A high wear-resistant carbon fiber prepreg and preparation method thereof

Abstract

The present invention provides a highly wear-resistant carbon fiber prepreg and a preparation method thereof, belonging to the technical field of carbon fiber composite materials. The present invention specifically uses carbon fiber, salicylic acid modified epoxy resin, polystyrene butadiene copolymer, locust bean gum, 4-acetylaminosalicylic acid, modified silicon carbide powder, a curing agent, and an accelerator as raw materials to prepare the carbon fiber prepreg. The components have good compatibility. Through the coordinated effect of the components, the defects of the carbon fiber prepreg in the prior art are compensated. The wear resistance, high temperature resistance, mechanical properties and stability of the material are improved, making it more widely used in civilian, aerospace, and military applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon fiber composite materials, and in particular relates to a high-wear-resistant carbon fiber prepreg and a preparation method thereof. Background Art

[0002] Carbon fiber is a new type of fiber material with a carbon content of more than 95%. It is lighter than metallic aluminum but stronger than steel. It has excellent tensile strength, high temperature resistance, flexibility, resistance to corrosion by inorganic acids and alkali reagents, and aging resistance. It is one of the most commonly used reinforcing materials and is widely used in fishing gear, sports equipment, sporting goods, aerospace, military products, etc.

[0003] The key technology of carbon fiber composite material is the preparation process of fiber, resin and prepreg, and prepreg is important intermediate product in composite material production, and its quality directly affects the overall performance of composite material. Carbon fiber prepreg is generally made of materials such as carbon fiber yarn, resin, release paper, through the process processing such as coating, hot pressing, cooling, laminating, winding. The selection of matrix resin determines the environmental resistance, toughness, processing performance and some mechanical properties (such as lateral performance, compression performance etc.) of composite material to a great extent. Therefore, the selection of matrix resin is particularly critical. Epoxy resin is the most widely used matrix resin at present, but the temperature resistance and light resistance of epoxy resin are poor, and carbon fiber is mainly composed of graphite-based carbon, has natural chemical inertness, surface energy is higher, and the bonding property with epoxy resin is poor, and interfacial bonding force is weak, causes compression, bending and interlaminar shear strength of composite material to be all lower, affects the further improving of material performance, limits its scope of application.

[0004] Patent CN107057283A discloses a method for improving the interfacial bonding strength of carbon fiber and epoxy resin. This method involves adding graphene oxide, carbon nanotubes, and isocyanate to the epoxy resin to enhance the interfacial bonding strength and wetting effect between the epoxy resin and carbon fiber, thereby improving the flexural strength and interlaminar shear strength of the composite material. Patent CN106046682A discloses a method for improving the performance of epoxy resin-fiber composite materials. This method involves adding halloysite / carbon nanocomposite to the epoxy resin to improve the interfacial bonding strength between the epoxy resin and the fiber, thereby enhancing overall performance. Patent application CN102295740A provides a polyamide-imide-cured epoxy resin composite method, which uses a curing agent polyamide-imide or a mixture of polyamide-imide and other curing agents to cure the epoxy resin. The different ratios of various components in the raw materials are calculated based on the chemical equivalents of the epoxy functional groups in the epoxy resin and the amide functional groups in the polyamide-imide, so that the polyamide-imide has a good curing effect. However, it will shorten the gel time of the epoxy resin and have poor interfacial compatibility with carbon fiber, affecting the mechanical properties of the carbon fiber. Although great progress has been made in the research of carbon fiber prepregs, there are still deficiencies in the wear resistance and mechanical strength of carbon fiber composites.

[0005] Therefore, it is urgent to develop a carbon fiber prepreg with excellent wear resistance and mechanical strength. Summary of the Invention

[0006] Based on the problems existing in the above-mentioned carbon fiber prepreg, the present invention provides a carbon fiber prepreg. By adding salicylic acid phenol-modified epoxy resin into the prepreg, the epoxy resin modified by salicylic acid phenol makes up for the defects of poor toughness and poor compatibility between the epoxy resin and carbon fiber. The epoxy resin has good compatibility with the carbon fiber, and the mechanical properties and high temperature resistance of the carbon fiber prepreg are improved. Moreover, through the coordinated effect of the various components, the obtained carbon fiber prepreg also has excellent wear resistance. At the same time, the prepreg has good stability at room temperature and can be stored for a long time, and has broad application prospects.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0008] [1] A carbon fiber prepreg comprising the following components, in parts by weight:

[0009] 30-40 parts by weight of carbon fiber, 35-50 parts by weight of salicylic acid modified epoxy resin, 12-20 parts by weight of polystyrene butadiene copolymer, 2-3 parts by weight of locust bean gum, 4-7 parts by weight of 4-acetylaminosalicylic acid, 3-5 parts by weight of modified silicon carbide powder, 1-3 parts by weight of curing agent, and 2-5 parts by weight of accelerator.

[0010] This application prepares carbon fiber prepreg by using carbon fiber, salicylic acid modified epoxy resin, polystyrene butadiene copolymer, locust bean gum, 4-acetylaminosalicylic acid, modified silicon carbide powder, curing agent, and accelerator as raw materials. The components have good compatibility. Through the coordinated effect of the components, the defects of carbon fiber prepreg in the existing technology are compensated. The wear resistance, high temperature resistance, mechanical properties and stability of the material are improved, making it more widely used in civil, aerospace, and military industries.

[0011] In some specific embodiments, the butadiene content of the styrene-butadiene copolymer is 10-50% by mole, preferably 25-40% by mole; the number average molecular weight is 1-4×10 -5 , preferably 1.5~2×10 -5 , with a molecular weight distribution of 1 to 1.3. In this application, the copolymer is formed by polymerizing butadiene and styrene in a specific ratio, and has good toughness and rigidity. It can improve the mechanical properties of the prepreg and enhance the impact resistance. To ensure the processability and overall performance of the prepreg, the amount of polystyrene butadiene copolymer added is lower than the amount of modified epoxy resin.

[0012] In some specific embodiments, the curing agent is any one of an aromatic amine curing agent, a polyether amine curing agent, and a polycarboxylic acid anhydride curing agent, or a mixture of several of them.

[0013] In some embodiments, the accelerator is a urea accelerator.

[0014] In some specific embodiments, the modified epoxy resin is prepared by reacting bisphenol A, salaminophenol, and epichlorohydrin under alkaline conditions.

[0015] In some specific embodiments, the molar ratio of bisphenol A, salicylic acid phenol, and epichlorohydrin is 2-4:0.2-0.4:10.

[0016] Furthermore, the modified epoxy resin is prepared specifically by the following method:

[0017] Bisphenol A, salaminophenol, and epichlorohydrin are mixed, an auxiliary agent is added, and the mixture is stirred under N2 protection to completely dissolve; NaOH is then added, with the molar ratio of NaOH to epichlorohydrin being 0.2-0.4:1, and the mixture is reacted at 30-50°C for 2-6 hours; the mixture is filtered; the filtrate is allowed to stand for separation, the water layer is removed, and the mixture is distilled under reduced pressure to obtain the product.

[0018] Furthermore, the auxiliary agent is one or a mixture of tetrabutylammonium bromide, tetrabutylammonium hydrogen sulfate, tetrabutylammonium chloride, tetraethylammonium bromide, dioctadecyldimethylammonium chloride, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, methyltrioctylammonium chloride, and hexadecyltrimethylammonium bromide, and the amount of the added auxiliary agent is 0.4-1% of the mass of epichlorohydrin.

[0019] Furthermore, the temperature range during the reduced pressure distillation process is 80-95°C.

[0020] The present application adopts the above technical solution to prepare epoxy resin by reacting bisphenol A, salaminophenol and epichlorohydrin. During the preparation process, salaminophenol is added. Salaminophenol contains bisphenol hydroxyl groups, which can react with epichlorohydrin to be blocked in the epoxy resin chain segment. Controlling the amount of salaminophenol added will not affect the properties of bisphenol A epoxy resin, which has high strength and strong adhesion, and makes up for the defects of high internal stress, poor toughness, brittleness and poor impact resistance caused by high cross-linking density of epoxy resin after curing. This may be due to the introduction of a specific molar amount of salaminophenol, which increases the distance between molecules in the obtained epoxy resin molecular chain and the intermolecular force. The addition of isocyanate can improve the high temperature resistance of epoxy resin, thereby improving the high temperature resistance of carbon fiber prepreg, which may be related to the amide group in the isocyanate molecule. It is also found that the introduction of isocyanate into epoxy resin can improve the dispersibility of epoxy resin, increase the bonding between epoxy resin and carbon fiber, improve the compatibility between epoxy resin and carbon fiber, and improve the bending strength and interlaminar shear strength.

[0021] In some specific embodiments, the weight ratio of locust bean gum to 4-acetylaminosalicylic acid is 1:2-2.6.

[0022] In this application, locust bean gum and 4-acetylaminosalicylic acid are added to a carbon fiber prepreg. The interaction between the two compounds enhances the material's stability, allowing it to retain good performance even after prolonged storage at room temperature. This is likely due to the fact that the addition of locust bean gum and 4-acetylaminosalicylic acid prevents further reaction of the epoxy resin, thereby improving room-temperature stability. Furthermore, the applicant has discovered that when locust bean gum and 4-acetylaminosalicylic acid are added in certain amounts, particularly at a weight ratio of 1:2 to 2.6, the material's wear resistance can be enhanced.

[0023] In some specific embodiments, the modified silicon carbide powder is prepared by polyether-modified trisiloxane-modified silicon carbide powder. Specifically, polyether-modified trisiloxane is added to ethanol to prepare a modified solution with a mass fraction of 10 to 20%. The silicon carbide powder is ultrasonically dispersed in the modified solution, and the reaction is stirred at 80 to 100° C. for 30 to 80 minutes to obtain the modified silicon carbide powder.

[0024] In the present application, modified silicon carbide powder is added to the prepreg as a filler to improve the high-temperature resistance of the carbon fiber composite material. However, the dispersibility of nano-silicon carbide is poor. It is easy to agglomerate when added directly to the prepreg and will not be evenly dispersed in the prepreg, which will cause stress concentration and thus reduce the mechanical properties of the composite material. In the present application, silicon carbide is modified with polyether-modified trisiloxane and then added to the prepreg. The polyether-modified trisiloxane reacts with the groups on the surface of silicon carbide to reduce the surface energy, increase the dispersibility of silicon carbide, improve the compatibility of silicon carbide with other materials in the composite material, reduce stress concentration, and interact with other components through chemical bonding to achieve reinforcement of the epoxy resin, improve the wear resistance of the material, and also enhance the mechanical strength.

[0025] [2] The method for preparing the carbon fiber prepreg described in [1] above comprises:

[0026] The salicylic acid modified epoxy resin, polystyrene butadiene copolymer and curing agent are mixed, and stirred at 70-80° C. to obtain a mixed solution; then modified silicon carbide powder and accelerator are added, and stirring is continued at 70-80° C. to obtain a mixed solution; locust bean gum and 4-acetylaminosalicylic acid are added, and stirring is continued at 50-60° C. to obtain a mixed solution; the temperature is raised to 100-120° C., carbon fiber is added, and the carbon fiber is fully impregnated and then taken out and cooled to obtain the obtained solution.

[0027] [3] Application of hydroxyethyl amine modified epoxy resin in improving the toughness and high temperature resistance of carbon fiber prepreg.

[0028] [4] The role of locust bean gum and 4-acetylaminosalicylic acid in improving the wear resistance and stability of carbon fiber prepreg.

[0029] Beneficial effects:

[0030] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0031] 1) The present application prepares a carbon fiber prepreg using carbon fiber, salicylic acid modified epoxy resin, polystyrene butadiene copolymer, locust bean gum, 4-acetylaminosalicylic acid, modified silicon carbide powder, curing agent, and accelerator as raw materials. The components have good compatibility. Through the coordinated effect of the components, the defects of the existing carbon fiber prepreg are compensated, and the wear resistance, high temperature resistance, mechanical properties and stability of the final product carbon fiber composite material are improved, making it more widely used in civil, aerospace, and military industries;

[0032] 2) The modified epoxy resin prepared by introducing a specific amount of salicylic acid phenol into the epoxy resin compensates for the poor toughness of the epoxy resin, improves the toughness of the epoxy resin, and also increases the high-temperature resistance of the epoxy resin, which may be related to the amide group in the salicylic acid phenol molecule. The introduction of salicylic acid phenol into the epoxy resin can also increase the bonding between the epoxy resin and the carbon fiber, increase the compatibility of the epoxy resin and the carbon fiber, and improve the bending strength and interlaminar shear strength.

[0033] 3) The addition of locust bean gum and 4-acetylaminosalicylic acid in the present application increases the stability of the prepreg and prolongs the storage time by utilizing the interaction between locust bean gum and 4-acetylaminosalicylic acid. When locust bean gum and 4-acetylaminosalicylic acid are added in a certain ratio, especially when the weight ratio is 1:2 to 2.6, the wear resistance of the material is also improved.

[0034] 4) Silicon carbide is modified with polyether-modified trisiloxane and then added to the prepreg. The polyether-modified trisiloxane reacts with the groups on the surface of silicon carbide, reducing the surface energy, increasing the dispersibility of silicon carbide, improving the compatibility of silicon carbide with other materials in the composite material, reducing stress concentration, achieving reinforcement of the epoxy resin, and improving the wear resistance and mechanical strength of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 FTIR graphs of the modified epoxy resins of the present invention; (a) represents the salicylic acid phenol modified epoxy resin prepared in Example 3, and (b) represents the modified epoxy resin prepared in Comparative Example 3;

[0036] Figure 2 1 is a schematic diagram of the test results of the high temperature resistance (tensile strength retention rate) of carbon fiber prepreg;

[0037] Figure 3 It is a schematic diagram of the wear resistance test results of carbon fiber prepreg. DETAILED DESCRIPTION

[0038] To facilitate understanding of the present invention, the present invention will be described more fully below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0039] According to the present application, a modified epoxy resin is first provided, which is prepared by the following method:

[0040] Bisphenol A, salicylic acid phenol, and epichlorohydrin are mixed in a molar ratio of 2-4:0.2-0.4:10, an auxiliary agent of 0.4-1% by weight of epichlorohydrin is added, and the mixture is stirred under nitrogen protection to completely dissolve; NaOH is then added thereto in a molar ratio of NaOH to epichlorohydrin of 0.2-0.4:1, and the mixture is reacted at 30-50° C. for 2-6 hours; the mixture is filtered; the filtrate is allowed to stand for separation, the water layer is removed, and the mixture is distilled under reduced pressure to obtain the product. The modified epoxy resin is prepared by using the above method. Adding a certain amount of salicylic acid phenol to the epoxy resin does not affect the characteristics of bisphenol A epoxy resin, and has high strength and strong adhesion. It also makes up for the defects of the epoxy resin. The distance between molecules in the resulting epoxy resin molecular chain is increased, and the intermolecular force is reduced, which makes the movement ability of the chain segments easier and reduces the mutual entanglement between polymer molecules. It has a good toughening effect on the epoxy resin, reduces brittleness, and makes the cured epoxy resin have both good toughness and strength. The addition of salicylic acid phenol also has the effect of increasing the weather resistance of the epoxy resin and improving the high temperature resistance, which may be related to the amide group in the salicylic acid phenol molecule. It is also found that the introduction of salicylic acid phenol into the epoxy resin can improve the dispersibility of the epoxy resin, increase the compatibility of the epoxy resin with carbon fiber, and improve the bending strength and interlaminar shear strength.

[0041] According to the present application, a modified silicon carbide powder is also provided, which is prepared by the following method:

[0042] Polyether-modified trisiloxane is added to ethanol to prepare a modified solution with a mass fraction of 10-20%, silicon carbide powder is ultrasonically dispersed in the modified solution, and the mixture is stirred at 80-100°C for 30-80 minutes to obtain modified silicon carbide powder. Modified silicon carbide powder is added to prepreg as a filler to improve the high-temperature resistance of the final carbon fiber composite material. However, nano-silicon carbide has poor dispersibility and is prone to agglomeration when added directly to the prepreg. It is not evenly dispersed in the prepreg, which causes stress concentration and thus reduces the mechanical properties of the composite material. In this application, silicon carbide is modified with polyether-modified trisiloxane and then added to the prepreg. The polyether-modified trisiloxane reacts with groups on the surface of silicon carbide, reducing surface energy and increasing the dispersibility of silicon carbide. This improves the compatibility of silicon carbide with other materials in the composite material, reduces stress concentration, and forms blocks through chemical bonding interactions with other components, thereby reinforcing the epoxy resin, improving the material's wear resistance, and enhancing mechanical strength.

[0043] According to the present application, a carbon fiber prepreg is also provided, comprising the following components:

[0044] 30-40 parts by weight of carbon fiber, 35-50 parts by weight of salicylic acid modified epoxy resin, 12-20 parts by weight of polystyrene butadiene copolymer, 2-3 parts by weight of locust bean gum, 4-acetylaminosalicylic acid 4-7 parts by weight, 3-5 parts by weight of modified silicon carbide powder, 1-3 parts by weight of curing agent, and 2-5 parts by weight of accelerator. The weight ratio of locust bean gum and 4-acetylaminosalicylic acid is 1:2-2.6. In the present application, by adding locust bean gum and 4-acetylaminosalicylic acid to the carbon fiber prepreg, the interaction between locust bean gum and 4-acetylaminosalicylic acid is utilized to increase the stability of the material, so that the material can still retain good performance after being stored for a long time at room temperature. This may be because the addition of locust bean gum and 4-acetylaminosalicylic acid introduces a certain amount of electrophilic groups, which can prevent further reaction of the epoxy resin, thereby improving the room temperature stability. In addition, the applicant has found that when locust bean gum and 4-acetylaminosalicylic acid are added in a certain amount, especially when the weight ratio is 1:2 to 2.6, the wear resistance of the material can be improved.

[0045] According to the present application, a method for preparing a carbon fiber prepreg is also provided, comprising:

[0046] The modified epoxy resin, polystyrene butadiene copolymer, and curing agent are mixed and stirred at 70-80°C to obtain a mixed solution; then modified silicon carbide powder and accelerator are added and stirred at 70-80°C to obtain a mixed solution; locust bean gum and 4-acetylaminosalicylic acid are added and stirred at 50-60°C to obtain a uniform mixture; the mixture is heated to 100-120°C, and carbon fiber is added and fully impregnated with the carbon fiber before being removed and cooled to obtain a carbon fiber prepreg. The carbon fiber prepreg is prepared by using carbon fiber, salicylic acid modified epoxy resin, polystyrene butadiene copolymer, locust bean gum, 4-acetylaminosalicylic acid, modified silicon carbide powder, curing agent, and accelerator as raw materials. The components cooperate with each other to make up for the defects of the existing carbon fiber prepreg, improve the wear resistance, high temperature resistance, mechanical properties, and stability of the final carbon fiber composite material, and make it more widely used in civil, aerospace, and military industries.

[0047] The present invention will be explained in detail below with reference to the embodiments.

[0048] Example 1:

[0049] A salicylic acid phenol modified epoxy resin is prepared by the following method:

[0050] Mix bisphenol A (0.3 mol, 68.4 g), salicylic acid phenol (0.01 mol, 2.29 g), and epichlorohydrin (1 mol, 92 g), add 0.5 g of methyltrioctylammonium chloride, and stir under N2 protection to completely dissolve it; then add 12 g of NaOH and react at 40°C for 4 h; filter; let the filtrate stand to separate the layers, remove the water layer, and distill under reduced pressure to obtain the product.

[0051] Example 2:

[0052] Another salicylic acid phenol modified epoxy resin was prepared by the following method:

[0053] Mix bisphenol A (0.3 mol, 68.4 g), salicylic acid phenol (0.02 mol, 4.58 g), and epichlorohydrin (1 mol, 92 g), add 0.5 g of methyltrioctylammonium chloride, and stir under N2 protection to completely dissolve it; then add 12 g of NaOH and react at 40°C for 4 h; filter; let the filtrate stand to separate the layers, remove the water layer, and distill under reduced pressure to obtain the product.

[0054] Example 3:

[0055] Another salicylic acid phenol modified epoxy resin was prepared by the following method:

[0056] Mix bisphenol A (0.3 mol, 68.4 g), salicylic acid phenol (0.03 mol, 6.87 g), and epichlorohydrin (1 mol, 92 g), add 0.5 g of methyltrioctylammonium chloride, and stir under N2 protection to completely dissolve it; then add 12 g of NaOH and react at 40°C for 4 h; filter; let the filtrate stand to separate the layers, remove the water layer, and distill under reduced pressure to obtain the product.

[0057] Example 4:

[0058] Another salicylic acid phenol modified epoxy resin was prepared by the following method:

[0059] Mix bisphenol A (0.3 mol, 68.4 g), isothiocyanate (0.04 mol, 9.16 g), and epichlorohydrin (1 mol, 92 g), add 0.5 g of methyltrioctylammonium chloride, and stir under N2 protection to completely dissolve it; then add 12 g of NaOH and react at 40°C for 4 h; filter; let the filtrate stand to separate the layers, remove the water layer, and distill under reduced pressure to obtain the product.

[0060] Example 5:

[0061] Another salicylic acid phenol modified epoxy resin was prepared by the following method:

[0062] Mix bisphenol A (0.3 mol, 68.4 g), salicylic acid phenol (0.05 mol, 11.45 g), and epichlorohydrin (1 mol, 92 g), add 0.5 g of methyltrioctylammonium chloride, and stir under N2 protection to completely dissolve it; then add 12 g of NaOH and react at 40°C for 4 h; filter; let the filtrate stand to separate the layers, remove the water layer, and distill under reduced pressure to obtain the product.

[0063] Comparative Example 1:

[0064] Another modified epoxy resin was prepared by the following method:

[0065] Mix bisphenol A (0.3 mol, 68.4 g) and epichlorohydrin (1 mol, 92 g), add 0.5 g of methyltrioctylammonium chloride, and stir under N2 protection to completely dissolve it; then add 12 g of NaOH and react at 40°C for 4 h; filter; let the filtrate stand to separate the layers, remove the water layer and distill under reduced pressure to obtain the product.

[0066] Test Example 1:

[0067] Structural characterization of modified epoxy resin:

[0068] H 1 -NMR characterization: The modified epoxy resin prepared in Example 3 and the modified epoxy resin prepared in Comparative Example 1 were used as samples, respectively, and the modified epoxy resin was prepared in Example 3 and the modified epoxy resin was prepared in Comparative Example 1. UNITY The test was carried out using an INOVA-300 superconducting high-resolution Fourier transform nuclear magnetic resonance spectrometer, with CDCl3 as the solvent.

[0069] Infrared characterization: The modified epoxy resin prepared in Example 3 and Comparative Example 1 was used as raw material and tested using a Spectrum One Fourier transform infrared spectrometer from PE Company of the United States. The scanning number was 16 times and the frequency range was 4000-500 cm -1 , the results are as follows Figure 1 shown.

[0070] The modified epoxy resin prepared in Example 3 was tested by nuclear magnetic hydrogen spectrum. The results showed that both modified epoxy resins had a single peak at 1.7 for the methyl group in bisphenol A, 6.8 and 7.1 for the chemical shift of hydrogen on the benzene ring in bisphenol A, the peaks at 2.7 and 2.9 for the chemical shift of two hydrogens in the methylene group on the epoxy group, the peak at 3.2 for the chemical shift of hydrogen in the methylene group on the epoxy group, and 4.0 and 4.2 for the chemical shift of two hydrogens in the methylene group adjacent to the epoxy group. Compared with Example 3 and Comparative Example 1, in Example 3, chemical shifts attributable to hydrogen on the benzene ring in salicylic acid phenol appeared at 7.1 to 7.6, and a chemical shift of hydrogen in the amide group in salicylic acid phenol appeared at 9.8. It can be seen that the modified epoxy resin contains salicylic acid phenol segments.

[0071] Figure 1 The FTIR graphs of the modified epoxy resins obtained in Example 3 and Comparative Example 1 are shown in curves (a) and (b). The two curves have a wavelength of 1100 cm -1 The absorption peak of ether bond (COC) appears near 910 cm -1 Nearby is the absorption peak of the end epoxy group; compared with curve (b), curve (a) is at 1650cm -1 、1540cm -1 There are two obvious absorption peaks nearby, namely the characteristic absorption peaks of amide I band and amide II band, 1290 cm -1 The absorption peak nearby is the characteristic peak of the amide III band, which shows that hydroxychloroquine successfully reacts with epichlorohydrin, that is, the modified epoxy resin contains hydroxychloroquine chain segments.

[0072] Example 6:

[0073] A carbon fiber prepreg, comprising the following components in parts by weight:

[0074] 32 parts by weight of carbon fiber, 45 parts by weight of the epoxy resin modified by salicylic acid obtained in Example 1, 15 parts by weight of polystyrene butadiene copolymer (butadiene accounts for 32% of the molar weight of the copolymer, and the number average molecular weight is 2×10 -5 , molecular weight distribution 1.2), 2 parts by weight of locust bean gum, 5 parts by weight of 4-acetylaminosalicylic acid, 5 parts by weight of modified silicon carbide powder, 2 parts by weight of pyromellitic dianhydride, and 4 parts by weight of UR500 accelerator.

[0075] The modified silicon carbide powder is prepared by the following method:

[0076] 1.6 parts by weight of polyether-modified trisiloxane was added to ethanol to prepare a modified solution with a mass fraction of 16%, 20 parts by weight of silicon carbide powder was ultrasonically dispersed in the modified solution, and the mixture was stirred and reacted at 90° C. for 60 minutes to obtain the product.

[0077] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, comprising the following steps:

[0078] Mix salicylic acid modified epoxy resin, polystyrene butadiene copolymer, and pyromellitic dianhydride, and stir thoroughly at 75°C to obtain a mixed solution; then add modified silicon carbide powder and UR500 accelerator, and continue to stir thoroughly at 75°C to obtain a mixed solution; add locust bean gum and 4-acetylaminosalicylic acid, stir thoroughly at 60°C, heat to 110°C, add carbon fiber, fully soak the carbon fiber, and then take out and cool to obtain the obtained solution.

[0079] Example 7:

[0080] Another carbon fiber prepreg has the same components as those in Example 6, except that the salicylic acid phenol-modified epoxy resin obtained in Example 2 is used instead of the salicylic acid phenol-modified epoxy resin obtained in Example 1.

[0081] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, and the steps are the same as those in Example 6.

[0082] Example 8:

[0083] Another carbon fiber prepreg has the same components as those in Example 6, except that the salicylic acid phenol-modified epoxy resin obtained in Example 3 is used instead of the salicylic acid phenol-modified epoxy resin obtained in Example 1.

[0084] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, and the steps are the same as those in Example 6.

[0085] Example 9:

[0086] Another carbon fiber prepreg has the same components as those in Example 6, except that the salicylic acid phenol-modified epoxy resin obtained in Example 4 is used instead of the salicylic acid phenol-modified epoxy resin obtained in Example 1.

[0087] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, and the steps are the same as those in Example 6.

[0088] Example 10:

[0089] Another carbon fiber prepreg has the same components as those in Example 6, except that the salicylic acid phenol-modified epoxy resin obtained in Example 5 is used instead of the salicylic acid phenol-modified epoxy resin obtained in Example 1.

[0090] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, and the steps are the same as those in Example 6.

[0091] Example 11:

[0092] Another carbon fiber prepreg has the same components as those in Example 6, except that the modified epoxy resin obtained in Comparative Example 1 is used instead of the salicylic acid phenol modified epoxy resin obtained in Example 1.

[0093] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, and the steps are the same as those in Example 6.

[0094] Example 12:

[0095] Another carbon fiber prepreg has substantially the same components as those in Example 6, except that the amount of locust bean gum and 4-acetylaminosalicylic acid are both 2 parts by weight.

[0096] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, and the steps are the same as those in Example 6.

[0097] Example 13:

[0098] Another carbon fiber prepreg has the same components as those in Example 6, except that locust bean gum and 4-acetylaminosalicylic acid are 2 parts by weight and 4 parts by weight, respectively.

[0099] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, and the steps are the same as those in Example 6.

[0100] Example 14:

[0101] Another carbon fiber prepreg has substantially the same components as those in Example 6, except that locust bean gum and 4-acetylaminosalicylic acid are present in amounts of 2 parts by weight and 5.2 parts by weight, respectively.

[0102] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, and the steps are the same as those in Example 6.

[0103] Example 15:

[0104] Another carbon fiber prepreg has the same components as those in Example 6, except that locust bean gum and 4-acetylaminosalicylic acid are 2 parts by weight and 8 parts by weight, respectively.

[0105] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, and the steps are the same as those in Example 6.

[0106] Comparative Example 2:

[0107] Another carbon fiber prepreg has components substantially the same as those of Example 6, except that locust bean gum is not added.

[0108] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, comprising the following steps:

[0109] Mix salicylic acid modified epoxy resin, polystyrene butadiene copolymer, and pyromellitic dianhydride, and stir thoroughly at 75°C to obtain a mixed solution; then add modified silicon carbide powder and UR500 accelerator, and continue to stir thoroughly at 75°C to obtain a mixed solution; add 4-acetylaminosalicylic acid, stir and mix thoroughly at 60°C, raise the temperature to 110°C, add carbon fiber, fully soak the carbon fiber, take out and cool to obtain the product.

[0110] Comparative Example 3:

[0111] Another carbon fiber prepreg has substantially the same components as those in Example 6, except that 4-acetylaminosalicylic acid is not added.

[0112] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, comprising the following steps:

[0113] Mix salicylic acid modified epoxy resin, polystyrene butadiene copolymer, and pyromellitic dianhydride, and stir thoroughly at 75°C to obtain a mixed solution; then add modified silicon carbide powder and UR500 accelerator, and continue to stir thoroughly at 75°C to obtain a mixed solution; add locust bean gum, stir and mix thoroughly at 60°C, raise the temperature to 110°C, add carbon fiber, fully soak the carbon fiber, and then take out and cool to obtain the obtained solution.

[0114] Comparative Example 4:

[0115] Another carbon fiber prepreg has components substantially the same as those of Example 6, except that locust bean gum and 4-acetylaminosalicylic acid are not added.

[0116] This embodiment also provides a method for preparing the above-mentioned carbon fiber prepreg, comprising the following steps:

[0117] Mix salicylic acid modified epoxy resin, polystyrene butadiene copolymer, and pyromellitic dianhydride, and stir thoroughly at 75°C to obtain a mixed solution; then add modified silicon carbide powder and UR500 accelerator, and continue stirring thoroughly at 75°C to obtain a mixed solution; heat to 110°C, add carbon fiber, fully soak the carbon fiber, and then take out and cool to obtain the obtained solution.

[0118] Test Example 2:

[0119] Mechanical properties test of carbon fiber prepreg:

[0120] The carbon fiber prepregs obtained in Examples 6 to 11 were used as samples, and the tensile strength, tensile modulus, flexural strength, and interlaminar shear strength of the samples were tested with reference to GB / T3354-2014, GB / T1449-2005, and GB / T1450.1-2005 standards, respectively. The measured results are shown in Table 1.

[0121] Table 1 Mechanical properties

[0122]

[0123]

[0124] Table 1 is the mechanical property test results of the carbon fiber prepreg prepared by the method described in the present application. It can be seen from Table 1 that the carbon fiber prepreg obtained in the present application has excellent strength and toughness, and has high tensile strength, tensile modulus, and flexural strength. The tensile strength of the carbon fiber prepregs obtained in preferred embodiments 7 to 9 is 2947 to 3081 MPa, the tensile modulus is 178 to 185 GPa, and the flexural strength is 1524 to 1578 MPa. The difference between the prepregs in Examples 6 to 11 is that the modified epoxy resins are different. The modified epoxy resin of Example 11 does not contain salicylic acid phenol, and the content of salicylic acid phenol in the modified epoxy resins of Examples 6 to 10 is different. It can be concluded that the addition of salicylic acid phenol in the epoxy resin has a great influence on the mechanical properties of the prepreg. When a certain amount of salicylic acid phenol is used instead of bisphenol A to prepare the epoxy resin, the defect of poor toughness of the epoxy resin can be compensated, the toughness of the epoxy resin is improved, thereby improving the toughness of the final product carbon fiber prepreg, and having a good reinforcing effect on the mechanical strength of the material.

[0125] From the interlaminar shear strength data in Table 1, it can be seen that the interlaminar shear strength of the carbon fiber prepreg obtained in the most preferred embodiment 8 of the present application is 134 MPa, and the interlaminar shear strength is relatively high. In Example 11, no salicylic acid phenol is added to the modified epoxy resin. The interlaminar shear strength of Example 11 is quite different from that of Example 8. At the same time, the bending strength of Example 8 is significantly higher than that of Example 11. It can be seen that after the epoxy resin is modified with salicylic acid phenol, the compatibility of the epoxy resin and the carbon fiber can be increased.

[0126] Test Example 3:

[0127] High temperature resistance test of carbon fiber prepreg:

[0128] The carbon fiber prepregs obtained in Examples 6 to 11 were used as samples. The tensile strength of the carbon fiber prepregs at 240°C was tested with reference to GB / T3354-2014 standard. The tensile strength was compared with that obtained in Test Example 2. The retention rate was calculated. The results were as follows: Figure 2 shown.

[0129] Figure 2The results of the high temperature resistance test of the carbon fiber prepregs obtained in Examples 6 to 11 of the present application are compared with the tensile strength at room temperature. The carbon fiber prepregs obtained in the present application can still maintain a high tensile strength at 240°C, and the tensile strength retention rate is higher than 93%, indicating that the carbon fiber prepregs obtained in the present application have excellent high temperature resistance. It can also be seen that the modified epoxy resin of Example 11 does not contain salicylic acid phenol, while the modified epoxy resins of Examples 6 to 10 contain salicylic acid phenol, and the tensile strength retention rate of Example 11 is lower than that of Examples 6 to 10. Moreover, as the content of salicylic acid phenol in the modified epoxy resin increases, the tensile strength retention rate of the material increases. When the molar amount of salicylic acid phenol added is 4% of the epoxy resin, as the content of salicylic acid phenol increases, the tensile strength retention rate of the material decreases. It can be seen that when a certain amount of salicylic acid phenol is added, the high temperature resistance of the carbon fiber prepreg can be significantly improved.

[0130] Test Example 4:

[0131] Wear resistance test of carbon fiber prepreg:

[0132] The carbon fiber prepregs obtained in Examples 12 to 15 and Comparative Examples 2 to 4 were used as samples and abrasion resistance tests were performed according to GB / T1768-2006. The test results are shown in FIG. Figure 3 shown.

[0133] Figure 3 The wear resistance test results of carbon fiber prepreg are as follows: Figure 3 It can be seen that the carbon fiber prepreg prepared using the components described in the present application has high wear resistance. In Comparative Examples 2 to 3, locust bean gum and 4-acetylaminosalicylic acid were not added at the same time, and their wear resistance was significantly lower than that of Examples 8 to 15. It can be seen that adding locust bean gum and 4-acetylaminosalicylic acid to the carbon fiber prepreg at the same time can improve the wear resistance of the material, while the wear resistance of the carbon fiber prepregs of Examples 12 and 15 is lower than that of other examples. It can be seen that when locust bean gum and 4-acetylaminosalicylic acid are added in a certain ratio (1:2 to 2.6), the prepreg can obtain excellent wear resistance.

[0134] Test Example 5:

[0135] Carbon fiber prepreg storage stability test:

[0136] The carbon fiber prepregs obtained in Examples 12 to 15 and Comparative Examples 2 to 4 were used as samples. The viscosity of the prepregs (uncured) was tested using a PICMA Tack Tester II manufactured by Toyo Seiki Co., Ltd. A 18 mm × 18 mm cover glass was pressed against the prepreg with a force of 0.4 kgf for 5 seconds and stretched at a speed of 30 mm / min. The resistance during peeling was measured as the viscosity value. The viscosity of the samples after 0 days, 3 days, and 7 days at room temperature was evaluated according to the following indicators. The changes in viscosity over time were compared to determine storage stability. The judgment criteria were:

[0137] Excellent: The viscosity value is greater than 0.3kg and less than 2.0kg, and the adhesion is moderate;

[0138] Medium: The viscosity value is greater than 0.1kg and less than 0.3kg, or greater than 2.0kg and less than 3.0kg, with slightly stronger or weaker adhesion;

[0139] Poor: The viscosity value is less than 0.2 or greater than 3.0 kg, and the viscosity is too strong or too weak.

[0140] Table 2

[0141]

[0142]

[0143] Table 2 is the storage stability test results of the carbon fiber prepregs obtained in the present application. As shown in Table 2, the carbon fiber prepregs obtained in preferred embodiments 8, 13, and 14 have little viscosity change after being placed at room temperature for 0 days, 3 days, and 7 days, and have high stability. The carbon fiber prepregs obtained in Examples 12 and 15 have a large viscosity change after being placed at room temperature for 7 days. The carbon fiber prepregs obtained in Comparative Examples 2 and 3 have a large viscosity change after being placed at room temperature for 3 days, and the viscosity value is greater than 2.0 kg and less than 3.0 kg. The carbon fiber prepreg obtained in Comparative Example 4 has a viscosity value of less than 0.2 kg after being placed at room temperature for 3 days. It can be seen that adding a certain proportion of locust bean gum and 4-acetylaminosalicylic acid to the carbon fiber prepreg at the same time can improve the storage stability of the material.

[0144] The present application prepares carbon fiber prepreg by adopting the above-mentioned components and methods. Through the coordinated action of each component, the obtained carbon fiber prepreg has excellent mechanical properties, a tensile strength range of 2947~3081MPa, a tensile modulus range of 178~185GPa, a flexural strength range of 1524~1578MPa, high interlaminar shear strength, good compatibility between modified epoxy resin and carbon fiber, excellent high temperature resistance, compared with the tensile strength at room temperature, the tensile strength retention rate at 240°C is as high as 94.6%, good wear resistance, good stability at room temperature, can be stored for a long time, and has broad application prospects.

[0145] The applicant declares that the present invention uses the above-described embodiments to illustrate the detailed process equipment and process flow of the present invention. However, the present invention is not limited to the above-described detailed process equipment and process flow, and does not necessarily rely on the above-described detailed process equipment and process flow in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for the raw materials of the present invention's products, additions of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A carbon fiber prepreg, characterized in that: In parts by weight, it comprises the following components: 30-40 parts by weight of carbon fiber, 35-50 parts by weight of salicylic acid-modified epoxy resin, 12-20 parts by weight of polystyrene butadiene copolymer, 2-3 parts by weight of locust bean gum, 4-7 parts by weight of 4-acetylaminosalicylic acid, 3-5 parts by weight of modified silicon carbide powder, 1-3 parts by weight of curing agent, and 2-5 parts by weight of accelerator; wherein the salicylic acid-modified epoxy resin is prepared by reacting bisphenol A, salicylic acid, and epichlorohydrin under alkaline conditions; the molar ratio of bisphenol A, salicylic acid, and epichlorohydrin is 2-4:0.2-0.4:10; and the added weight ratio of locust bean gum and 4-acetylaminosalicylic acid is 1:2-2.

6.

2. The carbon fiber prepreg according to claim 1, characterized in that Salicylic acid phenol modified epoxy resin is prepared by the following method: Bisphenol A, salaminophenol, epichlorohydrin, and an auxiliary agent are mixed and stirred under N2 protection to completely dissolve; NaOH is then added thereto with a molar ratio of NaOH to epichlorohydrin of 0.2-0.4:1, and the mixture is reacted at 30-50°C for 2-6 hours; the mixture is filtered; the filtrate is allowed to stand for separation, the water layer is removed, and then the product is distilled under reduced pressure to obtain the product.

3. The carbon fiber prepreg according to claim 1, characterized in that The modified silicon carbide powder is prepared from polyether-modified trisiloxane-modified silicon carbide powder.

4. A method for preparing a carbon fiber prepreg, for preparing the carbon fiber prepreg according to any one of claims 1 to 3, characterized in that: include: The salicylic acid modified epoxy resin, polystyrene butadiene copolymer and curing agent are mixed, and stirred at 70-80° C. to obtain a mixed solution; then modified silicon carbide powder and accelerator are added, and stirring is continued at 70-80° C. to obtain a mixed solution; locust bean gum and 4-acetylaminosalicylic acid are added, and stirring is continued at 50-60° C. to obtain a mixed solution; the temperature is raised to 100-120° C., carbon fiber is added, and the carbon fiber is fully impregnated and then taken out and cooled to obtain the obtained solution.

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