Alkene ceramic aerogel composite glass fiber mat as well as preparation method and application thereof

Abstract

The invention discloses an alkene ceramic aerogel composite glass fiber mat as well as a preparation method and application thereof. The alkene ceramic aerogel composite glass fiber mat formed by interweaving a reduced graphene oxide network and silicon dioxide ceramic is formed in situ in a glass fiber skeleton. The method solves the problem that the high-performance alkene ceramic aerogel and the flexible glass fiber matrix are difficult to firmly compound. According to the prepared composite felt, on the premise that the original flexibility and tailorability of the glass fiber felt are completely reserved, the normal-temperature heat conductivity coefficient is remarkably reduced to 12 mW / (m.K)-20 mW / (m.K), and the composite felt has excellent high-temperature stability and can be widely applied to the field of heat insulation in extreme environments such as aerospace heat protection and high-temperature industrial furnace heat preservation.

Description

Technical Field

[0001] This invention relates to the field of nano-high temperature insulation materials technology, specifically to an olefin-ceramic aerogel composite glass fiber mat, its preparation method, and its application. Background Technology

[0002] With the rapid development of aerospace, new energy, and high-temperature industries, higher requirements are being placed on thermal insulation materials: they must not only operate stably at high temperatures for extended periods, but also possess high strength, large dimensions (or scalable formability), and excellent thermal insulation performance. However, materials that achieve all three are extremely difficult to create.

[0003] Currently widely used traditional insulation materials such as fiberglass and ceramic fiber mats, while lightweight, easy to process, and low in cost, rely on the low thermal conductivity of still air within micron-sized pores for insulation. These materials typically have a thermal conductivity of 25 mW / (m·K)–35 mW / (m·K) at room temperature, limiting the potential for performance improvement. More importantly, as temperature rises, gas-phase heat transfer and thermal radiation significantly increase, leading to a substantial decrease in insulation effectiveness. Improving performance by increasing density or thickness sacrifices lightweight design and flexibility, making it difficult to meet the comprehensive performance requirements of modern engineering projects.

[0004] Aerogels, especially "graphene / graphene oxide aerogels" composed of inorganic ceramics such as silica at the nanoscale, exhibit extremely low thermal conductivity and good thermal stability due to their unique nanoporous structure, and are regarded as the hope for breaking through the bottlenecks of traditional thermal insulation materials. However, the problem is that high-performance graphene-ceramic aerogels are often brittle, small, and difficult to mold, making them difficult to use directly in large, irregularly shaped, or flexible engineering components.

[0005] Existing composite methods also have obvious drawbacks. For example, simply mixing aerogel powder into the fiber matrix can easily lead to uneven distribution, weak bonding, and easy detachment during use. On the other hand, using the sol-gel method to generate aerogel in situ inside the fiber is a complex and time-consuming process. The material is also prone to cracking and shrinkage during the drying process, and the resulting material is rigid and loses its original flexibility, making it unsuitable for the installation and use requirements of existing flexible thermal insulation systems.

[0006] Therefore, how to firmly and uniformly introduce the super thermal insulation capability of olefin-ceramic aerogel while retaining the good mechanical properties and engineering processability of flexible fiber substrate, and ultimately obtain a composite material that is both strong and tough, can be scaled up, and is truly thermally insulating, has become the core problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the problem of existing thermal insulation materials simultaneously possessing high strength, large size, and excellent thermal insulation performance, this invention proposes an olefin-ceramic aerogel composite glass fiber mat, its preparation method, and its applications. This invention constructs a continuous olefin-ceramic aerogel network in situ within the skeleton of the glass fiber mat, firmly embedding and anchoring an olefin-ceramic composite phase (composed of a three-dimensional network of reduced graphene oxide and a silica ceramic phase) with a nanoporous structure and excellent thermal stability within the fiber network. This strategy fundamentally differs from traditional physical mixing or easily cracked and brittle in-situ growth methods, achieving highly efficient integrated integration of the nano-insulating phase and the macroscopic flexible matrix.

[0008] This method significantly improves the thermal insulation performance of the material while fully preserving the original flexibility, processability, and large-size molding capability of glass fiber felt. The resulting composite felt has a thermal conductivity as low as 12 mW / (m·K), which is far superior to that of traditional fiber felt.

[0009] Specifically, the method provided by the present invention includes the following steps: (1) Preparation of precursor solution: Mix the aqueous dispersion of graphene oxide with the aqueous solution of sodium silicate to obtain the impregnated precursor solution, wherein the mass ratio of graphene oxide to sodium silicate is not greater than 4:1; (2) Vacuum impregnation: The glass fiber mat is placed in a vacuum environment and impregnated with an impregnation precursor solution; the impregnation precursor solution is fully penetrated into the surface and internal pores of each fiber of the fiber mat by using negative pressure drive.

[0010] (3) Drying and foaming: The impregnated glass fiber felt is dried and then immersed in an aqueous solution of hydrazine hydrate for foaming reaction. After the reaction is completed, it is washed and dried; a three-dimensional porous gel skeleton is generated in situ within the fiber network. (4) High-temperature heat treatment: The foamed and dried composite fiber felt was heat-treated at 1000℃ under an argon protective atmosphere to obtain the graphene-ceramic aerogel composite glass fiber felt. In this step, graphene oxide is thermally reduced to a carbon network; simultaneously, the precursor sodium silicate undergoes hydrolysis-condensation during controlled pyrolysis, transforming in situ into an amorphous nano-silica ceramic phase. The two components synergistically evolve in a high-temperature environment, constructing a highly interconnected graphene-ceramic composite aerogel network through mechanisms such as interfacial diffusion, interpenetration, and local covalent bonding.

[0011] Most importantly, this composite aerogel phase not only self-assembles into a continuous porous structure within the fiber gaps, but also interacts with the glass fiber surface in multiple ways: on the one hand, the rGO sheets and SiO2 nanoparticles can achieve strong chemical coupling with the hydroxyl groups on the fiber surface through hydrogen bonds, van der Waals forces, and possible Si–O–C chemical bonds; on the other hand, the aerogel network is partially embedded in the micropores or rough structures of the fiber surface during sintering, forming an effective physical anchoring effect. Finally, the entire "rGO-ceramic" aerogel structure is permanently sintered and fixed within the three-dimensional glass fiber skeleton, ensuring both the spatial stability and service durability of the nano-insulating phase, while fully preserving the flexibility and processability of the macroscopic fiber felt, thus achieving an organic unity between microscopic ultra-insulating performance and macroscopic engineering applicability.

[0012] Furthermore, the glass fiber mat is one of high-silica glass fiber mat, quartz fiber mat, or basalt fiber mat. The high-silica glass fiber mat refers to a glass fiber mat with a SiO2 mass percentage ≥ 96%.

[0013] Furthermore, the vacuum degree of vacuum impregnation is not higher than -0.1 MPa, and the impregnation time is 0.5 hours to 2 hours.

[0014] Furthermore, the mass concentration of the hydrazine hydrate aqueous solution is 20%, the temperature of the foaming reaction is 60°C, and the reaction time is 1-5 minutes.

[0015] Furthermore, the drying method in step (3) is: drying in an oven at 80°C until constant weight.

[0016] Furthermore, the heating rate in step (4) is 2℃ / min-10℃ / min.

[0017] The present invention also provides an olefin-ceramic aerogel composite glass fiber mat prepared by the above method, the thermal conductivity of which is not higher than 20 mW / (m·K) at room temperature.

[0018] The present invention also provides the application of the above-mentioned olefin aerogel composite glass fiber mat in thermal insulation.

[0019] As a continuous macroscopic framework, glass fiber mat retains its inherent properties of flexibility, cutability, and bendability during the composite process. The silica ceramic phase formed at high temperatures enhances the connections between fibers rather than compromising overall flexibility. The resulting ceramic aerogel composite glass fiber mat can directly utilize all the processing and installation methods of traditional fiber mats.

[0020] The advantages of this invention lie in the fact that, through a process path of "vacuum impregnation-in-situ foaming-high-temperature conversion," uniform composite and firm bonding of the olefinic ceramic phase and glass fiber at the microscale is achieved. The prepared composite felt has a room-temperature thermal conductivity that can be reduced to 12 mW / (m·K)-20 mW / (m·K), which is significantly lower than that of the original glass fiber felt, resulting in superior thermal insulation performance. Furthermore, the chemical bonds and physical interlocking structure formed at high temperatures ensure the stability of the material structure. Attached Figure Description

[0021] Figure 1 This is a bending diagram of the olefin-ceramic aerogel composite glass fiber mat obtained in Example 1.

[0022] Figure 2 This is a scanning electron microscope image of the olefin-ceramic aerogel composite glass fiber mat obtained in Example 1. Detailed Implementation

[0023] The following examples are provided to further illustrate the present invention and are intended to explain the invention, not to limit its scope. Unless otherwise specified, all figures are expressed in parts by weight and weight percentages.

[0024] Unless otherwise specified, the raw materials used in this invention are all conventional commercially available products; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0025] The embodiments of the present invention will be further described below with reference to several examples.

[0026] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0027] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0028] Example 1 1) Preparation of precursor solution: Take 400g of graphene oxide aqueous dispersion with a solid content of 10mg / g (containing 4g of graphene oxide) and mix with 10g of sodium silicate aqueous solution with a modulus of 3.3 and a solid content of 20% (containing 2g of sodium silicate). Stir for 1 hour to obtain an impregnation solution with a mass ratio of graphene oxide to sodium silicate of 2:1.

[0029] 2) Vacuum Impregnation: Take a piece of high-silica glass fiber mat measuring 10cm × 10cm × 5mm (density approximately 120kg / m³) and place it in a vacuum impregnation tank. Evacuate to -0.1 MPa and maintain this vacuum for 30 minutes. While maintaining the vacuum, pour the impregnation solution prepared in step 1 into the tank, completely submerging the fiber mat. Continue impregnation for 1 hour.

[0030] 3) Drying and foaming: Remove the impregnated fiber felt and dry it in an 80°C oven for 12 hours until constant weight. Completely immerse the dried felt in a 20 wt% hydrazine hydrate aqueous solution at 60°C and allow it to foam for 3 minutes. After removal, wash with ethanol and dry again at 80°C.

[0031] 4) High-temperature heat treatment: The sample was placed in a tube furnace, and high-purity argon was introduced as a protective gas. The temperature was increased to 1000°C at a rate of 5°C / min, held for 2 hours, and then cooled to room temperature with the furnace. This yielded aerogel-coated glass fiber mat A1.

[0032] 5) The thermal conductivity was measured to be 12 mW / (m·K) by laser thermal conductivity method, and the compressive strength at 10% compressive strain was measured to be 1.45 MPa by universal testing machine.

[0033] Example 2 1) Preparation of precursor solution: Take 320g of graphene oxide aqueous dispersion with a solid content of 10mg / g (containing 3.2g of graphene oxide) and mix it with 16g of sodium silicate solution with a solid content of 20% (containing 3.2g of sodium silicate) to make the mass ratio of graphene oxide to sodium silicate 1:1.

[0034] 2) Vacuum Impregnation: Take a piece of high-silica glass fiber mat measuring 10cm × 10cm × 5mm (density approximately 120kg / m³) and place it in a vacuum impregnation tank. Evacuate to -0.1 MPa and maintain for 30 minutes. While maintaining the vacuum, pour the impregnation solution prepared in step 1 into the tank, completely immersing the fiber mat. Continue impregnation for 2 hours.

[0035] 3) Drying and foaming: Remove the impregnated fiber felt and dry it in an 80°C oven for 12 hours until constant weight. Completely immerse the dried felt in a 20 wt% hydrazine hydrate aqueous solution at 60°C and allow it to foam for 5 minutes. After removal, wash with ethanol and dry again at 80°C.

[0036] 4) High-temperature heat treatment: The sample was placed in a tube furnace, and high-purity argon was introduced as a protective gas. The temperature was increased to 1000°C at a rate of 2°C / min, held at that temperature for 2 hours, and then cooled to room temperature with the furnace. This yielded aerogel-coated glass fiber mat A2.

[0037] 5) The thermal conductivity was measured to be 18 mW / (m·K) by laser thermal conductivity method, and the compressive strength at 10% compressive strain was measured to be 1.45 MPa by universal testing machine.

[0038] Example 3 1) Preparation of precursor solution: Take 480g of graphene oxide aqueous dispersion with a solid content of 10mg / g (containing 4.8g of graphene oxide) and mix with 6g of sodium silicate aqueous solution with a solid content of 20% (containing 1.2g of sodium silicate) to make the mass ratio of graphene oxide to sodium silicate 4:1.

[0039] 2) Vacuum Impregnation: Take a piece of high-silica glass fiber mat measuring 10cm×10cm×5mm (density approximately 120kg / m³) and place it in a vacuum impregnation tank. Evacuate to -0.1 MPa and maintain this vacuum for 30 minutes. While maintaining the vacuum, pour the impregnation solution prepared in step 1 into the tank, completely immersing the fiber mat. Continue impregnation for 30 minutes.

[0040] 3) Drying and foaming: Remove the impregnated fiber felt and dry it in an 80°C oven for 12 hours until constant weight. Completely immerse the dried felt in a 20 wt% hydrazine hydrate aqueous solution at 60°C and allow it to foam for 5 minutes. After removal, wash with ethanol and dry again at 80°C.

[0041] 4) High-temperature heat treatment: The sample was placed in a tube furnace, and high-purity argon was introduced as a protective gas. The temperature was increased to 1000°C at a rate of 2°C / min, held at that temperature for 2 hours, and then cooled to room temperature with the furnace. This yielded aerogel-coated glass fiber mat A3.

[0042] 5) The thermal conductivity was measured to be 16 mW / (m·K) by laser thermal conductivity method, and the compressive strength at 10% compressive strain was measured to be 1.45 MPa by universal testing machine.

[0043] Example 4 1) Preparation of precursor solution: Take 480g of graphene oxide aqueous dispersion with a solid content of 10mg / g (containing 4.8g of graphene oxide) and mix with 6g of sodium silicate aqueous solution with a solid content of 20% (containing 1.2g of sodium silicate) to make the mass ratio of graphene oxide to sodium silicate 4:1.

[0044] 2) Vacuum Impregnation: Take a piece of high-silica glass fiber mat measuring 10cm×10cm×5mm (density approximately 120kg / m³) and place it in a vacuum impregnation tank. Evacuate to -0.1 MPa and maintain this vacuum for 30 minutes. While maintaining the vacuum, pour the impregnation solution prepared in step 1 into the tank, completely immersing the fiber mat. Continue impregnation for 60 minutes.

[0045] 3) Drying and foaming: Remove the impregnated fiber felt and dry it in an 80°C oven for 12 hours until constant weight. Completely immerse the dried felt in a 20 wt% hydrazine hydrate aqueous solution at 60°C and allow it to foam for 1 minute. After removal, wash with ethanol and dry again at 80°C.

[0046] 4) High-temperature heat treatment: The sample was placed in a tube furnace, and high-purity argon was introduced as a protective gas. The temperature was increased to 1000°C at a rate of 2°C / min, held for 2 hours, and then cooled to room temperature in the furnace. Aerogel-ceramic composite glass fiber mat A4 was obtained. The thermal conductivity was measured to be 19 mW / (m·K) by laser thermal conductivity method, and the compressive strength at 10% compressive strain was measured to be 1.45 MPa by universal testing machine.

[0047] Example 5 1) Preparation of precursor solution: Take 480g of graphene oxide aqueous dispersion with a solid content of 10mg / g (containing 4.8g of graphene oxide) and mix with 6g of sodium silicate aqueous solution with a solid content of 20% (containing 1.2g of sodium silicate) to make the mass ratio of graphene oxide to sodium silicate 4:1.

[0048] 2) Vacuum Impregnation: Take a piece of high-silica glass fiber mat measuring 10cm×10cm×5mm (density approximately 120kg / m³) and place it in a vacuum impregnation tank. Evacuate to -0.1 MPa and maintain this vacuum for 30 minutes. While maintaining the vacuum, pour the impregnation solution prepared in step 1 into the tank, completely immersing the fiber mat. Continue impregnation for 60 minutes.

[0049] 3) Drying and foaming: Remove the impregnated fiber felt and dry it in an 80°C oven for 12 hours until constant weight. Completely immerse the dried felt in a 20 wt% hydrazine hydrate aqueous solution at 60°C and allow it to foam for 4 minutes. After removal, wash with ethanol and dry again at 80°C.

[0050] 4) High-temperature heat treatment: The sample was placed in a tube furnace, and high-purity argon was introduced as a protective gas. The temperature was increased to 1000°C at a rate of 2°C / min, held for 2 hours, and then cooled to room temperature in the furnace. A olefin-ceramic aerogel composite glass fiber mat A5 was obtained. The thermal conductivity was measured to be 18 mW / (m·K) by laser thermal conductivity method, and the compressive strength at 10% compressive strain was measured to be 1.45 MPa by universal testing machine.

[0051] Comparative Example 1 The same batch of raw high-silica glass fiber mat as in Example 1 was taken without any treatment. The sample was designated D1. The thermal conductivity was measured to be 25 mW / (m·K) by laser thermal conductivity method, and the compressive strength at 10% compressive strain was measured to be 1.45 MPa by universal testing machine.

[0052] Comparative Example 2 Impregnation and heat treatment only, without foaming: After impregnation and drying according to steps 1 and 2 of Example 1, the glass fiber mat was directly subjected to the high-temperature heat treatment (1000°C, argon) in step 4. The resulting sample was designated D2, and its thermal conductivity was measured to be 23 mW / (m·K) using laser thermal conductivity method.

[0053] Comparative Example 3 Only the preparation, drying and foaming of the precursor solution and high-temperature heat treatment were performed: the precursor can be directly laid into a film, dried, foamed and then heat-treated. The resulting sample is recorded as D3. The thermal conductivity was measured to be 18 mW / (m·K) by laser thermal conductivity method, and the compressive strength at 10% compressive strain was measured to be 0.0032 MPa by universal testing machine.

[0054] Products A1-A5 obtained in Examples 1-5 all maintained a similar appearance, thickness, and excellent flexibility to the original felt D1, and could be used for cutting and curling. The thermal conductivity of products A1-A5 obtained in Examples 1-5 was significantly lower than that of samples D1 and D2.

[0055] The above embodiments describe in detail the structure, features, and effects of the present invention. The above description is only a preferred embodiment of the present invention. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall still fall within the scope of protection of the present invention if they do not exceed the scope covered by the specification.

Claims

1. A method for preparing an olefin-ceramic aerogel composite glass fiber mat, characterized in that, Includes the following steps: (1) Preparation of precursor solution: Mix the aqueous dispersion of graphene oxide with the aqueous solution of sodium silicate to obtain the impregnation precursor solution, wherein the mass ratio of graphene oxide to sodium silicate is not greater than 4:1; (2) Vacuum impregnation: The glass fiber mat is placed in a vacuum environment and impregnated with an impregnation precursor solution; (3) Drying and foaming: Dry the impregnated glass fiber felt, then immerse it in an aqueous solution of hydrazine hydrate for foaming reaction. After the reaction is completed, wash and dry it. (4) High temperature heat treatment: The foamed and dried composite fiber felt is heat treated at 1000℃ under an argon protective atmosphere to obtain the olefin aerogel composite glass fiber felt.

2. The method according to claim 1, characterized in that, The glass fiber mat is one of high silica glass fiber mat, quartz fiber mat, or basalt fiber mat.

3. The method according to claim 1, characterized in that, The vacuum degree of vacuum impregnation is not higher than -0.1 MPa, and the impregnation time is 0.5 hours to 2 hours.

4. The method according to claim 1, characterized in that, The hydrazine hydrate aqueous solution has a mass concentration of 20%, the foaming reaction temperature is 60°C, and the reaction time is 1-5 minutes.

5. The method according to claim 1, characterized in that, The drying method in step (3) is to dry in an 80°C oven until constant weight.

6. The method according to claim 1, characterized in that, The heating rate in step (4) is 2℃ / min-10℃ / min.

7. An olefin-ceramic aerogel composite glass fiber mat prepared by the method described in claim 1.

8. The epoxy-ceramic aerogel composite glass fiber mat according to claim 7, characterized in that, The thermal conductivity at room temperature is no higher than 20 mW / (m·K).

9. The application of the epoxy-ceramic aerogel composite glass fiber mat as described in claim 7 in thermal insulation.

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