Preparation method of dry-jet wet-spinning carbon fiber precursor with uniform groove structure
By using specially designed spinnerets and plasma etching in the dry-jet wet-spinning carbon fiber preparation process, the problem of uneven carbon fiber surface structure was solved, a uniform groove structure was achieved, and the bonding performance between the fiber and the resin matrix and production efficiency were improved.
Patent Information
- Application Number
- CN202510861913.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-25
- Publication Date
- 2025-09-30
AI Technical Summary
The existing dry-jet wet-spun carbon fibers have a smooth surface and an uneven structure, which makes it difficult to combine with the resin matrix. It is also difficult to form a specific microstructure through plasma etching, and the interface performance cannot be improved.
By using a spinneret with a special groove design in the fiber spinning process, the patented spinning preparation method forms a uniform groove structure through the spinneret design and plasma etching in the spinning hole, combined with steam drawing and etching to improve the fiber surface morphology.
The formation of a uniform groove structure on the surface of the carbon fiber precursor is achieved, the bonding performance between the fiber and the resin matrix is improved, static electricity accumulation and hairiness are reduced, and production efficiency and product quality are improved.
Smart Images
Figure CN120719408A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of carbon fiber preparation and relates to a method for preparing dry-jet wet-spinning carbon fiber precursor with a uniform groove structure. Background Art
[0002] The surface structure of carbon fiber includes the surface physical groove structure and the surface chemical functional group structure. The surface structure of carbon fiber has an important influence on the interfacial properties of composite materials: on the one hand, the groove structure on the surface of carbon fiber provides a meshing center for the bonding between carbon fiber and resin matrix; on the other hand, the chemical functional groups on the surface of carbon fiber can react with the chemical functional group structure of the resin matrix to form chemical bonds, or cause entanglement between molecular chains.
[0003] The surface physical structure of carbon fibers is inherited from polyacrylonitrile (PAN) precursors. Selecting or adjusting the spinning process is an important means of reducing the barriers to carbon fiber surface treatment. Dry-jet wet spinning allows for high drafting, which greatly increases the spinning speed and has high production efficiency. However, the fibers obtained by dry-wet spinning have a uniform structure, a smooth surface, few internal defects, and are difficult to surface treat. Therefore, in order to improve the interfacial properties of carbon fibers, improvements to the dry-jet wet spinning process are needed.
[0004] Plasma equipment can reduce the friction coefficient of fiber surfaces, making them smoother. It also lowers the friction coefficient between fibers and between fibers and processing equipment, minimizing static electricity accumulation and hairiness during processing. This improves fiber spinnability, facilitating a smoother spinning process, reducing breakage rates, and improving production efficiency and product quality. Plasma etching can also adjust fiber surface morphology. By precisely controlling etching parameters, specific microstructures, such as nanoscale grooves and protrusions, can be formed on the fiber surface. These microstructures can improve the cohesion between fibers. Summary of the Invention
[0005] The present invention provides a method for preparing dry-jet wet-spinning carbon fiber precursor with a uniform groove structure. This method improves the surface morphology of the precursor by ejecting the spinning solution through a spinneret with an internal groove structure. After steam drawing, the precursor is plasma-etched to form a uniform groove structure on the surface of the precursor, thereby improving the structure and performance of the precursor.
[0006] The technical solutions of the present invention are as follows:
[0007] The invention discloses a method for preparing dry-jet wet-spinning carbon fiber precursor with a uniform groove structure, which specifically comprises the following steps: ejecting a polyacrylonitrile spinning solution through a spinneret, and then subjecting the solution to a coagulation bath, water washing, water drawing, oiling, drying, and steam drawing, and then subjecting the solution to plasma etching to obtain a polyacrylonitrile carbon fiber precursor with a uniform groove structure, wherein the spinneret is provided with a plurality of petal-shaped spinnerets, the diameter of the spinnerets is 0.1 to 0.3 mm, the number of petals in the petal shape is 5 or more, the circular diameter of the groove part of the petal is 0.0175 mm, and the circular diameter of the raised part of the petal is 0.035±0.005 mm.
[0008] Furthermore, the number of petals in the petal-like shape is 6, and the diameter of the spinneret is 0.15±0.01 mm.
[0009] Furthermore, the spinneret is made of stainless steel and is surface-treated by nickel plating to improve its wear resistance and corrosion resistance.
[0010] Furthermore, the polyacrylonitrile spinning solution is a solution formed by dissolving polyacrylonitrile in dimethyl sulfoxide (DMSO), the mass concentration of which is 18% to 22%, and the average molecular weight of the polyacrylonitrile is 150,000 to 180,000.
[0011] Furthermore, the spinneret is 10 to 20 mm away from the surface of the coagulation bath, and the spinning speed is 5 to 10 m / min.
[0012] Furthermore, the coagulation bath temperature is 20-30° C., and the coagulation bath solution is a mixed solution of water and DMSO in a volume ratio of 7:3.
[0013] Furthermore, the drafting ratio during the water drawing process is 1.5 to 2.5 times.
[0014] Furthermore, the drying temperature is 150-200°C.
[0015] Furthermore, the steam drawing ratio is 2 to 4 times.
[0016] Furthermore, the plasma etching conditions are: the gas is oxygen (O2) or argon (Ar), the gas flow rate is 10-100 sccm, the plasma RF power is 100-500W, the etching time is 5-10s, and the reaction pressure is 10-50Pa.
[0017] Compared with the prior art, the present invention has the following advantages:
[0018] (1) The present invention adopts a spinneret with a special groove design, so that the precursor fiber can be more fully contacted with the solvent during the spinning process, thereby improving the surface morphology of the precursor fiber and enhancing the uniformity and density of the precursor fiber.
[0019] (2) The present invention adds plasma etching after steam drawing to perform surface treatment on the obtained raw silk, so that the groove distribution on the surface of the raw silk is more uniform.
[0020] (3) The preparation method of the present invention is simple to operate, low in cost, and suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 Schematic diagram of the structure of the spinneret;
[0022] Figure 2 This is a SEM image of the carbon fiber precursor prepared in Example 1;
[0023] Figure 3 This is an SEM image of the carbon fiber precursor prepared in Example 2;
[0024] Figure 4 This is an SEM image of the carbon fiber precursor prepared in Comparative Example 1;
[0025] Figure 5 This is the SEM image of the carbon fiber precursor prepared in Comparative Example 2. DETAILED DESCRIPTION
[0026] The present invention will be further described below in conjunction with specific embodiments and accompanying drawings.
[0027] Example 1
[0028] PAN (with an average molecular weight of 150,000-180,000) was slowly added to DMSO with stirring at 300-500 rpm and the temperature controlled at 65°C until the PAN was completely dissolved, forming a spinning solution. The spinneret's orifices were petal-shaped, with a diameter of 0.14 mm and six petals. The circular diameter of the petal recess was 0.0175 mm, and the circular diameter of the petal protrusion was 0.035 mm. The spinneret surface was nickel-plated to improve its surface hardness and corrosion resistance. The spinning solution was delivered to the spinneret via a metering pump. Dry-spraying was performed at a distance of 10 mm from the coagulation bath surface at a speed of 7 m / min. The coagulation bath temperature was 25°C, and the bath solution was a mixture of water and DMSO with a volume ratio of 7:3. The coagulated filaments were then washed and drawn with water, with a draft ratio of 2.3. The tow enters the drying oven for drying at a temperature of 165°C, and then undergoes steam drawing with a drawing ratio of 3.0. During steam drawing, the precursor is plasma etched with oxygen gas at a flow rate of 50 sccm, a plasma RF power of 300W, an etching time of 5s, and a reaction pressure controlled at 50 Pa. Finally, the carbon fiber precursor with uniform and deep grooves on the surface is obtained by winding. Figure 2 shown.
[0029] Example 2
[0030] This embodiment is similar to embodiment 1, except that the gas used for plasma etching is argon. Finally, the carbon fiber precursor with shallow grooves on the surface is obtained by winding. Figure 3 shown.
[0031] Comparative Example 1
[0032] This comparative example is similar to Example 1, except that plasma etching is not performed. Finally, the carbon fiber precursor with uneven surface grooves is obtained by winding. Figure 4 shown.
[0033] Comparative Example 2
[0034] This comparative example is roughly the same as Example 1, except that the circular diameter of the petal groove portion in the spinneret is 0.0175 mm, and the circular diameter of the petal convex portion is 0.045 mm. Finally, the carbon fiber precursor with very shallow surface grooves is obtained by winding. Figure 5 shown.
Claims
1. A method for preparing dry-jet wet-spinning carbon fiber precursor with a uniform groove structure, characterized in that: Specifically, the polyacrylonitrile spinning solution is ejected through a spinneret, and after a coagulation bath, water washing, water drawing, oiling, drying, and steam drawing, the polyacrylonitrile carbon fiber precursor with a uniform groove structure on the surface is obtained by plasma etching. The spinneret is provided with a plurality of petal-shaped spinnerets, the diameter of the spinneret is 0.1~0.3mm, the number of petals in the petal shape is more than 5, the circular diameter of the petal groove part is 0.0175mm, and the circular diameter of the petal convex part is 0.035±0.005mm.
2. The preparation method according to claim 1, characterized in that The number of petals in the petal-like shape is 6, and the diameter of the spinneret is 0.15±0.01 mm.
3. The preparation method according to claim 1, characterized in that The spinneret is made of stainless steel and is nickel-plated.
4. The preparation method according to claim 1, characterized in that The polyacrylonitrile spinning solution is a solution formed by dissolving polyacrylonitrile in DMSO, with a mass concentration of 18% to 22% and an average molecular weight of polyacrylonitrile of 150,000 to 180,000.
5. The preparation method according to claim 1, characterized in that The spinneret is 10-20 mm away from the coagulation bath surface, and the spinning speed is 5-10 m / min.
6. The preparation method according to claim 1, characterized in that The coagulation bath temperature is 20-30°C, and the coagulation bath solution is a mixed solution of water and DMSO in a volume ratio of 7:
3.
7. The preparation method according to claim 1, characterized in that The drafting ratio during the water drawing process is 1.5~2.5 times.
8. The preparation method according to claim 1, characterized in that The drying temperature is 150~200℃.
9. The preparation method according to claim 1, characterized in that The drafting ratio of steam drafting is 2~4 times.
10. The preparation method according to claim 1, wherein The conditions for plasma etching are: the gas is oxygen or argon, the gas flow rate is 10~100 sccm, the plasma RF power is 100~500 W, the etching time is 5~10s, and the reaction pressure is 10~50 Pa.