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CN-121976393-A - Carbon fiber surface treatment method

CN121976393ACN 121976393 ACN121976393 ACN 121976393ACN-121976393-A

Abstract

The invention belongs to the field of carbon fibers, and particularly relates to a carbon fiber surface treatment method. The method comprises the steps of carrying out electrochemical oxidation treatment on the carbon fiber by adopting a sulfuric acid solution containing persulfate as electrolyte, washing and drying the carbon fiber after the electrochemical oxidation treatment, wherein the electrochemical oxidation treatment condition comprises that the temperature of the electrolyte is 20-40 ℃, the current density is 0.5-2A/m 2 , and the treatment time is 10-30 seconds. The carbon fiber is subjected to electrochemical oxidation treatment in a sulfuric acid and persulfate mixed system, so that the mild and efficient activation of the surface of the high-strength and high-modulus carbon fiber is realized, the treated carbon fiber not only maintains high tensile strength, but also improves interlayer shear strength. Under the oxidation system of the invention, excessive etching and damage to defects of the fiber body caused by traditional electrochemical treatment are avoided, and high tensile strength is maintained.

Inventors

  • GAO AIJUN
  • XU PANPAN
  • ZHANG SHUBIN
  • XUE YAJUN
  • WANG CHENG
  • BAI XIANGGE

Assignees

  • 江苏恒神股份有限公司

Dates

Publication Date
20260505
Application Date
20260312

Claims (9)

  1. 1. A method for treating a surface of a carbon fiber, comprising: carrying out electrochemical oxidation treatment on the carbon fiber by adopting a sulfuric acid solution containing persulfate as an electrolyte; washing and drying the carbon fiber subjected to electrochemical oxidation treatment; the electrochemical oxidation treatment condition comprises that the temperature of the electrolyte is 20-40 ℃, the current density is 0.5-2A/m 2 , and the treatment time is 10-30 seconds.
  2. 2. The method for surface treatment of carbon fiber according to claim 1, wherein the carbon fiber has a tensile strength of 4000MPa to 5000MPa and a tensile modulus of 530GPa to 570GPa.
  3. 3. The method for surface treatment of carbon fiber according to claim 1, wherein the mass concentration of sulfuric acid in the electrolyte is 0.3-1%.
  4. 4. The method for surface treatment of carbon fiber according to claim 1, wherein the concentration of persulfate in the electrolyte is 0.1 to 0.3mol/L.
  5. 5. The method for treating a surface of a carbon fiber according to claim 1, wherein the persulfate is at least one of ammonium persulfate, potassium persulfate, and sodium persulfate.
  6. 6. The method for surface treatment of carbon fiber according to claim 1, wherein the water temperature of the water washing is 20-40 ℃.
  7. 7. The method for surface treatment of carbon fiber according to claim 1, wherein the drying temperature is 110 to 150 ℃.
  8. 8. The method of claim 1, further comprising sizing, drying, and winding the washed and dried carbon fiber.
  9. 9. A carbon fiber produced by the carbon fiber surface treatment method according to any one of claims 1 to 8.

Description

Carbon fiber surface treatment method Technical Field The invention belongs to the field of carbon fibers, and particularly relates to a carbon fiber surface treatment method. Background Carbon fiber has become an indispensable key material in the field of aerospace and high-end equipment manufacturing due to its excellent properties such as high specific strength and high specific modulus. Through technical evolution for decades, main product series such as high-strength standard type, high-strength middle model, high-strength high model and the like are formed at present. Among them, the high-strength and high-modulus carbon fiber (tensile strength about 4020MPa, tensile modulus about 540 GPa) represented by M55J class is a core material for lightweight aerospace equipment due to its excellent mechanical properties. However, one of the outstanding problems of the M55J-level high-strength high-modulus carbon fiber is that the surface is high in inertia, the interface performance is poor, the performance of the composite material is not easy to develop, and the commercial aerospace requirements of China are difficult to meet. In order to improve the interfacial properties of carbon fiber composites, various surface treatment techniques have been developed, such as anodic oxidation, liquid phase oxidation, plasma treatment, surface grafting, and the like. The anodic oxidation electrolytic method has high treatment efficiency and good controllability, becomes a current universal carbon fiber surface treatment method at home and abroad, and is a continuous treatment technology which is most suitable for being matched with a carbon fiber production line. However, the existing electrochemical oxidation method has the obvious defect that oxidation reaction is more prone to occur at high-activity defect sites on the surface of the fiber, and the expansion and damage deepening of original defects are often caused while the interface bonding performance is improved, so that the tensile strength of a carbon fiber body is obviously reduced. In summary, how to effectively improve the interfacial strength of the high-strength high-modulus carbon fiber and simultaneously minimize the damage to the strength of the fiber body is a key technical problem which is currently restricted to be solved in urgent need of wide application of the high-strength high-modulus carbon fiber. Disclosure of Invention The invention provides a carbon fiber surface treatment method, which aims at the problems existing in the prior art, can realize the surface treatment of high-strength high-modulus carbon fibers, basically does not reduce the tensile strength of the treated carbon fibers, and solves the problem of low shearing strength between layers of a high-strength high-modulus carbon fiber composite material. In order to achieve the above purpose, the technical scheme provided by the invention is as follows: In a first aspect, the present application provides a method for treating a surface of a carbon fiber, comprising: carrying out electrochemical oxidation treatment on the carbon fiber by adopting a sulfuric acid solution containing persulfate as an electrolyte; washing and drying the carbon fiber subjected to electrochemical oxidation treatment; the electrochemical oxidation treatment condition comprises that the temperature of the electrolyte is 20-40 ℃, the current density is 0.5-2A/m 2, and the treatment time is 10-30 seconds. Optionally, the tensile strength of the carbon fiber is 4000MPa-5000MPa, and the tensile modulus is 530GPa-570GPa. Optionally, the mass concentration of sulfuric acid in the electrolyte is 0.3-1%. Optionally, the concentration of persulfate in the electrolyte is 0.1-0.3mol/L. Optionally, the persulfate is at least one of ammonium persulfate, potassium persulfate and sodium persulfate. Optionally, the water temperature of the water wash is 20-40 ℃. Optionally, the temperature of the drying is 110-150 ℃. Optionally, the method further comprises the steps of sizing, drying and rolling the washed and dried carbon fiber. On the other hand, the application also provides a carbon fiber which is prepared by the carbon fiber surface treatment method in the first aspect. Compared with the prior art, the invention has at least the following beneficial effects: According to the invention, the carbon fiber is subjected to electrochemical oxidation treatment in a sulfuric acid and persulfate mixed system, so that the mild and efficient activation of the surface of the high-strength high-modulus carbon fiber is realized, the treated carbon fiber not only maintains high tensile strength, but also improves interlayer shear strength. The surface of the carbon fiber is composed of non-graphite carbon with more defects and graphite carbon with high inertia, under the oxidation system of the invention, mild liquid-phase oxidation mainly occurs at the position with more defects, and severe electrochemical oxidation mainly occurs a