A kind of porosity gradient change's heat-proof and heat-insulation integrated hybrid resin matrix composite material and its preparation method

Abstract

The present application relates to a kind of gas hole rate gradient changes and the preparation method of heat-proof integrated hybrid resin-based composite material, select organic-inorganic hybrid resin as matrix, by adding different volume fraction of pore-forming solvent, design 5-8 kinds of resin volume fraction gradually increasing resin solution;Using oscillation vacuum and oscillation pressure assisted RTM process, the solution of the lowest resin volume fraction is first injected into orthogonal three-dimensional fiber preform, and curing and drying treatment is carried out;Then multiple cycle injection glue-curing-drying process, in turn, the remaining resin solution is injected into orthogonal three-dimensional fiber preform according to the resin volume fraction from low to high, the gas hole rate gradient changes of heat-proof integrated hybrid resin-based composite material with low surface porosity and high internal porosity is prepared.Compared with prior art, the composite material of the present application can realize low density, low thermal conductivity, ablation-resistant and other functions in a single structure, and can be applied to aerospace vehicle thermal protection materials.

Description

Technical Field

[0001] This invention relates to the field of resin-based thermal protection materials, and in particular to a hybrid resin-based composite material with a gradient porosity for both thermal insulation and protection, and its preparation method. Background Technology

[0002] Thermal protection materials are the cornerstone of ensuring the safe operation of spacecraft in extreme environments. Among them, resin-based thermal protection materials are currently the most mature, lowest-cost, and have the shortest preparation cycle. Low-porosity resin-based composites exhibit good ablation resistance, but their high thermal conductivity cannot meet the long-term thermal insulation requirements of spacecraft with high Mach speeds and long flight durations. High-porosity resin-based composites, while possessing lower thermal conductivity, suffer from poor ablation resistance. Therefore, the development of integrated low-density, low-thermal-conductivity, and ablation-resistant resin-based composites is an urgent need in this field. Summary of the Invention

[0003] The purpose of this invention is to provide a hybrid resin-based composite material with a gradient porosity for heat insulation and a method for its preparation, which has the advantages of low density, low thermal conductivity and ablation resistance.

[0004] The objective of this invention can be achieved through the following technical solution: a method for preparing a composite material with gradient porosity for integrated heat insulation and waterproofing, comprising the following steps:

[0005] S1: Select organic-inorganic hybrid resin as the matrix, and prepare resin solutions with gradually increasing volume fractions of 5 to 8 hybrid resins by adding pore-forming solvents of different volume fractions.

[0006] S2: The resin solution with the lowest resin volume fraction is first injected into the orthogonal triaxial fiber preform, and then cured and dried.

[0007] S3: The remaining resin solution is injected into the orthogonal triaxial fiber preform in sequence according to the resin volume fraction from low to high. After each injection, curing and drying are performed to finally obtain the heat-insulating integrated hybrid resin-based composite material with varying porosity.

[0008] In this invention, the organic-inorganic hybrid resin exhibits superior high-temperature resistance and a higher carbon residue compared to traditional resins, which is beneficial for improving the ablation resistance of thermal protection materials. The added pore-forming solvent can volatilize during the resin curing process, causing the resin to form a porous structure, which helps to reduce the thermal conductivity and density of the thermal protection material.

[0009] Preferably, the resin solution is injected into the orthogonal triaxial fiber preform using an RTM process assisted by oscillating vacuum and oscillating pressure.

[0010] More preferably, the preparation method of the integrated heat-insulating and air-resistant hybrid resin-based composite material with varying porosity includes the following steps:

[0011] (1) Select organic-inorganic hybrid resin as the matrix, and design 5 to 8 kinds of resin solutions with gradually increasing volume fraction of hybrid resin by adding pore-forming solvents of different volume fractions.

[0012] (2) Select orthogonal triaxial fiber preforms with isotropic characteristics.

[0013] (3) Using an RTM process assisted by oscillating vacuum and oscillating pressure, the solution with the lowest resin volume fraction is first injected into the fiber preform, followed by curing and drying. Then, the injection-curing-drying process is repeated multiple times, with the remaining resin solution injected into the fiber preform sequentially according to the resin volume fraction from low to high. A thermal insulation integrated hybrid resin-based composite material with a porosity gradient of low surface porosity and high internal porosity is prepared.

[0014] In the aforementioned glue injection-curing-drying process, preferably, the initial glue injection time is 8 to 10 hours, and the subsequent glue injection time decreases by 30 to 40 minutes each time.

[0015] In the aforementioned adhesive injection-curing-drying process, preferably, the curing time for each step is 12–24 hours, the initial curing temperature is 90–110°C, and the subsequent curing temperature increases by 2–5°C each time. The drying time for each step is 12–24 hours, the initial drying temperature is 120–130°C, and the subsequent drying temperature increases by 2–5°C each time.

[0016] More preferably, in the RTM process assisted by oscillating vacuum and oscillating pressure, the vacuum value of the vacuum pump is not a constant value, but an alternating value. The vacuum value of the vacuum pump is set to be no less than -0.085MPa, the vacuum alternation amplitude is 4 to 12% of the set vacuum value, and the alternation frequency is 0.2 to 0.9Hz.

[0017] More preferably, in the RTM process assisted by oscillating vacuum and oscillating pressure, the pressure inside the resin container is not a constant value, but an alternating pressure. The pressure of the resin container is set to 0.6 to 1.5 MPa, the pressure alternation amplitude is 4% to 12% of the set container pressure value, and the alternation frequency is 0.2 to 0.9 Hz.

[0018] This invention employs an RTM process assisted by oscillating vacuum and oscillating pressure. The solution with the lowest resin volume fraction is first injected into an orthogonal triaxial fiber preform, followed by curing and drying. Then, the remaining resin solution is injected into the fiber preform in a series of cycles of injection-curing-drying, with the resin volume fraction increasing sequentially. This allows for the preparation of a hybrid resin-based composite material with a porosity gradient—low ​​surface porosity and high internal porosity—that integrates thermal insulation and heat protection. By reducing porosity only on the surface of the material in contact with heat flow, the ablation resistance can be improved without affecting the overall thermal conductivity and density of the material, thus achieving a low-density, low-thermal-conductivity, and ablation-resistant integrated function for resin-based thermal protection materials.

[0019] Preferably, the organic-inorganic hybrid resin in step S1 includes organosilicon hybrid phenolic resin, polycarbosilane hybrid phenolic resin, and organosilicon hybrid polyimide.

[0020] Preferably, the pore-forming solvent in step S1 includes ethanol, isopropanol, cyclohexane, ethylene glycol, and ethyl acetate.

[0021] Preferably, the volume of the pore-forming solvent in step S1 accounts for 60% to 70% of the total volume of the resin and the pore-forming solvent, and is designed to decrease by 4% to 6% each time, while designing resin solutions with gradually increasing volume fractions of 4 to 7 other hybrid resins.

[0022] Preferably, the initial injection time of the resin solution is 8 to 10 hours, and the subsequent injection time is reduced by 30 to 40 minutes each time.

[0023] Preferably, the curing time is 12-24 hours each time, the initial curing temperature is 90-110℃, and the subsequent curing temperature increases by 2-5℃ each time; the drying time is 12-24 hours each time, the initial drying temperature is 120-130℃, and the subsequent drying temperature increases by 2-5℃ each time.

[0024] Preferably, the orthogonal triaxial fiber preform in step S2 includes quartz fiber, carbon fiber, silicon carbide fiber, and mullite fiber.

[0025] Preferably, the density of the orthogonal triaxial fiber preform is 0.4 g / cm³. 3 ~0.7g / cm 3 Within the range.

[0026] A hybrid resin-based composite material with varying porosity for both heat insulation and thermal protection was prepared using the method described above.

[0027] Application of a composite material with a gradient porosity for thermal insulation and heat protection: the composite material is used for thermal protection of spacecraft.

[0028] The resin-based composite material prepared by this invention can achieve multiple functions such as low density, low thermal conductivity, and ablation resistance under a single structure, and can be applied to thermal protection materials for spacecraft.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. This invention proposes a hybrid resin-based composite material with varying porosity for both thermal insulation and heat protection, and its preparation method, which can solve the problem that traditional resin-based thermal protection materials cannot simultaneously possess low density, low thermal conductivity, and ablation resistance.

[0031] 2. The orthogonal triaxial fiber preform of this invention can make the composite material exhibit isotropic characteristics and excellent comprehensive performance in all directions; at the same time, the orthogonal triaxial fiber preform has high stiffness, which can avoid deformation and shrinkage of the composite material during multiple injection-curing-drying processes, and improve the heat insulation and ablation resistance of the material.

[0032] 3. This invention selects an organic-inorganic hybrid resin as the matrix and designs 5-8 resin solutions with gradually increasing resin volume fractions by adding pore-forming solvents of different volume fractions. Through multiple cycles of injection-curing-drying processes, the resin solutions are sequentially injected into the fiber preform according to the resin volume fraction, from low to high. Solutions with low resin volume fractions can fill the entire fiber preform; as the resin volume fraction increases, the injection depth gradually decreases, resulting in a resin-based composite material with a porosity gradient of low surface porosity and high internal porosity. This improves the ablation resistance without affecting the overall thermal conductivity and density of the material. Thus, it achieves an integrated function of low density, low thermal conductivity, and ablation resistance in resin-based thermal protection materials.

[0033] 4. The present invention employs an RTM process assisted by oscillating vacuum and oscillating pressure, which can more uniformly impregnate the resin into the fiber preform, thus improving the ablation resistance of the thermal protection material. At the same time, gradually reducing the injection time and gradually increasing the curing and drying temperatures can facilitate the formation of resin-based composite materials with varying porosity. Attached Figure Description

[0034] Figure 1 A schematic diagram illustrating the preparation process of a heat-insulating integrated hybrid resin-based composite material with varying porosity.

[0035] Figure 2 This is a schematic diagram of the structure of the thermal insulation integrated hybrid resin-based composite material with varying porosity of the present invention. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0037] A hybrid resin-based composite material with varying porosity for both thermal insulation and air resistance, and its preparation method, such as... Figure 1 As shown, an organic-inorganic hybrid resin was selected as the matrix. Five to eight resin solutions with progressively increasing resin volume fractions were designed by adding different volume fractions of pore-forming solvent. An orthogonal triaxial fiber preform with isotropic characteristics was selected. Using an RTM process assisted by oscillating vacuum and oscillating pressure, the solution with the lowest resin volume fraction was first injected into the fiber preform, followed by curing and drying. Then, the injection-curing-drying process was repeated multiple times, with the remaining resin solutions injected into the fiber preform sequentially according to increasing resin volume fractions. The resulting product was as shown in the image. Figure 2 The image shows a thermal insulation integrated hybrid resin-based composite material with a porosity gradient, characterized by low surface porosity and high internal porosity.

[0038] The following detailed description is based on specific embodiments.

[0039] Example 1

[0040] Step 1: Select organosilicon hybrid phenolic resin as the matrix, which is prepared according to patent ZL201911266938.7. Ethanol is selected as the pore-forming solvent;

[0041] Step 2: Set the volume of the pore-forming solvent to 60% of the total volume of the resin and pore-forming agent. Design four other resin solutions with pore-forming solvent volume fractions decreasing by 4% sequentially: 56%, 52%, 48%, and 44%.

[0042] Step 3: Select a density of 0.4 g / cm³ 3 Orthogonal triaxial quartz fiber.

[0043] Step 4: Using an RTM process assisted by oscillating vacuum and oscillating pressure, the solution with the lowest resin volume fraction is first injected into the fiber preform. The vacuum pump is set to -0.085 MPa, the vacuum alternation amplitude is 4% of the set vacuum value, and the alternation frequency is 0.2 Hz. The container pressure is set to 0.6 MPa, the pressure alternation amplitude is 4% of the set container pressure value, the alternation frequency is 0.2 Hz, and the injection time is 8 hours.

[0044] Step 5: Place the mold after injection into a 90℃ oven to cure for 12 hours; then demold and place it in a 120℃ oven to dry for 12 hours.

[0045] Step 6: Repeat the above injection-curing-drying process, injecting the remaining resin solution into the fiber preform sequentially according to the resin volume fraction from low to high. Decrease the injection time by 30 minutes each time, increase the curing temperature by 2°C each time, and increase the drying temperature by 2°C each time.

[0046] Example 2

[0047] Step 1: Select polycarbosilane hybrid phenolic resin as the matrix, which is prepared according to patent ZL202111389268.5. Isopropanol is selected as the pore-forming solvent;

[0048] Step 2: Set the volume of the pore-forming solvent to 65% of the total volume of the resin and pore-forming agent. Design six other resin solutions with pore-forming solvent volume fractions decreasing by 5% sequentially, including 60%, 55%, 50%, 45%, 40%, and 35%.

[0049] Step 3: Select a density of 0.5 g / cm³ 3 Orthogonal triaxial carbon fiber.

[0050] Step 4: Using an RTM process assisted by oscillating vacuum and oscillating pressure, the solution with the lowest resin volume fraction is first injected into the fiber preform. The vacuum pump is set to -0.09 MPa, the vacuum alternation amplitude is 8% of the set vacuum value, and the alternation frequency is 0.7 Hz. The container pressure is set to 1.0 MPa, the pressure alternation amplitude is 8% of the set container pressure value, the alternation frequency is 0.7 Hz, and the resin injection time is 9 hours.

[0051] Step 5: Place the mold after injection into a 100℃ oven to cure for 16 hours; then demold and place it in a 125℃ oven to dry for 16 hours.

[0052] Step 6: Circulating resin injection-curing-drying process: The remaining resin solution is injected into the fiber preform sequentially, from lowest to highest resin volume fraction. The injection time decreases by 35 minutes each time, the curing temperature increases by 3°C each time, and the drying temperature increases by 3°C each time.

[0053] Example 3

[0054] Step 1: Select organosilicon hybrid polyimide as the matrix, the organosilicon hybrid polyimide resin being prepared according to patent ZL201811097472.8. Ethylene glycol is selected as the pore-forming solvent;

[0055] Step 2: Set the volume of the pore-forming solvent to 70% of the total volume of the resin and pore-forming agent. Design seven other resin solutions with pore-forming solvent volume fractions decreasing by 6% sequentially, including 63%, 56%, 49%, 42%, 35%, 28%, and 21%.

[0056] Step 3: Select a density of 0.7 g / cm³ 3 Orthogonal triaxial silicon carbide fibers are used as fiber reinforcements.

[0057] Step 4: Using an RTM process assisted by oscillating vacuum and oscillating pressure, the solution with the lowest resin volume fraction is first injected into the fiber preform. The vacuum pump is set to -0.095 MPa, the vacuum alternation amplitude is 12% of the set vacuum value, and the alternation frequency is 0.9 Hz. The container pressure is set to 1.5 MPa, the pressure alternation amplitude is 12% of the set container pressure value, the alternation frequency is 0.9 Hz, and the resin injection time is 10 hours.

[0058] Step 5: Place the mold after injection into an oven at 110℃ for 24 hours to cure; then demold and place it in an oven at 130℃ for 24 hours to dry.

[0059] Step 6: Circulating resin injection-curing-drying process: The remaining resin solution is injected into the fiber preform sequentially, from lowest to highest resin volume fraction. The injection time decreases by 40 minutes each time, the curing temperature increases by 5°C each time, and the drying temperature increases by 5°C each time.

[0060] Comparative Example 1

[0061] Step 1: Select organosilicon hybrid phenolic resin as the matrix, which is prepared according to patent ZL201911266938.7. Ethanol is selected as the pore-forming solvent;

[0062] Step 2: Set the volume of the pore-forming solvent to be 60% of the total volume of the resin and pore-forming agent.

[0063] Step 3: Select a density of 0.4 g / cm³ 3 Orthogonal triaxial quartz fiber.

[0064] Step 4: Using an RTM process assisted by oscillating vacuum and oscillating pressure, the solution with the lowest resin volume fraction is first injected into the fiber preform. The vacuum pump is set to -0.085 MPa, the vacuum alternation amplitude is 4% of the set vacuum value, and the alternation frequency is 0.2 Hz. The container pressure is set to 0.6 MPa, the pressure alternation amplitude is 4% of the set container pressure value, the alternation frequency is 0.2 Hz, and the injection time is 8 hours.

[0065] Step 5: Place the mold after injection into a 90℃ oven to cure for 12 hours; then demold and place it in a 120℃ oven to dry for 12 hours.

[0066] Comparative Example 2

[0067] Step 1: Select organosilicon hybrid polyimide as the matrix, wherein the organosilicon hybrid polyimide resin is prepared according to patent ZL201811097472.8. No pore-forming solvent is added;

[0068] Step 2: Select a density of 0.7 g / cm³ 3 Orthogonal triaxial silicon carbide fibers are used as fiber reinforcements.

[0069] Step 3: Using an RTM process assisted by oscillating vacuum and oscillating pressure, the solution with the lowest resin volume fraction is first injected into the fiber preform. The vacuum pump is set to -0.095 MPa, the vacuum alternation amplitude is 12% of the set vacuum value, and the alternation frequency is 0.9 Hz. The container pressure is set to 1.5 MPa, the pressure alternation amplitude is 12% of the set container pressure value, the alternation frequency is 0.9 Hz, and the resin injection time is 10 hours.

[0070] Step 4: Place the mold after injection into an oven at 110℃ for 24 hours to cure; then demold and place it in an oven at 130℃ for 24 hours to dry.

[0071] Table 1 summarizes the properties of the integrated heat-insulating and waterproof hybrid resin-based composite materials with varying porosity obtained in Examples 1-3 and the resin-based composite materials obtained in Comparative Examples 1-2. Density was tested using GB 1463-2005, thermal conductivity using GBT 10295-2008, and linear ablation rate using GJB 323B-2018.

[0072] Table 1

[0073]

[0074] By comparing Example 1 and Comparative Example 1, it can be found that designing the resin-based thermal protection material with a structure of varying porosity can significantly improve the ablation resistance performance with less impact on thermal conductivity compared to a uniform porous resin-based composite material.

[0075] By comparing Example 3 and Comparative Example 2, it can be found that designing the resin-based thermal protection material with a structure of varying porosity can significantly improve the thermal insulation performance with less impact on ablation resistance compared to dense resin-based composite materials.

[0076] The material obtained by this invention has low density, low thermal conductivity and low linear ablation rate, and has broad application prospects in thermal protection materials for spacecraft.

[0077] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for producing a thermal barrier integrated hybrid resin matrix composite material having a porosity gradient, characterized by, The method comprises the following steps: S1: selecting an organic-inorganic hybrid resin as a matrix, and preparing five to eight resin solutions with gradually increased volume fractions of the hybrid resin by adding different volume fractions of pore-forming solvents; S2: resin solution with the lowest volume fraction of resin is first injected into an orthogonal three-dimensional fiber preform with isotropic characteristics, and curing and drying treatment is performed; the density of the orthogonal three-dimensional fiber preform is in the range of 0.4 g / cm 3 0.7 g / cm 3 ; S3: sequentially injecting the remaining resin solutions into the orthogonal three-directional fiber preform according to the volume fractions of the resins from low to high, and performing curing and drying treatment after each injection, to finally obtain the heat protection and insulation integrated hybrid resin matrix composite with a gradient change in porosity; The organic-inorganic hybrid resin in step S1 includes organic silicon hybrid phenolic resin, polycarbosilane hybrid phenolic resin and organic silicon hybrid polyimide; the volume fraction of the pore-forming solvent accounts for 60% to 70% of the total volume of the resin and the pore-forming solvent, and is designed to decrease by 4% to 6% each time, and four to seven other resin solutions with gradually increased volume fractions of the hybrid resin are designed; The resin solution is injected for 8 to 10 hours for the first time, and the injection time is decreased by 30 minutes to 40 minutes each time subsequently; the curing time is 12 to 24 hours each time, the curing temperature is 90 to 110 DEG C for the first time, and the curing temperature is increased by 2 to 5 DEG C each time subsequently; the drying time is 12 to 24 hours each time, the drying temperature is 120 to 130 DEG C for the first time, and the drying temperature is increased by 2 to 5 DEG C each time subsequently; The resin solution is injected into the orthogonal three-directional fiber preform by using the RTM process assisted by oscillation vacuum and oscillation pressure; in the RTM process assisted by oscillation vacuum and oscillation pressure, the vacuum value of the vacuum pump is not less than -0.085 MPa, the vacuum alternating amplitude is 4% to 12% of the set vacuum value, and the alternating frequency is 0.2 to 0.9 Hz; in the RTM process assisted by oscillation vacuum and oscillation pressure, the pressure of the resin container is 0.6 to 1.5 MPa, the pressure alternating amplitude is 4% to 12% of the set container pressure value, and the alternating frequency is 0.2 to 0.9 Hz; The heat protection and insulation integrated hybrid resin matrix composite with a gradient change in porosity has low surface porosity and high internal porosity; and the composite is used for the thermal protection of a spacecraft.

2. The method of claim 1, wherein the method is characterized by: The pore-forming solvent in step S1 includes ethanol, isopropyl alcohol, cyclohexane, ethylene glycol and ethyl acetate.

3. The method of claim 1, wherein the method is characterized by: The types of the orthogonal three-directional fiber preform in step S2 include quartz fiber, carbon fiber, silicon carbide fiber and mullite fiber.

4. A hybrid resin matrix composite material with integrated thermal insulation with porosity gradient variation, characterized by, The method is prepared by using the preparation method in any one of claims 1 to 3.

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