Phenolic resin-based heat insulation and thermal control integrated composite material and preparation method thereof

Abstract

The invention provides a phenolic resin-based heat insulation and thermal control integrated composite material and a preparation method thereof, and the preparation method comprises the following steps: placing a fibrofelt in a modification solution for surface modification, cleaning, and drying to constant weight to obtain a surface modified fibrofelt; the preparation method comprises the following steps: dissolving phenolic resin in an organic solvent, heating and uniformly mixing, dropwise adding a phenyl-containing alkoxy silane monomer, heating and stirring for grafting modification reaction, and uniformly mixing with an organic solution in which a curing agent is dissolved to obtain a silicon-modified phenolic resin solution; placing the surface modified fiber felt in the silicon modified phenolic resin solution, completely dipping under a vacuum condition, and heating and curing at normal pressure to obtain a fiber felt silicon modified phenolic resin wet gel block; and soaking the wet gel block in an ethanol solution to remove the solvent, and drying to constant weight to obtain the phenolic resin-based heat prevention and insulation and thermal control integrated composite material. The toughness, ablation resistance and oxidation resistance of the whole composite material are improved.

Description

Technical Field

[0001] This invention relates to the field of thermal protection materials technology, specifically to a phenolic resin-based composite material integrating heat insulation and thermal control, and its preparation method. Background Technology

[0002] Fiber-reinforced phenolic resin thermal protection materials possess advantages such as lightweight, high strength, excellent flame retardancy, heat resistance, and ablation resistance, and are widely used in rockets, spacecraft, deep space exploration vehicles, and space shuttle vehicles. However, traditional phenolic resins experience significant weight loss under thermal oxidation conditions and exhibit high brittleness, limiting their further application in the field of thermal protection.

[0003] Furthermore, traditional fiber-reinforced phenolic resin thermal protection materials focus primarily on their thermal and mechanical properties, neglecting their optical properties. However, when operating in aerospace environments, these composite materials are subject to both ambient and internal thermal radiation, leading to temperature increases. Therefore, it is crucial to develop a fiber / phenolic resin composite material that integrates thermal insulation and thermal control. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a phenolic resin-based composite material integrating heat insulation and thermal control. This invention introduces organosilicon segments during the prepolymerization of phenolic resin and grafts silane segments onto the side chains of the phenolic resin, aiming to improve the heat resistance and toughness of the phenolic resin. Furthermore, optical parameters are controlled through porous structures, resulting in a low-density, low-thermal-conductivity, heat-resistant fiber / phenolic resin composite material with high infrared emissivity. Compared to the CC segments of phenolic resin, Si-Si and Si-O bonds have higher bond energies and longer bond lengths, thus the organosilicon segments exhibit higher heat resistance and toughness. In addition, Si elements oxidize to a SiO2 network at high temperatures, which can adhere to the composite material interface to protect the internal matrix. Moreover, since the -OH, CO, and CH bonds in phenolic resin and the Si-O bonds in quartz fibers all have strong characteristic absorption peaks in the infrared band, they possess high infrared emissivity, improving radiative heat dissipation.

[0005] The preparation method of the phenolic resin-based heat-insulating and thermal-control integrated composite material provided by the present invention includes the following steps: Step S1: The fiber felt is placed in the modification solution for surface modification, and after cleaning, it is dried to constant weight to obtain surface-modified fiber felt; Step S2: Dissolve phenolic resin in an organic solvent, heat and mix evenly, then add phenyl-containing alkoxysilane monomer dropwise, heat and stir to carry out grafting modification reaction, and then mix evenly with the organic solution of the curing agent to obtain silicone-modified phenolic resin solution. Step S3: Place the surface-modified fiber felt in the silicon-modified phenolic resin solution, and after complete impregnation under vacuum conditions, heat and cure under normal pressure to obtain fiber felt silicon-modified phenolic resin wet gel block. Step S4: After soaking the wet gel block in ethanol solution to remove the solvent, dry it to constant weight to obtain a phenolic resin-based heat insulation and thermal control integrated composite material.

[0006] Preferably, in step S1, the fiber felt is selected from quartz fiber needle-punched felt, carbon fiber needle-punched felt, glass fiber needle-punched felt, and carbon fiber-quartz fiber composite fiber felt, and the thickness of the fiber felt is 1-10 cm and the density is 0.16-0.25 g / cm³. 3 .

[0007] Preferably, in step S1, the modified solution is a mixed solution of γ-aminopropyltriethoxysilane and ethanol, wherein the mass ratio of γ-aminopropyltriethoxysilane to ethanol is 10:90.

[0008] Preferably, in step S2, the organic solvent is selected from methanol, ethanol, ethylene glycol or isopropanol, and the mass ratio of phenolic resin to organic solvent is 4:1.

[0009] Preferably, in step S2, the phenyl-containing alkoxysilane monomer is selected from phenyltrimethoxysilane, phenyltriethoxysilane, or diphenyldimethoxysilane; The ratio of phenolic resin to silane monomer is 40g phenolic resin to 0.023mol, 0.046mol, or 0.07mol silane monomer.

[0010] Preferably, in step S2, the heating and mixing temperature is 50-70°C, the silane monomer is added dropwise for 10 minutes, the temperature is raised to 90°C after the addition is complete, the stirring time is 60-90 minutes, and the stirring rate is 200 r / min. The curing agent is hexamethylenetetramine, and the mass ratio of the organic solvent to the phenolic resin solution in the organic solution dissolving the curing agent is 7:4 or 3:4.

[0011] Preferably, in step S3, the vacuum degree of vacuum impregnation is -0.08 to -0.06 MPa, the impregnation temperature is 90°C, and the impregnation time is 30 to 60 minutes. The heating and curing process involves heating at 110–130°C for 3 hours, followed by heating at 170–190°C for another 3 hours.

[0012] Preferably, in step S4, the solvent removal conditions are: heating at atmospheric pressure and 60-80°C for 36-48 hours, with the ethanol solution replaced every 12 hours, for a total heating time of 36-48 hours; The drying temperature is 30–50℃.

[0013] Preferably, the surface modification temperature is 70°C and the modification time is 2 hours; The cleaning process involves soaking in an ethanol solution for 1 hour followed by continuous rinsing for 5 minutes, and drying at a temperature of 30°C.

[0014] This invention provides a phenolic resin-based composite material integrating heat insulation and thermal control, prepared using the aforementioned method.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention introduces silane segments into the traditional phenolic resin chain segments, and reduces phase separation by chemically connecting the silane segments with the phenolic side chains. While maintaining the properties of the phenolic resin itself, it combines the heat resistance and toughness of the silane segments, thereby improving the overall toughness, ablation resistance, and oxidation resistance of the composite material.

[0016] 2. By introducing silane segments, this invention can effectively improve the thermal stability of the composite material, with a maximum mass retention rate of 68.6% at 800°C, compared to 47.8% in air at the same temperature.

[0017] 3. The infrared emissivity of the fiber felt / silicon-modified phenolic resin composite material prepared by this invention is greater than 0.94.

[0018] 4. This invention can control the density of the composite material by adjusting the composition of the reaction system, achieving a density as low as 0.3–0.5 g / cm³. 3 . Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. Other features, objects, and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a photograph of the porous composite material of carbon needle-punched fiber felt / phenyltriethoxysilane modified phenolic resin prepared in Example 1.

[0020] Figure 2 This is a photograph of the porous composite material of quartz needle-punched fiber felt / phenyltriethoxysilane modified phenolic resin prepared in Example 2.

[0021] Figure 3 The elemental distribution diagram is shown for the porous composite material prepared in Example 1.

[0022] Figure 4 The image shows the microstructure of the porous composite material prepared in Example 2.

[0023] Figure 5 Infrared emissivity curve of the porous composite material of quartz needle-punched fiber felt / phenyltriethoxysilane modified phenolic resin prepared in Example 2. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0025] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0027] The technical solutions of the present invention and how they solve the above-mentioned technical problems will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0028] Example 1: This embodiment provides a method for creating a carbon needle-punched fiber felt / phenyltriethoxysilane modified phenolic resin composite material, the specific steps of which are as follows: Step 1: [The following appears to be a separate, unrelated sentence:] The bulk density is 0.16 g / cm³. 3A carbon fiber felt of a certain size was placed in a KH550 ethanol mixed solution for surface modification. The mass ratio of KH550 to ethanol solvent was 10:90. After reacting at 70℃ for 2 hours, the carbon fiber felt was taken out and soaked in anhydrous ethanol for 1 hour. It was then taken out and continuously rinsed with anhydrous ethanol for 5 minutes. After that, it was dried in a forced-air drying oven at 30℃ to constant weight to obtain surface-modified fiber felt. Step 2: Dissolve the Shengquan PF9202-8F phenolic resin in ethylene glycol. The mass of phenolic resin and ethylene glycol are 40g and 10g respectively. Mix them evenly in a water bath at 60℃. Under the above heating conditions, 0.046 mol (11.057 g) of phenyltriethoxysilane was added dropwise to the phenolic resin solution. After the addition was completed in about 10 minutes, the temperature was gradually raised to 90°C, and stirring was continued for 60 minutes until the mixture was homogeneous and clear. The stirring rate was 200 r / min. 2 g of hexamethylenetetramine was dissolved in 70 g of ethylene glycol solution at room temperature and stirred until the hexamethylenetetramine was completely dissolved. Then, it was added dropwise to the above phenolic / phenyltriethoxysilane solution and mixed evenly to obtain a silicon-modified phenolic resin solution. Step 3: Place the dried modified carbon fiber felt in a silicon-modified phenolic resin solution, immerse it in a vacuum oven at 90°C for 30 minutes under vacuum conditions, then seal it in an oven and cure it at 120°C for 3 hours and 170°C for 3 hours under normal pressure to obtain a fiber felt / phenyltriethoxysilane modified phenolic resin wet gel block. Step 4: Immerse the fiber felt / silicon-modified phenolic resin wet gel block prepared in Step 3 in an ethanol solution, place it in a 70℃ forced-air drying oven to remove the solvent, replace the ethanol solvent every 12 hours, heat for a total of 48 hours, then take it out and dry it in a 50℃ forced-air drying oven to constant weight to obtain carbon fiber needle-punched felt / phenyltriethoxysilane-modified phenolic resin composite material.

[0029] See the physical image of the porous composite material prepared in Example 1. Figure 1 Its density is 0.36 g / cm³. 3 The mass residue rate at 800℃ in Ar atmosphere is 68.6%, and the mass residue rate in air atmosphere is 16.4%. The thermal conductivity is 0.1516W / mK, the solar absorptivity (250-2500nm) is 0.73, and the infrared emissivity (2.5-25μm) is 0.942.

[0030] Example 2: This embodiment provides a method for creating a quartz fiber needle-punched felt / phenyltriethoxysilane modified phenolic resin composite material, the specific steps of which are as follows: Step 1: [The following appears to be a separate, unrelated sentence:] The bulk density is 0.2 g / cm³. 3A quartz fiber felt of a certain size was placed in a KH550 ethanol mixed solution for surface modification. The mass ratio of KH550 to ethanol solvent was 10:90. After reacting at 70℃ for 2 hours, the quartz fiber felt was taken out and soaked in anhydrous ethanol for 1 hour. After soaking, it was taken out and rinsed continuously with anhydrous ethanol for 5 minutes. Then, it was dried in a forced-air drying oven at 30℃ to constant weight to obtain the surface-modified quartz fiber felt. Step 2: Dissolve Shengquan PF9202-8F phenolic resin in ethylene glycol, with 80g of phenolic resin and 20g of ethylene glycol. Heat the solution in a water bath at 60°C until homogeneous. Under the above heating and stirring conditions, gradually add 0.092mol (22.114g) of phenyltriethoxysilane to the phenolic resin solution, completing the addition in about 10 minutes. Then gradually raise the temperature to 90°C and continue stirring for 60 minutes until homogeneous and clear. The stirring rate is 200r / min. Dissolve 4g of hexamethylenetetramine in 140g of ethylene glycol solution at room temperature and continue stirring until the hexamethylenetetramine is completely dissolved. Then add the solution dropwise to the above phenolic / phenyltriethoxysilane solution and mix until homogeneous to obtain a silicon-modified phenolic resin solution. Step 3: Place the dried modified quartz fiber felt in a silicon-modified phenolic resin solution, circulate and impregnate it at 90°C for 60 minutes under vacuum conditions in a vacuum drying oven, then seal it in an oven and heat it at normal pressure at 110°C for 3 hours and 180°C for 3 hours to obtain a quartz fiber felt / phenyltriethoxysilane modified phenolic resin wet gel block. Step 4: Immerse the quartz fiber felt / silicon-modified phenolic resin wet gel block prepared in Step 3 in an ethanol solution, place it in a 70℃ forced-air drying oven to remove the solvent, replace the ethanol solvent every 12 hours, and heat for a total of 48 hours. Then take it out and dry it in a 50℃ forced-air drying oven to constant weight to obtain the quartz fiber needle-punched felt / phenyltriethoxysilane-modified phenolic resin composite material.

[0031] See the physical image of the porous composite material prepared in Example 2. Figure 2 Its density is 0.42 g / cm³. 3 The mass residue at 800℃ in an Ar atmosphere was 65.5%, and in an air atmosphere it was 47.9%. The thermal conductivity was 0.07 W / mK. The solar absorptivity (250-2500 nm) was 0.324, and the infrared emissivity (2.5-25 μm) was 0.961. The infrared emission spectrum is shown below. Figure 5 Compared with Example 1, the difference is that quartz fiber felt is used as the reinforcing phase. The intrinsic properties of quartz fiber reduce solar absorptivity and increase infrared emissivity, thereby providing better thermal control performance.

[0032] Example 3: This embodiment provides a method for creating a carbon needle-punched fiber felt / diphenyldimethoxysilane modified phenolic resin composite material, the specific steps of which are as follows: Step 1: [The following appears to be a separate, unrelated sentence:] The bulk density is 0.16 g / cm³. 3 A carbon fiber felt of a certain size was placed in a KH550 ethanol mixed solution for surface modification. The mass ratio of KH550 to ethanol solvent was 10:90. After reacting at 70℃ for 2 hours, the carbon fiber felt was taken out and soaked in anhydrous ethanol for 1 hour. It was then taken out and continuously rinsed with anhydrous ethanol for 5 minutes. After that, it was dried in a forced-air drying oven at 30℃ to constant weight to obtain surface-modified fiber felt. Step 2: Dissolve Shengquan PF9202-8F phenolic resin in ethylene glycol, with 40g of phenolic resin and 10g of ethylene glycol. Mix thoroughly in a water bath at 60°C. Under the above heating conditions, add 0.07mol (17.1052g) of diphenyldimethoxysilane dropwise to the phenolic resin solution. After the addition is completed in about 10 minutes, gradually raise the temperature to 90°C and continue stirring for 60 minutes until the mixture is clear and transparent. The stirring rate is 200r / min. Dissolve 2g of hexamethylenetetramine in 30g of ethylene glycol solution at room temperature. Continue stirring until the hexamethylenetetramine is completely dissolved. Then add it dropwise to the above phenolic / diphenyldimethoxysilane solution and mix thoroughly to obtain a silicon-modified phenolic resin solution. Step 3: Place the dried modified carbon fiber felt in a silicon-modified phenolic resin solution, immerse it in a vacuum oven at 90°C for 40 minutes under vacuum conditions, then seal it in an oven and cure it at 110°C for 3 hours and 180°C for 3 hours under normal pressure to obtain fiber felt / diphenyldimethoxysilane modified phenolic resin wet gel block. Step 4: Immerse the carbon fiber felt / silicon-modified phenolic resin wet gel block prepared in Step 3 in an ethanol solution, place it in a 70℃ forced-air drying oven to remove the solvent, replace the ethanol solvent every 12 hours, heat for a total of 48 hours, then take it out and dry it in a 50℃ forced-air drying oven to constant weight to obtain carbon fiber needle-punched felt / diphenyldimethoxysilane-modified phenolic resin composite material.

[0033] Example 4: The difference between this embodiment and Embodiment 1 is that the solvent in step two is ethanol, and the modified silane used is phenyltrimethoxysilane with a content of 0.07 mol, or 13.8803 g.

[0034] Example 5: The difference between this embodiment and Embodiment 2 is that the density of the quartz fiber felt is 0.16 g / cm³. 3 Furthermore, the mass ratio of phenolic resin to solvent ethylene glycol is 1:1, and the content of phenyltriethoxysilane used is 0.046 mol, or 11.057 g.

[0035] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0036] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing a phenolic resin-based composite material integrating heat insulation and thermal control, characterized in that, Includes the following steps: Step S1: The fiber felt is placed in the modification solution for surface modification, and after cleaning, it is dried to constant weight to obtain surface-modified fiber felt; Step S2: Dissolve phenolic resin in an organic solvent, heat and mix evenly, then add phenyl-containing alkoxysilane monomer dropwise, heat and stir to carry out grafting modification reaction, and then mix evenly with the organic solution of the curing agent to obtain silicone-modified phenolic resin solution. Step S3: Place the surface-modified fiber felt in the silicon-modified phenolic resin solution, and after complete impregnation under vacuum conditions, heat and cure under normal pressure to obtain fiber felt silicon-modified phenolic resin wet gel block. Step S4: After soaking the wet gel block in ethanol solution to remove the solvent, dry it to constant weight to obtain a phenolic resin-based heat insulation and thermal control integrated composite material.

2. The preparation method according to claim 1, characterized in that, In step S1, the fiber felt is selected from quartz fiber needle-punched felt, carbon fiber needle-punched felt, glass fiber needle-punched felt, and carbon fiber-quartz fiber composite fiber felt. The thickness of the fiber felt is 1-10 cm, and the density is 0.16-0.25 g / cm³. 3 .

3. The preparation method according to claim 1 or 2, characterized in that, In step S1, the modified solution is a mixed solution of γ-aminopropyltriethoxysilane and ethanol, wherein the mass ratio of γ-aminopropyltriethoxysilane to ethanol is 10:

90.

4. The preparation method according to claim 1, characterized in that, In step S2, the organic solvent is selected from methanol, ethanol, ethylene glycol or isopropanol, and the mass ratio of phenolic resin to organic solvent is 4:

1.

5. The preparation method according to claim 1, characterized in that, In step S2, the phenyl-containing alkoxysilane monomer is selected from phenyltrimethoxysilane, phenyltriethoxysilane, or diphenyldimethoxysilane. The ratio of phenolic resin to silane monomer is 40g phenolic resin to 0.023mol, 0.046mol, or 0.07mol silane monomer.

6. The preparation method according to claim 1, characterized in that, In step S2, the heating and mixing temperature is 50-70°C, the silane monomer is added dropwise for 10 minutes, and after the addition is complete, the temperature is raised to 90°C. The stirring time is 60-90 minutes, and the stirring rate is 200 r / min. The curing agent is hexamethylenetetramine, and the mass ratio of the organic solvent to the phenolic resin solution in the organic solution dissolving the curing agent is 7:4 or 3:

4.

7. The preparation method according to claim 1, characterized in that, In step S3, the vacuum degree of vacuum impregnation is -0.08 to -0.06 MPa, the impregnation temperature is 90°C, and the impregnation time is 30 to 60 minutes. The heating and curing process involves heating at 110–130°C for 3 hours, followed by heating at 170–190°C for another 3 hours.

8. The preparation method according to claim 1, characterized in that, In step S4, the solvent removal conditions are: heating at atmospheric pressure and 60-80°C for 36-48 hours, with the ethanol solution replaced every 12 hours, for a total heating time of 36-48 hours. The drying temperature is 30–50℃.

9. The preparation method according to claim 1, characterized in that, The surface modification temperature is 70℃, and the modification time is 2h; The cleaning process involves soaking in an ethanol solution for 1 hour followed by continuous rinsing for 5 minutes, and drying at a temperature of 30°C.

10. A phenolic resin-based composite material integrating heat insulation and thermal control, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 9.

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