A three-dimensional fabric reinforcement, a method for making the same and a polymer matrix composite

Abstract

The present application relates to the technical field of heat-conducting functional composite materials, in particular to a three-dimensional fabric reinforcement, a preparation method thereof and a polymer-based composite material. The three-dimensional fabric reinforcement provided by the present application has a three-way orthogonal structure, wherein the in-plane is X direction and Y direction, and the thickness is Z direction, and the X direction, Y direction and Z direction all have continuous fiber distribution; the Z direction uses Z-directional fibers coated with a polymer layer; the carbon fibers include mesophase pitch-based carbon fibers and / or high model polyacrylonitrile carbon fibers. The present application coats the surface of the carbon fibers with a polymer layer, which can increase the toughness of the carbon fibers, solve the problem of easy broken yarn and fuzz in the weaving process of high model carbon fibers, ensure the continuity of the carbon fibers and efficient conversion of the heat-conducting and electric-conducting properties when preparing the composite material; the three-dimensional fabric reinforcement is used as a preform to prepare a polymer-based composite material, and the heat-conducting and electric-conducting properties in the thickness direction and the interlayer performance are obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat-conducting functional composite materials, and particularly relates to a three-dimensional fabric reinforcing body, a preparation method thereof and a polymer-based composite material. BACKGROUND

[0002] Fiber composite materials have been widely used in the fields of aerospace, transportation, electronics and wind turbine blades due to their advantages of light weight, high strength, designability, corrosion resistance, fatigue resistance and structural-function integration. Continuous fiber composite materials are a typical representative of advanced composite materials. Traditional fiber composite materials are usually prepared by a multi-layer stacking method using one-dimensional or two-dimensional fabrics as reinforcing bodies. Since this stacking method lacks effective fiber reinforcement between layers, the prepared composite materials have poor heat-conducting and electric-conducting properties in the thickness direction and poor interlayer performance.

[0003] For polymer-based composite materials, the heat conduction of the matrix is mainly through lattice vibration, and the thermal conductivity is very low. Therefore, the key to improving the heat-conducting performance of polymer-based composite materials lies in the number of heat-conducting channels formed in the matrix and the stability of the heat-conducting channels. Adding fillers to the matrix can improve the heat-conducting capacity of polymer-based composite materials to a certain extent, but the fillers are usually in the form of particles, and the particles cannot fully contact each other. When heat is transferred, the heat-conducting channels are chaotic, and the desired effect cannot be achieved.

[0004] High-thermal-conducting fibers, as one-dimensional high-thermal-conducting materials, can overcome the shortcomings of particle fillers by penetrating through continuous fibers with high thermal conductivity in the thickness direction of polymer-based composite materials, and the heat-conducting performance in the thickness direction and the interlayer performance are significantly improved. High-modulus carbon fibers have a relatively perfect crystal structure and a high degree of graphitization, and therefore have excellent electric-conducting and heat-conducting properties. However, high-modulus carbon fibers are brittle and are easily damaged during weaving, which limits their application in high-thermal-conducting polymer-based composite materials. SUMMARY

[0005] The present application aims to provide a three-dimensional fabric reinforcing body, a preparation method thereof and a polymer-based composite material. The three-dimensional fabric reinforcing body provided by the present application is coated with a polymer layer on the surface of carbon fibers, which can solve the problem of broken filaments and fuzzing during the weaving process of high-modulus carbon fibers, and will not affect the overall heat-conducting and electric-conducting performance of the carbon fibers. The three-dimensional fabric reinforcing body is used as a preform to prepare a polymer-based composite material, and the heat-conducting, electric-conducting performance in the thickness direction and the interlayer performance of the polymer-based composite material are significantly improved.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] The application provides a three-dimensional fabric reinforcement body with a three-way orthogonal structure, wherein the in-plane is X direction and Y direction, the thickness is Z direction, the X direction, Y direction and Z direction all have continuous fiber distribution; the Z direction uses Z direction fiber coated with a polymer layer; the carbon fiber includes mesophase pitch-based carbon fiber and / or high model polyacrylonitrile carbon fiber.

[0008] Preferably, the volume fraction of the X direction fiber and Y direction fiber in the three-dimensional fabric reinforcement body is independently 35-45%, and the volume fraction of the Z direction fiber is 15-30%.

[0009] Preferably, the specification of the carbon fiber is 1-24K.

[0010] Preferably, the polymer used in the polymer layer includes polyvinyl alcohol, polyurethane, polyacrylonitrile or polyphenylene sulfide resin.

[0011] Preferably, the thickness of the polymer layer is 0.1-0.5mm.

[0012] Preferably, the preparation method of the Z direction fiber includes the following steps:

[0013] The mixture containing the polymer used in the polymer layer and the organic solvent is coated on the surface of the carbon fiber, and after removing the organic solvent, the polymer layer is formed on the surface of the carbon fiber to obtain the Z direction fiber.

[0014] Preferably, the X direction fiber used in the X direction and the Y direction fiber used in the Y direction independently include one or more of carbon fiber, basalt fiber, glass fiber and aramid fiber; the specification of the X direction fiber and Y direction fiber is independently 1-24K.

[0015] Preferably, the number of layers of the three-dimensional fabric reinforcement body is 2-5 layers, the single layer thickness is 1-5mm, and the layer spacing is 5-10mm.

[0016] The application provides a preparation method of the three-dimensional fabric reinforcement body described in the above technical solution, including the following steps:

[0017] The X direction fiber used in the X direction, the Y direction fiber used in the Y direction and the Z direction fiber used in the Z direction are provided;

[0018] The X direction fiber and Y direction fiber are woven to form orthogonal layers, and the Z direction fiber penetrates the thickness direction of several orthogonal layers to obtain a three-dimensional fabric reinforcement body.

[0019] The application provides a polymer matrix composite material, and the three-dimensional fabric reinforcement body described in the above technical solution or the three-dimensional fabric reinforcement body prepared by the preparation method described in the above technical solution is a preform.

[0020] The application provides a three-dimensional fabric reinforcement body with a three-way orthogonal structure, wherein the in-plane is an X direction and a Y direction, and the thickness is a Z direction, the X direction, the Y direction and the Z direction all have continuous fiber distribution; the Z direction uses Z-direction fibers coated with a polymer layer; the carbon fibers include mesophase pitch-based carbon fibers and / or high model polyacrylonitrile carbon fibers. -1 ·K -1 The mesophase pitch-based carbon fibers and the high model polyacrylonitrile carbon fibers are high model carbon fibers, have high thermal conductivity and high electrical conductivity, the thermal conductivity is greater than 100 W·m BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a structure schematic diagram of the three-dimensional fabric reinforcement body;

[0022] Figure 2 It is a cross-sectional schematic diagram of the three-dimensional fabric reinforcement body;

[0023] Figure 3 It is a flowchart of coating the surface of the carbon fibers by using an impregnation method;

[0024] Figure 4 It is a flowchart of coating the surface of the carbon fibers by using a spraying method;

[0025] Figure 5 It is a structure schematic diagram of the three-dimensional fabric reinforcement body in the polymer matrix composite material. DETAILED DESCRIPTION

[0026] In the application, the X direction, the Y direction and the Z direction only represent the relative position relationship of the fibers, and have no other special limiting effect.

[0027] The application provides a three-dimensional fabric reinforcement body (the structure schematic diagram of the three-dimensional fabric reinforcement body is shown in FIG. 1), Figure 1 It is a structure schematic diagram of the three-dimensional fabric reinforcement body; Figure 2 It is a cross-sectional schematic diagram of the three-dimensional fabric reinforcement body), with a three-way orthogonal structure, wherein the in-plane is an X direction and a Y direction, and the thickness is a Z direction, the X direction, the Y direction and the Z direction all have continuous fiber distribution; the Z direction uses Z-direction fibers coated with a polymer layer; the carbon fibers include mesophase pitch-based carbon fibers and / or high model polyacrylonitrile carbon fibers.

[0028] In the present application, the high model polyacrylonitrile carbon fiber is preferably high model polyacrylonitrile carbon fiber M55J or M40J. In the present application, the mesophase pitch-based carbon fiber and the high model polyacrylonitrile carbon fiber are high model carbon fibers, which have high thermal conductivity and high electrical conductivity, with a thermal conductivity greater than 100 W·m -1 ·K -1 , an electrical conductivity greater than 100 S / cm, which can ensure that the polymer matrix composite with a three-dimensional fabric reinforcement as a preform has high electrical conductivity and high thermal conductivity in the Z direction; the surface of the carbon fiber is coated with a polymer layer, which can increase the toughness of the carbon fiber, solve the problem of easy breaking and fuzzing during weaving of the high model carbon fiber, and ensure the continuity of the carbon fiber and efficient conversion of the thermal and electrical conductivity of the composite material.

[0029] In the present application, the volume fraction of the X-direction fibers and the Y-direction fibers in the three-dimensional fabric reinforcement is preferably 35-45%, more preferably 35-40%; wherein the volume fraction of the X-direction fibers and the Y-direction fibers can be the same or different, and when the volume fraction of the X-direction fibers and the Y-direction fibers is different, the difference between the volume fraction of the X-direction fibers and the Y-direction fibers is preferably ≤5%. In the present application, the volume fraction of the Z-direction fibers in the three-dimensional fabric reinforcement is preferably 15-30%, more preferably 15-20%.

[0030] In the present application, the specification of the carbon fiber in the Z-direction fiber is preferably 1-24K, more preferably 3-6K; the diameter of the carbon fiber is preferably 5-11 μm, more preferably 7-9 μm.

[0031] In the present application, the polymer used in the polymer layer of the Z-direction fiber preferably includes polyvinyl alcohol, polyurethane, polyacrylonitrile, or polyphenylene sulfide resin. The present application does not have special limitations on the source of the polymer, and commercially available products or preparation methods known to those skilled in the art can be used. In the present application, the thickness of the polymer layer is preferably 0.1-0.5 mm, more preferably 0.2-0.4 mm. By selecting a suitable polymer and controlling the thickness of the polymer layer, the present application reduces the residual stress generated during preparation, which causes the carbon fiber to be bent, the matrix to be damaged, and the mechanical properties of the composite material to be reduced, and can ensure that the high model carbon fiber has strong toughness without affecting its overall thermal and electrical conductivity.

[0032] In the present application, the preparation method of the Z-direction fiber preferably includes the following steps:

[0033] The mixture containing the polymer used for the polymer layer and the organic solvent is coated on the surface of the carbon fiber, and after the organic solvent is removed, a polymer layer is formed on the surface of the carbon fiber, thereby obtaining a Z-direction fiber.

[0034] The application preferably first provides a mixture containing the polymer used for the polymer layer and the organic solvent. In the application, the mixture can be directly obtained by mixing the polymer and the organic solvent, or other chemical substances such as plasticizers can be added according to the characteristics of the polymer, and the application does not make special limitations on this. In the application, the mass fraction of the polymer in the mixture is preferably 5-25%, and more preferably 5-20%; the application preferably selects a suitable organic solvent according to the specific type of the polymer, and selects a suitable ratio of the two. In the embodiments of the application, the specific:

[0035] When the polymer is polyacrylonitrile, dimethyl sulfoxide is preferably used as the solvent, and the polyacrylonitrile is mixed with dimethyl sulfoxide to prepare a polyacrylonitrile solution (i.e. the mixture), wherein the mass fraction of the polyacrylonitrile in the polyacrylonitrile solution is preferably 10-20%;

[0036] When the polymer is polyvinyl alcohol, polyvinyl alcohol particles are preferably added in warm water at 25-35℃, and stirred at a speed of 200-300 r / min for 1-2 h; after the polyvinyl alcohol particles are fully water-swollen, the temperature is increased to 90-95℃, and the stirring is continued for 3-4 h; after cooling to room temperature, ethanol is added and the stirring is continued for 1-2 h, thereby obtaining a polyvinyl alcohol solution (i.e. the mixture); wherein the mass fraction of the polyvinyl alcohol in the polyvinyl alcohol solution is preferably 4-7%, and the volume ratio of water to ethanol in the polyvinyl alcohol solution is preferably 1:(0.8-1.2);

[0037] When the polymer is polyphenylene sulfide resin, the polyphenylene sulfide resin and industrial alcohol are preferably mixed, and then ball-milled to a particle size of less than 120 μm, thereby obtaining a suspension (i.e. the mixture), wherein the mass fraction of the polyphenylene sulfide resin in the suspension is preferably 20-25%.

[0038] After obtaining the mixture, the present invention preferably coats the mixture onto the surface of carbon fibers, removes the organic solvent, and forms a polymer layer on the surface of the carbon fibers to obtain Z-axis fibers. The present invention does not have a specific limitation on the coating method; a coating method well-known to those skilled in the art can be used based on the polymer's solubility and melting temperature. The present invention preferably uses an impregnation method or a spraying method. The present invention does not have a specific limitation on the specific operation method of the impregnation method or the spraying method, as long as a uniform polymer layer with the required thickness is obtained. The present invention does not have a specific limitation on the specific method or conditions for removing the organic solvent, as long as the formed polymer layer has strong toughness and stability and does not crack or age easily. In an embodiment of the present invention, a flowchart of the impregnation method for coating the carbon fiber surface is shown below. Figure 3 As shown, specifically, the mixture is placed in an impregnation tank to impregnate the fibers, and then the solvent is evaporated in a drying oven (preferably at a temperature of 75-80°C). The flowchart for coating the carbon fiber surface using a spraying method is shown below. Figure 4 As shown, the mixture is placed in a spray gun and sprayed in a spray chamber, then the solvent is evaporated in a drying oven (preferably at 75-80°C). In this invention, the take-up roller speed is preferably controlled at 0.1-0.2 m / min during the coating process. Furthermore, in this invention, to obtain a uniform polymer layer with the required thickness, multiple coatings can be applied as needed, specifically, the next layer is applied as soon as the previous layer dries, thus ensuring strong adhesion between the coatings.

[0039] In this invention, the X-direction fibers used in the X direction and the Y-direction fibers used in the Y direction preferably independently include one or more of carbon fiber, basalt fiber, glass fiber, and aramid fiber, more preferably independently of carbon fiber, basalt fiber, glass fiber, or aramid fiber, and even more preferably carbon fiber. In this invention, the carbon fibers in the X-direction and Y-direction fibers can be high-modulus carbon fibers (such as mesophase pitch-based carbon fibers or high-modulus polyacrylonitrile carbon fibers) or non-high-modulus carbon fibers (such as high-strength polyacrylonitrile carbon fibers T300, T700, or T800); when the carbon fibers in the X-direction and Y-direction fibers are high-modulus carbon fibers, this invention preferably coats the surface of the high-modulus carbon fibers with a polymer layer; wherein, the range of polymers used in the polymer layer of the X-direction and Y-direction fibers is preferably consistent with the range of polymers used in the polymer layer of the Z-direction fibers, and will not be repeated here; the preparation method of the polymer layer in the X-direction and Y-direction fibers is preferably consistent with the preparation method of the polymer layer in the Z-direction fibers, and will not be repeated here. In this invention, the specifications of the X-axis fiber and the Y-axis fiber are preferably 1 to 24K, more preferably 3 to 6K; the diameter of the X-axis fiber and the Y-axis fiber is preferably 5 to 11 μm, more preferably 7 to 9 μm.

[0040] In the present application, the number of layers of the three-dimensional fabric reinforcement (wherein the orthogonal layup formed by the X-direction fibers and the Y-direction fibers is one layer) is preferably 2-5 layers, more preferably 3-4 layers; the thickness of a single layer is preferably 1-5 mm, more preferably 2-4 mm; the interlayer spacing is preferably 5-10 mm, more preferably 6-9 mm; the orthogonal layups in the present application are connected by Z-direction fibers, and the interlayer spacing specifically refers to the length of the Z-direction fibers between adjacent orthogonal layups.

[0041] The present application provides a preparation method of the three-dimensional fabric reinforcement described in the above technical solution, comprising the following steps:

[0042] providing X-direction X-direction fibers, Y-direction Y-direction fibers and Z-direction Z-direction fibers;

[0043] weaving the X-direction fibers and the Y-direction fibers to form an orthogonal layup, while the Z-direction fibers penetrate the thickness direction of several orthogonal layups to obtain a three-dimensional fabric reinforcement.

[0044] In the present application, the Z-direction fibers serve as the stitching yarn of the three-dimensional fabric reinforcement, which can realize the connection between multiple orthogonal layups; in actual use, the appropriate number of orthogonal layup layers can be determined according to the thickness of the required three-dimensional fabric reinforcement, and then the stitching yarn (i.e. the Z-direction fibers) between the multiple orthogonal layup layers is cut off, and then compressed to obtain a three-dimensional fabric reinforcement with the required thickness.

[0045] The present application provides a polymer matrix composite, wherein the three-dimensional fabric reinforcement prepared by the above technical scheme or the preparation method is a preform. In the present application, the resin matrix system used by the polymer matrix composite comprises resin material and diluent, and curing agent or catalyst can also be added according to actual needs; the present application does not have special limitations on the types and ratio of the resin material, diluent, curing agent and catalyst, and the technical scheme well known to those skilled in the art can be used. In the present application, the resin material preferably comprises epoxy resin, cyanate ester resin, phenolic resin or bismaleimide resin, more preferably epoxy resin or cyanate ester resin, and the epoxy resin is preferably epoxy resin E51; the viscosity of the resin material is preferably less than 0.5 Pa·s, more preferably 0.2-0.3 Pa·s; the diluent preferably comprises polyethylene glycol diglycidyl ether (PEGDGE), butyl glycidyl ether (BGE, active diluent 501) or dibutyl phthalate; the curing agent preferably comprises triethylenetetramine or phthalic anhydride; and the catalyst preferably comprises triethylamine. In the present application, the molar ratio of the resin material and diluent is preferably 100:(5-30), more preferably 100:(10-25); the mass ratio of the resin material and curing agent is preferably 100:(10-80), more preferably 100:(10-60); and the mass ratio of the resin material and catalyst is preferably 100:(3-5). The present application does not have special limitations on the preparation method of the resin matrix system, and the components can be directly stirred and mixed uniformly.

[0046] The present application does not have special limitations on the preparation method of the polymer matrix composite, and the preparation method well known to those skilled in the art can be used. The present application preferably places the three-dimensional fabric reinforcement in a mold, uses the resin transfer molding (RTM) process at room temperature, and uses an injection machine to inject the resin matrix system; after injection, it is placed in an oven for curing; after demolding, it is polished to obtain a polymer matrix composite.

[0047] In the present application, the volume ratio of the resin matrix system to the three-dimensional fabric reinforcement is preferably 4:(5-7), more preferably 4:6.

[0048] In the present application, during the injection process, the injection pressure is preferably 0.5-1.5 MPa, more preferably 0.6-1.0 MPa.

[0049] In the present application, the temperature of the curing is preferably 90-250°C, and the time is preferably 6-20h; in the embodiments of the present application, the temperature and time of the curing are specifically selected according to the composition of the resin matrix system, when the resin material used is an epoxy resin, it is preferred to be cured at 90-100°C for 3-4h, and then continue to be cured at 120-130°C for 3-4h; when the resin material used is a cyanate ester resin, it is preferred to be cured at 145-155°C for 4-5h, and then continue to be cured at 180-185°C for 2-3h, at 200-205°C for 2-3h, at 220-225°C for 2-3h, and at 240-245°C for 4-5h, respectively.

[0050] In the present application, it is preferred to polish the upper and lower surfaces of the composite material obtained after demolding by using sandpaper, and the specifications of the sandpaper are preferably 400 mesh, 800 mesh, 1000 mesh and 2000 mesh, respectively, until the Z-direction fiber end (as shown in Figure 5 The upper and lower surfaces of the composite material are parallel and the thickness direction is perpendicular to the horizontal plane, and the Z-direction fibers are generally kept in a vertical continuous state, so that the Z-direction presents a vertical continuous passage through the entire polymer-based composite material.

[0051] The technical solutions in the present application will be described clearly and completely in combination with the embodiments in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0052] Embodiment 1

[0053] The Z-direction fibers are prepared by the following steps:

[0054] A 15wt% polyacrylonitrile solution is prepared by using dimethyl sulfoxide as a solvent, the polyacrylonitrile solution is coated on the surface of mesophase pitch-based carbon fibers (specifications: 3K, diameter: 9μm) by using an impregnation method, the solvent is volatilized by passing through a drying oven (temperature: 80°C), and a polyacrylonitrile layer (thickness: 0.2mm, as the Z-direction fibers) is formed on the surface of the mesophase pitch-based carbon fibers.

[0055] The three-dimensional fabric reinforcement is prepared by the following steps:

[0056] A high-strength polyacrylonitrile carbon fiber T300 (specification 6K, diameter 7 μm) is used as the X-direction fiber and the Y-direction fiber, the X-direction fiber and the Y-direction fiber are woven to form a cross-laminated layer, and the Z-direction fiber penetrates through the thickness direction of two layers of the cross-laminated layer to obtain a three-dimensional fabric reinforcement with a three-direction cross structure, wherein the thickness of a single layer of the cross-laminated layer is 2 mm, the interlayer spacing is 6 mm, the volume fraction of the Z-direction fiber in the three-dimensional fabric reinforcement is 15%, the volume fraction of the X-direction fiber is 42%, and the volume fraction of the Y-direction fiber is 43%.

[0057] A polymer matrix composite is prepared, comprising the following steps:

[0058] The epoxy resin E51 and the polyethylene glycol diglycidyl ether (PEGDGE) diluent are uniformly mixed at a molar ratio of 100:10, then 10% of the triethylenetetramine curing agent by mass of the epoxy resin E51 is added and stirred uniformly to obtain a resin matrix system;

[0059] The three-dimensional fabric reinforcement is laid in a mold, and the resin matrix system is injected into the mold at room temperature using an RTM process with an injection machine, wherein the volume ratio of the resin matrix system to the three-dimensional fabric reinforcement is 4:6, and the injection pressure is 0.6 MPa; after the injection is completed, the composite is placed in an oven for curing at 90°C for 3 h, and then curing at 120°C for 3.5 h; after demolding, the upper and lower surfaces of the composite are polished, and the specifications of the sandpaper used are 400 mesh, 800 mesh, 1000 mesh and 2000 mesh in sequence until the Z-direction fiber ends are directly exposed, the upper and lower surfaces of the composite are parallel and the thickness direction is perpendicular to the horizontal plane, and the Z-direction fiber is in a vertical and continuous state, so that the Z-direction presents a vertical and continuous path.

[0060] Example 2

[0061] The Z-direction fiber is prepared, comprising the following steps:

[0062] Polyvinyl alcohol particles are added to warm water at 25°C, and stirred at a speed of 200 r / min for 1.5 h, and the polyvinyl alcohol particles are fully water-swollen, the temperature is raised to 90°C, and the stirring is continued for 3 h; the temperature is cooled to room temperature, and ethanol is added and stirred for 1 h to obtain a polyvinyl alcohol solution (the mass fraction of polyvinyl alcohol is 5%, and the volume ratio of water to ethanol is 1:1); the polyvinyl alcohol solution is coated on the surface of mesophase pitch-based carbon fiber (specification 3K, diameter 9 μm) by the dipping method, and the solvent is volatilized by an oven (temperature 75°C) to form a polyvinyl alcohol layer (thickness 0.5 mm) on the surface of the mesophase pitch-based carbon fiber as the Z-direction fiber.

[0063] The three-dimensional fabric reinforcement is prepared, comprising the following steps:

[0064] The high-strength polyacrylonitrile carbon fiber T800 (specification 6K, diameter 5 μm) is used as the X-direction fiber and Y-direction fiber, the X-direction fiber and Y-direction fiber are woven to form orthogonal layers, and the Z-direction fiber penetrates through the thickness direction of the three layers of the orthogonal layers to obtain a three-dimensional fabric reinforcement with a three-direction orthogonal structure, wherein the thickness of a single layer of the orthogonal layer is 4 mm, the interlayer spacing is 8 mm, the volume fraction of the Z-direction fiber in the three-dimensional fabric reinforcement is 20%, the volume fraction of the X-direction fiber is 40%, and the volume fraction of the Y-direction fiber is 40%.

[0065] A polymer matrix composite is prepared, comprising the following steps:

[0066] The epoxy resin E51 and the polyethylene glycol diglycidyl ether (PEGDGE) diluent are mixed uniformly at a molar ratio of 100:10, then 60% of the phthalic anhydride curing agent by mass of the epoxy resin E51 is added and stirred uniformly to obtain a resin matrix system;

[0067] The three-dimensional fabric reinforcement is laid in a mold, and the resin matrix system is injected into the mold at room temperature using an RTM process, wherein the volume ratio of the resin matrix system to the three-dimensional fabric reinforcement is 4:6, and the injection pressure is 0.8 MPa; after injection, the composite material is placed in an oven for curing at 90°C for 3 h, and then cured at 120°C for 3.5 h; after demolding, the upper and lower surfaces of the composite material are polished using sandpaper with specifications of 400 mesh, 800 mesh, 1000 mesh and 2000 mesh in sequence until the Z-direction fiber ends are directly exposed, the upper and lower surfaces of the composite material are parallel and the thickness direction is perpendicular to the horizontal plane, and the Z-direction fiber is in a vertical and continuous state, so that the Z-direction presents a vertical and continuous path.

[0068] Example 3

[0069] The X-direction fiber, Y-direction fiber and Z-direction fiber are prepared, comprising the following steps:

[0070] The polyphenylene sulfide resin and industrial alcohol are poured into a ball mill cylinder at a mass ratio of 1:4, and ball milling is performed until the particle size is less than 120 μm, the obtained suspension is loaded into a spray gun, and the surface of the mesophase pitch-based carbon fiber (specification 3K, diameter 9 μm) is sprayed, and then dried through a drying oven (temperature 75°C) to volatilize the solvent; the above spraying-drying operation is repeated to form a polyphenylene sulfide resin layer (thickness of each spraying about 0.05 mm, total thickness 0.4 mm, as the Z-direction fiber) on the surface of the mesophase pitch-based carbon fiber;

[0071] A polyphenylene sulfide resin layer (thickness of each spray: about 0.05 mm, total thickness: 0.4 mm, as the X-directional fibers and the Y-directional fibers) was formed on the surface of high model polyacrylonitrile carbon fiber M55J (specification: 6K, diameter: 5 μm) according to the above method.

[0072] A three-dimensional fabric reinforcement was prepared by the following steps:

[0073] The X-directional fibers and the Y-directional fibers were woven to form orthogonal plies, and the Z-directional fibers were arranged to pass through the thickness direction of the two layers of the orthogonal plies, thereby obtaining a three-dimensional fabric reinforcement having a three-directional orthogonal structure, wherein the thickness of a single layer of the orthogonal plies was 4 mm, the interlayer spacing was 8 mm, the volume fraction of the Z-directional fibers in the three-dimensional fabric reinforcement was 15%, the volume fraction of the X-directional fibers was 43%, and the volume fraction of the Y-directional fibers was 42%.

[0074] A polymer matrix composite material was prepared by the following steps:

[0075] The cyanate ester resin was heated and melted at 120°C, and then a catalyst triethylamine was added and stirred uniformly. The temperature was raised to 150°C, and the reaction was carried out for 2 h. Then the temperature was lowered to 115°C, and a diluent dibutyl phthalate was added and stirred uniformly, and the reaction was carried out for 30 min, thereby obtaining a resin matrix system; wherein the mass ratio of the cyanate ester resin, the diluent and the catalyst was 20:5:1.

[0076] The three-dimensional fabric reinforcement was placed in a mold, and the resin matrix system was injected into the mold at room temperature by using an injection machine by an RTM process, wherein the volume ratio of the resin matrix system to the three-dimensional fabric reinforcement was 4:6, and the injection pressure was 1 MPa. After the injection was completed, the three-dimensional fabric reinforcement was placed in an oven and cured at 150°C for 4 h, and then successively cured at 180°C for 2 h, at 200°C for 2 h, at 220°C for 2 h and at 240°C for 4 h. After demolding, the upper and lower surfaces of the composite material were polished by using sandpaper with specifications of 400 mesh, 800 mesh, 1000 mesh and 2000 mesh in sequence until the end portions of the Z-directional fibers were directly exposed, the upper and lower surfaces of the composite material were parallel and the thickness direction was perpendicular to the horizontal plane, and the Z-directional fibers were kept in a vertical and continuous state as a whole, so that the Z-directional fibers presented a vertical and continuous path.

[0077] Comparative Example 1

[0078] A laminated composite material was prepared by the following steps:

[0079] The X-directional fibers and the Y-directional fibers were prepared according to the method of Example 1, and the X-directional fibers and the Y-directional fibers were woven to form orthogonal plies.

[0080] The resin matrix system was prepared according to the method of Example 1.

[0081] The orthogonal plies are laid up in a mold, two layers are laid up, and then a laminate composite is prepared by using the orthogonal plies as a preform according to the method of Example 1.

[0082] Test Example

[0083] The properties of the composite materials prepared in Examples 1-3 and Comparative Example 1 are tested as follows:

[0084] (1) The thermal conductivity of the composite material in the Z direction is calculated according to the formula λ = α · C p · ρ, wherein

[0085] λ - the thermal conductivity of the composite material in the Z direction, W / (m·K);

[0086] α - the thermal diffusivity of the composite material in the Z direction, mm 2 / s;

[0087] C p - the specific heat capacity of the composite material, J / (g·K);

[0088] ρ - the bulk density of the composite material, g / cm 3 .

[0089] Wherein, α: obtained by laser flash method (specifically, tested according to the standard method of GB / T 22588-2008);

[0090] C p : using the DSC function in STA, the specific heat capacity of the sample to be tested is calculated by comparing the measurement results of the standard sample with known specific heat and the sample to be tested with unknown specific heat according to the standard method of ASTM E1269;

[0091] ρ: using distilled water as the solvent, the bulk density of the composite material cut into a fixed size after centrifugation is tested by the drainage method, which can be calculated by the formula ρ = m0· ρ 水 / (m0-m1), wherein m0 is the mass of the laminate in air, and m1 is the mass corresponding to the balance after the laminate is completely immersed.

[0092] (2) The electrical conductivity of the composite material in the Z direction is measured using a double electrical measurement four-probe tester (Guangzhou Four-probe Co., Ltd., RTS-9).

[0093] (3) The interlaminar shear strength performance of the composite material is tested according to the standard of ASTM D2344-06 using an INSTRON3382 electronic universal testing machine, and the test speed is constant at 1 mm / min. The interlaminar shear strength of the composite material is calculated by the formula τ = 3· F / (4· b· h), wherein

[0094] τ - interlaminar shear strength of the composite material, MPa;

[0095] F - the maximum load appeared in the test, N;

[0096] b - the width of the sample, mm;

[0097] h - the thickness of the sample, mm.

[0098] 5 effective data are taken from each group of samples, and the average value is calculated as the interlaminar shear strength of the composite material.

[0099] Table 1: performance test results of the composite materials prepared in Examples 1-3 and Comparative Example 1

[0100]

[0101] As shown in Table 1, after weaving high model carbon fibers (specifically mesophase pitch-based fibers) in the Z direction, the obtained three-dimensional fabric reinforcement is used as a preform to prepare a composite material, compared with a laminated composite material, the thermal conductivity, electrical conductivity and interlaminar shear strength of the composite material in the Z direction are greatly improved.

[0102] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A polymer-based composite material, characterized in that, The preparation method includes the following steps: The preparation of Z-axis fibers includes the following steps: Polyvinyl alcohol (PVA) particles were added to warm water at 25°C and stirred at 200 r / min for 1.5 h until the PVA particles fully absorbed water and swelled. The temperature was then raised to 90°C and stirred continuously for 3 h. After cooling to room temperature, ethanol was added and stirring was continued for 1 h to obtain a PVA solution. The mass fraction of PVA in the PVA solution was 5%, and the volume ratio of water to ethanol was 1:

1. The PVA solution was then coated onto the surface of mesophase pitch-based carbon fibers with a specification of 3K and a diameter of 9 μm using an impregnation method. The solvent was evaporated by drying in an oven at 75°C, forming a PVA layer with a thickness of 0.5 mm on the surface of the mesophase pitch-based carbon fibers, thus obtaining Z-axis fibers. The preparation of three-dimensional fabric reinforcements includes the following steps: High-strength polyacrylonitrile carbon fiber T800 with a specification of 6K and a diameter of 5μm is used as the X-axis fiber and Y-axis fiber. The X-axis fiber and Y-axis fiber are woven into an orthogonal layup. At the same time, the Z-axis fiber runs through the thickness direction of the three orthogonal layup layers to obtain a three-dimensional fabric reinforcement with a three-dimensional orthogonal structure. The thickness of a single orthogonal layup layer is 4mm, the interlayer spacing is 8mm, and the volume fraction of Z-axis fiber in the three-dimensional fabric reinforcement is 20%, the volume fraction of X-axis fiber is 40%, and the volume fraction of Y-axis fiber is 40%. The preparation of polymer-based composite materials includes the following steps: The epoxy resin E51 and polyethylene glycol diglycidyl ether diluent are mixed evenly at a molar ratio of 100:

10. Then, 60% of the mass of epoxy resin E51 as phthalic anhydride curing agent is added and stirred evenly to obtain the resin matrix system. The three-dimensional fabric reinforcement was laid in a mold, and the resin matrix system was injected using an injection molding machine at room temperature using the RTM process. The volume ratio of the resin matrix system to the three-dimensional fabric reinforcement was 4:6, and the injection pressure was 0.8 MPa. After injection, it was placed in an oven and cured at 90°C for 3 hours, and then cured at 120°C for 3.5 hours. After demolding, the composite material was obtained. The upper and lower surfaces of the composite material were then sanded with sandpaper of 400 grit, 800 grit, 1000 grit, and 2000 grit, respectively, until the Z-direction fiber ends were directly exposed. The upper and lower surfaces of the composite material were parallel, and the thickness direction was perpendicular to the horizontal plane. The Z-direction fibers maintained a vertically continuous state, so that the Z-direction presented a vertically continuous path, thus obtaining the polymer-based composite material.

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