Pyrolysis ablation heat shield matrix resin and method of making and use thereof

Abstract

The application provides a pyrolysis slow-release ablative heat protection matrix resin and a preparation method and use thereof, and belongs to the field of advanced polymer materials. In view of the contradiction between the high residual weight and the mass injection effect of the resin-based ablative heat protection material, the ferrocene-carborane synergistically modified phenolic resin with the pyrolysis slow-release characteristic is designed and prepared based on the ceramicization and catalytic oxidation strategy. The resin has excellent stability and a high mass residual rate in a high-temperature oxidation environment and can continuously release small-molecule pyrolysis gas in a wide temperature range. These characteristics enable the matrix resin to realize long-time gasification and mass injection with low mass loss in the ablative process, continuously play the ablative heat protection role, and effectively reduce the ablative back temperature. The application has important application prospects in the fields of high-speed vehicle heat protection such as long-time flight, super-long range and near space.

Description

Technical Field

[0001] This invention belongs to the field of advanced polymer materials, specifically relating to a pyrolysis-controlled release ablation heat protection matrix resin, its preparation method, and its uses. Background Technology

[0002] High-speed, long-range aircraft face the threat of harsh aerodynamic heating environments over extended periods, making thermal protection materials a crucial component for ensuring the successful completion of flight missions. Ablation-resistant thermal protection materials can achieve cooling and drag reduction through thermal blocking effects and the fluid boundary layer formed by pyrolysis gases, thereby ensuring the safe operation of the aircraft. Phenolic resins, due to their aromatic structure, possess excellent thermal stability and char-forming properties, making them widely used in the thermal protection systems of aerospace vehicles. However, phenolic resins have poor oxidation resistance and undergo vigorous pyrolysis, resulting in short thermal blocking effects and boundary layer maintenance times, and the formed char layer is loose and porous. These drawbacks make unmodified phenolic resins unsuitable for meeting the thermal protection requirements of next-generation aerospace vehicles in the prolonged high-heat-flux environment of near-space.

[0003] To further improve the ablation thermal protection performance of phenolic resins under high-temperature oxidizing environments, existing research has largely focused on "ceramization" or "carbonization / graphitization." This involves modifying phenolic resins with ceramicizing elements such as silicon, boron, zirconium, hafnium, and titanium, or transition metal elements that promote graphitization such as cobalt and nickel. The aim is to reduce mass loss during pyrolysis / ablation, thereby extending their service life in harsh environments. However, these studies neglect the core mechanism of ablation thermal protection—"mass ejection-thermal blocking"—and the ultimate goal of ablation thermal protection—"reducing ablation back temperature." Simply pursuing reduced mass loss during pyrolysis / ablation can, to some extent, enhance durability in harsh environments, but low mass projection leads to a thin boundary layer and insufficient thermal protection efficiency. For example, the literature (DOI:10.1016 / j.polymdegradstab.2025.111335) significantly improved the thermo-oxidative stability of phenolic resin by constructing a carborane hybrid crosslinking network. The mass loss (MAR) of the prepared hybrid resin (CBPR) during ablation was reduced, but the back temperature of ablation remained relatively high. On the other hand, simply pursuing the release of pyrolysis gas not only weakens the durability of the material, but the rapidly decaying ablation interface and the porous structure generated by the large release of gas also weaken the insulation ability of the carbon layer against high temperatures, which is also not conducive to reducing the ablation back temperature. In addition, the pyrolysis products of boron, silicon, and other ceramic-modified phenolic resins contain a large number of alkanes and aromatic hydrocarbons. These substances have a large molar mass and a limited gas volume per unit mass, which reduces the thermal blocking efficiency of the ablation heat protection material.

[0004] How to continuously release sufficient gas (CO2, H2O, etc.) to form a stable gas boundary layer while minimizing mass loss is key to improving the long-term thermal protection performance of thermal protection materials. Related research indicates that ferrocene and its derivatives possess the ability to catalyze the oxidative degradation of hydrocarbons and have been widely applied in areas such as motor vehicle exhaust and industrial waste gas treatment. Introducing ferrocene into a carborane-phenol-aldehyde crosslinking network, and utilizing ferrocene catalytic oxidation to further decompose large molecular hydrocarbons into smaller molecular gases while reducing mass loss through ceramization, can significantly increase the volume expansion ratio while reducing mass loss, giving the material both "low ablation rate and high back-temperature suppression."

[0005] Therefore, for long-term aerobic operating environments, and considering the problems of limited pyrolysis gas volume per unit mass, low gas blockage efficiency, short thermal protection time, and insufficient efficiency of existing ceramic-modified phenolic resins, it is essential to develop a new type of phenolic resin that combines high char residue, low back temperature, and controllable slow gas release characteristics, based on carborane hybrid modification and utilizing the catalytic effect of ferrocene on the decomposition of hydrocarbon compounds. This is crucial to ensure the safe operation of high-value aerospace vehicles in the near-space environment with long durations and high heat flux. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, the purpose of this invention is to provide a pyrolysis-controlled release ablation heat protection matrix resin, its preparation method and uses.

[0007] This invention provides a pyrolysis-controlled release ablation heat protection matrix resin, wherein the structure of the pyrolysis-controlled release ablation heat protection matrix resin includes the structural segment shown in Formula I:

[0008]

[0009] Furthermore, it is prepared using borane-phenol copolymer, ferrocene oligomer and phenolic resin as raw materials; wherein the mass ratio of borane-phenol copolymer, ferrocene oligomer and phenolic resin is 20:1 to 40:40 to 80.

[0010] Furthermore, the structure of the borane-phenol copolymer is shown in Formula II:

[0011]

[0012] The ratio of m to n is 1-3:1-4;

[0013] Furthermore, the ratio of m to n is 1:1.25;

[0014] The structure of the ferrocene oligomer is shown in Formula III:

[0015]

[0016] Furthermore, the preparation method of the borane-phenol copolymer includes the following steps: reacting carboranephenol, phenolic compounds, aldehyde compounds and a catalyst to obtain the borane-phenol copolymer.

[0017] Further, the mass ratio of the carborane phenol, phenolic compound, aldehyde compound and catalyst is 5-15:3-7:10-20:0.1-0.3; the phenolic compound is selected from phenol or its homologues, hydroquinone or its homologues, preferably phenol; the aldehyde compound is selected from formaldehyde, acetaldehyde, furfural, or paraformaldehyde, preferably formaldehyde; the catalyst is selected from alkali, alkali metal, alkaline earth metal hydroxide, carbonate, alkoxide or ammonia.

[0018] Furthermore, the catalyst is selected from triethylamine, ethylenediamine, potassium hydroxide, barium hydroxide, potassium carbonate, sodium carbonate, sodium ethoxide, potassium tert-butoxide, or ammonia, preferably sodium hydroxide.

[0019] Furthermore, the mass ratio of the carboranephenol, phenolic compound, aldehyde compound and catalyst is 10:1 to 10:5 to 25:0.2;

[0020] The solvent for the reaction is one or a mixture of several of the following: alcohols (methanol, ethanol, isopropanol, n-propanol, n-butanol, etc.), ketones (acetone, butanone, methyl ethyl ketone, etc.), ethers (ethylene glycol monomethyl ether, tetrahydrofuran, dioxane, etc.), and aromatic hydrocarbons (toluene, xylene, etc.), preferably isopropanol; the reaction temperature is 80–90°C, preferably 85°C; and the reaction time is 6–10 h, preferably 8 h.

[0021] Furthermore, the method for preparing the carboranephenol includes the following steps:

[0022] Carboranephenol precursor reacts with a demethylating agent to yield carboranephenol; wherein the molar ratio of carboranephenol precursor to demethylating agent is 1:3 to 12;

[0023]

[0024] R1 is selected from hydrogen and C. 1～5 Alkyl, C 2～5 alkenyl, C 1～5 Alkoxy, unsubstituted or R a Substituted 5- to 6-membered aryl groups;

[0025] R2 is selected from hydroxyl protecting groups, silyl protecting groups, ether protecting groups, silyl ether protecting groups, or ester protecting groups; R2 is selected from -LR. b -COR d Not replaced or R c The following groups are substituted: C1～5 Alkyl, silicon-based;

[0026] R3 is selected from hydrogen, C 1～5 Alkyl, C 2～5 alkenyl, C 1～5 Alkoxy, unsubstituted or R a Substituted 5- to 6-membered aryl groups;

[0027] R a Selected independently from C 1～5 Alkoxy;

[0028] R c Independently selected from 5-6 aryl, C 1～5 Alkyl, C 1～5 Alkoxy, -LR b ;

[0029] L is selected from C 1～5 Alkylene, C 1～5 Alkoxy;

[0030] R b Independently selected from unsubstituted or R a Substituted 5- to 6-membered aryl groups;

[0031] R d Selected independently from C 1～5 Alkyl, 5-6 aryl, halogen-substituted C 1～5 alkyl.

[0032] Furthermore, the method for preparing the carboranephenol includes the following steps:

[0033]

[0034] Further, the demethylating agent is boron trichloride, boron tribromide, hydrobromic acid, hydroiodic acid, boron trifluoride diethyl ether, aluminum trichloride, ferric chloride, boron trifluoride, pyridine hydrochloride, or p-toluenesulfonic acid, preferably boron tribromide.

[0035] Furthermore, the preparation method of the carboranephenol precursor includes the following steps:

[0036]

[0037] Furthermore, the preparation method of the 4-methoxycarboborane includes the following steps:

[0038]

[0039] Furthermore, the preparation method of the decaboron-dodecyl diacetonitrile complex includes the following steps:

[0040]

[0041] Furthermore, the preparation method of the ferrocene oligomer includes the following steps: reacting phenol, ferrocene formaldehyde, and a catalyst, and then adding terephthalaldehyde to continue the reaction, thereby obtaining the ferrocene oligomer.

[0042] Furthermore, the mass ratio of phenol, ferrocene formaldehyde, terephthalaldehyde and catalyst is 10-25:1-4:5-15:0.2.

[0043] Furthermore, the mass ratio of phenol, ferrocene formaldehyde, terephthalaldehyde, and catalyst is 23.5:2.67:13.4:0.2;

[0044] The solvent for the reaction is an organic solvent, preferably ethanol; the reaction temperature is 120–140°C, preferably 130°C; the reaction time is 1–3 h, preferably 2 h; the temperature for the continued reaction is 80–120°C, preferably 100°C; the reaction time is 4–8 h, preferably 6 h.

[0045] The present invention also provides a method for preparing the above-mentioned pyrolysis-controlled release ablation heat protection matrix resin, the method comprising the following steps: mixing and reacting borane-phenol copolymer, ferrocene oligomer and phenolic resin, heating, pulverizing and curing, to obtain the resin.

[0046] Furthermore, the solvent for the reaction is an organic solvent; the heating temperature is 90–130°C, and the time is 1–3 h; the curing conditions are: heating at a pressure of 3–7 MPa with a temperature gradient of 100–200°C for 0.2–3 h.

[0047] Furthermore, the solvent for the reaction is ethanol; the heating temperature is 110℃ for 2 hours; the pressure is 5 MPa; and the gradient heating conditions are: 110℃ / 30 min, 130℃ / 30 min, 160℃ / 2 hours, and 180℃ / 2 hours.

[0048] This invention also provides the use of the above-mentioned pyrolysis-controlled ablation heat protection matrix resin in the preparation of heat protection coatings for long-endurance, ultra-long-range, near-space high-speed aircraft, aerospace reciprocating aircraft, high-temperature heat protection composite materials, and high-temperature resistant sealant adhesives.

[0049] The present invention has achieved the following beneficial effects:

[0050] (1) In this invention, phenolic resin modified with ferrocene and carborane is used to prepare a pyrolysis slow-release ablation heat protection matrix resin to address the contradiction between high residual weight of anti-oxidation and thermal blockage effect of pyrolysis gas. This resin can achieve a lower ablation back temperature with lower mass loss.

[0051] (2) The CBPR prepared in the literature (DOI:10.1016 / j.polymdegradstab.2025.111335) was tested for its mass ablation rate and at 800℃ using an oxyacetylene ablation apparatus (ZR-323A, Xi'an Zhirui Company). 800℃ The residual weight below ) is used to compare CBPR 0.2 The differences between the hybrid phenolic resin and the present invention were simultaneously tested using an oxyacetylene ablation apparatus (Beijing Qinhe Technology Co., Ltd.). The results showed that, under the same testing conditions and equipment, the CBPR-Fe prepared by the present invention... 1‰ While maintaining a constant back temperature (75°C), a higher residual carbon ratio (R) was obtained. 800℃ The yield was 61.21%, achieving unexpected technical results. This invention's pyrolysis-controlled release ablation thermal protection matrix resin has broad application prospects in the thermal protection of long-endurance, ultra-long-range, near-space high-speed aircraft and aerospace vehicles.

[0052] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0053] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following embodiments. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0054] Figure 1 (a) Schematic diagram of the hybrid phenolic resin structure of the present invention; (b) Infrared spectrum of ferrocene oligomer (FePR); (c) 1H NMR spectrum of FePR; (d) Different hybrid phenolic resins (CBPR-Fe 0.5‰ CBPR-Fe 1‰ CBPR-Fe 2‰ CBPR-Fe 4‰ CBPR-Fe 6‰ (e) Infrared spectrum; (f) XPS energy dispersive spectroscopy; (g) Scanning electron microscope image.

[0055] Figure 2 For different hybrid phenolic resins (CBPR-Fe) 0.5‰ CBPR-Fe 1‰ CBPR-Fe 2‰ CBPR-Fe 4‰ CBPR-Fe 6‰(a) Thermogravimetric analysis (TGA) curves and (b) Differential thermogravimetric analysis (DTG) curves under air atmosphere, and at 4 MW / m 2 (c) Mass ablation rate (MAR) and (d) Linear ablation rate (LAR) after 30 s of oxyacetylene flame ablation.

[0056] Figure 3 Infrared spectra of pyrolysis gases in air atmosphere: (a) Hybrid phenolic resin (CBPR-Fe) 1‰ (b)PR; (c)CBPR 0.2 .

[0057] Figure 4 For different hybrid phenolic resins (CBPR-Fe) 05‰ CBPR-Fe 1‰ CBPR-Fe 2‰ CBPR-Fe 4‰ CBPR-Fe 6‰ The back temperature results are shown in the figure. Detailed Implementation

[0058] The raw materials and equipment used in this invention are all known products, obtained by purchasing commercially available products.

[0059] In this invention, "room temperature" means 25±10℃.

[0060] Example 1: Preparation of Hybrid Phenolic Resin

[0061] 1. Preparation of decaboron-dodecyl diacetonitrile complex (CB)

[0062] Decaborane was dissolved in anhydrous acetonitrile and heated under an anhydrous and oxygen-free environment for a period of time. After the reaction was completed, the mixture was cooled for a period of time to obtain a white powdery product with the molecular formula B. 10 H 12 (CH3CN)2, abbreviated as CB.

[0063] 2. Preparation of 4-methoxycarboborane (CBE)

[0064] In an anhydrous and oxygen-free environment, 4-ethynyl anisole and B... 10 H 12 The addition reaction of (CH3CN)2 yields 4-methoxycarboborane, abbreviated as CBE.

[0065] 3. Preparation of carboranephenol (CBP)

[0066] The methyl group in CBE was removed using BBr3 to obtain carborane phenol (CBP).

[0067] 4. Preparation of Borane-Phenol Copolymer (CB-co-Ph)

[0068] Allyl carborophenolic resin (CB-co-Ph) was prepared by heating and reacting carborophenol, other phenolic compounds, and aldehydes under alkaline catalysis for a period of time.

[0069] 5. Preparation of ferrocene oligomers (FePR)

[0070] Phenol (Ph, 23.5 g), ferrocene formaldehyde (Cp-Fe, 2.67 g), and sodium hydroxide (NaOH, 0.2 g) were added to a three-necked flask containing ethanol (10 mL). The mixture was reacted at 130 °C for 2 hours. Subsequently, the reaction system was cooled to 100 °C. At this point, terephthalaldehyde (TPAL, 13.4 g) was added, and the reaction was stirred for another 6 hours to obtain ferrocene oligomer (FePR). During this process, the color of the reaction mixture gradually changed from reddish-brown to purplish-black.

[0071] 6. Preparation and curing of hybrid phenolic resins

[0072] According to the material formulation in Table 1, 20 wt% of carbon boron-phenol copolymer, 3 wt% of ferrocene oligomer, and 77 wt% of phenolic resin were dissolved in ethanol and mixed evenly. The viscous liquid obtained by rotary evaporation was further prepolymerized in a vacuum oven at 110°C for 2 hours to obtain a semi-cured block resin. The block resin was pulverized into powder using a pulverizer. The resin powder was filled into a steel mold and hot-pressed for curing with a gradient temperature increase (110°C / 30 min, 130°C / 30 min, 160°C / 2 h, 180°C / 2 h) (initial pressure 5 MPa). A hybrid phenolic resin (denoted as CBPR-Fe) was obtained. 05‰ ),like Figure 1 As shown in a.

[0073] Reference CBPR-Fe 0.5‰ The preparation method, according to the material formulation in Table 1, under the same experimental conditions, yielded different hybrid phenolic resins (denoted as CBPR-Fe). 1‰ CBPR-Fe 2‰ CBPR-Fe 4‰ CBPR-Fe 6‰ ).

[0074] Table 1. Composition of different groups of phenolic resins

[0075]

[0076]

[0077] The following is the method for preparing the control sample.

[0078] Comparative Example 1: Preparation of pure PR phenolic resin

[0079] Refer to CBPR-Fe 0.5‰ The preparation method is as follows: according to the material formulation in Table 1, under the same experimental conditions, pure PR phenolic resin (denoted as PR) was prepared using phenolic resin.

[0080] Comparative Example 2: Preparation of phenolic resin containing only carborane

[0081] Hydroxymethylated carborane segments (CBPF) were prepared according to the method described in the literature (DOI:10.1016 / j.polymdegradstab.2025.111335).

[0082] Refer to CBPR-Fe 0.5‰ The preparation method, according to the material formulation in Table 1, under the same experimental conditions, uses phenolic resin and CBPF to prepare a phenolic resin containing only carborane (denoted as CBPR). 0.2 ).

[0083] The following experimental examples demonstrate the beneficial effects of the present invention.

[0084] Experiment Example 1: Testing the performance of hybrid phenolic resins

[0085] 1. Experimental Methods

[0086] (1) Thermogravimetric analysis (TGA) curves were obtained using TG209F1 (Gertebau GmbH, Germany). All samples (5 mg) were heated from 50 °C to 800 °C at a heating rate of 10 °C / min.

[0087] (2) Thermogravimetric-infrared spectroscopy (TG-FTIR) was performed using a NETZSCH-STA 449F3+ThermoFisher-Nicoleti S50 simultaneous analyzer. All samples (5 mg) were heated from 25 °C to 1000 °C at a heating rate of 50 °C / min.

[0088] (3) Using an oxyacetylene ablation device (Beijing Qinhe Technology Co., Ltd.) at 4MW / m 2 Each sample underwent ablation performance testing for 30 seconds under a hot flux. Acetylene gas pressure was 0.095 MPa, flow rate 18.6 L / min; oxygen gas pressure was 0.4 MPa, flow rate 25.2 L / min; and the flame nozzle (inner diameter: ...) was used.

[0089] The distance between the 2.0mm and the sample surface is 10mm.

[0090] 2. Experimental Results

[0091] Figure 1The results from bg indicate that this invention successfully prepared different hybrid phenolic resins (CBPR-Fe). 0.5‰ CBPR-Fe 1‰ CBPR-Fe 2‰ CBPR-Fe 4‰ CBPR-Fe 6‰ Table 2. TGA, DTG, and 4MW / m³ performance of different hybrid phenolic resins in air atmosphere. 2 Mass ablation rate, linear ablation rate, and back temperature of oxyacetylene flame ablation for 30 s

[0092]

[0093]

[0094] Figure 2-4 The results in Table 2 show that, compared with pure PR, the thermal stability of the hybrid phenolic resin of this invention is improved at 4MW / m 2 The mass ablation rate under oxyacetylene flame ablation is significantly reduced, indicating a significant improvement in high-temperature ablation resistance and thermal protection performance. Lower back-temperature ablation can be achieved with lower mass loss.

[0095] And with CBPR 0.2 In comparison, the hybrid phenolic resin of this invention exhibits significantly increased thermal weight loss in air, indicating that the material of this invention has better carbonization efficiency at high temperatures and superior thermal stability. Specifically, the CBPR-Fe prepared by this invention... 1‰ While maintaining a constant back temperature, a higher residual carbon rate was achieved, resulting in unexpected technical effects.

[0096] In summary, this invention provides a pyrolysis-controlled release ablation thermal protection matrix resin, its preparation method, and its applications. Addressing the contradiction between high residual weight due to oxidation and the thermal blockage effect of pyrolysis gases, this invention designs and prepares a ferrocene and carborane-modified phenolic resin with pyrolysis-controlled release properties based on a ceramicization and catalytic oxidation strategy. This resin exhibits excellent stability and a high residual mass under high-temperature oxidation conditions and can continuously release small-molecule pyrolysis gases over a wide temperature range. These characteristics enable the resin to achieve a lower ablation back temperature with lower mass loss during the ablation process. This pyrolysis-controlled release ablation thermal protection matrix resin has broad application prospects in the thermal protection of high-speed aircraft such as long-endurance, ultra-long-range, and near-space vehicles.

Claims

1. A pyrolysis-controlled release ablation heat protection matrix resin, characterized in that, The structure of the pyrolytic slow-release ablation heat protection matrix resin includes the structural segment shown in Formula I: Formula I.

2. The pyrolysis-controlled release ablation heat protection matrix resin according to claim 1, characterized in that, It is prepared from boron-phenol copolymer, ferrocene oligomer and phenolic resin as raw materials; wherein the mass ratio of boron-phenol copolymer, ferrocene oligomer and phenolic resin is 20:1~40:40~80.

3. The pyrolysis-controlled release ablation heat protection matrix resin according to claim 2, characterized in that, The structure of the borane-phenol copolymer is shown in Formula II: Formula II The ratio of m to n is 1~3:1~4; The structure of the ferrocene oligomer is shown in Formula III: Formula III.

4. The pyrolysis-controlled release ablation heat protection matrix resin according to claim 3, characterized in that, The preparation method of the borane-phenol copolymer includes the following steps: reacting carboranephenol, phenolic compounds, aldehyde compounds and catalyst to obtain the borane-phenol copolymer.

5. The pyrolysis-controlled release ablation heat protection matrix resin according to claim 4, characterized in that, The mass ratio of the carborane phenol, phenolic compound, aldehyde compound and catalyst is 5~15:3~7:10~20:0.1~0.3; the phenolic compound is selected from phenol or its homologues, hydroquinone or its homologues; the aldehyde compound is selected from formaldehyde, acetaldehyde, furfural, or paraformaldehyde; the catalyst is selected from alkali, alkali metal, alkaline earth metal hydroxide, carbonate, alkoxide or ammonia.

6. The pyrolysis-controlled release ablation heat protection matrix resin according to claim 5, characterized in that, The phenolic compound is phenol; the aldehyde compound is formaldehyde.

7. The pyrolysis-controlled release ablation heat protection matrix resin according to claim 3, characterized in that, The preparation method of the ferrocene oligomer includes the following steps: reacting phenol, ferrocene formaldehyde and catalyst, and then adding terephthalaldehyde to continue the reaction to obtain the ferrocene oligomer.

8. The pyrolysis-controlled release ablation heat protection matrix resin according to claim 7, characterized in that, The mass ratio of phenol, ferrocene formaldehyde, terephthalaldehyde and catalyst is 10~25:1~4:5~15:0.

2.

9. A method for preparing the pyrolysis-controlled release ablation heat-protective matrix resin according to any one of claims 1 to 8, characterized in that, The method includes the following steps: mixing and reacting borane-phenol copolymer, ferrocene oligomer and phenolic resin, heating, pulverizing and curing to obtain the final product.

10. The method according to claim 9, characterized in that, The solvent used in the reaction is an organic solvent; the heating temperature is 90~130℃ and the time is 1~3h; the curing conditions are: heating at a pressure of 3~7 MPa with a temperature gradient of 100~200℃ for 0.2~3h.

11. The use of the pyrolysis-controlled ablation heat protection matrix resin according to any one of claims 1 to 8 in the preparation of heat protection coatings for long-endurance, ultra-long-range, near-space high-speed aircraft, aerospace reciprocating aircraft, high-temperature heat protection composite materials, and high-temperature resistant sealant adhesives.

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