KR101189153B1 - Method of manufacturing of carbon fibers reinforced composites improved mechanical interface strength - Google Patents

Abstract

The present invention relates to a method for producing a carbon fiber reinforced composite having enhanced mechanical interfacial strength by improving the interfacial bonding force with a thermoplastic matrix by using a carbon fiber sized with a sizing agent as a reinforcing agent.

The method according to the present invention can produce a carbon fiber reinforced composite having a high mechanical interface strength by sizing the carbon fiber to improve the handleability of the carbon fiber and at the same time maximize the interfacial bonding force with the matrix.

Carbon Fiber Reinforced Composites, Sizing, Interfacial Strength, Thermoplastic, Nylon

Description

Method of manufacturing of carbon fibers reinforced composites improved mechanical interface strength}

The present invention relates to a method for manufacturing a carbon fiber reinforced composite having enhanced mechanical interfacial strength, and more particularly, by using a carbon fiber sizing treated as a sizing agent as a reinforcing agent, the interfacial bonding strength with the thermoplastic matrix is improved, thereby enhancing the mechanical interfacial strength. It relates to a method for producing a carbon fiber reinforced composite material.

Carbon fibers and carbon fibers-reinforced composites are not only spotlighted as alternative materials for many industrial machinery parts based on metals, but also in automobiles, aerospace, electrical and electronics, machinery, ships and civil engineering. It is expected to be a key material in future high-tech industries such as medical and medical field.

In addition, it is a material with high specific strength, light weight, fatigue resistance, chemical resistance, and high elastic modulus, and also requires high strength such as bearings, gears and cams, and transportation equipment such as automobile bodies, and sporting goods. It is a promising new material used in earnest.

Carbon fiber has excellent properties such as high strength, high elasticity, high thermal properties, and high conductivity, and can be used as an internal reinforcing agent for carbon fiber reinforced composites. The final mechanical properties of the carbon fiber reinforced composites depend largely on the physical properties of the carbon fiber and the matrix itself, which are used as reinforcing agents, but also on the bonding phenomenon at the interface where the fiber and matrix meet.

Conventional carbon fiber-reinforced composite material is not easy to match the surface characteristics of the carbon fiber and the resin because the thermosetting resin was used as a matrix, even if the composite material produced a phenomenon that the mechanical properties are poor.

Accordingly, the present inventors treated the carbon fiber with a sizing agent to improve the interfacial bonding force between the carbon fiber and the thermosetting matrix resin to prepare a carbon fiber reinforced composite having a high mechanical interface strength and successfully completed the present invention.

As a result, the main object of the present invention is to provide a method for producing a carbon fiber reinforced composite having enhanced mechanical interfacial strength by improving the interfacial bonding force with the thermoplastic matrix by using a carbon fiber sized with a sizing agent as a reinforcing agent.

In order to achieve the above object, the present invention provides a method for producing a carbon fiber-reinforced composite having an enhanced mechanical interfacial strength comprising the step of sizing the carbon fiber in the sizing agent.

In the present invention, the sizing agent is an amino functional silane as a main component, for example, 3-aminopropyltriethoxysilane, 3-aminopropylmethoxydiethoxysilane, aminopropylmethoxydimethoxy Methoxysilane (Aminopropylmethoxydimethoxysilane), aminoethylaminopropyltrimethoxysilane (3- (2-Aminoethyl) aminopropyl] trimethoxysilane), and the like; Sulfur functional silanes such as bis (triethoxysilylpropyl) tetrasulfide (Bis (3- (triethoxysilyl) propyl) tetrasulfide), mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane ( Mercaptopropyltriethoxysilane) and the like; Epoxy functional silanes, for example, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, glycidoxypropylmethyldiethoxysilane, glycidoxypropylmethyl Dimethoxysilane (Glycidoxypropylmethlydimethoxysilane) and the like; It is preferable to use at least one member selected from the group consisting of vinyl functional silanes such as vinyltrimethoxysilane, vinyltriethoxysilane, and the like.

Further, the carbon fiber may be obtained from any raw material such as pitch, rayon or polyacrylonitrile, or may be any of high strength type (low modulus carbon fiber), used elastic carbon fiber, or ultra high elastic carbon fiber. However, the present invention is not limited to the kind of carbon fiber.

In addition, the sizing bath exposure time of the carbon fiber is preferably 10 seconds to 60 minutes. In less than 10 seconds, the reaction time is too short, so the amount of sizing on the surface of the carbon fiber is not preferable, and if it exceeds 60 minutes, the film is damaged and difficult to use as a reinforcing agent.

In addition, the carbon fiber content in the finally produced composite material is suitable for 10 to 50%. If the content of the carbon fiber is less than 10%, it is difficult to obtain high mechanical properties, and if the content of the carbon fiber exceeds 50%, the amount of the matrix is less than that of the carbon fiber, and thus the physical properties are deteriorated.

In addition, the matrix resin usable in the present invention is preferably a thermoplastic resin, more preferably polyolefin resin, polyamide, acrylic (co) polymer, polyalkylene terephthalate, polycarbonate and the like, most preferably Polyethylene, polypropylene, polyamide-6 (nylon-6), polyamide-6,6 (nylon-6,6), polyamide-6,10 (nylon-6,10), polyamide-6,12 (Nylon-6,12), an acrylonitrile-styrene copolymer, and at least 1 sort (s) chosen from a polycarbonate are preferable.

In addition, in the present invention, the pressure of the heating press when manufacturing the carbon fiber reinforced composite is preferably 2.0 to 10.0 MPa. If it is less than 2.0 MPa, pores are generated inside the composite material, which is not preferable because of deterioration of physical properties.

Such carbon fiber-reinforced composite materials can be generally adopted a method generally performed. For example, a thickening resin method used in a hot melt method, a solvent industry, a syrup method or a sheet mold compound (SMC), etc. is possible, and the method of blending the carbon fiber and the matrix resin treated with the sizing agent according to the present invention is particularly limited. You don't have to.

In addition, in the present invention, the temperature of the heating press is preferably 200 to 265 ° C. in manufacturing the carbon fiber reinforced composite material. If the resin used as a matrix is less than 200 ℃ is difficult to produce a composite material, and if it exceeds 265 ℃ it is preferable to proceed in the above temperature range because the phenomenon that the matrix resin deteriorates occurs.

In addition, the carbon fiber-reinforced composite of the present invention further includes a dispersing agent, a heat stabilizer and / or a weathering agent, etc. which are usually used in the production of carbon fiber-reinforced composites to the extent that the composite of the present invention does not impair the desired properties. can do.

The present invention has the effect of providing a method for producing a carbon fiber reinforced composite having excellent mechanical properties.

The method according to the present invention can produce a carbon fiber reinforced composite having a high mechanical interface strength by sizing the carbon fiber to improve the handleability of the carbon fiber and at the same time maximize the interfacial bonding force with the matrix.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these examples are for illustrative purposes only and that the scope of the present invention is not construed as being limited by these examples.

Measurement Example 1 Measurement of Mechanical Interfacial Strength of Carbon Fiber-Nylon Composite

In order to measure the mechanical interfacial strength of the carbon fiber-nylon composite prepared in the present invention, ILSS, K _IC obtained from the three-point bending test and G _IC obtained from the tensile test were measured and discussed. At this time, K _IC is using Instron # 1125 tester (LR5K plus, Lloyd, England) in accordance with ASTM E399, span-to-depth ratio 4: 1, cross head speed 1 mm At a rate of / min, G _IC was measured at a tensile rate of 2 mm / min by the Double Cantilever Beam method according to ASTM D5528.

Measurement Example 2 Surface Structure and Characterization of Carbon Fiber-Nylon Composite

In order to observe the surface structure of the carbon fiber-nylon composite prepared in the present invention, a scanning electron microscope (SEM; S-4200, HITACHI, JAPAN) was used.

Example 1 Preparation of Carbon Fiber-Nylon Composite (1)

Carbon fiber used in the present invention is a polyacrylonitrile (PAN) -based high-strength carbon fiber (TC-3K-36) produced by Formosa Platic Co., 0.1 M HNO ₃ to remove impurities on the surface before sizing Pretreated for 30 minutes and then used.

In addition, in order to improve the interfacial bonding force between nylon and carbon fiber, 10% by weight of aminopropylmethoxydiethoxysilane in amino functional silane was used, and the pretreated carbon fiber was sized for 20 minutes. As it was weak, it was dried for 24 hours in a vacuum oven at 80 ℃ and kept sealed.

In addition, the carbon fiber content of the carbon fiber-nylon composite material is 10% by weight, and after mixing for 10 minutes at 60 rpm using a nylon-6 and an internal mixer, the specimen for measuring the physical properties using a heat press The composition was sufficiently dissolved at 220 ° C. and then pressurized at a pressure of 2.0 MPa for 30 minutes.

Example 2 Preparation of Carbon Fiber-Nylon Composites (2)

Performing the same process as in Example 1, but sizing treatment for 60 minutes using 10% by weight of aminopropyl methoxy diethoxysilane in the amino functional silane as a sizing agent, the content of the carbon fiber when mixing nylon and carbon fiber It was 50 weight%.

In addition, the specimen was prepared at a pressure of 10.0 MPa after sufficiently dissolving the composition at 265 ℃ using a heating press.

Example 3 Preparation of Carbon Fiber-Nylon Composites (3)

Performing the same process as in Example 1, but was sizing treatment for 40 minutes using 10% by weight of aminopropyl methoxy diethoxysilane in the amino functional silane as a sizing agent, the content of the carbon fiber 50 when mixing nylon and carbon fiber The sample was prepared by weight, and the specimen was prepared at a pressure of 5.0 MPa after sufficiently dissolving the composition at 245 ° C. using a heating press.

Example 4 Preparation of Carbon Fiber-Nylon Composites (4)

Performed in the same process as in Example 1, but was sizing treatment for 20 minutes using 10% by weight of bis (triethoxysilylpropyl) tetrasulfide of sulfur functional silane as a sizing agent, the content of carbon fiber when nylon and carbon fiber mixed To 10% by weight, the specimen was prepared using a pressure of 2.0 MPa after sufficiently dissolving the composition at 220 ℃ using a heating press.

Example 5 Preparation of Carbon Fiber-Nylon Composites (5)

Performing the same process as in Example 1, but was sizing treatment for 60 minutes using 10% by weight of bis (triethoxysilylpropyl) tetrasulfide of sulfur functional silane as a sizing agent, the content of carbon fiber when nylon and carbon fiber mixed To 50% by weight, the specimen was prepared by using a heating press at 265 ℃ sufficiently dissolved the composition at a pressure of 10.0 MPa.

Example 6 Preparation of Carbon Fiber-Nylon Composites (6)

Performing the same process as in Example 1, but was sizing treatment for 40 minutes using 10% by weight of bis (triethoxysilylpropyl) tetrasulfide of sulfur functional silane as a sizing agent, the content of carbon fiber when mixing nylon and carbon fiber Was 25% by weight, and the specimen was prepared at a pressure of 5.0 MPa after the composition was sufficiently dissolved at 245 ° C. using a heating press.

Example 7 Preparation of Carbon Fiber-Nylon Composites (7)

The same process as in Example 1 was performed, but the sizing treatment was performed for 10 minutes using 10% by weight of glycidoxypropyltrimethoxysilane in the epoxy functional silane as a sizing agent. By weight, the specimen was prepared at a pressure of 2.0 MPa after sufficiently dissolving the composition at 220 ℃ using a heating press.

Example 8 Preparation of Carbon Fiber-Nylon Composites (8)

The same process as in Example 1 was carried out, but sizing treatment was performed for 60 minutes using 10% by weight of glycidoxypropyltrimethoxysilane in the epoxy functional silane as a sizing agent. The sample was prepared by weight, and the specimen was prepared at a pressure of 10.0 MPa after sufficiently dissolving the composition at 265 ° C. using a heating press.

Example 9 Preparation of Carbon Fiber-Nylon Composites (9)

The same process as in Example 1 was performed, but the sizing treatment was performed for 10 minutes using 10% by weight of glycidoxypropyltrimethoxysilane in the epoxy functional silane as a sizing agent. The sample was prepared by weight, and the specimen was prepared at a pressure of 5.0 MPa after sufficiently dissolving the composition at 245 ° C. using a heating press.

Example 10 Preparation of Carbon Fiber-Nylon Composites (10)

The same process as in Example 1 was performed, but the sizing treatment was performed for 10 minutes using 10% by weight of vinyltrimethoxysilane in the vinyl functional silane as a sizing agent, and the carbon fiber content was 10% by weight when the nylon and carbon fiber were mixed. And, the specimen was prepared at a pressure of 2.0 MPa after sufficiently dissolving the composition at 220 ℃ using a heating press.

Example 11 Preparation of Carbon Fiber-Nylon Composites (11)

The same process as in Example 1 was carried out, but sizing treatment was performed for 60 minutes using 10% by weight of glycidoxypropyltrimethoxysilane in the epoxy functional silane as a sizing agent. The sample was prepared by weight, and the specimen was prepared at a pressure of 10.0 MPa after sufficiently dissolving the composition at 265 ° C. using a heating press.

Example 12 Preparation of Carbon Fiber-Nylon Composites (12)

The same process as in Example 1 was performed, but the sizing treatment was performed for 10 minutes using 10% by weight of glycidoxypropyltrimethoxysilane in the epoxy functional silane as a sizing agent. The sample was prepared by weight, and the specimen was prepared at a pressure of 5.0 MPa after sufficiently dissolving the composition at 245 ° C. using a heating press.

Comparative Example 1

Perform the same process as in Example 1, but did not use a sizing agent, the content of the carbon fiber is 60% by weight when the nylon and carbon fibers are mixed, the specimen is sufficiently heated the composition at 300 ℃ using a heating press After melting, it was prepared at a pressure of 13.0 MPa.

Example 13. Preparation of Carbon Fiber-Nylon Composite (13)

A carbon fiber-nylon composite was prepared by following the same process as Example 1 except using 10% by weight of aminopropyltriethoxysilane in the amino functional silane as a sizing agent.

Example 14 Preparation of Carbon Fiber-Nylon Composites (14)

A carbon fiber-nylon composite was prepared by following the same process as Example 1 except using 10% by weight of aminopropylmethoxydimethoxysilane in the amino functional silane as a sizing agent.

Example 15 Preparation of Carbon Fiber-Nylon Composites (15)

A carbon fiber-nylon composite was prepared by following the same process as Example 1 except using 10% by weight of aminoethylaminopropyltrimethoxysilane in the amino functional silane as a sizing agent.

Example 16. Preparation of Carbon Fiber-Nylon Composites (16)

The same process as in Example 1 was performed, but a carbon fiber-nylon composite was prepared using 10 wt% of mercaptopropyltrimethoxysilane in the sulfur functional silane as a sizing agent.

Example 17. Preparation of Carbon Fiber-Nylon Composites (17)

The same process as in Example 1 was performed, but a carbon fiber-nylon composite was prepared using 10 wt% of mercaptopropyltriethoxysilane in sulfur functional silane as a sizing agent.

Example 18. Preparation of Carbon Fiber-Nylon Composites (18)

A carbon fiber-nylon composite was prepared by following the same process as Example 1 except using 10% by weight of glycidoxypropyltriethoxysilane in an epoxy functional silane as a sizing agent.

Example 19. Preparation of Carbon Fiber-Nylon Composites (19)

A carbon fiber-nylon composite was prepared by following the same process as Example 1 except using 10% by weight of glycidoxypropylmethyldiethoxysilane in the epoxy functional silane as a sizing agent.

Example 20 Preparation of Carbon Fiber-Nylon Composites (20)

A carbon fiber-nylon composite material was prepared by following the same process as Example 1 except using 10% by weight of glycidoxypropylmethoxydimethoxysilane in an epoxy functional silane as a sizing agent.

Example 21. Preparation of Carbon Fiber-Nylon Composites (21)

A carbon fiber-nylon composite was prepared by following the same process as Example 1 except using 10% by weight of vinyltriethoxysilane in the vanyl functional silane as a sizing agent.

Comparative Example 2

Following the same process as in Example 1, a carbon fiber-nylon composite was prepared without using a sizing agent.

Table 1 shows the results of measuring the mechanical interfacial strength of the carbon fiber-nylon composites prepared in Examples 1 to 12 and Comparative Examples, Table 2 is the carbon fiber of Examples 13 to 21 and Comparative Example 2 Mechanical interface strength results of nylon composites are shown.

As shown in Tables 1 and 2, the sizing treatment resulted in high mechanical interfacial strength of the carbon fiber-nylon composite with increased interfacial bonding force. However, when the sizing treatment time, the carbon fiber content, the pressure and temperature of the heating press during the manufacture of the composite were excessive, the mechanical interface strength decreased.

Therefore, when the appropriate conditions are given, it can be confirmed that a carbon fiber reinforced composite obtained by applying various materials with high mechanical interfacial strength.

division Sizing agent Sizing
time
(minute) Carbon fiber
content
(weight%) Heating press temperature
(℃) Heating press pressure
(MPa) Mechanical
Interface strength Example 1 Aminopropylmethoxydiethoxysilane 20 10 220  2.0 ILSS 2.22 K _IC 3.11 G _IC 6.54 Example 2 60 50 265 10.0 ILSS 2.71 K _IC 3.45 G _IC 7.01 Example 3 40 25 245 5.0 ILSS 2.58 K _IC 3.30 G _IC 6.85 Example 4 Bis (triethoxysilylpropyl) tetrasulfide 20 10 220 2.0 ILSS 1.51 K _IC 2.11 G _IC 3.12 Example 5 60 50 265 10.0 ILSS 1.92 K _IC 2.61 G _IC 3.70 Example 6 40 25 245 5.0 ILSS 1.64 K _IC 3.23 G _IC 3.41 Example 7 Glycidoxypropyltrimethoxysilane 20 10 220 2.0 ILSS 1.80 K _IC 2.61 G _IC 5.12 Example 8 60 50 265 10.0 ILSS 2.15 K _IC 3.12 G _IC 5.91 Example 9 40 25 245 5.0 ILSS 2.09 K _IC 2.96 G _IC 5.55 Example 10 Vinyltrimethoxysilane 20 10 220 2.0 ILSS 1.51 K _IC 2.12 G _IC 3.42 Example 11 60 50 265 10.0 ILSS 1.73 K _IC 2.51 G _IC 3.84 Example 12 40 25 245 5.0 ILSS 1.71 K _IC 2.43 G _IC 3.72 Comparative Example 1 - - 60 300 13.0 ILSS 1.12 K _IC 1.72 G _IC 2.03

division Sizing agent Mechanical interfacial strength Example 2 Aminopropylmethoxydiethoxysilane ILSS 2.22 K _IC 3.11 G _IC 6.54 Example 13 Aminopropyltriethoxysilane ILSS 2.18 K _IC 3.07 G _IC 6.32 Example 14 Aminopropylmethoxydimethoxysilane ILSS 2.24 K _IC 3.35 G _IC 6.67 Example 15 Aminoethylaminopropyltrimethoxysilane ILSS 2.32 K _IC 3.42 G _IC 6.71 Example 4 Bis (triethoxysilylpropyl) tetrasulfide ILSS 1.51 K _IC 2.11 G _IC 3.12 Example 16 Mercaptopropyltrimethoxysilane ILSS 1.46 K _IC 2.08 G _IC 3.07 Example 17 Mercaptopropyltriethoxysilane ILSS 1.61 K _IC 2.13 G _IC 3.09 Example 7 Glycidoxypropyltrimethoxysilane ILSS 1.80 K _IC 2.61 G _IC 5.12 Example 18 Glycidoxypropyltriethoxysilane ILSS 1.76 K _IC 2.56 G _IC 5.04 Example 19 Glycidoxypropylmethyldiethoxysilane ILSS 1.82 K _IC 2.66 G _IC 5.15 Example 20 Glycidoxypropylmethoxydimethoxysilane ILSS 1.90 K _IC 2.82 G _IC 5.24 Example 10 Vinyltrimethoxysilane ILSS 1.51 K _IC 2.12 G _IC 3.42 Example 21 Vinyltriethoxysilane ILSS 1.53 K _IC 2.08 G _IC 3.34 Comparative Example 2 - ILSS 1.08 K _IC 1.34 G _IC 1.83

As described above, specific portions of the contents of the present invention have been described in detail, and for those skilled in the art, these specific techniques are merely preferred embodiments, and the scope of the present invention is not limited thereto. Will be obvious. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

1 is an SEM image of a carbon fiber reinforced composite prepared using aminopropylmethoxydiethoxysilane as a sizing agent according to one embodiment of the present invention.

2 is a SEM photograph of a carbon fiber reinforced composite prepared using bis (triethoxysilylpropyl) tetrasulfide as a sizing agent according to one embodiment of the present invention.

3 is an SEM image of a carbon fiber reinforced composite prepared using glycidoxypropyl trimethoxysilane as a sizing agent according to one embodiment of the present invention.

Claims (7)

In the carbon fiber reinforced composite manufacturing method comprising the step of sizing the carbon fiber in the sizing agent, (1) pretreatment of the carbon fiber with 0.1 M HNO ₃ for 30 minutes to remove impurities on the surface before sizing; (2) sizing for 10 seconds to 60 minutes using the carbon fiber pretreated in step (1) using one selected from amino functional silane, sulfur functional silane, epoxy functional silane and vinyl functional silane as a sizing agent; (3) mixing the carbon fiber and nylon so that the carbon fiber sized by the step (2) is contained in the carbon fiber-nylon composite 10 to 50% by weight; And (4) heating and pressurizing the carbon fiber-nylon composite mixed by the step (3) using a heating press at a temperature of 200 to 265 ° C. and a pressure of 2.0 to 10.0 MPa. . The method of claim 1, The sizing agent used in step (2) is 3-aminopropyltriethoxysilane, 3-Aminopropylmethoxydiethoxysilane, aminopropylmethoxydimethoxysilane, aminoethyl Aminopropyltrimethoxysilane (3- (2-Aminoethyl) aminopropyl] trimethoxysilane), bis (triethoxysilylpropyl) tetrasulfide (Bis (3- (triethoxysilyl) propyl) tetrasulfide), mercaptopropyltrimethoxysilane ( Mercaptopropyltrimethoxysilane), Mercaptopropyltriethoxysilane, Glycidoxypropyltrimethoxysilane, Glycidoxypropyltriethoxysilane, Glycidoxypropyltriethoxysilane, Glycidoxypropylmethyldiethoxysilane Glycidoxypropylmethlydimethoxysilane, bi Trimethoxysilane (Vinyltrimethoxysilane), carbon fibers, characterized in that the vinyl-tree is one of a silane (Vinyltriethoxysilane) reinforced composite material manufacturing method. delete delete delete delete delete

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