CN114058323B - Interlayer toughening composite material and preparation method thereof - Google Patents

Abstract

The invention discloses an interlayer toughened composite material and a preparation method thereof. The composite material comprises a resin-carbon nanotube precoat layer formed by coating a carbon nanotube-acetone-resin mixture on an interlayer toughened surface, and The resin-aramid pulp-curing agent bonding layer is formed by coating the resin-carbon nanotube pre-coating layer with the aramid pulp-resin-curing agent mixture. The beneficial effects of the present invention: by grinding the interlayer toughened surface, holes or dents can be formed on the surface, the contact area between the interlayer toughened surface and the resin can be increased, and the carbon nanotubes and the resin flow into the holes or dents to achieve the toughening effect; the aramid pulp-resin-curing agent mixture is applied to the resin-carbon nanotube pre-coating, and the curing agent chemically reacts with the resin in the resin-carbon nanotube pre-coating , to improve the adhesive properties.

Description

A kind of interlayer toughened composite material and preparation method thereof

【Technical field】

The invention relates to the technical field of interlayer toughening, in particular to an interlayer toughening composite material and a preparation method thereof.

【Background technique】

With the increasing application of composite materials, the research requirements for their material properties are becoming more and more in-depth. Although the composite structure has the advantages of high specific stiffness and high specific strength, the brittle composite structure is prone to fine delamination during mechanical processing, and at the same time, it leads to failures such as fiber breakage. Many mechanical components have weak links in performance, which significantly reduces the mechanical properties of their structures, which poses a greater threat to the safety of structures.

In order to improve the performance of composite structures as a whole, the mechanical properties of composite thin-walled structures can be improved by introducing patch reinforcement, which is a simple and effective method. However, the introduction of patches is still limited by the weak adhesive interface. If the bonding interface is weak, the patch is prone to separation from the structure, preventing the patch from continuing to perform its reinforcing effect. Therefore, it is very necessary to propose an effective method of strengthening the bonding interface toughening from the perspective of bonding interface toughening, so as to improve the reinforcement effect of the patch on the thin-walled structure of the composite material.

[Content of the invention]

The invention discloses an interlayer toughened composite material and its preparation, which can solve the technical problems involved in the background technology.

For achieving the above object, the technical scheme of the present invention is:

A preparation method of an interlayer toughened composite material, the preparation method comprising the steps of:

S1. Prepare aramid pulp-resin-curing agent mixture, which specifically includes:

S11. Take a certain amount of aramid pulp and acetone, stir fully, and the stirring time is 10-30 minutes to form an aramid pulp-acetone mixture;

S12. Add resin to the aramid pulp-acetone mixture, stir fully, and the stirring time is 10-30 minutes to form the aramid pulp-acetone-resin mixture;

S13, when the acetone is completely volatilized to form an aramid pulp-resin mixture;

S14. Add a curing agent to the aramid pulp-resin mixture, and stir appropriately for 2-10 minutes to form an aramid pulp-resin-curing agent mixture;

S2, prepare carbon nanotube-acetone-resin mixture, which specifically includes:

S21, take a certain amount of carbon nanotubes and acetone, and stir appropriately for 2-10 minutes to form a carbon nanotube-acetone mixture;

S22, adding resin to the carbon nanotube-acetone mixture, and stirring appropriately to form a carbon nanotube-acetone-resin mixture;

S3 prepares the bonding interface, which includes:

S31, coating the carbon nanotube-acetone-resin mixture on the interlayer toughened surface to form a resin-carbon nanotube precoat layer;

S32, coating the aramid pulp-resin-curing agent mixture on the resin-carbon nanotube pre-coating layer to form an aramid pulp-resin-curing agent bonding layer.

As a preferred improvement of the present invention: in step S11, the mass ratio of the aramid pulp and acetone is at least 1:1.

As a preferred improvement of the present invention: in step S12, the mass ratio of acetone to epoxy resin is 4:1.

As a preferred improvement of the present invention: in step S13, the volatilization time is not less than 12 days.

As a preferred improvement of the present invention: in step S21, the mass ratio of the carbon nanotubes and acetone is at least 1:1.

As a preferred improvement of the present invention: in step S22, the mass ratio of the resin to the carbon nanotube-acetone mixture is 1:4.

As a preferred improvement of the present invention: in step S21, the modulus of the carbon nanotubes is 1TPa, and the tensile strength is 50-200GPa.

As a preferred improvement of the present invention: in steps S11 and S21, a mechanical stirrer is used to stir the aramid pulp and acetone, as well as the carbon nanotubes and acetone.

The present invention also provides an interlayer toughened composite material prepared by the method for preparing the interlayer toughened composite material, which comprises carbon nanotube-acetone-resin mixture coated on the interlayer toughened surface and formed The resin-carbon nanotube pre-coating and the resin-aramid pulp-curing agent adhesive layer formed by coating the resin-carbon nanotube pre-coating with the aramid pulp-resin-curing agent mixture.

As a preferred improvement of the present invention: before the carbon nanotube-acetone-resin mixture is coated on the interlayer toughened surface, the surface is polished to form holes or dents that increase the contact area between the surface and the resin.

The beneficial effects of the present invention are as follows:

(1) The interlayer toughened composite material prepared by the present invention can significantly improve the resistance to bending load, and at the same time can effectively solve the problem of bonding between the reinforced patch and the original structure, improve the problem of patch falling off caused by traditional bonding, and greatly improve the Overall performance of structures with defects;

(2) By grinding the interlayer toughened surface, holes or dents can be formed on the surface, which can increase the contact area between the interlayer toughened surface and the resin, and the carbon nanotubes and resin flow into the holes or dents to achieve Toughening effect;

(3) The aramid pulp-resin-curing agent mixture is used to coat the resin-carbon nanotube pre-coating, and the curing agent chemically reacts with the resin in the resin-carbon nanotube pre-coating, improving the viscosity connection performance.

【Description of drawings】

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, under the premise of no creative work, other drawings can also be obtained from these drawings, wherein:

1 is a schematic structural diagram of a toughened structure provided by the present invention;

2 is a schematic structural diagram of a toughened structure having a resin-curing agent bonding interface of the present invention;

3 is a schematic structural diagram of a toughened structure having a resin-carbon nanotube-curing agent bonding interface according to the present invention;

4 is a schematic structural diagram of a toughened structure having a resin-aramid pulp-curing agent bonding interface according to the present invention;

5 is a schematic structural diagram of a toughened structure with an interlayer toughened composite material according to the present invention;

6 is a schematic diagram of the test structure of the toughened structure by the Instron 5982 universal testing machine of the present invention;

Fig. 7 is a bending load-displacement curve comparison diagram of the present invention;

Fig. 8 is the bending failure process diagram of the present invention;

Fig. 9 is a bending load-displacement curve comparison diagram of the effect of different bonding patches of the present invention on the bending performance of an open-cell CFRP thin-walled structure;

Fig. 10 is a bending load-displacement curve comparison diagram corresponding to all situations of the present invention;

Figure 11 is a comparison diagram of the maximum bending load corresponding to all situations of the present invention;

In the figure, 1. The thin-walled structure to be reinforced; 2. The patch structure; 3. The bonding interface; 4. The resin-curing agent bonding interface; 5. The resin-carbon nanotube-curing agent bonding interface; 6. The first Resin-aramid pulp-curing agent bonding interface; 7. Interlayer toughening composite material; 71. Resin-carbon nanotube precoating; 72. Second resin-aramid pulp-curing agent bonding interface.

【Detailed ways】

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relationship between various components under a certain posture (as shown in the accompanying drawings). The relative positional relationship, the movement situation, etc., if the specific posture changes, the directional indication also changes accordingly.

In addition, descriptions such as "first", "second", etc. in the present invention are only for descriptive purposes, and should not be construed as indicating or implying their relative importance or implicitly indicating the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, the terms "connected", "fixed" and the like should be understood in a broad sense, for example, "fixed" may be a fixed connection, a detachable connection, or an integrated; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be an internal communication between two elements or an interaction relationship between the two elements, unless otherwise explicitly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

The invention provides a preparation method of an interlayer toughened composite material. The preparation method comprises the following steps:

S1, prepare aramid pulp-resin-curing agent mixture;

S11. Take a certain amount of aramid pulp and acetone, stir fully, and the stirring time is 10-30 minutes to form an aramid pulp-acetone mixture;

Specifically, in the mixture of aramid pulp and acetone: the more acetone content, the more favorable the aramid pulp is evenly dispersed in the epoxy resin. In terms of mass percentage, the mass ratio of the aramid pulp and acetone is at least 1:1.

S12. Add resin to the aramid pulp-acetone mixture, stir fully, and the stirring time is 10-30 minutes to form the aramid pulp-acetone-resin mixture;

Specifically, the mass ratio of acetone to epoxy resin is 4:1.

S13, after the acetone is completely volatilized, the aramid pulp-resin mixture is formed;

Specifically, the volatilization time is not less than 12 days.

S14. Add a curing agent to the aramid pulp-resin mixture, and stir appropriately for 2-10 minutes to form an aramid pulp-resin-curing agent mixture;

Specifically, the mass ratio of the curing agent to the aramid pulp-resin mixture is 1:5.

It should be further explained that due to the volatilization of toxic liquids, the entire indoor operation needs to be carried out in the environment of a fume hood. First, in order to evenly disperse the aramid pulp in the epoxy resin, the aramid pulp is dipped in an acetone solution and mixed. Then, the aramid pulp and acetone were thoroughly stirred with a mechanical mixer at a maximum rotation speed of 11500 rpm to obtain a homogeneous aramid pulp-acetone mixture. Based on a certain ratio (80 vol. % of acetone and 20 vol. % of epoxy resin are used in the present invention), the epoxy resin without curing agent and acetone are mixed together. The aramid pulp-acetone-epoxy was again mixed with a mechanical mixer. Then, the uniform aramid pulp-acetone-epoxy resin mixture is placed in an oven at a certain temperature to accelerate the full volatilization of acetone. The purpose of volatilizing acetone is to reduce the effect of acetone on the curing of epoxy resin. After the acetone has completely evaporated, the remaining mixture solution contains only epoxy resin and uniformly distributed aramid pulp. Finally, add the curing agent to the aramid pulp-epoxy resin mixture in a certain proportion, and then stir properly with a small wooden stick to make the curing agent as evenly distributed in the mixture as possible to form the aramid pulp-epoxy resin-curing agent mixture.

S2, prepare carbon nanotube-acetone-resin mixture, which specifically includes:

S21, take a certain amount of carbon nanotubes and acetone, and stir appropriately to form a carbon nanotube-acetone mixture;

The higher the acetone content, the more favorable the carbon nanotubes are uniformly dispersed in the epoxy resin, and the mass ratio of the carbon nanotubes and acetone is at least 1:1.

Specifically, the mass ratio of the carbon nanotube micro-nano to the acetone is: The carbon nanotube modulus is 1TPa, and the tensile strength is 50-200GPa

S22, adding resin to the carbon nanotube-acetone mixture, and stirring appropriately for 2-10 minutes to form a carbon nanotube-acetone-resin mixture;

Specifically, the mass ratio of acetone to epoxy resin is 4:1.

S3 prepares the bonding interface, which includes:

S31, coating the carbon nanotube-acetone-resin mixture on the interlayer toughened surface to form a resin-carbon nanotube precoat layer;

S32, coating the aramid pulp-resin-curing agent mixture on the resin-carbon nanotube pre-coating layer to form an aramid pulp-resin-curing agent bonding layer.

It should be further noted that, in a specific embodiment of the present invention, the resin is an epoxy resin. When preparing the carbon nanotube-acetone-resin mixture, the epoxy resin has high viscosity and weak fluidity. The main purpose of surface treatment with resin pre-coating is to reduce the viscosity of epoxy resin (increase fluidity), so that the epoxy resin can easily flow into the micro-dents and micro-holes of the toughened surface and increase the contact area. To achieve this, a large amount of acetone can be added to a small amount of epoxy resin with no added curing agent, which also thins and wets the resin. Since the size of carbon nanotubes is very small and smaller than the size of micro-dimples and micro-holes on the surface of the structure, a small amount of carbon nanotubes can be added to the mixed solution of resin and acetone. The carbon nanotubes flow into the micro-dimples and micro-holes together with the diluted resin to achieve the toughening effect of the resin. This carbon nanotube resin pre-coating surface treatment technology has higher bonding performance to the two structures than the resin pre-coating surface treatment. Before implementing the carbon nanotube resin pre-coating surface treatment technology, sandpaper can be used to polish the surface of the thin-walled structure and patch structure to be reinforced, so that more voids or dents are generated on the surface and the contact area between the surface and the resin is increased. The sanded structural surface is then cleaned with an acetone solution to remove any fine grime, such as dust and oil, that remains on the surface. Then, the thin-walled structure and patch structure to be reinforced are immersed in a resin-acetone mixed solution without adding a curing agent. After a few minutes, the thin-walled structure and patch structure to be reinforced were removed and set aside to wait for the acetone to evaporate completely. At this time, a layer of acetone-free and very thin resin-carbon nanotube precoat layer will remain on the surface of the thin-walled structure and patch structure to be reinforced.

The present invention also provides an interlayer toughened composite material prepared by the method for preparing the interlayer toughened composite material, comprising a resin formed by coating the carbon nanotube-acetone-resin mixture on the interlayer toughened surface -Carbon nanotube pre-coating and resin-aramid pulp-curing agent adhesive layer formed by coating the resin-carbon nanotube pre-coating with the mixture of aramid pulp-resin-curing agent. It should be noted that the interlayer toughened surface includes the above-mentioned surfaces of the thin-walled structure and patch structure to be reinforced.

It should be further noted that, before the carbon nanotube-acetone-resin mixture is coated on the interlayer toughened surface, the surface is polished to form holes or dents that increase the contact area between the surface and the resin.

Due to the diffusing effect of the curing agent in the resin, the resin in the resin-carbon nanotube precoat layer remaining on the surface of the thin-walled structure and patch structure to be reinforced will react with the diffusing curing agent. A certain pressure ensures the thinness of the interface, and it takes two weeks to complete the curing.

The interlayer toughened composite material provided by the present invention and the preparation method thereof will be described in detail below with specific examples.

As shown in FIG. 1 , a toughened structure includes a thin-walled structure 1 to be reinforced, a patch structure 2 , and a bonding interface 3 sandwiched between the thin-walled structure 1 to be reinforced and the patch structure 2 . 2 to 5 again, the toughened structure shown in FIG. 2 includes a thin-walled structure 1 to be reinforced, a patch structure 2 and a resin-curing agent bonding interface 4; the toughened structure shown in FIG. 3 includes Thin-walled structure 1, patch structure 2 and resin-carbon nanotube-curing agent bonding interface 5 to be reinforced; the toughened structure shown in Figure 4 includes thin-walled structure 1 to be reinforced, patch structure 2 and resin-aramid pulp - Curing agent bonding interface 6; the toughened structure shown in FIG. 5 includes a thin-walled structure 1 to be reinforced, a patch structure 2 and an interlayer toughened composite material 7. Specifically, the interlayer toughened composite material 7 includes a coating The resin-carbon nanotube precoat layer 71 covering the thin-walled structure 1 to be reinforced and the patch structure 2 is bonded with the second resin + aramid pulp + curing agent disposed between the two layers interface 72.

It should be noted that the toughened structures shown in FIGS. 2 to 4 are used as comparative examples of the toughened structures shown in FIG. 5 to which the toughened composite material provided by the present invention is applied. And, as shown in FIG. 2, there is no reinforcing additive in the resin-curing agent bonding interface 3, which serves as a control group. In Figure 3 and Figure 4, a small amount of carbon nanotubes and aramid pulp micro-nano were added to the bonding interface respectively, which played the role of resin toughening, but the interfacial adhesion between the resin and the composite material could not be improved. Therefore, the present invention proposes a bonding interface using the interlayer toughening material 6 of the present invention as shown in FIG. 5, which is based on the bonding interface 72 of the second resin + aramid pulp + curing agent. Carbon nanotube resin pre-coating surface treatment technology, that is, pre-coating a layer of resin-carbon nanotube pre-coating 71 on the surface of the toughened structure, so as to improve the contact area between the resin and the surface of the composite material and the toughness of the pre-coating resin.

The three-point bending test was carried out on the above four toughened structures through the Instron 5982 universal testing machine to evaluate their structural mechanical properties. As shown in Fig. 6, the experimental test was carried out at a certain loading speed, and the loading was stopped after the fracture of the toughened structure.

Figures 7 and 8 investigate the reinforcement effect of bonded patches (ie, patch structures) on open-cell composite thin-walled structures (ie, thin-walled structures to be reinforced). By comparing the patch-free reinforced intact plate with the perforated plate, it is shown that the introduction of mechanical openings can greatly reduce the bending stiffness and strength of the structure, in which the reduction of the highest bending load is as high as 49.26%. When the perforated plate is introduced into the patch, the initial stiffness of the structure is significantly increased, even much higher than that of the intact plate; however, the maximum bending load of the structure is still reduced by 14.48%. Although the perforated plate/opened patch with the pure resin interface showed a small decrease in the highest load, it was much higher than that of the perforated plate without patch reinforcement. This also shows that the introduction of the adhesive patch has a significant strengthening effect on the perforated plate, and can improve the initial failure strength of the thin-walled structure of the perforated composite material. Therefore, an in-depth analysis of the mechanical behavior of perforated plates reinforced with patches will be carried out. Through the analysis, it can be concluded that as long as the bending load does not reach the bending load corresponding to the initial degumming and the bending load corresponding to the complete degumming of the interface, the overall structure can continue to bear, which is the first layer of protection for the thin-walled structure of the open-cell composite; and The bending deformation resistance of the open cell structure itself is the second layer of protection. Therefore, the bonding ability of the bonding interface should be improved as much as possible, and the debonding of the interface should be delayed, so that the patch can play a longer role.

The reinforcing effect of the bonding patch structure on the thin-walled structure of the open-cell composite material to be reinforced is mainly reflected in the first half of the bending stage. Therefore, the influence of different bonding patches on the bending performance of the open-cell CFRP thin-walled structure was studied, as shown in Figure 9. . The bending stiffnesses corresponding to the carbon nanotube interface and the aramid pulp-tape interface are similar to those of the pure resin interface, but the maximum bending load is significantly higher. This is because the introduction of additives increases the toughness of the resin and improves the interfacial bonding properties, which in turn increases the time for the patch to provide bending resistance. Compared with the carbon nanotube interface, the highest bending load corresponding to the aramid pulp interface is higher, which is mainly due to the more effective fiber bridging of the multi-layered aramid pulp interface, and the size factor makes the interface relative to the carbon nanotube interface. thicker. By observing the corresponding bending behavior of the aramid pulp-RPC carbon nanotube interface, it can be found that the aramid pulp-RPC carbon nanotube interface not only exhibits the highest structural stiffness, but also has the highest bending load. This shows that the surface treatment of RPC carbon nanotubes can effectively improve the adhesion between the resin and the surface of the thin-walled structure. The surface treatment of RPC carbon nanotubes combined with the interfacial toughening of the aramid pulp and basil plays the role of a patch as much as possible.

Figures 10 and 11 compare the bending load-displacement curves and the maximum bending load for all cases. As shown in Figure 10, the additional bending load provided by the shaded area for the adhesive patch also means that more energy absorption is provided, compensating for the energy absorption reduced by the mechanical opening. In terms of maximum bending load (as shown in Figure 11), the maximum bending load corresponding to the pure resin interface is 68.55% higher than the maximum bending load corresponding to the perforated plate without patch reinforcement, but 14.48% lower than the maximum bending load corresponding to the intact plate %. When carbon nanotubes are used to toughen the bonding interface, the maximum bending load of the perforated plate can be increased by 103.65%, and it is also 3.34% higher than the corresponding maximum bending load of the complete plate. However, the maximum bending load corresponding to the aramid pulp-tape interface is increased by 177.89%, and it is also 41.00% higher than the maximum bending load corresponding to the intact plate. Most obviously, the aramid pulp-RPC carbon nanotube interface exhibits the highest structural reinforcement properties, with an improved maximum bending load of 207.21%, which is 55.88% higher than that of the intact plate. Through the above comparison, it is revealed that the patch reinforcement can compensate for the performance reduction caused by the opening when combined with the advanced bonding interface toughening technology, and even make the residual bending resistance of the opening thin-wall structure much higher than that of the complete plate. Bending resistance properties. In the design of the bonding interface, the performance of the bonding interface should be improved as much as possible, otherwise the mechanical properties of the open-hole thin-walled structure will be reduced to the unreinforced situation after the patch is debonded, as shown in Figure 10.

The carbon nanotube aramid pulp provided by the invention is toughened between layers, effectively solves the problem of bonding between the reinforced patch and the original structure, improves the problem of patch falling off caused by traditional bonding, and greatly improves the overall performance of the structure with defects.

The beneficial effects of the present invention are as follows:

(1) The interlayer toughened composite material prepared by the present invention can significantly improve the resistance to bending load, and at the same time can effectively solve the problem of bonding between the reinforced patch and the original structure, improve the problem of patch falling off caused by traditional bonding, and greatly improve the Overall performance of structures with defects;

(2) By grinding the interlayer toughened surface, holes or dents can be formed on the surface, which can increase the contact area between the interlayer toughened surface and the resin, and the carbon nanotubes and resin flow into the holes or dents to achieve Toughening effect;

(3) The aramid pulp-resin-curing agent mixture is used to coat the resin-carbon nanotube pre-coating, and the curing agent chemically reacts with the resin in the resin-carbon nanotube pre-coating, improving the viscosity connection performance.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the application listed in the description and the embodiment, and it can be applied to various fields suitable for the present invention. For those skilled in the art, it can be easily Additional modifications are implemented, therefore, the invention is not limited to the specific details and illustrations shown and described herein without departing from the general concept defined by the appended claims and the scope of equivalents.

Claims (9)

1. A preparation method of an interlayer toughening composite material is characterized by comprising the following steps: the preparation method comprises the following steps:

s1, preparing an aramid pulp meal-resin-curing agent mixture, which specifically comprises:

s11, taking a certain amount of aramid pulp and acetone, and fully stirring for 10-30 minutes to form an aramid pulp-acetone mixture;

s12, adding resin into the aramid pulp-acetone mixture, and fully stirring for 10-30 minutes to form the aramid pulp-acetone-resin mixture, wherein the resin is epoxy resin;

s13, after acetone is completely volatilized, forming an aramid pulp dreg-resin mixture;

s14, adding a curing agent into the aramid pulp meal-resin mixture, and properly stirring for 2-10 minutes to form the aramid pulp meal-resin-curing agent mixture;

s2, preparing a carbon nano tube-acetone-resin mixture, which specifically comprises the following steps:

s21, taking a certain amount of carbon nano tube and acetone, and properly stirring for 2-10 minutes to form a carbon nano tube-acetone mixture;

s22, adding resin into the carbon nanotube-acetone mixture, and stirring the mixture properly to form a carbon nanotube-acetone-resin mixture, wherein the resin is epoxy resin;

s3 preparing a bonding interface, specifically comprising:

s31, coating the carbon nanotube-acetone-resin mixture on the interlayer toughening surface to form a resin-carbon nanotube precoating, and polishing the interlayer toughening surface before coating the carbon nanotube-acetone-resin mixture to form holes or dents for increasing the contact area between the surface and the resin;

and S32, coating the aramid pulp dreg-resin-curing agent mixture on the resin-carbon nano tube precoating layer to form an aramid pulp dreg-resin-curing agent adhesive layer.

2. The method of claim 1, wherein the method comprises the steps of: in step S11, the mass ratio of the aramid pulp to the acetone is at least 1: 1.

3. the method of claim 2, wherein the method comprises the steps of: in step S12, the mass ratio of acetone to epoxy resin is 4: 1.

4. a method of preparing an interlaminar toughened composite material as claimed in claim 1 or 3, wherein: in step S13, the volatilization time is not less than 12 days.

5. The method of claim 1, wherein the method comprises the steps of: in step S21, the mass ratio of the carbon nanotubes to acetone is at least 1: 1.

6. the method of claim 5, wherein the method comprises the steps of: in step S22, the mass ratio of acetone to epoxy resin is 4: 1.

7. the method of claim 6, wherein the method comprises the steps of: in step S21, the modulus of the carbon nanotube is 1TPa, and the tensile strength is 50-200 GPa.

8. The method of claim 1, wherein the method comprises the steps of: in steps S11 and S21, aramid pulp and acetone and carbon nanotubes and acetone are stirred by a mechanical stirrer.

9. An interlayer toughened composite material prepared by the method of preparing an interlayer toughened composite material according to any one of claims 1 to 8, wherein: the adhesive comprises a resin-carbon nano tube precoat formed by coating a carbon nano tube-acetone-resin mixture on an interlayer toughening surface and a resin-aramid pulp meal-curing agent adhesive layer formed by coating an aramid pulp meal-resin-curing agent mixture on the resin-carbon nano tube precoat.

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