Polymer / liquid metal / modifed carbon fiber fabric composite and method of making same

Abstract

This application provides a polymer / liquid metal / modified carbon fiber fabric composite material and its preparation method, belonging to the field of composite material technology. The polymer / liquid metal / modified carbon fiber fabric composite material comprises 30-60 parts of modified carbon fiber fabric, 20-50 parts of a polymer resin composition, and 5-20 parts of magnetic liquid metal. The modified carbon fiber fabric has a three-dimensional woven structure, the magnetic liquid metal is loaded on the surface of the modified carbon fiber fabric, and the polymer resin composition fills the gaps between the modified carbon fiber fabric and the magnetic liquid metal. The three-dimensional woven structure ensures the interlayer mechanical properties of the composite material; the magnetic liquid metal forms a continuous thermally conductive network under magnetic anchoring, significantly improving the vertical thermal conductivity; the polymer resin fills the gaps, further fixing the liquid metal and enhancing the overall structural stability, thus achieving the integrated requirements of excellent interlayer mechanical properties, high thermal conductivity, and structural stability.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a polymer / liquid metal / modified carbon fiber fabric composite material and its preparation method. Background Technology

[0002] With the development of electronic devices towards high power and miniaturization (such as 5G base station chips and new energy vehicle power batteries), and the stringent requirements for thermal control structures in the aerospace field, the demand for integrated structural and thermal conductivity properties of materials is becoming increasingly urgent. Carbon fiber fabric composites, due to their lightweight and high strength, have become a core candidate material in this field, but existing products still face key bottlenecks. To address the poor interlaminar mechanical properties of traditional two-dimensional laminated carbon fiber composites, the industry has widely adopted three-dimensional weaving technology, which interweaves carbon fibers in multiple directions in space to form an integrated network, significantly improving interlaminar shear strength and anti-delamination ability. However, the three-dimensional weaving structure has not solved the problem of poor interlaminar thermal conductivity: on the one hand, carbon fibers only have excellent thermal conductivity in the axial direction (approximately 150~250 W / (m·K)), while heat conduction perpendicular to the fabric plane must proceed along the tortuous fiber weaving trajectory, resulting in high path resistance; on the other hand, there is interfacial contact thermal resistance between adjacent carbon fiber yarns (approximately 10 W / (m·K)). -4 ~10 -3 m 2 Due to their low thermal conductivity (30-400 W / (m·K)) and low melting point (below 30°C), heat is difficult to transfer rapidly between layers, resulting in a vertical thermal conductivity typically below 5 W / (m·K) for materials, which cannot meet the heat dissipation requirements of high-power devices. Liquid metals (such as gallium-based alloys) are ideal fillers for improving the thermal conductivity of composite materials due to their extremely high thermal conductivity (30-400 W / (m·K)) and low melting point (below 30°C). In existing technologies, some solutions attempt to directly fill the gaps between carbon fiber fabrics with liquid metals. However, liquid metals are fluid and have weak interfacial bonding with carbon fibers and polymer resins. Under long-term use or conditions of vibration and temperature cycling, leakage is likely to occur. This can lead to the breakage of the heat conduction network and a decrease in heat dissipation performance, or even contaminate surrounding electronic components or corrode structural parts, severely restricting their engineering applications.

[0003] Currently, the industry has conducted relevant explorations, but all have significant limitations. For example, encapsulating liquid metal with polymer microcapsules and then combining it with carbon fiber fabrics results in increased thermal resistance from the microcapsule wall material, leading to limited improvement in thermal conductivity. Furthermore, the microcapsules are prone to rupture during processing, failing to completely solve the leakage problem. Other researchers have used electroplating and sputtering to deposit metal films (such as copper and aluminum) on the surface of carbon fibers, attempting to construct continuous thermal conductivity pathways. However, the bonding force between the metal film and the carbon fiber is poor, making it prone to detachment during weaving or curing. Moreover, the uniformity of the metal film thickness is difficult to control, hindering effective connection between adjacent carbon fibers and resulting in poor reduction of interfacial thermal resistance. Some studies have added fillers such as carbon nanotubes and graphene to liquid metal to increase its viscosity and reduce leakage. However, the addition of nanofillers reduces the fluidity of the liquid metal, making it difficult to penetrate into the fine pores of the three-dimensional woven fabric. Additionally, the nanofillers tend to agglomerate, failing to form a uniform thermal conductivity network, thus limiting the improvement in thermal conductivity. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides a polymer / liquid metal / modified carbon fiber fabric composite material and its preparation method, aiming to solve the problem that existing carbon fiber fabric composite materials cannot simultaneously achieve the integrated requirements of excellent interlayer mechanical properties, high thermal conductivity and structural stability.

[0005] In a first aspect, this application provides a polymer / liquid metal / modified carbon fiber fabric composite material, wherein the polymer / liquid metal / modified carbon fiber fabric composite material comprises 30-60 parts of modified carbon fiber fabric, 20-50 parts of polymer resin composition and 5-20 parts of magnetic liquid metal; the modified carbon fiber fabric has a three-dimensional woven structure, the magnetic liquid metal is loaded on the surface of the modified carbon fiber fabric, and the polymer resin composition fills the gap between the modified carbon fiber fabric and the magnetic liquid metal.

[0006] As a further improvement of this application, the fiber substrate of the modified carbon fiber fabric is one or more of polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, and viscose-based carbon fiber; the average diameter of the fiber substrate is 5~12μm, and the density is 1.75~1.95g / cm³. 3 .

[0007] As a further improvement to this application, the three-dimensional braided structure includes one of an orthogonal joint structure, an interlocking joint structure, and a multi-axial warp-knitted structure; the areal density of the modified carbon fiber fabric is 120~350 g / m². 2 The thickness is 3~55mm, and the warp and weft yarn density is 12~32 yarns / 10cm.

[0008] As a further improvement of this application, the magnetic liquid metal comprises a low-melting-point metal alloy and magnetic particles; the mass ratio of the low-melting-point metal alloy to the magnetic particles is (80~95):(5~20); the low-melting-point metal alloy is one or more of Ga-In-Sn liquid metal, Ga-In-Zn liquid metal, In-Bi liquid metal, and In-Sn liquid metal; the magnetic particles are one or more of iron, nickel, and iron(III) oxide, with an average particle size of 50~5000 μm.

[0009] As a further improvement of this application, the polymer resin composition is obtained by mixing a polymer resin and a curing agent at a mass ratio of 1:(0.08~1.2); the polymer resin is one or more of epoxy resin, phenolic resin, and polyimide.

[0010] Secondly, this application provides a method for preparing a polymer / liquid metal / modified carbon fiber fabric composite material as described in the first aspect, comprising the following steps: S1. Preparation of modified carbon fiber fabric: Three-dimensional woven carbon fiber fabric is placed in a magnetic precursor solution, and magnetic materials are grown in situ on the surface of carbon fiber. After washing and drying, modified carbon fiber fabric is obtained. S2. Infusion of magnetic liquid metal: The magnetic liquid metal is infiltrated into the modified carbon fiber fabric by vacuum filtration. The magnetic liquid metal is anchored to the surface of the modified carbon fiber and connected to adjacent carbon fibers by magnetic action, resulting in liquid metal / modified carbon fiber fabric. S3. Curing of the composite material: After the polymer resin and curing agent are mixed evenly, they are infiltrated into the liquid metal / modified carbon fiber fabric by vacuum infiltration technology. After curing, a polymer / liquid metal / modified carbon fiber fabric composite material is obtained.

[0011] As a further improvement of this application, the magnetic material on the surface of the modified carbon fiber fabric is ferrite magnetic particles, which are one or more of Fe3O4, CoFe2O4, NiFe2O4, and MnFe2O4; the particle size of the ferrite magnetic particles is 50~500nm.

[0012] As a further improvement of this application, in step S1, the solute in the magnetic material precursor solution is one or more of ferric chloride, cobalt nitrate, nickel chloride, and manganese nitrate; the solvent in the magnetic material precursor solution is one or two of water and ethanol; and the concentration of the precursor solution is 0.01~0.5mol / L.

[0013] As a further improvement of this application, in step S1, the in-situ growth method is a hydrothermal method or a sol-gel method; the reaction temperature of the hydrothermal method is 120~180℃, and the reaction time is 4~8h; the gelation temperature of the sol-gel method is 60~80℃, and the gelation time is 2~4h; the pH value of the reaction in the hydrothermal method and the sol-gel method is 6~8, the calcination temperature is 200~500℃, and the aging time is 2~48h.

[0014] As a further improvement of this application, in step S3, the curing agent includes at least one of amine curing agents, acid anhydride curing agents, and latent curing agents; the curing pressure is 0.1~1.0 MPa, the curing temperature is 120~200℃, and the curing time is 1~8 h.

[0015] The beneficial effects of this application are as follows: This application provides a polymer / liquid metal / modified carbon fiber fabric composite material and its preparation method. The polymer / liquid metal / modified carbon fiber fabric composite material comprises 30-60 parts of modified carbon fiber fabric, 20-50 parts of a polymer resin composition, and 5-20 parts of magnetic liquid metal. The modified carbon fiber fabric has a three-dimensional woven structure, the magnetic liquid metal is loaded onto the surface of the modified carbon fiber fabric, and the polymer resin composition fills the gaps between the modified carbon fiber fabric and the magnetic liquid metal. This application ensures the interlaminar mechanical properties of the composite material through the three-dimensional woven structure; the magnetic liquid metal forms a continuous thermally conductive network under magnetic anchoring, significantly improving the vertical thermal conductivity; the polymer resin composition fills the gaps, further fixing the liquid metal and enhancing the overall structural stability, thus achieving the integrated requirements of excellent interlaminar mechanical properties, high thermal conductivity, and structural stability.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0018] Figure 1 This is a polarized light microscope image of the liquid metal / modified carbon fiber fabric prepared in Example 1.

[0019] Figure 2The image shows a polarized light microscope image of the liquid metal / modified carbon fiber fabric prepared in Comparative Example 1. Detailed Implementation

[0020] The embodiments of the technical solution of this application are described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms “comprising” and “having” and any variations thereof as used herein are for the purpose of describing particular embodiments only and are not intended to limit this application.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] To address the challenge of existing carbon fiber fabric composites simultaneously achieving excellent interlaminar mechanical properties, high thermal conductivity, and structural stability, this application provides a polymer / liquid metal / modified carbon fiber fabric composite material and its preparation method. First, the carbon fiber fabric undergoes magnetization modification. Then, magnetic liquid metal is infiltrated into the modified carbon fiber fabric, anchoring it to the surface of the modified carbon fiber and connecting adjacent carbon fibers through magnetic action. The mixture is then immersed in resin for curing, resulting in the polymer / liquid metal / modified carbon fiber fabric composite material. The three-dimensional braided structure ensures the interlaminar mechanical properties of the composite material; the liquid metal, under magnetic anchoring, forms a continuous thermally conductive network, significantly improving the vertical thermal conductivity; the polymer resin fills the gaps, further fixing the liquid metal and enhancing the overall structural stability.

[0024] In a first aspect, this application provides a polymer / liquid metal / modified carbon fiber fabric composite material, comprising 30-60 parts of modified carbon fiber fabric, 20-50 parts of polymer resin composition, and 5-20 parts of magnetic liquid metal; the modified carbon fiber fabric has a three-dimensional woven structure, the magnetic liquid metal is loaded on the surface of the modified carbon fiber fabric, and the polymer resin composition fills the gap between the modified carbon fiber fabric and the magnetic liquid metal.

[0025] In the technical solution of this application embodiment, the three-dimensional braided structure ensures the interlayer mechanical properties of the composite material; the magnetic liquid metal forms a continuous thermally conductive network under magnetic anchoring, significantly improving the vertical thermal conductivity; the polymer resin fills the gaps, further fixing the magnetic liquid metal and enhancing the overall structural stability. Magnetic particles are grown in situ on the surface of the three-dimensional braided carbon fiber fabric. These magnetic particles not only form a strong interfacial adsorption effect with the magnetic liquid metal (through magnetic attraction and surface wettability), anchoring the liquid metal to the carbon fiber surface and completely solving the leakage problem; they also act as bridges, connecting adjacent carbon fibers and eliminating interfacial thermal resistance between yarns.

[0026] Furthermore, in some embodiments, the fiber substrate of the modified carbon fiber fabric is one or more of polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, and viscose-based carbon fiber; the average diameter of the fiber substrate is 5~12μm, and the density is 1.75~1.95g / cm³. 3 .

[0027] In the technical solution of this application embodiment, polyacrylonitrile-based carbon fiber combines high strength, high modulus, and good processing adaptability, making it the most widely used carbon fiber substrate currently, suitable for most electronic devices and structural components. Pitch-based carbon fiber has higher thermal conductivity and cost advantages, making it suitable for scenarios with extremely high thermal conductivity requirements. Viscose-based carbon fiber has excellent corrosion resistance and biocompatibility, extending its application to special environments. The average diameter of the carbon fiber is controlled between 5 and 12 μm, a range that ensures both the mechanical strength of the fiber and allows the fiber bundle to form a suitable interstitial structure, facilitating the penetration and anchoring of magnetic liquid metals; the density is 1.75~1.95 g / cm³. 3 This ensures the lightweight properties of the composite material.

[0028] Furthermore, in some embodiments, the three-dimensional braided structure includes one of the following: an orthogonal joint structure, an interlocking joint structure, and a multi-axial warp-knitted structure; the areal density of the modified carbon fiber fabric is 120~350 g / m². 2 The thickness is 3~55mm, and the warp and weft yarn density is 12~32 yarns / 10cm.

[0029] In the technical solution of this application embodiment, the three-dimensional woven structure forms a spatial network skeleton by interweaving and locking carbon fiber bundles in the X, Y, and Z directions, fundamentally solving the problem of weak interlayer bonding in traditional two-dimensional laminated composite materials. It can ensure the structural support strength while avoiding excessive fiber density that hinders the penetration of liquid metal. The areal density and warp and weft yarn density range can meet the differentiated needs of material lightweighting and structural strength in different scenarios. By controlling the tightness of the fiber bundles, the mechanical properties and the penetration efficiency of liquid metal are balanced.

[0030] Furthermore, in some embodiments, the magnetic liquid metal comprises a low-melting-point metal alloy and magnetic particles; the mass ratio of the low-melting-point metal alloy to the magnetic particles is (80~95):(5~20); the low-melting-point metal alloy is one or more of Ga-In-Sn liquid metal, Ga-In-Zn liquid metal, In-Bi liquid metal, and In-Sn liquid metal; the magnetic particles are one or more of iron, nickel, and iron(III) oxide, with an average particle size of 50~5000 μm.

[0031] In the technical solution of this application embodiment, the magnetic liquid metal can be anchored to the surface of the carbon fiber under the action of magnetic particles, acting as a bridge to connect adjacent carbon fibers and eliminate the interfacial thermal resistance between yarns.

[0032] Furthermore, in some embodiments, the polymer resin composition is obtained by mixing a polymer resin and a curing agent at a mass ratio of 1:(0.08~1.2); the polymer resin is one or more of epoxy resin, phenolic resin, and polyimide.

[0033] In the technical solution of this application embodiment, polymer resin fills the gaps to further fix the liquid metal and enhance the overall structural stability.

[0034] Secondly, this application provides a method for preparing a polymer / liquid metal / modified carbon fiber fabric composite material, comprising the following steps: S1. Preparation of modified carbon fiber fabric: Three-dimensional woven carbon fiber fabric is placed in a magnetic precursor solution, and magnetic materials are grown in situ on the surface of carbon fiber. After washing and drying, modified carbon fiber fabric is obtained. S2. Infusion of magnetic liquid metal: The magnetic liquid metal is infiltrated into the modified carbon fiber fabric by vacuum filtration. The magnetic liquid metal is anchored to the surface of the modified carbon fiber and connected to adjacent carbon fibers by magnetic action, resulting in liquid metal / modified carbon fiber fabric. S3. Curing of composite materials: After the polymer resin and curing agent are mixed evenly, they are infiltrated into liquid metal / modified carbon fiber fabric by vacuum infiltration technology. After curing, polymer / liquid metal / modified carbon fiber fabric composite material is obtained.

[0035] In the technical solution of this application embodiment, carbon fiber fabric is first magnetized and modified, then magnetic liquid metal is infiltrated into the modified carbon fiber fabric, allowing the liquid metal to be anchored to the surface of the modified carbon fiber and connect adjacent carbon fibers through magnetic action. Then, it is immersed in resin for curing to obtain a polymer / liquid metal / modified carbon fiber fabric composite material. The three-dimensional braided structure ensures the interlayer mechanical properties of the composite material; the liquid metal forms a continuous thermally conductive network under magnetic anchoring, significantly improving the vertical thermal conductivity; the polymer resin fills the gaps, further fixing the liquid metal and enhancing the overall structural stability.

[0036] Furthermore, in some embodiments, the magnetic material on the surface of the modified carbon fiber fabric is ferrite magnetic particles, which are one or more of Fe3O4, CoFe2O4, NiFe2O4, and MnFe2O4; the particle size of the ferrite magnetic particles is 50~500nm.

[0037] In the technical solution of this application embodiment, the magnetic particles can not only form a strong interfacial adsorption effect with the liquid metal (through magnetic attraction and surface wettability), anchoring the liquid metal to the carbon fiber surface and completely solving the leakage problem; they can also act as a bridge, connecting the liquid metal to adjacent carbon fibers and eliminating the interfacial thermal resistance between yarns.

[0038] Furthermore, in some embodiments, in step S1, the solute in the magnetic material precursor solution is one or more of ferric chloride, cobalt nitrate, nickel chloride, and manganese nitrate; the solvent in the magnetic material precursor solution is one or two of water and ethanol; and the concentration of the precursor solution is 0.01~0.5 mol / L.

[0039] In the technical solution of this application embodiment, the precursor can grow magnetic materials of appropriate density on the carbon fiber surface, which facilitates the uniform and stable anchoring of subsequent liquid metal.

[0040] Furthermore, in some embodiments, in step S1, the in-situ growth method is a hydrothermal method or a sol-gel method; the reaction temperature of the hydrothermal method is 120~180℃, and the reaction time is 4~8h; the gelation temperature of the sol-gel method is 60~80℃, and the gelation time is 2~4h; the pH value of the reaction in the hydrothermal method and the sol-gel method is 6~8, the calcination temperature is 200~500℃, and the aging time is 2~48h.

[0041] In the technical solution of this application embodiment, specific reaction conditions are used to uniformly grow magnetic materials on the surface of carbon fibers, and the particle size of the magnetic materials is 50~500nm, ensuring that the magnetic particles form a strong bond with the carbon fibers and are not easy to fall off during subsequent processing and use.

[0042] Furthermore, in some embodiments, in step S2, vacuum filtration specifically includes the following steps: evacuating to an absolute pressure of less than 25 kPa, injecting magnetic liquid metal preheated to 40~70°C, and holding at that temperature for 10~30 min.

[0043] Furthermore, in some embodiments, in step S3, the curing agent includes at least one of amine curing agents, acid anhydride curing agents, and latent curing agents; the curing pressure is 0.1~1.0 MPa, the curing temperature is 120~200℃, and the curing time is 1~8h.

[0044] Furthermore, the curing process employs a segmented heating curing method, which includes the following steps: first, maintaining the temperature at 125~140℃ for 1~3 hours, and then raising the temperature to 160~185℃ and maintaining it for 1~6 hours.

[0045] Furthermore, in some embodiments, in step S3, the absolute pressure of vacuum permeation is less than 30 kPa.

[0046] In the technical solution of this application embodiment, under these conditions, the polymer resin can be fully penetrated, and the stability of the overall structure can be enhanced.

[0047] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0048] Example 1 This embodiment provides a method for preparing a polymer / liquid metal / modified carbon fiber fabric composite material, specifically including the following steps: S1. Preparation of modified carbon fiber fabric: A corner interlocking structure fabric woven from polyacrylonitrile-based carbon fibers (area density of 200 g / m²) was selected. 2 The modified carbon fiber fabric (with a thickness of 10 mm and a warp and weft yarn density of 20 yarns / 10 cm) was soaked in a mixed aqueous solution of 0.3 mol / L FeCl3 and placed in a hydrothermal reactor at 150 °C for 6 h. After the reaction, it was washed and dried to obtain a modified carbon fiber fabric with Fe3O4 particles (particle size 100 nm, coverage rate 80%) on the surface. S2. Injection of magnetic liquid metal: 45 parts by mass of modified carbon fiber fabric were placed in a mold, and a vacuum was drawn to an absolute pressure of 20 kPa. 10 parts by mass of magnetic liquid metal at 45°C were injected and kept at this temperature for 20 min to obtain liquid metal / modified carbon fiber fabric. The magnetic liquid metal was obtained by mixing Ga-In-Sn liquid metal and iron particles at a mass ratio of 90:10. S3. Curing of composite material: Epoxy resin E-51 and ethylenediamine are mixed evenly at a mass ratio of 1:1 (total mass parts 45 parts), and injected into liquid metal / modified carbon fiber fabric at 25 kPa. A pressure of 0.5 MPa is applied, and the mixture is kept at 130℃ for 2 hours, and then kept at 170℃ for 3 hours to obtain polymer / liquid metal / modified carbon fiber fabric composite material.

[0049] The polarized light microscope image of the liquid metal / modified carbon fiber fabric prepared in this embodiment is shown below. Figure 1As shown, it can be seen that carbon fibers loaded with 100nm magnetite magnetic particles have a good anchoring effect on liquid metal, which significantly reduces the interfacial thermal resistance between the fibers and enhances thermal conductivity.

[0050] Examples 2-3 and Comparative Examples 1-2 Examples 2-3 and Comparative Examples 1-2 each provide a method for preparing a polymer / liquid metal / modified carbon fiber fabric composite material. The difference compared to Example 1 lies in the particle size of the Fe3O4 particles, as detailed in Table 1. Other steps are largely the same as in Example 1 and will not be repeated here. The temperature range for the 1000 temperature cycling tests is -55℃ to 150℃.

[0051] Table 1. Particle size of Fe3O4 particles and performance results of composite materials in Examples 1-3 and Comparative Examples 1-2. As can be seen from the results of Examples 1-3 and Comparative Examples 1-2 in Table 1, when the particle size is 100 nm (Example 1), the dispersibility and magnetic anchoring effect of the magnetic particles are balanced, and the thermal conductivity is optimal. When the particle size is too small (30 nm), the magnetic particles are prone to agglomeration, the "bridge" effect of liquid metal connecting adjacent carbon fibers is weakened, the thermal conductivity decreases and the leakage rate increases. When the particle size is too large (600 nm), the particles will hinder the penetration of liquid metal, and the surface coverage of carbon fibers is uneven, resulting in an increase in volume resistivity and a thermal conductivity slightly lower than the optimal value. However, the physical anchoring effect of large particles can reduce the leakage rate. Therefore, when the particle size of Fe3O4 particles is in the range of 50-500 nm, the dispersibility and magnetic anchoring effect of the magnetic particles are relatively balanced, and the performance is better. Figure 2 The image shown is a polarized light microscope image of the liquid metal / modified carbon fiber fabric prepared in Comparative Example 1. It can be seen that due to the small particle size, the "bridge" effect of the liquid metal connecting adjacent carbon fibers is weakened, resulting in a significant increase in leakage rate and a decrease in coverage.

[0052] Examples 4-5 and Comparative Examples 3-4 Examples 4-5 and Comparative Examples 3-4 respectively provide a method for preparing a polymer / liquid metal / modified carbon fiber fabric composite material. The difference from Example 1 is that the concentration of FeCl3 is different, as shown in Table 2. The other steps are roughly the same as in Example 1, and will not be repeated here.

[0053] Table 2. Results of FeCl3 concentration and composite material performance in Examples 1, 4-5 and Comparative Examples 3-4. As can be seen from the results in Examples 1, 4-5 and Comparative Examples 3-4 in Table 2, when the concentration is 0.3 mol / L (Example 1), the growth density of magnetic particles on the carbon fiber surface is moderate, which can form effective magnetic anchoring without clogging the pores, resulting in the best overall performance. If the concentration is too low (0.005 mol / L), the magnetic particle coverage is insufficient, the liquid metal anchoring force is weak, the leakage rate increases significantly, and the thermal conductivity network becomes discontinuous. If the concentration is too high (0.6 mol / L), excessive growth of magnetic particles will clog the fabric pores, the liquid metal penetration will be insufficient, and both thermal conductivity and resistivity will decrease. Therefore, when the concentration of the precursor ferric chloride is in the range of 0.01~0.5 mol / L, the composite material exhibits high thermal conductivity while maintaining low volume resistivity and low liquid metal content.

[0054] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A polymer / liquid metal / modified carbon fiber fabric composite material, characterized in that, The polymer / liquid metal / modified carbon fiber fabric composite material comprises 30-60 parts of modified carbon fiber fabric, 20-50 parts of polymer resin composition and 5-20 parts of magnetic liquid metal; The modified carbon fiber fabric has a three-dimensional woven structure, the magnetic liquid metal is loaded on the surface of the modified carbon fiber fabric, and the polymer resin composition fills the gap between the modified carbon fiber fabric and the magnetic liquid metal.

2. The polymer / liquid metal / modified carbon fiber fabric composite material according to claim 1, characterized in that, The modified carbon fiber fabric uses one or more of polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, and viscose-based carbon fiber as its fiber substrate; the average diameter of the fiber substrate is 5~12μm, and its density is 1.75~1.95g / cm³. 3 .

3. The polymer / liquid metal / modified carbon fiber fabric composite material according to claim 1, characterized in that, The three-dimensional braided structure includes one of the following: orthogonal joint structure, corner interlocking joint structure, and multi-axial warp knitting structure; the areal density of the modified carbon fiber fabric is 120~350 g / m². 2 The thickness is 3~55mm, and the warp and weft yarn density is 12~32 yarns / 10cm.

4. The polymer / liquid metal / modified carbon fiber fabric composite material according to claim 1, characterized in that, The magnetic liquid metal comprises a low-melting-point metal alloy and magnetic particles; the mass ratio of the low-melting-point metal alloy to the magnetic particles is (80~95):(5~20); the low-melting-point metal alloy is one or more of Ga-In-Sn liquid metal, Ga-In-Zn liquid metal, In-Bi liquid metal, and In-Sn liquid metal; the magnetic particles are one or more of iron, nickel, and iron(III) oxide, with an average particle size of 50~5000μm.

5. The polymer / liquid metal / modified carbon fiber fabric composite material according to claim 1, characterized in that, The polymer resin composition is obtained by mixing a polymer resin and a curing agent at a mass ratio of 1:(0.08~1.2); the polymer resin is one or more of epoxy resin, phenolic resin, and polyimide.

6. A method for preparing a polymer / liquid metal / modified carbon fiber fabric composite material as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Preparation of modified carbon fiber fabric: Three-dimensional woven carbon fiber fabric is placed in a magnetic precursor solution, and magnetic materials are grown in situ on the surface of carbon fiber. After washing and drying, modified carbon fiber fabric is obtained. S2. Infusion of magnetic liquid metal: The magnetic liquid metal is infiltrated into the modified carbon fiber fabric by vacuum filtration. The magnetic liquid metal is anchored to the surface of the modified carbon fiber and connected to adjacent carbon fibers by magnetic action, resulting in liquid metal / modified carbon fiber fabric. S3. Curing of the composite material: After the polymer resin and curing agent are mixed evenly, they are infiltrated into the liquid metal / modified carbon fiber fabric by vacuum infiltration technology. After curing, a polymer / liquid metal / modified carbon fiber fabric composite material is obtained.

7. The method for preparing the polymer / liquid metal / modified carbon fiber fabric composite material according to claim 6, characterized in that, The magnetic material on the surface of the modified carbon fiber fabric is ferrite magnetic particles, which are one or more of Fe3O4, CoFe2O4, NiFe2O4, and MnFe2O4; the particle size of the ferrite magnetic particles is 50~500nm.

8. The method for preparing the polymer / liquid metal / modified carbon fiber fabric composite material according to claim 6, characterized in that, In step S1, the solute in the magnetic material precursor solution is one or more of ferric chloride, cobalt nitrate, nickel chloride, and manganese nitrate; the solvent in the magnetic material precursor solution is one or two of water and ethanol; and the concentration of the precursor solution is 0.01~0.5 mol / L.

9. The method for preparing the polymer / liquid metal / modified carbon fiber fabric composite material according to claim 6, characterized in that, In step S1, the in-situ growth method is either hydrothermal or sol-gel; the reaction temperature of the hydrothermal method is 120~180℃, and the reaction time is 4~8h; the gelation temperature of the sol-gel method is 60~80℃, and the gelation time is 2~4h; the pH value of the reaction in the hydrothermal and sol-gel methods is 6~8, the calcination temperature is 200~500℃, and the aging time is 2~48h.

10. The method for preparing the polymer / liquid metal / modified carbon fiber fabric composite material according to claim 6, characterized in that, In step S3, the curing agent includes at least one of amine curing agents, acid anhydride curing agents, and latent curing agents; the curing pressure is 0.1~1.0 MPa, the curing temperature is 120~200℃, and the curing time is 1~8 h.

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