Preparation method of high-temperature-resistant carbon fiber

Abstract

The invention belongs to the field of preparation of carbon fibers, and particularly relates to a preparation method of high-temperature-resistant carbon fibers, which specifically comprises the following steps: step 1, cleaning an unwound fiber base material, taking out impurities on the surface of the fiber base material, then repeatedly washing with deionized water, and drying until the water content is 15-18%; step 2, feeding the fiber base material obtained in the step 1 into a drying box, controlling the mass concentration of carbon monoxide in the drying box to be 16-20%, and beating the fiber base material for the first time by utilizing airflow; step 3, spraying a treating fluid to the fiber base material treated in the step 2, then feeding the fiber base material into a drying box, controlling the mass concentration of carbon monoxide in the drying box to be 8-12%, and performing secondary flapping on the fiber base material by utilizing airflow; 4, sputtering a SiC and / or SiO2 layer on the surface of the dried fiber base material; and step 5, oiling, drying and shaping the fiber base material obtained in the step 4 to obtain the high-temperature-resistant carbon fiber. The temperature resistance of the prepared carbon fiber is improved to 1200 DEG C or above.

Description

Technical Field

[0001] The present invention belongs to the field of carbon fiber preparation, and particularly relates to a method for preparing high-temperature resistant carbon fiber. Background Art

[0002] With the rapid development of the aerospace, national defense industry, and high-temperature engineering fields, the demand for high-performance high-temperature resistant materials is increasing day by day. Due to its excellent mechanical properties, low density, and high modulus, carbon fiber has become an important reinforcing material for advanced composites. However, carbon fiber is prone to oxidation and thermal decomposition in high-temperature environments, which limits its application under extreme conditions. To solve this problem, surface coating treatment of carbon fiber to improve its high-temperature resistance and oxidation resistance has become one of the research hotspots in the field of materials science.

[0003] As an important ceramic material, silicon carbide has high hardness, high wear resistance, high thermal conductivity, and excellent oxidation resistance, and is widely used in high-temperature structural materials and functional materials. By using silicon carbide as a coating material and forming a dense SiC coating on the surface of carbon fiber, oxygen and moisture can be effectively isolated, preventing the oxidation and thermal decomposition of carbon fiber in high-temperature environments, thereby significantly improving the high-temperature resistance and service life of carbon fiber.

[0004] At present, the technologies for coating SiC on the surface of carbon fiber mainly include the embedding method, chemical vapor deposition (CVD) method, sputtering method, solution impregnation method, etc. These methods have their own advantages and disadvantages in terms of coating uniformity, density, and bonding strength. For example, the chemical vapor deposition method can achieve a high-density and uniform SiC coating, but the process is complex, the cost is high, and the requirements for equipment are harsh; the sputtering method has a high deposition rate, but the coating uniformity and oxidation resistance are poor; the solution impregnation method and the embedding method have problems of poor coating uniformity and density, and it is difficult to meet the harsh requirements in high-temperature environments and urgently need to be improved. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing high-temperature resistant carbon fiber.

[0006] The present invention adopts the following technical solutions: A method for preparing high-temperature resistant carbon fiber specifically includes the following steps: Step 1, clean the unrolled fiber substrate, remove the impurities on the surface of the fiber substrate, then repeatedly rinse with deionized water, and dry until the moisture content is 15-18%; Step 2, send the fiber substrate obtained in Step 1 into a drying oven, control the mass concentration of carbon monoxide in the drying oven to be 16-20%, use air flow to pat the fiber substrate once, the patting time is 10-15 min, and the patting intensity is 30-40 Pa / m; Step 3: Spray the treatment liquid on the fiber substrate processed in Step 2, and then send it into a drying oven. Control the mass concentration of carbon monoxide in the drying oven to be 8 - 12%, and use air flow to perform secondary patting on the fiber substrate. The patting time is 10 - 15 minutes, and the patting intensity is 18 - 25 Pa / m; Step 4: Install the dried fiber substrate on the fixed bracket of the fiber splitting device, and send it into the sputtering reaction chamber. First, evacuate the reaction chamber to the background vacuum, and then fill it with high-purity inert gas as the sputtering gas. The sputtering process parameters are as follows: Use a SiC target or a SiO 2 target as the target material. When sputtering the SiC target, the sputtering power is 100 - 500 W, and the sputtering time is 10 - 30 minutes; when sputtering the SiO 2 target, the sputtering power is 60 - 120 W, and the sputtering time is 10 - 30 minutes; to form a high-temperature coating with a thickness of 150 mm on the surface of the fiber substrate. Among them, the sputtering gas pressure is 0.5 - 5 Pa, and the gas flow rate is 5 - 30 mL / min; Step 5: Perform oiling, drying, and shaping treatments on the fiber substrate obtained in Step 4 to obtain the high-temperature resistant carbon fiber.

[0007] Preferably, in Step 3, the treatment liquid uses ethanol as the solvent, wherein the mass fraction of tert-butyl glycidyl ether is 3 - 5%, the mass fraction of triethoxyvinylsilane is 2 - 3%, and the mass fraction of fatty alcohol polyoxyethylene ether is 1.2 - 1.5%.

[0008] Preferably, in Step 5, after installing the dried fiber substrate on the fixed bracket of the fiber splitting device, start the fiber splitting device drive system, and evenly separate the fiber substrate into multiple independent small filament bundles through the fiber splitting roller or the yarn splitting device to form a plane; during the fiber splitting process, the fiber splitting roller drives the fiber filament bundle to perform periodic back-and-forth movements along the axial direction, and at the same time directly introduces the moving split fibers into the dynamic transmission device in the sputtering cavity to ensure that the fibers maintain continuous and uniform movement in the sputtering area.

[0009] Preferably, in Step 5, in the oiling treatment, the oiling agent includes the following raw materials in parts by weight: 50 - 60 parts of amino silicone oil, 10 - 15 parts of polyether modified silicone oil, 6 - 8 parts of polydimethylsiloxane, 3 - 4 parts of high-carbon fatty alcohol polyoxyethylene ether, and 1 - 2 parts of alkyl alcohol polyoxyethylene ether.

[0010] Preferably, in Step 1, the cleaning process is specifically as follows: Fix the unrolled substrate on the bracket, burn it with a propane flame for 30 s, naturally cool it, then send it into the cleaning solution, clean it at 50 - 60 °C for 25 - 35 minutes, and then repeatedly rinse it with deionized water and dry it until the moisture content is 15 - 18%.

[0011] Preferably, the cleaning solution comprises 10 g / L of sodium carbonate, 6 g / L of sodium lignosulfonate, and 2 g / L of sodium dodecyl sulfate.

[0012] Preferably, in step 5, the addition amount of the oiling agent accounts for 0.4 - 0.6% of the total mass of the fiber substrate.

[0013] Preferably, in step 5, the drying temperature is 120 - 150 °C.

[0014] Preferably, in step 5, the shaping temperature is 100 - 150 °C.

[0015] As can be seen from the above description of the present invention, compared with the prior art, the beneficial effects of the present invention are as follows: By defining the preparation method of carbon fiber, a primary patting and a secondary patting are carried out respectively before the sputtering treatment to destroy the oxide layer formed on the surface of the fiber substrate, and a treatment liquid needs to be sprayed before the secondary patting to improve the surface activity and adhesion ability of the fiber substrate, thereby improving the uniformity and bonding strength of the surface coating of the fiber substrate, and increasing the heat resistance of the prepared carbon fiber from the original 500 - 800 °C to above 1200 °C, providing a reliable material basis for the application of high-performance composite materials in extreme environments; Specifically define the raw material composition of the oiling agent, with amino silicone oil as the main raw material, introducing polyether-modified silicone oil, high-carbon fatty alcohol polyoxyethylene ether, and alkyl alcohol polyoxyethylene ether to improve the antioxidant property and heat resistance of the surface coating of the fiber substrate and broaden the use environment of carbon fiber. Specific Embodiments

[0016] The present invention will be further described below through specific embodiments.

[0017] A preparation method of high-temperature resistant carbon fiber specifically comprises the following steps: Step 1, fix the unrolled substrate on a bracket, burn it with a propane flame for 30 s, naturally cool it, then send it into the cleaning solution, clean it at 50 - 60 °C for 25 - 35 min, and then repeatedly rinse it with deionized water and dry it to a moisture content of 15 - 18%; Step 2, send the fiber substrate obtained in step 1 into a drying oven, control the mass concentration of carbon monoxide in the drying oven to be 16 - 20%, and use air flow to conduct a primary patting on the fiber substrate for 10 - 15 min with a patting force of 30 - 40 Pa / m; Step 3, spray the treatment liquid on the fiber substrate processed in step 2, then send it into the drying oven, control the mass concentration of carbon monoxide in the drying oven to be 8 - 12%, and use air flow to conduct a secondary patting on the fiber substrate for 10 - 15 min with a patting force of 18 - 25 Pa / m; Step 4: Install the dried fiber substrate on the fixed bracket of the fiber splitting device, start the fiber splitting device drive system, and evenly separate the fiber substrate into multiple independent small fiber bundles through the fiber splitting roller or yarn splitting device to form a plane. During the fiber splitting process, the fiber splitting roller drives the fiber bundle to perform periodic reciprocating motion along the axial direction, and at the same time directly introduces the moving fiber splitting fibers into the dynamic transmission device in the sputtering chamber to ensure that the fibers maintain continuous and uniform motion in the sputtering area. During sputtering, first evacuate the reaction chamber to the background vacuum, and then fill it with high-purity inert gas as the sputtering gas. The sputtering process parameters are as follows: Use a SiC target or SiO 2 target as the target material. When sputtering the SiC target, the sputtering power is 100 - 500 W, and the sputtering time is 10 - 30 min; when sputtering the SiO 2 target, the sputtering power is 60 - 120 W, and the sputtering time is 10 - 30 min; to form a high-temperature coating with a thickness of 150 mm on the surface of the fiber substrate. Among them, the sputtering gas pressure is 0.5 - 5 Pa, and the gas flow rate is 5 - 30 mL / min; Step 5: Perform oiling, drying, and shaping treatments on the fiber substrate obtained in Step 4 to obtain the high-temperature resistant carbon fiber. Among them, the drying temperature is 120 - 150 °C, and the shaping temperature is 100 - 150 °C.

[0018] Among them, in Step 1, the cleaning solution includes 10 g / L of sodium carbonate, 6 g / L of sodium lignosulfonate, and 2 g / L of sodium dodecyl sulfate; the fiber substrate is carbon fibers from various sources, including both existing carbon fiber products on the market and carbon fibers after specific treatment and recycling.

[0019] In Step 3, the treatment solution uses ethanol as the solvent. Among them, the mass fraction of tert-butyl glycidyl ether is 3 - 5%, the mass fraction of triethoxyvinylsilane is 2 - 3%, and the mass fraction of fatty alcohol polyoxyethylene ether is 1.2 - 1.5%.

[0020] In Step 5, during the oiling treatment, the addition of the oiling agent accounts for 0.4 - 0.6% of the total mass of the fiber substrate, and it includes the following raw materials in parts by weight: 50 - 60 parts of amino silicone oil, 10 - 15 parts of polyether modified silicone oil, 6 - 8 parts of polydimethylsiloxane, 3 - 4 parts of high-carbon fatty alcohol polyoxyethylene ether, and 1 - 2 parts of alkyl alcohol polyoxyethylene ether. Example 1

[0021] A preparation method of high-temperature resistant carbon fiber specifically includes the following steps: Step 1: Fix the unrolled substrate on the bracket, burn it with a propane flame for 30 s, naturally cool it, then send it into the cleaning solution, clean it at 50 °C for 35 min, and then repeatedly rinse it with deionized water and dry it to a moisture content of 15%; Step 2, sending the fiber substrate obtained in step 1 into a drying oven, controlling the carbon monoxide mass concentration in the drying oven to be 16%, and using airflow to beat the fiber substrate once, the beating time is 15 minutes, and the beating force is 30Pa / m; Step 3, spraying the treatment liquid on the fiber substrate treated in step 2, and then sending it into a drying oven, controlling the carbon monoxide mass concentration in the drying oven to be 8%, and using airflow to beat the fiber substrate twice, the beating time is 15 minutes, and the beating force is 18Pa / m; Step 4, the dried fiber substrate is mounted on the fixed bracket of the wire separator, the driving system of the wire separator is started, and the fiber substrate is evenly separated into multiple independent small bundles through the wire separator roller or the yarn separator device to form a plane; during the wire separation process, the wire separator roller drives the fiber bundle to perform periodic reciprocating motion along the axial direction, and at the same time, the moving wire fibers are directly introduced into the dynamic transmission device in the sputtering chamber to ensure that the fibers maintain continuous and uniform motion in the sputtering area. During sputtering, the reaction chamber is first vacuumed until the background vacuum state is reached; then, argon containing 20% ​​oxygen is filled into the reaction chamber as the sputtering gas, and the specific sputtering process parameters are set as follows: high purity SiO 2 The target was used as the target material, the sputtering power was set to 150W, the sputtering time was 20min, the sputtering gas pressure was 1Pa, and the gas flow rate was controlled to 20mL / min; the sample holder was rotated at a speed of 30r / min. During the sputtering process, the film thickness was monitored and controlled in real time using a film thickness meter to form a high-temperature coating with a thickness of 150nm; Step 5, oiling, drying and shaping the fiber substrate obtained in step 4 to obtain the high temperature resistant carbon fiber, wherein the drying temperature is 120°C and the shaping temperature is 100°C.

[0022] Wherein, in step 1, the cleaning solution includes 10 g / L sodium carbonate, 6 g / L sodium lignin sulfonate, and 2 g / L sodium dodecyl sulfate.

[0023] In step 3, the treatment liquid uses ethanol as a solvent, wherein the mass fraction of tert-butyl glycidyl ether is 3%, the mass fraction of triethoxyvinyl silane is 3%, and the mass fraction of fatty alcohol polyoxyethylene ether is 1.2%.

[0024] In step 5, during the oiling treatment, the amount of oiling agent added accounts for 0.4% of the total mass of the fiber substrate, including the following raw materials in parts by weight: 50 parts of amino silicone oil, 15 parts of polyether modified silicone oil, 6 parts of polydimethylsiloxane, 4 parts of high-carbon fatty alcohol polyoxyethylene ether, and 1 part of alkyl alcohol polyoxyethylene ether. Example 2

[0025] A method for preparing high temperature resistant carbon fiber specifically comprises the following steps: Step 1: Fix the unrolled substrate on the bracket, burn it with propane flame for 30 s, cool it naturally, then send it into the cleaning solution, clean it at 60 °C for 25 min, rinse it repeatedly with deionized water, and dry it until the moisture content is 18%. Step 2: Send the fiber substrate obtained in Step 1 into the drying oven, control the mass concentration of carbon monoxide in the drying oven to be 20%, use air flow to pat the fiber substrate once, the patting time is 10 min, and the patting strength is 40 Pa / m. Step 3: Spray the treatment liquid on the fiber substrate processed in Step 2, then send it into the drying oven, control the mass concentration of carbon monoxide in the drying oven to be 12%, use air flow to pat the fiber substrate twice, the patting time is 10 min, and the patting strength is 25 Pa / m. Step 4: Install the dried fiber substrate on the fixed bracket of the fiber splitting device, start the driving system of the fiber splitting device, and evenly separate the fiber substrate into multiple independent small filament bundles through the fiber splitting roller or yarn splitting device to form a plane; during the fiber splitting process, the fiber splitting roller drives the fiber bundle to perform periodic reciprocating motion along the axis, and at the same time directly introduces the moving fiber splitting fiber into the dynamic transmission device in the sputtering chamber to ensure that the fiber maintains continuous and uniform motion in the sputtering area. During sputtering, first pump the reaction chamber to the background vacuum, and then fill the reaction chamber with high-purity argon as the sputtering gas. The specific sputtering process parameters are set as follows: Select a high-purity SiC target as the target material, set the sputtering power to 150 W, the sputtering time to 20 min, the sputtering pressure to 1 Pa, and the gas flow rate to 20 mL / min; among them, the sample holder rotates at a speed of 30 r / min; during sputtering, use a film thickness gauge to monitor and control the film thickness in real time to form a high-temperature coating with a thickness of 150 nm. Step 5: Perform oiling, drying, and shaping treatments on the fiber substrate obtained in Step 4 to obtain the high-temperature resistant carbon fiber, where the drying temperature is 150 °C and the shaping temperature is 150 °C.

[0026] Among them, in Step 1, the cleaning solution includes 10 g / L of sodium carbonate, 6 g / L of sodium lignosulfonate, and 2 g / L of sodium dodecyl sulfate.

[0027] In Step 3, the treatment liquid uses ethanol as the solvent, where the mass fraction of tert-butyl glycidyl ether is 5%, the mass fraction of triethoxyvinylsilane is 2%, and the mass fraction of fatty alcohol polyoxyethylene ether is 1.5%.

[0028] In Step 5, in the oiling treatment, the addition of the oiling agent accounts for 0.6% of the total mass of the fiber substrate, and it includes the following raw materials in parts by weight: 60 parts of amino silicone oil, 10 parts of polyether-modified silicone oil, 8 parts of polydimethylsiloxane, 3 parts of high-carbon fatty alcohol polyoxyethylene ether, and 2 parts of alkyl alcohol polyoxyethylene ether. Example 3

[0029] A preparation method of high-temperature resistant carbon fiber, specifically including the following steps: Step 1: Fix the unwound substrate on the bracket, burn it with propane flame for 30 s, send it into the cleaning solution after natural cooling, clean it at 55 °C for 30 min, then rinse it repeatedly with deionized water, and dry it until the moisture content is 16%; Step 2: Send the fiber substrate obtained in Step 1 into the drying oven, control the mass concentration of carbon monoxide in the drying oven to be 18%, use air flow to pat the fiber substrate once, the patting time is 12 min, and the patting strength is 35 Pa / m; Step 3: Spray the treatment solution on the fiber substrate processed in Step 2, then send it into the drying oven, control the mass concentration of carbon monoxide in the drying oven to be 10%, use air flow to pat the fiber substrate twice, the patting time is 12 min, and the patting strength is 22 Pa / m; Step 4: Install the dried fiber substrate on the fixed bracket of the wire splitting device, start the wire splitting device drive system, evenly separate the fiber substrate into multiple independent small filament bundles through the wire splitting roller or yarn splitting device to form a plane; during the wire splitting process, the wire splitting roller drives the fiber filament bundle to perform periodic reciprocating motion along the axis, and at the same time directly introduces the moving wire splitting fiber into the dynamic transmission device in the sputtering chamber to ensure that the fiber maintains continuous and uniform motion in the sputtering area. During sputtering, first pump the reaction chamber to the background vacuum, and then fill the reaction chamber with argon containing 20% oxygen as the sputtering gas. The specific sputtering process parameters are set as follows: Select high-purity SiO 2 target as the target material, set the sputtering power to 150 W, the sputtering time to 20 min, the sputtering pressure to 1 Pa, and the gas flow rate to 20 mL / min; among them, the sample rack rotates at a speed of 30 r / min; during sputtering, use a film thickness gauge to monitor and control the film thickness in real time to form a high-temperature coating with a thickness of 150 nm; Step 5: Perform oiling, drying, and shaping treatments on the fiber substrate obtained in Step 4 to obtain the high-temperature resistant carbon fiber, where the drying temperature is 135 °C and the shaping temperature is 130 °C.

[0030] Among them, in Step 1, the cleaning solution includes 10 g / L of sodium carbonate, 6 g / L of sodium lignosulfonate, and 2 g / L of sodium dodecyl sulfate.

[0031] In Step 3, the treatment solution uses ethanol as the solvent, where the mass fraction of tert-butyl glycidyl ether is 4%, the mass fraction of triethoxyvinylsilane is 2.5%, and the mass fraction of fatty alcohol polyoxyethylene ether is 1.3%.

[0032] In Step 5, during the oiling treatment, the addition of the oiling agent accounts for 0.5% of the total mass of the fiber substrate, and it includes the following raw materials in parts by weight: 55 parts of amino silicone oil, 12 parts of polyether-modified silicone oil, 7 parts of polydimethylsiloxane, 3.5 parts of higher fatty alcohol polyoxyethylene ether, and 1.5 parts of alkyl alcohol polyoxyethylene ether.

[0033] Comparative Example 1 A method for preparing high-temperature resistant carbon fiber specifically includes the following steps: Step 1: Fix the unwound substrate on the bracket, burn it with propane flame for 30 s, naturally cool it, then send it into the cleaning solution, clean it at 55 °C for 30 min, repeatedly rinse it with deionized water, and then dry it until the moisture content is 16%. Step 2: Install the dried fiber substrate on the fixed bracket of the fiber splitting device, start the fiber splitting device drive system, evenly separate the fiber substrate into multiple independent small filaments through the fiber splitting roller or yarn splitting device to form a plane; during the fiber splitting process, the fiber splitting roller drives the fiber bundle to perform periodic reciprocating motion along the axis, and at the same time directly introduces the moving split fibers into the dynamic transmission device in the sputtering chamber to ensure that the fibers maintain continuous and uniform motion in the sputtering area. During sputtering, first pump the reaction chamber to the base vacuum, and then fill the reaction chamber with argon containing 20% oxygen as the sputtering gas. The specific sputtering process parameters are set as follows: Select high-purity SiO 2 target as the target material, set the sputtering power to 150 W, the sputtering time to 20 min, the sputtering pressure to 1 Pa, and the gas flow rate to 20 mL / min; among them, the sample rack rotates at a speed of 30 r / min; during sputtering, use a film thickness gauge to monitor and control the film thickness in real time to form a high-temperature coating with a thickness of 150 nm. Step 3: Perform oiling, drying, and shaping treatments on the fiber substrate obtained in Step 2 to obtain the high-temperature resistant carbon fiber, where the drying temperature is 135 °C and the shaping temperature is 130 °C.

[0034] Among them, in Step 1, the cleaning solution includes 10 g / L of sodium carbonate, 6 g / L of sodium lignosulfonate, and 2 g / L of sodium dodecyl sulfate.

[0035] In Step 3, during the oiling treatment, the addition of the oiling agent accounts for 0.5% of the total mass of the fiber substrate, and it includes the following raw materials in parts by weight: 55 parts of amino silicone oil, 12 parts of polyether-modified silicone oil, 7 parts of polydimethylsiloxane, 3.5 parts of higher fatty alcohol polyoxyethylene ether, and 1.5 parts of alkyl alcohol polyoxyethylene ether.

[0036] Comparative Example 2 A method for preparing high-temperature resistant carbon fiber specifically includes the following steps: Step 1: Fix the unwound substrate on the bracket, burn it with a propane flame for 30 s, let it cool naturally, then send it into the cleaning solution, clean it at 55 °C for 30 min, rinse it repeatedly with deionized water, and dry it until the moisture content is 16%. Step 2: Send the fiber substrate obtained in Step 1 into the drying oven, control the mass concentration of carbon monoxide in the drying oven to be 18%, use the air flow to pat the fiber substrate once, with a patting time of 12 min and a patting intensity of 35 Pa / m; Step 3: Spray the treatment liquid on the fiber substrate treated in Step 2, then send it into the drying oven, control the mass concentration of carbon monoxide in the drying oven to be 10%, use the air flow to pat the fiber substrate twice, with a patting time of 12 min and a patting intensity of 22 Pa / m; Step 4: Install the dried fiber substrate on the fixed bracket of the fiber splitting device, start the driving system of the fiber splitting device, and evenly separate the fiber substrate into multiple independent small filament bundles through the fiber splitting roller or yarn splitting device to form a plane; during the fiber splitting process, the fiber splitting roller drives the fiber filament bundle to perform periodic reciprocating motion along the axis, and at the same time directly introduces the moving fiber splitting fiber into the dynamic transmission device in the sputtering chamber to ensure that the fiber maintains continuous and uniform motion in the sputtering area. During sputtering, first pump the reaction chamber to the background vacuum, and then fill the reaction chamber with argon containing 20% oxygen as the sputtering gas. The specific sputtering process parameters are set as follows: Select a high-purity SiO 2 target as the target material, set the sputtering power to 150 W, the sputtering time to 20 min, the sputtering pressure to 1 Pa, and the gas flow rate to 20 mL / min; among them, the sample holder rotates at a speed of 30 r / min; during sputtering, use a film thickness gauge to monitor and control the film thickness in real time to form a high-temperature coating with a thickness of 150 nm; Step 5: Perform oiling, drying, and shaping treatments on the fiber substrate obtained in Step 4 to obtain the high-temperature resistant carbon fiber, where the drying temperature is 135 °C and the shaping temperature is 130 °C.

[0037] Among them, in Step 1, the cleaning solution includes 10 g / L of sodium carbonate, 6 g / L of sodium lignosulfonate, and 2 g / L of sodium dodecyl sulfate.

[0038] In Step 3, the treatment liquid uses ethanol as the solvent, where the mass fraction of tert-butyl glycidyl ether is 4%, the mass fraction of triethoxyvinylsilane is 2.5%, and the mass fraction of fatty alcohol polyoxyethylene ether is 1.3%.

[0039] In Step 5, in the oiling treatment, the addition of the oiling agent accounts for 0.5% of the total mass of the fiber substrate, and amino silicone oil is used.

[0040] Performance Test The high-temperature resistant carbon fibers prepared in Examples 1-3 and Comparative Examples 1-2 were tested. The specific test results are shown in Table 1. The specific test methods are as follows: The interfacial shear strength and tensile strength of the high-temperature resistant carbon fibers prepared in Examples 1-3 and Comparative Examples 1-2 were tested; The high-temperature resistant carbon fibers prepared in Examples 1-3 and Comparative Examples 1-2 were placed in an environment of 1200 °C and heated for 6 h, and after being taken out respectively, their interfacial shear strength was tested.

[0041] Table 1 Performance test result table

[0042] It can be seen from the above table that the temperature resistance of the carbon fiber prepared in this application is increased to above 1200 °C, providing a reliable material basis for the application of high-performance composite materials in extreme environments.

[0043] In this application, by limiting the preparation method of the carbon fiber, a first patting and a second patting are carried out respectively before the sputtering treatment to destroy the oxide layer formed on the surface of the fiber substrate, and a treatment liquid needs to be sprayed before the second patting to improve the activity and adhesion ability of the surface of the fiber substrate, thereby improving the uniformity and bonding strength of the surface coating of the fiber substrate, and increasing the temperature resistance of the prepared carbon fiber from the original 500-800 °C to above 1200 °C, providing a reliable material basis for the application of high-performance composite materials in extreme environments.

[0044] The above is only a preferred embodiment of the present invention, and thus cannot limit the scope of implementation of the present invention. That is, equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the specification should still fall within the scope covered by the patent of the present invention.

Claims

1. A method for preparing high temperature resistant carbon fiber, characterized in that: The specific steps include: Step 1, cleaning the unwound fiber substrate, removing impurities on the surface of the fiber substrate, and then repeatedly rinsing with deionized water, and drying to a moisture content of 15-18%; Step 2, sending the fiber substrate obtained in step 1 into a drying oven, controlling the carbon monoxide mass concentration in the drying oven to be 16-20%, and using airflow to beat the fiber substrate once, the beating time is 10-15 minutes, and the beating force is 30-40Pa / m; Step 3, spraying the treated fiber substrate after step 2 with the treatment liquid, and then sending it into a drying oven, controlling the carbon monoxide mass concentration in the drying oven to be 8-12%, and using airflow to beat the fiber substrate for a second time, the beating time is 10-15 minutes, and the beating force is 18-25 Pa / m; Step 4, installing the dried fiber substrate on the fixed bracket of the wire separator, sending it into the sputtering reaction chamber, first evacuating the reaction chamber to the background vacuum, and then filling it with high-purity inert gas as sputtering gas, the sputtering process parameters are as follows: using SiC target or SiO2 target as the target material, when sputtering SiC target, the sputtering power is 100-500W, and the sputtering time is 10-30min; when sputtering SiO2 target, the sputtering power is 60-120W, and the sputtering time is 10-30min; so as to form a high-temperature coating with a thickness of 150mm on the surface of the fiber substrate; wherein, the sputtering gas pressure is 0.5-5Pa, and the gas flow rate is 5-30mL / min; Step 5, oiling, drying and shaping the fiber substrate obtained in step 4 to obtain the high temperature resistant carbon fiber.

2. The method for preparing a high temperature resistant carbon fiber according to claim 1, characterized in that: In step 3, the treatment liquid uses ethanol as a solvent, wherein the mass fraction of tert-butyl glycidyl ether is 3-5%, the mass fraction of triethoxyvinyl silane is 2-3%, and the mass fraction of fatty alcohol polyoxyethylene ether is 1.2-1.5%.

3. The method for preparing a high temperature resistant carbon fiber according to claim 1, characterized in that: In step 5, after the dried fiber substrate is installed on the fixed bracket of the wire separator, the wire separator driving system is started, and the fiber substrate is evenly separated into multiple independent small filament bundles through the wire separator roller or the yarn separator device to form a plane; during the wire separation process, the wire separator roller drives the fiber bundle to perform periodic reciprocating motion along the axial direction, and at the same time, the moving wire separation fibers are directly introduced into the dynamic transmission device in the sputtering chamber to ensure that the fibers maintain continuous and uniform motion in the sputtering area.

4. The method for preparing a high temperature resistant carbon fiber according to claim 1, characterized in that: In step 5, during the oiling treatment, the oiling agent includes the following raw materials in parts by weight: 50-60 parts of amino silicone oil, 10-15 parts of polyether modified silicone oil, 6-8 parts of polydimethylsiloxane, 3-4 parts of high carbon fatty alcohol polyoxyethylene ether, and 1-2 parts of alkyl alcohol polyoxyethylene ether.

5. The method for preparing a high temperature resistant carbon fiber according to claim 1, characterized in that: In step 1, the cleaning process is as follows: fix the unrolled substrate on the bracket, burn it with a propane flame for 30 seconds, put it into the cleaning liquid after natural cooling, clean it at 50-60°C for 25-35 minutes, rinse it repeatedly with deionized water, and dry it to a moisture content of 15-18%.

6. The method for preparing high temperature resistant carbon fiber according to claim 5, characterized in that: The cleaning solution includes 10 g / L of sodium carbonate, 6 g / L of sodium lignin sulfonate, and 2 g / L of sodium dodecyl sulfate.

7. The method for preparing high temperature resistant carbon fiber according to claim 1, characterized in that: In step 5, the amount of oiling agent added is 0.4-0.6% of the total mass of the fiber substrate.

8. The method for preparing high temperature resistant carbon fiber according to claim 1, characterized in that: In step 5, the drying temperature is 120-150°C.

9. The method for preparing high temperature resistant carbon fiber according to claim 1, characterized in that: In step 5, the setting temperature is 100-150°C.

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