High-strength fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material and preparation method thereof

Abstract

The application belongs to the technical field of polymer composites, and provides a high-strength anti-fatigue continuous aramid fiber / unsaturated polyester resin composite material and a preparation method thereof. The high-strength anti-fatigue continuous aramid fiber / unsaturated polyester resin composite material is prepared by taking unsaturated polyester resin as a matrix, taking polyethylene imine-polydopamine modified continuous aramid fiber as a reinforcing body, and using Michael addition reaction and Schiff base reaction of polydopamine and polyethylene imine to graft polydopamine and polyethylene imine onto the continuous aramid fiber, and at the same time, the modified continuous aramid fiber is arranged in the collagen fiber arrangement structure of the dense bone, so that the high-strength anti-fatigue continuous aramid fiber / unsaturated polyester resin composite material is prepared. The interfacial bonding strength reaches 40.60 MPa, the tensile strength reaches 959.07 MPa, the fatigue life under 600 MPa reaches 760,000 times, the fatigue life under 500 MPa reaches 10,470,000 times, and the fatigue life under 400 MPa reaches 87,100,000 times.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer composite material, and relates to modification of fibers in a composite material and mechanical properties of the composite material, in particular to a high-strength anti-fatigue continuous aramid fiber / unsaturated polyester resin composite material and a preparation method thereof. BACKGROUND

[0002] High-performance continuous fiber reinforced polymer composite material is a composite material formed by combining high-strength continuous fibers and a resin matrix. The resin matrix serves as an adhesive for the continuous fiber reinforcement, responsible for transmitting the load between the fibers, and the continuous fibers serve as the reinforcement of the matrix, which is the main supporter of the high strength of the continuous fiber composite material. High-performance continuous fiber reinforced polymer composite material gradually replaces traditional structural materials such as metals due to its superior mechanical properties, good environmental stability, and lightweight characteristics. Continuous aramid fiber, as an organic fiber composite material, has attracted much attention in continuous fiber reinforced composite materials. However, continuous aramid fiber, although excellent in performance, has poor adhesion to most resin matrices due to its high orientation and inert surface. In order to improve this shortcoming of aramid fiber, researchers have improved the interfacial bonding performance of aramid fiber and resin matrix by modifying the surface of aramid fiber.

[0003] At the same time, the arrangement structure of the fibers in the composite material is crucial to the mechanical properties of the composite material. So far, many researchers have prepared fiber composite materials with excellent strength and toughness by mimicking natural structures, which have broad application prospects in various fields. SUMMARY

[0004] In order to improve the mechanical properties of continuous aramid fiber / unsaturated polyester resin composite material, the present application provides a high-strength anti-fatigue continuous aramid fiber / unsaturated polyester resin composite material and a preparation method thereof.

[0005] The present application simply modifies the continuous aramid fiber, enhances the bonding strength between the aramid fiber and the unsaturated polyester resin matrix, and improves the tensile strength and anti-fatigue performance of the continuous aramid fiber / unsaturated polyester resin composite material.

[0006] The present application is realized by the following technical solutions: a preparation method of a high-strength anti-fatigue continuous aramid fiber / unsaturated polyester resin composite material, in which unsaturated polyester resin is used as the matrix, and polyethyleneimine-polydopamine modified continuous aramid fiber is used as the reinforcement. The modified continuous aramid fiber is arranged in the collagen fiber arrangement structure of dense bone to prepare the high-strength anti-fatigue continuous aramid fiber / unsaturated polyester resin composite material.

[0007] Further, the method comprises the following steps:

[0008] (1) Surface modification of continuous aramid fiber: continuous aramid fiber is soaked in ethyl acetate for 24 hours for surface pretreatment to remove impurities on the surface of the fiber, and then dried;

[0009] A mixed solution of polydopamine and polyethyleneimine is prepared in a mass ratio of 1:1, and tris(hydroxymethyl) aminomethane is added to adjust the pH to 8.5, and then stirred again to obtain a modified mixed solution;

[0010] The pretreated continuous aramid fiber is immersed in the continuous aramid fiber, taken out after being kept at 37℃ and 180 rpm for 24 hours, and then washed with deionized water to remove impurities attached to the surface of the fiber, and then dried to obtain polyethyleneimine-polydopamine modified continuous aramid fiber;

[0011] (2) Glue dipping: a promoter, methyl ethyl ketone peroxide, and an initiator, cobalt naphthenate, are added to the unsaturated polyester resin as a glue solution, and the mass ratio of unsaturated polyester resin, methyl ethyl ketone peroxide and cobalt naphthenate is 100:1:2;

[0012] The polyethyleneimine-polydopamine modified continuous aramid fiber is immersed in the glue solution at room temperature, the excess resin is scraped off, and the immersed polyethyleneimine-polydopamine modified continuous aramid fiber is arranged according to the arrangement mode of the collagen fibers between the dense bones, and then placed in a dry mold;

[0013] (3) Curing: a contact pressure of 10 MPa is applied at the beginning of the mold closing, and then the mold is placed in an oven after the unsaturated polyester resin becomes a gel state, and cured at 60℃ for 12 hours to obtain a high-strength and fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material.

[0014] Further, the aramid fiber is para-aramid fiber, Kevlar 29, 1500 D.

[0015] Further, in the preparation of the mixed solution of polydopamine and polyethyleneimine in step (1), the concentration of the polydopamine solution is 2 mg / ml, the concentration of the polyethyleneimine is 2 mg / ml, and the mass concentration ratio of the polydopamine to the polyethyleneimine is 1:1.

[0016] In step (2), the unsaturated polyester resin is an unsaturated polyester of type 191, and during the curing and molding of the resin, a promoter is first added to the unsaturated polyester resin, and then an initiator is added after uniform mixing, and the continuous aramid fiber is immersed in the glue before the resin reaches the gel state.

[0017] The application also provides a high-strength and fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material prepared by the above method.

[0018] The application provides an easy-to-operate continuous aramid fiber modification method and a biomimetic structure of a continuous aramid fiber / unsaturated polyester resin composite material.

[0019] The aramid fiber is para-aramid fiber, Kevlar 29, 1500 D, and the method can also be applied to other existing aramid fibers, and the treatment of the application will not adversely affect these aramid fibers, and these aramid fibers are also within the protection scope of the application.

[0020] The continuous aramid fiber is chemically modified by dopamine and polyethylene imine, the modification preparation conditions are mild, the operation is simple, and the industrial scale production is easy to realize; the continuous aramid fiber is surface modified by simple and mild operation, the interface bonding capacity of the continuous aramid fiber and the unsaturated polyester resin is improved, the continuous aramid fiber / unsaturated polyester resin composite material is prepared by imitating the layer-by-layer arrangement structure of collagen fibers in dense bone, and the continuous aramid fiber / unsaturated polyester resin composite material has good tensile strength and fatigue resistance; the high-strength and fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material provided by the application is expected to be widely applied to main bearing materials in many technical fields such as deep sea mining, medical devices, aerospace and the like.

[0021] The modified aramid fiber is arranged to prepare the aramid fiber / unsaturated polyester resin composite material with high strength and fatigue resistance, the interface bonding strength of the material reaches 40.60 MPa, the tensile strength reaches 959.07 MPa, the interface bonding strength is increased by 82.47% and the tensile strength is increased by 34.19% compared to the unmodified continuous aramid fiber composite material; the fatigue life under 600 MPa reaches 760,000 times, which is increased by 385% compared to the unmodified continuous aramid fiber composite material (160,000 times); the fatigue life under 500 MPa reaches 10,470,000 times, which is increased by 273% compared to the unmodified continuous aramid fiber composite material (2,810,000 times); and the fatigue life under 400 MPa reaches 87,100,000 times, which is increased by 247% compared to the unmodified continuous aramid fiber composite material (25,110,000 times). Moreover, the process is simple and easy to scale production, and the cost is low, and the application has important significance in scientific research and practical application fields. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1Stress-strain curves (A), tensile strength (B), Young's modulus (C), elongation at break (D) of unsaturated polyester resin under different curing processes;

[0023] Figure 2 Surface scanning electron microscope picture of polyethyleneimine-polydopamine modified continuous aramid fiber (PEI-PDA-AF) in Example 1 of the present application;

[0024] Figure 3 Stress-strain curve (A) and interfacial bonding strength (B) of continuous aramid fiber / unsaturated polyester resin cross-ply composite material of the present application;

[0025] Figure 4 Tensile fracture cross-section scanning electron microscope pictures of continuous aramid fiber / unsaturated polyester resin cross-ply composite material of the present application, A is the tensile fracture cross-section scanning electron microscope picture of polyethyleneimine-polydopamine modified aramid fiber / unsaturated polyester resin cross-ply composite material, B is the tensile fracture cross-section scanning electron microscope picture of polydopamine-aramid fiber / unsaturated polyester resin cross-ply composite material, and C is the tensile fracture cross-section scanning electron microscope picture of unmodified aramid fiber / unsaturated polyester resin cross-ply composite material;

[0026] Figure 5 Stress-strain curve (A) and tensile strength (B) of continuous aramid fiber / unsaturated polyester resin composite material of the present application;

[0027] Figure 6 Tensile fracture cross-section scanning electron microscope pictures of continuous aramid fiber / unsaturated polyester resin composite material of the present application, A is the tensile fracture cross-section scanning electron microscope picture of polyethyleneimine-polydopamine modified aramid fiber / unsaturated polyester resin composite material, B is the tensile fracture cross-section scanning electron microscope picture of polydopamine-aramid fiber / unsaturated polyester resin composite material, and C is the tensile fracture cross-section scanning electron microscope picture of unmodified aramid fiber / unsaturated polyester resin composite material;

[0028] Figure 7 Fatigue life curve of polyethyleneimine-polydopamine modified aramid fiber / unsaturated polyester resin composite material (PEI-PDA-AF / UP) and unmodified aramid fiber / unsaturated polyester resin composite material (AF / UP) of the present application;

[0029] Figure 8 Surface scanning electron microscope picture of polydopamine modified continuous aramid fiber in Comparative Example 1 of the present application;

[0030] Figure 9 Surface scanning electron microscope picture of unmodified continuous aramid fiber in Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the scope of the present application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs, and the materials referred to in this disclosure are incorporated by reference.

[0033] All equivalent technologies of the described specific embodiments that can be realized by routine experiments and that are realized by those of ordinary skill in the art are included in the present application.

[0034] The experimental methods in the following embodiments are all routine methods unless otherwise specified. The instruments and equipment used in the following embodiments are all routine laboratory instruments and equipment unless otherwise specified. The experimental materials used in the following embodiments are all purchased from routine biochemical reagent stores unless otherwise specified.

[0035] The curing process optimization experiment of the unsaturated polyester resin: the optimal curing process of the polyethyleneimine-polydopamine-continuous aramid fiber / unsaturated polyester resin composite material is determined by determining the optimal curing process of the unsaturated polyester resin. The curing temperature and curing time are included, and the specific content is as follows:

[0036] The accelerator methyl ethyl ketone peroxide and the initiator cobalt naphthenate are added in the unsaturated polyester resin, and the mass ratio of the unsaturated polyester resin, the methyl ethyl ketone peroxide and the cobalt naphthenate is 100:1:2. After the mixture is stirred uniformly, it is poured into a dumbbell-shaped mold and left to stand for 30 minutes to a gel state.

[0037] The mold is placed at 25℃ for 12 hours, at 60℃ for 2 hours, at 60℃ for 6 hours, at 60℃ for 12 hours and at 60℃ for 24 hours respectively, and then taken out, and the tensile strength is measured when it returns to room temperature.

[0038] As Figure 1The stress-strain curve, tensile strength, Young's modulus, and elongation at break of the unsaturated polyester resin under different curing processes are shown. As can be seen from the figure, the tensile strength of the unsaturated polyester resin significantly increases and the elongation at break significantly decreases when the temperature increases from 25℃ to 60℃, which shows that temperature is the main influencing factor in the curing process, and therefore 60℃ is selected as the curing temperature. When the curing is carried out at 60℃, the tensile strength of the unsaturated polyester resin cured for 12 hours and 24 hours is 53.53 MPa and 56.77 MPa, respectively, and the difference between the two is not large. Considering the experimental cost, the present application selects 12 hours as the curing time of the continuous aramid fiber / unsaturated polyester resin composite material. Based on the above experimental examples, the present application selects the optimal curing process as follows: the resin is cured at 60℃ for 12 hours after the gel state is reached.

[0039] Example 1: Preparation and performance characterization of a polyethyleneimine-polydopamine modified continuous aramid fiber / unsaturated polyester resin composite material, the specific content is as follows:

[0040] The continuous aramid fiber is soaked in ethyl acetate for 24 hours to remove impurities on the surface of the fiber after surface pretreatment and drying. A solution of 2 mg / ml dopamine and polyethyleneimine with a ratio of 1:1 (pH = 8.5) is prepared, and the continuous aramid fiber is placed in the solution and soaked at 37℃ for 24 hours. After the reaction is completed, the continuous aramid fiber is taken out, washed with deionized water to clean the surface, and placed in a 60℃ oven for drying for 12 hours. The polyethyleneimine-polydopamine modified continuous aramid fiber is obtained after drying. Figure 2 The scanning electron microscope picture of the polyethyleneimine-polydopamine modified continuous aramid fiber shows that the fiber surface is rough and a large area of dense coating appears.

[0041] The polyethyleneimine-polydopamine modified continuous aramid fiber is dipped in glue, the excess resin is scraped off, and is laid horizontally in the mold of the horizontal tow composite material. The unsaturated polyester resin is slowly injected into the mold to fill it, and a clean release paper is covered on it. A contact pressure of 10 MPa is applied at the beginning. After the resin reaches the gel state, it is placed in an oven for curing at 60℃ for 12 hours. The interfacial bonding strength of the polyethyleneimine-polydopamine modified continuous aramid fiber / unsaturated polyester resin horizontal tow composite material is shown in Figure 3 , and the interfacial bonding strength reaches 40.60 MPa. Figure 4 (A) is the scanning electron microscope picture of the broken cross section of the polyethyleneimine-polydopamine modified continuous aramid fiber / unsaturated polyester resin horizontal tow composite material. There is more resin residue on the surface of the continuous aramid fiber, and the fiber surface peeling off the resin matrix shows a multi-layer peeling phenomenon.

[0042] The polyethyleneimine-polydopamine modified continuous aramid fiber was dipped, and the excess resin was scraped off. The dipped fiber was arranged in the interlaminar collagen fiber layer of the biomimetic compact bone in a 30° layer-by-layer stacking manner in a mold. An initial contact pressure of about 10 MPa was applied. After waiting for the resin to gel, the resin was placed in an oven for curing at 60°C for 12 hours. The tensile stress-strain and tensile strength of the polyethyleneimine-polydopamine modified continuous aramid fiber / unsaturated polyester resin composite are shown in Figure 5 , and the tensile strength reaches 959.07 MPa. Figure 6 (A) is a tensile fracture cross-section scanning electron microscope picture of the polyethyleneimine-polydopamine modified continuous aramid fiber / unsaturated polyester resin composite. The filament structure generated by the fiber pulling out of the resin can be clearly observed, and more energy is consumed. The fatigue life curve of the polyethyleneimine-polydopamine modified continuous aramid fiber / unsaturated polyester resin composite is shown in Figure 7 . As the stress level increases, the fatigue life gradually decreases. The fatigue life at 600 MPa reaches 760,000 times, the fatigue life at 500 MPa reaches 10,470,000 times, and the fatigue life at 400 MPa reaches 87,100,000 times.

[0043] Comparative Example 1: Preparation and performance characterization of a polydopamine modified continuous aramid fiber / unsaturated polyester resin composite. Compared with Example 1, the polyethyleneimine graft modification was not performed on the polydopamine modified continuous aramid fiber. The specific content is as follows:

[0044] The continuous aramid fiber was soaked in ethyl acetate for 24 hours to remove impurities on the surface of the fiber. A 2 mg / ml dopamine and polyethyleneimine solution (pH = 8.5) was prepared, and the continuous aramid fiber was placed in the solution. The fiber was soaked at 37°C for 24 hours. After the reaction was completed, the fiber was taken out, washed with deionized water, and dried in a 60°C oven for 12 hours to obtain the polydopamine modified continuous aramid fiber. Figure 8 The scanning electron microscope picture of the polydopamine modified continuous aramid fiber shows that the fiber surface is rough, and there are layered accumulations on the fiber surface, and a sticky coating is formed on the fiber surface.

[0045] The polydopamine modified continuous aramid fiber was dipped, and the excess resin was scraped off. The fiber was placed in the mold of the transverse filament composite material in the transverse direction. The unsaturated polyester resin was slowly injected into the mold to fill the mold and close the mold. After waiting for the resin to gel, the resin was placed in an oven for curing at 60°C for 12 hours. The interfacial bonding strength of the polydopamine modified continuous aramid fiber / unsaturated polyester resin transverse filament composite material is 29.12 MPa Figure 3 . The micro-morphology of the tensile fracture cross-section of the polydopamine modified continuous aramid fiber / unsaturated polyester resin transverse filament composite material is shown in Figure 4(B) shows that there is resin residue on the surface of continuous aramid fiber.

[0046] The polydopamine modified continuous aramid fiber was dipped and the excess resin was scraped off. The dipped fiber was stacked in the mold according to the collagen fiber interlayer arrangement mode of the biomimetic compact bone at 30°, and a contact pressure of about 10 MPa was applied at the beginning. After waiting for the resin to gel, it was placed in an oven for curing at 60°C for 12 hours. The tensile stress-strain and tensile strength of the polydopamine modified continuous aramid fiber / unsaturated polyester resin composite are shown in Figure 5 , and the tensile strength reaches 836.85 MPa. Figure 6 (B) is the scanning electron microscope picture of the tensile fracture section of the polydopamine modified continuous aramid fiber / unsaturated polyester resin composite.

[0047] Comparative Example 2: Preparation and performance characterization of a continuous aramid fiber / unsaturated polyester resin composite. Compared with Example 1, the continuous aramid fiber was not surface modified by polyethyleneimine-polydopamine. The specific content is as follows:

[0048] The aramid fiber was soaked in ethyl acetate for 24 hours for surface pretreatment to remove impurities on the fiber surface, and then dried. Figure 9 The scanning electron microscope picture of the continuous aramid fiber can be seen that there are fine grooves and micro-pits on the fiber surface. The continuous aramid fiber was dipped and the excess resin was scraped off, and was laid horizontally in the mold of the horizontal filament composite. The unsaturated polyester resin was slowly injected into the mold to fill it and the mold was closed. A contact pressure of about 10 MPa was applied at the beginning. After waiting for the resin to gel, it was placed in an oven for curing at 60°C for 12 hours. The interfacial bonding strength of the continuous aramid fiber / unsaturated polyester resin horizontal filament composite is 22.25 MPa Figure 3 , Figure 4 (C) is the scanning electron microscope picture of the tensile fracture section of the polydopamine modified continuous aramid fiber / unsaturated polyester resin horizontal filament composite. There is only a small amount of resin residue on the surface of the continuous aramid fiber.

[0049] The continuous aramid fiber was dipped and the excess resin was scraped off. The dipped fiber was stacked in the mold according to the collagen fiber interlayer arrangement mode of the biomimetic compact bone at 30°, and a contact pressure of about 10 MPa was applied at the beginning. After waiting for the resin to gel, it was placed in an oven for curing at 60°C for 12 hours. The tensile stress-strain and tensile strength of the continuous aramid fiber / unsaturated polyester resin composite are shown in Figure 5 , and the tensile strength reaches 714.71 MPa. Figure 6 (C) is the scanning electron microscope picture of the tensile fracture section of the continuous aramid fiber / unsaturated polyester resin composite. The fatigue life curve of the unmodified continuous aramid fiber / unsaturated polyester resin composite is shown in Figure 7As shown, the fatigue life gradually decreases with the increase of stress level, the fatigue life under 600 MPa is 160,000 times, the fatigue life under 500 MPa reaches 2,810,000 times, and the fatigue life under 400 MPa reaches 25,110,000 times.

[0050] Comparative analysis of the above embodiment 1 and comparative example 2, polyethyleneimine-polydopamine-continuous aramid fiber / unsaturated polyester resin (PEI-PDA-AF / UP) composite material and unmodified continuous aramid fiber / unsaturated polyester resin (AF / UP) composite performance related parameters are shown in table 1. The interfacial bonding strength of polyethyleneimine-polydopamine modified continuous aramid fiber / unsaturated polyester resin composite material reaches 40.60 MPa, which is increased by 82.47% compared with unmodified continuous aramid fiber composite material; The tensile strength reaches 959.07 MPa, which is increased by 34.19% compared with unmodified continuous aramid fiber composite material. The fatigue life under 600 MPa reaches 760,000 times, which is increased by 385% compared with unmodified continuous aramid fiber composite material (160,000 times); The fatigue life under 500 MPa reaches 10,470,000 times, which is increased by 273% compared with unmodified continuous aramid fiber composite material (2,810,000 times); The fatigue life under 400 MPa reaches 87,100,000 times, which is increased by 247% compared with unmodified continuous aramid fiber composite material (25,110,000 times).

[0051] Table 1 Performance comparison of polyethyleneimine-polydopamine modified continuous aramid fiber / unsaturated polyester resin (PEI-PDA-AF / UP) composite material and unmodified continuous aramid fiber / unsaturated polyester resin (AF / UP) composite material

[0052]

[0053] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a high-strength, fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material, characterized by: Using unsaturated polyester resin as the matrix and polyethyleneimine-polydopamine modified continuous aramid fiber as the reinforcement, polydopamine and polyethyleneimine are grafted onto the continuous aramid fiber by utilizing the Michael addition reaction and Schiff base reaction of polydopamine and polyethyleneimine. The modified continuous aramid fiber is then made to mimic the collagen fiber arrangement structure of compact bone to prepare a high-strength and fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material.

2. The preparation method according to claim 1, wherein: The steps include: (1) Surface modification of continuous aramid fibers: Continuous aramid fibers were pretreated by soaking in ethyl acetate for 24 hours to remove impurities on the fiber surface and then dried; A mixed solution of polydopamine and polyethyleneimine was prepared in a mass ratio of 1:1, tris(hydroxymethyl)aminomethane was added to adjust the pH to 8.5, and the mixture was stirred again to obtain a modified mixed solution; The pretreated continuous aramid fiber was immersed in the continuous aramid fiber, maintained at 37°C and 180 rpm for 24 hours, then taken out, impurities attached to the fiber surface were washed with deionized water, and the fiber was dried to obtain the polyethyleneimine-polydopamine modified continuous aramid fiber; (2) Dipping: Add methyl ethyl ketone peroxide (MEP) as an accelerator and cobalt cyclohexanecarboxylate (CO) as an initiator to unsaturated polyester resin as a glue solution. The mass ratio of unsaturated polyester resin, MEP and CO is 100:1:

2. The polyethyleneimine-polydopamine modified continuous aramid fibers are placed in a glue solution for dipping at room temperature, excess resin is scraped off, and the dipped polyethyleneimine-polydopamine modified continuous aramid fibers are arranged according to the interlayer arrangement structure of collagen fibers in compact bone and placed in a dry mold; (3) Curing: Apply a contact pressure of 10 MPa at the beginning of mold closing. After the unsaturated polyester resin turns into a gel state, place the mold in an oven and cure it at 60°C for 12 hours to obtain a high-strength, fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material.

3. The preparation method according to claim 2, wherein: The aramid fiber is para-aramid fiber, Kevlar 29, 1500 D.

4. The preparation method according to claim 2, wherein: When the mixed solution of polydopamine and polyethyleneimine described in step (1) is prepared, the concentration of the polydopamine solution is 2 mg / ml, the concentration of polyethyleneimine is 2 mg / ml, and the mass concentration ratio of the polydopamine to the polyethyleneimine is 1:

1.

5. The preparation method according to claim 2, wherein: The unsaturated polyester resin in step (2) is 191 type unsaturated polyester. When the resin is cured and formed, an accelerator is first added to the unsaturated polyester resin, mixed evenly, and then an initiator is added and stirred evenly. The continuous aramid fiber is impregnated with the resin before the resin reaches a gel state.

6. A high-strength, fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material prepared by the method according to any one of claims 1 to 5.

7. The high-strength, fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material according to claim 6, characterized in that: The continuous aramid fiber in the high-strength and fatigue-resistant continuous aramid fiber / unsaturated polyester resin composite material is oriented in a dense structure that mimics the dense collagen fiber. The interface bonding strength reaches 40.60 MPa, the tensile strength reaches 959.07 MPa, the fatigue life reaches 760,000 times at 600 MPa, the fatigue life reaches 10.47 million times at 500 MPa, and the fatigue life reaches 87.1 million times at 400 MPa.

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