CN-117569076-B - Preparation method of aramid fiber for electromagnetic shielding

Abstract

The invention relates to a preparation method of aramid fiber for electromagnetic shielding. The method comprises the steps of constructing an ultrathin crosslinked layer containing active carboxyl, pyridine or imidazole units on the surface of commercial meta-aramid fiber through interfacial polymerization, synchronously introducing Cu < 2+ >, ag < + >, ni < 2+ > and other metal ions into a reaction solution through coordination of active groups and the metal ions, forming metal nano particles serving as seed crystals on the surface of the aramid fiber after in-situ reduction, and then efficiently constructing a thin and uniform continuous metal conductive coating on the surface of the aramid fiber through metal electroless plating.

Inventors

• Rui Zhangjun
• LI HONG
• HUANG TAO
• GUO MIN
• XU LIMING
• WANG WEI
• ZHU QIUSHI
• MI CHUNHAI
• ZHA WEN
• LIU KAI
• ZHANG JIAWEI
• RUI RUI
• RUI MINMIN

Assignees

• 芜湖航飞科技股份有限公司

Dates

Publication Date

20260508

Application Date

20231108

Claims (6)

1. 1. A preparation method of aramid fiber for electromagnetic shielding is characterized by immersing meta-aramid fiber in a mixed solution of diamine monomer containing active carboxyl, pyridine or imidazole units/ethanol/metal salt for a period of time, transferring the meta-aramid fiber into trimesoyl chloride/n-hexane solution, maintaining the solution for a period of time at room temperature, treating the obtained aramid fiber with a reducing agent to form metal nano particles on the surface of the fiber, then carrying out metal electroless plating on the fiber to form a continuous metal conductive layer on the surface, and finally washing and drying the fiber with deionized water to prepare the aramid fiber for electromagnetic shielding, wherein the diamine containing the active carboxyl, pyridine or imidazole units has one of the following chemical structures: 。
2. 2. The method for producing aramid fiber for electromagnetic shielding according to claim 1, wherein the metal salt is one of copper chloride, silver nitrate, nickel nitrate or nickel sulfate.
3. 3. The method for producing an aramid fiber for electromagnetic shielding according to claim 1, wherein the composition of the mixed solution of diamine monomer/ethanol/metal salt containing active carboxyl, pyridine or imidazole units is (3-5) wt% (90-92) wt% (3-7) wt%, and the treatment time of the aramid fiber in the mixed solution of diamine monomer/ethanol/metal salt containing active carboxyl, pyridine or imidazole units is (10-15) min at room temperature.
4. 4. The method for producing an aramid fiber for electromagnetic shielding according to claim 1, wherein the concentration of trimesic acid chloride/n-hexane solution is (10-25) mmol/L, and the treatment time of the aramid fiber in the solution is (1-3) min at room temperature.
5. 5. The method for producing aramid fiber for electromagnetic shielding according to claim 1, wherein the reducing agent is one of sodium borohydride, hypophosphorous acid or sodium hypophosphite aqueous solution, and the concentration of the reducing agent is (0.1-0.5) mol/L.
6. 6. The method for producing aramid fiber for electromagnetic shielding according to claim 1, wherein the electroless plating solution is commercially available electroless plating solution containing silver, copper, nickel metal salts.

Description

Preparation method of aramid fiber for electromagnetic shielding Technical Field The invention belongs to the technical field of high-performance fiber preparation, and particularly relates to a preparation method of high-performance aramid fiber capable of meeting electromagnetic shielding application. Background As one of high-performance organic fibers, the aramid fiber has the excellent characteristics of high strength, high modulus, excellent heat resistance, intrinsic flame retardance, corrosion resistance and the like, and is widely applied to the fields of aerospace, army equipment, information communication, transportation and the like. Conductive aramid fibers prepared by constructing a continuous conductive coating on the surface of the aramid fibers through chemical or physical modification are currently attracting attention in the electromagnetic shielding field. However, the surface of the aramid fiber is smooth, has strong chemical inertia, is difficult to be combined with other materials, and cannot obtain a continuous and stable metal layer on the surface by physical sputtering, conventional chemical plating deposition and other methods, so that the surface modification treatment of the aramid fiber to improve the reactivity of the aramid fiber is a key to obtaining the high-performance conductive aramid fiber fabric. In order to improve the binding force of the aramid fiber and the conductive coating, the prior treatment measures for the surface of the aramid fiber mainly comprise plasma etching, acid-base etching, chemical grafting and the like. Taking acid-base etching as an example, the main process flow comprises the steps of etching the surface of the fiber by using strong acid or alkali liquor to form a rough groove structure or damage an amide unit on the surface to form an active carboxyl, forming active points of metal nano particles on the surface of the fiber by mechanical engagement or ion coordination, and forming a metal conductive coating on the surface of the fiber by metal chemical plating. For example, the national patent of the application number CN202010242357.6 discloses a method for preparing conductive aramid paper by cleaning aramid and then improving an aramid and metal silver coating by a plasma etching method, and the national patent of the application number CN201911326096.X discloses a method for preparing aramid with a composite metal coating structure, which also comprises the core process of pretreating fibers by using sulfuric acid solution and dimethyl sulfoxide (DMSO) solution of calcium chloride, improving the surface activity and realizing efficient compounding of metal and fibers. The national patent of the invention with the application number of CN201310685423.7 discloses a method for preparing conductive aramid fibers by firstly roughening the surface of the aramid fibers by NaOH etching treatment, then activating by palladium metal and chemically plating silver. However, both physical and chemical etching always result in a decrease in mechanical properties of the fibers at the expense of their physical morphology or chemical structure, and in addition, the formation of the metal nanoparticle "seeds" in the above-described process is separate from the pretreatment of the fibers, which is cumbersome. The lone pair electrons on oxygen or nitrogen atoms in common organic functional groups (such as carboxyl, imidazole, pyridine, 1,2, 4-triazole and the like) have stronger coordination ability with metal ions (Macromolecular Rapid Communications,2022,43 (3): 2100643; polymers,2020,12 (2): 442), and the strong interface recombination of the polymer and the metal nano particles can be realized by utilizing the special interaction. However, how to realize the construction of such special interactions on the surface of aramid fibers without damaging the inherent mechanical properties and flexibility of the aramid fibers, so that the efficient construction of continuous metal conductive coatings is still an important challenge in the field. Disclosure of Invention The invention aims to solve the technical problem of providing a preparation method of conductive aramid fiber for electromagnetic shielding, which aims to overcome the problems of damage to the mechanical properties of fibers caused by physical or chemical etching action and low efficiency caused by complex process flow in the prior art. The invention provides a preparation method of aramid fiber for electromagnetic shielding, which mainly comprises the steps of immersing meta-aramid fiber in a mixed solution of diamine monomer/ethanol/metal salt containing active carboxyl, pyridine or imidazole units, keeping the meta-aramid fiber for a period of time, transferring the meta-aramid fiber into trimesoyl chloride (TMC)/normal hexane solution, keeping the meta-aramid fiber for a period of time at room temperature, treating the obtained aramid fiber with a reducing agent to form metal nano particles o