High-heat-resistance carbon fiber reinforced resin-based composite material and preparation method thereof

Abstract

The invention provides a high-heat-resistance carbon fiber reinforced resin-based composite material and a preparation method thereof, and relates to the technical field of high-heat-resistance carbon fiber reinforced resin-based composites.The composite material is prepared from, by weight, 30%-70% of carbon fibers, 25%-65% of high-heat-resistance thermosetting resin and 0.1%-5% of additives. The carbon fibers are subjected to chemical and physical combined surface treatment, so that the interface bonding performance between the carbon fibers and the high-heat-resistance thermosetting resin is effectively improved. Through chemical treatment of a coupling agent and physical treatment of plasma, the activity of the surface of the carbon fiber is enhanced, and the carbon fiber can be more firmly combined with resin. Through the improvement, the mechanical strength of the composite material in a high-temperature environment is remarkably improved, and the problems of layering and interface separation possibly occurring in long-term high-temperature exposure are reduced, so that the structural stability of the material is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of high heat-resistant carbon fiber reinforced resin-based composite materials, and in particular to a high heat-resistant carbon fiber reinforced resin-based composite material and a preparation method thereof. Background Art

[0002] Carbon fiber reinforced resin-based composites are widely used in high-tech fields such as aerospace, automobile manufacturing, energy, and electronics due to their high specific strength, light weight, and corrosion resistance. They show unique advantages, especially in situations where high strength and light weight are required. In recent years, with the increasing demand for high-temperature industrial applications, the performance of carbon fiber composites in high-temperature environments has become a research focus. However, traditional carbon fiber reinforced resin-based composites show some problems that cannot be ignored in long-term high-temperature environments, such as insufficient interfacial adhesion, poor dimensional stability, and low pyrolysis temperature, which limit their wide application under extreme high temperature conditions. Traditional carbon fiber composites mainly use ordinary thermosetting resins (such as epoxy resins) as matrix materials, and their glass transition temperatures are low, usually between 150°C and 200°C. When used at higher temperatures, they soften or decompose, resulting in a decrease in material performance. In addition, the surface activity of carbon fiber is low, lacks effective bonding with the resin, and has weak interfacial adhesion, which directly affects the overall mechanical properties and heat resistance of the composite material. In order to meet the needs in high temperature environments, researchers have gradually developed some high heat-resistant resins, such as polyimide resins, bismaleimide resins and benzoxazine resins, which can maintain excellent performance at higher temperatures. However, simply replacing the resin material is not enough to significantly improve the overall performance of the composite material, especially in terms of dimensional stability, creep resistance and aging resistance in long-term high temperature environments. Therefore, improving the surface treatment process of carbon fiber, optimizing the preparation method of composite materials, and improving the comprehensive performance of materials under extreme conditions have become important research directions in the current technical field;

[0003] In the preparation of traditional carbon fiber reinforced resin-based composite materials, the interface treatment of carbon fiber is often not perfect, resulting in weak bonding between fiber and resin, especially in high temperature environment, the bonding between carbon fiber and resin decreases, and delamination and detachment are prone to occur. Traditional surface treatment methods mainly rely on simple chemical treatments, such as acid and alkali washing or oxidation treatment. Although these methods can improve the bonding performance to a certain extent, the effect is limited and cannot meet the higher requirements of interface strength in high temperature environment. In addition, in the mixing process of resin and fiber, the traditional process does not accurately control the temperature and pressure, especially the insufficient regulation of resin viscosity, resulting in the carbon fiber cannot be uniformly infiltrated, and the internal structure of the composite material has defects. Prepreg is prone to bubbles or uneven distribution during the molding process, which directly affects the density and strength of the material, making it more prone to creep or deformation in high temperature environment. In addition, the traditional compression molding and curing process lacks precise control of temperature and pressure, resulting in uneven temperature distribution inside the composite material, which is easy to form internal stress, thereby affecting the stability and service life of the material. During the high temperature curing process, if the heating rate or temperature is not properly controlled, excessive thermal stress may be generated inside the composite material, resulting in material performance degradation or cracks. Especially in terms of flame retardancy, the flame retardants added to traditional composite materials have limited effects, and the risk of combustion at high temperatures is relatively high, making it difficult to meet the strict requirements for flame retardancy and high-temperature safety in the fields of aerospace, automobiles, etc. These technical deficiencies have severely limited the application of traditional carbon fiber reinforced resin-based composite materials under high temperature conditions, especially in long-term high temperature exposure and high fire risk situations, which need to be optimized and improved. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problems raised in the above background technology.

[0005] The present invention adopts the following technical scheme: a high heat-resistant carbon fiber reinforced resin-based composite material, the composite material includes the following components in weight percentage: 30% to 70% carbon fiber, 25% to 65% high heat-resistant thermosetting resin, and 0.1% to 5% additives, wherein the additive is at least one of a heat-resistant agent, a toughening agent, an antioxidant, a flame retardant or a moisture-proof agent, the carbon fiber is surface-treated to improve its interfacial bonding performance with the thermosetting resin, the composite material has a thermal decomposition temperature of at least 350°C, and maintains more than 90% of the mechanical strength at this temperature; the composite material is suitable for long-term exposure to a high temperature environment of 300°C to 450°C, and exhibits excellent dimensional stability, aging resistance and creep resistance under such high temperature conditions.

[0006] Preferably, the high heat-resistant thermosetting resin is selected from polyimide resin, bismaleimide resin, benzoxazine resin, polyaryletherketone resin or a combination thereof, wherein the glass transition temperature of the polyimide resin is not less than 300°C, the curing temperature range of the bismaleimide resin is 180°C to 250°C, the benzoxazine resin forms a highly cross-linked network structure after curing, and the polyaryletherketone resin has excellent chemical stability and radiation resistance; the resin is treated by at least one preliminary curing and one high-temperature secondary curing to form a highly cross-linked molecular structure, thereby enhancing the high temperature resistance, creep resistance and oxidation resistance of the composite material, and is suitable for long-term use in high temperature environments. Here, by using high heat-resistant resins such as polyimide, bismaleimide, and benzoxazine resin, the creep resistance and oxidation resistance of the composite material in a high temperature environment are enhanced. These resins form a highly cross-linked molecular structure after curing, which further improves the high temperature resistance of the material, so that it still maintains good mechanical properties and stability at high temperatures.

[0007] Preferably, the thermal decomposition temperature of the carbon fiber is at least 450°C, and the diameter of the carbon fiber is 5 to 10 microns and the length is 5 to 50 mm; the carbon fiber is surface treated by a combination of chemical and physical methods, wherein the chemical method is to use a coupling agent, the coupling agent is a silane coupling agent, a titanate coupling agent or a zirconate coupling agent, the concentration of the coupling agent is 0.5% to 2%, and the treatment time is 10 to 30 minutes; the physical method is to use plasma treatment, the treatment power is 10 to 100 watts, the treatment time is 5 to 15 minutes, and the surface treated carbon fiber has an interfacial bonding performance that is improved by at least 30%, thereby improving the overall mechanical properties of the composite material. Here, by chemically and physically treating the carbon fiber, in particular, using a coupling agent and plasma treatment, the interfacial bonding performance of the carbon fiber and the resin is improved. The interfacial bonding force of the treated carbon fiber is improved by at least 30%, thereby enhancing the overall mechanical properties of the composite material, especially maintaining high strength and stability at high temperatures.

[0008] Preferably, the additive is a phosphorus-containing flame retardant or a nitrogen-containing flame retardant, and the amount of the flame retardant added is 1% to 5% of the total weight of the composite material. Here, by adding a phosphorus-containing or nitrogen-containing flame retardant to the composite material, the material has excellent flame retardant properties, especially can effectively reduce the heat release rate in a high temperature environment, improve its fire safety, suitable for use in a high fire risk environment, and further expand the application range of the material.

[0009] Preferably, the phosphorus-containing flame retardant is a phosphate compound with a phosphorus content of 5% to 20%, and the nitrogen-containing flame retardant is melamine cyanurate with a nitrogen content of 10% to 30%. Here, by introducing the phosphorus-containing flame retardant of the phosphate ester and the nitrogen-containing flame retardant of the melamine cyanurate, the material has higher flame retardancy and durability at high temperatures, and the reasonable ratio of the flame retardant can release non-combustible gas at high temperatures, further improving the flame retardant effect of the material.

[0010] A method for using a high heat-resistant carbon fiber reinforced resin-based composite material comprises the following steps:

[0011] S1: Surface treatment step: performing surface treatment on the carbon fiber to improve the interfacial bonding performance between the carbon fiber and the thermosetting resin;

[0012] S2: Mixing step: mixing the surface-treated carbon fiber with a high heat-resistant thermosetting resin and an additive to form a prepreg, wherein the prepreg has good fluidity and adhesion at a specific temperature and pressure;

[0013] S3: Compression molding step: The prepreg is placed in a mold for molding. The molding process is controlled by appropriate temperature and pressure so that the composite material can be initially cured and formed into the desired shape;

[0014] S4: High temperature curing step: The initially formed composite material is subsequently subjected to high temperature curing treatment to further enhance the high temperature resistance and mechanical properties of the composite material.

[0015] Preferably, the surface treatment of the carbon fiber includes immersing the carbon fiber in a coupling agent solution with a pH value of 3 to 5, the coupling agent is a silane coupling agent, a titanate coupling agent or a zirconate coupling agent, the treatment time is 10 to 30 minutes, the treatment temperature is room temperature to 80°C, followed by a plasma treatment with a power of 10 to 100 watts, a treatment time of 5 to 15 minutes, and hot air drying at 60°C to 100°C for 30 to 60 minutes. Here, by immersing the carbon fiber in a coupling agent solution with a pH value of 3 to 5 and combining it with plasma treatment, the surface properties of the carbon fiber are effectively improved and its bonding performance with the resin is enhanced. At the same time, hot air drying is used to ensure that there is no residual solvent or moisture on the surface of the carbon fiber, thereby ensuring the stability of material performance in subsequent processes.

[0016] Preferably, the mixing process of the prepreg is carried out in a vacuum stirring device with a vacuum degree of 0.01 to 0.1 MPa, the mixing time is 15 to 60 minutes, the resin viscosity is controlled between 50 and 500 mPa·s by a temperature control device, and after the mixing is completed, the prepreg is cooled to 10°C to 20°C by a cooling device and stored for not less than 24 hours. Here, the mixing of the prepreg in the vacuum stirring device ensures the uniform distribution of the resin and the carbon fiber, avoids the generation of bubbles, and ensures the high density and excellent mechanical properties of the material by precisely controlling the viscosity and temperature of the resin, greatly improving the overall quality of the finished product.

[0017] Preferably, the mold forming step includes coating the inner surface of the mold with a fluoride-based or silicon-based release agent with a thickness of 0.1 to 0.5 mm, the mold temperature is controlled at 180°C to 250°C by a heating device, and a hydraulic press is used to apply a pressure of 3 to 8MPa during the molding process, and the molding time is 1 to 3 hours. Here, by coating the mold inner surface with a release agent with a thickness of 0.1 to 0.5 mm and molding at a temperature of 180°C to 250°C, it is ensured that the composite material can be smoothly demolded during the molding process, and the temperature and pressure control in the compression molding ensure the high density and surface smoothness of the composite material.

[0018] Preferably, the subsequent high-temperature curing step uses a multi-stage temperature-controlled curing furnace with a temperature control range of 350°C to 450°C, with a curing time of 2 to 8 hours, and gradually increases the temperature through a temperature control device, increasing the temperature by 30°C to 50°C every 10 minutes. After the curing is completed, a cooling device is used to cool the composite material to room temperature, and the cooling time is 1 to 3 hours. Here, a multi-stage temperature-controlled curing furnace is used for high-temperature curing to ensure that the composite material is uniformly cured at a high temperature of 350°C to 450°C, avoiding the thermal stress problem caused by uneven temperature inside the material, and further enhancing the dimensional stability and high temperature resistance of the composite material, making it suitable for long-term use in high temperature and harsh environments.

[0019] Compared with the prior art, the advantages and positive effects of the present invention are:

[0020] 1. In the present invention, the interfacial bonding performance between the carbon fiber and the highly heat-resistant thermosetting resin is effectively improved by performing a surface treatment combining chemical and physical treatment on the carbon fiber. The activity of the carbon fiber surface is enhanced by using a coupling agent chemical treatment and a plasma physical treatment, so that it can be more firmly bonded to the resin. This improvement significantly improves the mechanical strength of the composite material in a high temperature environment, reduces the delamination and interface detachment problems that may occur in long-term high temperature exposure, and thus ensures the structural stability of the material.

[0021] 2. In the present invention, the mixing process of the prepreg is precisely controlled, especially stirring in a vacuum environment, and the viscosity of the resin is adjusted by a temperature control device to ensure that the carbon fiber can be uniformly impregnated. This mixing process effectively improves the internal structure of the composite material, making it have high density and uniform distribution characteristics, and enhances the dimensional stability and creep resistance of the material at high temperatures. Through reasonable process control, the problems of insufficient resin impregnation or internal stress of the material that may occur in traditional processes are avoided.

[0022] 3. In the present invention, by precisely controlling the molding temperature, pressure and curing time during the molding and high-temperature curing process, the composite material can be stably molded, and its high-temperature resistance is further improved in the subsequent high-temperature curing stage. The use of a multi-stage temperature-controlled curing furnace ensures that the internal temperature of the composite material rises evenly, avoiding the thermal stress generated inside the material in the traditional curing process. The addition of phosphorus- or nitrogen-containing flame retardants further improves the flame retardancy of the composite material, enhances its safety performance in high-temperature and high-fire risk situations, and expands its applicability in high-temperature application fields such as aerospace and automobiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention provides a high heat-resistant carbon fiber reinforced resin-based composite material and an overall process schematic diagram of a preparation method thereof. DETAILED DESCRIPTION

[0024] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0025] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0026] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

[0027] Embodiment 1

[0028] The present invention provides a technical solution: a high heat-resistant carbon fiber reinforced resin-based composite material, 30% of carbon fiber with a diameter of 5 microns and a length of 10 mm is selected as a reinforcing material, polyimide resin is used as a matrix resin, the weight ratio is 65%, and 5% of a phosphorus-containing flame retardant is added, and a phosphate compound is used with a phosphorus content of 10%. The carbon fiber is first treated with a silane coupling agent for 20 minutes at room temperature, and then a 50-watt plasma treatment is performed for 10 minutes. After the surface treatment is completed, the carbon fiber is dried at 80°C for 30 minutes. Then, in a stirring device with a vacuum degree of 0.05MPa, the carbon fiber, polyimide resin and phosphorus-containing flame retardant are fully mixed, the mixing time is 45 minutes, and the resin viscosity is controlled at 200mPa·s to ensure that the carbon fiber is fully impregnated with the resin, and the mixed prepreg is transferred to a mold coated with a 0.2 mm fluoride-based release agent, the mold temperature is controlled at 200°C, a pressure of 5MPa is applied, and the molding time is 2 hours. After the compression molding is completed, the composite material is placed in a multi-stage temperature-controlled curing furnace, and the curing temperature is gradually increased from 350°C to 450°C, with a temperature increase of 50°C every 10 minutes, and the curing time is 6 hours. After the curing is completed, the material is cooled to room temperature using a cooling device, and the cooling time is 2 hours.

[0029] Embodiment 2

[0030] A highly heat-resistant carbon fiber reinforced resin-based composite material, 40% of carbon fiber, 6 microns in diameter and 20 mm in length, bismaleimide resin as the matrix, 55% by weight, and 5% nitrogen-containing flame retardant, melamine cyanurate, nitrogen content of 15%. The carbon fiber is treated with a titanate coupling agent solution with a pH value of 4, the treatment temperature is 60°C, the treatment time is 30 minutes, and then 80 watts of plasma treatment is carried out for 5 minutes. The drying step is carried out in a 70°C environment, and the drying time is 40 minutes. The treated carbon fiber, bismaleimide resin and nitrogen-containing flame retardant are mixed in a stirring device with a vacuum degree of 0.02MPa, the mixing time is 30 minutes, the resin viscosity is maintained at 300mPa·s, and the mixed prepreg is placed in a mold coated with a 0.3 mm thick fluoride-based release agent, the mold temperature is set to 220°C, the molding pressure is 6MPa, and the molding time is 1.5 hours. After the compression molding is completed, the composite material is placed in a curing furnace for high-temperature curing. The curing temperature is gradually increased from 370°C to 420°C, with a temperature increase of 30°C every 10 minutes. The curing time is 4 hours. Finally, the composite material is cooled to room temperature through a cooling device. The cooling time is 2.5 hours.

[0031] Embodiment 3

[0032] A highly heat-resistant carbon fiber reinforced resin-based composite material uses 50% carbon fiber with a diameter of 7 microns and a length of 30 mm, benzoxazine resin as a matrix, with a weight ratio of 45%, and 5% phosphorus-containing flame retardant is added, using phosphate compounds with a phosphorus content of 12%. The carbon fiber is first treated with a zirconate coupling agent solution with a pH value of 4.5 for 25 minutes and a treatment temperature of 70°C, followed by a 100-watt plasma treatment for 10 minutes. After treatment, the carbon fiber is dried at 60°C for 50 minutes. The treated carbon fiber, benzoxazine resin and phosphorus-containing flame retardant are mixed in a stirring device with a vacuum degree of 0.03MPa for 60 minutes, and the resin viscosity is controlled at 100mPa·s. The mixed prepreg is placed in a mold with a 0.4mm thick silicate-based release agent coated on the inner surface, and the mold temperature is set to 180°C, the molding pressure is 8MPa, and the molding time is 3 hours. After molding, the material is placed in a temperature-controlled curing furnace for high-temperature curing. The temperature is gradually increased from 400°C to 450°C, with a temperature increase interval of 50°C every 10 minutes, and the curing time is 8 hours. Finally, the material is slowly cooled to room temperature using a cooling device, and the cooling time is 3 hours.

[0033] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A high heat-resistant carbon fiber reinforced resin-based composite material, characterized in that: The composite material includes the following components in weight percentage: 30% to 70% carbon fiber, 25% to 65% high heat-resistant thermosetting resin, and 0.1% to 5% additives, wherein the additive is at least one of a heat-resistant agent, a toughening agent, an antioxidant, a flame retardant or a moisture-proof agent. The carbon fiber is surface-treated to improve its interfacial bonding performance with the thermosetting resin. The composite material has a thermal decomposition temperature of at least 350°C and maintains more than 90% of its mechanical strength at this temperature. The composite material is suitable for long-term exposure to a high temperature environment of 300°C to 450°C, and exhibits excellent dimensional stability, aging resistance and creep resistance under such high temperature conditions.

2. The high heat-resistant carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The high heat-resistant thermosetting resin is selected from polyimide resin, bismaleimide resin, benzoxazine resin, polyaryletherketone resin or a combination thereof, wherein the glass transition temperature of the polyimide resin is not less than 300°C, the curing temperature range of the bismaleimide resin is 180°C to 250°C, the benzoxazine resin forms a highly cross-linked network structure after curing, and the polyaryletherketone resin has excellent chemical stability and radiation resistance; the resin is subjected to at least one preliminary curing and one high-temperature secondary curing treatment to form a highly cross-linked molecular structure, thereby enhancing the high temperature resistance, creep resistance and oxidation resistance of the composite material, and is suitable for long-term use in a high temperature environment.

3. The high heat-resistant carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The thermal decomposition temperature of the carbon fiber is at least 450°C, and the diameter of the carbon fiber is 5 to 10 microns and the length is 5 to 50 millimeters. The carbon fiber is surface treated by combining chemical and physical methods, wherein the chemical method is to use a coupling agent, the coupling agent is a silane coupling agent, a titanate coupling agent or a zirconate coupling agent, the concentration of the coupling agent is 0.5% to 2%, and the treatment time is 10 to 30 minutes; the physical method is to use plasma treatment, the treatment power is 10 to 100 watts, and the treatment time is 5 to 15 minutes. The interface bonding performance of the carbon fiber after the surface treatment is improved by at least 30%, thereby improving the overall mechanical properties of the composite material.

4. The high heat-resistant carbon fiber reinforced resin-based composite material and the preparation method thereof according to claim 1, characterized in that: The additive is a phosphorus-containing flame retardant or a nitrogen-containing flame retardant, and the added amount of the flame retardant is 1% to 5% of the total weight of the composite material.

5. The high heat-resistant carbon fiber reinforced resin-based composite material and the preparation method thereof according to claim 4, characterized in that: The phosphorus-containing flame retardant is a phosphate compound with a phosphorus content of 5% to 20%, and the nitrogen-containing flame retardant is melamine cyanurate with a nitrogen content of 10% to 30%.

6. A method for using the high heat-resistant carbon fiber reinforced resin-based composite material according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: Surface treatment step: performing surface treatment on the carbon fiber to improve the interfacial bonding performance between the carbon fiber and the thermosetting resin; S2: Mixing step: mixing the surface-treated carbon fiber with a high heat-resistant thermosetting resin and an additive to form a prepreg, wherein the prepreg has good fluidity and adhesion at a specific temperature and pressure; S3: Compression molding step: The prepreg is placed in a mold for molding. The molding process is controlled by appropriate temperature and pressure so that the composite material can be initially cured and formed into the desired shape; S4: High temperature curing step: The initially formed composite material is subsequently subjected to high temperature curing treatment to further enhance the high temperature resistance and mechanical properties of the composite material.

7. The high heat-resistant carbon fiber reinforced resin-based composite material and the preparation method thereof according to claim 6, characterized in that: The surface treatment of the carbon fiber comprises immersing the carbon fiber in a coupling agent solution with a pH value of 3 to 5, wherein the coupling agent is a silane coupling agent, a titanate coupling agent or a zirconate coupling agent, the treatment time is 10 to 30 minutes, the treatment temperature is room temperature to 80°C, followed by plasma treatment with a power of 10 to 100 watts, the treatment time is 5 to 15 minutes, and hot air drying is performed at 60°C to 100°C for 30 to 60 minutes.

8. The high heat-resistant carbon fiber reinforced resin-based composite material and the preparation method thereof according to claim 6, characterized in that: The mixing process of the prepreg is carried out in a vacuum stirring device with a vacuum degree of 0.01 to 0.1 MPa, the mixing time is 15 to 60 minutes, the resin viscosity is controlled between 50 and 500 mPa·s by a temperature control device, and after the mixing is completed, the prepreg is cooled to 10° C. to 20° C. by a cooling device and stored for not less than 24 hours.

9. The high heat-resistant carbon fiber reinforced resin-based composite material and the preparation method thereof according to claim 6, characterized in that: The mold forming step includes coating the inner surface of the mold with a fluoride-based or silicon-based release agent with a thickness of 0.1 to 0.5 mm, controlling the mold temperature at 180° C. to 250° C. by a heating device, applying a pressure of 3 to 8 MPa using a hydraulic press during the molding process, and the molding time is 1 to 3 hours.

10. The high heat-resistant carbon fiber reinforced resin-based composite material and the preparation method thereof according to claim 6, characterized in that: The subsequent high-temperature curing step uses a multi-stage temperature-controlled curing furnace with a temperature controlled at 350°C to 450°C. The curing time is 2 to 8 hours, and the temperature is gradually increased by a temperature control device, increasing by 30°C to 50°C every 10 minutes. After the curing is completed, a cooling device is used to cool the composite material to room temperature. The cooling time is 1 to 3 hours.

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