Mullite whiskers GO-ZrO2-SiO2 composite aerogel felt as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of composite materials, and discloses a mullite whiskers GO-ZrO2-SiO2 composite aerogel felt as well as a preparation method and application thereof. The mullite whiskers GO-ZrO2-SiO2 composite aerogel felt provided by the invention is prepared from a silver doped fiber felt and mullite whiskers GO-ZrO2-SiO2 composite aerogel loaded on the silver doped fiber felt, and the silver doped fiber felt and the mullite whiskers GO-ZrO2-SiO2 composite aerogel are loaded on the mullite whiskers GO-ZrO2-SiO2 composite aerogel loaded on the mullite whiskers GO-ZrO2-SiO2 composite aerogel loaded on the silver doped fiber felt. The mullite whiskers GO-ZrO2-SiO2 composite aerogel felt has excellent heat insulation performance, structural stability, mechanical performance and antibacterial performance, and has a huge application prospect in preparation of an ultrahigh-temperature heat-resistant material.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a mullite whisker-GO-ZrO2-SiO2 composite aerogel felt and a preparation method and application thereof. Background Art

[0002] Aerogel refers to a nano-scale porous solid material formed by using the sol-gel method and a certain drying method to allow gas to replace the solvent in the gel. It has the advantages of large specific surface area, high porosity and low density. It is widely used in thermal insulation, adsorption, catalysis, sound absorption and other fields.

[0003] Aerogels can be categorized as inorganic, organic, and carbon based on their skeleton composition. Compared to traditional thermal insulation systems like rock wool, polyurethane foam, and ceramic fiber, silica aerogel maintains structural stability over a wide temperature range below 600°C. It also boasts ultra-low thermal conductivity and density, providing superior insulation at lower thicknesses. This makes compact equipment design possible, making it an irreplaceable material in fields like precision instruments, aerospace, and battery insulation.

[0004] However, silica aerogel materials have defects such as low strength, high brittleness, difficulty in processing and weak bonding with the base material. Moreover, under ultra-high temperature conditions above 600°C, there is a possibility of pore structure collapse, resulting in loss of thermal insulation effect. This greatly limits the application of silica aerogel materials in ultra-high temperature thermal insulation materials and has great limitations. Summary of the Invention

[0005] The first purpose of the present invention is to solve the problems existing in existing silica aerogel materials, such as low strength, high brittleness, weak bonding with the felt base material, and uncontrollable thermal insulation effect under ultra-high temperature conditions, and provide a mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

[0006] The second object of the present invention is to provide a method for preparing the above-mentioned mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

[0007] The third object of the present invention is to provide a composite silica aerogel felt.

[0008] A fourth object of the present invention is to provide a method for preparing the composite silica aerogel felt.

[0009] The fifth object of the present invention is to provide the use of the above-mentioned mullite whisker-GO-ZrO2-SiO2 composite aerogel felt or composite silica aerogel felt in the preparation of thermal insulation materials.

[0010] Specifically, the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided by the present invention includes a silver-doped fiber felt and a mullite whisker-GO-ZrO2-SiO2 composite aerogel, and the mullite whisker-GO-ZrO2-SiO2 composite aerogel is loaded on the silver-doped fiber felt.

[0011] Furthermore, the silver loading on the silver-doped fiber felt is 0.5 mg / cm 3 ~150mg / cm 3 .

[0012] Furthermore, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel on the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt is 5 mg / cm 3 ~400mg / cm 3 .

[0013] The preparation method of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided by the present invention comprises the following steps: S1, taking a silver ion aqueous solution to perform an impregnation treatment on a high-temperature resistant fiber felt to obtain a silver ion-impregnated fiber felt, and taking a reducing agent solution to perform a reduction reaction on the silver ion-impregnated fiber felt to obtain the silver-doped fiber felt; S2, mixing a ZrO2 sol, a graphene oxide dispersed aqueous solution and a silicon source aqueous solution to obtain a mixed solution; performing a gelation reaction on the mixed solution to obtain a GO-ZrO2-SiO2 sol; mixing mullite whiskers with the GO-ZrO2-SiO2 sol to obtain a mixed sol; performing a loading treatment on the silver-doped fiber felt with the mixed sol to obtain a composite aerogel felt precursor; and performing an aging treatment, a solvent replacement treatment, a hydrophobic modification treatment and a drying treatment on the composite aerogel felt precursor to obtain the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

[0014] Furthermore, in step S1, the concentration of silver ions in the silver ion aqueous solution is 0.01 mol / L to 1 mol / L.

[0015] Furthermore, in step S1, the high temperature resistant fiber felt includes one or more of mullite fiber felt, basalt fiber felt and aluminum silicate fiber felt.

[0016] Furthermore, in step S1, the impregnation method includes: immersing the high-temperature resistant fiber felt in a silver ion aqueous solution, performing an oscillation treatment for 60 minutes to 300 minutes and an ultrasonic treatment for 1 minute to 120 minutes to obtain the silver ion-impregnated fiber felt.

[0017] Furthermore, in step S1, the reducing agent solution includes one or more of ascorbic acid, sodium citrate and glucose.

[0018] Furthermore, in step S1, the concentration of the reducing agent in the reducing agent solution is 0.01 mol / L to 6 mol / L.

[0019] Furthermore, in step S1, the reduction reaction temperature is 50° C. to 100° C., and the time is 1 h to 6 h.

[0020] Furthermore, in step S2, in the graphene oxide dispersed aqueous solution, the oxidation degree of graphene oxide is 10% to 50%, the thickness of the flakes is 0.1 nm to 3 nm, and the particle size is 50 μm to 300 μm.

[0021] Furthermore, in step S2, the addition ratio of the ZrO2 sol and the silicon source aqueous solution is 1:(1-5) based on the addition molar ratio of Zr and Si, and the addition amount of the graphene oxide dispersed aqueous solution is 0.1%-10% based on the mass of graphene oxide to the theoretically generated mass of silicon dioxide.

[0022] Furthermore, in step S2, the gelation reaction method includes: slowly adding an acid solution to the mixed solution under stirring until the pH value reaches 1 to 5, and performing a gelation reaction under stirring for 0.1 h to 5 h to obtain the GO-ZrO2-SiO2 sol.

[0023] Furthermore, in step S2, the acid solution includes one or more of hydrochloric acid, sulfuric acid and phosphoric acid.

[0024] Furthermore, in step S2, the preparation of the mullite whiskers includes: mixing an aluminum source compound, silicon dioxide and a mineralizer, and performing a calcination treatment to obtain the mullite whiskers.

[0025] Furthermore, in step S2, in the preparation of the mullite whiskers, the aluminum source compound includes one or more of Al2(SO4)3, Al(NO3)3 and AlCl3.

[0026] Furthermore, in step S2, in the preparation of the mullite whiskers, the mineralizer includes one or more of K2SO4, NaCl, KCl, Na2SO4 and LiF.

[0027] Furthermore, in step S2, in the preparation of the mullite whiskers, the molar ratio of Al to Si in the aluminum source compound and silica is (1-5):1, and the mass ratio of the mineralizer to the sum of the aluminum source compound and silica is (1-5):1.

[0028] Furthermore, in step S2, in the preparation of the mullite whiskers, the heating rate of the calcination treatment is 5°C / min to 10°C / min, the holding temperature is 600°C to 1200°C, and the holding time is 1h to 8h.

[0029] Furthermore, in step S2, the concentration of the mullite whiskers in the mixed sol is 1 wt% to 10 wt%.

[0030] Furthermore, in step S2, a flame retardant is added to the mixed sol, and the flame retardant includes one or more of phosphorus-based inorganic flame retardants, borate-based inorganic flame retardants, halogen-based organic flame retardants, and phosphorus-nitrogen-based organic flame retardants.

[0031] Furthermore, in step S2, the concentration of the flame retardant in the mixed sol is 0.1 wt% to 10 wt%.

[0032] Furthermore, in step S2, a gel accelerator is added to the mixed sol, and the gel accelerator includes one or more of epoxybutene, glycidol, propylene oxide and polyacrylic acid.

[0033] Furthermore, in step S2, in the mixed sol, the molar ratio of the gel accelerator to the sum of Zr—Si is 1:(1-5).

[0034] Furthermore, in step S2, the loading treatment method includes: taking the silver-doped fiber felt and immersing it in the mixed sol for 1 minute to 30 minutes, and then performing a roller pressing treatment to make the rolling rate of the mixed sol on the silver-doped fiber felt 50% to 70%, taking the silver-doped fiber felt loaded with the mixed sol and performing a static treatment for 20 minutes to 120 minutes to obtain the composite aerogel felt precursor.

[0035] Furthermore, in step S2, the aging treatment method includes: mixing an aging agent with the composite aerogel felt precursor, performing a sealing aging treatment at 15°C to 35°C for 12h to 48h, and performing a hydrothermal treatment at 120°C to 200°C for 12h to 48h.

[0036] Furthermore, in step S2, in the aging treatment, the aging agent includes one or more of ethanol, toluene, acetone and the mixed solution.

[0037] Furthermore, in step S2, during the aging treatment, the volume ratio of the aging agent to the composite aerogel felt precursor is (1-5):1.

[0038] Furthermore, in step S2, the solvent replacement treatment method includes: mixing ethanol with the composite aerogel felt precursor that has undergone the aging treatment, performing replacement at 15°C to 35°C for 12 to 96 hours, and replacing the ethanol every 12 to 24 hours.

[0039] Furthermore, in step S2, in the solvent replacement treatment, the volume ratio of the ethanol to the composite aerogel felt precursor that has undergone the aging treatment is (1-10):1.

[0040] Furthermore, in step S2, the hydrophobic modification method includes: mixing a hydrophobic modification liquid with the composite aerogel felt precursor that has undergone the solvent replacement treatment, performing a hydrophobic modification treatment at 10°C to 50°C for 1 hour to 40 hours, and replacing the hydrophobic modification liquid every 1 hour to 10 hours.

[0041] Furthermore, in step S2, the drying method includes: taking the composite aerogel felt precursor that has undergone the hydrophobic modification treatment and performing a first vacuum drying treatment at 25°C to 35°C for 1h to 3h, performing a second vacuum drying treatment at 45°C to 55°C for 1h to 3h, performing a third vacuum drying treatment at 55°C to 65°C for 2h to 4h, and performing a fourth vacuum drying treatment at 75°C to 85°C for 2h to 4h to obtain the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

[0042] The composite silica aerogel felt provided by the present invention comprises the above-mentioned mullite whisker-GO-ZrO2-SiO2 composite aerogel felt and silver-doped fiber felt, wherein the silver-doped fiber felt is arranged on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

[0043] The preparation method of the composite silica aerogel felt provided by the present invention comprises: applying a high-temperature adhesive to both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt, and pasting the silver-doped fiber felt on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt to obtain the composite silica aerogel felt.

[0044] The present invention also provides the use of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt or composite silica aerogel felt in the preparation of thermal insulation materials.

[0045] Beneficial effects:

[0046] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided by the present invention, mullite whiskers, GO and ZrO2 are introduced into the silica aerogel to form a continuous three-dimensional network inside the aerogel. The mullite whiskers, GO and ZrO2 play a bridging role to disperse external stress and inhibit the propagation of internal cracks, thereby improving the mechanical properties of the mullite whisker-GO-ZrO2-SiO2 composite aerogel and enhancing the stability of the nanoporous structure of the obtained composite aerogel under ultra-high temperature conditions above 650°C and the resistance to near The silver-doped fiber felt has the ability to block infrared thermal radiation, and there is excellent bonding between the silver-doped fiber felt and the mullite whisker-GO-ZrO2-SiO2 composite aerogel. The mullite whisker-GO-ZrO2-SiO2 composite aerogel can be stably loaded on the silver-doped fiber felt, and the introduced silver has a certain antibacterial ability, so as to give the obtained mullite whisker-GO-ZrO2-SiO2 composite aerogel felt excellent thermal insulation performance, structural stability, mechanical properties and antibacterial properties, and has great application prospects in the preparation of ultra-high temperature heat-resistant materials.

[0047] In some specific embodiments, the present invention also provides a method for preparing a mullite whisker-GO-ZrO2-SiO2 composite aerogel felt. The preparation method first fully impregnates the high-temperature resistant fiber felt with silver ions, and uses a reducing agent to perform an in-situ reaction on the high-temperature resistant fiber felt to uniformly and stably dope silver on the high-temperature resistant fiber felt to obtain a silver-doped fiber felt; then a staged process is used to prepare the mullite whisker-GO-ZrO2-SiO2 sol - ZrO2 sol and graphene oxide dispersed aqueous solution are introduced before the silicon source aqueous solution is gelled, so that ZrO2 and graphene oxide can be uniformly embedded in the silica aerogel as a rigid skeleton. In the porous network of the gel, the agglomeration and sintering of silica particles are effectively inhibited, thereby maintaining the integrity of the pore structure and obtaining a preliminarily gelled mixed sol. The mixed sol is then mixed with mullite whiskers and loaded on the silver-doped fiber felt, so that the complete gelation of the mullite whisker-GO-ZrO2-SiO2 sol occurs on the silver-doped fiber felt. Through the interaction between mullite whiskers, ZrO2 and silver, the stable loading of mullite whisker-GO-ZrO2-SiO2 aerogel on the high-temperature resistant fiber felt is achieved, further improving the bonding stability between the mullite whisker-GO-ZrO2-SiO2 aerogel and the fiber felt.

[0048] In some specific embodiments, the present invention also provides a composite silica aerogel felt, which forms a sandwich structure by arranging silver-doped fiber felt on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt, thereby preventing the mullite whisker-GO-ZrO2-SiO2 composite aerogel from falling off, further improving the bonding stability between the mullite whisker-GO-ZrO2-SiO2 composite aerogel and the fiber felt substrate, and maintaining the pore structure inside the mullite whisker-GO-ZrO2-SiO2 composite aerogel. While maintaining the excellent thermal insulation and mechanical properties of the composite felt, the bonding stability between the mullite whisker-GO-ZrO2-SiO2 and the fiber felt can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the layer structure of the composite silica aerogel felt provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0050] The mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided by the present invention specifically comprises a silver-doped fiber felt and a mullite whisker-GO-ZrO2-SiO2 composite aerogel, wherein the mullite whisker-GO-ZrO2-SiO2 composite aerogel is loaded on the silver-doped fiber felt.

[0051] In the present invention, the silver loading on the silver-doped fiber felt is preferably 0.5 mg / cm 3 ~150mg / cm 3 , specifically 0.5 mg / cm 3 , 1mg / cm 3 , 2mg / cm 3 , 4mg / cm 3 , 1.5mg / cm 3 , 2.5mg / cm 3 , 5mg / cm 3 , 75mg / cm 3 、100mg / cm 3 、150mg / cm 3 At this time, the silver-doped fiber felt and the mullite whisker-GO-ZrO2-SiO2 composite aerogel have better bonding properties.

[0052] In the present invention, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel on the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt is preferably 5 mg / cm 3 ~400mg / cm 3 , specifically 5mg / cm 3、10mg / cm 3 、15mg / cm 3 , 25mg / cm 3 、50mg / cm 3 , 75mg / cm 3 、100mg / cm 3 、150mg / cm 3 , 200mg / cm 3 , 250mg / cm 3 、300mg / cm 3 or any value in between.

[0053] The present invention also provides a preparation method of the above-mentioned mullite whisker-GO-ZrO2-SiO2 composite aerogel felt, which specifically includes: S1, taking a silver ion aqueous solution to impregnate a high-temperature resistant fiber felt to obtain a silver ion-impregnated fiber felt, taking a reducing agent solution to perform a reduction reaction on the silver ion-impregnated fiber felt to obtain the silver-doped fiber felt; S2, taking a ZrO2 sol, a graphene oxide dispersed aqueous solution and a silicon source aqueous solution to mix to obtain a mixed solution; taking the mixed solution to perform a gelation reaction to obtain a GO-ZrO2-SiO2 sol; taking mullite whiskers and GO-ZrO2-SiO2 sol to mix to obtain a mixed sol; taking the mixed sol to load the silver-doped fiber felt to obtain a composite aerogel felt precursor; taking the composite aerogel felt precursor to perform an aging treatment, a solvent replacement treatment, a hydrophobic modification treatment and a drying treatment to obtain the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

[0054] In the present invention, in step S1, the concentration of silver ions in the silver ion aqueous solution is preferably 0.01 mol / L to 1 mol / L, and specifically can be 0.01 mol / L, 0.05 mol / L, 0.08 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.8 mol / L, 1 mol / L, or any value therebetween. In this case, the silver ions can be better loaded onto the high-temperature resistant fiber felt, thereby increasing the silver loading amount in the final silver-doped fiber felt.

[0055] In the present invention, in step S1, the high-temperature resistant fiber felt refers to a flexible material made of high-temperature resistant fiber, which is a material widely used in high-temperature environments in the prior art. The present invention does not impose any special limitation on it. Specific examples include but are not limited to: one or more of mullite fiber felt, basalt fiber felt and aluminum silicate fiber felt.

[0056] In the present invention, in step S1, the impregnation treatment is a technical means commonly used in existing fabric treatment, which is limited to achieving the loading of silver ions on the high-temperature resistant fiber felt, and the present invention does not impose any special limitation on it.

[0057] In some specific embodiments, the impregnation method preferably includes: immersing the high-temperature resistant fiber felt in a silver ion aqueous solution, performing an oscillation treatment for 60 minutes to 300 minutes and an ultrasonic treatment for 1 minute to 120 minutes, to obtain the silver ion-impregnated fiber felt. The oscillation treatment is achieved using an existing oscillator, and the ultrasonic treatment is achieved using an existing ultrasonic agitator. Those skilled in the art can adjust the relevant parameters of the instrument according to actual needs, and the present invention does not impose any particular limitations. At this point, the silver ion aqueous solution achieves the effect of fully impregnating the high-temperature resistant fiber felt, which is conducive to achieving a high silver load on the high-temperature resistant fiber felt.

[0058] In the present invention, in step S1, the reducing agent solution includes a reducing agent capable of reducing silver ions to silver. Specific examples of the reducing agent include, but are not limited to, one or more of ascorbic acid, sodium citrate, and glucose.

[0059] In some specific embodiments, in step S1, the concentration of the reducing agent in the reducing agent solution is preferably 0.01 mol / L to 6 mol / L, specifically 0.01 mol / L, 0.05 mol / L, 0.08 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 1 mol / L, 3 mol / L, 5 mol / L, 6 mol / L, or any value therebetween. In this case, the reducing agent can better react with the silver ions loaded on the high-temperature resistant fiber felt, further optimizing the silver doping and distribution on the high-temperature resistant fiber felt, and improving the quality of the resulting silver-doped fiber felt.

[0060] In some specific embodiments, in step S1, the reduction reaction conditions include a temperature of preferably 50°C to 100°C, specifically 50°C, 58°C, 60°C, 65°C, 70°C, 78°C, 85°C, 90°C, 100°C or any value therebetween; and a time of preferably 1h to 6h, specifically 1h, 1.2h, 1.5h, 1.8h, 2h, 2.5h, 3h, 4h, 5h, 6h or any value therebetween.

[0061] In the present invention, in step S2, the ZrO sol refers to a stable system with colloidal properties formed by ZrO nanoparticles dispersed in a liquid medium. The method for preparing the ZrO sol is a technical means conventionally used in the prior art, and the present invention does not impose any particular limitation on the specific method of obtaining the ZrO sol.

[0062] In the present invention, in step S2, the graphene oxide dispersed aqueous solution refers to a stable mixed system formed by graphene oxide uniformly dispersed in water. The method for preparing the graphene oxide dispersed aqueous solution is a technical means conventionally used in the prior art, and the present invention does not impose any particular limitation on its specific method of obtaining it.

[0063] In some specific embodiments, in step S2, in the graphene oxide dispersed aqueous solution, the oxidation degree of graphene oxide is preferably 10% to 50%, specifically 10%, 12%, 15%, 18%, 20%, 30%, 40%, 50% or any value therebetween; the flake thickness is preferably 0.1 nm to 3 nm, specifically 0.1 nm, 0.3 nm, 0.5 nm, 0.7 nm, 0.9 nm, 1 nm, 1.3 nm, 1.5 nm, 1.8 nm, 2 nm, 2.5 nm, 3 nm or any value therebetween; the particle size is preferably 50 μm to 300 μm, specifically 50 μm, 55 μm, 60 μm, 70 μm, 80 μm, 100 μm, 120 μm, 150 μm, 200 μm, 250 μm, 300 μm or any value therebetween. At this time, the graphene oxide can be better doped into the porous network of the silica aerogel, further improving the stability of the obtained mullite whisker-GO-ZrO2-SiO2 composite aerogel and its shielding ability against near-infrared thermal radiation.

[0064] In the present invention, in step S2, the addition ratio of the ZrO2 sol and the silicon source aqueous solution is preferably 1:(1-5) based on the added molar ratio of Zr to Si, specifically 1:1, 1:1.3, 1:1.5, 1:1.8, 1:2, 1:3, 1:3.8, 1:4, 1:5, or any value therebetween; the addition amount of the graphene oxide dispersed aqueous solution is preferably 0.1% to 10% based on the mass of graphene oxide to the theoretical mass of generated silicon dioxide, specifically 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.3%, 2.5%, 3%, 5%, 6%, 8%, 10%, or any value therebetween. At this time, the ZrO2 and graphene oxide have a more ideal doping and modification effect on the silica aerogel.

[0065] In the present invention, in step S2, the gelation reaction refers to the process of transforming the mixed solution from a liquid state to a gel state having a three-dimensional network structure. It is a technical means commonly used in the preparation of silica aerogels and is not particularly limited in the present invention.

[0066] In some specific embodiments, in step S2, the gelation reaction method preferably includes: slowly adding an acid solution to the mixed solution under stirring until the pH value is 1 to 5, and performing a gelation reaction under stirring for 0.1 h to 5 h to obtain the GO-ZrO2-SiO2 sol. The acid solution is used to provide H for the gelation reaction. + Specific examples include, but are not limited to, one or more of hydrochloric acid, sulfuric acid, and phosphoric acid.

[0067] In the present invention, in step S2, the mullite whiskers refer to aluminum silicates with a needle-like or fibrous regular crystal structure, which are a type of material widely used in the fields of existing composite materials, ceramics, electronics, etc. The present invention does not impose any special limitation on them.

[0068] In the present invention, in step S2, the method for preparing the mullite whiskers preferably includes: mixing an aluminum source compound, silicon dioxide, and a mineralizer, and calcining the mixture to obtain the mullite whiskers. Specific examples of the aluminum source compound include, but are not limited to, one or more of Al2(SO4)3, Al(NO3)3, and AlCl3. Specific examples of the mineralizer include, but are not limited to, one or more of K2SO4, NaCl, KCl, Na2SO4, and LiF.

[0069] In some specific embodiments, in the preparation of the mullite whiskers, the molar ratio of Al and Si in the aluminum source compound and silica is preferably (1-5):1, specifically 1:1, 2:1, 3:1, 4:1, 5:1 or any value therebetween; the mass ratio of the mineralizer to the sum of the aluminum source compound and silica is preferably (1-5):1, specifically 1:1, 2:1, 4:1, 5:1 or any value therebetween.

[0070] In some specific embodiments, in the preparation of the mullite whiskers, the calcination treatment conditions include a heating rate of preferably 5°C / min to 10°C / min, specifically 5°C / min, 5.5°C / min, 6°C / min, 7°C / min, 8°C / min, 10°C / min or any value therebetween; a holding temperature of preferably 600°C to 1200°C, specifically 600°C, 650°C, 700°C, 800°C, 1000°C, 1200°C or any value therebetween; and a holding time of preferably 1h to 8h, specifically 1h, 3h, 5h, 7h, 8h or any value therebetween.

[0071] In the present invention, in step S2, the concentration of mullite whiskers in the mixed sol is preferably 1wt% to 10wt%, specifically 1wt%, 1.2wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 4wt%, 6wt%, 8wt%, 10wt% or any value therebetween.

[0072] In the present invention, in step S2, a flame retardant is preferably added to the mixed sol. The flame retardant refers to a class of compounds that have the effect of preventing substances from burning. It is a type of agent commonly used in the prior art. Specific examples include, but are not limited to, one or more of phosphorus-based inorganic flame retardants, borate-based inorganic flame retardants, halogen-based organic flame retardants, and phosphorus-nitrogen-based organic flame retardants. In this case, the addition of the flame retardant can synergize with the mullite whisker-GO-ZrO2-SiO2 composite aerogel to impart excellent flame retardant properties to the resulting mullite whisker-GO-ZrO2-SiO2 composite aerogel.

[0073] In some specific embodiments, in step S2, the concentration of the flame retardant in the mixed sol is preferably 0.1wt% to 10wt%, specifically 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 3wt%, 5wt%, 8wt%, 10wt% or any value therebetween.

[0074] In the present invention, in step S2, a gelling accelerator is preferably added to the mixed sol. The gelling accelerator is a substance that accelerates and optimizes the gelling process and is a commonly used agent in the prior art. Specific examples include, but are not limited to, one or more of epoxybutene, glycidol, propylene oxide, and polyacrylic acid. The addition of the gelling accelerator effectively gels the mixed sol on the silver-doped fiber mat, further enhancing the bonding stability between the mullite whisker-GO-ZrO₂-SiO₂ and the fiber mat.

[0075] In some specific embodiments, in step S2, in the mixed sol, the molar ratio of the gel accelerator to the sum of Zr-Si is preferably 1:(1-5), specifically 1:1, 1:1.2, 1:1.5, 1:2, 1:2.5, 1:3, 1:4, 1:5 or any value therebetween.

[0076] In the present invention, in step S2, the loading treatment refers to the process in which the mixed sol fully enters the interior of the silver-doped fiber felt and undergoes further gelation. It is a technical means commonly used in existing fabric finishing and is not particularly limited in the present invention.

[0077] In some specific embodiments, in step S2, the loading treatment method preferably includes: immersing the silver-doped fiber felt in the mixed sol for 1 to 30 minutes, then performing a roller pressing process to achieve a residual rate of 50 to 70% of the mixed sol on the silver-doped fiber felt; and allowing the silver-doped fiber felt loaded with the mixed sol to stand for 20 to 120 minutes to obtain the composite aerogel felt precursor. The roller pressing process is performed using an existing roller pressing machine. Those skilled in the art can adjust the relevant parameters of the machine according to actual needs, and the present invention is not particularly limited thereto.

[0078] In the present invention, in step S2, the aging treatment refers to a process of further cross-linking and reorganizing the chemical bonds inside the aerogel, thereby improving the structural stability of the aerogel. It is a technical means commonly used in the preparation of silica aerogels and is not particularly limited in the present invention.

[0079] In some specific embodiments, in step S2, the aging treatment method preferably includes: mixing an aging agent with the composite aerogel felt precursor, performing a sealed aging treatment at 15°C to 35°C for 12 hours to 48 hours, and performing a hydrothermal treatment at 120°C to 200°C for 12 hours to 48 hours. Specific examples of the aging agent include, but are not limited to, one or more of ethanol, toluene, acetone, and the mixed solution.

[0080] In some preferred embodiments, during the aging treatment in step S2, the volume ratio of the aging agent to the composite aerogel felt precursor is preferably (1-5):1, specifically 1:1, 2:1, 3:1, 4:1, 5:1, or any value therebetween. In this case, a better structural optimization effect can be achieved for the mullite whisker-GO-ZrO2-SiO2 composite aerogel.

[0081] In the present invention, in step S2, the solvent replacement treatment refers to the process of replacing the initial solvent in the pores of the wet gel with an organic solvent with low surface tension. It is a technical means commonly used in the preparation of silica aerogels and is not particularly limited in the present invention.

[0082] In some specific embodiments, the solvent replacement treatment method preferably includes: mixing ethanol with the composite aerogel felt precursor that has undergone the aging treatment, performing the replacement at 15° C. to 35° C. for 12 to 96 hours, and replacing the ethanol every 12 to 24 hours;

[0083] In some preferred embodiments, in the solvent replacement treatment of step S2, the volume ratio of the ethanol to the aged composite aerogel felt precursor is preferably (1-10):1, specifically 1:1, 2:1, 4:1, 5:1, 8:1, 10:1, or any value therebetween. In this case, a better solvent replacement effect can be achieved for the mullite whisker-GO-ZrO2-SiO2 composite aerogel.

[0084] In the present invention, in step S2, the drying treatment refers to the process of removing the solvent in the composite aerogel felt precursor to convert the mullite whisker-GO-ZrO2-SiO2 composite aerogel loaded thereon into a dry gel with a nanoporous structure. It is a technical means commonly used in the preparation of silica aerogels and is not particularly limited in the present invention.

[0085] In some specific embodiments, in step S2, the drying method preferably includes: taking the composite aerogel felt precursor that has undergone the hydrophobic modification and performing a first vacuum drying treatment at 25°C to 35°C for 1 hour to 3 hours, performing a second vacuum drying treatment at 45°C to 55°C for 1 hour to 3 hours, performing a third vacuum drying treatment at 55°C to 65°C for 2 hours to 4 hours, and performing a fourth vacuum drying treatment at 75°C to 85°C for 2 hours to 4 hours to obtain the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt. At this time, the drying treatment is carried out in a staged manner, which can well maintain the nanoporous structure of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt during the drying process.

[0086] It should be noted that the above-mentioned preparation method of mullite whisker-GO-ZrO2-SiO2 composite aerogel felt only discloses the key steps for preparing mullite whisker-GO-ZrO2-SiO2 composite aerogel felt with excellent thermal insulation performance, structural stability, mechanical properties and antibacterial properties. Those skilled in the art can add other processing steps according to actual needs based on the contents disclosed in the present invention.

[0087] The present invention also provides a composite silica aerogel felt comprising the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt and a silver-doped fiber felt, wherein the silver-doped fiber felt is disposed on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt. The silver-doped fiber felt disposed on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt further improves the bonding stability between the mullite whisker-GO-ZrO2-SiO2 composite aerogel and the fiber felt substrate, while maintaining the pore structure within the mullite whisker-GO-ZrO2-SiO2 composite aerogel.

[0088] The present invention also provides a preparation method of the above-mentioned composite silica aerogel felt, which specifically comprises: applying a high-temperature adhesive to both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt, and pasting the silver-doped fiber felt on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt to obtain the composite silica aerogel felt.

[0089] In the present invention, the high-temperature adhesive refers to a class of compounds that can still achieve good bonding effects under high temperature conditions. It is a class of reagents commonly used in the prior art. Its specific examples include but are not limited to: one or more of aluminum borosilicate high-temperature adhesives, aluminum dihydrogen phosphate high-temperature adhesives and silicate high-temperature adhesives.

[0090] In the present invention, the application amount of the high temperature adhesive is preferably 1 mg / cm 2 ~10mg / cm 2 , specifically 1 mg / cm 2 , 2mg / cm 2 , 3mg / cm 2 , 4mg / cm 2 , 5mg / cm 2 , 5.5mg / cm 2 , 7mg / cm 2 , 9mg / cm 2 、10mg / cm 2 At this time, the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt and the silver-doped fiber felt have better bonding strength.

[0091] The present invention also provides the use of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt or composite silica aerogel felt in the preparation of thermal insulation materials.

[0092] The embodiments of the present invention are described in detail below. The examples of the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this area or according to the product specifications. Reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0093] Preparation Example 1

[0094] This preparation example is used to illustrate the preparation of mullite whiskers, which specifically includes:

[0095] (1) Al2(SO4)3, SiO2 and K2SO4 were mixed uniformly in a mass ratio of 543:171:10, dried in a drying oven at 80°C for 3 h, and then ball-milled at 300 r / min for 4 h to obtain a mixed powder.

[0096] (2) The mixed powder was placed in a high-temperature resistant crucible for compaction, and calcined in a nitrogen atmosphere at a heating rate of 5°C / min, a holding temperature of 1000°C, and a holding time of 5 h to obtain a sintered product.

[0097] (3) The sintered product was mixed with deionized water in a volume ratio of 1:3 and ultrasonically treated for 30 minutes. The mixture was then centrifuged at 10,000 r / min for 5 minutes, and the supernatant was removed to complete one washing process. The above washing process was repeated until the conductivity of the filtrate was close to that of pure water. The mixture was then dried at 80°C for 24 hours and passed through a 200-mesh sieve to obtain mullite whiskers.

[0098] Preparation Example 2

[0099] This preparation example adopts the method provided in Preparation Example 1 to prepare mullite whiskers, except that LiF is used instead of K2SO4 in an equal molar amount. Other conditions are the same to obtain mullite whiskers.

[0100] Example 1

[0101] This embodiment is used to illustrate the preparation of a mullite whisker-GO-ZrO2-SiO2 composite aerogel felt, which specifically includes:

[0102] S1. Preparation of silver-doped mullite fiber felt: (1) Mullite fiber felts (Zhejiang Weiye Company, product number 72) with a size of 10 cm × 10 cm × 2 cm were immersed in a 10 g / L AgNO3 solution, shaken at room temperature for 2 h, and then ultrasonically treated for 30 min to obtain AgNO3-impregnated mullite fiber felts;

[0103] (2) AgNO3-impregnated mullite fiber felt was immersed in a 100 g / L ascorbic acid solution, subjected to a reduction reaction in an oscillator at 60°C for 4 h, and then placed on a roller mill for rolling treatment until the solution residue on the felt reached 60%. The felt was dried at 80°C for 24 h to obtain a silver-doped mullite fiber felt having a silver loading of approximately 1 g.

[0104] S2. Preparation of mullite whisker-GO-ZrO2-SiO2 composite aerogel felt: (1) 44.419 g of ZrOCl28H2O was dissolved in 100 mL of anhydrous ethanol, and 8.9 mL of deionized water was added, and magnetic stirring was performed for 10 min to obtain ZrO2 sol.

[0105] (2) Take 20 mL of water glass (Shanghai McLean Biochemical Technology Co., Ltd., product number 779225, modulus 3.3-3.5) and mix it with 80 mL of deionized water, and stir it at 200 r / min for 10 minutes to obtain a silicon source aqueous solution; take 0.149 g of graphene oxide (prepared by the Hummers method, with an oxidation degree of 30%, a water content of 10%, a sheet thickness of 1 nm, and a particle size of 100 μm) and mix it with 10 mL of deionized water, stir it at 200 r / min for 4 hours, and then perform ultrasonic stripping at 250 W for 4 hours to obtain a GO dispersion; according to the added mass of GO being 5% of the theoretical mass of silica generated, take the GO dispersion and add it to the silicon source aqueous solution, and stir it at 200 r / min for 4 hours to obtain a GO-doped silicon source aqueous solution.

[0106] (3) ZrO2 sol and GO-doped SiO2 sol were mixed at a Zr:Si molar ratio of 1:1, and stirred at 200 r / min for 10 min to obtain a mixed solution. H3PO4 solution with a concentration of 6 mol / L was slowly added to the mixed solution at a stirring speed of 200 r / min until the pH value of the solution reached 1. The gelation reaction was carried out at room temperature and 200 r / min for 1 h to obtain GO-ZrO2-SiO2 sol.

[0107] (4) Ammonium polyphosphate flame retardant (Lanxiang Chemical Co., Ltd., product number 54621) was added to the GO-ZrO2-SiO2 sol at a final concentration of 0.5 wt%, and stirred at 200 r / min for 20 min to obtain a mixed sol A. Mullite whiskers provided in Preparation Example 1 were added to the mixed sol A at a final concentration of 5 wt%, and stirred at 200 r / min for 20 min to obtain a mixed sol B. Propylene oxide was added to the mixed sol B at a molar ratio of propylene oxide: (Zr + Si) of 1:1, and vigorously stirred at 400 r / min for 30 min to obtain a mixed sol C.

[0108] (5) A silver-doped mullite fiber felt with a size of 10 cm × 10 cm × 2 cm was immersed in the mixed sol C for 10 min, and then placed on a roller press for roller treatment, so that the mixed sol C was fully pressed into the interior of the fiber felt, and the excess gel on the surface of the fiber felt was removed, completing one loading treatment. The above loading treatment operation was repeated once to make the residual rate of the mixed sol C on the felt 60%, and then it was allowed to stand at room temperature for 60 min to obtain a composite aerogel felt precursor A.

[0109] (6) Anhydrous ethanol and composite aerogel felt precursor A were mixed in a volume ratio of 3:1 to completely immerse the mixture. After sealing and aging treatment at room temperature for 24 hours, the mixture was hydrothermally treated at 180°C for 4 hours. Deionized water and composite aerogel felt precursor B were mixed in a volume ratio of 1:10 and then immersed for 4 hours. The solution was removed and a washing treatment was completed. The above washing treatment operation was repeated until the pH value of the solution was 6.5 and the TDS was <50ppm to obtain composite aerogel felt precursor B.

[0110] (7) Anhydrous ethanol and composite aerogel felt precursor B were mixed in a volume ratio of 3:1, and the mixture was replaced at room temperature for 12 hours. The solution was removed to obtain composite aerogel felt precursor C.

[0111] (8) Anhydrous ethanol, trimethylsilyl chloride and n-hexane were mixed in a volume ratio of 1:1:10 to obtain a hydrophobic modification liquid, and the replacement solution and composite aerogel felt precursor C were mixed in a volume ratio of 2:1. The hydrophobic modification treatment was carried out at 40°C for 16 hours, and the hydrophobic modification liquid was replaced every 8 hours to obtain a composite aerogel felt precursor D.

[0112] (9) The composite aerogel felt precursor D was placed in a vacuum drying oven for treatment to obtain a mullite whisker-GO-ZrO2-SiO2 composite aerogel felt; wherein the vacuum drying treatment procedure includes: maintaining at 30°C for 2 h, maintaining at 50°C for 2 h, maintaining at 60°C for 3 h, and maintaining at 80°C for 3 h, and the pressure is <0.1 Pa.

[0113] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in this embodiment, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel is 11.5 g.

[0114] Example 2

[0115] This embodiment provides a composite silica aerogel felt and a preparation method thereof, referring to Figure 1 The composite silica aerogel felt includes mullite whisker-GO-ZrO2-SiO2 composite aerogel felt and silver-doped mullite fiber felt, and the silver-doped mullite fiber felt is arranged on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

[0116] The preparation of the composite silica aerogel felt specifically includes: applying 5g of aluminum borosilicate high-temperature adhesive (Rongsheng Refractory Materials Co., Ltd., item number 776512) on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in Example 1, and then pasting two pieces of silver-doped mullite fiber felt with a size of 10cm×10cm×1mm on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt, and naturally drying it to obtain a composite silica aerogel felt.

[0117] Among them, two pieces of silver-doped mullite fiber felts with a size of 10 cm×10 cm×1 mm were both prepared by the method provided in Example 1.

[0118] Example 3

[0119] The composite silica aerogel felt provided in this embodiment is basically the same as that provided in Example 2, except that, in step "S2, mullite whisker-GO-ZrO2-SiO2 composite aerogel felt", the mixing ratio of the GO dispersion and the silicon source aqueous solution is: the mass of GO added is 0.1% of the theoretical mass of the generated silica, and other conditions are the same to obtain a composite silica aerogel felt.

[0120] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in this embodiment, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel is 9.9 g.

[0121] Example 4

[0122] The composite silica aerogel felt provided in this embodiment is basically the same as that provided in Example 2, except that, in step "S2, mullite whisker-GO-ZrO2-SiO2 composite aerogel felt", the mixing ratio of the GO dispersion and the silicon source aqueous solution is: the added mass of GO is 10% of the theoretical mass of the generated silica, and other conditions are the same to obtain a composite silica aerogel felt.

[0123] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in this embodiment, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel is 12 g.

[0124] Example 5

[0125] The composite silica aerogel felt provided in this embodiment is basically the same as that provided in Example 2, except that, in step "S2, mullite whiskers-GO-ZrO2-SiO2 composite aerogel felt", the mullite whiskers provided in Preparation Example 2 are used instead of the mullite whiskers provided in Preparation Example 1, and other conditions are the same to obtain a composite silica aerogel felt.

[0126] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in this embodiment, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel is 11.3 g.

[0127] Example 6

[0128] The composite silica aerogel felt provided in this embodiment is basically the same as that provided in Example 2, except that, in step "S2, mullite whisker-GO-ZrO2-SiO2 composite aerogel felt", the ZrO2 sol and the GO-doped silicon source aqueous solution are mixed in a Zr:Si molar ratio of 1:2, and other conditions are the same to obtain a composite silica aerogel felt.

[0129] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in this embodiment, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel is 8.5 g.

[0130] Example 7

[0131] The composite silica aerogel felt provided in this embodiment is basically the same as that provided in Example 2, except that, in step "S2, mullite whisker-GO-ZrO2-SiO2 composite aerogel felt", the ZrO2 sol and the GO-doped silicon source aqueous solution are mixed in a Zr:Si molar ratio of 1:5, and other conditions are the same to obtain a composite silica aerogel felt.

[0132] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in this embodiment, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel is 6.9 g.

[0133] Example 8

[0134] The composite silica aerogel felt provided in this embodiment is basically the same as that provided in Example 2, except that, in step "S2, mullite whisker-GO-ZrO2-SiO2 composite aerogel felt", the final concentration of mullite whiskers in the mixed sol B is 1 wt %, and other conditions are the same to obtain a composite silica aerogel felt.

[0135] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in this embodiment, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel is 7.1 g.

[0136] Example 9

[0137] The composite silica aerogel felt provided in this embodiment is basically the same as that provided in Example 2, except that, in step "S2, mullite whisker-GO-ZrO2-SiO2 composite aerogel felt", the final concentration of mullite whiskers in the mixed sol B is 10 wt %, and other conditions are the same to obtain a composite silica aerogel felt.

[0138] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in this embodiment, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel is 14.7 g.

[0139] Example 10

[0140] The composite silica aerogel felt provided in this embodiment is basically the same as that provided in Example 2, except that, in step "S1, silver-doped mullite fiber felt", basalt fiber felt of equal size (Zhejiang Weiye Company, item number 608) is used instead of mullite fiber felt, and other conditions are the same to obtain a composite silica aerogel felt.

[0141] In the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt provided in this embodiment, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel is 11.7 g.

[0142] Comparative Example 1

[0143] This comparative example uses the method provided in Example 1 to prepare mullite whisker / GO / ZrO2 / SiO2 composite aerogel felt, except that step "S1, preparation of silver-doped mullite fiber felt" is not included, that is, in step "S2, mullite whisker-GO-ZrO2-SiO2 composite aerogel felt", a mullite fiber felt with a size of 10 cm×10 cm×2 cm is used instead of the silver-doped mullite fiber felt, and other conditions are the same to obtain mullite whisker / GO / ZrO2 / SiO2 composite aerogel felt.

[0144] Comparative Example 2

[0145] This comparative example uses the method provided in Example 1 to prepare mullite whisker / GO / SiO2 composite aerogel felt, except that in step "S2, mullite whisker-GO-ZrO2-SiO2 composite aerogel felt", an aqueous silicon source solution doped with GO in an equimolar addition amount (in terms of Si and Zr) is used instead of the ZrO2 sol, that is, ZrO2 is not introduced into the material, and other conditions are the same to obtain a mullite whisker / GO / SiO2 composite aerogel felt.

[0146] Comparative Example 3

[0147] This comparative example adopts the method provided in Example 1 to prepare GO / ZrO2 / SiO2 composite aerogel felt, except that, in step "S2, mullite whiskers / GO / ZrO2 / SiO2 composite aerogel felt", an equal mass of mixed sol A is used instead of the mullite whiskers provided in Preparation Example 1, that is, mullite whiskers are not introduced into the material. Other conditions are the same, and mullite whiskers / GO / ZrO2 / SiO2 composite aerogel felt is obtained.

[0148] Comparative Example 4

[0149] This comparative example uses the method provided in Example 1 to prepare mullite whisker / ZrO2 / SiO2 composite aerogel felt, except that in step "S2, mullite whisker / GO / ZrO2 / SiO2 composite aerogel felt", an equal volume of silicon source aqueous solution is used instead of the GO dispersion, that is, GO is not introduced into the material, and other conditions are the same to obtain mullite whisker / GO / ZrO2 / SiO2 composite aerogel felt.

[0150] Test Case

[0151] This test example is used to illustrate the relevant properties of the mullite whisker / GO / ZrO2 / SiO2 composite aerogel felt and the composite silica aerogel felt provided in the above examples, and the comparative example is used as a control. The test method refers to "GB / T34336-2017 Nanoporous Aerogel Composite Insulation Products" and "GB / T20944.3-2008 Evaluation of Antibacterial Properties of Textiles Part 3: Oscillation Method", and the results are shown in Table 1.

[0152] Table 1.

[0153]

[0154]

[0155] It can be seen from the results shown in Table 1 that, compared with comparative examples 1 to 4, the thermal conductivity of the mullite whisker / GO / ZrO2 / SiO2 composite aerogel felt and the composite silica aerogel felt provided in Examples 1 to 10 of the present invention meet the use requirements of ultra-high temperature environments above 650°C, the transverse tensile strength and longitudinal tensile strength are large, the flame retardant grades are all A1 and above, and they have excellent thermal insulation performance, flame retardant performance and mechanical properties; and the vibration mass loss rates of the mullite whisker / GO / ZrO2 / SiO2 composite aerogel felt and the composite silica aerogel felt are both lower than 1%, indicating that the mullite whisker-GO-ZrO2-SiO2 composite aerogel loaded thereon has excellent bonding strength with the fiber felt substrate, so that the structure and performance of the product have good stability in actual use, and it is a highly promising thermal insulation material, especially in ultra-high temperature environments above 650°C. It has great prospects for use.

[0156] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A mullite whisker-GO-ZrO2-SiO2 composite aerogel felt, characterized in that: The mullite whisker-GO-ZrO2-SiO2 composite aerogel felt comprises a silver-doped fiber felt and a mullite whisker-GO-ZrO2-SiO2 composite aerogel, and the mullite whisker-GO-ZrO2-SiO2 composite aerogel is loaded on the silver-doped fiber felt.

2. The mullite whisker-GO-ZrO2-SiO2 composite aerogel felt according to claim 1, characterized in that: The silver loading on the silver-doped fiber felt is 0.5 mg / cm 3 ~150mg / cm 3 ; Optionally, the loading amount of the mullite whisker-GO-ZrO2-SiO2 composite aerogel on the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt is 5 mg / cm 3 ~400mg / cm 3 .

3. The method for preparing the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt according to claim 1 or 2, characterized in that: The preparation method comprises: S1, taking a silver ion aqueous solution to impregnate a high-temperature resistant fiber felt to obtain a silver ion-impregnated fiber felt, taking a reducing agent solution to perform a reduction reaction on the silver ion-impregnated fiber felt to obtain the silver-doped fiber felt; S2. Mix ZrO2 sol, graphene oxide dispersed aqueous solution and silicon source aqueous solution to obtain a mixed solution; perform gelation reaction on the mixed solution to obtain GO-ZrO2-SiO2 sol; mix mullite whiskers with GO-ZrO2-SiO2 sol to obtain a mixed sol; perform loading treatment on silver-doped fiber felt with the mixed sol to obtain a composite aerogel felt precursor; perform aging treatment, solvent replacement treatment, hydrophobic modification treatment and drying treatment on the composite aerogel felt precursor to obtain the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

4. The method for preparing the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt according to claim 3, characterized in that: In step S1, the concentration of silver ions in the silver ion aqueous solution is 0.01 mol / L to 1 mol / L; Optionally, the high temperature resistant fiber felt includes one or more of mullite fiber felt, basalt fiber felt and aluminum silicate fiber felt; Optionally, the impregnation treatment method comprises: immersing the high-temperature resistant fiber felt in a silver ion aqueous solution, performing an oscillation treatment for 60 minutes to 300 minutes and an ultrasonic treatment for 1 minute to 120 minutes to obtain the silver ion-impregnated fiber felt; Optionally, the reducing agent solution comprises one or more of ascorbic acid, sodium citrate and glucose; Optionally, the concentration of the reducing agent in the reducing agent solution is 0.01 mol / L to 6 mol / L; Optionally, the reduction reaction temperature is 50° C. to 100° C., and the time is 1 h to 6 h.

5. The method for preparing the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt according to claim 3, characterized in that: In step S2, in the graphene oxide dispersed aqueous solution, the oxidation degree of graphene oxide is 10% to 50%, the thickness of the flakes is 0.1 nm to 3 nm, and the particle size is 50 μm to 300 μm; Optionally, the addition ratio of the ZrO2 sol and the silicon source aqueous solution is 1:(1-5) based on the added molar ratio of Zr to Si, and the addition amount of the graphene oxide dispersed aqueous solution is 0.1% to 10% based on the mass of graphene oxide to the mass of theoretically generated silicon dioxide; Optionally, the gelation reaction method includes: slowly adding an acid solution to the mixed solution under stirring until the pH value reaches 1 to 5, and performing a gelation reaction under stirring for 0.1 h to 5 h to obtain the GO-ZrO2-SiO2 sol; Optionally, the acid solution includes one or more of hydrochloric acid, sulfuric acid and phosphoric acid; Optionally, the preparation method of the mullite whisker comprises: mixing an aluminum source compound, silicon dioxide and a mineralizer, and calcining the mixture to obtain the mullite whisker; Optionally, in the preparation of the mullite whiskers, the aluminum source compound includes one or more of Al2(SO4)3, Al(NO3)3 and AlCl3; Optionally, in the preparation of the mullite whiskers, the mineralizer includes one or more of K2SO4, NaCl, KCl, Na2SO4 and LiF; Optionally, in the preparation of the mullite whiskers, the molar ratio of Al to Si in the aluminum source compound and silicon dioxide is (1-5):1, and the mass ratio of the mineralizer to the sum of the aluminum source compound and silicon dioxide is (1-5):1; Optionally, in the preparation of the mullite whiskers, the heating rate of the calcination treatment is 5°C / min to 10°C / min, the holding temperature is 600°C to 1200°C, and the holding time is 1h to 8h; Optionally, the concentration of mullite whiskers in the mixed sol is 1 wt% to 10 wt%; Optionally, a flame retardant is added to the mixed sol, and the flame retardant includes one or more of a phosphorus-based inorganic flame retardant, a borate-based inorganic flame retardant, a halogen-based organic flame retardant, and a phosphorus-nitrogen-based organic flame retardant; Optionally, the concentration of the flame retardant in the mixed sol is 0.1 wt% to 10 wt%; Optionally, a gel accelerator is added to the mixed sol, and the gel accelerator includes one or more of epoxybutene, glycidol, propylene oxide and polyacrylic acid; Optionally, in the mixed sol, the molar ratio of the gel accelerator to the sum of Zr—Si is 1:(1-5).

6. The method for preparing the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt according to claim 3, characterized in that: In step S2, the loading treatment method includes: taking the silver-doped fiber felt and immersing it in the mixed sol for 1 minute to 30 minutes, and then performing a roller pressing treatment to make the rolling rate of the mixed sol on the silver-doped fiber felt 50% to 70%, taking the silver-doped fiber felt loaded with the mixed sol and performing a static treatment for 20 minutes to 120 minutes to obtain the composite aerogel felt precursor.

7. The method for preparing the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt according to claim 3, characterized in that: In step S2, the aging treatment method includes: mixing an aging agent with the composite aerogel felt precursor, performing a sealing aging treatment at 15° C. to 35° C. for 12 h to 48 h, and performing a hydrothermal treatment at 120° C. to 200° C. for 12 h to 48 h; Optionally, the aging agent includes one or more of ethanol, toluene, acetone and the mixed solution; Optionally, the volume ratio of the aging agent to the composite aerogel felt precursor is (1-5):1; Optionally, the solvent replacement treatment method comprises: mixing ethanol with the composite aerogel felt precursor that has undergone the aging treatment, performing replacement at 15° C. to 35° C. for 12 to 96 hours, and replacing the ethanol every 12 to 24 hours; Optionally, the volume ratio of the ethanol to the composite aerogel felt precursor that has undergone the aging treatment is (1-10):1; Optionally, the hydrophobic modification method comprises: mixing a hydrophobic modification liquid with the composite aerogel felt precursor that has undergone the solvent replacement treatment, performing a hydrophobic modification treatment at 10° C. to 50° C. for 1 hour to 40 hours, and replacing the hydrophobic modification liquid every 1 hour to 10 hours; Optionally, the drying method includes: taking the composite aerogel felt precursor that has undergone the hydrophobic modification treatment and performing a first vacuum drying treatment at 25°C to 35°C for 1h to 3h, performing a second vacuum drying treatment at 45°C to 55°C for 1h to 3h, performing a third vacuum drying treatment at 55°C to 65°C for 2h to 4h, and performing a fourth vacuum drying treatment at 75°C to 85°C for 2h to 4h to obtain the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

8. A composite silica aerogel felt, characterized in that: The composite silica aerogel felt comprises the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt and a silver-doped fiber felt according to claim 1 or 2, and the silver-doped fiber felt is arranged on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt.

9. The method for preparing the composite silica aerogel felt according to claim 8, characterized in that: The preparation method comprises: applying a high-temperature adhesive to both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt, and pasting the silver-doped fiber felt on both sides of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt to obtain the composite silica aerogel felt.

10. Use of the mullite whisker-GO-ZrO2-SiO2 composite aerogel felt according to claim 1 or 2 or the composite silica aerogel felt according to claim 9 in the preparation of thermal insulation materials.

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