Fiber-reinforced weather-resistant and impact-resistant material for high-wave-transparent radome

Abstract

The invention discloses a fiber-reinforced weather-resistant and impact-resistant material for a high-wave-transparent radome, belongs to the technical field of wave-transparent materials, and aims to solve the technical problem that the wave-transparent performance and the impact resistance of a wave-transparent material in the prior art need to be further improved. The modified polytetrafluoroethylene composite fiber material is prepared from the following raw materials in parts by weight: 70 to 80 parts of modified polytetrafluoroethylene, 10 to 20 parts of composite fiber, 5 to 10 parts of modified curing agent and 14 to 29 parts of modified curing agent, the modified curing agent with a long-chain structure is prepared, and grafted polytetrafluoroethylene and a composite fiber precursor are subjected to surface modification through a side chain structure of the modified curing agent; in the process of mixing and sintering the modified polytetrafluoroethylene and the composite fiber with auxiliary materials, an oxazine ring in a modified curing agent component is subjected to ring opening polymerization, so that the curing efficiency of the material is improved, and the antenna housing material is obtained.

Description

Technical Field

[0001] This invention relates to the field of wave-transparent materials technology, specifically to a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant material for a radome. Background Technology

[0002] The development of high-transmittance radome materials has evolved from glass fiber reinforced resin to high-performance polymer composite materials. Early glass fiber radomes suffered from high dielectric constant and moderate weather resistance, resulting in significant losses in high-frequency applications. With the development of radar, 5G communication, and aerospace technologies, the demand for low-dielectric, low-loss, high-weather-resistant, and impact-resistant materials has been increasing. In recent years, low-dielectric matrix materials such as PTFE, PEEK, and silicone resins have been gradually applied, combined with reinforcing phases such as SiO2 fibers and aramid fibers to improve transmittance and weather resistance. Furthermore, optimization through technologies such as nano-SiO2, BN modification, UV stabilizers, and fluorocarbon coatings has further enhanced the long-term stability and environmental adaptability of the materials, enabling their widespread application in high-end fields such as aerospace, 5G millimeter-wave radar, and stealth radomes.

[0003] The prior art CN104059601B discloses a method for synthesizing a phosphate-based microwave-transparent material. An inorganic adhesive is used as a base material, and an organic microwave-transparent material is used as a template agent. After being mixed evenly, the mixture is added to a mold, left to stand for 24 hours, and cured at 60-80℃. During the curing process, the mixture is flattened every 1 hour. After curing, the mixture is calcined at 600-800℃ to obtain the phosphate-based microwave-transparent material. The prepared phosphate-based microwave-transparent material has excellent high-temperature resistance and microwave transmission properties.

[0004] However, the aforementioned patent only describes the process of obtaining a phosphate-based microwave-transparent material by using an organic microwave-transparent material as a template agent and then curing it. However, the prepared phosphate-based microwave-transparent material has a simple structure, resulting in poor impact toughness and susceptibility to changes in humidity and temperature, leading to hydrolysis or swelling and deterioration of microwave transmission performance. Therefore, the impact resistance and microwave transmission performance of the material need to be further improved.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for radomes, which addresses the technical problem that the wave transmission performance and impact resistance of existing wave-transparent materials need further improvement.

[0007] The objective of this invention can be achieved through the following technical solution: a fiber-reinforced high-transparency radome weather-resistant and impact-resistant material, comprising the following raw material components by weight: 70-80 parts modified polytetrafluoroethylene, 10-20 parts composite fiber, 5-10 parts modified curing agent and 14-29 parts auxiliary materials;

[0008] The auxiliary materials include the following materials in parts by weight: 0.5-2 parts UV stabilizer, 5-10 parts toughening agent, 0.5-2 parts antioxidant, 5-10 parts filler and 3-5 parts flame retardant.

[0009] Furthermore, the UV stabilizer is one or both of benzophenone and benzotriazole; the toughening agent is one or more of butadiene, maleic anhydride and styrene; the antioxidant is one or both of hydroquinone and tricyclohexylphosphine; the filler is one or both of talc and mica powder; and the flame retardant is one or more of decabromodiphenyl ether, melamine and triphenyl phosphate.

[0010] Furthermore, the preparation method of modified polytetrafluoroethylene includes the following steps:

[0011] A1. Add polytetrafluoroethylene powder to a radio frequency plasma reactor, and after plasma treatment, let it stand in air for 10-15 minutes to obtain activated polytetrafluoroethylene.

[0012] A2. Allyl glycidyl ether and N,N-dimethylformamide were added to the reaction vessel and stirred. After the temperature of the reaction vessel was raised to 40-60℃, activated polytetrafluoroethylene and triethylamine were added to the reaction vessel. After stirring for 30-40 minutes, the grafted polytetrafluoroethylene was obtained through post-treatment.

[0013] A3. Add the modified curing agent and N,N-dimethylformamide to the reactor and stir. After the reactor temperature is raised to 60-80℃, add grafted polytetrafluoroethylene and azobisisobutyronitrile to the reactor. After stirring for 1-2 hours, the modified polytetrafluoroethylene is obtained through post-treatment.

[0014] The reaction principle for preparing modified polytetrafluoroethylene (PTFE) is as follows: After plasma activation, a large number of active hydrophilic functional groups such as hydroxyl, aldehyde, and carboxyl groups are generated on the surface of PTFE powder. Under alkaline conditions, allyl glycidyl ether ring-opening generates free radicals that react with the activated functional groups on the activated PTFE to obtain grafted PTFE with a double bond structure. Finally, under the catalysis of free radical initiator and high temperature, the double bond structure on the grafted PTFE undergoes a free radical polymerization reaction with the double bonds of the side chain of the modified curing agent, and finally, modified PTFE is prepared.

[0015] Furthermore, in step A1, the atmosphere of the radio frequency plasma reactor is argon, the radio frequency power is 13.64MHz, the fixed venting pressure is 50-70Pa, and the discharge power is 40-60W.

[0016] Further, in step A2, the ratio of allyl glycidyl ether, N,N-dimethylformamide, activated polytetrafluoroethylene and triethylamine is 2-3g:36-40mL:8-10g:0.3-0.6g. The post-treatment includes: after the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction liquid to collect the filter cake, transfer the filter cake to a drying oven at a temperature of 60-80℃ and vacuum dry it to constant weight to obtain grafted polytetrafluoroethylene.

[0017] Further, in step A3, the ratio of modified curing agent, N,N-dimethylformamide, grafted polytetrafluoroethylene, and azobisisobutyronitrile is 3-4g:40-45mL:9-12g:0.2-0.4g. The post-treatment includes: after the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction liquid to collect the filter cake, transfer the filter cake to a drying oven at a temperature of 60-80℃ and vacuum dry it to constant weight to obtain modified polytetrafluoroethylene.

[0018] Furthermore, the preparation method of composite fibers includes the following steps:

[0019] B1. Add aluminum chloride, tetraethyl silicate and deionized water to a hydrothermal reactor. Stir at room temperature for 10-15 min, then add aluminum triisopropoxy and polyvinyl alcohol. Raise the temperature of the hydrothermal reactor to 160-180℃ and keep it at that temperature for 8-12 h to obtain a composite gel.

[0020] B2. The composite gel is added to an electrospinning machine, and modified fibers are obtained by electrospinning. The modified fibers are then post-treated to obtain porous fibers.

[0021] B3. The modified fibers are impregnated and modified in phosphate slurry for 3-5 times to obtain composite fiber precursors;

[0022] B4. Add the composite fiber precursor and N,N-dimethylformamide to the reactor and stir. After the reactor temperature is raised to 40-60℃, continue to add the modified curing agent to the reactor and adjust the pH of the reaction system to 8-10 using saturated sodium hydroxide solution. After stirring for 30-40 minutes, the composite fiber is obtained through post-treatment.

[0023] The reaction principle for preparing composite fibers is as follows: under hydrothermal conditions, metal-organic salts and metal-inorganic salts are hydrolyzed to produce a gel-like structure. After high-temperature calcination and steam activation, porous fibers with high surface activity are obtained. After being modified by soaking in phosphate slurry, the surface of the composite fiber precursor is finally modified by hydrolyzing the silane coupling agent on the modified curing agent branch under alkaline conditions to obtain composite fibers.

[0024] Furthermore, in step B1, the ratio of aluminum chloride, tetraethyl silicate, deionized water, aluminum triisopropoxy, and polyvinyl alcohol is 12-15g:8-10g:40-50mL:9-12g:1-2g.

[0025] Furthermore, in step B2, the electrospinning process requirements are as follows: temperature 20-25℃, humidity 25-35%, applied voltage 18-21kV, receiving distance 18-20cm, infusion rate 4-6mL / h, slide table moving speed 24-30cm / min, and receiving roller rotation speed 24-30r / min; the post-treatment operation is as follows: the modified fiber is transferred to a tube furnace, nitrogen gas is introduced into the tube furnace for protection, and the tube furnace is heated to 5-6℃. The temperature is increased to 600-650℃ at a heating rate of 1-2L / min. Nitrogen gas is then introduced at a flow rate of 1-2L / min. After holding at this temperature for 1-2 hours, the oxygen gas is turned off, and nitrogen gas is introduced again. The temperature is then increased to 1250-1350℃ at a heating rate of 5-6℃ / min. After holding at this temperature for 1-2 hours, the temperature is allowed to cool naturally to 120-150℃. Nitrogen gas is then turned off, and water vapor is introduced at a flow rate of 1-2L / min. After holding at this temperature for 1-2 hours, porous fibers are obtained.

[0026] Furthermore, in step B3, the padding modification operation is as follows: after a two-dip and two-roll process, the material is transferred to an oven at 150-180℃, cured to constant weight in a nitrogen atmosphere, and then naturally cooled to room temperature to obtain a composite fiber precursor, wherein the liquor ratio is 1:20-24 and the padding rate is 100-110%;

[0027] Furthermore, in step B4, the ratio of composite fiber precursor, N,N-dimethylformamide and modified curing agent is 6-8g:24-30mL:2-3g. The post-treatment includes: after the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction liquid to collect the filter cake, transfer the filter cake to a drying oven at a temperature of 60-80℃ and vacuum dry it to constant weight to obtain composite fiber.

[0028] Furthermore, the method for preparing phosphate slurry includes the following steps: adding phosphoric acid solution and aluminum hydroxide into a reaction vessel, raising the temperature of the reaction vessel to 60-80℃, stirring and maintaining the temperature until the solution becomes clear, adding chromium oxide and hydrogen peroxide into the reaction vessel, stirring and maintaining the temperature for 2-3 hours to obtain phosphate slurry.

[0029] The preparation principle of phosphate slurry is as follows: phosphoric acid and alumina react to prepare phosphate structure, and under acidic conditions, hydrogen peroxide converts hexavalent chromium into trivalent chromium ions, which are then complexed with phosphate to finally prepare phosphate slurry.

[0030] Furthermore, the concentration of the phosphoric acid solution is 40-60 wt%, and the ratio of phosphoric acid solution, aluminum hydroxide, chromium oxide and hydrogen peroxide is 40-60 mL: 2.4-3.0 g: 1.4-1.6 g: 0.4-0.6 g.

[0031] Furthermore, the preparation method of the modified curing agent includes the following steps:

[0032] C1. Add glycidyltrimethoxysilane, 1,3-diamino-2-hydroxypropane, triethylamine and N,N-dimethylformamide to a reaction vessel, raise the temperature of the reaction vessel to 40-60℃, and keep the reaction at this temperature for 30-40 min to obtain modified siloxane.

[0033] C2. Add the modified siloxane and tetrahydrofuran to the reflux apparatus. After purging with nitrogen for protection, lower the temperature of the reflux apparatus to 0-3℃. Continue to add formaldehyde solution to the reactor. After stirring at the temperature for 30-40 minutes, add 6-methyljuncusiol solution dropwise to the reactor. After the addition is complete, raise the temperature of the reflux apparatus back to reflux and keep the reaction at the temperature for 18-20 hours. The modified curing agent is then obtained through post-treatment.

[0034] The reaction equation for preparing the modified curing agent is as follows:

[0035]

[0036] In the formula: .

[0037] The reaction principle for preparing the modified curing agent is as follows: Under alkaline conditions, the epoxy group on glycidyltrimethoxysilane undergoes ring opening to generate free radicals, which react with the hydroxyl groups on 1,3-diamino-2-hydroxypropane to prepare the modified siloxane. The mass spectrometry analysis data of the modified siloxane are: m / z: 181.4 (100.0%), 181.9 (10.8%), 182.8 (4.8%). Under nitrogen protection, the diamino group, formaldehyde, and hydroxyl groups on 6-methyljuncosyl hydroxyl groups on the modified siloxane undergo cyclization reactions to form a polyoxazine-structured modified curing agent.

[0038] Further, in step C1, the ratio of glycidyltrimethoxysilane, 1,3-diamino-2-hydroxypropane, triethylamine, and N,N-dimethylformamide is 4-6 g: 2-3 g: 0.2-0.5 g: 25-30 mL. The post-treatment includes: after the reaction is completed, the reaction vessel is cooled to room temperature, the reaction solution is added to a rotary evaporator with a water bath temperature of 80-100℃, and the solution is distilled under reduced pressure until no liquid is collected, thus obtaining the modified siloxane.

[0039] Further, in step C2, the ratio of modified siloxane, tetrahydrofuran, formaldehyde solution, and 6-methyljuncuspidol solution is 8.1-9.9g:30-32mL:20-24mL:40-50mL. The formaldehyde solution is obtained by mixing formaldehyde gas and tetrahydrofuran at a ratio of 3.6-4.4g:20-24mL, and the 6-methyljuncuspidol solution is obtained by mixing 6-methyljuncuspidol and tetrahydrofuran at a ratio of 9.9-12.1g:40-50mL. The post-treatment includes: after the reaction is complete, the reaction vessel is cooled to room temperature, and the reaction solution is added to a rotary evaporator with a water bath temperature of 80-100℃. The mixture is then distilled under reduced pressure until no liquid is collected, yielding the modified curing agent.

[0040] Furthermore, a method for preparing a fiber-reinforced high-transparency, weather-resistant, and impact-resistant radome material is as follows: modified polytetrafluoroethylene, composite fiber, modified curing agent, UV stabilizer, toughening agent, antioxidant, filler, and flame retardant are added to a melting bath at a temperature of 250-280℃ and stirred for 20-30 minutes. The melt is then transferred to a vacuum sintering furnace and sintered to obtain the radome material.

[0041] The reaction mechanism of high-temperature curing is as follows:

[0042]

[0043] The reaction principle of high-temperature curing is as follows: In the oxazine epoxy carbon-nitrogen ring structure, due to the electronic effect of the heteroatoms of oxygen and nitrogen atoms, the electron cloud density of the carbon atom in the middle is reduced, thus giving it a partial positive charge. During the ring-opening curing process, the carbon-oxygen bond first breaks into oxygen anions and carbocations. The carbocation intermediate randomly attacks the carbon atoms adjacent to the oxygen on the benzene ring, thereby initiating polymerization. Through the polymerization reaction of the modified curing agent, composite fiber and modified polytetrafluoroethylene oxazine ring, the materials are tightly bonded together, and finally the radome material is prepared.

[0044] Further, the sintering operation is as follows: under a nitrogen atmosphere, the temperature of the sintering furnace is raised to 350-400℃ at a heating rate of 8-10℃ / min, and sintered at a constant temperature for 2-4 hours. Then, the temperature is lowered to 120-150℃ at a cooling rate of 4-5℃ / min, and allowed to cool naturally to room temperature to obtain the radome material.

[0045] The present invention has the following beneficial effects:

[0046] 1. This invention involves preparing a long-chain modified curing agent, modifying the surface of grafted polytetrafluoroethylene (PTFE) and composite fiber precursors through its side chain structure, and obtaining modified PTFE and composite fibers. During the sintering process with auxiliary materials, the oxazine rings in the modified curing agent components undergo ring-opening polymerization, improving the curing efficiency of the material, thereby obtaining an antenna radome material. The siloxane structure inside the material enhances the weather resistance of the material, while working synergistically with the phosphate structure. During combustion, the generated silica protective layer and carbonization effect work together to significantly enhance the flame retardant effect of the material. Furthermore, the inherent low-loss characteristics of PTFE and the synergistic effect of the composite fibers significantly improve the wave transmission performance of the material.

[0047] 2. This invention also prepares a modified curing agent with siloxane and double bond structures in the side chains. This agent modifies the modified fibers through siloxane hydrolysis, thereby enhancing the stability and compatibility of the modified fibers with organic materials. Furthermore, it modifies the activated grafted polyvinylidene fluoride segments using free radical polymerization. The siloxane structure on the surface synergistically enhances the material's weather resistance with the silica component in the modified fibers. Simultaneously, the two, along with the alumina and phosphate inside the modified fibers, further enhance the flame retardant properties of the material through a synergistic flame retardant effect. Moreover, during high-temperature processing, the oxazine ring in the modified curing agent undergoes ring-opening polymerization, tightly binding the modified polytetrafluoroethylene and the composite fibers, thus significantly enhancing the material's impact resistance.

[0048] 3. In the process of preparing modified polytetrafluoroethylene (PTFE) fibers, this invention first obtains a porous fiber through hydrolysis, electrospinning, and high-temperature calcination. Besides enhancing the fiber's wave transmission performance through phosphate modification, the flame retardant performance is further enhanced through the component composite flame retardant effect. After modification with a curing agent and coating with highly hydrophobic modified PTFE, the fiber is isolated from water, significantly improving the stability of the phosphate structure. Furthermore, the inherent low-loss characteristics of PTFE, when filled with silica fiber, form a gradient dielectric structure, thereby reducing electromagnetic wave reflection at different medium interfaces and increasing wave transmittance. The phosphate provides a uniformly distributed low-loss phase within the material, improving wave transmission uniformity and enhancing material stability. Through the synergistic effect of these three factors, the wave transmission performance of the material is enhanced. Detailed Implementation

[0049] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] The polytetrafluoroethylene powder used in this invention was purchased from Nanjing Tianshi New Material Technology Co., Ltd., and the model is PTFE-200D.

[0051] Example 1

[0052] This embodiment provides a method for preparing a modified curing agent for a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant radome material, comprising the following steps:

[0053] Step 1: Preparation of modified siloxanes

[0054] Weigh out 400.0 g of glycidyltrimethoxysilane, 200.0 g of 1,3-diamino-2-hydroxypropane, 20.0 g of triethylamine and 2500.0 mL of N,N-dimethylformamide and add them to a reaction vessel. Raise the temperature of the reaction vessel to 40 °C and keep it at that temperature for 30 min. After the reaction is complete, cool the reaction vessel to room temperature and add the reaction solution to a rotary evaporator with a water bath temperature of 80 °C. Distill under reduced pressure until no liquid is collected to obtain modified siloxane.

[0055] Step 2: Preparation of modified curing agent

[0056] Weigh out 360.0g of formaldehyde gas and 2000.0mL of tetrahydrofuran and mix them to obtain a formaldehyde solution;

[0057] Weigh out 990.0g of 6-methyljunposide and mix with 4000.0mL of tetrahydrofuran to obtain a 6-methyljunposide solution;

[0058] Weigh 810.0 g of modified siloxane and 3000.0 mL of tetrahydrofuran and add them to the reflux apparatus. After purging with nitrogen for protection, the temperature of the reflux apparatus is lowered to 0°C. 2000.0 mL of formaldehyde solution is then added to the reactor. After stirring at this temperature for 30 min, 4000.0 mL of 6-methyljuncierol solution is added dropwise to the reactor. After the addition is complete, the temperature of the reflux apparatus is raised back to reflux. The reaction is maintained at this temperature for 18 h. After the reaction is complete, the reactor is cooled to room temperature. The reaction solution is then added to a rotary evaporator with a water bath temperature of 80°C and distilled under reduced pressure until no liquid is collected, thus obtaining the modified curing agent.

[0059] Example 2

[0060] This embodiment provides a method for preparing a modified curing agent for a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant radome material, comprising the following steps:

[0061] Step 1: Preparation of modified siloxanes

[0062] Weigh out 600.0 g of glycidyltrimethoxysilane, 300.0 g of 1,3-diamino-2-hydroxypropane, 50.0 g of triethylamine and 3000.0 mL of N,N-dimethylformamide and add them to a reaction vessel. Raise the temperature of the reaction vessel to 60 °C and keep it at that temperature for 40 min. After the reaction is complete, cool the reaction vessel to room temperature and add the reaction solution to a rotary evaporator with a water bath temperature of 100 °C. Distill under reduced pressure until no liquid is collected to obtain modified siloxane.

[0063] Step 2: Preparation of modified curing agent

[0064] Weigh out 440.0g of formaldehyde gas and 2400.0mL of tetrahydrofuran and mix them to obtain a formaldehyde solution;

[0065] Weigh out 1210.0g of 6-methyljunposide and mix with 5000.0mL of tetrahydrofuran to obtain a 6-methyljunposide solution;

[0066] Weigh out 990.0 g of modified siloxane and 3200.0 mL of tetrahydrofuran and add them to the reflux apparatus. After purging with nitrogen for protection, lower the temperature of the reflux apparatus to 0°C. Continue to add 2400.0 mL of formaldehyde solution to the reactor. After stirring at the same temperature for 40 min, add 5000.0 mL of 6-methyljuncusiol solution dropwise to the reactor. After the addition is complete, raise the temperature of the reflux apparatus back to reflux and keep the reaction at the same temperature for 20 h. After the reaction is complete, cool the reactor to room temperature and add the reaction solution to a rotary evaporator with a water bath temperature of 100°C. Distill under reduced pressure until no liquid is collected to obtain the modified curing agent.

[0067] Example 3

[0068] This embodiment provides a method for preparing a modified curing agent for a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant radome material, comprising the following steps:

[0069] Step 1: Preparation of modified siloxanes

[0070] Weigh out 500.0 g of glycidyltrimethoxysilane, 250.0 g of 1,3-diamino-2-hydroxypropane, 36.0 g of triethylamine and 2700.0 mL of N,N-dimethylformamide and add them to a reaction vessel. Raise the temperature of the reaction vessel to 50 °C and keep it at that temperature for 36 min. After the reaction is complete, cool the reaction vessel to room temperature and add the reaction solution to a rotary evaporator with a water bath temperature of 90 °C. Distill under reduced pressure until no liquid is collected to obtain modified siloxane.

[0071] Step 2: Preparation of modified curing agent

[0072] Weigh out 400.0g of formaldehyde gas and 2100.0mL of tetrahydrofuran and mix them to obtain a formaldehyde solution;

[0073] Weigh out 1100.0g of 6-methyljunposide and mix with 4500.0mL of tetrahydrofuran to obtain a 6-methyljunposide solution;

[0074] Weigh 900.0 g of modified siloxane and 3200.0 mL of tetrahydrofuran and add them to the reflux apparatus. After purging with nitrogen for protection, the temperature of the reflux apparatus is lowered to 1°C. 2100.0 mL of formaldehyde solution is then added to the reactor. After stirring at this temperature for 36 min, 4500.0 mL of 6-methyljuncusiol solution is added dropwise to the reactor. After the addition is complete, the temperature of the reflux apparatus is raised back to reflux, and the reaction is maintained at this temperature for 18 h. After the reaction is complete, the reactor is cooled to room temperature, and the reaction solution is added to a rotary evaporator with a water bath temperature of 90°C. The solution is then distilled under reduced pressure until no liquid is collected, yielding the modified curing agent.

[0075] Example 4

[0076] This embodiment provides a method for preparing modified polytetrafluoroethylene (PTFE) as a weather-resistant and impact-resistant material for fiber-reinforced high-transparency radomes, comprising the following steps:

[0077] Step ①: Preparation of activated polytetrafluoroethylene

[0078] Weigh 1200.0g of polytetrafluoroethylene powder and add it to the radio frequency plasma reactor. The atmosphere of the radio frequency plasma reactor is argon, the radio frequency power is 13.64MHz, the fixed exhaust pressure is 50Pa, and the discharge power is 40W. After plasma treatment, let it stand in air for 10min to obtain activated polytetrafluoroethylene.

[0079] Step ②: Preparation of grafted polytetrafluoroethylene

[0080] Weigh out 200.0g of allyl glycidyl ether and 3600.0mL of N,N-dimethylformamide and add them to the reaction vessel and stir. After the temperature of the reaction vessel is raised to 40℃, add 800.0g of activated polytetrafluoroethylene and 30.0g of triethylamine to the reaction vessel. Keep the mixture warm and stir for 30min. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction liquid and collect the filter cake. Transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain grafted polytetrafluoroethylene.

[0081] Step ③: Preparation of modified polytetrafluoroethylene

[0082] Weigh 300.0g of the modified curing agent prepared in Example 1 and 4000.0mL of N,N-dimethylformamide and add them to the reaction vessel and stir. After the temperature of the reaction vessel is raised to 60°C, add 900.0g of grafted polytetrafluoroethylene and 20.0g of azobisisobutyronitrile to the reaction vessel. After stirring at the temperature for 1 hour, after the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction liquid and collect the filter cake. Transfer the filter cake to a drying oven at 60°C and vacuum dry it to constant weight to obtain modified polytetrafluoroethylene.

[0083] Example 5

[0084] This embodiment provides a method for preparing modified polytetrafluoroethylene (PTFE) as a weather-resistant and impact-resistant material for fiber-reinforced high-transparency radomes, comprising the following steps:

[0085] Step ①: Preparation of activated polytetrafluoroethylene

[0086] Weigh 1200.0g of polytetrafluoroethylene powder and add it to the radio frequency plasma reactor. The atmosphere of the radio frequency plasma reactor is argon, the radio frequency power is 13.64MHz, the fixed exhaust pressure is 70Pa, and the discharge power is 60W. After plasma treatment, let it stand in air for 15min to obtain activated polytetrafluoroethylene.

[0087] Step ②: Preparation of grafted polytetrafluoroethylene

[0088] Weigh out 300.0 g of allyl glycidyl ether and 4000.0 mL of N,N-dimethylformamide and add them to the reaction vessel and stir. After the temperature of the reaction vessel is raised to 60°C, add 1000.0 g of activated polytetrafluoroethylene and 60.0 g of triethylamine to the reaction vessel. After stirring for 40 min, the reaction is completed. After the temperature of the reaction vessel is lowered to room temperature, filter the reaction liquid and collect the filter cake. Transfer the filter cake to a drying oven at 80°C and vacuum dry it to constant weight to obtain grafted polytetrafluoroethylene.

[0089] Step ③: Preparation of modified polytetrafluoroethylene

[0090] Weigh 400.0g of the modified curing agent prepared in Example 2 and 4500.0mL of N,N-dimethylformamide and add them to the reaction vessel and stir. After the temperature of the reaction vessel is raised to 80°C, add 1200.0g of grafted polytetrafluoroethylene and 40.0g of azobisisobutyronitrile to the reaction vessel. After stirring for 2 hours, the reaction is completed. After the temperature of the reaction vessel is lowered to room temperature, filter the reaction liquid and collect the filter cake. Transfer the filter cake to a drying oven at 80°C and vacuum dry it to constant weight to obtain modified polytetrafluoroethylene.

[0091] Example 6

[0092] This embodiment provides a method for preparing modified polytetrafluoroethylene (PTFE) as a weather-resistant and impact-resistant material for fiber-reinforced high-transparency radomes, comprising the following steps:

[0093] Step ①: Preparation of activated polytetrafluoroethylene

[0094] Weigh 1200.0g of polytetrafluoroethylene powder and add it to the radio frequency plasma reactor. The atmosphere of the radio frequency plasma reactor is argon, the radio frequency power is 13.64MHz, the fixed exhaust pressure is 60Pa, and the discharge power is 50W. After plasma treatment, let it stand in air for 12min to obtain activated polytetrafluoroethylene.

[0095] Step ②: Preparation of grafted polytetrafluoroethylene

[0096] Weigh out 250.0g of allyl glycidyl ether and 3600.0mL of N,N-dimethylformamide and add them to the reaction vessel and stir. After the temperature of the reaction vessel is raised to 50℃, add 900.0g of activated polytetrafluoroethylene and 45.0g of triethylamine to the reaction vessel. After stirring for 36min, the reaction is completed. After the temperature of the reaction vessel is lowered to room temperature, filter the reaction liquid and collect the filter cake. Transfer the filter cake to a drying oven at 70℃ and vacuum dry it to constant weight to obtain grafted polytetrafluoroethylene.

[0097] Step ③: Preparation of modified polytetrafluoroethylene

[0098] Weigh 360.0g of the modified curing agent prepared in Example 3 and 4200.0mL of N,N-dimethylformamide and add them to the reaction vessel and stir. After the temperature of the reaction vessel is raised to 70°C, add 1000.0g of grafted polytetrafluoroethylene and 30.0g of azobisisobutyronitrile to the reaction vessel. After stirring for 2 hours, after the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction liquid and collect the filter cake. Transfer the filter cake to a drying oven at 70°C and vacuum dry it to constant weight to obtain modified polytetrafluoroethylene.

[0099] Example 7

[0100] This embodiment provides a method for preparing composite fibers for a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant radome, comprising the following steps:

[0101] Step I: Preparation of phosphate slurry

[0102] Weigh out 4000.0 mL of 40 wt% phosphoric acid solution and 240.0 g of aluminum hydroxide and add them to the reactor. Raise the temperature of the reactor to 60°C and keep it warm while stirring until the solution is clear. Then add 140.0 g of chromium oxide and 40.0 g of hydrogen peroxide to the reactor and keep it warm while stirring for 2 hours to obtain phosphate slurry.

[0103] Step II: Preparation of composite gel

[0104] Weigh out 1200.0g aluminum chloride, 800.0g tetraethyl silicate and 4000.0mL deionized water and add them to a hydrothermal reactor. Stir at room temperature for 10min, then add 900.0g aluminum triisopropoxy and 100.0g polyvinyl alcohol. Raise the temperature of the hydrothermal reactor to 160℃ and keep it at that temperature for 8h to obtain a composite gel.

[0105] Step III: Preparation of porous fibers

[0106] The composite gel was added to an electrospinning machine. The electrospinning temperature was 20℃, the humidity was 25%, the applied voltage was 18kV, the receiving distance was 18cm, the infusion rate was 4mL / h, the slide table moving speed was 24cm / min, and the receiving roller speed was 24r / min. Modified fibers were obtained by electrospinning and transferred to a tube furnace. After nitrogen protection was introduced into the tube furnace, the temperature was raised to 600℃ at a heating rate of 5℃ / min. The nitrogen was then turned off, and oxygen was introduced at a flow rate of 1L / min. After holding at this temperature for 1h, the oxygen was turned off, and nitrogen was introduced again. The temperature was raised to 1250℃ at a heating rate of 5℃ / min. After holding at this temperature for 1h, the temperature was naturally cooled to 120℃. The nitrogen was then turned off, and water vapor was introduced at a flow rate of 1L / min. After holding at this temperature for 1h, porous fibers were obtained.

[0107] Step IV: Preparation of composite fiber precursor

[0108] Modified fibers were impregnated in phosphate slurry and subjected to a two-impregnation and two-roll process with a bath ratio of 1:20 and an impregnation rate of 100%. The material was then transferred to an oven at 250°C and cured to constant weight in a nitrogen atmosphere. This process was repeated three times to obtain the composite fiber precursor.

[0109] Step V: Preparation of composite fibers

[0110] Weigh 600.0g of composite fiber precursor and 2400.0mL of N,N-dimethylformamide and add them to the reaction vessel. Stir the mixture. After the temperature of the reaction vessel is raised to 40℃, add 200.0g of the modified curing agent prepared in Example 1 to the reaction vessel and adjust the pH of the reaction system to 8 using saturated sodium hydroxide solution. After stirring for 30min, the reaction is completed. After the temperature of the reaction vessel is lowered to room temperature, filter the reaction liquid and collect the filter cake. Transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain composite fiber.

[0111] Example 8

[0112] This embodiment provides a method for preparing composite fibers for a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant radome, comprising the following steps:

[0113] Step I: Preparation of phosphate slurry

[0114] Weigh out 6000.0 mL of 60 wt% phosphoric acid solution and 300.0 g of aluminum hydroxide and add them to the reactor. Raise the temperature of the reactor to 80°C and keep it warm while stirring until the solution is clear. Then add 160.0 g of chromium oxide and 60.0 g of hydrogen peroxide to the reactor and keep it warm while stirring for 3 hours to obtain phosphate slurry.

[0115] Step II: Preparation of composite gel

[0116] Weigh out 1500.0g aluminum chloride, 1000.0g tetraethyl silicate and 5000.0mL deionized water and add them to a hydrothermal reactor. Stir at room temperature for 15min, then add 1200.0g aluminum triisopropoxy and 200.0g polyvinyl alcohol. Raise the temperature of the hydrothermal reactor to 180℃ and keep it at that temperature for 12h to obtain a composite gel.

[0117] Step III: Preparation of porous fibers

[0118] The composite gel was added to an electrospinning machine. The electrospinning temperature was 25℃, the humidity was 35%, the applied voltage was 21kV, the receiving distance was 20cm, the infusion rate was 6mL / h, the slide table moving speed was 30cm / min, and the receiving roller speed was 30r / min. Modified fibers were obtained by electrospinning and transferred to a tube furnace. After nitrogen protection was introduced into the tube furnace, the temperature was raised to 650℃ at a heating rate of 6℃ / min. The nitrogen was then turned off, and oxygen was introduced at a flow rate of 2L / min. After holding at this temperature for 2h, the oxygen was turned off, and nitrogen was introduced again. The temperature was raised to 1350℃ at a heating rate of 6℃ / min. After holding at this temperature for 2h, the temperature was naturally cooled to 150℃. The nitrogen was then turned off, and water vapor was introduced at a flow rate of 2L / min. After holding at this temperature for 2h, porous fibers were obtained.

[0119] Step IV: Preparation of composite fiber precursor

[0120] Modified fibers were impregnated in phosphate slurry and subjected to a two-impregnation and two-rolling process with a bath ratio of 1:24 and an impregnation rate of 110%. The material was then transferred to an oven at 280°C and cured to constant weight in a nitrogen atmosphere. This process was repeated 5 times to obtain the composite fiber precursor.

[0121] Step V: Preparation of composite fibers

[0122] Weigh 800.0g of composite fiber precursor and 3000.0mL of N,N-dimethylformamide and add them to the reaction vessel. Stir the mixture. After the temperature of the reaction vessel is raised to 60℃, add 300.0g of the modified curing agent prepared in Example 2 to the reaction vessel and adjust the pH of the reaction system to 10 using saturated sodium hydroxide solution. After stirring for 40min, once the reaction is complete, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction liquid and collect the filter cake. Transfer the filter cake to a drying oven at 80℃ and vacuum dry it to constant weight to obtain composite fiber.

[0123] Example 9

[0124] This embodiment provides a method for preparing composite fibers for a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant radome, comprising the following steps:

[0125] Step I: Preparation of phosphate slurry

[0126] Weigh out 5000.0 mL of 50 wt% phosphoric acid solution and 270.0 g of aluminum hydroxide and add them to the reactor. Raise the temperature of the reactor to 70°C and keep it warm while stirring until the solution is clear. Then add 150.0 g of chromium oxide and 50.0 g of hydrogen peroxide to the reactor and keep it warm while stirring for 3 hours to obtain phosphate slurry.

[0127] Step II: Preparation of composite gel

[0128] Weigh out 1350.0g aluminum chloride, 900.0g tetraethyl silicate and 4500.0mL deionized water and add them to a hydrothermal reactor. Stir at room temperature for 12min, then add 1000.0g aluminum triisopropoxy and 160.0g polyvinyl alcohol. Raise the temperature of the hydrothermal reactor to 170℃ and keep it at that temperature for 10h to obtain a composite gel.

[0129] Step III: Preparation of porous fibers

[0130] The composite gel was added to an electrospinning machine. The electrospinning temperature was 21℃, the humidity was 30%, the applied voltage was 20kV, the receiving distance was 18cm, the infusion rate was 5mL / h, the slide table moving speed was 27cm / min, and the receiving roller speed was 27r / min. Modified fibers were obtained by electrospinning and transferred to a tube furnace. After nitrogen protection was introduced into the tube furnace, the temperature was raised to 650℃ at a heating rate of 5℃ / min. The nitrogen was then turned off, and oxygen was introduced at a flow rate of 2L / min. After holding at this temperature for 2h, the oxygen was turned off, and nitrogen was introduced again. The temperature was raised to 1300℃ at a heating rate of 6℃ / min. After holding at this temperature for 2h, the temperature was naturally cooled to 135℃. The nitrogen was then turned off, and water vapor was introduced at a flow rate of 2L / min. After holding at this temperature for 2h, porous fibers were obtained.

[0131] Step IV: Preparation of composite fiber precursor

[0132] Modified fibers were impregnated in phosphate slurry and subjected to a two-impregnation and two-roll process with a bath ratio of 1:21 and an impregnation rate of 110%. The material was then transferred to an oven at 270°C and cured to constant weight in a nitrogen atmosphere. After natural cooling to room temperature, the process was repeated four times to obtain the composite fiber precursor.

[0133] Step V: Preparation of composite fibers

[0134] Weigh 700.0g of the composite fiber precursor and 2700.0mL of N,N-dimethylformamide and add them to the reaction vessel. After the temperature of the reaction vessel is raised to 50℃, add 240.0g of the modified curing agent prepared in Example 3 to the reaction vessel and adjust the pH of the reaction system to 9 using saturated sodium hydroxide solution. After stirring for 36min, the reaction is completed. After the temperature of the reaction vessel is lowered to room temperature, filter the reaction liquid and collect the filter cake. Transfer the filter cake to a drying oven at 70℃ and vacuum dry it to constant weight to obtain the composite fiber.

[0135] Example 10

[0136] This embodiment provides a method for preparing a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant material for a radome, including the following steps:

[0137] Weigh out 7000.0g of the modified polytetrafluoroethylene prepared in Example 4, 1000.0g of the composite fiber prepared in Example 7, 500.0g of the modified curing agent prepared in Example 1, 50.0g of benzophenone, 500.0g of maleic anhydride, 50.0g of tricyclohexylphosphine, 500.0g of mica powder and 300.0g of triphenyl phosphate and add them to a melting tank at 250℃ and stir for 20min. Transfer the melt to a vacuum sintering furnace and heat it to 350℃ at a heating rate of 8℃ / min under a nitrogen atmosphere. After sintering at a constant temperature for 2h, cool it to 120℃ at a cooling rate of 4℃ / min and allow it to cool naturally to room temperature to obtain the radome material.

[0138] Example 11

[0139] This embodiment provides a method for preparing a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant material for a radome, including the following steps:

[0140] Weigh out 8000.0g of the modified polytetrafluoroethylene prepared in Example 5, 2000.0g of the composite fiber prepared in Example 8, 1000.0g of the modified curing agent prepared in Example 2, 200.0g of benzophenone, 1000.0g of maleic anhydride, 200.0g of tricyclohexylphosphine, 1000.0g of mica powder and 500.0g of triphenyl phosphate and add them to a melting tank at 280℃ and stir for 30min. Transfer the melt to a vacuum sintering furnace and heat it to 400℃ at a rate of 10℃ / min under a nitrogen atmosphere. After sintering at a constant temperature for 4h, cool it to 150℃ at a rate of 5℃ / min and allow it to cool naturally to room temperature to obtain the radome material.

[0141] Example 12

[0142] This embodiment provides a method for preparing a fiber-reinforced, high-transparency, weather-resistant, and impact-resistant material for a radome, including the following steps:

[0143] Weigh out 7500.0g of the modified polytetrafluoroethylene prepared in Example 6, 1500.0g of the composite fiber prepared in Example 9, 800.0g of the modified curing agent prepared in Example 3, 100.0g of benzophenone, 800.0g of maleic anhydride, 100.0g of tricyclohexylphosphine, 800.0g of mica powder and 400.0g of triphenyl phosphate and add them to a melting tank at 270℃ and stir for 30min. Transfer the melt to a vacuum sintering furnace and heat it to 400℃ at a rate of 10℃ / min under a nitrogen atmosphere. After sintering at a constant temperature for 3h, cool it to 120℃ at a rate of 4℃ / min and allow it to cool naturally to room temperature to obtain the radome material.

[0144] Comparative Example 1

[0145] The difference between this comparative example and Example 12 is that steps ② and ③ are omitted in the preparation process of the modified polytetrafluoroethylene used.

[0146] Comparative Example 2

[0147] The difference between this comparative example and Example 12 is that steps I and IV are omitted in the preparation process of the composite fiber used.

[0148] Comparative Example 3

[0149] The difference between this comparative example and Example 12 is that, in the preparation process of the composite fiber, step V is omitted, and an equal amount of composite fiber precursor is used to replace the composite fiber.

[0150] Comparative Example 4

[0151] The difference between this comparative example and Example 12 is that the modified curing agent was omitted.

[0152] Performance testing:

[0153] The wave transmission performance of the radome materials prepared in Examples 10-12 and Comparative Examples 1-3 was determined in accordance with the standard GB / T 5597-1999 "Test Method for Microwave Complex Permittivity of Solid Dielectrics".

[0154] The impact resistance of the radome materials prepared in Examples 10-12 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams".

[0155] The vertical flammability ratings of the radome materials prepared in Examples 10-12 and Comparative Examples 1-3 were tested in accordance with the standard GB / T 2408-2021 "Determination of the flammability of plastics - Horizontal and Vertical Methods".

[0156] The volumetric wear of the radome materials prepared in Examples 10-12 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 9867-2008 "Determination of abrasion resistance of vulcanized rubber or thermoplastic rubber (rotary roller abrasion tester method)". The specific data are shown in Table 1.

[0157] The radome materials prepared in Examples 10-12 and Comparative Examples 1-3 were subjected to ultraviolet irradiation treatment according to standard GB / T 16422.3-2022 "Laboratory Light Source Exposure Test Methods for Plastics - Part 3: Fluorescent Ultraviolet Lamps". The wave transmission performance of the radome materials was determined according to standard GB / T 5597-1999, the cantilever beam impact strength of the radome materials was determined according to standard GB / T 1843-2008, and the volumetric wear of the radome materials was determined according to standard GB / T 9867-2008. The specific data are shown in Table 2.

[0158] Table 1 - Performance Test Data for Each Sample

[0159] Project Group Example 10 Example 11 Example 12 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 3 Dielectric constant 2.8 2.6 2.5 3.1 4.2 3.2 3.0 Dielectric loss tangent 0.0003 0.0002 0.0002 0.005 0.008 0.003 0.005 <![CDATA[Izod impact strength / kJ·m -2 > 51.3 53.2 54.1 42.1 43.2 43.5 35.2 <![CDATA[Volume wear amount / mm 3 > 28.9 27.5 27.1 36.5 33.1 34.6 45.6 Vertical flammability rating V-0 V-0 V-0 V-1 V-1 V-0 V-0

[0160] Table 2 - Performance test data of each sample after UV aging

[0161] Project Group Example 10 Example 11 Example 12 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 3 Dielectric constant 2.9 2.7 2.7 4.8 4.5 4.4 4.2 Dielectric loss tangent 0.0004 0.0003 0.0003 0.018 0.010 0.008 0.013 <![CDATA[Izod impact strenth / kJ·m -2 > 50.2 51.6 52.3 33.5 39.4 41.5 28.4 <![CDATA[Volume wear amount / mm 3 > 29.4 28.6 28.1 44.5 36.1 38.5 41.6 Vertical flammability rating V-0 V-0 V-0 V-1 V-1 V-0 V-0

[0162] Data Analysis:

[0163] A comparative analysis of the data in Tables 1-2 reveals that the radome material prepared in this invention has a dielectric constant of 2.5, a dielectric loss tangent of 0.0002, and a cantilever beam impact strength of 53.2 kJ·m. -2 The volumetric wear was 27.1 mm. 3Simultaneously, the vertical combustion rating is V-0, and the dielectric constant of the radome material after ultraviolet irradiation is 2.5, the dielectric loss tangent is 0.0003, and the cantilever beam impact strength is 52.3 kJ·m. -2 The volumetric wear amount is 28.1 mm. 3 At the same time, its vertical combustion rating is V-0;

[0164] This invention describes a modified curing agent with siloxane and double bond structures in its side chains. This agent modifies the modified fibers through siloxane hydrolysis, thereby enhancing the stability and compatibility with organic materials. Furthermore, it utilizes free radical polymerization to modify the activated grafted polyvinylidene fluoride segments. The siloxane structure on the surface synergistically enhances the material's weather resistance with the silica component in the modified fibers. Simultaneously, the synergistic flame-retardant effect of both the siloxane and silica components, along with the alumina and phosphate within the modified fibers, further enhances the material's flame-retardant properties. During high-temperature processing, the oxazine ring in the modified curing agent undergoes ring-opening polymerization, tightly binding the modified polytetrafluoroethylene and the composite fibers, thus significantly enhancing the material's impact resistance.

[0165] This invention describes the process of preparing modified polytetrafluoroethylene (PTFE) fibers. First, a porous fiber is obtained through hydrolysis, electrospinning, and high-temperature calcination. In addition to phosphate modification enhancing the fiber's wave transmission performance, the flame retardant properties are enhanced through a composite flame retardant effect. After modification with a curing agent and coating with highly hydrophobic PTFE, the modified fiber isolates moisture, significantly improving the stability of the phosphate structure. Furthermore, the inherent low-loss characteristics of PTFE, when filled with silica fiber, form a gradient dielectric structure, reducing electromagnetic wave reflection at different media interfaces and increasing wave transmittance. The phosphate layer forms a uniformly distributed low-loss phase within the material, improving wave transmission uniformity and enhancing material stability. Through the synergistic effect of these three factors, the wave transmission performance of the material is enhanced.

[0166] This invention describes a modified curing agent with a long-chain structure. After surface modification of the grafted polytetrafluoroethylene (PTFE) and composite fiber precursors through its side-chain structure, modified PTFE and composite fibers are obtained. During the sintering process with auxiliary materials, the oxazine rings in the modified curing agent undergo ring-opening polymerization, improving the material's curing efficiency, thus yielding an antenna radome material. The siloxane structure within the material enhances its weather resistance, while its synergistic effect with the phosphate structure, along with the silica protective layer and carbonization-promoting effect generated during combustion, significantly enhances the material's flame-retardant effect. Furthermore, the inherent low-loss characteristics of PTFE and the synergistic effect of the composite fibers significantly improve the material's wave transmission performance.

[0167] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for a radome, characterized in that, It comprises the following raw materials in parts by weight: 70-80 parts modified polytetrafluoroethylene, 10-20 parts composite fiber, 5-10 parts modified curing agent and 14-29 parts auxiliary materials; The auxiliary materials include the following materials in parts by weight: 0.5-2 parts UV stabilizer, 5-10 parts toughening agent, 0.5-2 parts antioxidant, 5-10 parts filler and 3-5 parts flame retardant.

2. The fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for a radome according to claim 1, characterized in that, The preparation method of the modified polytetrafluoroethylene includes the following steps: A1. Add polytetrafluoroethylene powder to a radio frequency plasma reactor, and after plasma treatment for 5-10 minutes, let it stand in air for 10-15 minutes to obtain activated polytetrafluoroethylene. A2. Allyl glycidyl ether and N,N-dimethylformamide were added to the reaction vessel and stirred. After the temperature of the reaction vessel was raised to 40-60℃, activated polytetrafluoroethylene and triethylamine were added to the reaction vessel. After stirring for 30-40 minutes, the grafted polytetrafluoroethylene was obtained through post-treatment. A3. Add the modified curing agent and N,N-dimethylformamide to the reactor and stir. After the reactor temperature is raised to 60-80℃, add grafted polytetrafluoroethylene and azobisisobutyronitrile to the reactor. After stirring for 1-2 hours, the modified polytetrafluoroethylene is obtained through post-treatment.

3. The fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for a radome according to claim 2, characterized in that, In step A2, the ratio of allyl glycidyl ether, N,N-dimethylformamide, activated polytetrafluoroethylene, and triethylamine is 2-3g:36-40mL:8-10g:0.3-0.6g; in step A3, the ratio of modified curing agent, N,N-dimethylformamide, grafted polytetrafluoroethylene, and azobisisobutyronitrile is 3-4g:40-45mL:9-12g:0.2-0.4g.

4. The fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for a radome according to claim 1, characterized in that, The method for preparing the composite fiber includes the following steps: B1. Add aluminum chloride, tetraethyl silicate and deionized water to a hydrothermal reactor. Stir at room temperature for 10-15 min, then add aluminum triisopropoxy and polyvinyl alcohol. Raise the temperature of the hydrothermal reactor to 160-180℃ and keep it at that temperature for 8-12 h to obtain a composite gel. B2. The composite gel is added to an electrospinning machine, and modified fibers are obtained by electrospinning. The modified fibers are then post-treated to obtain porous fibers. B3. The modified fibers are impregnated and modified in phosphate slurry for 3-5 times to obtain composite fiber precursors; B4. Add the composite fiber precursor and N,N-dimethylformamide to the reactor and stir. After the reactor temperature is raised to 40-60℃, continue to add the modified curing agent to the reactor and adjust the pH of the reaction system to 8-10 using saturated sodium hydroxide solution. After stirring for 30-40 minutes, the composite fiber is obtained through post-treatment.

5. The fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for a radome according to claim 4, characterized in that, In step B1, the ratio of aluminum chloride, tetraethyl silicate, deionized water, aluminum triisopropoxy, and polyvinyl alcohol is 12-15g:8-10g:40-50mL:9-12g:1-2g; in step B4, the ratio of composite fiber precursor, N,N-dimethylformamide, and modified curing agent is 6-8g:24-30mL:2-3g.

6. The fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for a radome according to claim 5, characterized in that, The method for preparing the phosphate slurry includes the following steps: adding phosphoric acid solution and aluminum hydroxide into a reaction vessel, raising the temperature of the reaction vessel to 60-80℃, stirring and keeping it warm until the solution is clear, adding chromium oxide and hydrogen peroxide into the reaction vessel, stirring and keeping it warm for 2-3 hours to obtain the phosphate slurry.

7. The fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for a radome according to claim 6, characterized in that, The concentration of the phosphoric acid solution is 40-60 wt%, and the ratio of phosphoric acid solution, aluminum hydroxide, chromium oxide and hydrogen peroxide is 40-60 mL: 2.4-3.0 g: 1.4-1.6 g: 0.4-0.6 g.

8. The fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for a radome according to claim 1, characterized in that, The preparation method of the modified curing agent includes the following steps: C1. Add glycidyltrimethoxysilane, 1,3-diamino-2-hydroxypropane, triethylamine and N,N-dimethylformamide to a reaction vessel, raise the temperature of the reaction vessel to 40-60℃, and keep the reaction at this temperature for 30-40 min to obtain modified siloxane. C2. Add the modified siloxane and tetrahydrofuran to the reflux apparatus. After purging with nitrogen for protection, lower the temperature of the reflux apparatus to 0-3℃. Continue to add formaldehyde solution to the reactor. After stirring at the temperature for 30-40 minutes, add 6-methyljuncusiol solution dropwise to the reactor. After the addition is complete, raise the temperature of the reflux apparatus back to reflux and keep the reaction at the temperature for 18-20 hours. The modified curing agent is then obtained through post-treatment.

9. The fiber-reinforced, high-transparency, weather-resistant and impact-resistant material for a radome according to claim 8, characterized in that, In step C1, the ratio of glycidyltrimethoxysilane, 1,3-diamino-2-hydroxypropane, triethylamine, and N,N-dimethylformamide is 4-6 g: 2-3 g: 0.2-0.5 g: 25-30 mL; in step C2, the ratio of modified siloxane, tetrahydrofuran, formaldehyde solution, and 6-methyljuncusiol solution is 8.1-9.9 g: 30-32 mL: 20-24 mL: 40-50 mL.

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