Preparation method of polyimide resin composite material

Abstract

The invention provides a preparation method of a polyimide resin composite material. The preparation method comprises the following steps: preparing a polyimide resin solution; preparing the polyimide resin solution into a polyimide resin adhesive film; compounding the polyimide resin adhesive film with a reinforced fiber material to obtain a polyimide resin prepreg; a polyimide resin prepreg is laid on the laying mold, and a polyimide resin prepreg blank is obtained; carrying out first packaging and devolatilization treatment, and extracting reaction micromolecular products generated in the imidization process; and after secondary packaging, curing and molding, cooling and demolding to obtain the polyimide resin composite material. The polyimide resin composite material can be prepared through a vacuum bag forming technology, the dependence on forming equipment is reduced, and the manufacturing cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and more specifically to a method for preparing a polyimide resin composite material. Background Art

[0002] The main chain of polyimide resin molecules contains heat-resistant and stable imide groups, which can form a three-dimensional solidified network through end-group cross-linking reactions. It has excellent heat resistance and mechanical properties. Polyimide resins and their composite materials have also been widely used in advanced manufacturing fields such as aerospace. Since NASA developed PMR-15 polyimide resin in the 1970s, researchers at home and abroad have developed a series of heat-resistant polyimide resins with temperature resistance grades ranging from 316℃ to 426℃, and their composite materials have been widely used in aircraft engine outer ducts and other components.

[0003] Due to the special molecular structure characteristics of polyimide, bubbles and pores caused by the imidization process have become the main difficulties in the composite material molding process. In order to avoid internal defects in composite materials, the current molding of polyimide resin-based composite materials is mainly provided by hot pressing molding methods such as autoclave molding and compression molding to provide molding pressure and curing temperature. This method is also applicable to polyimide material systems with high melt viscosity such as PMR-II-50 and AFR-700B. The process requires the molding equipment to provide a high molding temperature of more than 300°C and a high molding pressure of more than 2MPa. It has strict requirements on equipment and high manufacturing costs. On this basis, the researchers further developed a series of liquid molding methods, using isomeric dianhydride as a synthetic raw material to design and synthesize polyimide resins with low melt viscosity, such as PETI-375 and TriA-X. The corresponding polyimide composite materials can be prepared by liquid molding processes such as RTM, VARTM, VARI, and RFI, but the liquid molding process still requires supporting molding equipment such as heating equipment and injection equipment, and the manufacturing cost is still high.

[0004] Vacuum bag forming is a composite material forming method with low manufacturing cost. At present, the vacuum bag forming method is mainly used for the preparation of epoxy, bismaleimide and other resin composite materials. It is achieved by vacuum resin impregnation or prepreg vacuum bag pressing. The curing process is usually carried out in an oven. It has low equipment dependence, low manufacturing cost and high manufacturing efficiency. However, due to the high melt viscosity, high curing temperature and difficulty in removing volatiles in the imidization process of traditional polyimide resins, the vacuum bag forming method has not yet been applied to the field of polyimide composite material forming. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The technical problem to be solved by the present invention is that when a conventional polyimide resin melt is used to form a composite material through a vacuum bag forming method, there are problems such as high viscosity, high curing temperature, and difficulty in removing volatile components during the imidization process.

[0007] (II) Technical solution

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] In a first aspect, the present invention provides a method for preparing a polyimide resin composite material, comprising the following steps:

[0010] Dissolving an aromatic diamine monomer in an organic solvent and heating the solution to a first preset temperature to obtain an aromatic diamine solution having a mass concentration of 10 wt % to 80 wt %;

[0011] Dissolving phenylethynylphthalic anhydride and aromatic dianhydride in an alcohol solvent and heating to a second preset temperature to obtain an esterification solution with a mass concentration of 10wt%-80wt%;

[0012] The esterification solution is added to the aromatic diamine solution to carry out a polymerization reaction within a third preset temperature range for 1h-4h, and then a vacuum low-pressure polymerization reaction is carried out within a fourth preset temperature range for 1h-2h, and the volatile organic solvent is collected and separated during the reaction process to obtain a polyimide resin solution with a mass concentration of 50wt%-90wt%;

[0013] preparing a polyimide resin film from the polyimide resin solution;

[0014] Compounding the polyimide resin film with a reinforcing fiber material to obtain a polyimide resin prepreg;

[0015] Laying down multiple layers of the polyimide resin prepreg on a laying mold to obtain a polyimide resin prepreg embryo;

[0016] The polyimide resin prepreg body is placed on a vacuum bag forming mold, and the polyimide resin prepreg body is packaged for the first time with a first auxiliary material. After the first packaging is completed, a devolatilization treatment is performed in a high-temperature oven with a first preset process parameter, during which the vacuum bag is used to apply pressure to reduce bubbles and pores, and the reaction small molecule products generated in the imidization process are extracted by vacuuming;

[0017] After the devolatilization treatment is completed, the first auxiliary material is removed, and the polyimide resin prepreg body on the vacuum bag forming mold is packaged for the second time using the second auxiliary material to obtain a vacuum bag forming component;

[0018] The vacuum bag forming assembly is placed in a high-temperature oven, and the polyimide resin prepreg body is heated and cured under the second preset process parameters. After cooling and demolding, a polyimide resin composite material is obtained.

[0019] Preferably, the first preset temperature is 40°C-100°C, the second preset temperature is 40°C-120°C, the third preset temperature is 40°C-120°C, the fourth preset temperature is 80°C-140°C, and the vacuum degree is controlled to be ≤-0.095MPa in the vacuum low-pressure polymerization reaction.

[0020] Preferably, the surface density of the polyimide resin film is 10 g / m 2 -200g / m 2 The mass fraction of the polyimide resin film in the polyimide resin prepreg is 30wt%-60wt%, the composite temperature is 30°C-150°C, and the composite pressure is 0.01MPa-1MPa.

[0021] Preferably, the molar ratio of aromatic diamine, aromatic dianhydride and phenylethynylphthalic anhydride monomers is (n+1):n:2, wherein n is an integer of 1-5.

[0022] Preferably, the aromatic dianhydride monomer includes at least one of 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, and 4,4'-hexafluoroisopropylphthalic anhydride;

[0023] Preferably, the aromatic diamine monomer includes at least one of m-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)diaminobiphenyl, 1,3-bis(4'-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diaminodiphenylmethane, 4,4'-diaminophenyl sulfone, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

[0024] Preferably, the alcohol solvent includes at least one of methanol, ethanol, propanol, isopropanol, n-butanol, and isobutanol;

[0025] Preferably, the organic solvent includes at least one of tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0026] Preferably, the reinforcing fiber material includes at least one of carbon fiber, glass fiber, aramid fiber, polyimide fiber, poly(p-phenylene benzobisoxazole) fiber, basalt fiber, and silicon carbide fiber.

[0027] Preferably, the first preset process parameters include: heating at 30°C-100°C for 0.5h-3h and at 100°C-150°C for 0.5h-3h, and controlling the vacuum degree in the vacuum bag to be ≤-0.1MPa during the whole devolatilization process;

[0028] Preferably, the second preset process parameters include: heating at 180℃-250℃ for 0.5h-5h, 250℃-320℃ for 1h-5h, 320℃-350℃ for 1h-5h, and 350℃-400℃ for 2h-8h, and controlling the vacuum degree in the vacuum bag to be ≤-0.1MPa during the heating and curing molding process.

[0029] Preferably, the first auxiliary material includes vacuum bag film, tape, putty strip, and breathable felt with a use temperature lower than 300°C; the second auxiliary material includes high-temperature vacuum bag film, high-temperature tape, high-temperature putty strip, and high-temperature breathable felt with a use temperature higher than 300°C.

[0030] (III) Beneficial effects

[0031] The above technical solution of the present invention has at least the following advantages:

[0032] 1. The preparation method of the polyimide resin composite material provided by the present invention can prepare a thermosetting polyimide resin with a melt viscosity lower than that of a traditional polyimide resin, and on this basis, a polyimide resin prepreg is prepared. The resin matrix of the polyimide resin prepreg has good fluidity during the devolatilization process, and thus the volatile components of the imidization process can be fully discharged during the vacuum bag pressurization process, so as to reduce the generation of bubbles and pores inside the composite material, so as to ensure that the molding quality of the finally prepared polyimide resin prepreg meets the use requirements.

[0033] 2. Through the preparation method of the polyimide resin composite material provided by the present invention, it is possible to prepare the polyimide resin composite material by adopting the vacuum bag molding technology. Compared with the autoclave molding, compression molding and liquid molding processes in the prior art, the vacuum bag molding technology only requires heating and temperature rise by oven equipment and pressure application by vacuum bag. It has low dependence on high-cost molding equipment such as autoclaves and glue injection machines, can reduce the purchase cost of equipment, does not require high molding temperature and high molding pressure, can reduce energy consumption cost, has relatively simple production process, reduces the time required for molding, improves manufacturing efficiency, and can greatly reduce the manufacturing cost of the polyimide resin composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 This is one of the flow diagrams of the method for preparing the polyimide resin composite material provided by an embodiment of the present invention.

[0036] Figure 2 This is the second schematic flow diagram of the method for preparing the polyimide resin composite material provided by an embodiment of the present invention.

[0037] Figure 3 It is a schematic structural diagram of a vacuum bag forming assembly provided in an embodiment of the present invention.

[0038] Figure 4 This is a photo of the PA-1 polyimide composite material flat plate product provided in Example 1 of the present invention.

[0039] Figure 5 This is an ultrasonic C-scan image of the PA-1 polyimide composite material flat plate product provided in Example 1 of the present invention.

[0040] Figure 6 This is a photo of the EW100A glass cloth reinforced PA-1 polyimide composite material flat plate product provided in Example 2 of the present invention.

[0041] Figure 7 This is an ultrasonic C-scan image of the EW100A glass cloth reinforced PA-1 polyimide composite flat plate product provided in Example 2 of the present invention.

[0042] Figure 8 This is a photo of the PA-1 polyimide composite T-shaped piece provided in Example 3 of the present invention.

[0043] Fig. 9 This is an ultrasonic C-scan image of the PA-1 polyimide composite T-shaped piece provided in Example 3 of the present invention.

[0044] Fig.10 This is a photo of the PF-1 polyimide composite material flat plate product provided in Example 4 of the present invention.

[0045] Fig.11 This is an ultrasonic C-scan image of the PF-1 polyimide composite material flat plate product provided in Example 4 of the present invention.

[0046] The reference numerals in the figures are:

[0047] 1. Polyimide resin prepreg embryo; 2. Vacuum bag molding mold; 3. High-temperature vacuum bag film; 4. High-temperature putty strip; 5. High-temperature breathable felt; 6. High-temperature rubber baffle strip; 7. High-temperature insulation material; 8. Tetrafluoroethylene cloth. DETAILED DESCRIPTION

[0048] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0049] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0050] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one item" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one item of a, b, or c", or "at least one item of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating relative importance or indicating the number of technical features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The specific implementation of the present invention is described in more detail below in conjunction with specific embodiments:

[0052] like Figure 1 , Figure 2 as well as Figure 3 As shown, an embodiment of the present invention provides a method for preparing a polyimide resin composite material, comprising the following steps:

[0053] S1. Dissolve the aromatic diamine monomer in an organic solvent and heat it to a first preset temperature to obtain an aromatic diamine solution with a mass concentration of 10wt%-80wt%; specifically, dissolve the aromatic diamine monomer in an organic solvent, heat it to 40°C-100°C (first preset temperature) under the protection of an inert gas, and obtain an aromatic diamine solution with a concentration of 10wt%-80wt%.

[0054] S2. Dissolve phenylethynylphthalic anhydride and aromatic dianhydride in an alcohol solvent and heat to a second preset temperature to obtain an esterification solution with a mass concentration of 10wt%-80wt%; specifically, dissolve phenylethynylphthalic anhydride and aromatic dianhydride in an alcohol solvent and heat to 40°C-120°C (second preset temperature) to obtain an esterification solution with a concentration of 10wt%-80wt%.

[0055] S3. Add the esterification solution to the aromatic diamine solution and carry out polymerization reaction within the third preset temperature range for 1h-4h, and then carry out vacuum low-pressure polymerization reaction within the fourth preset temperature range for 1h-2h, collect and separate the volatile organic solvent in the reaction process, and obtain a polyimide resin solution with a mass concentration of 50wt%-90wt%; specifically, add the esterification solution to the aromatic diamine solution, stir and heat to 40℃-120℃ (third preset temperature) in a reaction container for polymerization reaction for 1h-4h; further heat to 80℃-140℃ (fourth preset temperature), and carry out vacuum low-pressure polymerization reaction for 1h-2h, with a vacuum degree of ≤-0.095MPa, and collect and separate the volatile organic solvent produced in the reaction process through a condensation device to obtain a polyimide resin solution with a concentration of 50wt%-90wt%. Through the above steps S1 to S3, a polyimide resin solution having a melt viscosity lower than that of a conventional polyimide resin can be obtained, which can then be formed into a polyimide resin film and further compounded with a reinforcing fiber material to form a prepreg.

[0056] S4, preparing a polyimide resin film from the polyimide resin solution; specifically, transferring the polyimide resin solution to a film coating machine for coating, wherein the coating temperature is 30°C-120°C, and the surface density of the polyimide resin film is controlled to be 10g / m 2 -200g / m 2 , and compact and roll it up for use.

[0057] S5. Compounding the polyimide resin film with the reinforcing fiber material to obtain a polyimide resin prepreg.

[0058] S6. Lay multiple layers of polyimide resin prepreg prepared by the preparation method of any one of the polyimide resin composite materials in the above-mentioned embodiments on a paving mold to obtain a polyimide resin prepreg embryo 1; specifically, cut the polyimide resin prepreg into a suitable size according to the target composite material size, lay it layer by layer on the paving mold to a target structural form, and lay it on a vacuum bag molding mold to obtain a polyimide resin prepreg embryo 1.

[0059] S7. Place the polyimide resin prepreg body 1 on the vacuum bag forming mold 2, and use the first auxiliary material to perform the first packaging on the polyimide resin prepreg body. After the first packaging is completed, perform devolatilization treatment in a high-temperature oven with first preset process parameters. During the devolatilization process, the vacuum bag is used to apply pressure to reduce bubbles and pores, and the small molecule reaction products produced by the imidization process are extracted by vacuum extraction; specifically, the first auxiliary material includes a vacuum bag film, tape, putty strip, and breathable felt with a use temperature lower than 300°C. Since polyimide resin has the problem of difficulty in removing volatiles in the imidization process when forming a composite material, the present application performs devolatilization on the polyimide resin prepreg embryo under a suitable first preset process parameter. Since the polyimide resin material prepared by the above steps S1 to S3 has good fluidity, during the devolatilization process, the negative pressure generated by the vacuum bag uniformly presses the polyimide resin material, so that the reaction small molecule products generated in the imidization process can be smoothly discharged from the resin material, and the reaction small molecule products generated in the imidization process are extracted by vacuuming, so as to eliminate the volatiles in the imidization process. At the same time, during the devolatilization process, the negative pressure generated by the vacuum bag uniformly presses the resin material to eliminate the bubbles and pores generated in the imidization process of the polyimide resin material, and improve the molding quality of the composite material. During the devolatilization process, the reaction small molecule products generated in the imidization process will be adsorbed on the first auxiliary material, and the temperature used in the devolatilization process is relatively low, so the first auxiliary material is preferably a relatively cheap room temperature auxiliary material to reduce the loss cost of the material.

[0060] S8, after the devolatilization treatment is completed, the first auxiliary material is removed, and the polyimide resin prepreg embryo on the vacuum bag forming mold is packaged for the second time with the second auxiliary material to obtain a vacuum bag forming component; specifically, the second auxiliary material includes a high-temperature vacuum bag film 3 with a use temperature higher than 300°C, a high-temperature adhesive tape, a high-temperature putty strip 4, a high-temperature insulation material 7, and a high-temperature breathable felt 5, and the stacking order of each material is as follows: Figure 3 As shown. Specifically, during packaging, tetrafluoroethylene cloth 8 is placed on both side surfaces of the polyimide resin prepreg body 1 as a demolding cloth to facilitate demolding after the curing molding is completed. High-temperature rubber baffles 6 are placed at both ends of the polyimide resin prepreg body 1 to limit the two ends of the polyimide resin prepreg body 1, so as to facilitate the molding of the polyimide resin prepreg body 1. Specifically, the polyimide resin prepreg body 1 after the devolatilization treatment is removed, and the second auxiliary material (high-temperature vacuum bag film, high-temperature tape, high-temperature putty strip, high-temperature breathable felt, etc.) is used again to encapsulate the polyimide resin prepreg body after the devolatilization treatment, and the connection between the high-temperature vacuum bag and the vacuum bag molding mold is sealed with a high-temperature sealant, and the high-temperature vacuum bag is clamped around the four sides by an I-shaped clamp to ensure sealing, and a vacuum bag molding assembly is obtained.

[0061] S9, placing the vacuum bag forming assembly in a high-temperature oven, heating and curing the polyimide resin prepreg body under the second preset process parameters, cooling and demolding, and obtaining a polyimide resin composite material. Specifically, the vacuum bag forming assembly obtained in step S8 is transferred to a high-temperature oven for curing treatment, and the prepreg body is cured by heating and molding at 180℃-250℃ for 0.5h-5h, 250℃-320℃ for 1h-5h, 320℃-350℃ for 1h-5h, and 350℃-400℃ for 2h-8h. The vacuum degree in the high-temperature vacuum bag is maintained ≤-0.1MPa by a vacuum pump during the curing process. Turn off the oven heating, keep the vacuum degree cooled to below 60℃ and demold, and obtain a vacuum bag-molded polyimide resin composite material.

[0062] Furthermore, the molar ratio of the aromatic diamine, aromatic dianhydride and phenylethynylphthalic anhydride monomer is (n+1):n:2, wherein n is an integer of 1-5.

[0063] Further, the aromatic dianhydride monomer includes at least one of 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, and 4,4'-hexafluoroisopropylphthalic anhydride;

[0064] Further, the aromatic diamine monomer includes at least one of m-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)diaminobiphenyl, 1,3-bis(4'-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diaminodiphenylmethane, 4,4'-diaminophenylsulfone, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

[0065] Further, the alcohol solvent includes at least one of methanol, ethanol, propanol, isopropanol, n-butanol, and isobutanol;

[0066] Further, the organic solvent includes at least one of tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0067] Further, the reinforcing fiber material includes at least one of carbon fiber, glass fiber, aramid fiber, polyimide fiber, polyparaphenylene benzobisoxazole fiber, basalt fiber, and silicon carbide fiber.

[0068] The following are specific embodiments provided in this application:

[0069] Embodiment 1:

[0070] (1-1) 229.42 g of 1,3-bis(4'-aminophenoxy)benzene was dissolved in 525.32 g of N-methylpyrrolidone solvent, and heated to 60° C. under inert gas protection to obtain an aromatic diamine solution with a concentration of 30 wt %;

[0071] (1-2) dissolving 97.4 g of phenylethynylphthalic anhydride and 173.17 g of 2,3,3',4'-biphenyltetracarboxylic dianhydride in 631.34 g of ethanol solvent and heating to 75° C. to obtain an esterification solution with a concentration of 30 wt %;

[0072] (1-3) adding the esterification solution to the aromatic diamine solution, stirring and heating to 75° C. in a reaction vessel for polymerization reaction for 2 h; further heating to 90° C., and simultaneously performing vacuum low-pressure polymerization reaction for 2 h, controlling the vacuum degree to be ≤-0.095 MPa, collecting and separating the volatile organic solvent produced during the reaction process through a condensation device, and obtaining a PA-1 polyimide resin solution with a concentration of 80 wt %;

[0073] (1-4) The PA-1 polyimide resin solution was transferred to a film coating machine for coating. The coating temperature was 45°C and the surface density of the polyimide resin film was controlled to be 100 g / m 2 and compacting and rolling up for standby use to obtain a polyimide resin film;

[0074] (1-5) After the CCF800H carbon fiber (reinforced fiber material) is spread, it is composited with a polyimide resin film, the mass fraction of the composite polyimide resin film is controlled to be 40wt%, the composite temperature is 55°C, and the composite pressure is 0.1MPa, to obtain a PA-1 polyimide resin prepreg;

[0075] (1-6) Cut the PA-1 polyimide resin prepreg into 350 mm × 330 mm size according to [0] 16 The polyimide resin prepreg body is laid in a flat plate shape in a layering sequence, the polyimide resin prepreg body is laid on a vacuum bag forming mold, and the polyimide resin prepreg body is encapsulated and pre-evacuated for leak testing using a first auxiliary material (normal temperature vacuum bag film, normal temperature tape, normal temperature putty strip, normal temperature breathable felt, etc.); the vacuum bag forming mold on which the polyimide resin prepreg body is laid is transferred to a high-temperature oven for devolatilization treatment, and the heating program is carried out at 70° C. for 1 hour and at 120° C. for 1 hour, and the vacuum degree in the vacuum bag is continuously maintained at ≤-0.1 MPa by a vacuum pump to fully extract the reaction small molecule products;

[0076] (1-7) The polyimide resin prepreg body after the devolatilization treatment is disassembled, the first auxiliary material is removed, and the second auxiliary material (high-temperature vacuum bag film, high-temperature tape, high-temperature putty strip, high-temperature breathable felt, etc.) is used again to encapsulate the composite material flat devolatilization body, and the connection between the high-temperature vacuum bag and the vacuum bag molding mold is sealed with a high-temperature sealant, and the high-temperature vacuum bag is clamped around to ensure the sealing, and the vacuum bag molding assembly is obtained. Then, the vacuum bag molding assembly is transferred to a high-temperature oven for curing treatment, and the devolatilization body is cured by heating and molding at 180°C for 1h, 300°C for 1h, 350°C for 2h, and 380°C for 4h. During the curing process, the vacuum degree in the high-temperature vacuum bag is maintained at ≤-0.1MPa by a vacuum pump, and the temperature is lowered to below 60°C to remove the mold, and the obtained product is as follows. Figure 4 The PA-1 polyimide composite material flat plate product (polyimide resin composite material) shown in Example 1 is subjected to ultrasonic C scanning to obtain the following Figure 5 Ultrasound C-scan shown.

[0077] Embodiment 2:

[0078] (2-1) EW100A glass cloth reinforced PA-1 polyimide resin prepreg was prepared by the same method as in Example 1; that is, the reinforcing fiber material was replaced by EW100A glass cloth from the CCF800H carbon fiber in Example 1, and the remaining materials and steps were the same.

[0079] (2-2) a polyimide resin prepreg body is laid in a flat plate shape according to the [(0 / 90)]8 ply sequence, laid on a vacuum bag forming mold, and the polyimide resin prepreg body is encapsulated and pre-evacuated for leak testing using a first auxiliary material (normal temperature vacuum bag film, normal temperature tape, normal temperature putty strip, normal temperature breathable felt, etc.); the vacuum bag forming mold of the polyimide resin prepreg body is transferred to a high-temperature oven for devolatilization treatment, and the temperature is raised at 75°C for 2h and 120°C for 2h, and the vacuum degree in the vacuum bag is continuously maintained at ≤-0.1MPa by a vacuum pump to fully extract the reaction small molecule products;

[0080] (2-3) The polyimide resin prepreg body after the devolatilization treatment is removed, and the polyimide resin prepreg body is re-packaged with the second auxiliary material (high-temperature vacuum bag film, high-temperature tape, high-temperature putty strip, high-temperature breathable felt, etc.), and the connection between the high-temperature vacuum bag and the vacuum bag molding mold is sealed with a high-temperature sealant, and the high-temperature vacuum bag is clamped on all sides by an I-shaped clamp to ensure sealing, and a vacuum bag molding component is obtained, and then the vacuum bag molding component is transferred to a high-temperature oven for curing treatment. The devolatilization body is cured by heating and molding at 150°C for 0.5h, 280°C for 0.5h, 350°C for 1h, and 380°C for 2h. During the curing process, the vacuum degree in the high-temperature vacuum bag is maintained at ≤-0.1MPa by a vacuum pump, and the temperature is reduced to below 60°C to remove the mold, and the obtained product is as follows: Figure 6 The EW100A glass cloth reinforced PA-1 polyimide composite material flat plate product (polyimide resin composite material) shown in Example 2 is subjected to ultrasonic C scanning to obtain the following Figure 7 Ultrasound C-scan shown.

[0081] Embodiment three:

[0082] (3-1) PA-1 polyimide resin prepreg was prepared by the same preparation method as in Example 1;

[0083] (3-2) The PA-1 polyimide resin prepreg is cut into a size of 600 mm × 80 mm, and a T-shaped polyimide resin prepreg body is laid according to a quasi-isotropic layer, laid on a vacuum bag molding mold, and the polyimide resin prepreg body is encapsulated and pre-evacuated for leak testing using a first auxiliary material (normal temperature vacuum bag film, normal temperature tape, normal temperature putty strip, normal temperature breathable felt, etc.); the vacuum bag molding mold on which the polyimide resin prepreg body is laid is transferred to a high-temperature oven for devolatilization treatment, and the temperature is raised according to 75°C for 3 hours and 150°C for 1 hour, and the vacuum degree in the vacuum bag is continuously maintained at ≤-0.1 MPa by a vacuum pump to fully extract the reaction small molecule products;

[0084] (3-3) The polyimide resin prepreg body after the devolatilization treatment is removed, and the polyimide resin prepreg body is re-packaged with the second auxiliary material (high-temperature vacuum bag film, high-temperature tape, high-temperature putty strip, high-temperature breathable felt, etc.), and the connection between the high-temperature vacuum bag and the vacuum bag molding mold is sealed with a high-temperature sealant, and the high-temperature vacuum bag is clamped on all sides by an I-shaped clamp to ensure sealing, and a vacuum bag molding component is obtained, and then the vacuum bag molding component is transferred to a high-temperature oven for curing treatment. The devolatilization body is cured by heating at 180°C for 2h, 300°C for 2h, 350°C for 2h, and 380°C for 6h. During the curing process, the vacuum degree in the high-temperature vacuum bag is maintained at ≤-0.1MPa by a vacuum pump, and the mold is removed after the temperature is lowered to below 60°C to obtain a product such as Figure 8 The PA-1 polyimide composite T-shaped piece (polyimide resin composite material) shown in Example 3 was subjected to ultrasonic A scanning to obtain the following Fig. 9 Ultrasound A-scan image shown.

[0085] Embodiment 4

[0086] (4-1) dissolving 251.33 g of 9,9-bis(4-aminophenyl)fluorene in 586.43 g of N-methylpyrrolidone solvent, and heating to 80° C. under inert gas protection to obtain an aromatic diamine solution with a concentration of 30 wt %;

[0087] (4-2) 89.52 g of phenylethynylphthalic anhydride and 159.16 g of 2,3,3',4'-biphenyltetracarboxylic dianhydride were dissolved in 580.24 g of ethanol solvent and heated to 75° C. to obtain an esterification solution with a concentration of 30 wt %;

[0088] (4-3) adding the esterification solution to the aromatic diamine solution, stirring and heating to 75° C. in a reaction vessel for polymerization reaction for 2 h; further heating to 90° C., and simultaneously performing vacuum low-pressure polymerization reaction for 2 h, with a vacuum degree of ≤-0.095 MPa, collecting and separating the volatile organic solvent produced during the reaction through a condensation device, and obtaining a PF-1 polyimide resin solution with a concentration of 80 wt%;

[0089] (4-4) The PF-1 polyimide resin solution was transferred to a film coating machine for coating. The coating temperature was 55°C and the surface density of the polyimide resin film was controlled to be 100 g / m 2 and compacting and rolling up for standby use; obtaining a polyimide resin film;

[0090] (4-5) After the CCF800H carbon fiber (reinforced fiber material) is spread, it is composited with a polyimide resin film, the mass fraction of the composite polyimide resin film is controlled to be 40wt%, the composite temperature is 65°C, and the composite pressure is 0.1MPa, to obtain a PF-1 polyimide resin prepreg;

[0091] (4-6) Cut the PF-1 polyimide resin prepreg into 350 mm × 330 mm size according to [0] 16 The polyimide resin prepreg body is laid in a flat plate shape in a layering sequence, laid on a vacuum bag forming mold, and the polyimide resin prepreg body is encapsulated and pre-evacuated for leak testing using a first auxiliary material (normal temperature vacuum bag film, normal temperature tape, normal temperature putty strip, normal temperature breathable felt, etc.); the vacuum bag forming mold on which the polyimide resin prepreg body is laid is transferred to a high-temperature oven for devolatilization treatment, and the heating program is carried out at 80°C for 1 hour and at 130°C for 1 hour, and the vacuum degree in the vacuum bag is continuously maintained at ≤-0.1MPa by a vacuum pump to fully extract the reaction small molecule products;

[0092] (4-7) The polyimide resin prepreg body after the devolatilization treatment is removed, and the second auxiliary material (high-temperature vacuum bag film, high-temperature tape, high-temperature putty strip, high-temperature breathable felt, etc.) is used to re-package the composite material flat devolatilization body, and the connection between the high-temperature vacuum bag and the vacuum bag molding mold is sealed with a high-temperature sealant, and the high-temperature vacuum bag is clamped around to ensure the sealing, and the vacuum bag molding assembly is obtained. Then, the vacuum bag molding assembly is transferred to a high-temperature oven for curing treatment, and the devolatilization body is cured at 180°C for 1h, 280°C for 1h, 350°C for 1h, and 380°C for 6h. During the curing process, the vacuum degree in the high-temperature vacuum bag is maintained at ≤-0.1MPa by a vacuum pump, and the temperature is lowered to below 60°C for demolding. Fig.10 The PF-1 polyimide composite material flat plate product (polyimide resin composite material) shown in Example 1 is subjected to ultrasonic C scanning to obtain the following Fig.11 Ultrasound C-scan shown.

[0093] According to the ultrasonic A scan and ultrasonic C scan of the polyimide resin composite material prepared in Examples 1 to 4, it can be seen that the polyimide resin composite material prepared by the method for preparing the polyimide resin composite material and the method for preparing the polyimide resin composite material provided in the present application has no obvious defects inside and has good molding quality. Specifically, the method for preparing the polyimide resin composite material and the method for preparing the polyimide resin composite material provided in the present application are suitable for the rapid preparation of a thermosetting polyimide resin system with a minimum melt viscosity of ≤1Pa·s.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a polyimide resin composite material, characterized in that: The following steps are involved: Dissolving an aromatic diamine monomer in an organic solvent and heating the solution to a first preset temperature to obtain an aromatic diamine solution having a mass concentration of 10 wt % to 80 wt %; Dissolving phenylethynylphthalic anhydride and aromatic dianhydride in an alcohol solvent and heating to a second preset temperature to obtain an esterification solution with a mass concentration of 10wt%-80wt%; The esterification solution is added to the aromatic diamine solution to carry out a polymerization reaction within a third preset temperature range for 1h-4h, and then a vacuum low-pressure polymerization reaction is carried out within a fourth preset temperature range for 1h-2h, and the volatile organic solvent is collected and separated during the reaction process to obtain a polyimide resin solution with a mass concentration of 50wt%-90wt%; preparing a polyimide resin film from the polyimide resin solution; Compounding the polyimide resin film with a reinforcing fiber material to obtain a polyimide resin prepreg; Laying down multiple layers of the polyimide resin prepreg on a laying mold to obtain a polyimide resin prepreg embryo; The polyimide resin prepreg body is placed on a vacuum bag forming mold, and the polyimide resin prepreg body is packaged for the first time with a first auxiliary material. After the first packaging is completed, a devolatilization treatment is performed in a high-temperature oven with a first preset process parameter, during which the vacuum bag is used to apply pressure to reduce bubbles and pores, and the reaction small molecule products generated in the imidization process are extracted by vacuuming; After the devolatilization treatment is completed, the first auxiliary material is removed, and the polyimide resin prepreg body on the vacuum bag forming mold is packaged for the second time using the second auxiliary material to obtain a vacuum bag forming component; The vacuum bag forming assembly is placed in a high-temperature oven, and the polyimide resin prepreg body is heated and cured under the second preset process parameters. After cooling and demolding, a polyimide resin composite material is obtained.

2. The method for preparing the polyimide resin composite material according to claim 1, characterized in that: The first preset temperature is 40°C-100°C, the second preset temperature is 40°C-120°C, the third preset temperature is 40°C-120°C, the fourth preset temperature is 80°C-140°C, and the vacuum degree is controlled to be ≤-0.095MPa during the vacuum low-pressure polymerization reaction.

3. The method for preparing the polyimide resin composite material according to claim 1, wherein: The surface density of the polyimide resin film is 10 g / m 2 -200g / m 2 The mass fraction of the polyimide resin film in the polyimide resin prepreg is 30wt%-60wt%, the composite temperature is 30°C-150°C, and the composite pressure is 0.01MPa-1MPa.

4. The method for preparing the polyimide resin composite material according to claim 1, characterized in that: The molar ratio of aromatic diamine, aromatic dianhydride and phenylethynylphthalic anhydride monomer is (n+1):n:2, wherein n is an integer of 1-5.

5. The method for preparing the polyimide resin composite material according to claim 1, wherein: The aromatic dianhydride monomer includes at least one of 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, and 4,4'-hexafluoroisopropylphthalic anhydride; And / or the aromatic diamine monomer includes at least one of m-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)diaminobiphenyl, 1,3-bis(4'-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diaminodiphenylmethane, 4,4'-diaminophenylsulfone, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

6. The method for preparing the polyimide resin composite material according to claim 1, wherein: The alcohol solvent includes at least one of methanol, ethanol, propanol, isopropanol, n-butanol, and isobutanol; And / or the organic solvent includes at least one of tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

7. The method for preparing the polyimide resin composite material according to claim 1, characterized in that: The reinforcing fiber material includes at least one of carbon fiber, glass fiber, aramid fiber, polyimide fiber, poly(p-phenylene benzobisoxazole) fiber, basalt fiber, and silicon carbide fiber.

8. The method for preparing the polyimide resin composite material according to claim 1, characterized in that: The first preset process parameters include: heating at 30°C-100°C for 0.5h-3h and at 100°C-150°C for 0.5h-3h, and controlling the vacuum degree in the vacuum bag to be ≤-0.1MPa during the whole devolatilization process; And / or the second preset process parameters include: heating at 180℃-250℃ for 0.5h-5h, 250℃-320℃ for 1h-5h, 320℃-350℃ for 1h-5h, and 350℃-400℃ for 2h-8h, and controlling the vacuum degree in the vacuum bag to ≤-0.1MPa during the heating and curing molding process.

9. The method for preparing the polyimide resin composite material according to claim 1, characterized in that: The first auxiliary materials include vacuum bag films, tapes, putty strips, and breathable felts with a use temperature lower than 300°C; the second auxiliary materials include high-temperature vacuum bag films, high-temperature tapes, high-temperature putty strips, and high-temperature breathable felts with a use temperature higher than 300°C.

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