KR101197723B1 - Manufacturing process of nickel-plated carbon fibers by non-electroplating method - Google Patents

Abstract

The present invention relates to a method for producing nickel-plated carbon fibers by electroless plating, and more particularly to preparing carbon fibers by electrospinning using polyamide-imide spinning solution, and chemically reducing the surface of the prepared carbon fibers. The present invention relates to a method for manufacturing a highly conductive carbon fiber having improved electrical conductivity by plating with a nickel-phosphorus alloy through a method of electroless plating, and a highly conductive carbon fiber produced thereby.
According to the present invention as described above, the nickel electroless plated carbon fiber manufacturing method is capable of a continuous process, stable processing and at the same time by introducing a uniform and uniform nickel-phosphorus alloy in the carbon fiber surface shape is high It may have conductivity.

Description

MANUFACTURING PROCESS OF NICKEL-PLATED CARBON FIBERS BY NON-ELECTROPLATING METHOD}

The present invention relates to a method for producing nickel-plated carbon fibers by electroless plating, and more particularly to preparing carbon fibers by electrospinning using polyamide-imide spinning solution, and chemically reducing the surface of the prepared carbon fibers. The present invention relates to a method for manufacturing a highly conductive carbon fiber having improved electrical conductivity by plating with a nickel-phosphorus alloy through a method of electroless plating, and a highly conductive carbon fiber produced thereby.

Recently, carbon fiber has been commercially produced and sold as a reinforcing fiber material of high-performance composite materials such as sports and leisure applications, including the aerospace and aviation industries, due to its excellent mechanical and electrical properties.

In particular, the highly conductive carbon fiber has excellent characteristics such as heat resistance, chemical stability, electrical conductivity, electromagnetic shielding, biocompatibility, flexibility, and the like, and thus can be widely applied in various industrial fields. Among them, excellent conductivity is a material of surface heating element and electromagnetic interference shielding, which can be used for the purpose of mutual interference of electromagnetic waves and blocking of electromagnetic waves harmful to human body, and is also active in the application of electrochemical devices as electrode materials. Is going on.

Conventionally, a method of producing a highly conductive carbon fiber by reducing and depositing metal ions from a liquid electrolyte to form a metal film on a plated object is an electroplating method in which electrolytic precipitation is performed by external power to electrochemically oxidize the surface of the fiber, metal salts and solubility. There are a chemical reduction plating method in which metal ions are reduced by electrons released by the oxidation reaction of the reducing agent in a solution in which a reducing agent coexists, and a metal plating in which a metal coating in a solution is substituted and deposited by plating.

Among them, the electroplating method has a disadvantage that the base layer should be a conductor, the thickness is uneven in the surface phenomenon of the base layer due to the influence of the current density, and it is difficult to uniformly plate the complex shape. In addition, the conventional carbon fiber has a disadvantage that it is difficult to apply in the field requiring high electrical conductivity because the electrical conductivity is only 10 ³ ~ 10 ¹ S / cm.

Accordingly, in the present invention, in order to develop carbon fibers having high electrical conductivity, carbon fibers are manufactured by electrospinning, and nickel-phosphorus alloys as well as oxygen functional groups are formed on the surface of carbon fibers manufactured by electroless plating, which is a chemical reduction method. The present invention has been successfully completed by introducing carbon fibers with improved electrical conductivity.

Accordingly, an object of the present invention is to provide a method for producing a highly conductive carbon fiber by improving the electrical conductivity of the carbon fiber by plating with a nickel-phosphorus alloy through the electroless plating method which is a chemical reduction method.

In order to achieve the above object, the present invention provides a method for producing a nickel-plated carbon fiber comprising immersing the carbon fiber in an electroless plating solution containing a nickel salt, a reducing agent and a complexing agent.

According to the present invention as described above, the nickel electroless plated carbon fiber manufacturing method is capable of a continuous process, stable processing and at the same time by introducing a uniform and uniform nickel-phosphorus alloy in the carbon fiber surface shape is high It may have conductivity.

In addition, it is possible to control the conductivity of the carbon fiber within the appropriate conditions.

1 is a scanning electron microscope of the surface of the nickel-plated carbon fiber by the electroless plating method.

Hereinafter, the present invention will be described in detail.

The present invention provides a method for producing a highly conductive carbon fiber prepared by electrospinning carbon fibers, and nickel-plated on the surface of the carbon fiber by electroless plating.

As a feature of the method of the present invention, the carbon fiber is prepared by electrospinning using polyamideimide as a precursor, and is subjected to oxidation stabilization and carbonization, wherein the average diameter of the carbon fiber is 0.4 to 0.9 m. In addition, the surface of the carbon fiber is nickel plated by surface treatment by chemical reduction method, which can be used commercially as it can be continuously processed like anodizing with little damage to the carbon fiber surface having high conductivity effect. It is a process that can.

The electroless nickel plating liquid according to the present invention contains a nickel salt, a reducing agent and a complexing agent as main components, and nickel ions of the nickel salt form a nickel film on the surface of the carbon fiber by the reducing agent in the plating liquid.

As the nickel salt that can be used in the present invention, and the NiCl _2? 6H ₂ O Preferably, the reducing agent Na ₃ C ₆ H ₅ O ₇ and NaCO ₂ CH ₃ are preferable, and also the complexing agent is NaH ₂ PO ₂ Can be preferably used. In addition, hydrazine or borohydride compounds can be used as reducing agents.

In the above plating solution, the role of nickel chloride is to supply nickel ions in the plating bath, and it is appropriate to use them in the range of 20 to 300 g / l, respectively. In addition, it is appropriate to use the reducing agent and the complexing agent at a concentration of 10 to 160 g / l, respectively.

Moreover, it is suitable to use the pH of the electroless nickel plating liquid of this invention in the range of 3-6 for an acidic bath, and 8-10 for an alkali bath. When using ammonia water (NH ₄ OH) as the pH adjuster in an alkaline plating bath, ammonium forms a complexing agent with nickel ions. However, in the case where caustic alkali is used as the pH adjusting agent, white precipitates of nickel hydroxide may be generated under alkaline conditions without the addition of a complexing agent, and thus it cannot be used as a plating bath. Therefore, when caustic alkali is used as a pH adjuster, a large amount of complexing agent should be used, and citrate is most suitable in consideration of complexation formation and plating rate. In acidic plating baths, it is appropriate to use HCl as the pH adjuster.

In addition, a small amount of PbNO ₃ may be added to the electroless nickel plating bath according to the present invention as a stabilizer. When the plating bath is caustic alkaline, borax or boric acid and NH ₄ Cl may be used in combination with the first complexing agent to increase the plating speed, which helps to improve the precipitation rate in the low temperature alkaline bath.

Further, in the present invention, the plating bath exposure time of the carbon fiber is preferably 3 to 90 minutes. Less than 1 minute is not desirable because the amount of nickel-phosphorus alloy formed on the surface of the carbon fiber is too short because the time of the autocatalytic reaction is too short, and the surface of the carbon fiber due to the large amount of nickel-phosphorus alloy formed after 90 minutes It is not preferable because pit is generated and the metal layer becomes thick enough to lose the inherent properties of the carbon fiber.

In addition, in the present invention, the temperature of the plating solution during the production of the carbon fibers is preferably 40 ° C to 200 ° C.

In addition, in the present invention, the carbon fiber used for electroless plating is preferably subjected to pretreatment to remove metal impurities and then to form metal nuclei in order to activate the fiber surface before electroless plating.

Each characteristic value in the invention was measured by the following method.

Measurement example  1. Metal Electroless  Plated Carbon fiber  Surface structure, thickness change and characteristic check

In order to confirm the surface structure, thickness change and characteristics of the nickel electroless plated carbon fiber prepared in the following examples, an analysis was performed using a scanning electron microscopy and an X-ray diffraction. .

Measurement example  2. Metal Electroless  Plated Carbon fiber  Check conductivity

In order to measure the electrical conductivity of the nickel electroless plated carbon fiber prepared in the following examples, the specimen after measuring the resistance (V / I) using a 4-probe volum resistivity tester (Mitubishi Chemical Co., MCP-T610) The electrical conductivity (σ) was calculated using the relationship with the dimension of.

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.

Example  One.

A spinning solution was prepared using polyamideimide as a precursor, and fibers were prepared by electrospinning. Spinning fibers were dried at room temperature for 24 hours or more, and then made into carbon fibers through oxidation stabilization and carbonization steps.

The carbon fiber prepared by the above method was pretreated with 10wt% HNO ₃ for 30 minutes to remove impurities on the surface before electroless nickel plating, washed with acetone for 2 hours using a Soxhlet apparatus, and dried. After activating in SnCl ₂ solution for 1 minute, it was washed and again activated with PdCl ₂ for 1 minute. In this process, Sn / Pd nuclei are formed on the surface of the carbon fiber, and the Sn / Pd nuclei formed on the surface of the carbon fiber can promote the deposition of metal nickel.

_{NiCl 2? 6H 2 O 280g /} l, NaH 2 PO 2? 2H 2 O 100g / l and NaCO ₂ CH ₃ 15g / year l nickel in the pH 8 having a composition electroless into the processed carbon fibers in a plating solution, 50 The surface of the carbon fiber was surface treated while stirring the solution well using a stirring apparatus at a temperature of (° C. (± 1 ° C.) for 10 minutes, and then completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

Example  2.

Perform the same process as in Example 1, but put the treated carbon fiber in a nickel electroless plating solution, while stirring the solution well using a stirring device for 10 minutes at a temperature of 70 ℃ (± 1 ℃) carbon fiber After surface treatment, it was completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

Example  3.

Perform the same process as in Example 1, but put the treated carbon fiber in the nickel electroless plating solution, while stirring the solution well using a stirring device for 10 minutes at a temperature of 90 ℃ (± 1 ℃) carbon fiber After surface treatment, it was completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

Example  4.

Perform the same process as in Example 1, but put the treated carbon fiber in a nickel electroless plating solution, while stirring the solution well using a stirring device for 10 minutes at a temperature of 110 ℃ (± 1 ℃) carbon fiber After surface treatment, it was completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

Example  5.

Perform the same process as in Example 1, but put the treated carbon fiber in a nickel electroless plating solution, while stirring the solution well using a stirring device for 5 minutes at a temperature of 90 ℃ (± 1 ℃) carbon fiber After surface treatment, it was completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

Example  6.

Perform the same process as in Example 1, but put the treated carbon fiber in the nickel electroless plating solution, while stirring the solution well using a stirring apparatus for 20 minutes at a temperature of 90 ℃ (± 1 ℃) carbon fiber After surface treatment, it was completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

Example  7.

Perform the same process as in Example 1, but put the treated carbon fiber in a nickel electroless plating solution, while stirring the solution well using a stirring device for 30 minutes at a temperature of 90 ℃ (± 1 ℃) carbon fiber After surface treatment, it was completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

Example  8.

Perform the same process as in Example 1, but put the treated carbon fiber in a nickel electroless plating solution, while stirring the solution well using a stirring device for 60 minutes at a temperature of 90 ℃ (± 1 ℃) carbon fiber After surface treatment, it was completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

Comparative example  One.

Perform the same process as in Example 1, but put the treated carbon fiber in a nickel electroless plating solution, while stirring the solution well using a stirring device for 10 seconds at a temperature of 90 ℃ (± 1 ℃) carbon fiber After surface treatment, it was completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

Comparative example  2.

Perform the same process as in Example 1, but put the treated carbon fiber in a nickel electroless plating solution, while stirring the solution well using a stirring device for 200 minutes at a temperature of 90 ℃ (± 1 ℃) carbon fiber After surface treatment, it was completely dried to obtain an electroless nickel plated carbon fiber.

The plating layer thickness and conductivity of the carbon fiber obtained as described above were measured and shown in Table 1.

As a result, as shown in Table 1, in Comparative Example 1, too little metal film was formed, and in Comparative Example 2, the plating layer was formed too thick, so that weaving between fibers occurred.

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 substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (12)

A method for producing nickel plated carbon fibers comprising immersing carbon fibers produced by electrospinning using polyamideimide as a precursor in an electroless plating solution containing nickel salts, reducing agents and complexing agents.
The method of claim 1,
The nickel salt is NiCl ₂ ~ 6H ₂ O, the concentration of the method of producing a nickel-plated carbon fiber, characterized in that the range of 20 to 300g / l.
The method of claim 1,
The reducing agent is Na ₃ C ₆ H ₅ O ₇ or NaCO ₂ CH ₃ , the method of producing a nickel-plated carbon fiber characterized in that the concentration ranges from 10 to 160g / l.
The method of claim 1,
The complexing agent is NaH ₂ PO ₂ , The concentration of the nickel-plated carbon fiber manufacturing method characterized in that the range of 10 to 160g / l.
The method of claim 1,
The plating solution is a method of producing a nickel-plated carbon fiber, characterized in that it further comprises a stabilizer.
The method of claim 1,
The plating solution is a method of producing a nickel-plated carbon fiber, characterized in that the pH ranges from 3 to 10.
The method of claim 1,
The electroless plating solution is caustic alkaline, and further comprising at least one of NH ₄ Cl, borax and boric acid.
delete The method of claim 1,
The carbon fiber is a method of producing a nickel-plated carbon fiber immersed in a plating solution for 1 to 90 minutes.
The method of claim 1,
When the carbon fiber is immersed in the plating solution, the temperature of the plating solution is a method of producing a nickel-plated carbon fiber, characterized in that 40 ℃ to 200 ℃.
The method of claim 1,
The thickness of the film plated on the surface of the carbon fiber is 0.1 to 5.0㎛ manufacturing method of the nickel plated carbon fiber.
The method of claim 1,
Before the carbon fiber is immersed in an electroless plating solution, the method of producing a nickel-plated carbon fiber characterized in that the pre-treatment to wash the surface of the fiber and to form a metal nucleus on the surface.

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