Ablation type directional heat dissipation composite material and preparation method thereof

Abstract

The application provides an ablative directional heat dissipation composite material and a preparation method thereof, and belongs to the technical field of heat protection materials. The preparation method of the directional heat dissipation composite material comprises the following steps: S1. mixing phenolic resin, a catalyst and a solvent to obtain a precursor solution; S2. placing a directional heat dissipation skeleton material in the precursor solution to perform vacuum impregnation, sol-gel reaction and drying to obtain the ablative directional heat dissipation composite material. The directional heat dissipation skeleton material comprises at least one layer of heat insulation fiber layer and heat conduction fiber layer which are alternately arranged. The ablative directional heat dissipation composite material provided by the application has heat insulation in the vertical in-plane direction and high heat conduction in the in-plane direction. The high temperature generated locally can be rapidly dissipated to other low temperature areas, heat homogenization is achieved, the phenomenon of excessively high local temperature can be effectively prevented, and the heat insulation efficiency of the heat protection material is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of thermal protection materials technology, and specifically relates to an ablation-type directional thermally conductive composite material and its preparation method. Background Technology

[0002] Currently, existing ablation-type thermal insulation materials in the field of thermal protection exhibit low thermal conductivity in all internal directions. This prevents the rapid dissipation of locally generated high temperatures to other low-temperature zones, hindering heat homogenization and resulting in low insulation efficiency and a tendency to generate sharp singularities. Therefore, there is an urgent need for a thermal protection material that can rapidly dissipate locally generated high temperatures to other low-temperature zones while possessing high insulation efficiency. This would ensure thermal safety while increasing the operating temperature of the thermal protection material, enabling it to meet the demands of more demanding application scenarios. Summary of the Invention

[0003] To address one or more technical problems existing in the prior art, the present invention provides an ablation-type directional thermal conductive composite material and its preparation method. The ablation-type directional thermal conductive composite material provided by the present invention has thermal insulation properties along the vertical in-plane direction and high thermal conductivity along the in-plane direction. It can quickly conduct locally generated high temperatures to other low-temperature areas, achieve heat homogenization, effectively prevent local overheating, and significantly improve the thermal insulation efficiency of thermal protection materials.

[0004] The present invention provides a method for preparing an ablation-type directional thermally conductive composite material in a first aspect, the method comprising the following steps:

[0005] S1. Mix phenolic resin, catalyst and solvent to obtain precursor solution;

[0006] S2. The directional thermally conductive framework material is placed in a precursor solution for vacuum impregnation, sol-gel reaction, and drying to obtain the ablation-type directional thermally conductive composite material.

[0007] The directional heat-conducting skeleton material consists of at least one alternating layer of heat-insulating fiber and one layer of heat-conducting fiber.

[0008] Preferably, the phenolic resin and catalyst account for 15-25% of the mass of the precursor solution;

[0009] Preferably, the phenolic resin is a thermosetting phenolic resin; and the catalyst is hexamethylenetetramine.

[0010] Preferably, the mass ratio of the phenolic resin to the catalyst is (5-8):1.

[0011] Preferably, the directional heat-conducting skeleton material is obtained by integral curing and heat treatment of alternating layers of heat-insulating fiber and heat-conducting fiber;

[0012] Preferably, the directional heat-conducting skeleton material has one more heat-insulating fiber layer than the heat-conducting fiber layer.

[0013] Preferably, the heat-insulating fiber layer comprises viscose-based carbon fiber and phenolic resin; more preferably, the mass ratio of the viscose-based carbon fiber and phenolic resin is 1:1.

[0014] Preferably, the thermally conductive fiber layer comprises highly thermally conductive carbon fiber and phenolic resin; more preferably, the mass ratio of the highly thermally conductive carbon fiber to the phenolic resin is 1:1.

[0015] Preferably, the number of thermally conductive fiber layers in the directional thermally conductive skeleton material is 1 to 4, and more preferably 1 to 2.

[0016] Preferably, the thickness of the single-layer thermally conductive fiber layer is 1 to 4 mm.

[0017] Preferably, the vacuum impregnation time is 24 to 36 hours.

[0018] Preferably, the sol-gel reaction is carried out at a temperature of 75–85°C for 48–52 hours.

[0019] In a second aspect, the present invention provides an ablation-type directional thermally conductive composite material, which is prepared using the preparation method described in the first aspect.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects.

[0021] This invention involves impregnating phenolic aerogel with a directional thermally conductive framework material comprising alternating layers of insulating and conductive fibers by impregnating a precursor solution, resulting in an ablation-type directional thermally conductive composite material with both insulating and conductive layers. This ablation-type directional thermally conductive composite material exhibits thermal insulation along the vertical in-plane direction and high thermal conductivity along the in-plane direction, enabling rapid conduction of locally generated high temperatures to other low-temperature regions, achieving heat homogenization, effectively preventing excessively high local temperatures, thereby increasing the material's operating temperature and significantly improving the thermal insulation efficiency of thermal protection materials. Attached Figure Description

[0022] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a physical image of the ablation-type directional thermally conductive composite material of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] The present invention provides a method for preparing an ablation-type directional thermally conductive composite material in a first aspect, the method comprising the following steps:

[0026] S1. Mix phenolic resin, catalyst and solvent to obtain precursor solution;

[0027] S2. The directional thermally conductive framework material is placed in a precursor solution for vacuum impregnation, sol-gel reaction, and drying to obtain the ablation-type directional thermally conductive composite material.

[0028] The directional heat-conducting skeleton material consists of at least one alternating layer of heat-insulating fiber and one layer of heat-conducting fiber.

[0029] This invention involves impregnating phenolic aerogel with a directional thermally conductive framework material comprising alternating layers of insulating and conductive fibers by impregnating a precursor solution, resulting in an ablation-type directional thermally conductive composite material with both insulating and conductive layers. This directional thermally conductive composite material exhibits thermal insulation along the vertical in-plane direction and high thermal conductivity along the in-plane direction, enabling rapid conduction of locally generated high temperatures to other low-temperature areas, achieving heat homogenization, effectively preventing excessively high local temperatures, thereby increasing the material's operating temperature and significantly improving the thermal insulation efficiency of thermal protection materials.

[0030] According to some preferred embodiments, the phenolic resin and catalyst account for 15-25% of the mass of the precursor solution (e.g., 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, or 25%); preferably, the phenolic resin is a thermosetting phenolic resin; the thermosetting phenolic resin used in this invention is THC-800 from Shaanxi Taihang Fire Retardant Polymer Co., Ltd., but is not limited to this model, other thermosetting phenolic resins may also be used; the catalyst is hexamethylenetetramine.

[0031] According to some preferred embodiments, the mass ratio of the phenolic resin to the catalyst is (5-8):1 (for example, it can be 5:1, 6:1, 7:1 or 8:1).

[0032] The inventors discovered that when the total content of reactants (phenolic resin and catalyst) is less than 15%, for example, 10%, the particle size and pore size of the phenolic aerogel decrease significantly with increasing reactant mass fraction. When the reactant mass fraction is too high (greater than 25%), due to the limited solubility of ethanol, the phenolic resin cannot react completely with hexamethylenetetramine, thus forming a solid precipitate with poor cross-linking of the three-dimensional network structure, resulting in a smooth, glossy sample surface and high density. Controlling the reactant mass fraction to 15-25% allows for the formation of a complete three-dimensional network structure, which can be dried at normal pressure to form an aerogel with a certain strength.

[0033] The inventors discovered that as the catalyst content (mass ratio of catalyst to phenolic resin) decreases, both the particle size and pore size of the aerogel gradually decrease. This is because hexamethylenetetramine (HMTA) acts as both a catalyst and a cross-linking agent in the reaction. HMTA's catalytic effect causes the phenolic resin to continuously aggregate, forming oligomer clusters, while HMTA's cross-linking effect causes the oligomers to interlock and form chain-like structures. When the HMTA content is relatively high, the clusters and oligomer chains continue to grow while overlapping and agglomerating, reaching a critical point of compatibility with the solvent, and the diameter continues to increase until spinomeric phase separation occurs. When the HMTA content is relatively low, the catalytic effect promoting polymer particle growth is relatively weak, but cross-linking still occurs, resulting in tightly bound oligomers and polymers. The aerogel pore size and particle size decrease, but the chain length increases. As the catalyst content decreases, the linear shrinkage during the drying process of the phenolic aerogel initially increases and then decreases; when the linear shrinkage rate is too high, the aerogel is prone to cracking. Therefore, by controlling the catalyst content (mass ratio of catalyst to phenolic resin) within the above-mentioned range, the present invention can ensure the production of phenolic aerogels with superior structure and performance.

[0034] According to some preferred embodiments, the directional thermal conductive skeleton material is obtained by integral curing and heat treatment of alternating layers of thermally insulating fiber and thermally conductive fiber; preferably, the curing temperature is 150-160°C and the time is 1-1.5h; the heat treatment is carried out in an argon atmosphere, with the temperature increased to 1000°C at a heating rate of 2°C / min and held for 2h; the argon flow rate is 100mL / min.

[0035] Preferably, the directional heat-conducting skeleton material has one more heat-insulating fiber layer than the heat-conducting fiber layer.

[0036] The preparation method of the directional thermally conductive framework material of the present invention is as follows:

[0037] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers. The mass of the amide is 5-7% of the mass of the high thermal conductivity carbon fiber; (2) Dispersion I and dispersion II are divided into several portions, and each portion of dispersion I and each portion of dispersion II are poured into the mold alternately until all of dispersion I and dispersion II are poured out. After each portion of dispersion I or dispersion II is poured out, it is filtered once. Finally, it is cured at 150-160℃ for 1-1.5h. Under argon atmosphere, the temperature is raised to 1000℃ at a heating rate of 2℃ / min and kept at the temperature for 2h. The argon flow rate is 100mL / min to obtain the directional thermal conductivity skeleton material.

[0038] According to some preferred embodiments, the heat-insulating fiber layer comprises viscose-based carbon fiber and phenolic resin; preferably, the mass ratio of the viscose-based carbon fiber and phenolic resin is 1:1.

[0039] According to some preferred embodiments, the thermally conductive fiber layer comprises highly thermally conductive carbon fibers and phenolic resin; preferably, the mass ratio of the highly thermally conductive carbon fibers to the phenolic resin is 1:1.

[0040] According to some preferred embodiments, the number of thermally conductive fiber layers in the directional thermally conductive skeleton material is 1 to 4 (for example, it can be 1, 2, 3 or), preferably 1 to 2.

[0041] According to some preferred embodiments, the thickness of the single-layer thermally conductive fiber layer is 1 to 4 mm (for example, it can be 1 mm, 2 mm, 3 mm or 4 mm).

[0042] The thermal conductivity in the Z-direction of the ablation-type directional thermally conductive composite material containing phenolic aerogel in this invention is significantly lower than that of the directional thermally conductive framework material. The phenolic aerogel composite material is beneficial for reducing the Z-direction thermal conductivity of the directional thermally conductive composite material. Compared with the directional thermally conductive framework material, the Z-direction thermal conductivity of the ablation-type directional thermally conductive composite material containing phenolic aerogel in this invention is significantly reduced. When the number of thermally conductive fiber layers is 1-2, the Z-direction thermal conductivity of the composite material is lower than that of the composite material without thermally conductive fiber layers, resulting in better thermal insulation performance.

[0043] The thermal conductivity of the directional thermally conductive composite material with thermally conductive fiber layer in the Z direction is significantly lower than that of the directional thermally conductive skeleton material. When the thickness of the thermally conductive fiber layer is 1 mm, the thermal conductivity of the composite material in the Z direction is less than that of the directional thermally conductive skeleton material without thermally conductive fiber layer. That is, the thermally conductive fiber layer with a thickness of 1 mm has a better heat insulation effect.

[0044] According to some preferred embodiments, the vacuum impregnation time is 24–36 hours (e.g., 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours, or 36 hours); and / or

[0045] The sol-gel reaction is carried out at a temperature of 75–85°C (e.g., 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, or 85°C) for a time of 48–52 hours (e.g., 48 hours, 49 hours, 50 hours, 51 hours, or 52 hours).

[0046] In a second aspect, the present invention provides an ablation-type directional thermally conductive composite material, which is prepared using the preparation method described in the first aspect.

[0047] To more clearly illustrate the technical solution and advantages of the present invention, the present invention will be further described below in conjunction with embodiments.

[0048] The materials and reagents used in this invention can be purchased directly from the market or synthesized in-house, and there are no restrictions on the specific models.

[0049] Example 1

[0050] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0051] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80°C for 48 hours for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material. The directional thermally conductive skeleton material includes three layers of thermally insulating fiber and two layers of thermally conductive fiber, with a thickness of 1 mm for each thermally conductive fiber layer and a total thickness of 15 mm for the directional thermally conductive skeleton material.

[0052] The thermal conductivity of the directional thermally conductive composite material prepared in Example 1 in the Z direction at room temperature is shown in Table 1.

[0053] Example 2

[0054] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0055] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80°C for 48 hours for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material. The directional thermally conductive skeleton material includes three alternately distributed thermal insulation fiber layers and two thermally conductive fiber layers. The thickness of a single thermally conductive fiber layer is 2 mm, and the total thickness of the directional thermally conductive skeleton material is 15 mm.

[0056] The thermal conductivity of the directional thermally conductive composite material prepared in Example 2 in the Z direction at room temperature is shown in Table 1.

[0057] Example 3

[0058] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0059] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80°C for 48 hours for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material. The directional thermally conductive skeleton material includes three layers of thermally insulating fiber and two layers of thermally conductive fiber, with a thickness of 3 mm for each thermally conductive fiber layer and a total thickness of 15 mm for the directional thermally conductive skeleton material.

[0060] The thermal conductivity of the directional thermally conductive composite material prepared in Example 3 in the Z direction at room temperature is shown in Table 1.

[0061] Example 4

[0062] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0063] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80°C for 48 hours for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material. The directional thermally conductive skeleton material includes 5 layers of heat-insulating fiber and 4 layers of heat-conducting fiber, with a thickness of 4 mm for each heat-conducting fiber layer and a total thickness of 15 mm for the directional thermally conductive skeleton material.

[0064] The thermal conductivity of the directional thermally conductive composite material prepared in Example 4 in the Z direction at room temperature is shown in Table 1.

[0065] Example 5

[0066] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0067] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80°C for 48 hours for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material, wherein the directional thermally conductive skeleton material is a thermal insulation fiber layer with a thickness of 15 mm.

[0068] The thermal conductivity of the directional thermally conductive composite material prepared in Example 5 in the Z direction at room temperature is shown in Table 1.

[0069] Example 6

[0070] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added in sequence. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained. The mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers. Dispersion I is poured into a mold for pressure filtration and finally cured at 150°C for 1 h. Under an argon atmosphere, the temperature is raised to 1000°C at a heating rate of 2°C / min and held for 2 h. The argon flow rate is 100 mL / min, and a directional thermally conductive skeleton material with a total thickness of 15 mm is obtained.

[0071] The thermal conductivity of the composite material obtained in Example 6 in the Z direction at room temperature is shown in Table 1.

[0072] Example 7

[0073] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of high thermal conductivity carbon fibers. (2) Divide dispersion I into 3 equal parts and dispersion II into 2 equal parts. Pour the three parts of dispersion I and the two parts of dispersion II into the mold alternately until all of dispersion I and dispersion II are poured out. After each part of dispersion I or dispersion II is poured out, perform a pressure filter. Finally, solidify at 150°C for 1 hour. Under an argon atmosphere, raise the temperature to 1000°C at a heating rate of 2°C / min and keep it at that temperature for 2 hours. The argon flow rate is 100 mL / min. This yields a directional thermal conductive skeleton material with 3 layers of heat insulation fiber and 2 layers of heat conduction fiber, with a single layer of heat conduction fiber having a thickness of 1 mm and a total thickness of 15 mm.

[0074] The thermal conductivity of the composite material prepared in Example 7 in the Z direction at room temperature is shown in Table 1.

[0075] Example 8

[0076] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of high thermal conductivity carbon fibers. (2) Divide dispersion I into 3 equal parts and dispersion II into 2 equal parts. Pour the three parts of dispersion I and the two parts of dispersion II into the mold alternately until all the dispersion I and dispersion II are poured out. After each part of dispersion I or dispersion II is poured out, perform a pressure filter. Finally, solidify at 150°C for 1 hour. Under an argon atmosphere, raise the temperature to 1000°C at a heating rate of 2°C / min and keep it at that temperature for 2 hours. The argon flow rate is 100 mL / min. This yields a directional thermal conductive skeleton material with 3 layers of heat insulation fiber and 2 layers of heat conduction fiber, with a single layer of heat conduction fiber having a thickness of 2 mm and a total thickness of 15 mm.

[0077] The thermal conductivity of the composite material obtained in Example 8 in the Z direction at room temperature is shown in Table 1.

[0078] Example 9

[0079] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of high thermal conductivity carbon fibers. (2) Divide dispersion I into 3 equal parts and dispersion II into 2 equal parts. Pour the three parts of dispersion I and the two parts of dispersion II into the mold alternately until all of dispersion I and dispersion II are poured out. After each part of dispersion I or dispersion II is poured out, perform a pressure filter. Finally, solidify at 150°C for 1 hour. Under an argon atmosphere, raise the temperature to 1000°C at a heating rate of 2°C / min and keep it at that temperature for 2 hours. The argon flow rate is 100 mL / min. This yields a directional thermal conductive skeleton material with 3 layers of heat insulation fiber and 2 layers of heat conduction fiber, with a single layer of heat conduction fiber having a thickness of 3 mm and a total thickness of 15 mm.

[0080] The thermal conductivity of the composite material obtained in Example 9 in the Z direction at room temperature is shown in Table 1.

[0081] Example 10

[0082] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of high thermal conductivity carbon fibers. (2) Divide dispersion I into 3 equal parts and dispersion II into 2 equal parts. Pour the three parts of dispersion I and the two parts of dispersion II into the mold alternately until all of dispersion I and dispersion II are poured out. After each part of dispersion I or dispersion II is poured out, perform a pressure filter. Finally, solidify at 150°C for 1 hour. Under an argon atmosphere, raise the temperature to 1000°C at a heating rate of 2°C / min and keep it at that temperature for 2 hours. The argon flow rate is 100 mL / min. This yields a directional thermal conductive skeleton material with 3 layers of heat-insulating fiber and 2 layers of heat-conducting fiber, with a single layer of heat-conducting fiber having a thickness of 4 mm and a total thickness of 15 mm.

[0083] The thermal conductivity of the composite material obtained by the 10-step process in the Z direction at room temperature is shown in Table 1.

[0084] Table 1

[0085]

[0086] It should be noted that the directional heat conduction skeleton materials in Examples 1-4 were prepared using the methods of Examples 7-10, and the directional heat conduction skeleton material in Example 5 was prepared using the method of Example 6; the Z direction of this invention is the in-plane direction.

[0087] Example 11

[0088] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0089] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80°C for 48 hours for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material. The directional thermally conductive skeleton material includes two alternately distributed thermal insulation fiber layers and one thermally conductive fiber layer. The thickness of a single thermally conductive fiber layer is 1 mm, and the total thickness of the directional thermally conductive skeleton material is 15 mm.

[0090] The thermal conductivity of the directional thermally conductive composite material prepared in Example 11 in the Z direction at room temperature is shown in Table 2.

[0091] Example 12

[0092] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0093] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80℃ for 48h for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material. The directional thermally conductive skeleton material includes three alternately distributed thermal insulation fiber layers and two thermally conductive fiber layers, with a single thermally conductive fiber layer having a thickness of 1mm; the total thickness of the directional thermally conductive skeleton material is 15mm.

[0094] The thermal conductivity of the directional thermally conductive composite material prepared in Example 12 in the Z direction at room temperature is shown in Table 2.

[0095] Example 13

[0096] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0097] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80°C for 48 hours for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material. The directional thermally conductive skeleton material includes 4 layers of thermally insulating fiber and 3 layers of thermally conductive fiber, with a thickness of 1 mm for each thermally conductive fiber layer. The total thickness of the directional thermally conductive skeleton material is 15 mm.

[0098] The thermal conductivity of the directional thermally conductive composite material prepared in Example 13 in the Z direction at room temperature is shown in Table 2.

[0099] Example 14

[0100] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0101] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80℃ for 48h for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material. The directional thermally conductive skeleton material consists of only 5 layers of thermal insulation fiber and 4 layers of thermally conductive fiber, with a single thermally conductive fiber layer having a thickness of 1mm. The total thickness of the directional thermally conductive skeleton material is 15mm.

[0102] The thermal conductivity of the directional thermally conductive composite material prepared in Example 14 in the Z direction at room temperature is shown in Table 2.

[0103] Example 15

[0104] S1. Place the thermosetting phenolic resin in a beaker containing anhydrous ethanol, seal it with plastic wrap, place it on a magnetic stirrer, and stir at 80°C until the phenolic resin is completely dissolved. Then add hexamethylenetetramine and wait for it to completely dissolve to obtain a precursor solution. The thermosetting phenolic resin and hexamethylenetetramine account for 15% of the mass of the precursor solution, and the mass ratio of thermosetting phenolic resin to hexamethylenetetramine is 7:1.

[0105] S2. The directional thermally conductive skeleton material is placed in a precursor solution for vacuum impregnation, kept at 80°C for 48 hours for sol-gel reaction, and dried under normal pressure to obtain the directional thermally conductive composite material, wherein the directional thermally conductive skeleton material is a thermal insulation fiber layer with a thickness of 15 mm.

[0106] The thermal conductivity of the composite material obtained in Example 15 in the Z direction at room temperature is shown in Table 2.

[0107] Example 16

[0108] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added in sequence. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained. The mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers. (2) Dispersion I is poured into a mold and cured at 150℃ for 1 h. Under an argon atmosphere, the temperature is raised to 1000℃ at a heating rate of 2℃ / min and held for 2 h. The argon flow rate is 100 mL / min, and a directional thermally conductive skeleton material with a total thickness of 15 mm is obtained.

[0109] The thermal conductivity of the directional thermally conductive framework material prepared in Example 16 in the Z direction at room temperature is shown in Table 2.

[0110] Example 17

[0111] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of high thermal conductivity carbon fibers. (1) 5-7% of the mass of the material; (2) Divide the dispersion I into two equal parts, and pour the two dispersions I and II into the mold alternately until all the dispersions I and II are poured out. After each part of dispersion I or dispersion II is poured out, perform a pressure filter. Finally, solidify at 150°C for 1 hour. Under an argon atmosphere, raise the temperature to 1000°C at a heating rate of 2°C / min and keep it at that temperature for 2 hours. The argon flow rate is 100 mL / min. Two layers of heat-insulating fiber and one layer of heat-conducting fiber are alternately distributed. The thickness of a single layer of heat-conducting fiber is 1 mm, and the total thickness is 15 mm.

[0112] The thermal conductivity of the directional thermally conductive framework material prepared in Example 17 in the Z direction at room temperature is shown in Table 2.

[0113] Example 18

[0114] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of high thermal conductivity carbon fibers. (2) Divide dispersion I into 3 equal parts and dispersion II into 2 equal parts. Pour the three parts of dispersion I and the two parts of dispersion II into the mold alternately until all of dispersion I and dispersion II are poured out. After each part of dispersion I or dispersion II is poured out, perform a pressure filter. Finally, solidify at 150°C for 1 hour. Under an argon atmosphere, raise the temperature to 1000°C at a heating rate of 2°C / min and keep it at that temperature for 2 hours. The argon flow rate is 100 mL / min. This yields a directional thermal conductive skeleton material with 3 layers of heat insulation fiber and 2 layers of heat conduction fiber, with a single layer of heat conduction fiber having a thickness of 1 mm and a total thickness of 15 mm.

[0115] The thermal conductivity of the composite material obtained in Example 18 in the Z direction at room temperature is shown in Table 2.

[0116] Example 19

[0117] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of high thermal conductivity carbon fibers. (2) Divide dispersion I into 4 equal parts and dispersion II into 3 equal parts. Pour the three parts of dispersion I and the two parts of dispersion II into the mold alternately until all of dispersion I and dispersion II are poured out. After each part of dispersion I or dispersion II is poured out, perform a pressure filtration. Finally, solidify at 150°C for 1 hour. Under an argon atmosphere, raise the temperature to 1000°C at a heating rate of 2°C / min and keep it at that temperature for 2 hours. The argon flow rate is 100 mL / min. This yields a directional thermal conductive skeleton material with 4 layers of heat-insulating fiber and 3 layers of heat-conducting fiber, with a single layer of heat-conducting fiber having a thickness of 1 mm and a total thickness of 15 mm.

[0118] The thermal conductivity of the composite material prepared in Example 19 in the Z direction at room temperature is shown in Table 2.

[0119] Example 20

[0120] (1) Short-cut viscose-based carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1-3 mm are dispersed in water, and phenolic resin and polyacrylamide are added sequentially. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5-7% of the mass of high thermal conductivity carbon fibers. (2) Divide dispersion I into 5 equal parts and dispersion II into 4 equal parts. Pour three parts of dispersion I and two parts of dispersion II into the mold in turn until all dispersion I and dispersion II are poured out. After each part of dispersion I or dispersion II is poured out, perform a pressure filter. Finally, solidify at 150°C for 1 hour. Under an argon atmosphere, raise the temperature to 1000°C at a heating rate of 2°C / min and keep it at that temperature for 2 hours. The argon flow rate is 100 mL / min. This yields 5 layers of heat-insulating fiber and 4 layers of heat-conducting fiber with alternating distribution. The thickness of a single heat-conducting fiber layer is 1 mm, and the total thickness is 15 mm.

[0121] The thermal conductivity of the composite material obtained in Example 20 in the Z direction at room temperature is shown in Table 2.

[0122] Table 2

[0123]

[0124] It should be noted that the directional heat conduction skeleton materials in Examples 11-14 were prepared using the methods of Examples 17-20, and the directional heat conduction skeleton materials in Example 15 were prepared using the method of Example 16; the Z direction of this invention is the in-plane direction.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an ablation-type directional thermally conductive composite material, characterized in that, The preparation method includes the following steps: S1. Phenolic resin, catalyst and solvent are mixed to obtain a precursor solution; the phenolic resin and catalyst account for 15-25% of the mass of the precursor solution; the phenolic resin is a thermosetting phenolic resin; the catalyst is hexamethylenetetramine; the mass ratio of phenolic resin to catalyst is (5-8):

1. S2. The directional thermally conductive framework material is placed in a precursor solution for vacuum impregnation, sol-gel reaction, and drying to obtain the ablation-type directional thermally conductive composite material as an ablation-type heat insulation material; The ablation-type directional thermally conductive composite material has thermal insulation properties along the vertical in-plane direction; The directional heat-conducting skeleton material is composed of at least one alternating layer of heat-insulating fiber and one layer of heat-conducting fiber; the directional heat-conducting skeleton material has one more layer of heat-insulating fiber than the heat-conducting fiber. The preparation method of the directional thermally conductive skeleton material is as follows: (1) Short-cut viscose-based carbon fibers with a length of 1~3mm are dispersed in water, and phenolic resin and polyacrylamide are added in sequence. After being dispersed evenly by a mechanical stirrer, dispersion I is obtained, wherein the mass ratio of viscose-based carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5~7% of the mass of viscose-based carbon fibers; Short-cut high thermal conductivity carbon fibers with a length of 1~3mm are dispersed in water, and phenolic resin and polyacrylamide are added in sequence. After being dispersed evenly by a mechanical stirrer, dispersion II is obtained; wherein the mass ratio of high thermal conductivity carbon fibers to phenolic resin is 1:1, and the mass of polyacrylamide is 5~7% of the mass of high thermal conductivity carbon fibers; (2) Divide dispersion I and dispersion II into several equal portions. Pour each portion of dispersion I and each portion of dispersion II into the mold alternately until all of dispersion I and dispersion II are poured out. After each portion of dispersion I or dispersion II is poured out, perform a pressure filtration. Finally, solidify at 150~160℃ for 1~1.5h. Under an argon atmosphere, raise the temperature to 1000℃ at a heating rate of 2℃ / min and hold for 2h. The argon flow rate is 100mL / min to obtain the directional thermal conductive skeleton material.

2. The preparation method according to claim 1, characterized in that, The directional heat-conducting skeleton material is obtained by integral curing and heat treatment of alternating layers of heat-insulating fiber and heat-conducting fiber.

3. The preparation method according to claim 1, characterized in that, The number of thermally conductive fiber layers in the directional thermally conductive skeleton material is 1 to 4.

4. The preparation method according to claim 1, characterized in that, The number of thermally conductive fiber layers in the directional thermally conductive skeleton material is 1 to 2.

5. The preparation method according to claim 1, characterized in that, The thickness of a single thermally conductive fiber layer is 1~4mm.

6. The preparation method according to claim 1, characterized in that, The vacuum impregnation time is 24~36 hours.

7. The preparation method according to claim 1, characterized in that, The sol-gel reaction is carried out at a temperature of 75-85°C for 48-52 hours.

8. An ablation-type directional thermally conductive composite material, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

Images