A foam-reinforced silica aerogel composite material and its preparation method

Abstract

This invention relates to the field of composite material technology, specifically to a foam-reinforced silica aerogel composite material and its preparation method. The invention first prepares a fumed silica slurry, adds a light-blocking agent and a silane coupling agent, and then pours the slurry into foam to fill the foam pores. A sol-gel process is then carried out, followed by various drying methods after gelation to obtain the aerogel composite material, which can be further surface-ceramized. This composite material consists of foam, fumed silica, aerogel, and a light-blocking agent. While maintaining lightweight, thermal insulation, and sound absorption properties, it also possesses excellent compressive strength, tensile strength, vibration resistance, bending resistance, durability, compressibility, and fire retardant properties. This aerogel composite material exhibits good flatness and stiffness, and can be cut and sculpted into complex contoured structures, reducing the thermal bridging effect of rough edges in traditional glass fiber aerogel materials and improving thermal insulation and energy-saving efficiency.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a foam-reinforced silica aerogel composite material and its preparation method. Background Technology

[0002] Silica aerogel, as a nanoscale porous material, has become a favorite in many fields due to its high specific surface area, abundant pore structure, extremely low density, good thermal insulation properties, and low refractive index and dielectric constant. These applications include sound insulation and noise reduction, building energy conservation, and the demanding aerospace industry. The lightweight texture, high porosity, and excellent thermal insulation capabilities of silica aerogel not only make it an ideal choice for thermal insulation and sound absorption but also demonstrate its great application potential in pipe insulation and promoting green building development. However, in practical applications, silica aerogel is still limited by its limited thermal insulation and sound absorption properties, poor mechanical properties, and high cost, especially for aerospace applications requiring high strength and durability.

[0003] Glass fiber, carbon fiber, and silicon carbide fiber reinforced aerogels are composite materials that improve mechanical properties while maintaining other excellent properties (such as low density, high porosity, and excellent thermal insulation) by introducing glass fibers into the aerogel matrix. This reinforcement method aims to overcome the inherent fragility and low mechanical strength of aerogels. However, due to the relatively coarse fibers and large inter-fiber gaps, the particles in the aerogel are supported only by van der Waals forces during suspension. Under mechanical vibration and thermal fatigue, they are prone to powdering and collapse, resulting in even larger pores, increased thermal conductivity, and reduced insulation performance. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a foam-reinforced silica aerogel composite material and its preparation method. 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] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a foam-reinforced silica aerogel composite material, comprising foam, fumed silica, aerogel, and a light-blocking agent. The total mass of the fumed silica and the light-blocking agent 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 / m³. 3 It has a thermal conductivity of 0.021 to 0.029 W / mK and a combustion rating of V-0 to V-1.

[0007] Preferably, the foam is one or more selected from melamine foam, polyurethane foam, polystyrene foam, phenolic foam, and polyimide foam; the density of the foam is 5–20 kg / m³. 3 The porosity is 90.4%–99.7%.

[0008] Preferably, the light-blocking agent includes one or more of carbon black, graphene, carbon nanotubes, vanadium oxide, zirconium oxide, and carbides; the carbides include one or more of silicon carbide nanoparticles, silicon carbide nanowires, boron carbide powder, and boron carbide nanowires.

[0009] This invention also provides a method for preparing the foam-reinforced silica aerogel composite material described above, comprising the following steps in sequence:

[0010] (1) Mix fumed silica, light-blocking agent, silane coupling agent, organic acid and water to obtain fumed silica slurry;

[0011] (2) The foam is placed in the fumed silica slurry for impregnation to obtain the impregnated foam;

[0012] (3) The pH value of the silica slurry in the impregnated foam is adjusted to neutral by using an ammonia solution, and the sol-gel reaction is carried out by standing. After drying, the foam-reinforced silica aerogel composite material is obtained.

[0013] This invention provides a foam-reinforced silica aerogel composite material, comprising foam, fumed silica, aerogel, and a light-blocking agent. The total mass of the fumed silica and the light-blocking agent 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 / m³. 3 The thermal conductivity is 0.021–0.029 W / mK, and the flammability rating is V-0–V-1. The introduction of foam in this invention not only enhances the tear strength and durability of silica aerogel, but also improves its compressibility and fire-retardant properties. This allows the foam-reinforced silica aerogel composite material to maintain its lightweight, thermal insulation, and sound absorption properties, while also possessing advantages such as good flatness, stiffness, smooth cut edges, and the ability to be cut and sculpted into complex contoured structures. This effectively reduces the splicing thermal bridges and rough edge thermal bridge effects of traditional glass fiber felt aerogel materials, improving thermal insulation and energy-saving efficiency. Detailed Implementation

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

[0015] Example 1: Polyurethane foam in reinforced silica aerogel insulation materials and its preparation method

[0016] A mixture of fumed silica powder, deionized water, oxalic acid, silane coupling agent KH-550, light-shielding agent graphene, and vanadium oxide powder in a mass ratio of 20:174:4:2:2 was added to a ball mill jar, wherein the mass ratio of graphene to vanadium oxide powder was 1:5, to obtain a fumed silica slurry.

[0017] The cut dimensions are 1200mm×600mm×20mm, and the density is 12kg / m³. 3 A polyurethane sponge with a porosity of 95% was placed in a mold, and the above-mentioned fumed silica slurry was poured into the mold cavity. Vibration was used to promote the complete penetration of the slurry into the polyurethane sponge, resulting in a polyurethane sponge loaded with fumed silica slurry. Ammonia was added to adjust the pH value to 7, and the mixture was allowed to stand for 1 hour to carry out a sol-gel reaction to form a gel. The gel was then dried by supercritical carbon dioxide to obtain a polyurethane sponge-reinforced silica aerogel composite material.

[0018] The density of the polyurethane foam-reinforced silica aerogel composite material prepared in this embodiment is 128 kg / m³. 3 It has a thermal conductivity of 0.022 W / m·K at room temperature, a compressive strength of 152 kPa at 60% strain, can work for a long time in oxidizing environments below 100℃, and has a V-1 level flame retardant effect.

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

[0020] Add fumed silica powder, deionized water, oxalic acid, silane coupling agent KH-560 and carbon black opacifier in a ball mill jar with a mass ratio of 10:187:2:1:1, and disperse by ball milling for 12 hours to obtain fumed silica slurry.

[0021] A container with an outer diameter of 200mm, an inner diameter of 160mm, a length of 500mm, and a density of 8kg / m³ is used. 3 Melamine foam with a porosity of 95% was placed in a mold cavity, and the above-mentioned fumed silica slurry was poured into the mold cavity. After vibration, the mold was placed in a vacuum tank, and a vacuum was drawn to negative pressure to remove the gas in the slurry. The surface of the melamine foam was uniform in color. After standing for 1 hour, the mold was removed from the vacuum tank to obtain melamine foam loaded with fumed silica slurry. A mixture of 1 mol / L ammonia water and anhydrous ethanol at a mass ratio of 1:15 was added dropwise to the melamine foam loaded with fumed silica slurry. Ammonia water was added to adjust the pH value of the fumed silica slurry in the melamine foam to 7. After standing for 1 hour, a gel was formed after the sol-gel reaction. Then, it was freeze-dried to obtain melamine foam reinforced silica aerogel composite pipe fitting.

[0022] The melamine foam-reinforced silica aerogel composite pipe fitting prepared in this embodiment has a density of 78 kg / m³. 3 It has a room temperature thermal conductivity of 0.026 W / m·K, a compressive strength of 125 kPa at 60% strain, can be fitted onto thermal pipelines below 220℃, can be used for long-term service in atmospheric environments, and has a V-0 flame retardant rating.

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

[0024] Fumed silica powder, deionized water, oxalic acid, silane coupling agent KH-570, and a light-blocking agent with a mass ratio of 30:161:6:3:4 were added to a ball milling jar. The light-blocking agent was a mixture of silicon carbide nanopowder and boron carbide nanowires with a mass ratio of 1:1. The mixture was ball-milled and dispersed for 12 hours to obtain fumed silica slurry.

[0025] Cut the material to a height of 400mm, an opening diameter of 800mm, and a density of 20kg / m³. 3 A polyimide cone-shaped foam with a porosity of 95% was placed in a mold cavity. The aforementioned fumed silica slurry was then poured into the mold cavity, and ultrasonic dispersion was used to impregnate the polyimide foam with the fumed silica slurry, resulting in a polyimide foam loaded with fumed silica slurry. The pH of the fumed silica slurry in the polyimide foam was adjusted to 7 using ammonia water, and the foam was allowed to stand for a certain period to form a gel. The polyimide gel foam was then dried in a microwave oven. The outer surface of the cone-shaped foam was then immersed in a silica sol solution, dried at room temperature, and then ceramicized by infrared laser surface heating, resulting in a polyimide foam-reinforced silica aerogel composite cone cap with excellent heat insulation properties.

[0026] The polyimide foam-reinforced silica aerogel composite cone cap prepared in this embodiment has a density of 163 kg / m³. 3 It has a thermal conductivity of 0.029 W / m·K at room temperature and 0.035 W / m·K at 300℃. Its compressive strength at 60% strain is 348 kPa. It can work for a long time below 300℃ and has a V-0 flame retardant rating.

[0027] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, 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 composite material is composed of foam, fumed silica, aerogel, and a light-blocking agent. The total mass of the fumed silica and the light-blocking agent 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 / m³. 3 The thermal conductivity is 0.021~0.029 W / mK, and the combustion rating is V-0~V-1; The foam is one or more of melamine foam, polyurethane foam, polystyrene foam, phenolic foam, and polyimide foam; the porosity of the foam is 90.4-99.7%; The light-blocking agent includes one or more of carbon black, graphene, carbon nanotubes, vanadium oxide, zirconium oxide, and carbides; the carbides include one or more of silicon carbide nanopowder, silicon carbide nanowires, boron carbide powder, and boron carbide nanowires. The preparation method of the foam-reinforced silica aerogel composite material includes the following steps in sequence: (1) Mix fumed silica, light-blocking agent, silane coupling agent, organic acid and water to obtain fumed silica slurry; (2) The foam is placed in the fumed silica slurry for impregnation to obtain the impregnated foam; (3) The pH value of the silica slurry in the impregnated foam is adjusted to neutral by using an ammonia solution, and the sol-gel reaction is carried out by standing. After drying, the foam-reinforced silica aerogel composite material is obtained.

2. The foam-reinforced silica aerogel composite material according to claim 1, characterized in that, The density of the foam is 5~20 kg / m³. 3 .

3. The method for preparing the foam-reinforced silica aerogel composite material according to any one of claims 1 to 2, characterized in that, The steps include the following sequence: (1) Mix fumed silica, light-blocking agent, silane coupling agent, organic acid and water to obtain fumed silica slurry; (2) The foam is placed in the fumed silica slurry for impregnation to obtain the impregnated foam; (3) The pH value of the silica slurry in the impregnated foam is adjusted to neutral by using an ammonia solution, and the sol-gel reaction is carried out by standing. After drying, the foam-reinforced silica aerogel composite material is obtained.