KR20230001090A - Carbon fibers-reinforced epoxy composites with graphene oxide/graphitic nanofibers composites and manufacturing method thereof - Google Patents

Abstract

The present invention provides a manufacturing method of a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs, which comprises the steps of (1) performing ozone treatment of graphite nanofibers (GNFs); (2) surface-modifying the GNFs; (3) washing the GNFs with tetrahydrofuran (THF); (4) compounding the tetrahydrofuran with graphene oxide (GO); (5) removing remaining graphite nanofibers or graphene oxide residues followed by washing and drying; (6) mixing the graphene oxide/graphite nanofiber composite with an epoxy resin; (7) stabilizing the mixture of the graphene oxide/graphite nanofiber composite and the epoxy resin; (8) adding 4,4'-diaminodiphenylmethane (DDM) as a curing agent to the epoxy resin mixture to proceed with a curing reaction; (9) stabilizing the mixture in a vacuum oven; and (10) impregnating the carbon fibers with the mixture of a graphene oxide/graphite nanofiber composite, the epoxy resin, and the curing agent and curing the mixture through a hot press.

Description

Carbon fiber reinforced epoxy composite material reinforced with graphene oxide/graphite nanofiber composite and method for manufacturing the same

The present invention is to reinforce carbon fibers (CFs) reinforced with a graphene oxide/graphite nanofiber (GO-GNF) composite in which graphene oxide (GO) and graphite nanofibers (GNFs) are combined. It relates to an epoxy composite material and a manufacturing method thereof, and more particularly, to a carbon fiber reinforced epoxy composite material reinforced with GO-GNF having improved interfacial properties and mechanical strength of the carbon fiber reinforced epoxy composite material and a manufacturing method thereof.

Epoxy, which has two or more epoxy groups (C-O-C) in its molecule, can be cured with carbon fibers to produce hard, insoluble carbon fibers-reinforced polymer composites (CFRPs). Due to the high tensile modulus, adhesive properties, chemical resistance, and structural stability of epoxy and the high strength, low specific gravity, and strong chemical resistance of carbon fiber, it is emerging as a good alternative to polymer composites reinforced with carbon fiber. , ships, automobile parts, marine equipment, electric and electronic industries, etc. However, carbon fibers exhibit poor interfacial adhesion within the epoxy matrix due to structural defects and chemically inert surfaces. This problem deteriorates interfacial properties and mechanical strength, which can be a limitation in various modern industrial fields.

On the other hand, recently, studies introducing methods such as combining other polymers, carbon materials, and nano-sized particles in order to improve these interface properties and mechanical strength have been confirmed.

Among various filler materials, carbon materials can be combined with an epoxy matrix to significantly improve interfacial properties and mechanical strength. Among various carbon materials, graphite nanofibers (GNFs) provide functionality that can deliver the excellent properties of the nanoscale to the microscale. However, GNFs are inherently hydrophobic, and there is difficulty in self-aggregation of GNFs in relation to interfacial interactions within the epoxy matrix due to van der Waals forces between particles. The structure of graphite nanofibers is formed with basal plane and prismatic surfaces structures, and among them, prismatic surfaces are more active than basal planes, so problems can be solved through composite with graphene oxide (GO).

GO can significantly improve interfacial properties and mechanical strength by being composited with an epoxy matrix. Oxygen-containing functional groups such as -OH, -C=O, and -COOH of GO enhance the interfacial adhesion within the epoxy matrix to promote interaction with the epoxy resin. In particular, GO can solve the problem of aggregation of GNFs, and there are research cases that greatly improve the mechanical properties and thermal conductivity of carbon fiber reinforced epoxy composites by forming composites with other carbon materials.

An object of the present invention is to provide a carbon fiber reinforced epoxy composite material having improved interfacial properties and mechanical strength, using a graphene oxide/graphite nanofiber composite having improved interfacial properties and mechanical strength, a graphene oxide/graphite nanofiber composite. To provide a carbon fiber reinforced epoxy composite material and manufacturing method.

In order to achieve the above object, the present invention provides a carbon fiber reinforced epoxy composite material and manufacturing method with improved interfacial properties and mechanical strength.

The method for manufacturing a carbon fiber reinforced epoxy composite material reinforced with GO-GNF of the present invention includes the steps of (1) modifying the surface of graphite nanofibers using a dry ozone generator; (2) after ozone treatment, using a SOCl ₂ (Thionyl chloride) solution used for surface modification to perform a S _N 2 substitution reaction; (3) washing with THF (Tetrahydrofuran) to prevent hydrolysis after the substitution reaction; (4) after washing, combining graphene oxide/graphite nanofibers to form a composite with graphene oxide; (5) washing with ethanol and distilled water and drying to remove residual flakes; (6) mixing the graphene oxide/graphite nanofiber composite prepared by the above method with an epoxy resin using an organic solvent; (7) stabilizing the prepared mixture; (8) adding and mixing a curing agent; (9) stabilizing the prepared mixture in a vacuum oven; Carbon fiber reinforced with GO-GNF comprising the step (10) of preparing a carbon fiber reinforced epoxy composite material reinforced with graphene oxide/graphite nanofibers by impregnating the prepared mixture with carbon fibers and curing by hot pressing. Provides a method for manufacturing an epoxy composite material. More specifically, in step (8), 100 g of epoxy resin, 4,4'-diaminodiphenylmethane as a curing agent, 34 g to 36 g in equivalent ratio to the epoxy resin, GO-GNF 0.3 g to 1.0 g, and in step (10) The carbon fibers may include those of 50 g.

According to the present invention, by adding GO-GNFs as a filler to an epoxy resin, many oxygen-containing functional groups of GO-GNFs lead to strong interfacial interaction and adhesive force with the thermosetting epoxy resin, resulting in interfacial properties and mechanical strength. There is an effect that an improved carbon fiber reinforced epoxy composite material is manufactured.

1 is a comparison graph of the surface energy and improvement degree of a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs according to an embodiment of the present invention and a comparative example.
Figure 2 is a comparative graph of interlaminar shear strength (ILSS) and improvement degree of a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs according to an embodiment of the present invention and a comparative example.
3 is a comparative graph of the fracture toughness and degree of improvement of a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs according to an embodiment of the present invention and a comparative example.
Figure 4 is a SEM picture of the fracture surface after measuring the fracture toughness of Example 3, Comparative Example 3 and Comparative Example 7 of the carbon fiber-reinforced epoxy composite material reinforced with GO-GNFs prepared in the present invention.

Hereinafter, the present invention will be described in detail.

A method for manufacturing a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs according to one type of the present invention includes: 1) modifying the surface of graphite nanofibers using a dry ozone generator; (2) after ozone treatment, using SOCl ₂ (Thionyl chloride) solution used for surface modification, _SN 2 substitution reaction step; (3) washing with THF (Tetrahydrofuran) to prevent hydrolysis after the substitution reaction; (4) after washing, combining graphene oxide/graphite nanofibers to form a composite with graphene oxide; (5) washing with ethanol and distilled water and drying to remove residual flakes; (6) mixing the graphene oxide/graphite nanofiber composite prepared by the above method with an epoxy resin using an organic solvent; (7) stabilizing the prepared mixture; (8) adding and mixing a curing agent; (9) stabilizing the prepared mixture in a vacuum oven; The epoxy mixture prepared in steps (6), (7), and (8) is impregnated with carbon fiber and cured by hot pressing to prepare a carbon fiber reinforced epoxy composite material reinforced with graphene oxide / graphite nanofibers (10) Provides a method for manufacturing a carbon fiber reinforced epoxy composite material reinforced with GO-GNF.

More specifically, in step (8), 100 g of epoxy, 4,4'-diaminodiphenylmethane as a curing agent, 34 g to 36 g in equivalent ratio to the epoxy resin, GO-GNF 0.3 g to 1.0 g, and carbon in step (10) Fibers may include those that are 50 g.

A carbon fiber reinforced epoxy composite material reinforced with GO-GNFs according to an aspect of the present invention is obtained by adding GO-GNFs to an epoxy matrix.

Looking at the manufacturing process of the present invention in detail, (1) an ozone generator (Ozone Tech Co. Lab II, Korea) was used at an ozone gas flow rate of 0.1 to 0.8 l/min and a pressure of 0.01 to 0.08 MPa for 1 to 10 hours. Graphite nanofibers were modified.

(2) After ozone treatment in step (1), 100 mL to 500 mL of SOCl ₂ (Thionyl chloride) solution used for surface modification was heated and maintained in the temperature range of 10 ° C to 50 ° C for 1 hour to 4 hours. It is preferable to proceed with the S _N 2 substitution reaction by reacting.

(3) After the substitution reaction in step (2), the mixture was washed with 100 mL to 500 mL of THF to prevent hydrolysis and dried in a vacuum oven at 60 °C for 1 to 12 hours. When the hydrolysis reaction proceeds, it is difficult to maintain the oxygen-containing functional groups on the surface of the graphite nanofibers, so it is impossible to proceed with the composite with graphene oxide.

(4) After THF washing and drying in step (3), composite was performed by reacting graphite nanofibers with graphene oxide for 1 hour to 4 hours at a temperature range of 10 ° C to 70 ° C.

(5) In step (4), the graphene oxide/graphite nanofiber composite was washed with 500 mL of 100 mL of ethanol and 500 mL of 100 mL of distilled water, and dried in a vacuum oven at 60 ° C for 1 to 12 hours to graphene oxide / A graphite nanofiber composite was obtained.

In the case of the washing and drying process of step (5), it is essential to remove remaining graphene oxide and graphite nanofibers that have not been formed into a graphene oxide/graphite nanofiber composite.

(6) In step (5), the graphene oxide/graphite nanofiber composite was mixed with an epoxy resin using an organic solvent. Looking at this process, 0.3 g to 1.0 g of GO-GNFs compared to epoxy resin was added to 50 mL to 200 mL of acetone (C ₃ H ₆ O), followed by sonication for 1 to 2 hours at a temperature range of 10 ° C to 50 ° C. proceed with After adding an epoxy resin to the GO-GNFs mixture after the reaction, it was maintained by heating in the range of 30 ° C to 65 ° C and stirred for 1 hour to 4 hours.

The stabilization step of step (7) was performed using the epoxy mixture prepared in step (6). It is preferable to remove the organic solvent from the prepared epoxy mixture at a temperature range of 100 ° C to 150 ° C for 4 to 10 hours. If the organic solvent remains, it must be removed because bubbles are formed in the curing reaction. These bubbles deteriorate the interface properties and mechanical properties.

(8) A step of mixing by adding a curing agent to the epoxy mixture from which the organic solvent was removed in step (7) was performed. In this process, 4,4'-diaminodiphenylmethane as a curing agent is added in an equivalent ratio to the epoxy resin and reacted at a temperature range of 20 ℃ to 70 ℃ for 1 to 5 hours. In the curing reaction of the epoxy resin, the curing agent should be added according to the equivalent ratio of difunctionality of the epoxy resin. More specifically, 34% to 36% by weight of the curing agent based on 100% by weight of the epoxy resin is added. When the curing agent is added in excess of the equivalent ratio, the crosslinking density is increased and the mechanical properties are deteriorated due to brittleness. When the curing agent is added in an equivalent ratio, the formation of a three-dimensional network structure is limited, and the mechanical properties are deteriorated due to the low crosslinking density.

(9) The step of stabilizing the epoxy mixture during the curing reaction in the vacuum oven in step (8) is a problem in which a curing agent is added to the epoxy resin and bubbles are generated due to a chemical reaction, and the temperature range is 10 ° C to 60 ° C under vacuum in a vacuum oven. It is preferable to remove air bubbles from 1 hour to 3 hours. As described above, bubbles generated during the curing process may form pores (voids) in the finally prepared epoxy composite material, thereby reducing the interface, thermal conductivity, and mechanical strength.

(10) Using a hot press, the epoxy mixture stabilized in step (9) is heated for 1 hour to 2 hours (stabilization step) in the temperature range of 60 ° C to 90 ° C in the first step, and 90 ° C to 125 ° C in the second step. In the range of 1 to 2 hours (temporary curing step), the third step is 1 hour to 2 hours (curing step) in the temperature range of 140 ° C to 170 ° C. Epoxy composites were prepared. If the three curing processes are not performed in step (10), pores may be formed and interface properties and mechanical strength may be deteriorated. In addition, if the curing temperature is less than 110 ° C, it is not completely cured, and if the curing temperature is higher than 170 ° C, Part of the epoxy resin is decomposed, resulting in deterioration of physical properties.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as being limited by these examples.

Example 1.

Using an ozone generator (Ozone Tech Co. Lab II, Korea), the graphite nanofibers were modified for 1 to 10 hours at an ozone gas flow rate of 0.1 to 0.8 l/min and a pressure of 0.01 to 0.08 MPa. After ozone treatment, 100 mL to 500 mL of SOCl ₂ (Thionyl chloride) solution used for surface modification is heated and maintained in the temperature range of 10 ° C to 50 ° C, and reacted for 1 hour to 4 hours to perform the _SN 2 substitution reaction. proceeded. After the substitution reaction, to prevent hydrolysis, the mixture was washed with 100 mL to 500 mL of THF and dried in a vacuum oven at 60 °C for 1 hour to 12 hours. Then, composite was performed by reacting graphite nanofibers and graphene oxide for 1 hour to 4 hours at a temperature range of 10 ° C to 70 ° C. Thereafter, it was washed using 500 mL of 100 mL of ethanol and 500 mL of 100 mL of distilled water, and dried in a vacuum oven at 60 ° C for 1 hour to 12 hours to prepare a graphene oxide / graphite nanofiber composite.

Then, as an organic solvent, acetone (C ₃ H ₆ O) was added to 50 mL to 200 mL of 0.3% by weight of graphene oxide / graphite nanofiber composite relative to 100% by weight of epoxy resin, and then 1 Sonication was carried out for 2 h. After adding 100 g of epoxy resin to the graphene oxide/graphite nanofiber mixture after the reaction, the mixture was heated and maintained in the range of 30° C. to 65° C. and stirred for 1 hour to 4 hours. Then, it was removed for 4 hours to 10 hours at a temperature range of 100 ℃ to 150 ℃ to remove the organic solvent. Then, DDM (4,4'-diaminodiphenylmethane) as a curing agent in the graphene oxide/graphite nanofiber composite and the epoxy resin mixture was added at an equivalent ratio of 34 to 36% by weight relative to 100% by weight of the epoxy resin as an equivalent ratio to the bifunctional epoxy resin. It was added and reacted for 1 hour to 5 hours at a temperature range of 20 ° C to 70 ° C. Thereafter, air bubbles were removed in a vacuum oven at a temperature range of 10° C. to 60° C. for 1 hour to 3 hours under reduced pressure. Then, a hardening process is performed in a hot press. The first step is 1 to 2 hours in the temperature range of 60 ° C to 90 ° C, the second step is 1 to 2 hours in the temperature range of 90 ° C to 125 ° C, and the third step is 140 ° C In the temperature range of 170 ° C., the epoxy composite material reinforced with the graphene oxide / graphite nanofiber composite was prepared by curing for 3 hours to 6 hours in a total of 3 steps from 1 hour to 2 hours.

Example 2.

A carbon fiber reinforced epoxy composite material reinforced with GO-GNFs was prepared by performing the same process as in Example 1, but with the content of GO-GNFs being 0.5% by weight.

Example 3.

A carbon fiber-reinforced epoxy composite material reinforced with GO-GNFs was prepared by performing the same process as in Example 1, but with the content of GO-GNFs being 0.8% by weight.

Example 4.

A carbon fiber-reinforced epoxy composite material reinforced with GO-GNFs was prepared by performing the same process as in Example 1, but with the content of GO-GNFs being 1.0% by weight.

Comparative Example 1.

Graphite nanofibers (GNFs) were mixed with an epoxy resin using an organic solvent. Specifically, after adding 0.3% by weight of GFs relative to 100% by weight of epoxy resin in 50 mL to 200 mL of acetone (C ₃ H ₆ O) as an organic solvent, 1 to 2 hours at a temperature range of 10 ° C to 50 ° C during sonication. After adding 100 g of epoxy resin to the GNFs mixture after the reaction, it was heated and maintained at a temperature range of 30 to 65 ° C and stirred for 1 hour to 4 hours. Then, the organic solvent was removed for 4 hours to 10 hours at a temperature range of 100 ℃ to 150 ℃. Then, DDM (4,4'-diaminodiphenylmethane) as a curing agent to the remaining GNFs and epoxy resin was added in an equivalent ratio of 34% to 36% by weight relative to 100% by weight of the epoxy resin, and the temperature range was 20 ° C to 70 ° C. reacted for 1 hour to 5 hours. Thereafter, air bubbles were removed in a vacuum oven at a temperature range of 45° C. to 65° C. for 1 hour to 3 hours under reduced pressure. Then, after manually impregnating the mold with carbon fiber, the first step in the hot press is 1 hour to 2 hours in the temperature range of 60 ° C to 90 ° C, and the second step is 1 hour to 2 hours in the temperature range of 90 ° C to 125 ° C. prepared a carbon fiber-reinforced epoxy composite material reinforced with GNFs by curing for 3 to 6 hours in a total of three steps, from 1 hour to 2 hours at a temperature range of 140 ° C to 170 ° C.

Comparative Example 2.

A carbon fiber-reinforced epoxy composite material reinforced with GNFs was prepared by performing the same process as in Comparative Example 1, but using a GNFs content of 0.5% by weight.

Comparative Example 3.

The process was carried out in the same manner as in Comparative Example 1, but the content of GNFs was 0.8% by weight to prepare a carbon fiber reinforced epoxy composite material reinforced with GNFs.

Comparative Example 4.

The process was carried out in the same manner as in Comparative Example 1, but the content of GNFs was 1.0% by weight to prepare a carbon fiber reinforced epoxy composite material reinforced with GNFs.

Comparative Example 5.

Using an ozone generator (Ozone Tech Co. Lab II, Korea), the graphite nanofibers were modified for 1 to 10 hours at an ozone gas flow rate of 0.1 to 0.8 l/min and a pressure of 0.01 to 0.08 MPa. Then, 0.3% by weight of ozone-treated Graphene Nano Fibers (OGNFs) was added to 50mL to 200mL of acetone (C ₃ H ₆ O) as an organic solvent, compared to 100% by weight of epoxy resin, and then heated at 10 ° C. ultrasonic treatment for 1 to 2 hours in the temperature range of 50 ° C. After adding 100 g of epoxy resin to the OGNFs mixture after the reaction, the mixture was heated and maintained in the range of 30 ° C to 65 ° C and stirred for 1 hour to 4 hours. Then, in order to remove the organic solvent, it was removed for 4 to 10 hours at a temperature range of 100 ° C to 150 ° C. Then, DDM (4,4'-diaminodiphenylmethane) as a curing agent to the remaining OGNFs and epoxy resin mixture was added in an equivalent ratio of 34 to 36% by weight relative to 100% by weight of the epoxy resin as an equivalent ratio to the bifunctional epoxy resin at 20 ° C. It was reacted for 1 hour to 5 hours in the temperature range of 70 ℃. Thereafter, air bubbles were removed in a vacuum oven at a temperature range of 10° C. to 60° C. for 1 hour to 3 hours under reduced pressure. Then, a hardening process is performed in a hot press. The first step is 1 hour to 2 hours in the temperature range of 60 ° C to 90 ° C, the second step is 1 hour to 2 hours in the temperature range of 90 ° C to 125 ° C, and the third step is 140 ° C. A carbon fiber-reinforced epoxy composite material reinforced with OGNFs was prepared by curing for 3 to 6 hours in a total of three steps, from 1 hour to 2 hours at a temperature of 170 ° C.

Comparative Example 6.

The process was carried out in the same manner as in Comparative Example 5, but the content of OGNFs was 0.5% by weight to prepare a carbon fiber reinforced epoxy composite material reinforced with OGNFs.

Comparative Example 7.

The process was carried out in the same manner as in Comparative Example 5, but the content of OGNFs was 0.8% by weight to prepare a carbon fiber reinforced epoxy composite material reinforced with OGNFs.

Comparative Example 8.

The process was carried out in the same manner as in Comparative Example 5, but the content of OGNFs was 1.0% by weight to prepare a carbon fiber reinforced epoxy composite material reinforced with OGNFs.

Measurement Example 1. Surface free energy test of carbon fiber reinforced epoxy composite material reinforced with GO-GNFs, GNFs and OGNFs prepared in the present invention

Surface free energies were measured using a Rame-Hart goniometer (Phoenix 300 Plus, SEO Co.) enriched with GO-GNFs, GNFs and OGNFs for three standard wetting solutions (distilled water, diiodomethane, ethylene glycol). The contact angle of the carbon fiber reinforced epoxy composite was measured and tested.

Measurement Example 2. ILSS test of carbon fiber reinforced epoxy composite material reinforced with GO-GNFs, GNFs and OGNFs prepared in the present invention

In the ILSS test, carbon fiber reinforced epoxy composite materials reinforced with GO-GNFs, GNFs, and OGNFs were prepared according to ASTM D-2344 using a universal testing machine (Lloyd LR5k), and then tested using a short-beam 3-point bending test method. measured.

Measurement Example 3. Fracture toughness test of carbon fiber reinforced epoxy composites reinforced with GO-GNFs, GNFs and OGNFs prepared in the present invention

For the fracture toughness test, specimens were prepared according to ASTM E399 for carbon fiber reinforced epoxy composite materials reinforced with GO-GNFs, GNFs, and OGNFs using a universal testing machine (Lloyd LR5k), and then measured by a 3-point bending test method.

Measurement Example 4. Observation of fracture surface after fracture toughness test of carbon fiber reinforced epoxy composite material reinforced with GO-GNFs, GNFs and OGNFs prepared in the present invention

In the present invention, scanning electron microscopy (SEM, SU 8010, Hitachi, Ltd., Japan) was used to observe whether the structure of carbon fiber reinforced epoxy composites reinforced with GO-GNFs, GNFs, and OGNFs was changed.

The manufacturing conditions of the carbon fiber reinforced epoxy composite material reinforced with GO-GNFs, GNFs and OGNFs according to the present invention are shown in Table 1 below, and the surface energy, ILSS, fracture toughness and improvement degree, and numerical values of the manufactured composite material are shown in Table 1 below. shown in 2.

In the above, specific parts of the present invention have been described in detail, for those skilled in the art, it is clear that these specific descriptions are only preferred embodiments, and the scope of the present invention is not limited thereby. something to do. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (11)

(1) ozonating graphite nanofibers (GNFs) using a dry ozone generator;
(2) surface-modifying the ozone-treated graphite nanofibers in step (1) through a S _N 2 substitution reaction using SOCl ₂ (Thionyl chloride) solution;
(3) washing with THF (Tetrahydrofuran) to prevent hydrolysis of the graphite nanofibers surface-modified in step (2);
(4) combining the graphite nanofibers prepared in step (3) with graphene oxide (GO);
(5) removing remaining graphite nanofibers or graphene oxide residues other than the graphene oxide/graphite nanofiber composite (GO-GNF) prepared in step (4), washing with ethanol and distilled water, and drying;
(6) mixing the graphene oxide/graphite nanofiber composite prepared in step (5) with an epoxy resin using acetone as an organic solvent;
(7) stabilizing the mixture of the graphene oxide/graphite nanofiber composite prepared in step (6) and the epoxy resin;
(8) performing a curing reaction by adding DDM (4,4'-diaminodiphenylmethane) as a curing agent to the epoxy resin mixture prepared in step (7);
(9) stabilizing the mixture prepared in step (8) in a vacuum oven;
(10) impregnating the mixture of the graphene oxide/graphite nanofiber composite prepared in step (9), an epoxy resin, and a curing agent with carbon fibers and hardening through hot pressing; Method for producing a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs comprising a. According to claim 1,
In step (1), using a dry ozone generator, ozonating the graphite nanofibers for 1 hour to 10 hours under the conditions of an ozone gas flow rate of 0.1 l/min to 0.8 l/min and a pressure of 0.01 MPa to 0.08 MPa , Manufacturing Method of Carbon Fiber Reinforced Epoxy Composites Reinforced with GO-GNFs. According to claim 1,
In step (2), 100 mL to 500 mL of SOCl ₂ was added to the ozonated graphite nanofibers, heated and maintained at a temperature range of 10 ° C to 50 ° C, and reacted for 1 hour to 4 hours to induce a _SN 2 substitution reaction. Method for manufacturing a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs. According to claim 1,
In step (3), washing with 100 mL to 500 mL of THF and drying in a vacuum oven at 10 ° C to 60 ° C for 1 hour to 12 hours, Method for producing a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs. According to claim 1,
In step (4), the surface-modified graphite nanofibers and graphene oxide are reacted at a temperature range of 10 ° C to 70 ° C for 1 hour to 4 hours, manufacturing a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs. method. According to claim 1,
In step (5), the graphene oxide/graphite nanofiber composite was washed with 100 mL to 500 mL of ethanol and 100 mL to 500 mL of distilled water for 1 hour to 4 hours, and then washed in a vacuum oven at a temperature range of 10 ° C to 60 ° C for 1 hour to 500 mL. Drying for 12 hours, manufacturing method of carbon fiber reinforced epoxy composite material reinforced with GO-GNFs. According to claim 1,
In step (6), 0.3% to 1.0% by weight of the graphene oxide/graphite nanofiber composite was added to 50mL to 200mL of acetone (C ₃ H ₆ O) relative to 100% by weight of the epoxy resin, and then 40 °C at 10 °C. After ultrasonic treatment is carried out for 1 hour to 2 hours at a temperature range of ℃, the epoxy resin is added to the reaction mixture, and then heated and maintained at a temperature range of 30 ℃ to 65 ℃, followed by stirring for 1 hour to 4 hours, GO - Manufacturing method of carbon fiber reinforced epoxy composite material reinforced with GNFs. According to claim 1,
In step (7), the graphene oxide/graphite nanofiber composite and the organic solvent acetone in the epoxy resin are removed for 4 to 10 hours in the temperature range of 100 ° C to 150 ° C for 4 hours to 10 hours to stabilize, reinforced with GO-GNFs. Manufacturing method of carbon fiber reinforced epoxy composite material. According to claim 1,
In step (8), DDM (4,4'-diaminodiphenylmethane) as a curing agent is added in an equivalent ratio to the epoxy resin to the mixture of the stabilized graphene oxide/graphite nanofiber composite and the epoxy resin, and the temperature ranges from 20 ° C to 70 ° C. Method for producing a carbon fiber reinforced epoxy composite material reinforced with GO-GNFs, which is reacted for 1 hour to 5 hours with According to claim 1,
In step (9), the mixture of the graphene oxide/graphite nanofiber composite, the epoxy resin, and the curing agent is stabilized by removing bubbles in a vacuum oven at a temperature range of 10 ° C to 60 ° C for 1 hour to 3 hours under reduced pressure, GO. - Manufacturing method of carbon fiber reinforced epoxy composite material reinforced with GNFs. According to claim 1,
In the above step (10), the mixture of the stabilized graphene oxide/graphite nanofiber composite, epoxy resin and curing agent and carbon fibers are manually impregnated into the mold, and then hot press in the temperature range of 60 ° C to 90 ° C for 1 hour to 2 hours. Preparation of carbon fiber reinforced epoxy composites reinforced with GO-GNFs, curing time, followed by curing at a temperature range of 90 ° C to 125 ° C for 1 hour to 2 hours, followed by curing at a temperature range of 140 ° C to 170 ° C for 1 hour to 2 hours method.

Images