A method for modifying carbon fiber with multidimensional nanoparticles and its application in CF / PEEK composite materials

Abstract

A method for modifying carbon fibers with multidimensional nanoparticles and its application in CF / PEEK composite materials. The present invention belongs to the field of carbon fiber modification and CF / PEEK composite material preparation. The purpose of the present invention is to solve the interface problem of CF / PEEK composite materials and improve the overall mechanical properties of the composite materials. The method of the present invention comprises the following steps: first, activating the desized CF fabric and then modifying it with PEI; then immersing it in a MXene suspension; and then immersing it in a dispersion of PEI-modified CB to obtain carbon fibers modified with multidimensional nanoparticles. The CF / PEEK composite material of the present invention can achieve a bending strength of 781.54 MPa and an interlaminar shear strength of 67.1 MPa. At the same time, its electromagnetic shielding performance in the X-band reaches 29.28 dB, and it has excellent comprehensive performance.

Description

Technical Field

[0001] The invention belongs to the field of carbon fiber modification and CF / PEEK composite material preparation, and particularly relates to a method for modifying carbon fibers with multidimensional nanoparticles and an application of the method in CF / PEEK composite materials. Background Art

[0002] Carbon fiber reinforced polymer-based composites possess excellent physical and chemical properties, including high specific strength and stiffness, lightweight, strong corrosion resistance, excellent thermal stability, and ease of molding. They are widely used in a wide range of fields, including aerospace, defense, military, and transportation. Among commonly used high-performance thermoplastic resin matrices, polyetheretherketone (PEEK) boasts the best overall performance. It is a semi-crystalline polymer with a structure that contains benzene rings, ether bonds, and ketone bonds.

[0003] However, the surface of carbon fiber (CF) is smooth, chemically inert and has low surface energy. The inertness of PEEK causes the interfacial bonding between the fiber and the matrix to be weak, which affects the overall performance of the CF / PEEK composite material. Therefore, it is necessary to modify the surface of the carbon fiber. In recent years, many carbon fiber surface modification methods have been developed, mainly by improving the polarity, surface roughness and surface energy of the fiber to enhance the interfacial properties of carbon fiber composites. However, most modification methods, while improving the interfacial properties, have the disadvantages of damaging the strength of the fiber itself, consuming time, and using toxic solvents. Therefore, studying a simple and environmentally friendly CF surface modification method is crucial to solving the interface problems of CF / PEEK composites, improving the overall mechanical properties of the composite material and fully exerting its functionality. Summary of the Invention

[0004] The purpose of the present invention is to solve the interface problem of CF / PEEK composite materials and improve the overall mechanical properties of the composite materials, and to provide a method for modifying carbon fibers with multidimensional nanoparticles and its application in CF / PEEK composite materials.

[0005] One of the objects of the present invention is to provide a method for modifying carbon fibers with multidimensional nanoparticles, the method being carried out by the following steps:

[0006] S1: Activating the surface oxygen-containing functional groups of the desized CF fabric, and then immersing it in an aqueous solution of polyethyleneimine (PEI) under heating conditions to obtain PEI-modified CF;

[0007] S2: immerse the PEI-modified CF in a MXene suspension and dry it at room temperature to obtain a MXene-modified CF, which is recorded as MCF.

[0008] S3: Conductive carbon black (CB) and PEI were added to deionized water, magnetically stirred under heating conditions, and then ultrasonically treated, filtered, washed, low-temperature dried, and ground to obtain PEI-modified CB;

[0009] S4: Dispersing the PEI-modified CB in deionized water to obtain a dispersion, then immersing the MCF in the dispersion, and drying at a low temperature to obtain a carbon fiber modified with multidimensional nanoparticles.

[0010] It is further defined that the desizing process of the CF fabric in S1 is: Soxhlet extraction in acetone under heating conditions, followed by washing and drying.

[0011] It is further defined that in S1, the surface oxygen-containing functional groups are activated by soaking in Michaelis acid / ethanol solution.

[0012] It is further defined that the concentration of the PEI aqueous solution in S1 is 0.5-1.5 g / L.

[0013] It is further defined that the soaking temperature in S1 is 40-60° C. and the soaking time is 0.5-1.5 h.

[0014] It is further defined that the concentration of MXene suspension in S2 is 0.5-1.5 g / L.

[0015] Further defined, soaking in S2 for 20-40 minutes.

[0016] It is further defined that the mass ratio of CB to PEI in S3 is (0.5-1.5):1.

[0017] It is further defined that the ratio of PEI to deionized water in S3 is 1 g: (80-120) mL.

[0018] It is further defined that the magnetic stirring temperature in S3 is 50-70° C. and the time is 3-5 h.

[0019] Further defined, the ultrasonic treatment in S3 is 3-5 h.

[0020] It is further defined that the low temperature drying temperature in S3 is 25-40°C.

[0021] It is further defined that the concentration of the dispersion in S4 is 1-5 g / L.

[0022] Further defined, soaking in S4 for 20-40 minutes.

[0023] It is further defined that the low temperature drying temperature in S4 is 25-40°C.

[0024] A second object of the present invention is to provide a multi-dimensional nanoparticle modified carbon fiber prepared according to the above method.

[0025] A third object of the present invention is to provide a CF / PEEK composite material based on the above-mentioned multidimensional nanoparticle-modified carbon fiber.

[0026] A fourth object of the present invention is to provide a method for preparing a CF / PEEK composite material based on the multidimensional nanoparticle-modified carbon fiber, the method being carried out according to the following steps:

[0027] It is made by alternately laminating multi-dimensional nanoparticle modified carbon fibers and PEEK films and then hot pressing them.

[0028] It is further defined that the volume ratio of the multi-dimensional nanoparticle modified carbon fiber and the PEEK film is (7-5):4.

[0029] The hot pressing conditions are further defined as follows: preheating at 150-250°C for 20-40 minutes under 4-6 MPa, heating to 350-400°C and keeping warm for 20-40 minutes, cooling to 250-350°C and keeping warm for 20-40 minutes, and cooling to room temperature.

[0030] A fifth object of the present invention is to provide an application of the above-mentioned CF / PEEK composite material in the field of electromagnetic shielding.

[0031] Compared with the prior art, the present invention has the following significant effects:

[0032] (1) In order to solve the interface problem between CF and PEEK, the present invention proposes a simple and environmentally friendly method for electrostatic assembly of fiber surface. First, cationic polyelectrolytes with rich amino groups are used to electrostatically interact with oxygen functional groups on ACFs. The surface of CF carries cationic charges. Due to the branched molecular structure of polyelectrolyte PEI, it can decompose NH3 in water. + 、NRH2 + and NR2H + Cationic groups such as PEI and MXene can be adsorbed on the CF surface under electrostatic interaction to make the fiber positively charged. Therefore, PEI can act as a bridging part to connect the ACF with the self-assembled stacking layer. Then, MXene nanosheets with positive and negative charge properties and modified PEI-CB nanoparticles are deposited on the fiber surface in sequence, avoiding the use of organic solvents and the problem of damaging the strength of the body. At the same time, the activity of the fiber surface and the physical interlocking effect between it and the resin are enhanced to improve the interface bonding between the fiber and the matrix, thereby improving its mechanical properties and electromagnetic shielding performance, and preparing a composite material with integrated structure and function.

[0033] (2) The present invention proposes a simple and feasible green assembly method to deposit nanomaterials of different dimensions on the CF surface, which effectively improves the bonding strength between carbon fiber and polyetheretherketone. The bending strength of the modified composite material can reach 781.54MPa, and the interlaminar shear strength is 67.1MPa. At the same time, the electromagnetic shielding performance in the X-band reaches 29.28dB, with excellent comprehensive performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The morphology SEM images of MXene, CB, and PEI-CB used in the examples of the present invention; wherein (a, b) represent MXene, (c, d) represent CB, and (e, f) represent PEI-CB;

[0035] Figure 2 The Raman spectra of the raw materials used in the examples of the present invention and the products obtained in each step are shown in FIG.

[0036] Figure 3 These are SEM images of the morphology of the carbon fibers modified with MXene / PEI-CB in the examples of the present invention and the unmodified carbon fibers in the comparative examples; a) represents the comparative example, and b) represents the examples;

[0037] Figure 4 A comparison chart of the flexural strength and interlaminar shear test of carbon fiber reinforced polyetheretherketone composite materials prepared in the examples of the present invention and the comparative examples;

[0038] Figure 5 This is a comparison chart of the electromagnetic shielding performance of the carbon fiber reinforced polyetheretherketone composite materials prepared in the examples of the present invention and the comparative examples in the X-band. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods, and instruments used are conventional in the art and can be obtained commercially by those skilled in the art unless otherwise specified.

[0041] As used in the following examples, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0042] The term "one embodiment" or "embodiment" in the following embodiments refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0043] When amount, concentration or other value or parameter are represented with the range of scope, preferred range or a series of upper preferred value and lower preferred value limit, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, and no matter whether this scope is disclosed separately.For example, when disclosing scope "1 to 5", described scope should be interpreted as including scope "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc.When numerical range is described in this article, unless otherwise stated, otherwise this scope is intended to include its end value and all integers and fractions within the scope.In this application specification and claims, range limitation can be combined and / or interchanged, and if these ranges are not otherwise stated, include all subranges contained therein.

[0044] The indefinite articles "a" and "an" before the elements or components of the present invention do not limit the quantity requirement (i.e. the number of times they appear). Therefore, "a" or "an" should be interpreted as including one or at least one, and elements or components in the singular also include plural forms, unless the quantity clearly refers to only the singular form.

[0045] The endpoints of the ranges and any values ​​disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0046] Example:

[0047] The preparation method of the CF / PEEK composite material based on multi-dimensional nanoparticle-modified carbon fibers in this embodiment is carried out by the following steps:

[0048] (1) First, commercial CF (CCF) fabrics were extracted with acetone at 80°C for 24 h using the Soxhlet extraction method to remove commercial sizing agents and impurities on the surface. After washing with deionized water, the fabrics were dried in an oven at 80°C for 24 h to obtain desized CF fabrics (BCF). The BCFs were placed in a 1.5 g / 100 mL Michaelis acid / ethanol solution (temperature 30°C) for 2 h, then washed with ethanol to remove unreacted Michaelis acid, and then dried at 80°C for 24 h to obtain activated CFs (ACFs) with carboxyl and hydroxyl groups on the surface.

[0049] Then, the ACFs were immersed in a PEI aqueous solution with a concentration of 1 mg / mL at 50 °C for 1 h, and then washed with deionized water and dried at room temperature overnight to obtain PEI-modified CFs.

[0050] (2) The purchased MXene with a concentration of 5 mg / mL was diluted to 1 mg / mL with deionized water, and then ultrasonicated for 30 min to obtain a uniformly dispersed MXene suspension.

[0051] The PEI-modified CF was then immersed in the MXene suspension for 30 min and dried in an oven at room temperature overnight to obtain a MXene-modified sample named MCF.

[0052] (3) 1 g of conductive carbon black (CB) and 1 g of polyethyleneimine (PEI) were added to 100 mL of deionized water. The mixed solution was then magnetically stirred at 60°C for 4 h and then reacted under ultrasonic conditions for 4 h. The reaction suspension was vacuum filtered through a 0.45 μm polyvinylidene fluoride filter membrane, and the filtrate was then washed with deionized water to remove unreacted polyethyleneimine. The washed polyethyleneimine-modified carbon black (PEI-CB) was dried in a vacuum oven at 40°C and ground for later use.

[0053] (4) First, PEI-CB was dispersed in deionized water to prepare a suspension with a concentration of 3 mg / mL and then sonicated for 2 h.

[0054] Then, the MCF was immersed in a PEI-CB suspension for 30 min and dried at 40°C to obtain a multidimensional nanoparticle-modified carbon fiber cloth, which was recorded as MC3-CF.

[0055] The micromorphologies of MXene (a, b), CB (c, d), and PEI-CB (e, f) were characterized by SEM, as shown in Figure 2. Figure 1As shown in the figure, the microstructure of MXene is a two-dimensional nanosheet structure, while both PEI-CB and CB are spherical and exhibit significant agglomeration. The unique layered structure and the synergistic effect of the nanoparticles can effectively fill the grooves on the carbon fiber surface, increase the roughness of the fiber, and thus enhance the mechanical interlocking effect between the fiber and the resin matrix.

[0056] Raman spectroscopy tests were performed on MXene, PEI-CB, desized CF fabric (BCF), CF modified with MXene only (MCF), and CF modified with MXene and PEI-CB (MC3-CF). The results are shown in Figure 2. Figure 2 As shown, the three characteristic peaks of MXene are located at 201.5 cm - 1. 384.6cm - 1 and 623cm - 1, these peaks also appear in the Raman spectra of MCF and MC3-CF. The 2D characteristic peak of PEI-CB (2677cm -1 ) appeared in the spectrum of MC3-CF. These results confirmed that MXene and PEI-CB were successfully deposited on the surface of CFs.

[0057] (5) The PEEK film was cleaned with ethanol under ultrasonic conditions and then dried in an oven at 80°C for 24 hours. The carbon fiber cloth modified with multidimensional nanoparticles and the PEEK film were alternately layered, with 8 layers of carbon fiber cloth modified with multidimensional nanoparticles and 9 layers of PEEK film (volume ratio 6:4), and then hot-pressed. Specifically, under the condition of 5 MPa, the film was preheated at 200°C for 30 minutes, then heated to 370°C and kept warm for 30 minutes, then cooled to 300°C and kept warm for 30 minutes, and cooled to room temperature to obtain a modified CF / PEEK composite material.

[0058] Comparative Example:

[0059] First, commercial CF (CCF) fabric was extracted with acetone at 80°C for 24 h using Soxhlet extraction to remove commercial sizing agents and impurities on the surface. After washing with deionized water, it was dried in an oven at 80°C for 24 h to obtain desized CF fabric (BCF).

[0060] The PEEK film was cleaned with ethanol under ultrasonic conditions and then dried in an oven at 80°C for 24 hours. BCF woven cloth and PEEK film were alternately layered, with 8 layers of BCF woven cloth and 9 layers of PEEK film (volume ratio 6:4), and then hot-pressed. Specifically, under conditions of 5 MPa, the film was preheated at 200°C for 30 minutes, then heated to 370°C and held for 30 minutes, then cooled to 300°C and held for 30 minutes, and then cooled to room temperature to obtain a CF / PEEK composite material.

[0061] The micromorphology of unmodified carbon fiber (comparative example) and modified carbon fiber (example) was characterized by SEM. Figure 3 The unmodified carbon fiber surface has obvious grooves. After modification, MXene nanosheets and PEI-CB nanoparticles are evenly deposited on the surface, and the fiber surface becomes significantly roughened, which is conducive to improving the mechanical interlocking effect between the fiber and the resin matrix.

[0062] The carbon fiber reinforced polyetheretherketone composite materials prepared in the examples of the present invention and the comparative examples were tested for flexural strength and interlaminar shear strength according to ASTM D7264 and ASTM D2344, respectively. Figure 4 The results show that the flexural strength of the modified composite material can reach 781.54MPa and the interlaminar shear strength is 67.1MPa.

[0063] The carbon fiber reinforced polyetheretherketone composite materials prepared in the examples and comparative examples of the present invention were tested for electromagnetic shielding performance in the X-band. The results are as follows: Figure 5 The results show that the electromagnetic shielding performance of the carbon fiber reinforced polyetheretherketone composite material prepared in the embodiment of the present invention reaches 29.28dB in the X-band.

[0064] The foregoing are merely preferred embodiments of the present invention. These embodiments are all different implementations based on the overall concept of the present invention. The scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for modifying carbon fibers with multidimensional nanoparticles, characterized in that: The method: S1: Activate the surface oxygen-containing functional groups of the desized CF fabric, and then soak it in a PEI aqueous solution under heating conditions to obtain PEI-modified CF; S2: immerse the PEI-modified CF in a MXene suspension and dry it at room temperature to obtain a MXene-modified CF, which is recorded as MCF. S3: adding CB and PEI to deionized water, magnetically stirring under heating conditions, then ultrasonically treating, filtering, washing, low-temperature drying, and grinding to obtain PEI-modified CB; the CB is conductive carbon black; S4: Dispersing the PEI-modified CB in deionized water to obtain a dispersion, then immersing the MCF in the dispersion, and drying at a low temperature to obtain a carbon fiber modified with multidimensional nanoparticles.

2. The method according to claim 1, characterized in that Desizing process of CF fabric in S1: Soxhlet extraction is performed in acetone under heating conditions, followed by water washing and drying, and surface oxygen-containing functional groups are activated by immersion in Michaeler's acid / ethanol solution with a PEI aqueous solution concentration of 0.5-1.5 g / L, a temperature of 40-60°C, and a immersion time of 0.5-1.5 h.

3. The method according to claim 1, characterized in that The concentration of MXene suspension in S2 is 0.5-1.5 g / L, and the immersion time is 20-40 min.

4. The method according to claim 1, wherein The mass ratio of CB and PEI in S3 is (0.5-1.5):1, the ratio of PEI to deionized water is 1 g: (80-120) mL, the magnetic stirring temperature is 50-70 ° C, the time is 3-5 h, and the ultrasonic treatment is 3-5 h.

5. The method according to claim 1, wherein The concentration of the dispersion in S4 is 1-5g / L, and the soaking time is 20-40min.

6. Multidimensional nanoparticle modified carbon fiber prepared by the method according to any one of claims 1 to 5.

7. A CF / PEEK composite material based on the multidimensional nanoparticle-modified carbon fiber according to claim 6.

8. The method for preparing the CF / PEEK composite material according to claim 7, characterized in that: The method: It is made by alternately laminating multi-dimensional nanoparticle modified carbon fibers and PEEK films and then hot pressing them.

9. The method according to claim 8, characterized in that The volume ratio of multidimensional nanoparticle modified carbon fiber and PEEK film is (7-5):

4. Hot pressing conditions: preheat at 150-250°C for 20-40min under 4-6MPa, heat to 350-400°C and keep warm for 20-40min, cool to 250-350°C and keep warm for 20-40min, and cool to room temperature.

10. Use of the CF / PEEK composite material according to claim 7 in the field of electromagnetic shielding.

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