Heat insulation and ablation resistance integrated aerogel and preparation method thereof

Abstract

The invention relates to thermal insulation and ablation resistance integrated aerogel and a preparation method thereof. The method comprises the following steps: adding thermoplastic phenolic resin and boron phenolic resin into an organic solvent to obtain a phenolic resin solution; adding organic silicon resin and the pH adjusting liquid into the phenolic resin solution to obtain a resin solution containing silicon and boron; adding a zirconium source into the silicon-boron-containing resin solution to obtain a silicon-boron-zirconium-containing resin solution; adding hexamethylenetetramine into the silicon-boron-zirconium-containing resin solution to obtain a curable reaction solution; placing the curable reaction liquid in a sealed container, and curing at low temperature to obtain silicon-boron-zirconium modified phenolic resin wet gel; carrying out gradient drying treatment on the silicon-boron-zirconium modified phenolic resin wet gel to obtain silicon-boron-zirconium modified phenolic aerogel; the aerogel prepared by the preparation method of the thermal insulation and ablation resistance integrated aerogel has the characteristics of small shrinkage rate, high compression strength, good ablation resistance, low thermal conductivity and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of aerogels, and in particular to a heat-insulating and ablation-resistant integrated aerogel and a preparation method thereof. Background Art

[0002] During the high-speed flight of aerospace vehicles, the outer surface of the aircraft will generate a lot of heat in a short time due to the start-up heating. In order to absorb this heat and reduce the weight of the aircraft as much as possible to improve the energy release efficiency, the outer surface of the aircraft needs to be prepared with lightweight ablation-resistant thermal insulation materials. Phenolic resin, as a common ablation-resistant resin, begins to crack at 400°C, and cracking can absorb a lot of heat. However, after high-temperature cracking, phenolic resin becomes carbonized, and its physical structure will disappear. Therefore, other materials that are more resistant to ablation need to be added. Silicon has good ablation resistance because silicon forms silicon dioxide with extremely high bond energy after oxidation, which can absorb more heat. Therefore, adding silicon to phenolic resin and making it into a lightweight, ablation-resistant material with certain mechanical strength has become a major shell in the thermal protection system of aerospace vehicles, and phenolic aerogel and inorganic element modified phenolic aerogel have also come into being. At the same time, with the continuous improvement of the Mach number and endurance of aircraft, the performance requirements for thermal protection materials are also constantly increasing. Therefore, lightweight, high-strength, ablation-resistant aerogel and its composite materials have become a research hotspot at present.

[0003] CN110903447A discloses a method for preparing an organosilicon-modified phenolic aerogel, which comprises mixing phenols, aldehydes, and post-silicon in proportion, adding water to prepare a solution with a certain mass fraction, adding acid and alkali, controlling the pH value to be 3.5-6.5, curing the organosilicon phenolic at 60-80°C for 5-8h, and obtaining the organosilicon-modified phenolic aerogel by drying at normal pressure. The preparation raw materials of this method are easy to obtain, the process is simple, and the cycle is short, but the thermal conductivity of the obtained aerogel is 0.12W / (m·k), which is relatively high.

[0004] CN117024834A discloses a silicon-zirconium chemically modified phenolic aerogel and a preparation method thereof, which uses linear phenolic as the main raw material, adds organic zirconium and silane, uses hexamethylenetetramine as a catalyst, uses anhydrous ethanol as a reaction solvent, and dries at room temperature to obtain a silicon-zirconium dual-element modified anti-ablation phenolic aerogel. The preparation process of this method is simple, but the required high-pressure reactor is used as a container, and the curing reaction temperature must reach a maximum of 120°C. CN117683322A discloses a flexible thermal insulation composite material based on elastic reinforcement and a preparation method thereof, firstly, a composite material is made of organic silicon resin or silicone rubber and fiber, and then a layer of organic silicon modified phenolic solution is impregnated on the surface, and a flexible silicon modified phenolic aerogel composite material is prepared after curing. Although the flexibility of the prepared composite material has been greatly improved, the complicated preparation process and long preparation cycle are the biggest limitations of its industrial production. The above-mentioned preparation methods, whether through physical blending, copolymerization modification, in-situ polymerization chemical modification, or preparation of multi-level structured modified phenolic composite materials, will have the following problems: 1) In the existing preparation methods, there is not much difference in performance between the phenolic aerogels obtained by physical modification and chemical modification, and it is difficult to meet the thermal protection requirements of aerospace vehicles. 2) In the existing preparation methods, the process of preparing modified phenolic aerogels lacks effective observation and characterization methods, so there is a lack of in-depth understanding of the mechanism and key conditions of aerogel formation.

[0005] Therefore, in view of the above problems, the present invention urgently needs to provide a thermal insulation and ablation-resistant integrated aerogel and a preparation method thereof. Summary of the invention

[0006] The purpose of the present invention is to provide a thermal insulation and ablation-resistant integrated aerogel and a preparation method thereof, and the thermal insulation and ablation-resistant integrated aerogel preparation method is used to solve the technical problem that the existing phenolic aerogels obtained by physical modification and chemical modification in the prior art have little difference in performance and are difficult to meet the thermal protection requirements of aerospace vehicles.

[0007] The present invention provides a method for preparing a heat-insulating and ablation-resistant integrated aerogel, comprising the following steps:

[0008] Thermoplastic phenolic resin and boron phenolic resin are added into an organic solvent and dissolved at low temperature to obtain a phenolic resin solution;

[0009] Adding organic silicon resin and pH adjusting liquid to the phenolic resin solution, dissolving at low temperature, and obtaining a silicon-boron containing resin solution;

[0010] Adding a zirconium source to a silicon-boron-containing resin solution and dissolving it at low temperature to obtain a silicon-boron-zirconium-containing resin solution;

[0011] Adding hexamethylenetetramine to the silicon-boron-zirconium resin solution and dissolving it at low temperature to obtain a curable reaction solution;

[0012] The curable reaction liquid is placed in a sealed container and cured at low temperature to obtain a silicon-boron-zirconium modified phenolic resin wet gel;

[0013] The silicon boron zirconium modified phenolic resin wet gel is subjected to gradient drying to obtain silicon boron zirconium modified phenolic resin aerogel.

[0014] Preferably, the curing temperature of the curable reaction liquid is 60-90°C and the curing time is 20-50h;

[0015] The low temperature dissolution temperature of thermoplastic phenolic resin and boron phenolic resin is 40-50℃;

[0016] The low-temperature dissolution temperature of phenolic resin solution and silicone resin is 40-50°C.

[0017] Preferably, the mass ratio of the thermoplastic phenolic resin to the organic solvent is 1:(1.2-4); the mass ratio of the thermoplastic phenolic resin to the boron phenolic resin is 1:(0.1-0.3).

[0018] Preferably, the mass ratio of the silicone resin to the thermoplastic phenolic resin is (0.1-0.25):1.

[0019] Preferably, the mass ratio of the zirconium source to the silicone resin is (0.2-0.6):1.

[0020] Preferably, the mass ratio of hexamethylenetetramine to thermoplastic phenolic resin is (0.14-0.25):1.

[0021] Preferably, the molecular weight of the boron phenolic resin is 3000-5000, and the boron content is 2%-10%.

[0022] Preferably, the molecular weight of the thermoplastic phenolic resin is 3000-5000;

[0023] The molecular weight of silicone resin is 1000-2500, and its active functional group is silicon-oxygen bond;

[0024] The gradient drying of the silicon-modified phenolic wet gel is divided into two temperature gradients, the first temperature gradient is 20-40°C, the second temperature gradient is 70-90°C, and the drying time of each gradient is 24h;

[0025] The pH adjusting liquid is an acidic adjusting liquid or an alkaline adjusting liquid.

[0026] Preferably, the organic solvent is one of anhydrous ethanol, ethylene glycol or isopropanol; and the zirconium source is one of zirconium nitrate, zirconium sulfate and zirconium oxychloride.

[0027] The present invention also provides a silicon-boron-zirconium modified phenolic aerogel obtained based on the method for preparing the thermal insulation and ablation-resistant integrated aerogel as described in any one of the above.

[0028] The thermal insulation and ablation-resistant integrated aerogel and its preparation method provided by the present invention have the following improvements compared with the prior art:

[0029] 1. The present invention introduces three materials: boron phenolic resin, silicone resin and inorganic zirconium source. The cured boron phenolic resin and the main phenolic resin form a physical entanglement, which improves the ablation resistance of the aerogel; the silicone resin and the main phenolic resin are tightly combined in the form of chemical bonds, which greatly improves the thermal insulation capacity of the aerogel; the inorganic zirconium source is doped into the boron silicon modified organic skeleton, which further improves the thermal insulation and ablation resistance of the aerogel, making it possible to be used in thermal insulation and ablation components in aerospace vehicles.

[0030] 2. The method for preparing the thermally insulating and ablation-resistant integrated aerogel provided by the present invention can achieve consistency in the curing rates of different components by setting the raw material ratio and curing conditions, thereby reducing the final curing temperature to below 90°C. It does not involve high temperature and high pressure reactions, thereby reducing the requirements for production equipment.

[0031] 3. The method for preparing the heat-insulating and ablation-resistant integrated aerogel provided by the present invention produces less or no volatilization of highly toxic gases during the implementation process, and has less impact on the health of the operator. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 This is a physical picture of the heat-insulating and ablation-resistant integrated gas condensate obtained in Example 1;

[0034] Figure 2 This is a scanning electron microscope image of the heat-insulating and ablation-resistant integrated gas condensation obtained in Example 1;

[0035] Figure 3 This is a scanning electron microscope image of the heat-insulating and ablation-resistant integrated gas condensation obtained in Example 1;

[0036] Figure 4 Thermogravimetric diagram of the heat-insulating and ablation-resistant integrated gas condensation obtained in Example 1;

[0037] Figure 5 This is a physical picture of the heat-insulating and ablation-resistant integrated gas condensate obtained in Example 2;

[0038] Figure 6 This is a scanning electron microscope image of the heat-insulating and ablation-resistant integrated gas condensation obtained in Example 2;

[0039] Figure 7 This is a scanning electron microscope image of the heat-insulating and ablation-resistant integrated gas condensation obtained in Example 2;

[0040] Figure 8 This is the thermogravimetric diagram of the thermal insulation and ablation-resistant integrated gas condensation obtained in Example 2. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The present invention provides a method for preparing a heat-insulating and ablation-resistant integrated aerogel, comprising the following steps:

[0043] S1) adding thermoplastic phenolic resin and boron phenolic resin into an organic solvent and dissolving them at low temperature to obtain a phenolic resin solution;

[0044] S2) adding an organosilicon resin and a pH adjusting solution to the phenolic resin solution, dissolving at low temperature, and obtaining a silicon-boron-containing resin solution;

[0045] S3) adding a zirconium source to the silicon-boron-containing resin solution and dissolving it at low temperature to obtain a silicon-boron-zirconium-containing resin solution;

[0046] S4) adding hexamethylenetetramine to the silicon-boron-zirconium resin solution and dissolving it at low temperature to obtain a curable reaction solution;

[0047] S5) placing the curable reaction solution in a sealed container and curing it at low temperature to obtain a silicon-boron-zirconium modified phenolic resin wet gel;

[0048] S6) gradient drying the boron-silicon-zirconium modified phenolic resin wet gel to obtain boron-silicon-zirconium modified phenolic resin aerogel.

[0049] Specifically, the curing temperature of the curable reaction liquid is 60-90°C, and the curing time is 20-50h;

[0050] The low temperature dissolution temperature of thermoplastic phenolic resin and boron phenolic resin is 40-50℃;

[0051] The low-temperature dissolution temperature of phenolic resin solution and silicone resin is 40-50°C.

[0052] Specifically, the mass ratio of the thermoplastic phenolic resin to the organic solvent is 1:(1.2-4); the mass ratio of the thermoplastic phenolic resin to the boron phenolic resin is 1:(0.1-0.3).

[0053] Specifically, the mass ratio of the silicone resin to the thermoplastic phenolic resin is (0.1-0.25):1.

[0054] Specifically, the mass ratio of the zirconium source to the silicone resin is (0.2-0.6):1.

[0055] Specifically, the mass ratio of hexamethylenetetramine to thermoplastic phenolic resin is (0.14-0.25):1.

[0056] Specifically, the molecular weight of the boron phenolic resin is 3000-5000, and the boron content is 2%-10%.

[0057] Specifically, the molecular weight of the thermoplastic phenolic resin is 3000-5000;

[0058] The molecular weight of silicone resin is 1000-2500, and its active functional group is silicon-oxygen bond;

[0059] The gradient drying of the silicon-modified phenolic wet gel is divided into two temperature gradients, the first temperature gradient is 20-40°C, the second temperature gradient is 70-90°C, and the drying time of each gradient is 24h;

[0060] The pH adjusting liquid is an acidic adjusting liquid or an alkaline adjusting liquid.

[0061] Specifically, the organic solvent is one of anhydrous ethanol, ethylene glycol or isopropanol; the zirconium source is one of zirconium nitrate, zirconium sulfate and zirconium oxychloride.

[0062] The present invention also provides a silicon-boron-zirconium modified phenolic aerogel obtained based on the method for preparing the thermal insulation and ablation-resistant integrated aerogel as described in any one of the above.

[0063] The invention provides a method for preparing a thermally insulating and ablation-resistant integrated aerogel, wherein three materials, namely, a boron phenolic resin, an organic silicon resin and an inorganic zirconium source, are introduced; the solidified boron phenolic resin and the main phenolic resin form a physical entanglement, thereby improving the ablation resistance of the aerogel; the organic silicon resin and the main phenolic resin are tightly combined in the form of chemical bonds, thereby greatly improving the thermal insulation capacity of the aerogel; and the inorganic zirconium source is doped into the boron silicon-modified organic skeleton, thereby further improving the thermal insulation and ablation resistance of the aerogel, thereby making it possible to apply the aerogel to thermal insulation and ablation components in aerospace vehicles.

[0064] The method for preparing the thermally insulating and ablation-resistant integrated aerogel provided by the present invention can achieve consistency in the curing rates of different components by setting the raw material ratio and curing conditions, thereby reducing the final curing temperature to below 90° C., does not involve high-temperature and high-pressure reactions, and reduces the requirements for production equipment.

[0065] During the implementation of the present invention, less or no highly toxic gas is volatilized, and the impact on the health of operators is relatively small.

[0066] Embodiment 1

[0067] A method for preparing a heat-insulating and ablation-resistant integrated aerogel comprises the following steps:

[0068] 101) adding 20 g of thermoplastic phenolic resin and 4 g of boron phenolic resin into a sealable glass bottle, pouring 50 g of anhydrous ethanol into the sealable glass bottle, stirring and dissolving at 50° C. to obtain a phenolic resin solution;

[0069] 102) Add 5 g of organosilicon resin and 0.75 mL of aqueous ammonia to the phenolic resin solution, and stir at 40° C. for 4 h to obtain a silicon-boron-containing resin solution, wherein the aqueous ammonia concentration is 1 mol / L;

[0070] 103) adding 3 g of zirconium oxychloride to the silicon-boron-containing resin solution and dissolving it at 40° C. to obtain a silicon-boron-zirconium-containing resin solution;

[0071] 104) adding 5 g of hexamethylenetetramine to the silicon-boron-zirconium resin solution, stirring and dissolving at 40° C. to obtain a curable reaction solution;

[0072] 105) placing the curable reaction solution in a sealed container, curing at 70° C. for 48 hours to obtain a boron-silicon-zirconium-modified phenolic resin wet gel;

[0073] 106) The silicon boron zirconium modified phenolic resin wet gel was subjected to gradient drying treatment, the first temperature gradient was room temperature, the second temperature gradient was 80°C, and the drying time of each gradient was 24h to obtain silicon boron zirconium modified phenolic resin aerogel with a density of 0.39g / cm 3 , thermal conductivity is 0.0978W / (m·k).

[0074] The molecular weight of the boron phenolic resin in this embodiment is 3000-5000, and the boron content is 2%-10%.

[0075] The molecular weight of the thermoplastic phenolic resin in this embodiment is 3000-5000.

[0076] The molecular weight of silicone resin is 1000-2500, and its active functional group is silicon-oxygen bond.

[0077] Figure 1This is a physical picture of the heat-insulating and ablation-resistant integrated gas condensate obtained in this embodiment. Figure 2 , Figure 3 This is a scanning electron microscope image of the heat-insulating and ablation-resistant integrated gas condensation obtained in this embodiment. Figure 4 The thermogravimetric diagram of the thermal insulation and ablation-resistant integrated gas condensation obtained in this embodiment is shown in FIG. Figures 1 to 4 It can be seen that the aerogel has a good appearance, fine and uniform pore size, and an oxygen-free residual weight of 58% at 800°C.

[0078] Embodiment 2

[0079] A method for preparing a heat-insulating and ablation-resistant integrated aerogel comprises the following steps:

[0080] 201) adding 25 g of thermoplastic phenolic resin and 3 g of boron phenolic resin into a sealable glass bottle, pouring 30 g of isopropyl alcohol into the sealable glass bottle, stirring and dissolving at 50° C. to obtain a phenolic resin solution;

[0081] 202) Add 4 g of silicone resin and 0.6 mL of acetic acid to the phenolic resin solution, and stir at 40° C. for 4 h to obtain a silicon-boron-containing resin solution, wherein the acetic acid concentration is 0.5 mol / L;

[0082] 203) adding 2 g of zirconium nitrate to the borosilicate resin solution and dissolving it at 40° C. to obtain a borosilicate zirconium resin solution;

[0083] 204) adding 5.8 g of hexamethylenetetramine to the silicon-boron-zirconium resin solution, stirring and dissolving at 40° C. to obtain a curable reaction solution;

[0084] 205) placing the curable reaction solution in a sealed container, curing at 80° C. for 36 hours to obtain a boron-silicon-zirconium-modified phenolic resin wet gel;

[0085] 206) Silicon boron zirconium modified phenolic resin wet gel gradient drying treatment, the first temperature gradient is room temperature, the second temperature gradient is 70 ° C, the drying time of each gradient is 24h, and silicon boron zirconium modified phenolic resin aerogel is obtained, and the aerogel density is 0.42g / cm 3 , thermal conductivity is 0.1042W / (m·k).

[0086] The molecular weight of the boron phenolic resin in this embodiment is 3000-5000, and the boron content is 2%-10%.

[0087] The molecular weight of the thermoplastic phenolic resin in this embodiment is 3000-5000.

[0088] The molecular weight of silicone resin is 1000-2500, and its active functional group is silicon-oxygen bond.

[0089] Figure 5This is a physical picture of the heat-insulating and ablation-resistant integrated gas condensate obtained in this embodiment. Figure 6 , Figure 7 This is a scanning electron microscope image of the heat-insulating and ablation-resistant integrated gas condensation obtained in this embodiment. Figure 8 The thermogravimetric diagram of the thermal insulation and ablation-resistant integrated gas condensation obtained in this embodiment is shown in FIG. Figures 5 to 8 It can be seen that the aerogel has a good appearance, fine and uniform pore size, and the oxygen-free residual weight at 800°C is 60%.

[0090] Embodiment 3

[0091] A method for preparing a heat-insulating and ablation-resistant integrated aerogel comprises the following steps:

[0092] 301) adding 20 g of thermoplastic phenolic resin and 2 g of boron phenolic resin into a sealable glass bottle, pouring 80 g of anhydrous ethanol into the sealable glass bottle, stirring and dissolving at 50° C. to obtain a phenolic resin solution;

[0093] 302) Add 4 g of organosilicon resin and 0.35 mL of boric acid to the phenolic resin solution, and stir at 40° C. for 1 h to obtain a silicon-boron-containing resin solution, wherein the boric acid concentration is 1 mol / L;

[0094] 303) adding 2 g of zirconium nitrate to the silicon-boron-containing resin solution and dissolving it at 40° C. to obtain a silicon-boron-zirconium-containing resin solution;

[0095] 304) adding 4.5 g of hexamethylenetetramine to the silicon-boron-zirconium resin solution, stirring and dissolving at 40° C. to obtain a curable reaction solution;

[0096] 305) placing the curable reaction solution in a sealed container, curing at 70° C. for 48 h to obtain a boron-silicon-zirconium-modified phenolic resin wet gel;

[0097] 306) Silicon boron zirconium modified phenolic resin wet gel gradient drying treatment, the first temperature gradient is 40 ° C, the second temperature gradient is 70 ° C, the drying time of each gradient is 24 h, and the silicon boron zirconium modified phenolic resin aerogel is obtained, with a density of 0.23 g / cm 3 , thermal conductivity is 0.0322W / (m·k), and the residual weight at 800℃ and nitrogen is 59%.

[0098] The molecular weight of the boron phenolic resin in this embodiment is 3000-5000, and the boron content is 2%-10%.

[0099] The molecular weight of the thermoplastic phenolic resin in this embodiment is 3000-5000.

[0100] The molecular weight of silicone resin is 1000-2500, and its active functional group is silicon-oxygen bond.

[0101] Embodiment 4

[0102] A method for preparing a heat-insulating and ablation-resistant integrated aerogel comprises the following steps:

[0103] 401) adding 30 g of thermoplastic phenolic resin and 9 g of boron phenolic resin into a sealable glass bottle, pouring 70 g of anhydrous ethanol into the sealable glass bottle, stirring and dissolving at 40° C. to obtain a phenolic resin solution;

[0104] 402) adding 6.5 g of organosilicon resin and 0.3 mL of dilute hydrochloric acid to the phenolic resin solution, stirring at 50° C. for 4 h to obtain a silicon-boron-containing resin solution, wherein the concentration of the dilute hydrochloric acid is 1 mol / L;

[0105] 403) adding 1.5 g of zirconium oxychloride to the silicon-boron-containing resin solution and dissolving it at 40° C. to obtain a silicon-boron-zirconium-containing resin solution;

[0106] 404) adding 6 g of hexamethylenetetramine to the silicon-boron-zirconium resin solution, stirring and dissolving at 40° C. to obtain a curable reaction solution;

[0107] 405) placing the curable reaction solution in a sealed container, curing at 90° C. for 42 hours to obtain a boron-silicon-zirconium-modified phenolic resin wet gel;

[0108] 406) Silicon boron zirconium modified phenolic resin wet gel gradient drying treatment, the first temperature gradient is 30 ° C, the second temperature gradient is 90 ° C, the drying time of each gradient is 24 h, and the silicon boron zirconium modified phenolic resin aerogel is obtained, with a density of 0.32 g / cm 3 , thermal conductivity is 0.0435W / (m·k), and the residual weight at 800℃ and nitrogen is 64%.

[0109] The molecular weight of the boron phenolic resin in this embodiment is 3000-5000, and the boron content is 2%-10%.

[0110] The molecular weight of the thermoplastic phenolic resin in this embodiment is 3000-5000.

[0111] The molecular weight of silicone resin is 1000-2500, and its active functional group is silicon-oxygen bond.

[0112] Embodiment 5

[0113] A method for preparing a heat-insulating and ablation-resistant integrated aerogel comprises the following steps:

[0114] 501) adding 15 g of thermoplastic phenolic resin and 3 g of boron phenolic resin into a sealable glass bottle, pouring 40 g of anhydrous ethanol into the sealable glass bottle, stirring and dissolving at 50° C. to obtain a phenolic resin solution;

[0115] 502) adding 2 g of organosilicon resin and 0.43 mL of acetic acid to the phenolic resin solution, stirring at 40° C. for 2 h, to obtain a silicon-boron-containing resin solution, wherein the acetic acid concentration is 1 mol / L;

[0116] 503) adding 1 g of zirconium nitrate to the borosilicate resin solution and dissolving it at 40° C. to obtain a borosilicate zirconium resin solution;

[0117] 504) adding 3 g of hexamethylenetetramine to the silicon-boron-zirconium resin solution, stirring and dissolving at 40° C. to obtain a curable reaction solution;

[0118] 505) placing the curable reaction solution in a sealed container, curing at 70° C. for 45 h to obtain a boron-silicon-zirconium-modified phenolic resin wet gel;

[0119] 506) The silicon boron zirconium modified phenolic resin wet gel was subjected to gradient drying treatment, the first temperature gradient was room temperature, the second temperature gradient was 70°C, and the drying time of each gradient was 24h to obtain silicon boron zirconium modified phenolic resin aerogel with a density of 0.30g / cm 3 The thermal conductivity is 0.0367W / (m·k), and the residual weight at 800℃ and nitrogen is 63%.

[0120] The molecular weight of the boron phenolic resin in this embodiment is 3000-5000, and the boron content is 2%-10%.

[0121] The molecular weight of the thermoplastic phenolic resin in this embodiment is 3000-5000.

[0122] The molecular weight of silicone resin is 1000-2500, and its active functional group is silicon-oxygen bond.

[0123] Embodiment 6

[0124] A method for preparing a heat-insulating and ablation-resistant integrated aerogel comprises the following steps:

[0125] 601) adding 15 g of thermoplastic phenolic resin and 3 g of boron phenolic resin into a sealable glass bottle, pouring 50 g of ethylene glycol into the sealable glass bottle, stirring and dissolving at 50° C. to obtain a phenolic resin solution;

[0126] 602) Add 3 g of organosilicon resin and 0.5 mL of aqueous ammonia to the phenolic resin solution, and stir at 40° C. for 1 h to obtain a silicon-boron-containing resin solution, wherein the aqueous ammonia concentration is 1 mol / L;

[0127] 603) adding 1.5 g of zirconium nitrate to the borosilicate resin solution and dissolving it at 40° C. to obtain a borosilicate zirconium resin solution;

[0128] 604) adding 2.1 g of hexamethylenetetramine to the silicon-boron-zirconium resin solution, stirring and dissolving at 40° C. to obtain a curable reaction solution;

[0129] 605) placing the curable reaction solution in a sealed container, curing at 85° C. for 30 h to obtain a boron-silicon-zirconium-modified phenolic resin wet gel;

[0130] 606) The silicon boron zirconium modified phenolic resin wet gel was subjected to gradient drying treatment to a constant weight, the first temperature gradient was 24°C, the second temperature gradient was 70°C, and the drying time of each gradient was 24h to obtain silicon boron zirconium modified phenolic resin aerogel with a density of 0.29g / cm 3 The thermal conductivity is 0.0314W / (m·k), and the residual weight at 800℃ and nitrogen is 64%.

[0131] The molecular weight of the boron phenolic resin in this embodiment is 3000-5000, and the boron content is 2%-10%.

[0132] The molecular weight of the thermoplastic phenolic resin in this embodiment is 3000-5000.

[0133] The molecular weight of silicone resin is 1000-2500, and its active functional group is silicon-oxygen bond.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a heat-insulating and ablation-resistant integrated aerogel, characterized in that: The steps include: Thermoplastic phenolic resin and boron phenolic resin are added into an organic solvent and dissolved at low temperature to obtain a phenolic resin solution; Adding organic silicon resin and pH adjusting liquid to the phenolic resin solution, dissolving at low temperature, and obtaining a silicon-boron containing resin solution; Adding a zirconium source to a silicon-boron-containing resin solution and dissolving it at low temperature to obtain a silicon-boron-zirconium-containing resin solution; Adding hexamethylenetetramine to the silicon-boron-zirconium resin solution and dissolving it at low temperature to obtain a curable reaction solution; The curable reaction liquid is placed in a sealed container and cured at low temperature to obtain a silicon-boron-zirconium modified phenolic resin wet gel; The silicon boron zirconium modified phenolic resin wet gel is subjected to gradient drying to obtain silicon boron zirconium modified phenolic resin aerogel.

2. The method for preparing the thermal insulation and ablation-resistant integrated aerogel according to claim 1, characterized in that: The curing temperature of the curable reaction liquid is 60-90°C, and the curing time is 20-50h; The low temperature dissolution temperature of thermoplastic phenolic resin and boron phenolic resin is 40-50℃; The low-temperature dissolution temperature of phenolic resin solution and silicone resin is 40-50°C.

3. The method for preparing the thermal insulation and ablation-resistant integrated aerogel according to claim 1, characterized in that: The mass ratio of the thermoplastic phenolic resin to the organic solvent is 1:(1.2-4); the mass ratio of the thermoplastic phenolic resin to the boron phenolic resin is 1:(0.1-0.3).

4. The method for preparing the thermal insulation and ablation-resistant integrated aerogel according to claim 1, characterized in that: The mass ratio of the silicone resin to the thermoplastic phenolic resin is (0.1-0.25):

1.

5. The method for preparing the thermal insulation and ablation-resistant integrated aerogel according to claim 1, characterized in that: The mass ratio of the zirconium source to the silicone resin is (0.2-0.6):

1.

6. The method for preparing the thermal insulation and ablation-resistant integrated aerogel according to claim 1, characterized in that: The mass ratio of hexamethylenetetramine to thermoplastic phenolic resin is (0.14-0.25):

1.

7. The method for preparing the thermal insulation and ablation-resistant integrated aerogel according to claim 1, characterized in that: The molecular weight of the boron phenolic resin is 3000-5000, and the boron content is 2%-10%.

8. The method for preparing thermal insulation and ablation-resistant integrated aerogel according to claim 1, characterized in that: The molecular weight of thermoplastic phenolic resin is 3000-5000; The molecular weight of silicone resin is 1000-2500, and its active functional group is silicon-oxygen bond; The gradient drying of the silicon-modified phenolic wet gel is divided into two temperature gradients, the first temperature gradient is 20-40°C, the second temperature gradient is 70-90°C, and the drying time of each gradient is 24h; The pH adjusting liquid is an acidic adjusting liquid or an alkaline adjusting liquid.

9. The method for preparing thermal insulation and ablation-resistant integrated aerogel according to claim 1, characterized in that: The organic solvent is one of anhydrous ethanol, ethylene glycol or isopropanol; the zirconium source is one of zirconium nitrate, zirconium sulfate and zirconium oxychloride.

10. A silicon-boron-zirconium modified phenolic aerogel obtained based on the method for preparing a thermally insulating and ablation-resistant integrated aerogel according to any one of claims 1 to 9.

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