CN111320841B - Aramid fiber/carbon nanotube composite reinforced carbon fiber resin prepreg - Google Patents

Abstract

The invention relates to an aramid fiber/Carbon Nanotube (CNT) composite reinforced carbon fiber resin prepreg which comprises the main components of carbon fiber, epoxy resin, aramid fiber and CNT. Compared with the common carbon fiber prepreg, the carbon fiber reinforced resin matrix Composite (CFRP) product formed by laminating and curing the product has improved mechanical properties such as bending strength, modulus, interlaminar shear strength and the like, so that the structural stability and impact resistance of the CFRP can be enhanced.

Description

Aramid fiber/carbon nanotube composite reinforced carbon fiber resin prepreg

Technical Field

The invention relates to the technical field of carbon fiber composite, in particular to an aramid fiber/Carbon Nanotube (CNT) composite reinforced carbon fiber resin prepreg.

Background

The carbon fiber reinforced resin matrix Composite (CFRP) is a layered composite prepared by taking thermosetting or thermoplastic resin as a matrix and carbon fiber or carbon fiber fabric as a reinforcement through a proper molding process. It combines the high strength of carbon fiber with the low specific gravity of resin, thus showing excellent comprehensive performance. Compared with the traditional metal material, the CFRP material has the advantages of high specific strength, low specific gravity, good fatigue resistance, small thermal expansion coefficient, good corrosion resistance, strong designability, good formability and the like, is widely applied to the field of aerospace, and is an important base material for modern large-scale civil aviation airliners. For example, in a Boeing B787 type passenger plane, the mass ratio of the CFRP structure reaches more than 50 percent; in an A350 type passenger plane of an air passenger, the mass ratio of a CFRP structure reaches over 53 percent. It can be said that CFRP materials are one of the most advanced composite materials in the world today.

The prepreg is a resin matrix and a reinforcement composition which are prepared by impregnating carbon fiber reinforcements with a resin matrix under strict control conditions, can be directly used for manufacturing and processing various composite material members, is a semi-finished product for manufacturing and producing CFRP materials, and forms a basic unit of the CFRP materials.

Because the CFRP material is prepared by combining a plurality of layers of prepregs, and a pure epoxy resin connecting layer with high brittleness exists between the layers of the internal structure of the CFRP material, the CFRP structure has the defects of low interlayer bonding strength, easy delamination damage and the like, and the stability and the safety of the whole structure are seriously influenced. Therefore, the key for improving the performance of the CFRP material lies in toughening the resin layer in the material structure and improving the impact resistance and delamination resistance of the material structure.

Common CFRP interlaminar reinforcement methods include short fiber toughening and nanoparticle toughening. The short fiber reinforcement means that high-strength and high-toughness short fibers are uniformly distributed in a resin layer between CFRP layers, when a structure is stressed, cracks are prevented from being generated and expanded through the bridging effect of the short fibers, and then the reinforcing effect is achieved. The nano particle toughening refers to the improvement of physical properties such as fracture toughness, impact resistance, tensile fracture strength and the like of epoxy resin by adding rigid nano particles, and the key problem of the technology is that the nano particles are difficult to uniformly disperse in the resin and are easy to cause adverse effects on structural properties due to the agglomeration of the nano particles.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an aramid fiber/CNT composite reinforced carbon fiber resin prepreg and a preparation method thereof. The main components of the product are carbon fiber, epoxy resin, aramid fiber and CNT, firstly, acetone is used as an organic solvent, the aramid fiber and the CNT are uniformly dispersed in the epoxy resin, then, the epoxy resin added with the aramid fiber and the CNT is combined with the carbon fiber by a pre-impregnator, and the aramid fiber/CNT composite reinforced carbon fiber resin prepreg is prepared by a roll-forming process.

The purpose of the invention is realized by the following technical scheme:

an aramid fiber/CNT composite reinforced carbon fiber resin prepreg comprises the following raw material components in percentage by mass:

epoxy resin: 100 parts of a binder;

carbon nanotube: 0.25 to 2 parts of

Aramid fiber: 0.25-2 parts;

carbon fiber: 67-400 parts.

The carbon fiber is unidirectional carbon fiber yarn or carbon fiber woven cloth;

the aramid fiber is chopped fiber or pulp, the length of the aramid chopped fiber is 1-12 mm, and the length of the aramid pulp fiber is less than 1 mm.

The CNT is a single-walled carbon nanotube or a multi-walled carbon nanotube, the diameter of the single-walled carbon nanotube is less than 2nm, and the length of the single-walled carbon nanotube is more than 5 mu m; the diameter of the multi-wall carbon nano tube is more than 7nm, and the length of the multi-wall carbon nano tube is more than 5 mu m.

A preparation method of an aramid fiber/CNT composite reinforced carbon fiber resin prepreg comprises the following specific processes:

the production equipment is mainly a common pre-soaking machine and is processed by the processes of coating, hot pressing, cooling, laminating, curling and the like, and additional transformation on processing equipment is not needed.

A preparation method of an aramid fiber/CNT composite reinforced carbon fiber resin prepreg comprises the following specific steps:

(1) placing the aramid fiber and the CNT in a forced air drying box for fully drying, and removing the moisture absorbed inside;

the specific drying temperature is 90 ℃, and the time is 24 hours;

(2) mixing 10 wt% of epoxy resin A component with the same amount of acetone, continuously stirring and gradually adding CNT for multiple times until the epoxy resin A component is completely dissolved and the CNT is uniformly dispersed;

the epoxy resin is divided into two parts: the component A is a resin part, the component B is a curing agent part, and only the component A is used;

the mass ratio of acetone used is 1: 1 is added into the epoxy resin A component;

(3) adding the mixed solution of the epoxy resin A component, acetone and CNT into the aramid fiber, and fully and uniformly stirring to ensure that the epoxy resin fully wets the aramid fiber;

because acetone has good permeability, the resin and the CNT can be penetrated into the staggered pore structure of the aramid fiber after the component A of the epoxy resin is dissolved, so that the epoxy resin is fully wetted and wraps the aramid fiber and the CNT, and the CNT is inhibited from agglomerating.

(4) Placing the mixture in a forced air drying oven, and carrying out heat treatment at 90 ℃ until the acetone is completely volatilized;

the specific heat treatment method comprises the following steps: the mixture was taken out every 30min and stirred manually, weighed and the weight of the mixture was recorded until the weight did not drop any more, at which point the acetone was completely volatilized.

(5) Adding therest 90 wt% of the epoxy resin A component into the mixture for multiple times, and continuously stirring for more than 12 hours until the aramid fiber and the CNT are completely dispersed in the epoxy resin A component;

the viscosity of the resin can be reduced by heating at the time of the stirring treatment.

(6) The epoxy resin B component (curing agent) is added according to the proportion, and is mixed and homogenized by a three-roll grinder.

(7) And coating, hot-pressing and cooling on a glue spreader to prepare the aramid fiber/CNT composite epoxy resin film.

(8) And (3) combining the prefabricated aramid fiber/CNT composite epoxy resin film with the carbon fiber by using a pre-soaking machine, and preparing the aramid fiber/CNT composite reinforced carbon fiber resin pre-soaking material by using film covering and curling processes.

Compared with the prior art, the invention has the positive effects that:

the preparation method of the product is simple, the existing production equipment such as a pre-soaking machine and the like is not required to be greatly modified, the addition amount of the reinforcing agent is small, and the improvement cost is low.

According to the application, high-strength and high-toughness aramid fibers and rigid nano-particles CNT are taken as reinforcing agents and introduced into a carbon fiber resin prepreg and distributed between layers of a CFRP material, as shown in figure 1. The bonding strength between layers of the CFRP material can be improved through the bridging action of the aramid fibers, the generation and the expansion of cracks between the layers are inhibited, and meanwhile, the toughness and the strength of the interlayer resin are improved through the toughening action of the nano particle CNT, so that the mechanical properties such as the strength, the modulus, the toughness and the like of the CFRP material are improved, the structural stability of the material is improved, and the problems that the CFRP material is high in interlayer resin brittleness and easy to break in a layered structure are effectively solved.

Drawings

FIG. 1 is an optical micrograph of a section of an aramid fiber/CNT composite reinforced CFRP material, wherein a is a carbon fiber layer, and b is an aramid fiber/CNT composite reinforced interlayer epoxy resin layer;

FIG. 2 is a photograph comparing a common carbon fiber resin prepreg sample with an aramid fiber/CNT composite reinforced carbon fiber resin prepreg; a is a common sample photo, and b is a photo of an aramid fiber/CNT composite reinforced carbon fiber prepreg sample;

fig. 3 is a comparison of the mechanical properties of the CFRP sample without aramid fiber and the CFRP sample reinforced by aramid fiber/CNT composite.

Detailed Description

The following provides a specific embodiment of an aramid fiber/CNT composite reinforced carbon fiber resin prepreg and a preparation method thereof.

Example 1

And preparing the aramid fiber/CNT composite reinforced unidirectional carbon fiber resin prepreg.

Raw materials: the carbon fiber is 12K T300 industrial grade unidirectional carbon fiber filament produced by renaturation hawk limited in China, the spreading width of the carbon fiber is 1m, and the density of the fiber distribution surface is 150g/m² (ii) a The epoxy resin is MT3 type epoxy resin produced by Shaoxing composite Co., Ltd, the curing temperature is 130 ℃, and the designed resin distribution surface density is about 80g/m² (ii) a The aramid fiber is Kevlar (Kevlar-29) aramid pulp produced by Dupont company (Dupont) in the United states, the fiber length is less than or equal to 1mm, and the fiber diameter is less than or equal to 1 mu m; the CNT used is an industrial multi-walled carbon nanotube produced by Nangang Limited of Shenzhen, China, and the model is as follows: NTP3003 with an outer diameter of 7-15nm, an average length of 5-15 μm, a purity of > 95%, a specific surface area of about 200-² (ii) in terms of/g. Designing the prepreg to have the following components in mass ratio: aramid fiber: 0.9 part; CNT: 0.1 part; epoxy resin: 100 parts of (A); carbon fiber: 200 parts.

The preparation method comprises the following steps: mixing 10 wt% of epoxy resin A component with acetone in the same amount, adding CNT for multiple times while stirring until the resin is completely dissolved and the CNT is uniformly dispersed in the solution, and then adding the solution into dry aramid pulp and uniformly mixing. The mixture was placed in a forced air drying oven and heat treated at 60 ℃ with intermittent stirring until the mixture quality did not decrease any more, at which point the acetone was completely volatilized. And adding the rest of the epoxy resin A component into the mixture for multiple times, continuously stirring and heating for 12 hours until the aramid fiber and the CNT are uniformly dispersed in the epoxy resin. Then proportionally mixing the component B of the epoxy resin (curing agent), grinding and homogenizing.

And finally, preparing the aramid fiber reinforced carbon fiber resin prepreg by using a prepreg machine through the processes of coating, hot pressing, cooling, laminating, curling and the like.

The photo of the prepared aramid fiber reinforced carbon fiber prepreg sample is shown in fig. 2. The surface of a common carbon fiber prepreg sample is bright, the color of the aramid fiber is covered by black CNT on the surface of the aramid fiber/CNT composite reinforced carbon fiber prepreg, the outline of a small amount of aramid fiber can be observed in a concealed mode, but the surface color of the prepreg is uniform, and no large block of agglomerate is generated, which shows that the aramid fiber and the CNT are uniformly distributed on the surface of the prepreg.

The two prepregs are subjected to hot press forming under the same condition to prepare a CFRP laminated plate sample (the forming method comprises compression molding, the forming pressure is 1MPa, the curing temperature rise system is 85-30 min, and 130-2 h), and the mechanical properties of different items are carried out, and the test result is shown in figure 3. Test results show that the reinforcing effects of the aramid fiber and the CNT are combined, the multiple mechanical properties of the CFRP material are obviously improved, and the bending strength improvement rate of the 0-degree fiber direction reaches 7.80 percent; the improvement rate of the flexural modulus in the 0-degree fiber direction reaches 6.96 percent; the bending strength improvement rate of the 90-degree fiber direction reaches 10.11 percent; the lifting rate of the interlaminar shear strength is the maximum and reaches 16.75 percent. The results show that the strength and toughness of the resin between layers of the CFRP material are greatly enhanced due to the combined action of the interlayer bridging of the aramid fiber and the toughening of the nano particles of the CNT, the generation and the expansion of cracks are hindered, the interlayer bonding force of the CFRP is improved, and the structural stability and the safety of the CFRP material are greatly enhanced.

Compared with the common carbon fiber prepreg, the carbon fiber reinforced resin matrix Composite (CFRP) product formed by laminating and curing the product has improved mechanical properties such as bending strength, modulus, interlaminar shear strength and the like, so that the structural stability and impact resistance of the CFRP can be enhanced.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the concept of the present invention, and these modifications and decorations should also be regarded as being within the protection scope of the present invention.

Claims (7)

1. The aramid fiber/carbon nanotube composite reinforced carbon fiber resin prepreg is characterized by comprising the following raw material components in percentage by mass:

epoxy resin: 100 parts of (A);

carbon nanotube: 0.25 to 2 portions of

Aramid fiber: 0.25-2 parts;

carbon fiber: 67 to 400 portions of

The preparation method of the aramid fiber/CNT composite reinforced carbon fiber resin prepreg comprises the following specific steps:

(1) placing the aramid fiber and the CNT in a forced air drying box for fully drying, and removing the moisture absorbed inside;

(2) mixing 10 wt% of epoxy resin A component with the same amount of acetone, continuously stirring and gradually adding CNT for multiple times until the epoxy resin A component is completely dissolved and the CNT is uniformly dispersed;

the epoxy resin is divided into two parts: the component A is a resin part, the component B is a curing agent part, and only the component A is used;

(3) adding the mixed solution of the epoxy resin A component, acetone and CNT into the aramid fiber, and fully and uniformly stirring to fully wet the solution and wrap the aramid fiber;

(4) placing the mixture in a forced air drying oven, and carrying out heat treatment at 90 ℃ until the acetone is completely volatilized;

(5) adding the rest 90 wt% of the epoxy resin A component into the mixture for multiple times, and continuously stirring for more than 12 hours until the aramid fiber and the CNT are uniformly dispersed in the epoxy resin A component;

(6) adding the epoxy resin B component according to the proportion, and mixing and homogenizing by using a three-roll grinder;

(7) coating, hot-pressing and cooling on a glue spreader to prepare an aramid fiber/CNT composite epoxy resin film;

(8) and (3) combining the prefabricated aramid fiber/CNT composite epoxy resin film with carbon fibers by using a pre-impregnator, and preparing the aramid fiber/CNT composite reinforced carbon fiber resin prepreg through film covering and curling processes.

2. The aramid fiber/CNT composite reinforced carbon fiber resin prepreg as claimed in claim 1, wherein the carbon fiber is a unidirectional carbon fiber filament or a carbon fiber woven cloth.

3. The aramid fiber/CNT composite reinforced carbon fiber resin prepreg of claim 1, wherein the aramid fiber is chopped fiber or pulp, the length of the aramid chopped fiber is 1-12 mm, and the length of the aramid pulp fiber is less than 1 mm.

4. The aramid fiber/CNT composite reinforced carbon fiber resin prepreg of claim 1, wherein the CNT is a single-walled carbon nanotube or a multi-walled carbon nanotube, the diameter of the single-walled carbon nanotube is less than 2nm, and the length of the single-walled carbon nanotube is more than 5 μm; the diameter of the multi-wall carbon nano tube is more than 7nm, and the length of the multi-wall carbon nano tube is more than 5 mu m.

5. The aramid fiber/CNT composite reinforced carbon fiber resin prepreg as claimed in claim 1, wherein the specific drying temperature of the raw materials is 90 ℃ and the time is 24 hours.

6. The aramid fiber/CNT composite reinforced carbon fiber resin prepreg as claimed in claim 1, wherein the acetone is used in a mass ratio of 1: 1 is added into the epoxy resin A component.

7. The aramid fiber/CNT composite reinforced carbon fiber resin prepreg of claim 1, wherein the heat treatment method comprises the following specific steps: the mixture was taken out every 30min and stirred manually, weighed and the weight of the mixture was recorded until the weight did not drop any more, at which point the acetone was completely volatilized.

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