CN104558659A - Preparation of carbon fiber/epoxy resin prepreg sprayed with aminated carbon nanotubes - Google Patents

Abstract

The invention belongs to the field of composite material preparation, in particular to a preparation method of carbon nanotube electrostatic spraying carbon fiber prepreg. It is characterized in that the amino-grafted carbon nanotubes are quickly sprayed onto the surface of the carbon fiber/epoxy resin prepreg by electrostatic spraying technology, which can significantly improve the compressive strength, modulus and interlayer shear strength of the carbon fiber composite material. The present invention includes the following technical steps. Step Ⅰ: Grinding amino-grafted carbon nanotubes and a preferred electrostatic spray solvent in a ball mill according to a certain ratio to obtain a uniform and stable suspension; Step Ⅱ: Put the suspension obtained in step Ⅰ into an electrostatic spray device, and put The carbon nanotubes are evenly sprayed onto the surface of the carbon fiber/epoxy resin prepreg; step III: the thickness of the carbon nanotube coating on the surface of the carbon fiber prepreg is controlled at 10-80 μm. In the invention, the content of the carbon nanotubes between the layers of the composite material is controllable, does not affect the processing technology of the composite material, is easy to operate, and is easy to popularize and apply in actual production.

Description

A kind of aminated carbon nanotube spraying carbon fiber / Preparation of epoxy resin prepreg

technical field

The invention belongs to the field of preparation of carbon fiber composite materials, in particular to a preparation method of amino-grafted carbon nanotube electrostatically sprayed carbon fiber/epoxy resin unidirectional prepreg or fabric prepreg.

Background technique

Carbon fiber/epoxy resin composites have a series of excellent properties such as high strength, high modulus, low density, and dimensional stability, and have been widely used in aerospace, energy transportation, sports equipment, and military industries. However, the current carbon fiber/epoxy resin composites still have problems such as easy delamination between layers, poor impact resistance, and low mechanical properties perpendicular to the fiber direction, which make it difficult to meet the application requirements of some advanced composite materials. These properties are mainly affected by the interface properties between the resin matrix and carbon fibers. Improving the interface properties of resin matrix composites can effectively improve the comprehensive properties of composites.

Carbon nanotubes have excellent mechanical properties, high aspect ratio and other advantages, and can be used as reinforcements to improve the performance of composite materials. However, due to the high specific surface energy of carbon nanotubes, agglomeration is very easy to occur, which affects their dispersion in composite materials, restricts their application, and makes it difficult to exert their due reinforcing effect. The carbon nanotubes are functionalized to introduce different functional groups on the surface, which can effectively reduce the agglomeration of carbon nanotubes. The published patents US8187703 B2 and CN102140230 A use mechanical stirring to blend functionalized carbon nanotubes with epoxy resin to improve the performance of composite materials by strengthening the resin matrix. The effect of material interfacial properties is not obvious. Although there have been reports on the use of thermoplastic polymer fibers containing carbon nanotubes to reinforce and toughen carbon fiber composites, for example, the disclosed patent CN102794952 A uses the fiber film containing oriented carbon nanotubes prepared by electrospinning to strengthen and toughen Carbon fiber composites can improve the bending strength, modulus and interlaminar fracture toughness of composite materials. However, the preparation process of polymer fibers is relatively complicated, and the amount of carbon nanotubes added is limited, making it difficult to achieve large-scale applications. However, growing carbon nanotubes directly on the surface of carbon fibers to improve their interfacial properties cannot be applied industrially due to high preparation costs and low yields. In recent years, electrospinning and electrostatic spraying technologies have been continuously developed. By controlling the process parameters, various nanofibers and nanoparticles can be prepared efficiently and conveniently.

Therefore, this patent uses electrostatic spraying technology to quickly and evenly spray amino-grafted carbon nanotubes on the surface of carbon fiber/epoxy resin prepregs, and the prepregs sprayed by carbon nanotubes can be used to prepare various carbon fiber composite materials products. Compared with the existing carbon nanotube reinforced carbon fiber composite material method, the present invention can significantly improve the compressive strength and modulus of the carbon fiber composite material, as well as the interlaminar shear strength, without affecting the processing technology of the composite material, and the carbon nanotubes in the composite material The content between layers is controllable, and the technology is easy to operate and easy to popularize and apply in actual production.

Contents of the invention

The purpose of the present invention is to provide a carbon nanotube electrostatic spraying method for carbon fiber unidirectional prepreg or fabric prepreg, the specific technical content is as follows.

A preparation method of amino-grafted carbon nanotube electrostatic spraying carbon fiber/epoxy resin prepreg is characterized in that it comprises the following components and steps:

Component 1: carbon nanotubes with amino groups grafted on the surface, the amino compound grafted on the surface of carbon nanotubes is one of ethylenediamine, 2,4-diethyl-toluenediamine, isophoronediamine or Several kinds, the grafting rate of amino compound on the surface of carbon nanotubes is 1.0~2.5wt%. Aminated multi-walled carbon nanotubes can be obtained from carboxylated multi-walled carbon nanotubes through acid chlorination and amination chemical treatment, and this process belongs to the well-known mature technology in the field.

Component 2: Preferred electrostatic spray organic solvents include N,N-dimethylformamide and tetrahydrofuran.

Component 3: carbon nanotube/epoxy resin prepreg, including carbon fiber unidirectional prepreg and fabric prepreg.

Step 1: adding the carbon nanotubes grafted with amino groups on the surface into the preferred organic solvent for electrostatic spraying, ultrasonically oscillating evenly, and the mixing amount of the carbon nanotubes in the preferred organic solvent for electrostatic spraying is 3-20wt%. Put the ultrasonically oscillated liquid mixture into a planetary ball mill and mill for 1 to 3 hours to obtain a uniform black suspension. After ball milling, the aspect ratio of the carbon nanotubes is controlled between 50 and 300. Leave it for 1 day without delamination;

Step Ⅱ: Put the suspension of carbon nanotubes obtained in step Ⅰ into the syringe of the electrostatic spraying device. The nozzle of the syringe is connected to the positive electrode of the high-voltage electric field, and the commercial carbon fiber/epoxy resin prepreg cut into a certain size is used as the electrostatic spraying device Push the syringe to spray the amino-grafted carbon nanotubes evenly onto the surface of the carbon fiber prepreg.

Step Ⅲ: Control the electrostatic spraying time to 30-120 minutes to obtain carbon fiber/epoxy resin prepregs with different contents of amino-grafted carbon nanotubes sprayed on the surface, and the thickness of the carbon nanotube coating layer is 10-80 μm

After electrostatic spraying of amino-grafted carbon nanotubes, the compressive strength, modulus, and interlayer shear strength of carbon fiber composites can be significantly improved, and the interface properties can be improved. In the epoxy resin cross-linked network, it plays a reinforcing role, and improves the toughness of the epoxy resin by adjusting the cross-linked network density. At the same time, the addition of carbon nanotubes does not affect the processing technology of the composite material, and the content of carbon nanotubes between layers of the composite material is controllable. This technology is easy to operate and easy to popularize and apply in actual production.

The following invention effects can be obtained through the above technical content: after the carbon fiber/epoxy resin prepreg is sprayed on the surface of carbon nanotubes grafted with amino groups, it is pressed into a carbon fiber composite laminate, and the compressive strength, modulus and interlaminar shear strength All have been significantly improved, among which the interlaminar shear strength has increased by ≥10%, and the 90° compressive strength and modulus of the unidirectional composite plate have increased by ≥10%.

Detailed ways:

The present invention is illustrated in detail by the following examples.

In each embodiment, the compressive strength and modulus of the carbon fiber composite laminate are tested according to GB/T 1448-2005, and the interlaminar shear strength of the carbon fiber composite laminate is tested according to JC/T 773-96.

Example 1:

Component 1 is multi-walled carbon nanotubes grafted on the surface of ethylenediamine, which is obtained by TNMC3 carboxylated multi-walled carbon nanotubes produced by Chengdu Zhongke Times Nano Co., Ltd. through acyl chloride and amination treatment. The surface grafting ratio of amino groups is 2.5wt%, the outer diameter of carbon nanotubes is 10~30nm, and the average length is 1μm; component 2 is N,N-dimethylformamide, with a purity of ≥99%, produced by Yangzhou Yaguan Chemical Co., Ltd.; component 3 is Self-made unidirectional prepreg of Toray ^® T700-12K carbon fiber/4,4′diaminodiphenylmethane tetraglycidylamine epoxy resin, containing 4,4′diaminodiphenylsulfone as curing agent, prepreg The material thickness is 0.15 mm, and the surface density is 220 g/m ² . Step 1: Add multi-walled carbon nanotubes grafted on the surface of ethylenediamine into N,N-dimethylformamide, the mixing amount of carbon nanotubes is 3 wt%, and ultrasonically oscillate for 1 hour to form a uniform mixed solution. Put the ultrasonically oscillated mixture into a planetary ball mill and mill for 1 hour to obtain a uniform black suspension with an average aspect ratio of carbon nanotubes of 300; Step II: The carbon nanotube suspension obtained in Step I Placed in the syringe of the electrostatic spraying device, the syringe nozzle is connected to the positive electrode of the high-voltage electric field, and the carbon fiber prepreg cut into a certain size is used as the negative electrode receiver of the electrostatic spraying device, and the injector is pushed to uniformly spray the carbon nanotubes grafted with amino groups on the surface to the carbon fiber prepreg surface. The voltage of the high-voltage electric field of the spraying device is 18kV, and the receiving distance is 250mm; step III: the electrostatic spraying time is set to 30 minutes, and the thickness of the carbon nanotube coating layer obtained is 10 μm.

The prepreg is pressed into a unidirectional composite laminate with a thickness of 2mm by molding method, the pressure of the hot press is 10MPa, and the fiber volume content is 65%. When carbon nanotubes are not sprayed on the surface of the prepreg, the 0° compressive strength and modulus of the T700 carbon fiber composite unidirectional plate are 1450MPa and 150GPa, and the 90° compressive strength and modulus are 225MPa and 11.5GPa, respectively. The shear strength is 91.5MPa. After spraying amino-grafted carbon nanotubes on the surface of the prepreg, the 0° compressive strength and modulus of the T700 carbon fiber composite unidirectional plate are 1530MPa and 156GPa, and the 90° compressive strength and modulus are 251MPa and 12.8GPa, respectively. The interlaminar shear strength is 100.8 MPa.

Example 2:

Component 1 is multi-walled carbon nanotubes grafted on the surface of ethylenediamine, which is obtained by TNMC3 carboxylated multi-walled carbon nanotubes produced by Chengdu Zhongke Times Nano Co., Ltd. through acyl chloride and amination treatment. The surface grafting ratio of amino groups is 2.1wt%, the outer diameter of carbon nanotubes is 10~30nm, and the average length is 1μm; component 2 is tetrahydrofuran, purity ≥ 99%, produced by Shanghai Nanze Chemical Co., Ltd.; component 3 is self-made Toray ^® T700-12K carbon fiber/ Unidirectional prepreg of 4,4′ diaminodiphenylmethane tetraglycidylamine epoxy resin, the curing agent is 4,4′ diaminodiphenyl sulfone, the thickness is 0.15mm, and the surface density is 220g/m ² . Step I: adding multi-walled carbon nanotubes grafted on the surface of ethylenediamine into tetrahydrofuran, the mixing amount of carbon nanotubes is 10wt%, and ultrasonically oscillating for 1 hour to form a uniform mixed solution. Put the ultrasonically oscillated mixture into a planetary ball mill and mill for 2 hours to obtain a uniform black suspension with an average aspect ratio of carbon nanotubes of 120; step II: suspend the carbon nanotubes obtained in step I The liquid is placed in the syringe of the electrostatic spraying device, and the injector nozzle is connected to the positive electrode of the high-voltage electric field. The carbon fiber prepreg cut into a certain size is used as the negative electrode receiver of the electrostatic spraying device, and the injector is pushed to uniformly graft the carbon nanotubes with amino groups on the surface. Spray onto the surface of carbon fiber prepreg. The voltage of the high-voltage electric field of the spraying device is 18kV, and the receiving distance is 250mm; step III: the electrostatic spraying time is set to 60 minutes, and the thickness of the carbon nanotube coating layer obtained is 30 μm.

The prepreg is pressed into a unidirectional composite laminate with a thickness of 2mm by molding method, the pressure of the hot press is 10MPa, and the fiber volume content is 65%. When carbon nanotubes are not sprayed on the surface of the prepreg, the 0° compressive strength and modulus of the T700 carbon fiber composite unidirectional plate are 1450MPa and 150GPa, and the 90° compressive strength and modulus are 225MPa and 11.5GPa, respectively. The shear strength is 91.5MPa. After spraying amino-grafted carbon nanotubes on the surface of the prepreg, the 0° compressive strength and modulus of the T700 carbon fiber composite unidirectional plate were 1515MPa and 158GPa, and the 90° compressive strength and modulus were 248MPa and 13.2GPa, respectively. The interlaminar shear strength is 102 MPa.

Example 3

Component 1 is multi-walled carbon nanotubes grafted on the surface of ethylenediamine, which is obtained by TNMC3 carboxylated multi-walled carbon nanotubes produced by Chengdu Zhongke Times Nano Co., Ltd. through acyl chloride and amination treatment. The surface grafting ratio of amino groups is 1.5wt%, the outer diameter of carbon nanotubes is 10~30nm, and the average length is 1μm; component 2 is N,N-dimethylformamide, with a purity of ≥99%, produced by Yangzhou Yaguan Chemical Co., Ltd.; component 3 is Homemade Toray ^® T700-12K carbon fiber / 4,4′ diaminodiphenylmethane tetraglycidylamine epoxy resin plain weave prepreg containing 4,4′ diaminodiphenyl sulfone curing agent, thickness 0.15mm, surface density is 350g/m ² . Step I: Add multi-walled carbon nanotubes grafted on the surface of ethylenediamine into N,N-dimethylformamide, the mixing amount of carbon nanotubes is 20wt%, and ultrasonically oscillate for 1 hour to form a uniform mixed solution. Put the ultrasonically oscillated mixture into a planetary ball mill and mill for 3 hours to obtain a uniform black suspension with an average aspect ratio of carbon nanotubes of 50; Step II: the carbon nanotube suspension obtained in Step I Placed in the syringe of the electrostatic spraying device, the syringe nozzle is connected to the positive electrode of the high-voltage electric field, and the carbon fiber prepreg cut into a certain size is used as the negative electrode receiver of the electrostatic spraying device, and the injector is pushed to uniformly spray the carbon nanotubes grafted with amino groups on the surface to the carbon fiber prepreg surface. The voltage of the high-voltage electric field of the spraying device is 18kV, and the receiving distance is 250mm; step III: the electrostatic spraying time is set to 120min, and the thickness of the carbon nanotube coating layer obtained is 80μm.

The prepreg was pressed into a plain weave laminate with a thickness of 2mm by molding method, the pressure of the hot press was 10MPa, and the fiber volume content was 63%. When carbon nanotubes are not sprayed on the surface of the prepreg, the 90° compressive strength and modulus of the T700 carbon fiber composite plate are 370MPa and 48.2GPa, respectively, and the interlaminar shear strength is 55.2MPa. After spraying amino-grafted carbon nanotubes on the surface of the prepreg, the 90° compressive strength and modulus of the T700 carbon fiber composite plate were 424MPa and 53.5GPa, respectively, and the interlaminar shear strength was 60.8MPa.

Example 4

Component 1 is multi-walled carbon nanotubes grafted on the surface of 2,4-diethyl-toluenediamine, which is obtained by TNMC3 carboxylated multi-walled carbon nanotubes produced by Chengdu Zhongke Times Nano Co., Ltd. through acid chloride and amination treatment , the surface grafting rate of amino groups is 1.8wt%, the outer diameter of carbon nanotubes is 10-30nm, and the average length is 1μm; component 2 is tetrahydrofuran, with a purity of ≥99%, produced by Shanghai Nanze Chemical Co., Ltd.; component 3 is self-made Unidirectional prepreg of Toray ^® T700-12K carbon fiber / 4,4′ diaminodiphenylmethane tetraglycidylamine epoxy resin, containing 4,4′ diaminodiphenyl sulfone as curing agent, thickness of 0.15 mm, and the surface density is 220g/m ² . Step I: adding multi-walled carbon nanotubes grafted on the surface of 2,4-diethyl-toluenediamine into tetrahydrofuran, the mixing amount of carbon nanotubes is 3wt%, and ultrasonically oscillating for 1 hour to form a uniform mixed solution. Put the ultrasonically oscillated mixture into a planetary ball mill and mill for 1 hour to obtain a uniform black suspension with an average aspect ratio of carbon nanotubes of 300; Step II: The carbon nanotube suspension obtained in Step I Placed in the syringe of the electrostatic spraying device, the syringe nozzle is connected to the positive electrode of the high-voltage electric field, and the carbon fiber prepreg cut into a certain size is used as the negative electrode receiver of the electrostatic spraying device, and the injector is pushed to uniformly spray the carbon nanotubes grafted with amino groups on the surface to the carbon fiber prepreg surface. The voltage of the high-voltage electric field of the spraying device is 18kV, and the receiving distance is 250mm; step III: the electrostatic spraying time is set to 30 minutes, and the thickness of the carbon nanotube coating layer obtained is 10 μm.

The prepreg is pressed into a unidirectional composite laminate with a thickness of 2mm by molding method, the pressure of the hot press is 10MPa, and the fiber volume content is 65%. When carbon nanotubes are not sprayed on the surface of the prepreg, the 0° compressive strength and modulus of the T700 carbon fiber composite unidirectional plate are 1450MPa and 150GPa, and the 90° compressive strength and modulus are 225MPa and 11.5GPa, respectively. The shear strength is 91.5MPa. After spraying amino-grafted carbon nanotubes on the surface of the prepreg, the 0° compressive strength and modulus of the T700 carbon fiber composite unidirectional plate are 1550MPa and 160GPa, and the 90° compressive strength and modulus are 256MPa and 12.9GPa, respectively. The interlaminar shear strength is 104 MPa.

Example 5

Component 1 is multi-walled carbon nanotubes grafted on the surface of 2,4-diethyl-toluenediamine, which is obtained by TNMC3 carboxylated multi-walled carbon nanotubes produced by Chengdu Zhongke Times Nano Co., Ltd. through acid chloride and amination treatment , the surface grafting rate of amino groups is 1.5wt%, the outer diameter of carbon nanotubes is 10~30nm, and the average length is 1μm; component 2 is N,N-dimethylformamide, the purity is ≥99%, Yangzhou Yaguan Chemical Co., Ltd.; component 3 is a self-made unidirectional prepreg of Toray ^® T700-12K carbon fiber/4,4′diaminodiphenylmethane tetraglycidylamine epoxy resin, and the curing agent is 4,4′di Aminodiphenylsulfone, with a thickness of 0.15mm and an areal density of 220g/m ² . Step Ⅰ: Add multi-walled carbon nanotubes grafted on the surface of 2,4-diethyl-toluenediamine to N,N-dimethylformamide, the mixing amount of carbon nanotubes is 10wt%, and ultrasonically oscillate for 1h A homogeneous mixture is formed. Put the ultrasonically oscillated mixture into a planetary ball mill and mill for 2 hours to obtain a uniform black suspension with an average aspect ratio of carbon nanotubes of 120; Step II: the carbon nanotube suspension obtained in Step I Placed in the syringe of the electrostatic spraying device, the syringe nozzle is connected to the positive electrode of the high-voltage electric field, and the carbon fiber prepreg cut into a certain size is used as the negative electrode receiver of the electrostatic spraying device, and the injector is pushed to uniformly spray the carbon nanotubes grafted with amino groups on the surface to the carbon fiber prepreg surface. The voltage of the high-voltage electric field of the spraying device is 18kV, and the receiving distance is 250mm; step III: the electrostatic spraying time is set to 60 minutes, and the thickness of the carbon nanotube coating layer obtained is 30 μm.

The prepreg is pressed into a unidirectional composite laminate with a thickness of 2mm by molding method, the pressure of the hot press is 10MPa, and the fiber volume content is 65%. When carbon nanotubes are not sprayed on the surface of the prepreg, the 0° compressive strength and modulus of the T700 carbon fiber composite unidirectional plate are 1450MPa and 150GPa, and the 90° compressive strength and modulus are 225MPa and 11.5GPa, respectively. The shear strength is 91.5MPa. After spraying amino-grafted carbon nanotubes on the surface of the prepreg, the 0° compressive strength and modulus of the T700 carbon fiber composite unidirectional plate were 1545MPa and 162GPa, and the 90° compressive strength and modulus were 252MPa and 13.8GPa, respectively. The interlaminar shear strength is 108 MPa.

Example 6

Component 1 is multi-walled carbon nanotubes grafted on the surface of 2,4-diethyl-toluenediamine, which is obtained by TNMC3 carboxylated multi-walled carbon nanotubes produced by Chengdu Zhongke Times Nano Co., Ltd. through acid chloride and amination treatment , the surface grafting rate of amino groups is 1.0wt%, the outer diameter of carbon nanotubes is 10-30nm, and the average length is 1μm; component 2 is tetrahydrofuran, with a purity of ≥99%, produced by Shanghai Nanze Chemical Co., Ltd.; component 3 is self-made Plain weave prepreg of Toray ^® T700-12K carbon fiber/4,4′ diaminodiphenylmethane tetraglycidylamine epoxy resin containing 4,4′ diaminodiphenyl sulfone as curing agent, thickness 0.15 mm, the areal density is 350g/m ² . Step I: adding multi-walled carbon nanotubes grafted on the surface of 2,4-diethyl-toluenediamine into tetrahydrofuran, the mixing amount of carbon nanotubes is 20wt%, and ultrasonically oscillating for 1 hour to form a uniform mixed solution. Put the ultrasonically oscillated mixture into a planetary ball mill and mill for 3 hours to obtain a uniform black suspension with an average aspect ratio of carbon nanotubes of 50; Step II: the carbon nanotube suspension obtained in Step I Placed in the syringe of the electrostatic spraying device, the syringe nozzle is connected to the positive electrode of the high-voltage electric field, and the carbon fiber prepreg cut into a certain size is used as the negative electrode receiver of the electrostatic spraying device, and the injector is pushed to uniformly spray the carbon nanotubes grafted with amino groups on the surface to the carbon fiber prepreg surface. The voltage of the high-voltage electric field of the spraying device is 18kV, and the receiving distance is 250mm; step III: the electrostatic spraying time is set to 120min, and the thickness of the carbon nanotube coating layer obtained is 80μm.

The prepreg was pressed into a plain weave laminate with a thickness of 2mm by molding method, the pressure of the hot press was 10MPa, and the fiber volume content was 63%. When carbon nanotubes are not sprayed on the surface of the prepreg, the 90° compressive strength and modulus of the T700 carbon fiber composite plate are 370MPa and 48.2GPa, respectively, and the interlaminar shear strength is 55.2MPa. After spraying amino-grafted carbon nanotubes on the surface of the prepreg, the 90° compressive strength and modulus of the T700 carbon fiber composite plate were 442MPa and 53.1GPa, respectively, and the interlaminar shear strength was 61.2MPa.

Claims (4)

1. A preparation method of amino-grafted carbon nanotube electrostatically sprayed carbon fiber/epoxy resin prepreg, characterized in that, comprising the following components and steps: Component 1: carbon nanotubes with amino grafted on the surface; component 2: Preferred electrostatic spray organic solvent; Component 3: Carbon fiber/epoxy resin prepreg; Step Ⅰ: Add carbon nanotubes grafted with amino groups on the surface to the preferred electrostatic spray organic solvent, ultrasonically oscillate evenly, carbon nanotubes The mixing amount in the electrostatic spray organic solvent is 3~20wt%; put the liquid mixture after ultrasonic oscillation into a planetary ball mill, and ball mill for 1~3 hours to obtain a uniform black suspension. The long diameter of carbon nanotubes after ball milling The ratio is controlled between 50 and 300, and the suspension is allowed to stand at room temperature for 1 day without delamination; Step Ⅱ: Put the carbon nanotube suspension obtained in Step Ⅰ into the syringe of the electrostatic spraying device, and the nozzle of the syringe is connected to a high-voltage electric field The positive electrode of the carbon fiber/epoxy resin prepreg cut into a certain size is used as the negative electrode receiver of the electrostatic spray device, and the injector is pushed to spray the amino-grafted carbon nanotubes evenly on the surface of the carbon fiber prepreg; Step Ⅲ: control The electrostatic spraying time is 30-120 minutes, and the carbon fiber/epoxy resin prepreg with different contents of amino-grafted carbon nanotubes sprayed on the surface is obtained, and the thickness of the carbon nanotube coating layer is 10-80 μm. 2. the preparation method of a kind of amino-grafted carbon nanotube electrostatic spraying carbon fiber/epoxy resin prepreg according to claim 1, wherein, the amino compound grafted on the carbon nanotube surface in component 1 is ethylenediamine , 2,4-diethyl-toluenediamine, and one or more of isophorone diamine, and the grafting rate of the amino compound on the surface of the carbon nanotube is 1.0-2.5wt%. 3. the preparation method of a kind of amino-grafted carbon nanotube electrostatic spraying carbon fiber/epoxy resin prepreg according to claim 1, wherein, the preferred electrostatic spraying organic solvent described in component 2 is N,N - dimethylformamide or tetrahydrofuran. 4. the preparation method of a kind of amino-grafted carbon nanotube electrostatic spraying carbon fiber/epoxy resin prepreg according to claim 1, wherein, the carbon nanotube/epoxy resin prepreg described in component 3 Includes unidirectional prepregs and fabric prepregs of carbon fibers.