Preparation process of phenolic aldehyde impregnated carbon fiber bar for C / SiC composite material

Abstract

The invention relates to the field of composite materials, in particular to a preparation process of a phenolic aldehyde impregnated carbon fiber bar for a C / SiC composite material, and aims to solve the problems that an existing carbon fiber prepreg easily generates internal defects and residual stress due to weak interface bonding force between carbon fibers and impregnating resin, the residual carbon rate of the impregnating resin is low, and the service life of the carbon fiber prepreg is prolonged. The density and the strength are not good, and the overall performance of the composite material is influenced. According to the preparation process, high-carbon boron-containing cross-linked phenolic resin is adopted to coat epoxy modified carbon fibers, so that the resin is uniformly distributed and fully permeated on the carbon fibers, the mechanical property and the thermal stability of the composite material are improved, and the overall performance of the C / SiC composite material can be remarkably improved; the preparation method can meet the application requirements in high-precision and high-temperature environments, and the process is simple, easy to operate and low in cost, and provides powerful support for industrial production of the C / SiC composite material.

Description

Technical Field

[0001] The invention relates to the field of composite materials, and in particular to a preparation process of a phenolic impregnated carbon fiber rod for a C / SiC composite material. Background Art

[0002] Carbon fiber reinforced silicon carbide (C / SiC) composite materials combine the advantages of carbon fiber and silicon carbide ceramics, and have the advantages of low density, high specific strength, high specific modulus, high temperature resistance, oxidation resistance, good thermal stability and friction and wear resistance. They show great application potential in aerospace thermal protection systems, space optical systems, braking systems, high-temperature heat exchange, engine blades and other fields.

[0003] The preparation process of C / SiC composite material is as follows: first, the carbon fiber is impregnated with resin to form a carbon fiber prepreg material, and then the carbon fiber prepreg material is carbonized at high temperature. The resin is gradually converted into carbon and infiltrated into the carbon fiber in a multi-stage pyrolysis process, and finally combined with the subsequent siliconization process to form SiC continuous phase crystals in the carbon matrix, thereby constructing a C / SiC composite material.

[0004] Therefore, the performance of carbon fiber prepreg plays a key role in the overall performance of C / SiC composites. However, due to the weak interface bonding between carbon fiber and impregnating resin, it is difficult to form a high-density and uniform resin coating on its surface, which is prone to internal defects and residual stress. In addition, the existing impregnating resin has a low residual carbon rate at high temperature, resulting in a large loss of carbon content in the composite material during high-temperature treatment, which in turn leads to poor density and strength, affecting the overall performance of the composite material.

[0005] Therefore, it is of great significance to develop a preparation process for phenolic impregnated carbon fiber rods for C / SiC composites. Summary of the invention

[0006] In order to overcome the above-mentioned technical problems, the purpose of the present invention is to provide a preparation process for phenolic impregnated carbon fiber rods for C / SiC composite materials, which solves the problem that the existing carbon fiber prepreg materials are prone to internal defects and residual stress due to the weak interface bonding force between the carbon fiber and the impregnating resin, and the impregnating resin has a low residual carbon rate at high temperature, which leads to poor density and strength, affecting the overall performance of the composite material.

[0007] The purpose of the present invention can be achieved through the following technical solutions: The preparation process of phenolic impregnated carbon fiber rod for C / SiC composite material comprises the following steps: Step 1: Weigh 5-25 parts of high-carbon boron-containing cross-linked phenolic resin, 3-11 parts of epoxy-modified carbon fiber and 100 parts of anhydrous ethanol according to weight parts, and set aside; Step 2: Add high-carbon boron-containing cross-linked phenolic resin and anhydrous ethanol into a mixer, stir and mix for 20-30 minutes at a temperature of 25-30° C. and a stirring rate of 200-300 r / min to obtain a dipping material; Step three: Add the impregnated material into the impregnation tank, then immerse the epoxy modified carbon fiber in the impregnated material for 20-40 minutes, then take it out and place it in a rod model, dry it at a temperature of 50-55°C for 30-40 minutes, then heat it to 90-95°C and continue to dry it for 30-40 minutes, then heat it to 120-130°C and continue to dry it for 30-40 minutes, then heat it to 170-180°C and continue to dry it for 1-1.5 hours, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0008] As a further solution of the present invention: the high-carbon boron-containing cross-linked phenolic resin is prepared by the following steps: Step A1: Phenol, boric acid and toluene are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 25-30° C. and a stirring rate of 200-300 r / min for 10-15 min, and then the mixture is heated to 150-160° C. and stirred for reaction for 3-4 h, and then heated to 180-190° C. and stirred for reaction for 2-3 h. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation to obtain a triphenylborate monomer; Step A2: Add phenol, naphthol, triphenylborate monomer and formaldehyde solution to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, stir and react for 10-15 minutes at a temperature of 25-30°C and a stirring rate of 200-300r / min, then add sodium hydroxide solution dropwise while stirring until the pH is 9-10, and control the dropping rate to 1-2 drops / s. After the dropwise addition is completed, continue to stir and react for 1-2 hours at a temperature of 50-55°C, then continue to stir and react for 3-5 hours at a temperature of 95-100°C, then add ethylene glycol diglycidyl ether and continue to stir and react for 1-2 hours. After the reaction is completed, cool the reaction product to room temperature, then adjust the pH to 7 with hydrochloric acid solution, and then remove the solvent by rotary evaporation to obtain a high-carbon boron-containing cross-linked phenolic resin.

[0009] As a further solution of the present invention: the usage ratio of the phenol, boric acid and toluene in step A1 is 30-35 mmol:10 mmol:40-50 mL.

[0010] As a further solution of the present invention: the usage ratio of the phenol, naphthol, triphenylborate monomer, formaldehyde solution and ethylene glycol diglycidyl ether in step A2 is 8-10g:3-6g:2.2-3.6g:80-85mL:0.7-2.1g.

[0011] As a further solution of the present invention: the mass fraction of the formaldehyde solution in step A2 is 37%; the mass fraction of the sodium hydroxide solution is 35-40%; and the mass fraction of the hydrochloric acid solution is 20-22%.

[0012] As a further solution of the present invention: the epoxy modified carbon fiber is prepared by the following steps: Step B1: placing the carbon fiber in a tubular furnace, then heating it to 400-420°C at a heating rate of 5-7°C / min, then calcining it at a constant temperature for 1-2h, then cooling it with the furnace, then adding it to a hydrogen peroxide solution, then ultrasonically treating it for 2-3h at an ultrasonic frequency of 30-40kHz, then vacuum filtering it, washing the filter cake with anhydrous ethanol and distilled water for 3-5 times in sequence, then placing it in a vacuum drying oven, and drying it at a temperature of 60-65°C for 3-5h to obtain debonded oxidized carbon fiber; Step B2: Add the degummed oxidized carbon fiber, silane coupling agent KH-560, deionized water and anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer, and ultrasonically disperse for 20-30 minutes at an ultrasonic frequency of 30-40kHz, and then stir and react for 20-30 minutes at a temperature of 25-30°C and a stirring rate of 200-300r / min, and then heat to 60-65°C and continue to stir and react for 4-5 hours. After the reaction is completed, the reaction product is cooled to room temperature, and then vacuum filtered, the filter cake is washed with distilled water for 3-5 times, and then placed in a vacuum drying oven, and dried at a temperature of 60-65°C for 3-5 hours to obtain epoxy modified carbon fiber.

[0013] As a further solution of the present invention: the usage ratio of the carbon fiber and the hydrogen peroxide solution in step B1 is 2g:20-25mL.

[0014] As a further solution of the present invention: the carbon fiber in step B1 is Zhongfu Shenying SYT49S-12K carbon fiber with a length of 25 mm; the mass fraction of the hydrogen peroxide solution is 15-25%.

[0015] As a further solution of the present invention: the usage ratio of the debonded oxidized carbon fiber, silane coupling agent KH-560, deionized water and anhydrous ethanol in step B2 is 5g:1.3-3.9g:85-90mL:10-12mL.

[0016] Beneficial effects of the present invention: The preparation process of the phenolic impregnated carbon fiber rod for C / SiC composite material of the present invention comprises the following steps: adding high-carbon boron-containing cross-linked phenolic resin and anhydrous ethanol into a mixer and stirring and mixing to obtain a sizing material, adding the sizing material into an impregnation tank, then immersing epoxy-modified carbon fiber into the sizing material, then taking out and placing in a rod model for curing and forming, and obtaining the phenolic impregnated carbon fiber rod for C / SiC composite material; in the preparation process, high-carbon boron-containing cross-linked phenolic resin is used to coat the epoxy-modified carbon fiber, thereby achieving uniform distribution and full penetration of the resin on the carbon fiber, improving the mechanical properties and thermal stability of the composite material, and being able to significantly improve the overall performance of the C / SiC composite material, so that the C / SiC composite material can meet the application requirements in high-precision and high-temperature environments, and expand its application scope; the process is simple, easy to operate, and has low cost, and provides strong support for the industrialized production of the C / SiC composite material; In the process of preparing phenolic impregnated carbon fiber rods, a high-carbon boron-containing cross-linked phenolic resin is first prepared. First, phenol and boric acid are reacted, and the phenolic hydroxyl group on the phenol reacts with the boric acid group on the boric acid to form a borate ester structure and introduce phenyl to obtain a triphenyl borate monomer. Then, phenol, naphthol, triphenyl borate monomer and formaldehyde are used as polymerization monomers to carry out a condensation reaction under alkaline conditions to form a phenolic resin structure, and the hydroxyl group in the phenolic resin structure is reacted with the epoxy group in ethylene glycol diglycidol to achieve cross-linking between the phenolic resin polymers to obtain a high-carbon boron-containing cross-linked phenolic resin. Formaldehyde resin; the high-carbon boron-containing cross-linked phenolic resin increases the carbon content of its molecular structure by introducing naphthalene rings, and the introduction of boron atoms can replace some CO bonds with weaker bond energy with BOC bonds with large bond energy, thereby improving thermal stability and reducing high-temperature decomposition. At the same time, a boron oxide protective layer is generated at high temperature to inhibit oxidation and form a branched structure. The cross-linking density is significantly increased under the joint action of ethylene glycol diglycidol, so that the carbon fiber can be evenly and densely coated, a strong interface bond can be formed, the mechanical properties of the composite material are improved, and decomposition is inhibited, so that the phenolic resin has a higher residual carbon rate at high temperature; In the process of preparing phenolic impregnated carbon fiber rods, an epoxy-modified carbon fiber is also prepared. First, calcination treatment is used to remove surface impurities. Then, a large number of oxygen-containing active groups are grafted after hydrogen peroxide oxidation treatment to obtain degumming oxidized carbon fiber. Then, the degumming oxidized carbon fiber and silane coupling agent KH-560 are reacted. The siloxane on the silane coupling agent KH-560 is hydrolyzed to form silanol and grafted to the surface of the degumming oxidized carbon fiber. At the same time, a large number of epoxy groups are introduced to obtain epoxy-modified carbon fiber; the modified carbon fiber has good compatibility with high-carbon boron-containing cross-linked phenolic resin, so that the carbon fiber can be evenly distributed in the high-carbon boron-containing cross-linked phenolic resin, thereby improving the overall quality and reliability of the rod, and the epoxy group is used to react with the hydroxyl group in the high-carbon boron-containing cross-linked phenolic resin to connect the two in the form of chemical bonds, thereby forming a strong interface bond. This interface bond can effectively transfer stress and improve the mechanical properties of the composite material. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1: This example is a preparation process for a phenolic impregnated carbon fiber rod for a C / SiC composite material, comprising the following steps: Step S1: 30 mmol phenol, 10 mmol boric acid and 40 mL toluene are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at 25° C. and a stirring rate of 200 r / min for 10 min, and then the mixture is heated to 150° C. and stirred for reaction for 3 h, and then heated to 180° C. and stirred for reaction for 2 h. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation to obtain a triphenylborate monomer; Step S2: 8 g of phenol, 3 g of naphthol, 2.2 g of triphenylborate monomer and 80 mL of 37% formaldehyde solution are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and stirred for reaction at a temperature of 25° C. and a stirring rate of 200 r / min for 10 min, and then a 35% sodium hydroxide solution is added dropwise while stirring until the pH is 9, and the dropping rate is controlled to be 1 drop / s. After the dropwise addition is completed, the temperature is raised to 50° C. and the stirring reaction is continued for 1 h, and then the temperature is raised to 95° C. and the stirring reaction is continued for 3 h, and then 0.7 g of ethylene glycol diglycidyl ether is added and the stirring reaction is continued for 1 h. After the reaction is completed, the reaction product is cooled to room temperature, and then adjusted to pH 7 with a 20% hydrochloric acid solution, and then the solvent is removed by rotary evaporation to obtain a high-carbon boron-containing cross-linked phenolic resin; Step S3: 2 g of Zhongfu Shenying SYT49S-12K carbon fiber with a length of 25 mm was placed in a tubular furnace, and then heated to 400°C at a heating rate of 5°C / min, and then calcined at a constant temperature for 1 hour, and then cooled with the furnace, and then added to 20 mL of a 15% mass fraction hydrogen peroxide solution, and then ultrasonically treated for 2 hours at an ultrasonic frequency of 30 kHz, and then vacuum filtered, and the filter cake was washed with anhydrous ethanol and distilled water for 3 times in sequence, and then placed in a vacuum drying oven, and dried at a temperature of 60°C for 3 hours to obtain debonded oxidized carbon fiber; Step S4: 5 g of degummed oxidized carbon fiber, 1.3 g of silane coupling agent KH-560, 85 mL of deionized water and 10 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer and a thermometer, and ultrasonically dispersed for 20 min at an ultrasonic frequency of 30 kHz, and then stirred for reaction at a temperature of 25° C. and a stirring rate of 200 r / min for 20 min, and then heated to 60° C. and continued to stir for 4 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filter cake was washed with distilled water 3 times, and then placed in a vacuum drying oven and dried at a temperature of 60° C. for 3 h to obtain epoxy modified carbon fiber; Step S5: weigh 5 parts of high-carbon boron-containing cross-linked phenolic resin, 3 parts of epoxy-modified carbon fibers and 100 parts of anhydrous ethanol according to weight parts for later use; Step S6: adding high-carbon boron-containing cross-linked phenolic resin and anhydrous ethanol into a mixer, stirring and mixing for 20 minutes at a temperature of 25° C. and a stirring rate of 200 r / min to obtain a dipping material; Step S7: Add the impregnated material into the impregnation tank, then immerse the epoxy modified carbon fiber in the impregnated material for 20 minutes, then take it out and place it in a rod model, dry it at a temperature of 50°C for 30 minutes, then heat it to 90°C and continue to dry it for 30 minutes, then heat it to 120°C and continue to dry it for 30 minutes, then heat it to 170°C and continue to dry it for 1 hour, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0019] Example 2: This example is a preparation process for a phenolic impregnated carbon fiber rod for a C / SiC composite material, comprising the following steps: Step S1: 32 mmol phenol, 10 mmol boric acid and 45 mL toluene were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred at 28° C. and a stirring rate of 250 r / min for 12 min, and then the mixture was heated to 155° C. and stirred for 3.5 h. The mixture was heated to 185° C. and stirred for 2.5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation to obtain a triphenylborate monomer. Step S2: 9 g of phenol, 4.5 g of naphthol, 2.9 g of triphenylborate monomer and 82 mL of 37% formaldehyde solution were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and stirred for reaction at a temperature of 28° C. and a stirring rate of 250 r / min for 12 min, and then a 38% sodium hydroxide solution was added dropwise while stirring until the pH was 9.5, and the dropping rate was controlled to be 1 drop / s. After the dropwise addition was completed, the temperature was raised to 52° C. and the stirring reaction was continued for 1.5 h, and then the temperature was raised to 98° C. and the stirring reaction was continued for 4 h, and then 1.4 g of ethylene glycol diglycidyl ether was added and the stirring reaction was continued for 1.5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then adjusted to pH 7 with a 21% hydrochloric acid solution, and then the solvent was removed by rotary evaporation to obtain a high-carbon boron-containing cross-linked phenolic resin; Step S3: 2 g of Zhongfu Shenying SYT49S-12K carbon fiber with a length of 25 mm was placed in a tubular furnace, and then heated to 410°C at a heating rate of 6°C / min, and then calcined at a constant temperature for 1.5 hours, and then cooled with the furnace, and then added to 22 mL of a 20% hydrogen peroxide solution, and then ultrasonically treated for 2.5 hours at an ultrasonic frequency of 35 kHz, and then vacuum filtered, and the filter cake was washed with anhydrous ethanol and distilled water for 4 times in sequence, and then placed in a vacuum drying oven, and dried at a temperature of 62°C for 4 hours to obtain debonded oxidized carbon fiber; Step S4: 5 g of degummed oxidized carbon fiber, 2.6 g of silane coupling agent KH-560, 88 mL of deionized water and 11 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer and a thermometer, and ultrasonically dispersed for 25 min at an ultrasonic frequency of 35 kHz, and then stirred for reaction at a temperature of 28 ° C and a stirring rate of 250 r / min for 25 min, and then heated to 62 ° C and continued to stir for 4.5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filter cake was washed with distilled water 4 times, and then placed in a vacuum drying oven and dried at a temperature of 62 ° C for 4 h to obtain epoxy modified carbon fiber; Step S5: weigh 15 parts of high-carbon boron-containing cross-linked phenolic resin, 7 parts of epoxy-modified carbon fibers and 100 parts of anhydrous ethanol according to weight parts for later use; Step S6: adding high-carbon boron-containing cross-linked phenolic resin and anhydrous ethanol into a mixer, stirring and mixing for 25 minutes at a temperature of 28° C. and a stirring rate of 250 r / min to obtain a dipping material; Step S7: Add the impregnated material into the impregnation tank, then immerse the epoxy modified carbon fiber in the impregnated material for 30 minutes, then take it out and place it in a rod model, dry it at a temperature of 52°C for 35 minutes, then heat it to 92°C and continue drying it for 35 minutes, then heat it to 125°C and continue drying it for 35 minutes, then heat it to 175°C and continue drying it for 1 hour, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0020] Example 3: This example is a preparation process for a phenolic impregnated carbon fiber rod for a C / SiC composite material, comprising the following steps: Step S1: 35 mmol phenol, 10 mmol boric acid and 50 mL toluene are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at 30° C. and a stirring rate of 300 r / min for 15 min, and then the mixture is heated to 160° C. and stirred for reaction for 4 h, and then heated to 190° C. and stirred for reaction for 3 h. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation to obtain a triphenylborate monomer; Step S2: 10 g of phenol, 6 g of naphthol, 3.6 g of triphenylborate monomer and 85 mL of 37% formaldehyde solution are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and stirred for 15 min at a temperature of 30° C. and a stirring rate of 300 r / min, and then a 40% sodium hydroxide solution is added dropwise while stirring until the pH is 10, and the dropping rate is controlled to be 2 drops / s. After the dropwise addition is completed, the temperature is raised to 55° C. and the stirring reaction is continued for 2 h, and then the temperature is raised to 100° C. and the stirring reaction is continued for 5 h, and then 2.1 g of ethylene glycol diglycidyl ether is added and the stirring reaction is continued for 2 h. After the reaction is completed, the reaction product is cooled to room temperature, and then adjusted to pH 7 with a 22% hydrochloric acid solution, and then the solvent is removed by rotary evaporation to obtain a high-carbon boron-containing cross-linked phenolic resin; Step S3: 2 g of Zhongfu Shenying SYT49S-12K carbon fiber with a length of 25 mm was placed in a tubular furnace, and then heated to 420°C at a heating rate of 7°C / min, and then calcined at a constant temperature for 2 hours, and then cooled with the furnace, and then added to 25 mL of a 25% hydrogen peroxide solution, and then ultrasonically treated for 3 hours at an ultrasonic frequency of 40 kHz, and then vacuum filtered, and the filter cake was washed with anhydrous ethanol and distilled water for 5 times in sequence, and then placed in a vacuum drying oven, and dried at a temperature of 65°C for 5 hours to obtain debonded oxidized carbon fiber; Step S4: 5 g of debonded oxidized carbon fiber, 3.9 g of silane coupling agent KH-560, 90 mL of deionized water and 12 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer and a thermometer, and ultrasonically dispersed for 30 min at an ultrasonic frequency of 40 kHz, and then stirred for reaction at a temperature of 30° C. and a stirring rate of 300 r / min for 30 min, and then heated to 65° C. and continued to stir for 5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filter cake was washed with distilled water 5 times, and then placed in a vacuum drying oven and dried at a temperature of 65° C. for 5 h to obtain epoxy modified carbon fiber; Step S5: weigh 25 parts of high-carbon boron-containing cross-linked phenolic resin, 11 parts of epoxy-modified carbon fibers and 100 parts of anhydrous ethanol according to weight parts for later use; Step S6: adding high-carbon boron-containing cross-linked phenolic resin and anhydrous ethanol into a mixer, stirring and mixing at a temperature of 30° C. and a stirring rate of 300 r / min for 30 minutes to obtain a dipping material; Step S7: Add the impregnated material into the impregnation tank, then immerse the epoxy modified carbon fiber in the impregnated material for 40 minutes, then take it out and place it in a rod model, dry it at a temperature of 55°C for 40 minutes, then heat it to 95°C and continue to dry it for 40 minutes, then heat it to 130°C and continue to dry it for 40 minutes, then heat it to 180°C and continue to dry it for 1.5 hours, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0021] Comparative Example 1: This comparative example is a preparation process of a phenolic impregnated carbon fiber rod for a C / SiC composite material, comprising the following steps: Step S1: 10 g of phenol and 85 mL of a 37% formaldehyde solution are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and the mixture is stirred for reaction at a temperature of 30° C. and a stirring rate of 300 r / min for 15 min, and then a 40% sodium hydroxide solution is added dropwise while stirring until the pH is 10, and the dropping rate is controlled to be 2 drops / s. After the addition is completed, the mixture is heated to 55° C. and stirred for reaction for 2 h, and then heated to 100° C. and stirred for reaction for 5 h. After the reaction is completed, the reaction product is cooled to room temperature, and then adjusted to pH 7 with a 22% hydrochloric acid solution, and then the solvent is removed by rotary evaporation to obtain a phenolic resin; Step S2: Weigh 25 parts of phenolic resin, 11 parts of SYT49S-12K carbon fiber with a length of 25 mm and 100 parts of anhydrous ethanol according to weight parts for later use; Step S3: adding phenolic resin and anhydrous ethanol into a mixer, stirring and mixing for 30 minutes at a temperature of 30° C. and a stirring rate of 300 r / min to obtain a dipping material; Step S4: Add the impregnated material into the impregnation tank, and then immerse the Zhongfu Shenying SYT49S-12K carbon fiber in the impregnated material for 40 minutes, then take it out and place it in a rod model, dry it at a temperature of 55°C for 40 minutes, then heat it to 95°C and continue to dry it for 40 minutes, then heat it to 130°C and continue to dry it for 40 minutes, then heat it to 180°C and continue to dry it for 1.5 hours, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0022] Comparative Example 2: This comparative example is a preparation process of a phenolic impregnated carbon fiber rod for a C / SiC composite material, comprising the following steps: Step S1: 10 g of phenol, 6 g of naphthol and 85 mL of a 37% formaldehyde solution are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and stirred for 15 min at a temperature of 30° C. and a stirring rate of 300 r / min, and then a 40% sodium hydroxide solution is added dropwise while stirring until the pH is 10, and the dropping rate is controlled to be 2 drops / s. After the dropwise addition is completed, the temperature is raised to 55° C. and the stirring reaction is continued for 2 h, and then the temperature is raised to 100° C. and the stirring reaction is continued for 5 h. After the reaction is completed, the reaction product is cooled to room temperature, and then adjusted to pH 7 with a 22% hydrochloric acid solution, and then the solvent is removed by rotary evaporation to obtain a high-carbon phenolic resin; Step S2: Weigh 25 parts of high-carbon phenolic resin, 11 parts of 25 mm-long Zhongfu Shenying SYT49S-12K carbon fiber and 100 parts of anhydrous ethanol according to weight, and set aside; Step S3: adding high carbon phenolic resin and anhydrous ethanol into a mixer, stirring and mixing for 30 minutes at a temperature of 30° C. and a stirring rate of 300 r / min to obtain a dipping material; Step S4: Add the impregnated material into the impregnation tank, and then immerse the Zhongfu Shenying SYT49S-12K carbon fiber in the impregnated material for 40 minutes, then take it out and place it in a rod model, dry it at a temperature of 55°C for 40 minutes, then heat it to 95°C and continue to dry it for 40 minutes, then heat it to 130°C and continue to dry it for 40 minutes, then heat it to 180°C and continue to dry it for 1.5 hours, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0023] Comparative Example 3: This comparative example is a preparation process of a phenolic impregnated carbon fiber rod for a C / SiC composite material, comprising the following steps: Step S1: 35 mmol phenol, 10 mmol boric acid and 50 mL toluene are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at 30° C. and a stirring rate of 300 r / min for 15 min, and then the mixture is heated to 160° C. and stirred for reaction for 4 h, and then heated to 190° C. and stirred for reaction for 3 h. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation to obtain a triphenylborate monomer; Step S2: 10 g of phenol, 6 g of naphthol, 3.6 g of triphenylborate monomer and 85 mL of 37% formaldehyde solution were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and stirred for 15 min at a temperature of 30° C. and a stirring rate of 300 r / min, and then a 40% sodium hydroxide solution was added dropwise while stirring until the pH was 10, and the dropping rate was controlled to be 2 drops / s. After the dropwise addition was completed, the temperature was raised to 55° C. and the stirring reaction was continued for 2 h, and then the temperature was raised to 100° C. and the stirring reaction was continued for 5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then adjusted to pH 7 with a 22% hydrochloric acid solution, and then the solvent was removed by rotary evaporation to obtain a high-carbon boron-containing phenolic resin; Step S3: Weigh 25 parts of high-carbon boron-containing phenolic resin, 11 parts of SYT49S-12K carbon fiber with a length of 25 mm, and 100 parts of anhydrous ethanol according to weight, and set aside; Step S4: adding high-carbon boron-containing phenolic resin and anhydrous ethanol into a mixer, stirring and mixing for 30 minutes at a temperature of 30° C. and a stirring rate of 300 r / min to obtain a dipping material; Step S5: Add the impregnated material into the impregnation tank, and then immerse the Zhongfu Shenying SYT49S-12K carbon fiber in the impregnated material for 40 minutes, then take it out and place it in a rod model, dry it at a temperature of 55°C for 40 minutes, then heat it to 95°C and continue to dry it for 40 minutes, then heat it to 130°C and continue to dry it for 40 minutes, then heat it to 180°C and continue to dry it for 1.5 hours, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0024] Comparative Example 4: This comparative example is a preparation process of a phenolic impregnated carbon fiber rod for a C / SiC composite material, comprising the following steps: Step S1: 35 mmol phenol, 10 mmol boric acid and 50 mL toluene are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at 30° C. and a stirring rate of 300 r / min for 15 min, and then the mixture is heated to 160° C. and stirred for reaction for 4 h, and then heated to 190° C. and stirred for reaction for 3 h. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation to obtain a triphenylborate monomer; Step S2: 10 g of phenol, 6 g of naphthol, 3.6 g of triphenylborate monomer and 85 mL of 37% formaldehyde solution are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and stirred for 15 min at a temperature of 30° C. and a stirring rate of 300 r / min, and then a 40% sodium hydroxide solution is added dropwise while stirring until the pH is 10, and the dropping rate is controlled to be 2 drops / s. After the dropwise addition is completed, the temperature is raised to 55° C. and the stirring reaction is continued for 2 h, and then the temperature is raised to 100° C. and the stirring reaction is continued for 5 h, and then 2.1 g of ethylene glycol diglycidyl ether is added and the stirring reaction is continued for 2 h. After the reaction is completed, the reaction product is cooled to room temperature, and then adjusted to pH 7 with a 22% hydrochloric acid solution, and then the solvent is removed by rotary evaporation to obtain a high-carbon boron-containing cross-linked phenolic resin; Step S3: Weigh 25 parts of high-carbon boron-containing cross-linked phenolic resin, 11 parts of 25 mm-long Zhongfu Shenying SYT49S-12K carbon fiber, and 100 parts of anhydrous ethanol according to weight parts for later use; Step S4: adding high-carbon boron-containing cross-linked phenolic resin and anhydrous ethanol into a mixer, stirring and mixing at a temperature of 30° C. and a stirring rate of 300 r / min for 30 minutes to obtain a dipping material; Step S5: Add the impregnated material into the impregnation tank, and then immerse the Zhongfu Shenying SYT49S-12K carbon fiber in the impregnated material for 40 minutes, then take it out and place it in a rod model, dry it at a temperature of 55°C for 40 minutes, then heat it to 95°C and continue to dry it for 40 minutes, then heat it to 130°C and continue to dry it for 40 minutes, then heat it to 180°C and continue to dry it for 1.5 hours, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0025] Comparative Example 5: This comparative example is a preparation process of a phenolic impregnated carbon fiber rod for a C / SiC composite material, comprising the following steps: Step S1: 35 mmol phenol, 10 mmol boric acid and 50 mL toluene are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at 30° C. and a stirring rate of 300 r / min for 15 min, and then the mixture is heated to 160° C. and stirred for reaction for 4 h, and then heated to 190° C. and stirred for reaction for 3 h. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation to obtain a triphenylborate monomer; Step S2: 10 g of phenol, 6 g of naphthol, 3.6 g of triphenylborate monomer and 85 mL of 37% formaldehyde solution are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and stirred for 15 min at a temperature of 30° C. and a stirring rate of 300 r / min, and then a 40% sodium hydroxide solution is added dropwise while stirring until the pH is 10, and the dropping rate is controlled to be 2 drops / s. After the dropwise addition is completed, the temperature is raised to 55° C. and the stirring reaction is continued for 2 h, and then the temperature is raised to 100° C. and the stirring reaction is continued for 5 h, and then 2.1 g of ethylene glycol diglycidyl ether is added and the stirring reaction is continued for 2 h. After the reaction is completed, the reaction product is cooled to room temperature, and then adjusted to pH 7 with a 22% hydrochloric acid solution, and then the solvent is removed by rotary evaporation to obtain a high-carbon boron-containing cross-linked phenolic resin; Step S3: 2 g of Zhongfu Shenying SYT49S-12K carbon fiber with a length of 25 mm was placed in a tubular furnace, and then heated to 420°C at a heating rate of 7°C / min, and then calcined at a constant temperature for 2 hours, and then cooled with the furnace, and then added to 25 mL of a 25% hydrogen peroxide solution, and then ultrasonically treated for 3 hours at an ultrasonic frequency of 40 kHz, and then vacuum filtered, and the filter cake was washed with anhydrous ethanol and distilled water for 5 times in sequence, and then placed in a vacuum drying oven, and dried at a temperature of 65°C for 5 hours to obtain debonded oxidized carbon fiber; Step S4: weigh 25 parts of high-carbon boron-containing cross-linked phenolic resin, 11 parts of debonded oxidized carbon fibers, and 100 parts of anhydrous ethanol according to weight parts for later use; Step S5: adding high-carbon boron-containing cross-linked phenolic resin and anhydrous ethanol into a mixer, stirring and mixing at a temperature of 30° C. and a stirring rate of 300 r / min for 30 minutes to obtain a dipping material; Step S6: Add the impregnated material into the impregnation tank, then immerse the debonded oxidized carbon fiber in the impregnated material for 40 minutes, then take it out and place it in a rod model, dry it at a temperature of 55°C for 40 minutes, then heat it to 95°C and continue to dry it for 40 minutes, then heat it to 130°C and continue to dry it for 40 minutes, then heat it to 180°C and continue to dry it for 1.5 hours, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0026] Comparative Example 6: This comparative example is a preparation process of a phenolic impregnated carbon fiber rod for a C / SiC composite material, comprising the following steps: Step S1: 10 g of phenol and 85 mL of a 37% formaldehyde solution are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and the mixture is stirred for reaction at a temperature of 30° C. and a stirring rate of 300 r / min for 15 min, and then a 40% sodium hydroxide solution is added dropwise while stirring until the pH is 10, and the dropping rate is controlled to be 2 drops / s. After the addition is completed, the mixture is heated to 55° C. and stirred for reaction for 2 h, and then heated to 100° C. and stirred for reaction for 5 h. After the reaction is completed, the reaction product is cooled to room temperature, and then adjusted to pH 7 with a 22% hydrochloric acid solution, and then the solvent is removed by rotary evaporation to obtain a phenolic resin; Step S2: 2 g of Zhongfu Shenying SYT49S-12K carbon fiber with a length of 25 mm was placed in a tubular furnace, and then heated to 420°C at a heating rate of 7°C / min, and then calcined at a constant temperature for 2 hours, and then cooled with the furnace, and then added to 25 mL of a 25% hydrogen peroxide solution, and then ultrasonically treated for 3 hours at an ultrasonic frequency of 40 kHz, and then vacuum filtered, and the filter cake was washed with anhydrous ethanol and distilled water for 5 times in sequence, and then placed in a vacuum drying oven, and dried at a temperature of 65°C for 5 hours to obtain debonded oxidized carbon fiber; Step S3: 5 g of debonded oxidized carbon fiber, 3.9 g of silane coupling agent KH-560, 90 mL of deionized water and 12 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer and a thermometer, and ultrasonically dispersed for 30 min at an ultrasonic frequency of 40 kHz, and then stirred for reaction at a temperature of 30° C. and a stirring rate of 300 r / min for 30 min, and then heated to 65° C. and continued to stir for reaction for 5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filter cake was washed with distilled water 5 times, and then placed in a vacuum drying oven and dried at a temperature of 65° C. for 5 h to obtain epoxy modified carbon fiber; Step S4: weigh 25 parts of phenolic resin, 11 parts of epoxy-modified carbon fibers and 100 parts of anhydrous ethanol according to weight and set aside; Step S5: adding phenolic resin and anhydrous ethanol into a mixer, stirring and mixing for 30 minutes at a temperature of 30° C. and a stirring rate of 300 r / min to obtain a dipping material; Step S6: Add the impregnated material into the impregnation tank, then immerse the epoxy modified carbon fiber in the impregnated material for 40 minutes, then take it out and place it in a rod model, dry it at a temperature of 55°C for 40 minutes, then heat it to 95°C and continue to dry it for 40 minutes, then heat it to 130°C and continue to dry it for 40 minutes, then heat it to 180°C and continue to dry it for 1.5 hours, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

[0027] The properties of the phenolic impregnated carbon fiber rods for C / SiC composite materials of Examples 1-3 and Comparative Examples 1-6 were tested: Test tensile properties according to GB / T-1447-2005; Test compression performance according to GB / T-1448-2005; The temperature and carbon residue rate of the sample when the mass decreased by 5% during the heating process were tested using a NETZSCH STA 409 CD synchronous thermal analyzer in a nitrogen environment with a flow rate of 25 mL / min and a heating rate of 10°C / min from room temperature to 1000°C.

[0028] .

[0029] Referring to the data in the above table, based on the comparison between Examples 1-3 and Comparative Examples 1-6, it can be known that the phenolic impregnated carbon fiber rod for C / SiC composite material of the present application has excellent mechanical properties, heat resistance and high residual carbon.

[0030] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0031] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined in this application, they shall all fall within the protection scope of the present invention.

Claims

1. A process for preparing phenolic impregnated carbon fiber rods for C / SiC composite materials, characterized in that: The following steps are involved: Step 1: Weigh 5-25 parts of high-carbon boron-containing cross-linked phenolic resin, 3-11 parts of epoxy-modified carbon fiber and 100 parts of anhydrous ethanol according to weight parts, and set aside; Step 2: Add high-carbon boron-containing cross-linked phenolic resin and anhydrous ethanol into a mixer, stir and mix for 20-30 minutes at a temperature of 25-30° C. and a stirring rate of 200-300 r / min to obtain a dipping material; Step three: Add the impregnated material into the impregnation tank, then immerse the epoxy modified carbon fiber in the impregnated material for 20-40 minutes, then take it out and place it in a rod model, dry it at a temperature of 50-55°C for 30-40 minutes, then heat it to 90-95°C and continue to dry it for 30-40 minutes, then heat it to 120-130°C and continue to dry it for 30-40 minutes, then heat it to 170-180°C and continue to dry it for 1-1.5 hours, and then cool it to room temperature to obtain a phenolic impregnated carbon fiber rod for C / SiC composite materials.

2. The process for preparing phenolic impregnated carbon fiber rods for C / SiC composite materials according to claim 1, characterized in that: The high-carbon boron-containing cross-linked phenolic resin is prepared by the following steps: Step A1: stirring phenol, boric acid and toluene for reaction, cooling the reaction product after the reaction is completed, and then rotary evaporating to obtain triphenyl borate monomer; Step A2: Stir phenol, naphthol, triphenylborate monomer and formaldehyde solution for reaction, then add sodium hydroxide solution dropwise while stirring, continue stirring the reaction after the addition is complete, then add ethylene glycol diglycidyl ether and continue stirring the reaction, after the reaction is completed, cool the reaction product, then adjust the pH with hydrochloric acid solution, and then rotary evaporate to obtain a high-carbon boron-containing cross-linked phenolic resin.

3. The process for preparing phenolic impregnated carbon fiber rods for C / SiC composite materials according to claim 2, characterized in that: The usage ratio of the phenol, boric acid and toluene in step A1 is 30-35 mmol:10 mmol:40-50 mL.

4. The process for preparing phenolic impregnated carbon fiber rods for C / SiC composite materials according to claim 2, characterized in that: The usage ratio of the phenol, naphthol, triphenylborate monomer, formaldehyde solution and ethylene glycol diglycidyl ether in step A2 is 8-10 g: 3-6 g: 2.2-3.6 g: 80-85 mL: 0.7-2.1 g.

5. The process for preparing phenolic impregnated carbon fiber rods for C / SiC composite materials according to claim 2, characterized in that: The mass fraction of the formaldehyde solution in step A2 is 37%; the mass fraction of the sodium hydroxide solution is 35-40%; and the mass fraction of the hydrochloric acid solution is 20-22%.

6. The process for preparing phenolic impregnated carbon fiber rods for C / SiC composite materials according to claim 1, characterized in that: The epoxy modified carbon fiber is prepared by the following steps: Step B1: placing the carbon fiber in a tubular furnace for constant temperature calcination, then cooling with the furnace, then adding it to a hydrogen peroxide solution for ultrasonic treatment, then vacuum filtering, washing and drying the filter cake to obtain debonded oxidized carbon fiber; Step B2: ultrasonically disperse the debonded oxidized carbon fiber, silane coupling agent KH-560, deionized water and anhydrous ethanol, and then stir to react. After the reaction is completed, cool the reaction product, and then vacuum filter it, wash and dry the filter cake to obtain epoxy modified carbon fiber.

7. The process for preparing phenolic impregnated carbon fiber rods for C / SiC composite materials according to claim 6, characterized in that: The usage ratio of the carbon fiber and the hydrogen peroxide solution in step B1 is 2 g: 20-25 mL.

8. The process for preparing phenolic impregnated carbon fiber rods for C / SiC composite materials according to claim 6, characterized in that: The carbon fiber in step B1 is Zhongfu Shenying SYT49S-12K carbon fiber with a length of 25 mm; the mass fraction of the hydrogen peroxide solution is 15-25%.

9. The process for preparing phenolic impregnated carbon fiber rods for C / SiC composite materials according to claim 6, characterized in that: The usage ratio of the debonded oxidized carbon fiber, silane coupling agent KH-560, deionized water and anhydrous ethanol in step B2 is 5g:1.3-3.9g:85-90mL:10-12mL.