heating rate of 5°C / min, and kept warm for 2 hours; the aluminum silicate fiber reinforced silica aerogel material is prepared by an existing method, and its preparation steps include: mixing tetraethyl orthosilicate (TEOS), anhydrous ethanol and water in a molar ratio of 1:8:6, and stirring for 10 minutes; then adding 1 mol / L nitric acid to adjust the pH value to 3, stirring at room temperature for 4 hours, and then adding 1 mol / L ammonia water to adjust the pH value to 8 to obtain silica sol; preparing a silica sol with a density of 0.07 g / cm 3 The aluminum silicate fiber felt was impregnated with the silica sol and placed in a mold. After gelation, the mold was sealed and aged at 60°C for three days. After aging, the gel was removed and soaked in ethanol for 8 hours to displace the solvent, and this process was repeated three times. After drying using a supercritical carbon dioxide drying apparatus, an aluminum silicate fiber-reinforced silica aerogel material was obtained. This material served as the aerogel material to be treated in Example 6.

[0144] (2) The heat-treated aluminum silicate fiber-reinforced silica aerogel material was placed in an atomic layer deposition (ALD) chamber. Mg(CpEt)2 and ultrapure water served as the metal source and oxygen source, respectively. The chamber temperature was set at 200°C, Mg(CpEt)2 was heated to 80°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0145] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 4s-100s-180s-0.8s-100s-180s.

[0146] (4) Deposition for 60 cycles to prepare a nano-oxide layer with a thickness of about 100 nm (its main component is magnesium oxide, with a content of about 92 wt%) on the surface of the aerogel nanoparticle skeleton

[0147] (5) The silica aerogel after the nano-magnesium oxide layer deposition was placed in a muffle furnace at 500°C, calcined for 0.5 h, and then taken out and cooled to room temperature to obtain an aluminum silicate fiber reinforced silica aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 92 wt%).

[0148] (6) The aluminum silicate fiber reinforced silica aerogel with a partial masking layer is placed in a pressure vessel 10, and the pressure vessel 10 is connected to the gas cylinder, the emptying valve, the vacuum pump 70 and the buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 20) through a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0149] (7) Carbon dioxide is injected into the pressure vessel 10 of step (6) to make the pressure inside the vessel reach 0.5 MPa, and the pressure is maintained for 4 hours to promote the reaction between the main component of the partial masking layer and the carbon dioxide to obtain a dual-function partial masking layer (whose main component is magnesium carbonate, with a content of about 92 wt%).

[0150] (8) Open the drain valve of the pressure vessel 10 to drain the interior and restore the pressure to normal, then close the valve. Simultaneously, close the valve between the pressure vessel 10 and the buffer chamber 20 and place 1.05 g of trimethylchlorosilane into the open container in the buffer chamber 20.

[0151] (9) The buffer chamber 20 is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0152] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.08 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.06 MPa, and the modification time is 5 hours.

[0153] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through the tail gas treatment device 50 containing activated carbon. The purge time is 5 minutes; the tail gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0154] (12) The modified aluminum silicate fiber reinforced silica aerogel composite material block was taken out, placed in a hot air oven at 180°C, and baked for 1 hour to remove excess modifier to obtain an aluminum silicate fiber reinforced silica aerogel material.

[0155] The mass of the aluminum silicate fiber reinforced silica aerogel obtained in this example is 22.9 g, and the thermal conductivity is 0.337 W / (m·K) at 300°C. -1 The contact angle is 119.6°, it is hydrophobic, the calorific value of combustion is 5.31MJ / kg, and there is no obvious flame or smoke in a high temperature environment (600℃).

[0156] Example 7

[0157] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0158] (1) The high silica fiber reinforced silica aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 20.2 g, thermal conductivity at 300 ° C is 0.0341 W / (m·K) -1 ) is placed in a muffle furnace, heated to 350°C, with a heating rate of 5°C / min, and kept warm for 2 hours; the high-silica fiber reinforced silica aerogel material is prepared by an existing method, and its preparation steps include: mixing tetraethyl orthosilicate (TEOS), anhydrous ethanol and water in a molar ratio of 1:8:6, and stirring for 10 minutes; then adding 1 mol / L nitric acid solution to adjust the pH value to 3, stirring at room temperature for 4 hours, and then adding 1 mol / L ammonia water to adjust the pH value to 8 to obtain silica sol; preparing a silica sol with a density of 0.075 g / cm 3 A high-silica fiber felt was impregnated with the silica sol and placed in a mold. After gelation, the mold was sealed and aged at 60°C for three days. After aging, the gel was removed and soaked in anhydrous ethanol for 8 hours to displace the solvent, repeating this process three times. After drying using a supercritical carbon dioxide drying apparatus, a high-silica fiber-reinforced silica aerogel material was obtained. This material served as the aerogel material to be treated in Example 7.

[0159] (2) The heat-treated high-silica fiber-reinforced silica aerogel material was placed in an atomic layer deposition (ALD) chamber, with biscyclopentadienyl magnesium (Mg(Cp)2) as the metal source and ozone as the oxygen source, respectively. The chamber temperature was set to 210°C, the biscyclopentadienyl magnesium was heated to 100°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0160] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 3.5s-120s-180s-1s-120s-180s.

[0161] (4) After 50 cycles of deposition, a nano-oxide layer with a thickness of about 80 nm (its main component is magnesium oxide with a content of about 95 wt%) is prepared on the surface of the aerogel nanoparticle skeleton.

[0162] (5) The silica aerogel with the nano-magnesium oxide layer deposited was placed in a muffle furnace at 500°C, calcined for 0.5 h, and then taken out and cooled to room temperature to obtain a high-silica fiber-reinforced silica aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 95 wt%).

[0163] (6) The high-silica fiber-reinforced silica aerogel with a partial masking layer is placed in a pressure vessel 10, which is connected to a gas cylinder, an exhaust valve, a vacuum pump 70, and a buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 10) via a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0164] (7) Fill the pressure vessel 10 of step (6) with carbon dioxide until the pressure inside the vessel reaches 0.5 MPa, and maintain the pressure for 4 hours to promote the reaction between the main component of the partial masking layer and the carbon dioxide to obtain a dual-function partial masking layer (the main component of which is magnesium carbonate, with a content of about 95wt%).

[0165] (8) Open the drain valve of the pressure vessel 10 to drain the interior and restore the pressure to normal, then close the valve. Simultaneously, close the valve between the pressure vessel 10 and the buffer chamber 20 and place 0.95 g of trimethylchlorosilane into the open container in the buffer chamber 20.

[0166] (9) The buffer chamber 20 is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0167] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.09 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.07 MPa, and the modification time is 6 hours.

[0168] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through the tail gas treatment device 50 containing activated carbon. The purge time is 5 minutes; the tail gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0169] (12) The modified high-silica fiber-reinforced silica aerogel composite material block was taken out and placed in a hot air oven at 180°C for 1 hour to remove excess modifiers to obtain a high-silica fiber-reinforced silica aerogel material.

[0170] The mass of the high-silica fiber-reinforced silica aerogel obtained in this example is 21.6 g, and the thermal conductivity at 300°C is 0.0353 W / (m·K). -1 The contact angle is 116.8°, it is hydrophobic, the calorific value of combustion is 4.93MJ / kg, and there is no obvious flame or smoke in a high temperature environment (600℃).

[0171] Example 8

[0172] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0173] (1) The high silica fiber reinforced silica-aluminum composite aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 23.5 g, thermal conductivity at 300 ° C is 0.0462 W / (m·K) -1) was placed in a muffle furnace and heated to 400°C at a heating rate of 5°C / min and kept warm for 4 hours. The high-silica fiber reinforced silicon-aluminum composite aerogel material was prepared using an existing method, and the preparation steps included: mixing aluminum sec-butoxide, ethanol, and deionized water at a molar ratio of 1:6:0.6 at 60°C and stirring for 30 minutes to obtain aluminum sol. Subsequently, ethyl orthosilicate, ethanol, deionized water, and hydrochloric acid were mixed at room temperature at a molar ratio of 1:5:1:1.5×10 -3 Mix and stir for 30 minutes to obtain silica sol. The above aluminum sol and silica sol are mixed in a molar ratio of 4:1 to obtain a mixed sol. A mixture of methanol, glacial acetic acid and deionized water is added to the above mixed sol in a molar ratio of Al:methanol:glacial acetic acid:deionized water of 1:2.5::0.16:0.15 to obtain a silicon-aluminum composite sol. Use high silica fiber felt (0.11g / cm 3 ) was impregnated with the silica-alumina composite sol and placed in a mold to wait for gelation. After gelation, the mold was sealed and aged in an anhydrous ethanol solution for 24 hours. A high-silica fiber-reinforced silica-alumina composite aerogel material was obtained by drying using a supercritical drying device. This material was used as the aerogel material to be treated in Example 8.

[0174] (2) The heat-treated high-silica fiber-reinforced silica-alumina composite aerogel material was placed in an atomic layer deposition (ALD) chamber. Mg(CpEt)2 and ultrapure water served as the metal source and oxygen source, respectively. The chamber temperature was set at 180°C, Mg(CpEt)2 was heated to 90°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0175] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 5s-120s-200s-2.5s-120s-200s.

[0176] (4) After 70 cycles of deposition, a nano-oxide layer with a thickness of about 120 nm (its main component is magnesium oxide with a content of about 96 wt%) is prepared on the surface of the aerogel nanoparticle skeleton.

[0177] (5) The high-silica fiber reinforced silica-aluminum composite aerogel with the nano-magnesium oxide layer deposited was placed in a muffle furnace at 500°C, calcined for 0.5 h, and then taken out and cooled to room temperature to obtain a high-silica fiber reinforced silica-aluminum composite aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 96 wt%).

[0178] (6) The high-silica fiber-reinforced silica-aluminum composite aerogel with a partial masking layer is placed in a pressure vessel 10, which is connected to a gas cylinder, an exhaust valve, a vacuum pump 70, and a buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 10) via a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0179] (7) Carbon dioxide is injected into the pressure vessel 10 of step (6) to make the pressure inside the vessel reach 0.4 MPa, and the pressure is maintained for 6 hours to promote the reaction between the main component of the partial masking layer and the carbon dioxide to obtain a dual-function partial masking layer (whose main component is magnesium carbonate, with a content of about 96 wt%).

[0180] (8) Open the drain valve of the pressure vessel 10 to drain the interior and restore the pressure to normal, then close the valve. Simultaneously, close the valve between the pressure vessel 10 and the buffer chamber 20 and place 1.05 g of trimethylchlorosilane into the open container in the buffer chamber 20.

[0181] (9) The buffer chamber is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0182] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.08 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.07 MPa, and the modification time is 6 hours.

[0183] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through the tail gas treatment device 50 containing activated carbon. The purge time is 5 minutes; the tail gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0184] (12) The modified high-silica fiber reinforced silica-aluminum composite aerogel composite material block was taken out and placed in a hot air oven at 180°C for 1 hour to remove excess modifiers to obtain a high-silica fiber reinforced silica-aluminum composite aerogel material.

[0185] The mass of the high-silica fiber reinforced silica-aluminum composite aerogel obtained in Example 8 was 24.3 g, and the thermal conductivity at 300°C was 0.0473 W / (m·K). -1 The contact angle is 121.4°, it is hydrophobic, the calorific value of combustion is 6.12MJ / kg, and there is no obvious flame or smoke in a high temperature environment (800℃).

[0186] Example 9

[0187] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0188] (1) The aluminum silicate fiber reinforced silicon-aluminum composite aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 24.2 g, thermal conductivity at 300 ° C is 0.0477 W / (m·K) -1 ) was placed in a muffle furnace and heated to 400°C at a heating rate of 5°C / min and kept warm for 4 hours. The aluminum silicate fiber reinforced silicon-aluminum composite aerogel material was prepared using an existing method, and the preparation steps included: mixing aluminum sec-butoxide, ethanol, and deionized water at a molar ratio of 1:6:0.6 at 60°C and stirring for 30 minutes to obtain aluminum sol. Subsequently, ethyl orthosilicate, ethanol, deionized water, and hydrochloric acid were mixed at room temperature at a molar ratio of 1:5:1:1.5×10 -3 Mix and stir for 30 minutes to obtain silica sol. The above aluminum sol and silica sol are mixed in a molar ratio of 4:1 to obtain a mixed sol. A mixture of methanol, glacial acetic acid and deionized water is added to the above mixed sol in a molar ratio of Al:methanol:glacial acetic acid:deionized water of 1:2.5::0.16:0.15 to obtain a silicon-aluminum composite sol. Use high silica fiber felt (0.11g / cm 3 ) was impregnated with the aforementioned silica-alumina composite sol and placed in a mold to wait for gelation. After gelation, the mold was sealed and aged in anhydrous ethanol for 24 hours. Drying was performed using a supercritical drying apparatus to obtain an aluminum silicate fiber-reinforced silica-alumina composite aerogel material. This material served as the aerogel material to be treated in Example 9.

[0189] (2) The heat-treated aluminum silicate fiber-reinforced silica-aluminum composite aerogel material was placed in the atomic layer deposition (ALD) chamber, with bis(ethylcyclopentadienyl) magnesium (Mg(CpEt)2) serving as the metal source and ultrapure water as the oxygen source, respectively. The chamber temperature was set at 200°C, the bis(ethylcyclopentadienyl) magnesium was heated to 100°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0190] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 4.5s-120s-180s-2s-120s-180s.

[0191] (4) After 50 cycles of deposition, a nano-oxide layer with a thickness of about 80 nm (its main component is magnesium oxide with a content of about 97 wt%) is prepared on the surface of the aerogel nanoparticle skeleton.

[0192] (5) The aluminum silicate fiber reinforced silicon-aluminum composite aerogel with the nano-magnesium oxide layer deposited was placed in a muffle furnace at 500°C, calcined for 0.5 h, and then taken out and cooled to room temperature to obtain an aluminum silicate fiber reinforced silicon-aluminum composite aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 97 wt%).

[0193] (6) The aluminum silicate fiber reinforced silicon-aluminum composite aerogel with a partial masking layer is placed in a pressure vessel 10, and the pressure vessel 10 is connected to the gas cylinder, the emptying valve, the vacuum pump 70 and the buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 10) through a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0194] (7) Carbon dioxide is injected into the pressure vessel 10 of step (6) to make the pressure inside the vessel reach 0.5 MPa, and the pressure is maintained for 4 hours to promote the reaction between the main component of the partial masking layer and the carbon dioxide to obtain a dual-function partial masking layer (whose main component is magnesium carbonate, with a content of about 97 wt%).

[0195] (8) Open the drain valve of the pressure vessel 10 to drain the interior and restore the pressure to normal, then close the valve. Simultaneously, close the valve between the pressure vessel 10 and the buffer chamber 20, and place 0.9 g of trimethylchlorosilane into the open container in the buffer chamber 20.

[0196] (9) The buffer chamber 20 is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0197] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.08 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.07 MPa, and the modification time is 6 hours.

[0198] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through the tail gas treatment device 50 containing activated carbon. The purge time is 5 minutes; the tail gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0199] (12) The modified aluminum silicate fiber reinforced silicon-aluminum composite aerogel composite material block was taken out, placed in a hot air oven at 180°C, and baked for 1 hour to remove excess modifiers, thereby obtaining an aluminum silicate fiber reinforced silicon-aluminum composite aerogel material.

[0200] The mass of the aluminum silicate fiber reinforced silicon-aluminum composite aerogel obtained in this example is 25.1 g, and the thermal conductivity at 300°C is 0.0489 W / (m·K). -1 The contact angle is 117.2°, it is hydrophobic, the calorific value of combustion is 5.91MJ / kg, and there is no obvious flame or smoke in a high temperature environment (800℃).

[0201] Example 10

[0202] This embodiment provides a method for preparing a flame retardant hydrophobic aerogel material, comprising the following steps:

[0203] (1) The mullite fiber reinforced silicon-aluminum composite aerogel material to be treated (length * width * height: 200 * 200 * 3 mm, 25.3 g, thermal conductivity at 300 ° C is 0.0453 W / (m·K) -1 ) was placed in a muffle furnace and heated to 400°C at a heating rate of 5°C / min and kept warm for 4 hours. The mullite fiber reinforced silicon-aluminum composite aerogel material was prepared using an existing method, and the preparation steps included: mixing aluminum sec-butoxide, ethanol, and deionized water at a molar ratio of 1:6:0.6 at 60°C and stirring for 30 minutes to obtain aluminum sol. Subsequently, ethyl orthosilicate, ethanol, deionized water, and hydrochloric acid were mixed at room temperature at a molar ratio of 1:5:1:1.5×10 -3Mix and stir for 30 minutes to obtain silica sol. The above aluminum sol and silica sol are mixed in a molar ratio of 4:1 to obtain a mixed sol. A mixture of methanol, glacial acetic acid and deionized water is added to the above mixed sol in a molar ratio of Al:methanol:glacial acetic acid:deionized water of 1:2.5::0.16:0.15 to obtain a silicon-aluminum composite sol. Mullite fiber felt (0.11g / cm 3 ) was impregnated with the silica-alumina composite sol and placed in a mold to wait for gelation. After gelation, the mold was sealed and aged in anhydrous ethanol for 24 hours. A mullite fiber-reinforced silica-alumina composite aerogel material was obtained by drying using a supercritical drying device. This material was used as the aerogel material to be treated in Example 10.

[0204] (2) The heat-treated mullite fiber-reinforced silica-alumina composite aerogel material was placed in an atomic layer deposition (ALD) chamber, with biscyclopentadienyl magnesium (Mg(Cp)2) as the metal source and ozone as the oxygen source, respectively. The chamber temperature was set at 210°C, the biscyclopentadienyl magnesium was heated to 110°C, and pure nitrogen (99.99% purity) was used as the carrier gas and purge gas.

[0205] (3) One deposition cycle includes six steps: organometallic precursor pulse, rest, inert gas purge, oxygen-containing precursor pulse, rest, and inert precursor purge, with corresponding times of 4s-100s-200s-1.8s-100s-200s.

[0206] (4) Deposition was performed for 60 cycles to prepare a nano-oxide layer (mainly composed of magnesium oxide with a content of about 95 wt%) with a thickness of about 100 nm on the surface of the aerogel nanoparticle skeleton.

[0207] (5) The mullite fiber reinforced silicon-aluminum composite aerogel with the nano-magnesium oxide layer deposited was placed in a muffle furnace at 500°C, calcined for 0.5 h, and then taken out and cooled to room temperature to obtain a mullite fiber reinforced silicon-aluminum composite aerogel with a partial masking layer (whose main component is magnesium oxide, with a content of about 95wt%).

[0208] (6) The mullite fiber reinforced silicon-aluminum composite aerogel with a partial masking layer is placed in a pressure vessel 10, and the pressure vessel 10 is connected to the gas cylinder, the emptying valve, the vacuum pump 70 and the buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 10) through a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0209] (7) Fill the pressure vessel 10 of step (6) with carbon dioxide until the pressure inside the vessel reaches 0.5 MPa, and maintain the pressure for 4 hours to promote the reaction between the main component of the partial masking layer and the carbon dioxide to obtain a dual-function partial masking layer (the main component of which is magnesium carbonate, with a content of about 95wt%).

[0210] (8) Open the drain valve of the pressure vessel 10, drain the interior and restore the pressure to normal, then close the valve. Simultaneously, close the valve between the pressure vessel 10 and the buffer chamber 20, and place 1.1 g of dimethyldichlorosilane into the open container in the buffer chamber.

[0211] (9) The buffer chamber 20 is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0212] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.08 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.06 MPa, and the modification time is 5 hours.

[0213] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through the tail gas treatment device 50 containing activated carbon. The purge time is 5 minutes; the tail gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0214] (12) The modified mullite fiber reinforced silicon-aluminum composite aerogel composite material block was taken out, placed in a hot air oven at 180°C, and baked for 1 hour to remove excess modifiers to obtain a mullite fiber reinforced silicon-aluminum composite aerogel material.

[0215] The mass of the mullite fiber reinforced silicon-aluminum composite aerogel obtained in this example is 25.9 g, and the thermal conductivity at 300°C is 0.0471 W / (m·K). -1 The contact angle is 124.3°, it is hydrophobic, the calorific value of combustion is 6.21MJ / kg, and there is no obvious flame or smoke in a high temperature environment (800℃).

[0216] Comparative Example 1

[0217] The glass fiber reinforced silica aerogel to be treated in Example 1 was placed in a muffle furnace at 350° C. and heat treated for 3 hours to obtain the glass fiber reinforced silica aerogel material of Comparative Example 1.

[0218] The glass fiber reinforced silica aerogel material of this comparative example (length * width * height: 200 * 200 * 3 mm, 22.7 g, thermal conductivity at 300 ° C is 0.0323 W / (m·K) -1 It is hydrophilic, with a combustion calorific value of 2.61MJ / kg. In a high temperature environment (600℃), there is no obvious flame or smoke.

[0219] Comparative Example 2

[0220] The hydrophobic glass fiber reinforced silica aerogel material was prepared by the existing method as comparative example 2. The specific preparation method is as follows: methoxytrimethylsilane (MTMS), tetraethyl orthosilicate (TEOS), anhydrous ethanol and water were mixed in a molar ratio of 0.8:0.7:8:8 and stirred for 10 minutes. Subsequently, 1 mol / L nitric acid solution was added to adjust the pH to 3. After stirring at room temperature for 4 hours, 1 mol / L ammonia water was added to adjust the pH to 8 to obtain silica sol. The silica sol with a density of 0.08 g / cm 3 A glass fiber mat was impregnated with the silica sol and placed in a mold. After gelation, the mold was sealed and aged at 60°C for three days. After aging, the gel was removed and soaked in anhydrous ethanol for 8 hours to displace the solvent, repeating this process three times. After drying using a supercritical carbon dioxide drying apparatus, a hydrophobic glass fiber-reinforced silica aerogel material was obtained. This material was not treated in any way and served as Comparative Example 2.

[0221] The hydrophobic glass fiber reinforced silica aerogel material of this comparative example (length * width * height: 200 * 200 * 3 mm, 21.3 g, thermal conductivity at 300 ° C is 0.0331 W / (m·K) -1The contact angle is 134.6° and it is hydrophobic. The combustion calorific value is 17.4MJ / kg. In a high temperature environment (600℃), it produces open flames, the burning time is greater than 40s, and smoke is generated.

[0222] Comparative Example 3

[0223] This comparative example provides a method for preparing an aerogel material, comprising the following steps:

[0224] (1) A glass fiber reinforced silica aerogel material (length * width * height: 200 * 200 * 3 mm, 22.7 g) without hydrophobic treatment was placed in a muffle furnace and heated to 350 °C at a heating rate of 5 °C / min for 2 h.

[0225] (2) The heat-treated glass fiber reinforced silica aerogel is placed in a pressure vessel 10, which is connected to a gas cylinder, an exhaust valve, a vacuum pump 70, and a buffer chamber 20 (the volume of the buffer chamber 20 is 1 / 80 of the volume of the pressure vessel 10) via a valve. Specifically, the tail gas treatment device 50 is connected to the pressure vessel 10 through a first pipe, and the pressure vessel 10 is connected to the buffer chamber 20, the gas cylinder 40, the vacuum pump 70 and the carbon dioxide gas cylinder 80 through a second pipe, a third pipe, a fourth pipe and a fifth pipe respectively; a bracket 60 for placing the aerogel sample to be treated is provided in the pressure vessel 10, and the buffer chamber 20 and the gas cylinder 40 are connected through a sixth pipe; a first valve is provided on the first pipe between the tail gas treatment device 50 and the pressure vessel 10, a second valve is provided on the second pipe between the pressure vessel 10 and the buffer chamber 20, a third valve is provided on the third pipe between the pressure vessel 10 and the gas cylinder 40, a fourth valve is provided on the fourth pipe between the pressure vessel 10 and the vacuum pump 70, a fifth valve is provided on the fifth pipe between the pressure vessel 10 and the carbon dioxide gas cylinder 80, and a sixth valve 30 is provided on the sixth pipe between the buffer chamber 20 and the gas cylinder 40. Figure 4 .

[0226] (7) Close the valve between the pressure vessel 10 and the buffer chamber 20, and place 1.2 g of trimethylchlorosilane into the open container in the buffer chamber.

[0227] (9) The buffer chamber 20 is purged and filled with pure nitrogen (purity of 99.99%) for 5 seconds.

[0228] (10) Use the vacuum pump 70 to evacuate the pressure vessel 10 to approximately -0.09 MPa, close the air evacuation valve, and then open the valve between the buffer chamber 20 and the pressure vessel 10. Maintain the pressure in the pressure vessel 10 at approximately -0.07 MPa, and the modification time is 5 hours.

[0229] (11) After the modification is completed, pure nitrogen (purity of 99.99%) is introduced into the pressure vessel 10. After reaching normal pressure, the gas is discharged through the tail gas treatment device 50 containing activated carbon. The purge time is 5 minutes; the tail gas treatment device 50 is a gas filter containing 100g of activated carbon.

[0230] (12) The modified glass fiber reinforced silica aerogel composite material block was taken out and placed in a hot air oven at 180°C for 1 hour to remove excess modifiers to obtain a glass fiber reinforced silica aerogel material.

[0231] The glass fiber reinforced silica aerogel obtained in this comparative example has a contact angle of 131.7°, is hydrophobic, and has a combustion calorific value of 11.12 MJ / kg. In a high temperature environment (600°C), it generates an open flame and burns for more than 20 seconds without generating obvious smoke.

[0232] The hydrophobicity and combustion characteristics test data of the aerogel materials of Examples 1-10 and Comparative Examples 1-3 are summarized in Table 1. The mass and thermal conductivity data of the materials of Examples 1-10 before and after treatment are summarized in Table 2. As can be seen from the data in Table 1, the aerogel materials obtained in Examples 1-10 after treatment all have good hydrophobicity (contact angle > 90°) and low combustion heat (<6.5 MJ / kg). No open flame or large amounts of smoke appear in high-temperature environments, demonstrating flame retardancy. However, the aerogel material of Comparative Example 1, while having a low combustion heat, produces open flame and smoke at high temperatures, but is not hydrophobic. The aerogel material of Comparative Example 2, while hydrophobic, has a high combustion heat, produces open flame at high temperatures, and the flame lasts for a long time, and smoke is produced, demonstrating no flame retardancy. Open flame appears. Comparative Example 3 has hydrophobicity, but a high combustion heat, produces open flame and smoke at high temperatures, and also lacks flame retardancy. As can be seen from Table 2, the mass increase of each sample in Examples 1-10 after treatment is within 7%, and the increase in thermal conductivity is also within 8%, indicating that the hydrophobic, fire-resistant gas gel material prepared in each example does not significantly increase the density of the material and reduce the thermal insulation performance.

[0233] Table 1

[0234]

[0235] Table 2

[0236]

[0237]

[0238] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0239] The numerical ranges described in the present invention include all values within the range, and include range values formed by any two values within the range. Different numerical values of the same indicator appearing in all embodiments of the present invention can be arbitrarily combined to form a range value.

[0240] The technical features in the claims and / or the specification of the present invention may be combined, and the manner of combination is not limited to the combination obtained by reference in the claims. The technical solutions obtained by combining the technical features in the claims and / or the specification are also within the scope of protection of the present invention.

[0241] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a flame retardant hydrophobic aerogel material, characterized in that: The following steps are involved: 1) heat-treating the aerogel material to be processed; 2) depositing a nano-oxide layer on the surface of the heat-treated aerogel material; 3) converting the nano-oxide layer on the surface of the aerogel material into a partial masking layer; 4) converting a partial masking layer on the surface of the aerogel material into a dual-functional partial masking layer; 5) The aerogel material having the dual-functional partial masking layer is subjected to vacuum vapor modification, followed by post-treatment to obtain the flame-retardant hydrophobic aerogel material.

2. The method for preparing a flame retardant hydrophobic aerogel material according to claim 1, wherein: In step 1), the heat treatment comprises the following steps: The aerogel material to be treated is heated to 350-400°C at a heating rate of 5-10°C / min and kept warm for 2-4 hours.

3. The method for preparing a flame retardant hydrophobic aerogel material according to claim 2, wherein: In step 2), the nano-oxide layer contains more than 90wt% of magnesium oxide and has a thickness of 50-200nm; the deposition is atomic layer deposition, with an organic metal precursor and an oxygen-containing precursor as the metal source and the oxygen source, respectively, and an inert gas as the carrier gas and the purge gas; the organic metal precursor is bis(ethylcyclopentadienylmagnesium) or bis(cyclopentadienylmagnesium); the oxygen-containing precursor is water or ozone; and the inert gas is argon or nitrogen.

4. The method for preparing a flame retardant hydrophobic aerogel material according to claim 3, wherein: In step 2), the deposition temperature is 80-150°C; the deposition cycle includes six steps: organometallic precursor pulse, standing, inert gas purge, oxygen-containing precursor pulse, standing, and inert precursor purge, and the corresponding times are (2-10s)-(>80s)-(>150s)-(0.8-3s)-(>80s)-(>150s); the deposition cycle is 10-60 cycles.

5. The method for preparing the flame retardant hydrophobic aerogel material according to claim 3, wherein: In step 3), the partial masking layer contains more than 90 wt% of magnesium oxide, which is obtained by sintering and converting the magnesium oxide nano-oxide layer obtained in step 2); the conversion temperature is 450-500° C. and the time is 0.5-1 hour; in step 4), the dual-function partial masking layer contains more than 90 wt% of magnesium carbonate; It is obtained by reacting the magnesium oxide partial masking layer obtained in step 3); the conversion pressure is 0.2-0.5 MPa, and the time is 2-4 hours.

6. The method for preparing the flame retardant hydrophobic aerogel material according to claim 1, wherein: In step 5), the vacuum vapor modification step comprises: The aerogel material with a dual-functional partial masking layer is modified in a vacuum gas phase by selectively modifying the hydrophobic group with a modifying agent under low pressure conditions; then an inert gas is introduced for purging.

7. The method for preparing the flame retardant hydrophobic aerogel material according to claim 6, wherein: In step 5), the amount of the modifier added is 1 / 30-1 / 10 of the mass of the aerogel material having a dual-functional partial masking layer.

8. The method for preparing the flame retardant hydrophobic aerogel material according to claim 6, wherein: In step 5), the low-pressure vacuum pressure is -0.07 MPa to -0.05 MPa, the modification time is 2-6 hours, the purge time is more than 5 minutes, and the post-treatment temperature is 150-250° C., and the time is more than 1 hour.

9. A flame retardant hydrophobic aerogel material, characterized in that: The flame-retardant hydrophobic aerogel material has a contact angle greater than 120°, a combustion calorific value less than 6 MJ / kg, and no obvious flame or smoke at a temperature greater than 600° C. The flame-retardant hydrophobic aerogel material is prepared by the method according to any one of claims 1 to 8.

10. A thermal insulation material, characterized in that: The thermal insulation material adopts a flame-retardant hydrophobic aerogel material. The flame-retardant hydrophobic aerogel material has a contact angle greater than 120°, a combustion calorific value less than 6MJ / kg, and no obvious flame or smoke at a temperature greater than 600°C.

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