A continuous hydrogen-bonded graphene-modified water-based carbon fiber sizing agent and its preparation method and application

Abstract

The present invention discloses a graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonding, which is prepared using the following raw materials in parts by weight: 10 to 40 parts of a conjugated polymer CzOH, 0.002 to 0.50 parts of amino-treated graphene oxide, 0.001 to 0.40 parts of photoacid, and 60 to 100 parts of water. The present invention can be applied to the preparation of carbon fiber / polyetheretherketone composite materials. The conjugated polymer CzOH in the present invention contains multiple hydroxyl side chains and oxetane side chains, and the hydroxyl groups can form hydrogen bonds with the amino groups of the amino-treated graphene oxide. At the same time, the conjugated polymer CzOH and the amino-treated graphene oxide can also form hydrogen bonds with the ether bonds and ketone bonds in the polyetheretherketone to form a continuous hydrogen bond connection structure. This structure allows the graphene to be evenly dispersed in the sizing agent to form a continuous and dense film, promote the contact between the carbon fiber and the resin molecular level and the interfacial interaction of the composite material, and effectively improve the interfacial performance of the composite material.

Description

Technical Field

[0001] The invention belongs to the technical field of sizing agents, and in particular relates to a graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonds, a preparation method thereof, and applications thereof. Background Art

[0002] Carbon fiber / polyetheretherketone (CF / PEEK) composite materials have good melting point fluidity and thermal stability above the melting point. Their excellent processing properties allow them to be prepared by a variety of methods. Therefore, they are increasingly widely used in the industrial field. The preparation process of CF / PEEK mainly includes carbon fiber pretreatment and composite material preparation. Its performance depends largely on the interface bonding between the matrix and the reinforcing fiber. However, PEEK has a high melting point and high melt viscosity, and the surface of untreated CF is smooth, resulting in poor interface bonding between the two. In order to improve the interface performance between the fiber and the resin, the surface treatment of carbon fiber by sizing can effectively improve the wear resistance and bundling of the fiber, increase the surface roughness and wettability of the fiber, and is simple to operate, low in cost, and easy to industrialize. It has become an indispensable step in the carbon fiber production process. Among them, water-based sizing agents are usually prepared by completely dissolving the modified resin in water. No external emulsifier is required, there is no demulsification phenomenon, the main component is only resin, the preparation process is simple and environmentally friendly, and it has become one of the hot spots in the current sizing agent research.

[0003] In addition, due to its unique physical and chemical properties, graphene, especially when added in small amounts to the carbon fiber surface or matrix resin, can significantly enhance the toughness of the resin matrix and improve the interfacial properties between the fiber and the resin. Introducing graphene to the carbon fiber / resin matrix interface through sizing is simple to operate and readily industrialized, offering a wide range of applications. However, graphene has poor dispersion stability in water and is prone to agglomeration and performance degradation when applied directly to a sizing agent without modification. Therefore, current methods for introducing graphene onto the carbon fiber surface mostly rely on chemical grafting and vapor deposition, and it cannot be introduced via water-based or emulsion-based sizing agents. Summary of the Invention

[0004] Based on this, the present invention has developed a water-based carbon fiber sizing agent with continuously hydrogen-bonded graphene-modified properties, which can evenly disperse graphene in the sizing agent and form a good connection between the graphene and the carbon fiber and the polyetheretherketone resin matrix. This water-based sizing agent significantly improves the performance and interface properties of carbon fiber / polyetheretherketone composite materials, overcoming the defects of existing products.

[0005] Figure 1 A schematic diagram showing the mechanism of continuous hydrogen bonding of the present invention is shown.

[0006] The continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent comprises the following components in parts by weight: 10 to 40 parts of a conjugated polymer CzOH, 0.002 to 0.50 parts of amino-modified graphene oxide, 0.001 to 0.40 parts of a photoacid, and 60 to 100 parts of water;

[0007] The chemical structure of the conjugated polymer CzOH is as follows:

[0008]

[0009] Wherein, x+y=0.5, y=1 to 40%; n is a natural number from 1 to 10,000;

[0010] The amino-modified graphene oxide is obtained by reacting graphene oxide with a silane coupling agent.

[0011] Furthermore, the graphene oxide has an average particle size of 5 to 30 μm and a thickness of 3.5 to 8 nm.

[0012] Another object of the present invention is to provide a method for preparing the continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent, comprising the following steps:

[0013] S1. Monomer 1, monomer 2, and monomer 3 are dissolved in an organic solvent, palladium acetate, tricyclohexylphosphine, and tetraethylammonium hydroxide aqueous solution are added under an inert atmosphere, stirred, phenylboric acid is added, and the reaction is carried out for 5 to 8 hours, followed by the addition of bromobenzene, and the reaction is carried out for 5 to 8 hours. After precipitation, filtration, and drying, intermediate product 1 is obtained;

[0014] S2. The intermediate product 1 was dissolved in tetrahydrofuran, filtered, distilled under reduced pressure, and then added to methanol, precipitated, filtered, and dried to obtain a solid polymer P1;

[0015] S3. The solid polymer P1 is dissolved in a mixed solution of tetrahydrofuran and N,N-dimethylformamide, diethanolamine is added, and the reaction is carried out under an inert atmosphere for 70 to 80 hours, and then impurities and unreacted raw materials are removed to obtain a conjugated polymer CzOH;

[0016] S4. dissolving the conjugated polymer CzOH in water, adding the amino-modified graphene oxide, mixing evenly, and then adding the photoacid to obtain the graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonds.

[0017] Wherein, in step S1, the chemical structure of the monomer 1 is as follows:

[0018]

[0019] The chemical structure of the monomer 2 is as follows:

[0020]

[0021] In step S1, the chemical structure of monomer 3 is as follows:

[0022]

[0023] Furthermore, the molar ratio of monomer 1, monomer 2 and monomer 3 is 0.5:0.1-0.4:0.4-0.1.

[0024] Furthermore, in step S1, the organic solvent is selected from aromatic hydrocarbon solvents. In some embodiments of the present invention, the organic solvent is selected from toluene.

[0025] Furthermore, in step S1, the amounts of palladium acetate, tricyclohexylphosphine, tetraethylammonium hydroxide, phenylboric acid and bromobenzene are 1 mol% to 5 mol% of monomer 1 respectively.

[0026] Specifically, in step S1, the molar ratio of palladium acetate, tricyclohexylphosphine and tetraethylammonium hydroxide is 1:1:1 to 1:1:3.

[0027] Furthermore, in step S1, the molar ratio of phenylboric acid to bromobenzene is 1:1.

[0028] Furthermore, in step S2, the volume ratio of the intermediate product 1 to tetrahydrofuran is 1:5 to 1:20.

[0029] Furthermore, in step S3, the molar ratio of the solid polymer P1 to diethanolamine is 1:2 to 1:3.

[0030] Another object of the present invention is to provide an application of the above-mentioned continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent in the field of polymer composite materials, specifically, the field of polymer composite materials is the field of carbon fiber / polyetheretherketone composite materials. In some application examples of the present invention, in the prepared carbon fiber / polyetheretherketone composite material, the carbon fiber needs to be first aminated and then sized with the sizing agent.

[0031] The present invention has the following beneficial effects:

[0032] (1) The present invention can be applied in the preparation of carbon fiber / polyetheretherketone composite materials. Since the conjugated polymer CzOH in the graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonds contains multiple hydroxyl side chains and oxetane side chains, the hydroxyl groups can form hydrogen bonds with the amino groups, so the hydroxyl groups of the conjugated polymer CzOH can form hydrogen bonds with the amino-groups of the amino-groups of the graphene oxide and the amino-groups of the carbon fibers in the composite material, respectively. At the same time, the conjugated polymer CzOH and the amino-groups of the graphene oxide can also form hydrogen bonds with the ether bonds and ketone bonds in the polyetheretherketone, forming a continuous hydrogen bond connection structure that is linked one ring to another. This structure allows the graphene to be evenly dispersed therein to form a continuous and dense film, promotes the contact between the carbon fiber and the resin molecular level and the interface interaction of the composite material, and can form a good sizing effect between the carbon fiber and the polyetheretherketone, effectively improving the interface performance of the composite material.

[0033] (2) The continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent of the present invention can be dissolved in water and can be sized on carbon fibers by solution processing methods such as dipping and brushing. It can be cured by heating or ultraviolet light irradiation to form a three-dimensional network structure with graphene uniformly dispersed therein, thereby increasing the dispersibility of graphene in the slurry. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the mechanism of continuous hydrogen bonding of the present invention;

[0035] Figure 1 In: 1. Aminated carbon fiber; 2. Graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonds; 3. Conjugated polymer CzOH; 4. Aminated graphene oxide; 5. PEEK; 6. Formed hydrogen bonds; 7. Aminated carbon fiber molecules; 8. Conjugated polymer CzOH molecules; 9. Aminated graphene oxide molecules; 10. PEEK molecules.

[0036] Figure 2 (a) Absorption spectra of the uncrosslinked polymer CzOH film before and after washing with distilled water; Figure 2 (b) Absorption spectra of the cross-linked polymer CzOH film before and after washing with distilled water;

[0037] Figure 2 In (a) to (b): Curve 1: absorption spectrum before washing with distilled water; Curve 2: absorption spectrum after washing with distilled water.

[0038] Figure 3 (a) is the cross-sectional micromorphology of the carbon fiber composite material prepared using desized carbon fibers in Comparative Example 1 of the present invention; Figure 3 (b) is the cross-sectional micromorphology of the carbon fiber composite material after being treated with a water-based carbon fiber sizing agent modified with graphene connected by continuous hydrogen bonds in Application Example 1 of the present invention.

[0039] Figure 4 This is a bar chart of shear strength test data of the carbon fiber composite materials prepared in Application Examples 1 to 4 and Comparative Example 1.

[0040] Figure 5 This is a bar chart of shear strength test data of the carbon fiber composite materials prepared in Application Examples 5 to 9 and Comparative Example 2. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0043] Unless otherwise mentioned, the preparation of the carbon fiber / polyetheretherketone composite materials in the embodiments of the present invention is conventional means well known to those skilled in the art.

[0044] Unless otherwise specified, the parts in the examples of the present invention are parts by weight.

[0045] The synthetic route of the conjugated polymer CzOH in the embodiment of the present invention, poly{3,6-[9-(6-(3-hexyloxymethyl-3-ethyl-oxetane))carbazole]-co-3,6-(9-ethylhexyl-carbazole)-co-2,7-[9,9′-bis[(6-N,N-diethanolamino)-hexyl]fluorene]} (referred to as conjugated polymer CzOH), is as follows:

[0046]

[0047] Among them, SPC stands for Suzuki polycondensation;

[0048] Monomer 1: 3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9-(6-(3-hexyloxymethyl-3-ethyl-oxetane))carbazole;

[0049] Monomer 2: 3,6-dibromo-9-ethylhexyl-carbazole;

[0050] Monomer 3: 2,7-dibromo-bis[9,9'-bis(6,6'-bromohexyl)]fluorene;

[0051] Polymer P1: poly{3,6-[9-(6-(3-hexyloxymethyl-3-ethyl-oxetane))carbazole]-co-3,6-(9-ethylhexyl-carbazole)-co-2,7-[9,9′-di(6,6′-bromohexyl)fluorene]}.

[0052] The photoacid in the embodiment of the present invention is [2-(4-methoxyphenylvinyl)-4,6-bis(trichloromethyl)-1,3,5-triazine].

[0053] The graphene oxide in the embodiment of the present invention has an average particle size of 5 μm and an average thickness of 3.5 nm.

[0054] The preparation method of the amination-modified graphene oxide in the application example of the present invention is as follows:

[0055] Disperse 50 mg of graphene oxide in 100 mL of ethanol-water solution (ethanol:water = 50 mL:50 mL) and ultrasonically disperse at room temperature for 2 hours. Then, under magnetic stirring, add 1 mL of silane coupling agent KH-550 dropwise to the graphene oxide solution and react at 70°C for 24 hours.

[0056] After the reaction is completed, the amination-modified graphene oxide solution is repeatedly centrifuged with ethanol to remove unreacted silane coupling agent, and then vacuum-dried at 50° C. for 24 h to obtain amination-modified graphene oxide.

[0057] The preparation method of the amination carbon fiber in the application example of the present invention is as follows:

[0058] 100 g of carbon fiber was desized in 1000 mL of acetone in a water bath at 80 ° C for 48 h, then wound on a polytetrafluoroethylene rod and placed in a mixed acid of 200 mL of concentrated sulfuric acid and concentrated nitric acid (the volume ratio of concentrated sulfuric acid to concentrated nitric acid was 3:1), refluxed at 70 ° C for 2 h, and then rinsed with a large amount of deionized water. Then, it was placed in an oven and dried at 100 ° C for 3 h to obtain acidified carbon fiber;

[0059] The acidified carbon fiber was then immersed in 400 mL of a mixed solution of thionyl chloride and dimethylformamide (the volume ratio of thionyl chloride to dimethylformamide was 20:1), and the mixture was reacted at 80°C under nitrogen protection for 24 hours. After that, the unreacted thionyl chloride was removed by rinsing with tetrahydrofuran, and the treated carbon fiber was placed in a vacuum drying oven at 50°C for 24 hours to obtain chlorinated carbon fiber.

[0060] The chlorinated carbon fibers were immersed in 300 mL of ethylenediamine solution and stirred at 110°C for 72 hours. After cooling to room temperature, the reaction product was washed with anhydrous tetrahydrofuran and filtered until the solution was clear. After drying with nitrogen, the product was placed in a vacuum oven at 70°C to obtain the amino-modified carbon fibers.

[0061] Example 1

[0062] A continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent, the preparation method of which is as follows:

[0063] S1. 0.3915 g (0.5 mmol) of monomer 1, 0.1804 g (0.4 mmol) of monomer 2, and 0.0651 g (0.1 mmol) of monomer 3 were dissolved in 20 mL of toluene. 0.005 mmol of palladium acetate, 0.005 mmol of tricyclohexylphosphine, and 0.01 mmol of tetraethylammonium hydroxide (prepared into a 20 wt% aqueous solution) were added under argon protection. After stirring under reflux for 48 h under argon atmosphere, 0.005 mmol of phenylboric acid was added and reacted for 6 h. 0.005 mmol of bromobenzene was then added and reacted for 6 h. After the reaction, the product was cooled to room temperature and poured into methanol for precipitation. The precipitate was filtered and dried in vacuo to obtain intermediate product 1.

[0064] S2. 5 g of intermediate product 1 was dissolved in 250 mL of tetrahydrofuran, filtered through a 0.45 μm pore size polytetrafluoroethylene (PTFE) filter, concentrated by distillation under reduced pressure, and then added dropwise to 250 mL of methanol. The mixture was then precipitated, filtered, and dried under vacuum to obtain polymer P1.

[0065] S3. 2.0 mmol of polymer P1 was dissolved in 100 mL of a mixture of tetrahydrofuran and N,N-dimethylformamide (volume ratio of 1:1). Diethanolamine was added (the molar ratio of polymer P1 to diethanolamine was 1:2). The reaction was allowed to react at room temperature under an argon atmosphere for 72 h. The reaction system was then poured into 500 mL of n-hexane for precipitation. The mixture was filtered, air-dried overnight, and then vacuum-dried for 24 h to obtain a light green solid conjugated polymer CzOH (hydroxyl content of 10% (i.e., y = 10% in the chemical structure of CzOH)).

[0066] S4. Take 20g of conjugated polymer CzOH and dissolve it in 100g of water, add 0.12g of amino-treated graphene oxide, mix evenly by ultrasonication to obtain a complex solution, and add 0.2g of photoacid [2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine] to this solution to obtain the continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent.

[0067] Examples 2 to 4

[0068] A continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent, the preparation process and preparation raw materials are the same as those in Example 1, the only difference being that the hydroxyl content of the polymer CzOH component in the continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent of Examples 2 to 4 is 20%, 30%, and 40% (i.e., in the chemical structure of CzOH, y = 20%, 30%, and 40%), that is, the feeding amounts of monomer 1, monomer 2, and monomer 3 in step S1 of Examples 2 to 4 are respectively changed to:

[0069] Example 2: 0.5 mmol monomer 1, 0.3 mmol monomer 2, 0.2 mmol monomer 3;

[0070] Example 3: 0.5 mmol monomer 1, 0.2 mmol monomer 2, 0.3 mmol monomer 3;

[0071] Example 4: 0.5 mmol monomer 1, 0.1 mmol monomer 2, 0.4 mmol monomer 3.

[0072] Examples 5 to 9

[0073] A continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent, the preparation process and preparation raw materials are the same as those of Example 2, and Examples 5 to 9 use a conjugated polymer CzOH with a hydroxyl content of 20% (i.e., y=20% in the chemical structure of CzOH) as a dispersed matrix. The difference is that in step S4 of Examples 5 to 9, the total weight of the components is the same as that of Example 2, and then the weight of the conjugated polymer CzOH is fixed at 16% of the total weight of the sizing agent, the photoacid is 0.17% of the total weight of the sizing agent, and the contents of the amino-modified graphene oxide in Examples 5 to 9 are 0.05%, 0.10%, 0.15%, 0.20% and 0.25% of the total weight of the sizing agent, respectively.

[0074] Application Examples 1 to 9

[0075] A carbon fiber composite material is prepared by using the continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent prepared in Examples 1 to 9 as a sizing agent:

[0076] S1. 100 g of amino-treated carbon fiber was immersed in 500 mL of sizing agent for 30 min, removed, and dried at 80 ° C for 4 h to remove unreacted material to obtain sizing-treated carbon fiber;

[0077] S2. The polyetheretherketone powder was hot-pressed to obtain a polyetheretherketone film having a thickness of 0.5 mm;

[0078] S3. The sizing-treated carbon fiber is longitudinally wound on an iron frame and compounded with a polyetheretherketone film to prepare a prepreg. The prepreg is then cut into appropriate sizes and placed in a mold coated with a release agent (the laying direction of the fibers is 0°) for hot pressing. After the flat vulcanizer is heated from room temperature to 380°C, it is kept at this temperature for 30 minutes and pressurized to 5MPa to melt the polyetheretherketone resin and fully infiltrate the carbon fiber. The exhaust treatment is then performed three times, with an interval of 1 minute each time. After the exhaust is completed, the temperature is lowered to room temperature at a rate of 15°C / min, and a carbon fiber composite material with a thickness of 2mm is obtained after demolding.

[0079] Comparative Example 1

[0080] A carbon fiber composite material, wherein desizing carbon fiber and polyetheretherketone are laminated to form a carbon fiber composite material with a thickness of 2 mm, and the preparation method is the same as the preparation method shown in steps S2 to S3 of application examples 1 to 9, except that the sizing carbon fiber is replaced by desizing carbon fiber. The desizing operation of the carbon fiber is completed in a Soxhlet extractor, specifically under the conditions of reflux 100 g of carbon fiber in 500 mL of acetone in an 80°C water bath for 48 hours, and then vacuum drying the carbon fiber in a vacuum drying oven at 40°C for 24 hours to obtain the desizing carbon fiber.

[0081] Comparative Example 2

[0082] A carbon fiber composite material. The preparation process and raw materials of the sizing agent used in Comparative Example 2 are the same as those in Example 2. A conjugated polymer CzOH with a hydroxyl content of 20% (i.e., y = 20% in the chemical structure of CzOH) is used as the dispersed matrix, and the weight of the conjugated polymer CzOH is fixed at 15% of the total weight of the sizing agent. The only difference is that the sizing agent in Comparative Example 2 does not contain amino-treated graphene oxide. The carbon fiber composite material is then prepared using the same method as in the application example.

[0083] Test Example 1

[0084] To illustrate the properties of the polymer CzOH of the present invention, the solubility and thermal crosslinking properties of the polymer CzOH prepared in Example 1 of the present invention were tested:

[0085] The polymer CzOH was dissolved in water. The solubility of the polymer in water at 25°C was 40 g.

[0086] Take 20g of polymer CzOH and dissolve it in 100g of water. Heat it on a quartz plate at 130℃ to form a film. Wash the film with distilled water at room temperature. The absorption spectra before and after washing are as follows: Figure 2As shown in (a), curves 1 and 2 represent the absorption spectra before and after distilled water washing, respectively. By comparing curves 1 and 2, it can be seen that nearly 90% of the polymer is eluted.

[0087] Take another 20g polymer CzOH and dissolve it in 100g water, add 0.01g of photoacid, stir evenly, and heat it at 130℃ on a quartz plate to form a film. Wash the film with distilled water. The absorption spectra before and after washing are as follows: Figure 2 By comparing curves 1 and 2, it can be seen that the film is almost not eluted, indicating that the polymer CzOH undergoes thermal cross-linking under the initiation of photoacid, forming a network structure with excellent solvent resistance.

[0088] Test Example 2

[0089] Mechanical properties tests were performed on the carbon fiber composite materials prepared in Examples 1 to 9 and Comparative Examples 1 and 2:

[0090] The interlaminar shear strength of the composites was characterized using the three-point short-arm beam bending method on a Z100 universal testing machine (Zwick, Germany) according to ASTM D2344. The composite specimens measured 15 mm × 4 mm × 2 mm, with an 8 mm span. The indenter loading rate was 1 mm / min. Tests were conducted at room temperature (25 ± 2°C). The interlaminar shear strength was the average of five valid data points.

[0091] The shear strength test results are as follows:

[0092] Figure 3 (a) shows the cross-sectional microstructure of the carbon fiber composite material prepared using desized carbon fibers in Comparative Example 1 of the present invention; Figure 3 (b) shows the cross-sectional microstructure of the carbon fiber composite material after being treated with a water-based carbon fiber sizing agent modified with graphene connected by continuous hydrogen bonds in Application Example 1 of the present invention.

[0093] from Figure 3 (a) It can be seen that for the desizing carbon fiber composite material, a large amount of carbon fibers are pulled out from the matrix resin, no excess resin remains on the carbon fiber surface, and there are many holes remaining in the cross section, indicating that the interface bonding between the carbon fiber and the resin is poor. Figure 3 (b) The carbon fiber modified with a water-based carbon fiber sizing agent with continuous hydrogen bonds significantly improves the interfacial bonding between the carbon fiber and the resin, with no noticeable gaps in the cross section. The carbon fiber and resin break simultaneously, with virtually no carbon fiber pullout.

[0094] Figure 4 This is a bar chart of shear strength test data of the carbon fiber composite materials prepared in Application Examples 1 to 4 and Comparative Example 1.

[0095] from Figure 4 The data show that the average interlaminar shear strength of the unsized carbon fiber composite material is 75.3 MPa, while the average interlaminar shear strength of the carbon fiber composite material treated with the sizing agent of the present invention in Application Example 1 is 89.5 MPa, which is 18.9% higher than that of the unsized composite material.

[0096] The hydroxyl content of the conjugated polymer CzOH component in the sizing agent used in Application Examples 2 to 4 is 20%, 30%, and 40%, respectively (i.e., in the chemical structure of CzOH, y=20%, 30%, and 40%), and the average interlaminar shear strength of the prepared carbon fiber composites is higher than that of Comparative Example 1. As the content of hydroxyl functional groups in the polymer CzOH increases, the interlaminar shear strength of the composite material increases. When the hydroxyl content is 20%, the interface performance is optimal, and the average interlaminar shear strength reaches 95.4MPa, which is 26.7% higher than that of the carbon fiber composite material of Comparative Example 1. This is because the strong composite material interface given by the continuous hydrogen bond structure formed between the present invention and the carbon fiber, graphene, and PEEK can limit the molecular motion of the polyetheretherketone resin at the interface, so that it needs to absorb more energy when subjected to shear load. However, when the content of hydroxyl functional groups in the sizing agent continues to increase, the interlaminar shear strength decreases slightly. This may be because the number of hydroxyl groups in the present invention that can form hydrogen bonds with polyetheretherketone has reached saturation, and further increasing the hydroxyl content has little effect on improving the interface performance, and is even not conducive to the bonding of carbon fiber and resin, resulting in a decrease in the interlaminar shear strength of the composite material.

[0097] Figure 5 This is a bar chart of shear strength test data of the carbon fiber composite materials prepared in Application Examples 5 to 9 and Comparative Example 2.

[0098] from Figure 5 The effect of sizing agents with different contents of amino graphene on the interlaminar shear strength of carbon fiber composites can be intuitively seen. In the table, the contents of amino graphene oxide in the sizing agents used in Comparative Example 2 and Application Examples 5 to 9 are 0%, 0.05%, 0.10%, 0.15%, 0.20% and 0.25% of the total mass of the sizing agent, respectively.

[0099] from Figure 5It can be seen that due to the graphene oxide not containing amination in the sizing agent used in comparative example 2, the average interlaminar shear strength value of composite material is the lowest, which is 83.6MPa. When the content of amination graphene oxide is 0.15%, it is 98.7MPa that composite material has shown the best average interlaminar shear strength, which is improved by 17.9% compared with the composite material (83.7MPa) in comparative example 2, and improved by 31.1% compared with the composite material (75.3MPa) in comparative example 1, illustrating that the structure of the continuous hydrogen bond obtained after modification by the sizing agent of the present invention can effectively improve the interlaminar shear strength of composite material. But when carbon fiber is processed with the sizing agent of higher amination graphene oxide content, there is a downward trend in the interlaminar shear strength of composite material, which may be because when graphene content is larger, it is easy to form agglomeration on carbon fiber surface, and graphene becomes a stress concentration point in composite material, and when subjected to external load, fracture damage will first occur here, but its reinforcement to interface will be weakened.

[0100] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0101] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent, characterized in that: The continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent comprises the following components in parts by weight: 10 to 40 parts of a conjugated polymer CzOH, 0.002 to 0.50 parts of amino-modified graphene oxide, 0.001 to 0.40 parts of a photoacid, and 60 to 100 parts of water; The chemical structure of the conjugated polymer CzOH is as follows: Wherein, x+y=0.5, y=0.01-0.4; n is a natural number from 1 to 10000; The amino-modified graphene oxide is obtained by reacting graphene oxide with a silane coupling agent.

2. The graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonding according to claim 1, characterized in that The graphene oxide has an average particle size of 5 to 30 μm and a thickness of 3.5 to 8 nm.

3. The method for preparing the continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent according to any one of claims 1 to 2, characterized in that: The steps include: S1. Monomer 1, monomer 2, and monomer 3 are dissolved in an organic solvent, palladium acetate, tricyclohexylphosphine, and tetraethylammonium hydroxide aqueous solution are added under an inert atmosphere, stirred, phenylboric acid is added, and the reaction is continued for 5 to 8 hours, followed by the addition of bromobenzene, and the reaction is continued for 5 to 8 hours. After precipitation, filtration, and drying, intermediate product 1 is obtained; S2. The intermediate product 1 was dissolved in tetrahydrofuran, filtered, distilled under reduced pressure, and then added to methanol, precipitated, filtered, and dried to obtain a solid polymer P1; S3. The solid polymer P1 is dissolved in a mixed solution of tetrahydrofuran and N,N-dimethylformamide, diethanolamine is added, and the reaction is carried out under an inert atmosphere for 70 to 80 hours, and then impurities and unreacted raw materials are removed to obtain a conjugated polymer CzOH; S4. The conjugated polymer CzOH is dissolved in water, the amino-modified graphene oxide is added, mixed evenly, and then the photoacid is added to obtain the continuous hydrogen-bonded graphene-modified waterborne carbon fiber sizing agent; Wherein, in step S1, the chemical structure of the monomer 1 is as follows: The chemical structure of the monomer 2 is as follows: The chemical structure of the monomer 3 is as follows:

4. The graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonding according to claim 3, characterized in that In step S1, the molar ratio of monomer 1, monomer 2 and monomer 3 is 0.5:0.1-0.4:0.4-0.

1.

5. The graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonding according to claim 3, characterized in that In step S1, the amounts of palladium acetate, tricyclohexylphosphine, tetraethylammonium hydroxide, phenylboric acid and bromobenzene are 1 mol% to 5 mol% of monomer 1, respectively.

6. The method for preparing a graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonding according to claim 3, wherein In step S1, the molar ratio of palladium acetate, tricyclohexylphosphine and tetraethylammonium hydroxide is 1:1:1 to 1:1:

3.

7. The method for preparing a graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonding according to claim 3, wherein In step S2, the volume ratio of the intermediate product 1 to tetrahydrofuran is 1:5 to 1:

20.

8. The method for preparing a graphene-modified water-based carbon fiber sizing agent with continuous hydrogen bonding according to claim 3, wherein: In step S3, the molar ratio of the solid polymer P1 to diethanolamine is 1:2 to 1:

3.

9. Application of the continuously hydrogen-bonded graphene-modified water-based carbon fiber sizing agent according to claim 1 in the field of polymer composite materials.

Images