KR20220008533A - Basalt fiber-reinforced epoxy composites with graphene oxide and method for manufacturing the same - Google Patents

Abstract

The present specification discloses a basalt fiber-reinforced epoxy composite material into which graphene oxide is introduced and a method for manufacturing the same. A technology disclosed in the specification has the effect of providing a basalt fiber-reinforced epoxy composite material with improved interfacial and mechanical strength by introducing graphene oxide into the basalt fiber-reinforced epoxy composite material.

Description

Graphene oxide-introduced basalt fiber-reinforced epoxy composite material and manufacturing method thereof

The present specification discloses a basalt fiber-reinforced epoxy composite material into which graphene oxide is introduced and a method for manufacturing the same.

Epoxy, which has two or more epoxy groups (C-O-C) in its molecule, can be made into hard, insoluble fiber-reinforced polymer composites (FRP) materials by curing with basalt fibers. Because of the high tensile modulus of epoxy, adhesive properties, chemical resistance, structural stability, etc., and the high strength, low specific gravity, and strong chemical resistance of basalt fibers, polymer composites reinforced with basalt fibers are emerging as a good alternative. , aerospace, ships, auto parts, marine equipment, and electric and electronic industries. However, basalt fibers exhibit low interfacial adhesion inside the epoxy matrix due to their structural defects and chemically inert surface. These problems reduce the interfacial and mechanical strength, and have many limitations in application to actual industrial fields.

KR 10-2011-0051575 A

In one aspect, an object of the present specification is to provide a basalt fiber-reinforced epoxy composite material with improved interfacial and mechanical strength.

In another aspect, an object of the present specification is to provide a method of manufacturing the basalt fiber-reinforced epoxy composite material.

In one aspect, the present specification is an epoxy resin; oxides having an oxygen functional group and containing carbon; And it provides an epoxy composite material comprising a basalt fiber.

In an exemplary embodiment, the oxide may include graphene oxide.

In an exemplary embodiment, the composite material may include 1 to 5 parts by weight of oxide based on 100 parts by weight of the epoxy resin.

In an exemplary embodiment, the composite material may include 40 to 60 parts by weight of basalt fibers based on 100 parts by weight of the epoxy resin.

In an exemplary embodiment, the composite material may have an interlaminar shear strength of 30 MPa or more when measured according to ASTM D-2344.

In an exemplary embodiment, the composite material may have a fracture toughness of ^{40 MPa.m 1/2 or more when measured according to ASTM E399.}

In another aspect, the present specification provides a method for manufacturing the epoxy composite material, 1) preparing a primary mixture by mixing an epoxy resin and an oxide having an oxygen functional group and containing carbon with an organic solvent; 2) preparing a secondary mixture by adding a curing agent to the primary mixture; and 3) impregnating the basalt fiber in the secondary mixture and then curing the epoxy composite material.

In an exemplary embodiment, the organic solvent in step 1) may include acetone.

In an exemplary embodiment, step 1) may include adding an oxide having an oxygen functional group and containing carbon to an organic solvent, performing ultrasonic treatment, and then adding an epoxy resin and heat treatment.

In an exemplary embodiment, the ultrasonic treatment may be performed at 10 to 50 °C, and the heat treatment may be performed at 30 to 70 °C.

In an exemplary embodiment, step 1) may further include stabilizing the first mixture by removing the organic solvent after preparing the first mixture.

In an exemplary embodiment, the curing agent in step 2) may include 4,4'-diaminodiphenylmethane (4,4'-diaminodiphenylmethane).

In an exemplary embodiment, step 2) may further include stabilizing the secondary mixture by removing air bubbles after preparing the secondary mixture.

In an exemplary embodiment, the curing in step 3) may be a gradual curing by increasing the temperature step by step from 60 to 170 ℃.

In an exemplary embodiment, the curing in step 3) may be sequentially primary curing at 60 to 90°C, secondary curing at more than 90°C to 125°C, and tertiary curing at 140 to 170°C.

In one aspect, the technology disclosed herein has the effect of providing a basalt fiber-reinforced epoxy composite material with improved interfacial and mechanical strength.

In another aspect, the technology disclosed herein has the effect of providing a method of manufacturing the basalt fiber reinforced epoxy composite material.

In another aspect, the technology disclosed herein uses graphene oxide as a filler and adds it to an epoxy resin, whereby the oxygen functional group of graphene oxide leads to strong interfacial adhesion with an epoxy resin that is easy to process into a thermosetting resin, It has the effect of providing a basalt fiber-reinforced epoxy composite material with significantly improved thermal properties and mechanical strength.

1 is a graph comparing the surface energy of the graphene oxide-added basalt fiber-reinforced epoxy composite material according to an embodiment and the basalt fiber-reinforced epoxy composite material according to a comparative example.
2 is a graph comparing the interlaminar shear strength (ILSS) of the graphene oxide-added basalt fiber-reinforced epoxy composite material according to an embodiment and the basalt fiber-reinforced epoxy composite material according to a comparative example.
3 is a graph comparing the fracture toughness (KIC) of the graphene oxide-added basalt fiber-reinforced epoxy composite material according to an embodiment and the basalt fiber-reinforced epoxy composite material according to a comparative example.
4 is a SEM photograph of the fracture surface after measuring the fracture toughness of the graphene oxide-added basalt fiber-reinforced epoxy composite material according to an embodiment and the basalt fiber-reinforced epoxy composite material according to a comparative example.

Hereinafter, the present specification will be described in detail.

In one aspect, the present specification is an epoxy resin; oxides having an oxygen functional group and containing carbon; And it provides an epoxy composite material comprising a basalt fiber.

In an exemplary embodiment, the oxide may include graphene oxide. Oxygen-containing functional groups such as functional groups -OH, -C=O, and -COOH of graphene oxide may improve interfacial adhesion in the epoxy matrix. In particular, graphene oxide provides the functionality to deliver excellent nano-scale properties to the micro-scale. The basalt fiber-reinforced epoxy composite material according to the present specification greatly improves the interfacial interaction and dispersion force of the basalt fiber with the epoxy resin by introducing graphene oxide made of a 2D material, and has stronger interfacial strength and mechanical strength compared to the conventional basalt fiber-reinforced epoxy composite material. It has the effect of showing characteristics.

In an exemplary embodiment, the graphene oxide may be prepared by a Hummers method.

In an exemplary embodiment, the graphene oxide may be prepared by the following method: 3 g of graphite _{is mixed with 360 mL of sulfuric acid (H 2} SO ₄ ) stock solution and _{40 mL of phosphoric acid (H 3} PO ₄ ) stock solution. After putting in an acidic solution, _{18 g of potassium permanganate (KMnO 4} ) is slowly added under an ice water bath. After completely dissolving KMnO ₄ , the temperature of the solution is maintained by heating in a temperature range of 40 to 50°C. It may be desirable to react for 12 to 24 hours. After the reaction is completed, the solution is cooled slowly to room temperature, and then slowly poured into a glass glass filled with ice while stirring. _{Slowly add hydrogen peroxide (H 2} O ₂ ) until all the ice is dissolved and the temperature of the solution is kept low, until no bubbles are formed. Thereafter, after washing using distilled water, 10% hydrochloric acid solution, and ethanol, neutralization and washing are performed using distilled water until the pH of the solution reaches 6 to 7. Thereafter, the neutralized graphene oxide solution is freeze-dried (temperature -50 to -80° C., pressure 0.065 bar) to obtain graphene oxide.

In an exemplary embodiment, the composite material may include 1 to 5 parts by weight of oxide based on 100 parts by weight of the epoxy resin. In another exemplary embodiment, it may be preferable for the composite material to include 2 to 4 parts by weight of oxide based on 100 parts by weight of the epoxy resin in terms of interfacial and mechanical strength improvement.

In an exemplary embodiment, the composite material may include 40 to 60 parts by weight of basalt fibers based on 100 parts by weight of the epoxy resin.

In an exemplary embodiment, the composite material may have an interlaminar shear strength of 30 MPa or more, or 35 MPa or more, or 35 to 45 MPa as measured according to ASTM D-2344.

In an exemplary embodiment, the composite material has a fracture toughness of ^{40 MPa.m 1/2} or more, or 55 MPa.m ^1/2 or more, or 55 to 70 MPa.m ^{1/2 as measured according to ASTM E399.} may have

In another aspect, the present specification provides a method for manufacturing the epoxy composite material, 1) preparing a primary mixture by mixing an epoxy resin and an oxide having an oxygen functional group and containing carbon with an organic solvent; 2) preparing a secondary mixture by adding a curing agent to the primary mixture; and 3) impregnating the basalt fiber in the secondary mixture and then curing the epoxy composite material.

In an exemplary embodiment, the oxide in step 1) may be mixed in an amount of 1 to 5 parts by weight based on 100 parts by weight of the epoxy resin. In another exemplary embodiment, in step 1), it may be preferable to mix 2 to 4 parts by weight of the oxide based on 100 parts by weight of the epoxy resin to improve the interface and mechanical strength.

In an exemplary embodiment, the organic solvent in step 1) may include acetone.

In an exemplary embodiment, step 1) may include adding an oxide having an oxygen functional group and containing carbon to an organic solvent, performing ultrasonic treatment, and then adding an epoxy resin and heat treatment. Thereby, a stable dispersion can be obtained.

In an exemplary embodiment, the ultrasonic treatment may be preferably performed at 10 to 50 °C.

In an exemplary embodiment, the ultrasonic treatment may be preferably performed for 1 to 2 hours.

In an exemplary embodiment, the heat treatment may be preferably carried out at 30 to 70 ℃.

In an exemplary embodiment, the heat treatment may preferably include stirring the mixture for 1 to 4 hours.

In an exemplary embodiment, step 1) may further include stabilizing the first mixture by removing the organic solvent after preparing the first mixture.

In an exemplary embodiment, the stabilizing step of the first mixture may be to remove the organic solvent by heat treatment at 100 to 150 ℃.

In an exemplary embodiment, the stabilizing step of the first mixture may be to remove the organic solvent for 4 to 10 hours.

In an exemplary embodiment, it may be preferable to add the curing agent after removing the organic solvent of the first mixture in step 2).

In an exemplary embodiment, the curing agent in step 2) may include 4,4'-diaminodiphenylmethane (4,4'-diaminodiphenylmethane).

In an exemplary embodiment, the curing agent in step 2) may be added in an amount of 34 to 36 parts by weight based on 100 parts by weight of the epoxy resin.

In an exemplary embodiment, step 2) may be to prepare a secondary mixture by adding a curing agent and then reacting at 20 to 70°C.

In an exemplary embodiment, step 2) may be to prepare a secondary mixture by reacting for 1 to 5 hours after adding the curing agent.

In an exemplary embodiment, step 2) may further include stabilizing the secondary mixture by removing air bubbles after preparing the secondary mixture. By removing air bubbles, it is possible to prevent the interface and mechanical strength of the epoxy composite from being deteriorated.

In an exemplary embodiment, the stabilizing step of the secondary mixture may be stabilizing in a vacuum oven.

In an exemplary embodiment, the stabilizing step of the secondary mixture may be to remove air bubbles at 10 to 60 °C under reduced pressure.

In an exemplary embodiment, the stabilizing step of the secondary mixture may be to remove air bubbles for 1 to 3 hours under reduced pressure.

In an exemplary embodiment, it may be preferable to add the basalt fiber in step 3) after removing air bubbles in the secondary mixture.

In an exemplary embodiment, the basalt fiber in step 3) may be added in an amount of 40 to 60 parts by weight based on 100 parts by weight of the epoxy resin.

In an exemplary embodiment, the curing in step 3) may be carried out at 60 to 170 ℃, or 110 to 170 ℃. Accordingly, it is possible to prevent a problem that the curing temperature may not be completely cured because the curing temperature is too low, and it is possible to prevent the problem that the curing temperature is too high to cause deterioration of physical properties.

In an exemplary embodiment, the curing in step 3) may be performed for 3 to 6 hours.

In an exemplary embodiment, the curing in step 3) may be a gradual curing by increasing the temperature step by step. By gradually curing with increasing temperature, pores or impregnation are prevented, and the interface and mechanical strength of the epoxy composite material are improved.

In an exemplary embodiment, the curing in step 3) may be a gradual curing by increasing the temperature step by step from 60 to 170 ℃.

In one exemplary embodiment, the curing in step 3) is sequentially primary curing at 60 to 90° C. (stabilization step), secondary curing at more than 90° C. to 125° C. (temporary curing step), and 140 to 170° C. It may be a tertiary curing (curing step) in

In an exemplary embodiment, the primary curing, secondary curing, and tertiary curing may be performed for 1 to 2 hours, respectively.

The method for manufacturing an epoxy composite material according to the present specification is a basalt fiber-reinforced epoxy composite material with significantly improved interface and mechanical strength by introducing an oxide having an oxygen functional group and containing carbon, such as graphene oxide, to the basalt fiber-reinforced epoxy composite material has the effect of

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

Example 1.

1 part by weight of graphene oxide was put in 200 mL of acetone (C ₃ H ₆ O) relative to 100 parts by weight of the epoxy resin, and then dispersed by ultrasonication at a temperature range of 40 to 45° C. for 1 hour. An epoxy resin was added to the mixture, and then heated and maintained at a temperature range of 50 to 55° C. and stirred for 2 hours. Thereafter, the organic solvent was removed at a temperature range of 130 to 140° C. for 5 to 6 hours. 4,4'-diaminodiphenylmethane was added to the remaining graphene oxide and the epoxy resin in an amount of 34 to 36 parts by weight based on 100 parts by weight of the epoxy resin as a curing agent, and reacted at a temperature of 30 to 35° C. for 5 hours. Thereafter, air bubbles were removed in a temperature range of 20 to 25° C. under reduced pressure in a vacuum oven for 1 hour. Then, after manually impregnating the mold with 50 parts by weight of basalt fiber based on 100 parts by weight of the epoxy resin, the first step in a hot press is at a temperature range of 60 to 90° C. for 1-2 hours, and the second step is over 90° C. to 125 A basalt fiber-reinforced epoxy composite material with graphene oxide added thereto was prepared by curing in a total of three steps for 1 to 2 hours at a temperature range of 1 to 2 hours and 3 steps at a temperature of 140 to 170° C. in the temperature range of °C.

Example 2.

An epoxy composite material was prepared in the same manner as in Example 1, but 2 parts by weight of graphene oxide was added to 100 parts by weight of the epoxy resin to prepare a basalt fiber-reinforced epoxy composite material to which graphene oxide was added.

Example 3.

An epoxy composite material was prepared in the same manner as in Example 1, but 3 parts by weight of graphene oxide was added to 100 parts by weight of the epoxy resin to prepare a basalt fiber-reinforced epoxy composite material to which graphene oxide was added.

Example 4.

An epoxy composite material was prepared in the same manner as in Example 1, but 4 parts by weight of graphene oxide was added to 100 parts by weight of the epoxy resin to prepare a basalt fiber-reinforced epoxy composite material to which graphene oxide was added.

Example 5.

An epoxy composite material was prepared in the same manner as in Example 1, but 5 parts by weight of graphene oxide was added to 100 parts by weight of the epoxy resin to prepare a basalt fiber-reinforced epoxy composite material to which graphene oxide was added.

Comparative Example 1.

100 g of the epoxy resin was heated and maintained in a temperature range of 50 to 55° C. and stirred for 2 hours. Then, 4,4'-diaminodiphenylmethane was added to the epoxy resin in an amount of 34 to 36 parts by weight based on 100 parts by weight of the epoxy resin as a curing agent, and reacted at a temperature of 30 to 35° C. for 5 hours. Thereafter, air bubbles were removed in a temperature range of 20 to 25° C. under reduced pressure in a vacuum oven for 1 hour. Then, after manually impregnating the mold with 50 parts by weight of basalt fiber based on 100 parts by weight of the epoxy resin, the first step in a hot press is at a temperature range of 60 to 90° C. for 1-2 hours, and the second step is over 90° C. to 125 A basalt fiber-reinforced epoxy composite material was prepared by curing in a total of 3 steps for 1 to 2 hours at a temperature range of ℃ 1 to 2 hours, 3 steps for 1 to 2 hours at a temperature range of 140 to 170 ℃.

Comparative Example 2.

An epoxy composite material was prepared in the same manner as in Comparative Example 1, but the weight of the epoxy resin was 80 g to prepare a basalt fiber-reinforced epoxy composite material.

Comparative Example 3.

An epoxy composite material was prepared in the same manner as in Comparative Example 1, but the weight of the epoxy resin was 60 g to prepare a basalt fiber-reinforced epoxy composite material.

sample name filler
Kinds filler
content
(weight g) Suzy
content
(weight g) Dispersion
hour
(min) agitation
hour
(min) bubble removal
hour
(min) Hardening
Temperature
(℃) Example 1 graphene
oxide One 100 60 120 60 170 Example 2 graphene
oxide 2 100 60 120 60 170 Example 3 graphene
oxide 3 100 60 120 60 170 Example 4 graphene
oxide 4 100 60 120 60 170 Example 5 graphene
oxide 5 100 60 120 60 170 Comparative Example 1 - - 100 60 120 60 170 Comparative Example 2 - - 80 60 120 60 170 Comparative Example 3 - - 60 60 120 60 170

Measurement Example 1. Surface energy test of epoxy composite material

The surface energy was measured using a Rame-Hart goniometer (Phoenix 300 Plus, SEO Co.) to measure the contact angle of the epoxy composites with respect to three standard wetting liquids (distilled water, diiodomethane, and ethylene glycol).

Measurement Example 2. ILSS Test of Epoxy Composite Materials

The ILSS test was measured by a short-beam three-point bending test method after preparing a specimen for an epoxy composite material according to ASTM D-2344 using a universal testing machine (Lloyd LR5k).

Measurement Example 3. Fracture toughness test of epoxy composite material

The fracture toughness test was measured using a universal testing machine (Lloyd LR5k) to prepare a specimen for an epoxy composite material according to ASTM E399, and then use a 3-point bending test method.

Measurement Example 4. Observation of fracture surface after fracture toughness test of epoxy composite material

It was observed whether the structure of the epoxy composite material was changed after the fracture toughness test using a scanning electron microscope (SEM, SU 8010, Hitachi, Ltd., Japan).

surface energy
(mJ.m ^-2 ) ILSS
(MPa) fracture toughness
(MPa.m ^1/2 ) Example 1 39.2 32.7 ± 5.2 44.5 ± 4.1 Example 2 41.2 39.1 ± 2.1 58.8 ± 0.9 Example 3 43.6 43.8 ± 1.7 67.1 ± 1.1 Example 4 40.8 36.5 ± 1.8 56.2 ± 2.1 Example 5 39.9 34.1 ± 2.4 46.3 ± 1.5 Comparative Example 1 38.4 28.3 ± 3.4 37.1 ± 5.1 Comparative Example 2 37.6 25.6 ± 2.4 32.3 ± 4.8 Comparative Example 3 36.8 23.6 ± 1.6 28.4 ± 2.2

Above, specific parts of the present specification have been described in detail, and for those of ordinary skill in the art, it is clear that these specific techniques are only preferred embodiments, and the scope of the present specification is not limited thereby. something to do. Accordingly, it is intended that the substantial scope of the present specification be defined by the appended claims and their equivalents.

Claims (15)

epoxy resin;
oxides having an oxygen functional group and containing carbon; and
Epoxy composite material containing basalt fibers. The method of claim 1,
The oxide will include graphene oxide, an epoxy composite material. The method of claim 1,
The composite material is an epoxy composite material comprising 1 to 5 parts by weight of an oxide based on 100 parts by weight of the epoxy resin. The method of claim 1,
The composite material is an epoxy composite material comprising 40 to 60 parts by weight of basalt fibers based on 100 parts by weight of the epoxy resin. The method of claim 1,
The composite material will have an interlayer shear strength of 30 MPa or more when measured according to ASTM D-2344, an epoxy composite material. The method of claim 1,
^{The composite material will have a fracture toughness of 40 MPa.m 1/2} or more when measured according to ASTM E399, an epoxy composite material. The method for manufacturing an epoxy composite material according to any one of claims 1 to 6,
1) preparing a primary mixture by mixing an epoxy resin and an oxide having an oxygen functional group and containing carbon with an organic solvent;
2) preparing a secondary mixture by adding a curing agent to the primary mixture; and
3) Method for producing an epoxy composite material comprising the step of impregnating the basalt fiber in the secondary mixture and then curing. 8. The method of claim 7,
In step 1), the organic solvent comprises acetone, the method for producing an epoxy composite material. 8. The method of claim 7,
In the step 1), an oxide having an oxygen functional group and containing carbon is added to an organic solvent, subjected to ultrasonic treatment, and then an epoxy resin is added and heat treatment is performed, the method for producing an epoxy composite material. 10. The method of claim 9,
The ultrasonic treatment is carried out at 10 to 50 ℃, the heat treatment is carried out at 30 to 70 ℃, the method of manufacturing an epoxy composite material. 8. The method of claim 7,
The 1) step further comprises the step of stabilizing the primary mixture by removing the organic solvent after preparing the primary mixture, the method for producing an epoxy composite material. 8. The method of claim 7,
In step 2), the curing agent comprises 4,4'-diaminodiphenylmethane (4,4'-diaminodiphenylmethane), the method for producing an epoxy composite material. 8. The method of claim 7,
The 2) step further comprises the step of stabilizing the secondary mixture by removing air bubbles after preparing the secondary mixture, the method for producing an epoxy composite material. 8. The method of claim 7,
The curing in step 3) is to gradually cure by increasing the temperature step by step at 60 to 170 ℃, the method for producing an epoxy composite material. 15. The method of claim 14,
The curing in step 3) is sequentially primary curing at 60 to 90 ℃, secondary curing at more than 90 ℃ to 125 ℃, and tertiary curing at 140 to 170 ℃, the method of manufacturing an epoxy composite material.

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