Foam reinforced silicon dioxide aerogel composite material and preparation method thereof

Abstract

The invention relates to the technical field of composite materials, in particular to a foam reinforced silicon dioxide aerogel composite material and a preparation method thereof. The preparation method comprises the following steps: firstly, preparing fumed silica slurry, adding an opacifying agent, a silane coupling agent and the like, pouring the slurry into foam, filling foam pores, then carrying out a sol-gel process, and carrying out drying in various forms after gelatinization to obtain the aerogel composite material which can continue surface ceramization. The composite material is composed of foam, fumed silica, aerogel and an opacifying agent, and has excellent mechanical compressive strength, tensile strength, anti-vibration and anti-bending capability, durability, compressibility and fireproof and flame-retardant performance while keeping light weight, heat preservation and heat insulation performance and sound absorption and sound insulation performance. The aerogel composite material is good in flatness and stiffness and can be cut, carved and processed into a complex profiling structure, the splicing rough edge heat bridge effect of a traditional glass fiber aerogel material is reduced, and the heat insulation and energy saving efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and particularly relates to a foam-reinforced silica aerogel composite material and a preparation method thereof. Background Art

[0002] As a nanoscale porous material, silica aerogel has become a favorite in many fields, including sound insulation and noise reduction, building energy conservation, and the demanding aerospace field, due to its high specific surface area, rich pore structure, extremely low density, good thermal insulation performance, and low refractive index and dielectric constant. The light texture, high porosity and excellent thermal insulation ability of silica aerogel not only make it an ideal choice for thermal insulation and sound absorption, but also highlight great application potential in pipeline insulation and promoting the development of green buildings. However, in practical applications, silica aerogel is still limited by limited thermal insulation and sound absorption performance, poor mechanical properties and high cost, especially for aerospace applications that require high strength and durability.

[0003] Glass fiber, carbon fiber, silicon carbide fiber reinforced aerogel is a composite material that introduces glass fiber into the aerogel matrix to improve its mechanical properties and maintain other excellent properties (such as low density, high porosity, excellent thermal insulation, etc.). This reinforcement method aims to overcome the shortcomings of aerogel itself, which is fragile and has low mechanical strength. However, due to the coarse fibers and large fiber gaps, the particles of aerogel are only supported by van der Waals forces during suspension. During mechanical vibration and thermal fatigue, it is easy to lose powder and collapse, resulting in larger pores, increasing thermal conductivity and reducing insulation effect. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a foam-reinforced silica aerogel composite material and a preparation method thereof. The foam-reinforced silica aerogel composite material provided by the present invention has excellent thermal insulation performance, sound absorption and sound insulation performance, mechanical strength and durability.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a foam-reinforced silica aerogel composite material, which is composed of foam, fumed silica, aerogel and a sunscreen, wherein the total mass of the fumed silica and the sunscreen is 50-98% of the mass of the foam-reinforced silica aerogel composite material, and the density of the foam-reinforced silica aerogel composite material is 10-200 kg / m 3 , thermal conductivity is 0.021~0.029W / mK, and combustion grade is V-0~V-1.

[0007] Preferably, the foam is one or more of melamine foam, polyurethane sponge, polystyrene foam, phenolic foam and polyimide foam; the density of the foam is 5 to 20 kg / m 3 , the porosity is 90.4~99.7%.

[0008] Preferably, the sunscreen includes one or more of carbon black, graphene, carbon nanotubes, vanadium oxide, zirconium oxide and carbide; the carbide includes one or more of silicon carbide nanopowder, silicon carbide nanowire, boron carbide powder and boron carbide nanowire.

[0009] The present invention also provides a method for preparing the foam-reinforced silica aerogel composite material described in the above technical solution, comprising the following steps in order:

[0010] (1) mixing fumed silica, a sunscreen, a silane coupling agent, an organic acid and water to obtain a fumed silica slurry;

[0011] (2) placing the foam in the fumed silica slurry for impregnation to obtain an impregnated foam;

[0012] (3) Using an ammonia solution to adjust the pH value of the silica slurry in the impregnated foam to neutral, allowing it to stand for a sol-gel reaction, and drying to obtain the foam-reinforced silica aerogel composite material.

[0013] The present invention provides a foam-reinforced silica aerogel composite material, which is composed of foam, fumed silica, aerogel and a sunscreen, wherein the total mass of the fumed silica and the sunscreen is 50-98% of the mass of the foam-reinforced silica aerogel composite material, and the density of the foam-reinforced silica aerogel composite material is 10-200 kg / m 3 , thermal conductivity is 0.021-0.029W / mK, and combustion grade is V-0-V-1. The introduction of foam provided by the present invention not only enhances the tear strength of silica aerogel, improves its durability, but also improves its compressibility and fire retardant properties, so that the foam-reinforced silica aerogel composite material has the advantages of good flatness, good stiffness, smooth cutting edges, and can be cut and carved into complex contoured structures while maintaining light weight, thermal insulation and sound absorption and sound insulation properties, effectively reducing the splicing thermal bridge and rough edge thermal bridge effect of traditional glass fiber felt aerogel materials, and improving thermal insulation and energy-saving efficiency. DETAILED DESCRIPTION

[0014] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0015] Example 1 Polyurethane sponge in reinforced silica aerogel insulation material and preparation method thereof

[0016] Adding a mixture of fumed silica powder, deionized water, oxalic acid, silane coupling agent KH-550, sunscreen graphene and vanadium oxide powder in a mass ratio of 20:174:4:2:2 into a ball mill, wherein the mass ratio of graphene to vanadium oxide powder is 1:5, to obtain fumed silica slurry;

[0017] The cut size is 1200mm×600mm×20mm and the density is 12kg / m 3 A polyurethane sponge with a porosity of 95% is placed in a mold, and the above-mentioned fumed silica slurry is poured into the mold cavity, and vibration is performed to promote the slurry to completely penetrate into the polyurethane sponge to obtain a polyurethane sponge loaded with fumed silica slurry; ammonia water is added to adjust the pH value to 7, and the mixture is allowed to stand for 1 hour for a sol-gel reaction to form a gel; and the polyurethane sponge is dried by supercritical carbon dioxide to obtain a polyurethane sponge reinforced silica aerogel composite material.

[0018] The density of the polyurethane sponge reinforced silica aerogel composite material prepared in this example is 128 kg / m 3 The room temperature thermal conductivity is 0.022W / m·K, the compressive strength at a strain of 60% is 152KPa, it can work for a long time in an oxidizing environment below 100°C, and has a V-1 flame retardant effect.

[0019] Example 2 Melamine foam reinforced silica aerogel insulation material and preparation method thereof

[0020] Add fumed silica powder, deionized water, oxalic acid, silane coupling agent KH-560 and carbon black sunscreen in a mass ratio of 10:187:2:1:1 into a ball mill, and perform ball milling and dispersion for 12 hours to obtain fumed silica slurry;

[0021] The outer diameter is 200mm, the inner diameter is 160mm, the length is 500mm, and the density is 8kg / m 3 , a melamine foam with a porosity of 95% is placed in a mold cavity, the above-mentioned fumed silica slurry is poured into the mold cavity, and after vibration, the mold is placed in a vacuum tank, and evacuated to negative pressure to remove the gas in the slurry. The surface color of the melamine foam is uniform. After standing for 1 hour, the mold is taken out from the vacuum tank to obtain the melamine foam loaded with fumed silica slurry; a mixture of 1 mol / L ammonia water and anhydrous ethanol in a mass ratio of 1:15 is dripped onto the melamine foam loaded with fumed silica slurry, ammonia water is added to adjust the pH value of the fumed silica slurry in the melamine foam to 7, and it is allowed to stand for 1 hour to form a gel after the sol-gel reaction, and then freeze-dried to obtain melamine foam reinforced silica aerogel composite pipe fittings.

[0022] The density of the melamine foam reinforced silica aerogel composite pipe prepared in this example is 78 kg / m 3 The room temperature thermal conductivity is 0.026W / m·K, and the compressive strength at a strain of 60% is 125KPa. It can be put on thermal pipes below 220°C and serve for a long time in the atmospheric environment. It has a V-0 flame retardant effect.

[0023] Example 3 Polyimide foam reinforced silica aerogel insulation material and preparation method thereof

[0024] Add fumed silica powder, deionized water, oxalic acid, silane coupling agent KH-570 and sunscreen in a mass ratio of 30:161:6:3:4 into a ball mill, where the sunscreen is a mixture of silicon carbide nanopowder and boron carbide nanowires in a mass ratio of 1:1, and ball mill for 12 hours to obtain fumed silica slurry;

[0025] The cut height is 400mm, the opening diameter is 800mm, and the density is 20kg / m 3 , a polyimide cone foam with a porosity of 95% is placed in a mold cavity, the above-mentioned fumed silica slurry is poured into the mold cavity, and the fumed silica slurry is infiltrated into the polyimide foam by ultrasonic dispersion to obtain a polyimide foam loaded with fumed silica slurry; the pH value of the fumed silica slurry in the polyimide foam is adjusted to 7 by ammonia water, and a gel is formed by standing for a certain period of time; the polyimide gel foam is placed in a microwave oven to dry. Then the outer surface of the cone foam is immersed in a silica sol solution, dried at room temperature, and ceramicized by infrared laser surface heating to obtain a polyimide foam reinforced silica aerogel composite cone head cap with excellent heat insulation effect.

[0026] The density of the polyimide foam reinforced silica aerogel composite cone head cap prepared in this example is 163 kg / m 3 The thermal conductivity at room temperature is 0.029W / m·K, the thermal conductivity at 300℃ is 0.035W / mK, the compressive strength at a strain of 60% is 348KPa, it can work for a long time below 300℃, and has a V-0 flame retardant effect.

[0027] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A foam-reinforced silica aerogel composite material, characterized in that: The foam reinforced silica aerogel composite material is composed of foam, fumed silica, aerogel and sunscreen, wherein the total mass of the fumed silica and the sunscreen is 50-98% of the mass of the foam reinforced silica aerogel composite material, and the density of the foam reinforced silica aerogel composite material is 10-200 kg / m 3 , thermal conductivity is 0.021~0.029W / mK, and combustion grade is V-0~V-1.

2. The foam-reinforced silica aerogel composite material according to claim 1, characterized in that: The foam is one or more of melamine foam, polyurethane sponge, polystyrene foam, phenolic foam and polyimide foam; the density of the foam is 5-20 kg / m 3 , the porosity is 90.4~99.7%.

3. The foam-reinforced silica aerogel composite material according to claim 1, characterized in that: The sunscreen includes one or more of carbon black, graphene, carbon nanotubes, vanadium oxide, zirconium oxide and carbide; the carbide includes one or more of silicon carbide nanopowder, silicon carbide nanowire, boron carbide powder and boron carbide nanowire.

4. The method for preparing the foam-reinforced silica aerogel composite material according to any one of claims 1 to 3, characterized in that: The steps include the following sequence: (1) mixing fumed silica, a sunscreen, a silane coupling agent, an organic acid and water to obtain a fumed silica slurry; (2) placing the foam in the fumed silica slurry for impregnation to obtain an impregnated foam; (3) Using an ammonia solution to adjust the pH value of the silica slurry in the impregnated foam to neutral, allowing it to stand for a sol-gel reaction, and drying to obtain the foam-reinforced silica aerogel composite material.