Preparation process of fiber aramid fiber with high electromagnetic shielding performance

Abstract

The invention discloses a preparation process of fiber aramid fiber with high electromagnetic shielding performance, which comprises the following steps: step 1, dissolving an aramid fiber polymer in concentrated sulfuric acid to form a spinning solution; step 2, adding a nano conductive material and a magnetic material into the spinning stock solution, and treating the mixed solution by adopting an ultrasonic-high-speed shearing synergistic dispersion technology for 30-60 minutes; step 3, extruding the mixed solution into a coagulating bath through a wet spinning process, and performing multi-stage stretching, washing and drying to obtain nascent fibers; 4, performing high-temperature heat treatment and plasma surface modification on the nascent fiber to enhance the continuity of the conductive network; and step 5, coating the surface of the fiber with a polydopamine-metal composite layer. The invention belongs to the technical field of high-performance fiber preparation, and particularly provides a preparation process of fiber aramid fiber with high electromagnetic shielding performance, which optimizes filler selection, a dispersion process and fiber structure design, is high in electromagnetic shielding effectiveness, is suitable for a lightweight environment, and is high in environmental adaptability.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-performance fiber preparation, and specifically refers to a process for preparing aramid fibers with high electromagnetic shielding performance. Background Art

[0002] Aramid fibers are widely used in aerospace, defense, military, environmental protection, construction and other fields due to their properties such as wear resistance, chemical corrosion resistance, high temperature resistance, high strength, high modulus, and flame retardancy. However, traditional aramid fibers do not have electromagnetic shielding capabilities. Studies have shown that the shielding effectiveness can be significantly improved through the composite of nanomaterials and structural gradient design, but there are problems with complex processes and high costs. In the existing technology, the conductivity can be improved by adding metal powder or carbon materials to the fiber, but this can easily lead to problems such as decreased mechanical properties of the fiber and uneven dispersion. Therefore, there is an urgent need for a new fiber aramid preparation process with high electromagnetic shielding performance to solve the above problems. Summary of the Invention

[0003] In order to solve the above-mentioned existing problems, the present invention provides a fiber aramid preparation process with high electromagnetic shielding performance, which optimizes filler selection, dispersion process and fiber structure design, has high electromagnetic shielding efficiency, is suitable for lightweight environments, and has strong environmental adaptability.

[0004] The technical solution adopted by the present invention is as follows: The process for preparing aramid fiber with high electromagnetic shielding performance comprises the following steps:

[0005] Step 1: dissolving the aramid polymer in concentrated sulfuric acid to form a spinning solution;

[0006] Step 2: adding nano-conductive material and magnetic material to the spinning solution, and treating the mixture with ultrasound-high-speed shearing synergistic dispersion technology for 30-60 minutes;

[0007] Step 3: Extruding the mixed solution into a coagulation bath through a wet spinning process, and then undergoing multi-stage stretching, washing, and drying to obtain spun fibers;

[0008] Step 4: High-temperature heat treatment and plasma surface modification are performed on the as-spun fibers to enhance the continuity of the conductive network;

[0009] Step 5: Coat a polydopamine-metal composite layer on the fiber surface to further improve the electromagnetic shielding performance.

[0010] Furthermore, the total mass of the nano-conductive material and the magnetic material is 3-15% of the spinning solution, and the mass ratio of the nano-conductive material to the magnetic material is 2:1 to 5:1.

[0011] Furthermore, the coagulation bath is a low-temperature aqueous solution containing 5-10% sulfuric acid.

[0012] Furthermore, the stretching ratio of the multi-stage stretching is 3-6 times.

[0013] Furthermore, the plasma surface modification is carried out under an argon / oxygen mixed gas with a power of 100-300 W and a treatment time of 5-15 minutes.

[0014] Furthermore, the performance of aramid fiber with high electromagnetic shielding performance was verified: the electromagnetic shielding effectiveness was tested using the waveguide method to verify the synergistic shielding effect of the gradient structure and core-shell fiber; the tensile strength and toughness were tested through dynamic thermomechanical analysis to verify the toughening mechanism of the fiber; the resistance change rate and electromagnetic shielding effectiveness attenuation rate were tested under extreme conditions to verify the stability of the material.

[0015] The beneficial effects achieved by the present invention using the above structure are as follows: the present solution proposes a process for preparing fiber aramid with high electromagnetic shielding performance, optimizes filler selection, dispersion process and fiber structure design, has high electromagnetic shielding efficiency, is suitable for lightweight environments, and has strong environmental adaptability. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0017] Example 1

[0018] The process for preparing aramid fiber with high electromagnetic shielding performance comprises the following steps:

[0019] Step 1: Dissolve the aramid polymer in 98% concentrated sulfuric acid and stir until completely transparent;

[0020] Step 2: Add 5% carbon nanotubes and 2% ferrosoferric oxide nanoparticles, and disperse them by ultrasonic shearing for 40 minutes;

[0021] Step 3: The spinning solution is extruded through a 0.1 mm spinneret into a 5°C, 8% sulfuric acid coagulation bath, and the nascent fiber is stretched 5 times and then washed and dried;

[0022] Step 4: Heat treatment at 350°C in a nitrogen atmosphere for 30 minutes, followed by argon-oxygen plasma treatment for 10 minutes (200W);

[0023] Step 5: Immerse in a polydopamine solution containing 0.5% silver nitrite and react at 60° C. for 2 hours to obtain a finished fiber.

[0024] The performance of aramid fiber with high electromagnetic shielding performance was verified: the electromagnetic shielding effectiveness was tested using the waveguide method to verify the synergistic shielding effect of the gradient structure and core-shell fiber; the tensile strength and toughness were tested through dynamic thermomechanical analysis to verify the toughening mechanism of the fiber; the resistance change rate and electromagnetic shielding effectiveness attenuation rate were tested under extreme conditions to verify the stability of the material.

[0025] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0026] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing aramid fiber with high electromagnetic shielding performance, characterized by: The following steps are involved: Step 1: dissolving the aramid polymer in concentrated sulfuric acid to form a spinning solution; Step 2: adding nano-conductive material and magnetic material to the spinning solution, and treating the mixture with ultrasound-high-speed shearing synergistic dispersion technology for 30-60 minutes; Step 3: Extruding the mixed solution into a coagulation bath through a wet spinning process, and then undergoing multi-stage stretching, washing, and drying to obtain spun fibers; Step 4: High-temperature heat treatment and plasma surface modification are performed on the as-spun fibers to enhance the continuity of the conductive network; Step 5: Coat a polydopamine-metal composite layer on the fiber surface to further improve the electromagnetic shielding performance.

2. The process for preparing aramid fiber with high electromagnetic shielding performance according to claim 1, characterized in that: The total mass of the nano-conductive material and the magnetic material is 3-15% of the spinning solution, and the mass ratio of the nano-conductive material to the magnetic material is 2:1-5:

1.

3. The process for preparing aramid fiber with high electromagnetic shielding performance according to claim 1, characterized in that: The coagulation bath is a low-temperature aqueous solution containing 5-10% sulfuric acid.

4. The process for preparing aramid fiber with high electromagnetic shielding performance according to claim 1, characterized in that: The stretching ratio of the multi-stage stretching is 3-6 times.

5. The process for preparing aramid fiber with high electromagnetic shielding performance according to claim 1, characterized in that: The plasma surface modification is carried out under an argon / oxygen mixed gas with a power of 100-300 W and a treatment time of 5-15 minutes.

6. The process for preparing aramid fiber with high electromagnetic shielding performance according to claim 1, characterized in that: The performance of aramid fiber with high electromagnetic shielding performance was verified: the waveguide method was used to test the X-band electromagnetic shielding effectiveness and verify the synergistic shielding effect of the gradient structure and core-shell fiber; the tensile strength and toughness were tested through dynamic thermomechanical analysis to verify the toughening mechanism of the fiber; the resistance change rate and electromagnetic shielding effectiveness attenuation rate were tested under extreme conditions to verify the stability of the material.