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CN-119710963-B - Modified heterocyclic aramid fiber and preparation method thereof

CN119710963BCN 119710963 BCN119710963 BCN 119710963BCN-119710963-B

Abstract

The invention provides a preparation method of modified heterocyclic aramid fiber and fiber prepared by the method. The preparation method comprises the steps of S1, dispersing graphene oxide in an N, N-dimethylacetamide solvent to form a dispersion liquid, and S2, adding the dispersion liquid into a polymerization reaction system before polymerizing an aramid fiber III monomer to form a composite spinning solution, wherein C-O/C=O in the graphene oxide is 2-5. According to the invention, graphene oxide with high C-O content is adopted, and N, N-dimethylacetamide is used as a solvent to form a dispersion liquid, so that the graphene oxide is not easy to agglomerate in a composite solvent and is convenient to store, and the C-O in the graphene oxide is easier to partially reduce in the fiber forming process, so that reduced graphene oxide is obtained, and the reduced graphene oxide is more stable relative to the graphene oxide, and the stable storage of the subsequent fiber is ensured. Meanwhile, the graphene oxide is added in the invention, so that the fibrillation of the fiber can be prevented, and the compression performance, the tensile strength and the corrosion resistance are greatly improved.

Inventors

  • JIAO KUN
  • ZHANG ZIYI
  • LI CHUN
  • LI MENGDIE
  • GAO ZHENFEI
  • ZHANG JIN

Assignees

  • 北京石墨烯研究院
  • 北京大学

Dates

Publication Date
20260512
Application Date
20230928

Claims (6)

  1. 1. The preparation method of the modified heterocyclic aramid fiber is characterized by comprising the following steps: S1, dispersing graphene oxide in an N, N-dimethylacetamide solvent to form a dispersion liquid; s2, adding the dispersion liquid into a polymerization reaction system before polymerizing an aramid fiber III monomer to form a composite spinning solution; s3, forming the composite spinning solution into the modified heterocyclic aramid fiber by adopting wet spinning, wherein the temperature of a hot stretching step is 400-420 ℃; wherein, C-O/C=O in the graphene oxide is 2-5, and the C-O/C=O refers to the molar ratio or mass ratio of C-O bonds and C=O bonds; The carbon-oxygen ratio of the graphene oxide is 2-5, and the graphene oxide accounts for 0.02-0.8% of the modified heterocyclic aramid fiber by mass; The step S2 comprises the following steps: dissolving lithium chloride cosolvent, p-phenylenediamine and 2- (4-aminophenyl) -5-aminobenzimidazole in N, N-dimethylacetamide solvent to form solution, cooling the solution to-10-10 ℃, adding the dispersion liquid, stirring for 5-20 minutes, and adding terephthaloyl chloride to react to obtain the composite spinning solution.
  2. 2. The preparation method of claim 1, wherein the graphene oxide has a layer number of 1-10 layers and a sheet diameter of 0.01-3 μm.
  3. 3. The method according to claim 2, wherein the number of layers of the graphene oxide is 1 to 3.
  4. 4. The preparation method according to claim 1, wherein the mass percentage of the graphene oxide in the dispersion liquid is 0.05-0.5%.
  5. 5. The method of claim 1, wherein the viscosity of the composite dope is 3 to 10 centipoise.
  6. 6. A modified heterocyclic aramid fiber prepared by the preparation method of any one of claims 1 to 5.

Description

Modified heterocyclic aramid fiber and preparation method thereof Technical Field The invention relates to the technical field of heterocyclic aramid fibers, in particular to graphene oxide modified heterocyclic aramid fibers and a preparation method thereof. Background The heterocyclic aramid fiber is an organic high-performance fiber with excellent performances such as light weight, high strength, high modulus, impact resistance and the like, and has important application in the fields of aerospace, national defense and military industry and the like such as engine shells of weapon systems, bulletproof helmets, aircraft skins and the like. In engineering application, the domestic heterocyclic aramid fiber still faces a large gap between mechanical properties and foreign countries, and is limited in application field. Therefore, how to develop a series of fiber products according to the structural weakness of the heterocyclic aramid fiber and the requirements of practical application scenes is a key for realizing the application of the heterocyclic aramid fiber. Graphene is a two-dimensional nano carbon material formed by arranging sp 2 hybridized carbon atoms in a honeycomb-like structure, has the characteristics of high strength, high modulus, high specific surface area and the like, and is an ideal structural reinforcing material. At present, some researches are carried out on introducing graphene into heterocyclic aramid fiber, such as adding graphene material into aramid polymer liquid as graphene aramid spinning liquid in Chinese patent No. 113718364A, but direct mixing is easy to agglomerate graphene, so that the aramid composite fiber obtained by spinning is uneven, poor in stability and mechanical property, and difficult to be used for practical production. Compared with the method for directly adding graphene powder, the prepared graphene dispersion liquid can improve the dispersibility of graphene in a spinning solution to a certain extent, for example, in the Chinese patent No. 115216857A, graphene (oxidized graphene or aminated graphene with carboxyl) is dissolved in an N, N dimethylacetamide/lithium chloride composite solvent to obtain a graphene dispersion liquid, and then aramid monomer p-phenylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole and terephthaloyl chloride are added into the graphene dispersion liquid to obtain a graphene aramid spinning liquid. However, lithium chloride in the composite solvent is easy to cause aggregation of graphene due to the effect of salt ions, so that the graphene dispersion liquid cannot be stored for a long time, is only suitable for preparing spinning liquid immediately after preparation is finished, and brings a plurality of inconveniences to actual production. Further, the dissolution of p-phenylenediamine and 2- (4-aminophenyl) -5-aminobenzimidazole in a dispersion of graphene oxide also adversely affects the dispersibility of graphene. In order to ensure better application of the aramid fiber, the stability of the aramid fiber becomes an important evaluation standard. In the present stage, many researches achieve the enhancement effect by introducing graphene oxide into an aramid fiber system, for example, in the Chinese patent No. 115216857A, graphene oxide with carboxyl is added into the aramid fiber system, but the addition of graphene oxide can slowly reduce the mechanical properties of the composite fiber in the later storage and use processes, which brings great hidden danger to the application of the fiber. Disclosure of Invention In order to improve the long-term stability of the mechanical properties of the fiber, the invention provides a preparation method of a modified heterocyclic aramid fiber and the modified heterocyclic aramid fiber prepared by the method. The preparation method of the modified heterocyclic aramid fiber comprises the steps of S1, dispersing graphene oxide in an N, N-dimethylacetamide solvent to form a dispersion liquid, S2, adding the dispersion liquid into a polymerization reaction system before polymerizing an aramid III monomer to form a composite spinning solution, and S3, adopting wet spinning to form the modified heterocyclic aramid fiber from the composite spinning solution, wherein the temperature of a hot stretching step is 400-420 ℃, and C-O/C=O in the graphene oxide is 2-5. According to one embodiment of the invention, the graphene oxide has a carbon-oxygen ratio of 2-5, a layer number of 1-10 layers and a sheet diameter of 0.01-3 μm, and preferably has 1-3 layers. According to another embodiment of the present invention, the graphene oxide content of the dispersion liquid is 0.05-0.5% by mass. According to another embodiment of the invention, the step S2 comprises the steps of dissolving a lithium chloride cosolvent, p-phenylenediamine and 2- (4-aminophenyl) -5-aminobenzimidazole in an N, N-dimethylacetamide solvent to form a solution, reducing the temperature of the solution to-10-10 ℃, adding the d