Asphalt carbon fiber reinforced resin-based composite material and preparation method thereof

Abstract

The invention relates to a pitch carbon fiber reinforced resin-based composite material and a preparation method thereof. Pitch carbon fibers are subjected to electrochemical surface treatment in an acidic electrolyte and then treated with a silane coupling agent; blending and dispersing a polyfunctional epoxy resin matrix, inorganic nano heat-conducting particles treated by a silane coupling agent, a high-temperature curing agent and an organic solvent to obtain an epoxy resin matrix solution; winding the pitch carbon fiber and the epoxy resin matrix solution to prepare a prepreg, drying, cutting, paving, and hot-pressing and curing to obtain the high-compression high-thermal-conductivity pitch carbon fiber reinforced resin matrix composite material. The composite material has the unidirectional compression strength of 305-420MPa and the unidirectional thermal conductivity of 295-618W / (m.K), has excellent compression performance and thermal conductivity, can be used for preparing aerospace craft structures / functional parts, and can also meet the requirements of other industrial equipment fields on light-weight, high-strength, high-modulus and high-thermal-conductivity composite materials.

Description

Technical Field

[0001] The present invention belongs to the field of resin-based composite materials, and specifically relates to a method for preparing a high-compression and high-thermal-conductivity asphalt carbon fiber reinforced resin-based composite material and the composite material. Background Art

[0002] High thermal conductivity asphalt-based carbon fiber is a high-performance inorganic fiber made from optically anisotropic mesophase asphalt through melt spinning, oxidative carbonization and graphitization. High thermal conductivity asphalt carbon fiber has higher thermal conductivity and tensile modulus and lower thermal expansion coefficient than polyacrylonitrile-based carbon fiber. Its reinforced resin-based composite material plays an irreplaceable role in high thermal conductivity structural panels, high rigidity structural parts, zero expansion coefficient parts in temperature alternating environments, etc. It is the core material in the main structure of spacecraft and the electronic industry.

[0003] According to literature reports, the compression strength and interlaminar shear strength of the resin-based composite materials prepared by Japan Graphite Company using high thermal conductivity asphalt carbon fiber XN-90 and YS-90A with a thermal conductivity of 500W / (m·K) and medium-temperature cured epoxy resin are 360MPa and 60MPa respectively, and its compression performance is much lower than that of the MJ series polyacrylonitrile-based high-strength and high-modulus carbon fiber composite materials of Japan Toray Company. This is because the high thermal conductivity asphalt carbon fiber has been graphitized at nearly 3000℃, the internal graphite structure is well developed, and the orientation degree along the fiber direction is high, resulting in poor longitudinal compression performance, which seriously limits the application of high thermal conductivity asphalt carbon fiber composites in structural materials. At the same time, due to its extremely high tensile modulus and great brittleness, it is very easy to break and damage during the preparation of resin-based composite materials. In addition, its surface inertia is extremely high, and it is difficult to form a good interface with the resin matrix, resulting in low utilization of fiber thermal conductivity and mechanical properties, and the mechanical properties and thermal conductivity of the prepared composite material are difficult to meet expectations.

[0004] As the high thermal conductivity asphalt carbon fiber technology continues to improve thermal conductivity, the internal structure of carbon fiber has a higher degree of orientation, greater surface inertness, and worse bonding with resin. The mechanical properties of the prepared composite materials, especially the compressive strength, are far lower than the structural design requirements, making it difficult to meet the comprehensive performance requirements of aerospace products for lightweight, high-strength, and high-thermal conductivity composite materials. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a high thermal conductivity asphalt carbon fiber reinforced resin-based composite material with high compressive strength and the composite material. The preparation method solves the problem that carbon fiber is prone to instability and damage under compressive load, and improves the compression performance of carbon fiber composite materials. The asphalt carbon fiber reinforced resin-based composite material of the present invention can be used to prepare aerospace vehicle structural and functional integrated components, and can also meet the needs of other industrial equipment fields for lightweight, high-compression and high-thermal conductivity composite materials.

[0006] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0007] The preparation method of the pitch carbon fiber reinforced resin-based composite material comprises the following steps:

[0008] (1) electrochemically treating the pitch carbon fiber in an acidic electrolyte, and then washing and drying the carbon fiber, wherein the acidic electrolyte is at least one of a mixture of phosphoric acid and calcium phosphate and a mixture of nitric acid and calcium nitrate;

[0009] (2) immersing the asphalt carbon fiber obtained in step (1) in a silane coupling agent solution and then taking it out and drying it;

[0010] (3) blending and dispersing the multifunctional epoxy resin matrix, the inorganic nano-thermal conductive particles treated with a silane coupling agent, a curing agent, and an organic solvent to obtain an epoxy resin matrix solution;

[0011] (4) The asphalt carbon fiber obtained in step (2) and the epoxy resin matrix solution obtained in step (3) are wound to form a prepreg, which is then cut and laid into layers after drying, and finally hot-pressed and cured to obtain an asphalt carbon fiber reinforced resin-based composite material.

[0012] The carbon content of the pitch carbon fiber in step (1) is ≥99%, the tensile strength is ≥2500MPa, the tensile modulus is ≥700GPa, and the thermal conductivity is ≥500W / (m·K).

[0013] The concentration of the acidic electrolyte in step (1) is 0.1 to 10 mol / dm 3 , the mass ratio of acid to calcium salt is 1:0.1~0.3, the electrolysis voltage is 0.5~10V, the current is 0.1~1mA, and the electrolysis time is 0.5~10min.

[0014] The silane coupling agent in steps (2) and (3) is KH550 or KH560, and the solution concentration is 0.1-2wt%.

[0015] The multifunctional epoxy resin matrix in step (3) is at least one of 4,4'-diaminodiphenylmethane tetraglycidyl epoxy resin or 3,4-epoxycyclohexyl 3',4'-epoxycyclohexyl methyl ester.

[0016] The inorganic nano thermally conductive particles in step (3) are carbon nanotubes or graphene.

[0017] The curing agent in step (3) is at least one of hexahydrophthalic anhydride and methyl hexahydrophthalic anhydride.

[0018] The organic solvent in step (3) is at least one of acetone and tetrahydrofuran.

[0019] In step (3), the mass ratio of the multifunctional epoxy resin matrix, the inorganic nano-thermal conductive particles, the curing agent, and the organic solvent is 100:0.1-2:30-80:30-60.

[0020] The hot pressing curing temperature in step (4) is 80-180° C., the pressure is 0.1-0.4 MPa, and the curing time is 2-12 hours.

[0021] Compared with the prior art, the embodiments of the present invention have at least the following beneficial effects:

[0022] (1) The present invention uses acidic electrolyte electrochemical treatment and silane coupling agent treatment of high thermal conductivity asphalt carbon fiber as a composite reinforcement, which significantly increases the surface area and oxygen-containing functional groups of the carbon fiber, increases the interfacial bonding strength and interlaminar shear performance between the carbon fiber and the resin matrix, and solves the problem that the high thermal conductivity asphalt carbon fiber has high surface inertia and weak bonding with the resin matrix, which leads to the easy instability and damage of the carbon fiber under compression load, and significantly improves the compression performance of the high thermal conductivity asphalt carbon fiber composite material.

[0023] (2) The present invention preferably uses a highly active multifunctional epoxy resin and a high-temperature curing agent system, which further ensures the improvement of the stiffness of the resin matrix and the good bonding with the surface of the highly inert carbon fiber. At the same time, the inorganic nano-thermal conductive particles are treated with a silane coupling agent and uniformly dispersed in the organic resin matrix, thereby improving the thermal conductivity of the matrix resin and the thermal conductivity path with the fiber, and constructing a multi-scale thermal conductive network, which is beneficial to fully exert the mechanical and thermal conductivity properties of the composite material.

[0024] (3) The high-compression and high-thermal conductivity asphalt carbon fiber reinforced epoxy resin composite material prepared by the present invention has high compressive mechanical properties and good thermal conductivity, and is suitable for aerospace aircraft components with integrated thermal conductivity functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a process flow chart for preparing the asphalt carbon fiber reinforced resin-based composite material of the present invention;

[0026] Figure 2 This is a microscopic photograph of the surface of asphalt carbon fiber treated with acidic electrolyte in Example 1 of the present invention;

[0027] Figure 3 This is a microscopic photograph of the compressed cross-section of the asphalt carbon fiber reinforced resin-based composite material in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0029] like Figure 1The figure shows a process flow chart of the preparation of the asphalt carbon fiber reinforced resin-based composite material of the present invention. The preparation method of the asphalt carbon fiber reinforced resin-based composite material comprises the following steps:

[0030] (1) electrochemically treating the pitch carbon fiber in an acidic electrolyte, and then washing and drying the carbon fiber, wherein the acidic electrolyte is at least one of a mixture of phosphoric acid and calcium phosphate and a mixture of nitric acid and calcium nitrate;

[0031] (2) immersing the pitch carbon fiber obtained in step (1) in a silane coupling agent solution and then taking it out and drying it;

[0032] (3) blending and dispersing the multifunctional epoxy resin matrix, the inorganic nano-thermal conductive particles treated with a silane coupling agent, a curing agent, and an organic solvent to obtain an epoxy resin matrix solution;

[0033] (4) The asphalt carbon fiber obtained in step (2) and the epoxy resin matrix solution obtained in step (3) are wound to form a prepreg, which is then cut and laid into layers after drying, and finally hot-pressed and cured to obtain an asphalt carbon fiber reinforced resin-based composite material.

[0034] The carbon content of the pitch carbon fiber in step (1) is ≥99%, the tensile strength is ≥2500MPa, the tensile modulus is ≥700GPa, and the thermal conductivity is ≥500W / (m·K).

[0035] In step (1), the concentration of the acidic electrolyte is 0.1-10 mol / dm3, the mass ratio of acid to calcium salt is 1:0.1-0.3, the electrolysis voltage is 0.5-10 V, the current is 0.1-1 mA, and the electrolysis time is 0.5-10 min.

[0036] The silane coupling agent in steps (2) and (3) is KH550 or KH560, and the solution concentration is 0.1-2wt%.

[0037] The multifunctional epoxy resin matrix in step (3) is at least one of 4,4'-diaminodiphenylmethane tetraglycidyl epoxy resin or 3,4-epoxycyclohexyl 3',4'-epoxycyclohexyl methyl ester.

[0038] The inorganic nano thermally conductive particles in step (3) are carbon nanotubes or graphene.

[0039] The curing agent in step (3) is at least one of hexahydrophthalic anhydride and methyl hexahydrophthalic anhydride.

[0040] The organic solvent in step (3) is at least one of acetone and tetrahydrofuran.

[0041] In step (3), the mass ratio of the multifunctional epoxy resin matrix, the inorganic nano-thermal conductive particles, the curing agent, and the organic solvent is 100:0.1-2:30-80:30-60.

[0042] The hot pressing curing temperature in step (4) is 80-180° C., the pressure is 0.1-0.4 MPa, and the curing time is 2-12 hours.

[0043] The compression performance and interlaminar performance of the unidirectional composite material are tested according to the provisions of ASTM D-695 and ASTM D-2344, respectively, and the thermal conductivity is tested according to the provisions of ASTM E-1461. The volume fraction of carbon fiber in the composite material is 60%.

[0044] Example 1

[0045] (1) Place XN-90 high thermal conductivity asphalt carbon fiber with a thermal conductivity of 500 W / (m·K) in a mixed electrolyte of phosphoric acid and calcium phosphate with a weight ratio of 1:0.3 for electrochemical surface treatment for 1 min, with an electrolysis voltage of 5 V and a current of 0.2 mA, and then wash and dry with pure water;

[0046] (2) The high thermal conductivity asphalt carbon fiber obtained in step (1) is immersed in a 2 wt % aqueous solution of KH550 silane coupling agent for 30 min, then taken out and dried to obtain a high activity and high thermal conductivity carbon fiber;

[0047] (3) Blending and dispersing 100 parts of 4,4'-diaminodiphenylmethane tetraglycidyl epoxy resin, 2 parts of carbon nanotubes treated with KH550, 50 parts of hexahydrophthalic anhydride, and 50 parts of acetone to obtain an epoxy resin matrix solution;

[0048] (4) The high-activity and high-thermal-conductivity carbon fiber of step (2) and the epoxy resin matrix solution of step (3) are used to wind and arrange yarns to prepare prepreg, cut and lay layers after drying, and then hot-press and cure, and the curing process is (80℃ / 2h / 0.2MPa)+(130℃ / 2h / 0.2MPa)+(180℃ / 2h / 0.4MPa), and the high-compression and high-thermal-conductivity asphalt carbon fiber reinforced resin matrix composite material is prepared by cooling and demolding. The properties of the composite material are shown in Table 1.

[0049] Figure 2 The figure shows the surface morphology of the asphalt carbon fiber after surface treatment with an acidic electrolyte in Example 1 of the present invention. Protrusions are formed on the surface of the high thermal conductivity asphalt carbon fiber electrochemically treated by the present invention, which significantly increases the specific surface area of ​​the carbon fiber and improves the content of oxygen-containing groups on the surface. Figure 3This is a microscopic photograph of the compressed cross-section of the asphalt carbon fiber reinforced resin-based composite material in Example 1 of the present invention. After treatment with a silane coupling agent, the surface activity of the high thermal conductivity asphalt carbon fiber and the interfacial bonding strength with the organic resin matrix are improved, thereby improving the compression performance of the composite material.

[0050] Example 2

[0051] (1) Place TYG-1 high thermal conductivity asphalt carbon fiber with a thermal conductivity of 600W / (m·K) in a mixed electrolyte of phosphoric acid and calcium phosphate with a weight ratio of 1:0.3 for electrochemical surface treatment for 2 minutes, with an electrolysis voltage of 3V and a current of 0.5mA, and then wash and dry with pure water;

[0052] (2) The high thermal conductivity asphalt carbon fiber obtained in step (1) is immersed in a 2 wt % aqueous solution of KH550 silane coupling agent for 10 min, then taken out and dried to obtain a high activity and high thermal conductivity carbon fiber;

[0053] (3) Blending and dispersing 100 parts of 4,4'-diaminodiphenylmethane tetraglycidyl epoxy resin, 2 parts of carbon nanotubes treated with KH550, 50 parts of hexahydrophthalic anhydride, and 50 parts of acetone to obtain an epoxy resin matrix solution;

[0054] (4) The high-activity and high-thermal-conductivity carbon fiber of step (2) and the epoxy resin matrix solution of step (3) are used to wind and arrange yarns to prepare prepreg, cut and lay layers after drying, and then hot-press and cure, the curing process is (80°C / 2h / 0.2MPa)+(130°C / 2h / 0.2MPa)+(180°C / 2h / 0.4MPa), and the high-compression and high-thermal-conductivity asphalt carbon fiber reinforced resin matrix composite material is prepared by cooling and demolding. The properties of the composite material are shown in Table 1.

[0055] Example 3

[0056] (1) The K13D2U high thermal conductivity asphalt carbon fiber with a thermal conductivity of 800 W / (m·K) was placed in a mixed electrolyte of nitric acid and calcium nitrate with a weight ratio of 1:0.1 for electrochemical surface treatment for 1 min, with an electrolysis voltage of 10 V and a current of 0.2 mA, and then washed and dried with pure water;

[0057] (2) The high thermal conductivity asphalt carbon fiber obtained in step (1) is immersed in a 1 wt% aqueous solution of KH560 silane coupling agent for 5 minutes, then taken out and dried to obtain a high activity and high thermal conductivity carbon fiber;

[0058] (3) 100 parts of 3,4-epoxycyclohexyl 3',4'-epoxycyclohexyl methyl ester, 1 part of graphene treated with KH550, 60 parts of methylhexahydrophthalic anhydride, and 60 parts of tetrahydrofuran were mixed and dispersed to obtain an epoxy resin matrix solution;

[0059] (4) The high-activity and high-thermal-conductivity carbon fiber of step (2) and the epoxy resin matrix solution of step (3) are used to wind and arrange yarns to prepare prepreg, cut and lay layers after drying, and then hot-press and cure, the curing process is (120°C / 2h / 0.2MPa)+(180°C / 4h / 0.4MPa), and the high-compression and high-thermal-conductivity asphalt carbon fiber reinforced resin matrix composite material is prepared by cooling and demolding. The properties of the composite material are shown in Table 1.

[0060] Example 4

[0061] (1) Place K1100 high thermal conductivity asphalt carbon fiber with a thermal conductivity of 1100 W / (m·K) in a mixed electrolyte of nitric acid and calcium nitrate with a weight ratio of 1:0.1 for electrochemical surface treatment for 1 min, with an electrolysis voltage of 10 V and a current of 0.2 mA, and then wash and dry with pure water;

[0062] (2) The high thermal conductivity asphalt carbon fiber obtained in step (1) is immersed in a 1 wt% aqueous solution of KH560 silane coupling agent for 5 minutes, then taken out and dried to obtain a high activity and high thermal conductivity carbon fiber;

[0063] (3) 100 parts of 3,4-epoxycyclohexyl 3',4'-epoxycyclohexyl methyl ester, 1 part of graphene treated with KH550, 60 parts of methylhexahydrophthalic anhydride, and 60 parts of tetrahydrofuran were mixed and dispersed to obtain an epoxy resin matrix solution;

[0064] (4) The high-activity and high-thermal-conductivity carbon fiber of step (2) and the epoxy resin matrix solution of step (3) are used to wind yarns to prepare prepreg, cut and lay layers after drying, and then hot-pressed and cured. The curing process is (120°C / 2h / 0.2MPa)+(180°C / 4h / 0.4MPa), and the high-compression and high-thermal-conductivity asphalt carbon fiber reinforced resin matrix composite material is prepared by cooling and demolding. The properties of the composite material are shown in Table 1.

[0065] Comparative Example 1

[0066] Reported values ​​of mechanical properties of unidirectional composites made from Nippon Graphite's XN-90 high thermal conductivity asphalt carbon fibers and medium temperature cured epoxy resin.

[0067] Table 1 Properties of unidirectional high compression and high thermal conductivity asphalt carbon fiber reinforced resin composites

[0068]

[0069] It can be seen from Examples 1 to 4 that the unidirectional high-compression high-thermal conductivity asphalt carbon fiber reinforced resin composite material prepared by the present invention has a compression strength of 305 to 420 MPa, an interlaminar shear strength of 53 to 68 MPa, and a room temperature thermal conductivity of 295 to 618 W / (m·K). The prepared high-compression high-thermal conductivity asphalt carbon fiber reinforced resin composite material has excellent compression resistance and thermal conductivity, and can be used in advanced equipment structures / functional components such as aerospace vehicles, which fully illustrates the effect of the present invention.

[0070] The above description is only the best specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0071] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A method for preparing a pitch carbon fiber reinforced resin-based composite material, characterized in that: The following steps are involved: (1) electrochemically treating the pitch carbon fiber in an acidic electrolyte, and then washing and drying the carbon fiber, wherein the acidic electrolyte is at least one of a mixture of phosphoric acid and calcium phosphate and a mixture of nitric acid and calcium nitrate; (2) dipping the asphalt carbon fiber obtained in step (1) in a silane coupling agent solution and then taking it out and drying it; (3) blending and dispersing the multifunctional epoxy resin matrix, the inorganic nano-thermal conductive particles treated with a silane coupling agent, a curing agent, and an organic solvent to obtain an epoxy resin matrix solution; (4) Prepreg is prepared from the asphalt carbon fiber obtained in step (2) and the epoxy resin matrix solution obtained in step (3), which is cut and laid into layers after drying, and finally hot-pressed and cured to obtain an asphalt carbon fiber reinforced resin-based composite material.

2. The method for preparing a pitch carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The carbon content of the pitch carbon fiber in step (1) is ≥99%, the tensile strength is ≥2500MPa, the tensile modulus is ≥700GPa, and the thermal conductivity is ≥500W / (m·K).

3. The method for preparing a pitch carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The concentration of the acidic electrolyte in step (1) is 0.1 to 10 mol / dm 3 , the mass ratio of acid to calcium salt is 1:0.1~0.3, the electrolysis voltage is 0.5~10V, the current is 0.1~1mA, and the electrolysis time is 0.5~10min.

4. The method for preparing a pitch carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The silane coupling agent in steps (2) and (3) is KH550 or KH560, and the solution concentration is 0.1-2wt%.

5. The method for preparing a pitch carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The multifunctional epoxy resin matrix in step (3) is at least one of 4,4'-diaminodiphenylmethane tetraglycidyl epoxy resin or 3,4-epoxycyclohexyl 3',4'-epoxycyclohexyl methyl ester.

6. The method for preparing a pitch carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The inorganic nano thermally conductive particles in step (3) are carbon nanotubes or graphene.

7. The method for preparing a pitch carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The curing agent in step (3) is at least one of hexahydrophthalic anhydride and methyl hexahydrophthalic anhydride.

8. The method for preparing a pitch carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The organic solvent in step (3) is at least one of acetone and tetrahydrofuran.

9. The method for preparing a pitch carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: In step (3), the mass ratio of the multifunctional epoxy resin matrix, the inorganic nano-thermal conductive particles, the curing agent, and the organic solvent is 100:0.1-2:30-80:30-60.

10. The method for preparing the pitch carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The hot pressing curing temperature in step (4) is 80-180° C., the pressure is 0.1-0.4 MPa, and the curing time is 2-12 hours.

11. A pitch carbon fiber reinforced resin matrix composite material, characterized in that: The method according to any one of claims 1 to 10 is used to prepare the compound.

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