Preparation method of semi-implanted nano-structure carbon fiber based on dry-jet wet spinning

Abstract

The invention relates to the technical field of nano materials, and discloses a preparation method of semi-implanted nano-structure carbon fibers based on dry-jet wet spinning, which comprises the following steps: connecting one pole of a high-voltage direct-current electric field into a spinneret plate of spinning equipment, so that a polyacrylonitrile spinning solution carries sufficient charges out of the spinneret plate and enters a gas phase layer required by a dry-jet wet spinning process; the method comprises the following steps: performing gas-phase dispersion on a nano material to be coated by using a plasma method, connecting a used dispersion nozzle to another electrode of a high-voltage direct-current electric field, and forming a space electric field which is enough for polarization torsion of an unbalanced nano particle monomer on a gas-phase layer part; the nano particle monomer is polarized and twisted under the action of a space electric field, is attracted by surface charges of the polyacrylonitrile precursor and is finally adsorbed to the surface of the polyacrylonitrile precursor, so that a part of nano particles entering the polyacrylonitrile precursor are positioned within the surface of the fiber, and the other part of the nano particles are positioned outside the surface of the fiber; the specific internal and external proportion is determined according to the final requirements on the carbon fiber strength and the interface strength.

Description

Technical Field

[0001] The invention relates to a method for preparing semi-implanted nanostructured carbon fibers based on dry-jet wet spinning, and in particular to the technical field of nanomaterials. Background Art

[0002] Carbon fiber is a high-performance engineering material, widely used in aerospace, automobile manufacturing and other fields that require lightweight materials. In order to adjust the performance of carbon fiber, functional materials can generally be added to it. For example, spraying 1 to 5 parts of carbon nanotubes can significantly improve the mechanical, thermal, and electrical properties of carbon fiber. The preparation of carbon fiber requires multiple process flows and the production process requires highly specialized equipment and technology, resulting in high raw material and manufacturing costs.

[0003] In recent years, with the vigorous development of nanomaterials, carbon nanotubes have attracted widespread attention as functional materials. At the same time, how to simply and effectively apply carbon nanotubes to the preparation process of carbon fibers, modify carbon nanotubes with carbon nanotubes, and improve the mechanical, thermal, and electrical properties of carbon fibers has become a major technical challenge. Currently known methods mainly include carbon nanotube film modification and carbon nanotube growth on the surface of carbon fibers:

[0004] National invention patent CN202410788408.3 discloses a preparation process of a carbon fiber reinforced resin-based composite material. By epoxidation modification of the carbon nanotube film, the epoxy group content is significantly increased, the interface bonding ability between the carbon nanotube film and the resin matrix is ​​significantly improved, and the tensile properties of the carbon fiber composite material are improved;

[0005] National invention patent CN202310205303.6 discloses a method for growing carbon nanotubes on the surface of carbon fiber based on chemical vapor deposition. First, the epoxy coating on the surface of the carbon fiber is removed, and then the surface of the carbon fiber is activated by plasma technology. Finally, carbon nanotubes are grown on the surface of the activated carbon fiber using chemical vapor deposition technology in a reactor to obtain carbon fiber with surface-grown carbon nanotubes, which significantly improves the bonding strength between the carbon fiber and the resin and the electrical conductivity in the resin.

[0006] However, judging from the existing publicly available technologies, this type of carbon fiber modification technology is cumbersome and involves complex materials. There is currently a lack of nano-modified carbon fiber technology methods that require little change to existing carbon fiber production process equipment and can achieve more optimized mechanical, thermal, and electrical properties. Summary of the invention

[0007] In order to solve the above technical problems, the present invention proposes a method for preparing semi-implanted nanostructured carbon fibers based on dry-jet wet spinning.

[0008] In order to achieve the above object, the technical solution adopted by the present invention to solve its technical problem is:

[0009] 1. Connect one pole of the high-voltage DC electric field to the spinneret of the spinning equipment, so that the polyacrylonitrile spinning solution carries sufficient charge when it leaves the spinneret and enters the gas phase layer required by the dry-jet wet spinning process;

[0010] 2. The nanomaterial to be coated is dispersed in the gas phase by plasma method, wherein the dispersant used must be compatible with the polyacrylonitrile solution solvent in dry-jet wet spinning;

[0011] 3. Introduce the nanoparticles dispersed in step 2 into the gas phase layer in step 1 by free flow, diffusion or external air flow driving;

[0012] 4. The dispersion nozzle used for plasma dispersion in step 2 is connected to another electrode of the high voltage DC electric field in step 1, so as to form a spatial electric field sufficient for polarization twisting of non-equilibrium nanoparticle monomers in the gas phase layer of the carbon nanotube movement path;

[0013] 5. The distance between the plasma dispersion nozzle and the spinneret for ejecting the polyacrylonitrile precursor in step 2 is not less than the necessary long moving distance required for the polarization twisting of the non-equilibrium nanoparticle monomer and not more than 2 times of the distance;

[0014] 6. The nanoparticle monomers undergo polarization twisting under the action of the spatial electric field and are attracted by the surface charge of the polyacrylonitrile precursor and finally adsorbed onto the surface of the polyacrylonitrile precursor;

[0015] 7. Under the action of microscopic wetting force, the nanoparticle monomer moves into the interior of the polyacrylonitrile precursor. The moving speed is mainly determined by complex conditions and factors such as the strength of the interaction between the components of the polyacrylonitrile precursor and the nanoparticles. Therefore, the present invention controls the final distance of the nanoparticle monomer moving into the interior of the polyacrylonitrile precursor by adjusting the thickness of the gas phase layer and the spinning rate of the precursor.

[0016] 8. Through the modulation of step 7, part of the nanoparticles entering the polyacrylonitrile precursor are located inside the fiber surface, and the other part are located outside the fiber surface. The specific inside-outside ratio depends on the final requirements for carbon fiber strength and interface strength. The general principle is that the nanoparticle structure located inside the fiber surface is conducive to the combination of the force, heat, electricity and other properties of the nanoparticles and the fiber, and the nanoparticle structure located outside the fiber surface is conducive to the combination of the force, heat, electricity and other properties of the nanoparticles and the matrix;

[0017] 9. According to the dry-jet wet-spinning process, the polyacrylonitrile fiber precursor with semi-embedded nanostructures modulated and designed in the above steps is cured and post-treated to obtain semi-embedded nanostructured polyacrylonitrile fibers based on dry-jet wet-spinning;

[0018] 10. Carbonize the semi-implanted nanostructured polyacrylonitrile fiber based on dry-jet wet spinning obtained in step 9 according to the carbon fiber preparation process to obtain the semi-implanted nanostructured carbon fiber based on dry-jet wet spinning.

[0019] The beneficial effects of the present invention are that, based on the dry-jet wet spinning process, without changing the fiber preparation process, the nano-dispersion technology is connected to prepare a carbon fiber surface with a directional structure and at the same time a new microscopic nanostructure that can penetrate to a certain depth on the carbon fiber surface and outside the carbon fiber surface. The existing carbon fiber production process equipment is changed less and nano-modified carbon fibers with better mechanical, electrical and thermal properties can be obtained. More importantly, a new carbon fiber prepared from a composite material with better interface properties is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the operation flow of the method for preparing semi-implanted nanostructured carbon fiber based on dry-jet wet spinning of the present invention.

[0021] Figure 2 It is a schematic diagram of the carbon nanotubes of the present invention embedded in the surface of polyacrylonitrile precursor. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings, and the following is known as one of the examples:

[0023] 1. Connect the positive electrode of the 4KV high-voltage DC electric field to the spinneret of the spinning equipment, so that the polyacrylonitrile and dimethyl sulfoxide spinning solution carries sufficient charge out of the spinneret and enters the gas phase layer required for the dry-jet wet spinning process;

[0024] 2. The carbon nanotubes to be coated are dispersed in the gas phase by plasma method, wherein the dispersant used is water;

[0025] 3. Introducing the carbon nanotubes dispersed in step 2 into the gas phase layer in step 1 through free flow;

[0026] 4. The dispersion nozzle used for plasma dispersion in step 2 is connected to the negative electrode of the 4KV high voltage DC electric field in step 1, so as to form a spatial electric field sufficient for polarization twisting of the non-equilibrium carbon nanotube monomers in the gas phase layer of the carbon nanotube movement path;

[0027] 5. The distance between the plasma dispersion nozzle and the spinneret for ejecting the polyacrylonitrile precursor in step 2 is twice the necessary long moving distance required for the polarization twisting of the unbalanced carbon nanotube monomer;

[0028] 6. The carbon nanotube monomer undergoes polarization twisting under the action of the spatial electric field and is attracted by the surface charge of the polyacrylonitrile precursor and finally adsorbed onto the surface of the polyacrylonitrile precursor;

[0029] 7. The thickness of the gas phase layer is set to 20 mm, and the spinning rate of the raw fiber is 5 m / min;

[0030] 8. Curing and post-treating the polyacrylonitrile fiber precursor with semi-implanted nanostructures modulated and designed by the dry-jet wet spinning process to obtain semi-implanted nanostructured polyacrylonitrile fibers based on dry-jet wet spinning;

[0031] 9. Carbonize the semi-implanted nanostructured polyacrylonitrile fiber based on dry-jet wet spinning obtained in step 9 according to the carbon fiber preparation process to obtain the semi-implanted nanostructured carbon fiber based on dry-jet wet spinning.

Claims

1. Connect one electrode of a high-voltage direct current electric field to a spinning device spinneret, so that the polyacrylonitrile spinning solution carries sufficient charge when it leaves the spinneret and enters the gas phase layer required by the dry-jet wet spinning process; use a plasma method to disperse the required nanomaterial in the gas phase, wherein the dispersant used must be compatible with the solvent of the polyacrylonitrile solution in the dry-jet wet spinning process; introduce the dispersed nanoparticles into the gas phase layer through free flow, diffusion or external air flow drive; connect the dispersing nozzle used for plasma dispersion to another electrode of the high-voltage direct current electric field, and form a space electric field sufficient for the non-equilibrium nanoparticle monomer to undergo polarization twisting in the gas phase layer of the carbon nanotube movement path; the distance between the plasma dispersing nozzle and the polyacrylonitrile precursor sprayed from the spinneret is not less than the necessary long moving distance required for the non-equilibrium nanoparticle monomer to undergo polarization twisting and is not more than 2 times the distance; the nanoparticle monomer undergoes polarization twisting under the action of the space electric field and is attracted by the surface charge of the polyacrylonitrile precursor and finally adsorbed to the surface of the polyacrylonitrile precursor; under the action of the microscopic wetting force, the nanoparticle monomer moves into the interior of the polyacrylonitrile precursor, and the moving speed is mainly affected by the polyacrylonitrile The invention relates to a method for preparing a polyacrylonitrile precursor fiber. The method comprises the steps of adjusting the thickness of the gas phase layer and the spinning rate of the precursor fiber to control the final distance of the nanoparticle monomer moving into the interior of the polyacrylonitrile precursor fiber. The method comprises the steps of: .... The method comprises the steps of: adjusting the thickness of the gas phase layer and the spinning rate

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