Hafnium hybrid carbon-rich polysiloxane flexible ablative material as well as preparation method and application thereof

Abstract

The invention discloses a hafnium hybrid carbon-rich polysiloxane flexible ablation material as well as a preparation method and application thereof, and belongs to the field of advanced materials. According to the invention, a hafnium hybrid carbon-rich siloxane system is designed; in the ablation process, on one hand, a continuous stable carbon skeleton is constructed through a phenyl / vinyl carbon-rich structure; on the other hand, an Hf-O-Si structure is introduced into a polysiloxane main chain, so that formation of SiHfOC composite ceramic at high temperature is promoted, the ablation resistance of the flexible polysiloxane material is remarkably improved, and the flexible polysiloxane material can be used as a base material of a flexible thermal protection coating, a structural part and the like and has a very good application prospect in the field of thermal protection materials.

Description

Technical Field

[0001] The invention belongs to the field of advanced materials, and in particular relates to a hafnium hybrid carbon-rich polysiloxane flexible ablative material and a preparation method and application thereof. Background Art

[0002] Polysiloxane is a type of polymer material with both organic and inorganic hybrid properties. Its main molecular chain is composed of highly flexible and high-energy Si-O-Si bonds and connected to organic side groups. This material has excellent large deformation capacity, thermal stability, wide temperature range adaptability and good processability. In addition, polysiloxane can undergo organic-inorganic transformation in an ablative environment to generate high-temperature resistant materials such as silicon dioxide, silicon carbide, and amorphous SiOC, and has a wide range of applications in thermal protection fields such as heat insulation, flame retardancy, and ablation. In order to obtain high maneuverability and cross-domain high-speed flight capabilities, the structural design of aircraft is evolving towards a deformable direction, which puts higher requirements on the thermal protection system-the material needs to have comprehensive properties such as high temperature resistance, large deformation resistance, oxidation resistance and ablation resistance. Polysiloxane meets the dynamic thermal protection needs of new aircraft and has become an important candidate material for flexible ablative thermal protection of aerospace vehicles.

[0003] During the ablation process, polymer-based ablative materials will form a carbonized protective layer to isolate the substrate from the hot oxygen flame flow and thus reduce the ablation rate of the material. A dense and complete carbon layer is crucial to its ablation performance. However, the existing polysiloxane has a low carbon content, and the carbon-poor SiOC carbon layer formed at high temperature is easily oxidized and melted in a hot oxygen environment. At the same time, during the organic-inorganic transformation process, the volume shrinkage of the material will lead to loose bonding between carbonized particles, and the carbon layer is prone to structural collapse under the scouring of high-temperature airflow. Introducing ablation-resistant fillers (such as carbon fiber, carbon nanotubes, zirconium oxide, zirconium carbide, zirconium silicide, etc.) is a common method to improve the ablation resistance of polysiloxane. Ablation-resistant fillers can be used as "anchors" to strengthen the carbon layer and improve the ablation resistance of the material, but when the filling amount is high, there are often adverse effects such as difficulty in uniformly dispersing the filler in the material, increased density, and decreased flexibility. It is urgent to develop polysiloxane materials with excellent flexibility and ablation resistance and heat protection to meet the increasingly urgent demand for new high-performance flexible thermal protection materials.

[0004] Introducing heterogeneous elements and carbon-rich structures into the siloxane molecular structure can not only slow down the pyrolysis of the material by catalyzing graphitization to form a more stable and dense carbon layer and quenching free radicals during the pyrolysis of the material, but also generate high-temperature resistant composite ceramics during the ablation process to effectively improve the oxidation resistance, deformation resistance and density of the polysiloxane carbon layer without sacrificing the flexibility and high filling capacity of the material. It is an effective means to improve the ablation performance of the material.

[0005] At present, the reports on hafnium-containing polysiloxane are limited to the use of hafnium-containing polysiloxane as a ceramic precursor, and there are no related reports in the field of flexible ablation resistance. Zhang et al. (Zhang Liyan. Preparation and physical and chemical properties of HfC and HfC / SiC ceramic precursors [D]. Hunan: National University of Defense Technology, 2017.) used the precursor conversion method to prepare the HfC ceramic precursor polyhafnium carbosilane (PHCO) by constructing Hf-O bonds, and used this precursor as a raw material to blend with SiC ceramic precursor liquid polycarbosilane to prepare HfC / SiC composite ceramic precursor. The precursor synthesis process is simple, the process flow is short, the oxygen content of the ceramic product converted by pyrolysis is low, and the phase composition of HfC / SiC composite ceramic is controllable. Sun et al. (SUN JIA, WEN QING-BO, LI TAO, et al. Phase evolution of SiOC-based ceramic nanocomposites derived from apolymethylsiloxane modified by Hf- and Ti-alkoxides[J]. Journal of the American Ceramic Society, 2020, 103(2): 1436-1445. DOI: 10.1111 / jace.16817.) studied the phase evolution of SiOC-based ceramic nanocomposites derived from apolymethylsiloxane modified by Hf- and Ti-alkoxides (such as Hf(O n Bu) 4 and Hf(O i Pr) 4 ) was chemically modified to prepare a single source precursor (SSP), which was then pyrolyzed (1100-1300°C) to obtain SiOC / HfO 2 Nanocomposite materials. Summary of the invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides a hafnium hybrid carbon-rich polysiloxane flexible ablative material, which innovatively introduces hafnium into the carbon-rich polysiloxane system to achieve more excellent anti-ablation performance.

[0007] The hafnium hybrid carbon-rich polysiloxane of the present invention is obtained by curing a polysiloxane matrix; the polysiloxane matrix is ​​prepared by reacting phenyl-containing silane, alkenyl-containing silane, hafnium source and silane end-capping agent as raw materials; the molar ratio of the phenyl-containing silane, alkenyl-containing silane, hafnium source and silane end-capping agent is (0.1-20):(0.01-10):(0.005-5):(0.001-1).

[0008] Further, the hafnium source is hafnium dimethoxydiacetylacetonate, hafnium diethoxydiacetylacetonate, hafnium di-n-propoxydiacetylacetonate, hafnium diisopropoxydiacetylacetonate, hafnium tetramethoxy, hafnium tetraethoxy, hafnium tetra-n-propoxy, hafnium tetraisopropoxy, hafnium tetrachloride, hafnium oxychloride, hafnium hydroxide, hafnium dichloride or hafnium acetylacetonate;

[0009] The phenyl-containing silane is dimethoxymethylphenylsilane, dimethoxyethylphenylsilane, dimethoxydiphenylsilane, trimethoxyphenylsilane, diethoxymethylphenylsilane, diethoxyethylphenylsilane, diethoxydiphenylsilanesilane, triethoxyphenylsilane, dihydroxydiphenylsilane, diisopropoxymethylphenylsilane, diisopropoxyethylphenylsilane, diisopropoxydiphenylsilane, triisopropoxymethylphenylsilane, dichlorodiphenylsilane or dichloromethylphenylsilane;

[0010] The alkenyl-containing silane is dimethoxymethylvinylsilane, dimethoxyethylvinylsilane, trimethoxymethylvinylsilane, diethoxymethylvinylsilane, diethoxyethylvinylsilane, triethoxyvinylsilane, diisopropoxymethylvinylsilane, diisopropoxyethylvinylsilane, triisopropoxyvinylsilane, dichloromethylvinylsilane, dichloroethylvinylsilane, trichlorovinylsilane or hydroxyl-terminated vinyl silicone oil;

[0011] The silane end-capping agent is ethoxytrimethylsilane, methoxytrimethylsilane, isopropoxytrimethylsilane, chlorotrimethoxysilane, tetramethyldisiloxane, hexamethyldisiloxane or divinyltetramethyldisiloxane;

[0012] The molar ratio of the phenyl-containing silane, the alkenyl-containing silane, the hafnium source and the silane end-capping agent is (1-10):(0.1-5):(0.05-0.5):(0.01-0.1).

[0013] Furthermore, the molar ratio of the phenyl-containing silane, the alkenyl-containing silane, the hafnium source and the silane capping agent is 4:1:(0.1-0.2):0.05.

[0014] Furthermore, the molar ratio of the phenyl-containing silane, the alkenyl-containing silane, the hafnium source and the silane capping agent is 4:1:0.2:0.05.

[0015] Furthermore, the polysiloxane matrix is ​​obtained by first reacting a hafnium source, a phenyl-containing silane, and an alkenyl-containing silane under acidic conditions, separating them, and then continuing to react with a silane end-capping agent.

[0016] Furthermore, the reaction time is 2 to 10 hours, and the reaction temperature is 20 to 150° C.; the continued reaction time is 5 to 15 hours, and the continued reaction temperature is 10 to 100° C.

[0017] Furthermore, the reaction time is 8 hours, and the reaction temperature is 50-120°C; the continued reaction time is 9 hours, and the continued reaction temperature is 20-80°C.

[0018] Furthermore, the continued reaction is carried out under the action of tetramethylammonium hydroxide, and the molar ratio of the silane capping agent to tetramethylammonium hydroxide is 1:10.

[0019] Furthermore, a hydrogen-containing silane curing agent and a catalyst are added during the curing; the amount of the catalyst is a catalytic amount; the catalyst is a platinum catalyst, a titanate catalyst or an alkyl tin ester catalyst; the mass ratio of the polysiloxane matrix and the curing agent is (10-50):(10-30).

[0020] Furthermore, the catalyst is a platinum catalyst, and the mass ratio of the polysiloxane matrix to the curing agent is 30:18.3.

[0021] Furthermore, the curing agent is prepared using ethoxyphenylsilane and tetramethyldisiloxane as raw materials, and the molar ratio of the ethoxyphenylsilane to the tetramethyldisiloxane is 1:(6-24).

[0022] Furthermore, the molar ratio of the ethoxyphenylsilane to tetramethyldisiloxane is 1:18.

[0023] Furthermore, the preparation method of the curing agent is to mix ethoxyphenylsilane and tetramethyldisiloxane, and react to obtain the curing agent; the reaction temperature is -4 to 4°C, the reaction time is 0.1 to 2 hours, and the reaction condition is inert gas protection.

[0024] Furthermore, the reaction is carried out under the catalysis of tri(pentafluorophenyl)boron, and the amount of tri(pentafluorophenyl)boron used is a catalytic amount.

[0025] Furthermore, the inert gas is argon.

[0026] The present invention also provides a method for preparing the polysiloxane material, which comprises mixing a polysiloxane matrix, a curing agent and a catalyst, removing bubbles, and curing to obtain the polysiloxane material.

[0027] Furthermore, the curing temperature is 50 to 150° C., and the curing time is 2 to 10 hours.

[0028] Furthermore, the curing temperature is 80° C. and the curing time is 6 hours.

[0029] The present invention also provides use of the polysiloxane material in a flexible thermal protection coating or an ablation-resistant substrate material.

[0030] The present invention has achieved the following beneficial effects:

[0031] The present invention designs a hafnium hybrid carbon-rich siloxane system: during the ablation process, on the one hand, a continuous and stable carbon skeleton is constructed through the phenyl / vinyl carbon-rich structure; on the other hand, the Hf-O-Si structure is introduced into the polysiloxane main chain to promote the formation of SiHfOC composite ceramics at high temperature, which significantly improves the anti-ablation performance of flexible polysiloxane materials. It can be used as a matrix material for flexible thermal protective coatings, structural parts, etc., and has good application prospects in the field of thermal protective materials.

[0032] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.

[0033] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The invention relates to a preparation process of a carbon-rich hafnium hybrid polysiloxane matrix.

[0035] Figure 2 The infrared spectra of carbon-rich hafnium hybrid polysiloxane matrix HSR0 and HSR0.03.

[0036] Figure 3 The invention discloses a preparation process of a carbon-rich curing agent.

[0037] Figure 4 This is the hydrogen nuclear magnetic resonance spectrum of the carbon-rich curing agent.

[0038] Figure 5 Ablation performance test of hafnium hybrid carbon-rich polysiloxane ablative materials. (a) Optical photos of materials with different Hf / Si ratios after ablation; (b) Carbonization rate of materials with different Hf / Si ratios; (c) Mass ablation rate of materials with different Hf / Si ratios; (d) Carbon layer strength of materials with different Hf / Si ratios. DETAILED DESCRIPTION

[0039] The raw materials and equipment used in the present invention are all known products, which are obtained by purchasing commercially available products.

[0040] The following experiments without any explanation of temperature are reactions under normal temperature conditions, where normal temperature is room temperature, which is 25±5℃.

[0041] The “equivalents” mentioned in the following experiments are all molar amounts.

[0042] Example 1: Preparation of Hafnium Hybrid Carbon-Rich Polysiloxane Ablation Material

[0043] Preparation process of carbon-rich hafnium hybrid polysiloxane matrix Figure 1 shown.

[0044] 1. Preparation of Hafnium Dipropoxydiacetylacetonate Solution

[0045] Add 50mL of n-propanol and 10.03g of acetylacetone to the dropping funnel and mix well. Add 16g of hafnium tetrachloride to a 250mL three-necked flask, replace the gas with argon for 20 minutes, then place it in a 0℃ cold bath, start stirring, and slowly drop the mixed solution into it. After 2 hours of dropwise addition, heat to 95℃ to evaporate hydrogen chloride and continue the reaction for 4 hours. After the reaction is completed, add the reaction solution to a 100mL volumetric flask, add n-propanol to prepare a 100mL solution, and fill it with argon for protection. The hafnium content is 0.5mmol / ml, and the dipropoxy diacetylacetonate hafnium solution is obtained.

[0046] 2. Preparation of carbon-rich hafnium hybrid polysiloxane matrix

[0047] In a 500 mL single-mouth bottle, 4 equivalents of dimethoxymethylphenylsilane, 1 equivalent of dimethoxyvinylmethylsilane, 0, 0.05, 0.1, 0.15, 0.2, 0.25 equivalents of the dipropoxy diacetylacetonate hafnium solution prepared according to step 1 (respectively marked as HSR0, HSR0.01, HSR0.02, HSR0.03, HSR0.04, HSR0.05, indicating that Hf / Si is 0, 0.01, 0.02, 0.03, 0.04, 0.05, respectively, Hf / Si represents the molar ratio of Hf to Si element after the raw material dipropoxy diacetylacetonate hafnium solution, dimethoxymethylphenylsilane and dimethoxyvinylmethylsilane are mixed, Hf is hafnium) and 11 equivalents of dimethyl sulfoxide are added. The reactor single-mouth bottle is placed in a 50°C oil bath, and hydrochloric acid aqueous solution (HCl: H 2 O∶-OCH 3 The molar ratio is 0.0008:0.8:1, -OCH 3 Represents the molar amount of methoxy groups in the entire reaction system). After reacting for 2 hours, the temperature was raised to 80°C and the reaction was continued for 4 hours. The temperature was then raised to 120°C to evaporate the alcohol and water for 2 hours. The mixture was extracted with saturated brine / ethyl acetate and washed with water three times to completely separate DMSO. Finally, the solvent and unreacted monomers were evaporated at 100°C to obtain a primary hydrolysis product.

[0048] After cooling, the primary hydrolysis condensation product is dissolved in toluene again, and 0.05 equivalent of ethoxytrimethylsilane and 0.5 equivalent of tetramethylammonium hydroxide aqueous solution (25%) are added. After reacting for 1 hour, the temperature is raised to 80°C and the reaction is continued for 8 hours, and the cyclized product and oligomer are removed while the end capping is achieved. The reaction solution is washed with water three times, the organic phase is separated, and the solvent is finally evaporated at 80°C to obtain a carbon-rich hafnium hybrid polysiloxane matrix.

[0049] The infrared spectrum of carbon-rich hafnium hybrid polysiloxane matrix is ​​as follows Figure 2 As shown in the figure, the peak attributed to the silanol group almost completely disappeared, indicating that the end-capping was basically complete after the secondary condensation. -1 The shoulder peak near the surface is attributed to Si-O-Hf, which confirms the successful introduction of Hf. The vinyl content is calculated to be 1.46-1.50 mmol / g by dioxane calibration and NMR measurement.

[0050] 3: Preparation of carbon-rich curing agent

[0051] Preparation process of carbon-rich curing agent Figure 3 shown.

[0052] Add 1 equivalent of tetramethyldiphenylsilane, 2.2 equivalents of vinyltrimethoxysilane and platinum catalyst to a single-necked flask and dissolve them with n-hexane. Then replace the single-necked flask in the reactor with argon atmosphere and place it in a 50°C oil bath for 4 hours. Then, add activated carbon to remove the catalyst, filter out the activated carbon, and evaporate the solvent and excess vinyltriethoxysilane at 120°C to obtain ethoxyphenylsilane.

[0053] Add 18 equivalents of tetramethyldisiloxane and a catalytic amount of tri(pentafluorophenyl)borane to a three-necked flask, dissolve with n-hexane, replace with argon atmosphere and place in a 0°C cold bath. Use a peristaltic pump to drop 1 equivalent of ethoxyphenylsilane into the three-necked flask of the reactor. After the addition is complete, continue the reaction for 0.5h. Subsequently, add neutral alumina to remove the catalyst, filter out the alumina, and evaporate the solvent and excess tetramethyldisiloxane to obtain hydrogen-terminated branched phenylsilane, i.e., carbon-rich curing agent. The hydrogen nuclear magnetic resonance spectrum of the carbon-rich curing agent is as follows: Figure 4 As shown, the silicon hydrogen content is 3.05-3.10 mmol / g as calculated by NMR.

[0054] 4. Preparation of Hafnium Hybrid Carbon-Rich Polysiloxane Ablation Materials

[0055] The carbon-rich hafnium hybrid polysiloxane matrix obtained in step 2 of this embodiment and the carbon-rich curing agent obtained in step 3 of this embodiment are cured by casting.

[0056] Place the ablation sample mold in an 80℃ oven and preheat for 30min. Weigh 30g of carbon-rich hafnium hybrid polysiloxane matrix and 18.3g of carbon-rich curing agent into a beaker, add a magnetic stirrer for 1min until completely compatible, then drop 60μL of platinum catalyst and continue stirring for 3min. Remove the magnetic stirrer, place the beaker in a vacuum oven, and evacuate to remove bubbles. After the bubbles are completely removed, pour the mixture into the mold and react at 80℃ for 6h to completely cure and form, and obtain the hafnium hybrid carbon-rich polysiloxane ablation material.

[0057] The following is the preparation method of the control sample.

[0058] Comparative Example 1: Preparation of Commercial Polysiloxane

[0059] Referring to the curing process of step 4 of Example 1 of the present invention, the carbon-rich hafnium hybrid polysiloxane matrix was replaced by three commercial polysiloxane matrixes (side vinyl silicone oils purchased from Guangzhou Tianling Silica Gel Co., Ltd., Shanghai Silicon Friends New Materials and Shenzhen Jibo Silicon Fluoride, with vinyl contents of 0.52 mmol / g, 1.50 mmol / g, and 1.86 mmol / g, respectively), and the carbon-rich curing agent was replaced by 0.35 hydrogen-containing silicone oil purchased from Guangzhou Tianling Silica Gel Co., Ltd. to prepare three commercial polysiloxanes.

[0060] The beneficial effects of the present invention are demonstrated by experimental examples below.

[0061] Experimental Example 1: Ablation Performance of Hafnium Hybrid Carbon-Rich Polysiloxane Ablation Material

[0062] The ablation performance of the hafnium hybrid carbon-rich polysiloxane ablative material of the present invention and three commercial polysiloxanes was tested according to GJB 323A-96. The ablation heat flux was 4 MW / m 2 The ablation time is 20s. The optical photos after ablation are as follows Figure 5 As shown in a, it can be seen that when Hf / Si is 0.02-0.04, the bonding performance between the carbon layer and the original layer is significantly improved. Considering that the automatic peeling of the carbon layer will greatly affect the linear ablation rate results, the present invention only measures the samples with better carbon layer bonding. Among them, the linear ablation rates of the three samples HSR0.02, HSR0.03, and HSR0.04 are 0.0552mm / s, 0.0395mm / s, and 0.0154mm / s, respectively, which are far better than the ablation performance of the commercial polysiloxane in the comparative example 1 (at an ablation heat flux of 4MW / m 2 When the ablation time is 20s, the above three commercial polysiloxanes will be burned through). When Hf / Si is 0.04, the hybrid carbon-rich siloxane has the best ablation performance, and the carbonization rate is reduced by 36.62% compared with HSR0 ( Figure 5 b), the mass ablation rate decreased by 42.36% ( Figure 5c), the carbon layer strength increased by 333.3% ( Figure 5 d).

[0063] The above experimental results show that compared with commercial polysiloxane, the ablation performance of the hafnium hybrid carbon-rich polysiloxane ablative material of the present invention is significantly improved; among them, when Hf / Si is 0.04, the ablation performance of the obtained hafnium hybrid carbon-rich polysiloxane ablative material is optimal.

[0064] In summary, the present invention designs a hafnium hybrid carbon-rich siloxane system: during the ablation process, on the one hand, a continuous and stable carbon skeleton is constructed through the phenyl / vinyl carbon-rich structure; on the other hand, the Hf-O-Si structure is introduced into the polysiloxane main chain to promote the formation of SiHfOC composite ceramics at high temperature, which significantly improves the anti-ablation performance of flexible polysiloxane materials. It can be used as a matrix material for flexible thermal protective coatings, structural parts, etc., and has good application prospects in the field of thermal protective materials.

Claims

1. A polysiloxane material, characterized in that: The polysiloxane material is obtained by curing a polysiloxane matrix; the polysiloxane matrix is ​​prepared by reacting phenyl-containing silane, alkenyl-containing silane, hafnium source and silane end-capping agent as raw materials; the molar ratio of the phenyl-containing silane, alkenyl-containing silane, hafnium source and silane end-capping agent is (0.1-20):(0.01-10):(0.005-5):(0.001-1).

2. The polysiloxane material according to claim 1, characterized in that: The hafnium source is hafnium dimethoxydiacetylacetonate, hafnium diethoxydiacetylacetonate, hafnium di-n-propoxydiacetylacetonate, hafnium di-isopropoxydiacetylacetonate, hafnium tetramethoxy, hafnium tetraethoxy, hafnium tetra-n-propoxy, hafnium tetra-isopropoxy, hafnium tetrachloride, hafnium oxychloride, hafnium hydroxide, hafnium dichloride or hafnium acetylacetonate; The phenyl-containing silane is dimethoxymethylphenylsilane, dimethoxyethylphenylsilane, dimethoxydiphenylsilane, trimethoxyphenylsilane, diethoxymethylphenylsilane, diethoxyethylphenylsilane, diethoxydiphenylsilanesilane, triethoxyphenylsilane, dihydroxydiphenylsilane, diisopropoxymethylphenylsilane, diisopropoxyethylphenylsilane, diisopropoxydiphenylsilane, triisopropoxymethylphenylsilane, dichlorodiphenylsilane or dichloromethylphenylsilane; The alkenyl-containing silane is dimethoxymethylvinylsilane, dimethoxyethylvinylsilane, trimethoxymethylvinylsilane, diethoxymethylvinylsilane, diethoxyethylvinylsilane, triethoxyvinylsilane, diisopropoxymethylvinylsilane, diisopropoxyethylvinylsilane, triisopropoxyvinylsilane, dichloromethylvinylsilane, dichloroethylvinylsilane, trichlorovinylsilane or hydroxyl-terminated vinyl silicone oil; The silane end-capping agent is ethoxytrimethylsilane, methoxytrimethylsilane, isopropoxytrimethylsilane, chlorotrimethoxysilane, tetramethyldisiloxane, hexamethyldisiloxane or divinyltetramethyldisiloxane; The molar ratio of the phenyl-containing silane, the alkenyl-containing silane, the hafnium source and the silane end-capping agent is (1-10):(0.1-5):(0.05-0.5):(0.01-0.1).

3. The polysiloxane material according to claim 1 or 2, characterized in that: The molar ratio of the phenyl-containing silane, the alkenyl-containing silane, the hafnium source and the silane end-capping agent is 4:1:(0.1-0.2):0.05, preferably 4:1:0.2:0.

05.

4. The polysiloxane material according to claim 1, characterized in that: The polysiloxane matrix is ​​obtained by firstly reacting a hafnium source, a phenyl-containing silane and an alkenyl-containing silane under acidic conditions, separating them, and then continuing to react with a silane end-capping agent.

5. The method according to claim 4, characterized in that: The reaction time is 2 to 10 hours, and the reaction temperature is 20 to 150° C.; the continued reaction time is 5 to 15 hours, and the continued reaction temperature is 10 to 100° C.

6. The polysiloxane material according to claim 1, characterized in that: During the curing, a hydrogen-containing silane curing agent and a catalyst are added; the catalyst is a platinum catalyst, a titanate catalyst or an alkyl tin ester catalyst; and the mass ratio of the polysiloxane matrix to the curing agent is (10-50):(10-30).

7. The polysiloxane material according to claim 6, characterized in that: The catalyst is a platinum catalyst, and the mass ratio of the polysiloxane matrix to the curing agent is 30:18.

3.

8. The polysiloxane material according to claim 1, characterized in that: The curing agent is prepared using ethoxyphenylsilane and tetramethyldisiloxane as raw materials, and the molar ratio of the ethoxyphenylsilane to the tetramethyldisiloxane is 1:(6-24); preferably, the molar ratio of the ethoxyphenylsilane to the tetramethyldisiloxane is 1:

18.

9. A method for preparing the polysiloxane material according to any one of claims 1 to 8, characterized in that: The method comprises the steps of mixing a polysiloxane matrix, a curing agent and a catalyst, removing bubbles, and curing to obtain the polysiloxane.

10. Use of the polysiloxane material according to any one of claims 1 to 8 in a flexible thermal protective coating or an ablation-resistant substrate material.

Images