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] The present invention relates to the technical field of wave-transparent materials, and particularly relates to a weather-resistant and impact-resistant material for fiber-reinforced high-wave-transparent radomes. Background Art

[0002] The development of high-wave-transparent radome materials has evolved from glass fiber-reinforced resins to high-performance polymer composites. Early glass fiber radomes had high dielectric constants and average weather resistance, resulting in large losses in high-frequency applications. With the development of radar, 5G communication, and aerospace technologies, the demand for materials with low dielectric, low loss, high weather resistance, and impact resistance 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 the wave transmission rate and weather resistance, and through technologies such as nano-SiO2, BN modification, ultraviolet stabilizers, and fluorocarbon coatings, the long-term stability and environmental adaptability of the materials have been further improved, making them widely used in high-end fields such as aerospace, 5G millimeter-wave radar, and stealth radomes.

[0003] The prior art CN104059601B discloses a synthesis method of a phosphoric acid-based wave-transparent material. Using an inorganic adhesive as the base material and an organic wave-transparent material as the template agent, after mixing evenly, it is added to a mold and left standing for 24 h, cured at 60 - 80 °C, and flattened once every 1 h during the curing process. After curing, it is calcined at 600 - 800 °C to obtain the phosphoric acid-based wave-transparent material. The prepared phosphoric acid-based wave-transparent material has excellent high-temperature resistance and wave transmission performance.

[0004] However, the above patent content only obtains the phosphoric acid-based wave-transparent material by using an organic wave-transparent material as the template agent for curing and calcination. However, the prepared phosphoric acid-based wave-transparent material has a single structure, resulting in poor impact toughness of the material, and is easily affected by humidity and temperature changes, causing hydrolysis or swelling, resulting in deterioration of the wave transmission performance, thereby leading to the need for further improvement in the impact resistance and wave transmission performance of the material.

[0005] In view of the technical defects in this regard, a solution is now proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a weather-resistant and impact-resistant material for fiber-reinforced high-wave-transparent radomes, aiming to solve the technical problem that the wave transmission performance and impact resistance of wave-transparent materials in the prior art need to be further improved.

[0007] The purpose of the present invention can be achieved through the following technical solutions: A weather-resistant and impact-resistant material for fiber-reinforced high-wave-transparent radomes, comprising the following raw material components by weight: 70 - 80 parts of modified polytetrafluoroethylene, 10 - 20 parts of composite fibers, 5 - 10 parts of modified curing agent, and 14 - 29 parts of auxiliary materials;

[0008] Among them, the auxiliary materials include the following materials by weight: 0.5 - 2 parts of ultraviolet absorber, 5 - 10 parts of toughening agent, 0.5 - 2 parts of antioxidant, 5 - 10 parts of filler, and 3 - 5 parts of flame retardant.

[0009] Furthermore, the ultraviolet absorber 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 talcum powder and mica powder; the flame retardant is one or more of decabromodiphenyl ether, melamine, and triphenyl phosphate.

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

[0011] A1. Add polytetrafluoroethylene powder into a radio frequency plasma reactor. After plasma treatment, let it stand in the air for 10 - 15 min to obtain activated polytetrafluoroethylene.

[0012] A2. Add allyl glycidyl ether and N,N - dimethylformamide into a reaction kettle and stir. After the temperature of the reaction kettle rises to 40 - 60 °C, add activated polytetrafluoroethylene and triethylamine into the reaction kettle. After keeping the temperature and stirring for 30 - 40 min, conduct post - treatment to obtain grafted polytetrafluoroethylene.

[0013] A3. Add modified curing agent and N,N - dimethylformamide into a reaction kettle and stir. After the temperature of the reaction kettle rises to 60 - 80 °C, add grafted polytetrafluoroethylene and azobisisobutyronitrile into the reaction kettle. After keeping the temperature and stirring for 1 - 2 h, conduct post - treatment to obtain modified polytetrafluoroethylene.

[0014] The reaction principle for preparing the modified polytetrafluoroethylene 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 the polytetrafluoroethylene powder. Under alkaline conditions, allyl glycidyl ether undergoes ring - opening to generate free radicals, which react with the activated functional groups on the activated polytetrafluoroethylene to obtain grafted polytetrafluoroethylene with a double - bond structure. Finally, under the catalysis of a free - radical initiator and high temperature, the double - bond structure on the grafted polytetrafluoroethylene undergoes a free - radical polymerization reaction with the double - bond on the side chain of the modified curing agent, and finally the modified polytetrafluoroethylene is prepared.

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

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

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

[0018] Further, the preparation method of the composite fiber includes the following steps:

[0019] B1. Add aluminum chloride, tetraethyl orthosilicate and deionized water into a hydrothermal reaction kettle. After stirring at room temperature for 10-15 min, continue to add aluminum triisopropoxide and polyvinyl alcohol. Raise the temperature of the hydrothermal reaction kettle to 160-180 °C and keep stirring for 8-12 h to obtain a composite gel;

[0020] B2. Add the composite gel into an electrospinning machine, and obtain modified fibers by electrospinning. Post-treat the modified fibers to obtain porous fibers;

[0021] B3. Immerse and modify the modified fibers in a phosphate slurry for 3-5 times to obtain a composite fiber precursor;

[0022] B4. Add the composite fiber precursor and N,N-dimethylformamide into a reaction kettle and stir. After the temperature of the reaction kettle rises to 40-60 °C, continue to add the modified curing agent into the reaction kettle and use saturated sodium hydroxide solution to adjust the pH of the reaction system to 8-10. Keep stirring for 30-40 min and then post-treat to obtain the composite fiber.

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

[0024] Further, in step B1, the dosage ratio of aluminum chloride, tetraethyl orthosilicate, deionized water, aluminum triisopropoxide and polyvinyl alcohol is 12 - 15 g : 8 - 10 g : 40 - 50 mL : 9 - 12 g : 1 - 2 g;

[0025] Further, in step B2, the process requirements of electrospinning are as follows: temperature 20 - 25 °C, humidity 25 - 35%, applied voltage 18 - 21 kV, receiving distance 18 - 20 cm, perfusion speed 4 - 6 mL / h, sliding table moving speed 24 - 30 cm / min, receiving roller rotation speed 24 - 30 r / min; The post-treatment operation is as follows: transfer the modified fibers to a tube furnace. After introducing nitrogen protection into the tube furnace, the tube furnace is heated to 600 - 650 °C at a heating rate of 5 - 6 °C / min, nitrogen is cut off, oxygen is introduced at a flow rate of 1 - 2 L / min, after heat preservation treatment for 1 - 2 h, oxygen is cut off, nitrogen is continuously introduced and then heated to 1250 - 1350 °C at a heating rate of 5 - 6 °C / min, after heat preservation treatment for 1 - 2 h, it is naturally cooled to 120 - 150 °C, nitrogen is cut off, steam is introduced at a flow rate of 1 - 2 L / min, and after heat preservation treatment for 1 - 2 h, porous fibers are obtained;

[0026] Further, in step B3, the padding modification operation is as follows: after the two-bath two-roll process, transfer the material to an oven at 150 - 180 °C, cure it to constant weight in a nitrogen atmosphere, and then naturally cool it to room temperature to obtain a composite fiber precursor, where the bath ratio is 1:20 - 24 and the padding rate is 100 - 110%;

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

[0028] Further, the preparation method of the phosphate slurry includes the following steps: add phosphoric acid solution and aluminum hydroxide into a reaction kettle, raise the temperature of the reaction kettle to 60 - 80 °C, keep stirring until the solution is clear, then add chromium oxide and hydrogen peroxide into the reaction kettle, and keep stirring for 2 - 3 h to obtain the phosphate slurry.

[0029] The preparation principle of the phosphate slurry is: phosphoric acid reacts with aluminum oxide to prepare a phosphate structure, and under acidic conditions, hydrogen peroxide converts hexavalent chromium into trivalent chromium ions, which are complexed with phosphates to finally prepare the phosphate slurry.

[0030] Further, the concentration of the phosphoric acid solution is 40-60 wt%, and the dosage ratio of the 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] Further, the preparation method of the modified curing agent includes the following steps:

[0032] C1. Add epoxypropyltrimethoxysilane, 1,3-diamino-2-hydroxypropane, triethylamine and N,N-dimethylformamide into a reaction kettle, raise the temperature of the reaction kettle to 40-60 °C, keep the temperature for reaction for 30-40 min to obtain a modified siloxane;

[0033] C2. Add the modified siloxane and tetrahydrofuran into a reflux device, after introducing nitrogen protection, lower the temperature of the reflux device to 0-3 °C, continue to add formaldehyde solution into the reaction kettle, after keeping the temperature and stirring for 30-40 min, dropwise add 6-methyljuncusin solution into the reaction kettle. After the dropping is completed, raise the temperature of the reflux device to reflux, keep the temperature for reaction for 18-20 h, and perform post-treatment to obtain the modified curing agent.

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

[0035]

[0036] In the formula:

[0037] The reaction principle for preparing the modified curing agent is: under alkaline conditions, the epoxy group on epoxypropyltrimethoxysilane opens the ring to generate free radicals, which react with the hydroxyl group on 1,3-diamino-2-hydroxypropane to prepare the modified siloxane. Among them, the mass spectrometry analysis data of the modified siloxane are: m / z: 181.4 (100.0%), 181.9 (10.8%), 182.8 (4.8%); and under the protection of nitrogen, the diamino group on the modified siloxane, formaldehyde and the hydroxyl group on 6-methyljuncusin undergo a cyclization reaction to form a modified curing agent with a polyoxazine structure.

[0038] Further, in step C1, the dosage ratio of epoxypropyltrimethoxysilane, 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, cool the reaction kettle to room temperature, add the reaction solution into a rotary evaporator with a water bath temperature of 80-100 °C, and perform vacuum distillation until no liquid is collected to obtain the modified siloxane;

[0039] Further, in step C2, the dosage ratio of the modified siloxane, tetrahydrofuran, formaldehyde solution, and 6-methyljuncus diol solution is 8.1 - 9.9 g : 30 - 32 mL : 20 - 24 mL : 40 - 50 mL. Among them, the formaldehyde solution is obtained by mixing formaldehyde gas and tetrahydrofuran in a dosage ratio of 3.6 - 4.4 g : 20 - 24 mL, and the 6-methyljuncus diol solution is obtained by mixing 6-methyljuncus diol and tetrahydrofuran in a dosage ratio of 9.9 - 12.1 g : 40 - 50 mL. The post-treatment includes: after the reaction is completed, the reaction kettle is cooled to room temperature, and the reaction solution is added into a rotary evaporator with a water bath temperature of 80 - 100 °C, and vacuum distilled until no liquid is drawn out to obtain the modified curing agent.

[0040] Further, a preparation method of a weather-resistant and impact-resistant material for a fiber-reinforced high-transmission radome is as follows: Add modified polytetrafluoroethylene, composite fiber, modified curing agent, ultraviolet absorber, toughening agent, antioxidant, filler, and flame retardant into a melting tank at a temperature of 250 - 280 °C and stir for 20 - 30 min. Transfer the melt to a vacuum sintering furnace and sinter to obtain the radome material.

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

[0042]

[0043] The reaction principle of high-temperature curing is: 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, so that it has partial positive charge. During the ring-opening curing process, the carbon-oxygen bond is first broken into an oxygen anion and a carbon cation, and the carbon cation intermediate randomly attacks the ortho-carbon atom of oxygen on the benzene ring to initiate polymerization. Through the polymerization reaction of the oxazine rings on the modified curing agent, composite fiber, and modified polytetrafluoroethylene, the materials are tightly combined together, and finally the radome material is prepared.

[0044] Further, the sintering operation is as follows: Under the atmosphere of nitrogen, the temperature of the sintering furnace is raised to 350 - 400 °C at a heating rate of 8 - 10 °C / min, kept at a constant temperature for 2 - 4 h, then cooled to 120 - 150 °C at a cooling rate of 4 - 5 °C / min, and naturally cooled to room temperature to obtain the radome material.

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

[0046] 1. The present invention prepares a modified curing agent with a long-chain structure. After the side-chain structure modifies the surface of grafted polytetrafluoroethylene and composite fiber precursors, during the process of mixing and sintering the modified polytetrafluoroethylene and composite fibers with auxiliary materials, the oxazine ring structure in the modified curing agent component undergoes ring-opening polymerization to improve the curing efficiency of the material, thereby obtaining a radome material. The siloxane structure inside the material enhances the weather resistance of the material. At the same time, in coordination with the phosphate structure, the silica protection layer and carbonization-promoting effect generated during combustion cooperate synergistically to significantly enhance the flame retardancy of the material. Moreover, the inherent low-loss characteristics of polytetrafluoroethylene and the composite fibers cooperate to significantly improve the wave-transmitting performance of the material.

[0047] 2. The present invention also prepares a modified curing agent with a siloxane and double-bond structure in the side chain. It modifies the modified fibers through the hydrolysis of the siloxane structure, thereby enhancing the stability of the modified fibers and their compatibility with organic materials. And it modifies the polyvinylidene fluoride chain segments after activation grafting by using free radical polymerization reaction. The siloxane structure on its surface and the silica component in the modified fibers cooperate synergistically to significantly enhance the weather resistance of the material. At the same time, the two and the alumina and phosphate inside the modified fibers further enhance the flame retardancy of the material through a synergistic flame retardancy effect. And during the high-temperature processing, the oxazine ring in the modified curing agent component undergoes ring-opening polymerization, making the modified polytetrafluoroethylene and composite fibers tightly combined, thereby significantly enhancing the impact resistance of the material.

[0048] 3. During the process of preparing modified fibers with modified polytetrafluoroethylene in the present invention, first, a porous fiber is obtained through hydrolysis, electrospinning, and high-temperature calcination. Besides enhancing the wave-transmitting performance of the fiber through phosphate modification, the flame retardancy of the material is enhanced through a component composite flame retardancy effect. After the modified fibers are modified by the modified curing agent and coated with highly hydrophobic modified polytetrafluoroethylene, water is isolated, thereby significantly improving the stability of the phosphate structure. Moreover, due to the inherent low-loss characteristics of polytetrafluoroethylene, a gradient dielectric structure is formed after filling the silica fiber structure, thereby reducing the reflection of electromagnetic waves at the interfaces of different media, increasing the wave-transmission rate, providing a low-loss phase with uniform distribution of phosphate inside the material, improving the wave-transmission uniformity, and at the same time enhancing the material stability. Through the synergistic cooperation of the three, the wave-transmitting performance of the material is enhanced. Detailed implementation manners

[0049] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

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

[0051] Example 1

[0052] This example is used to provide a preparation method of a modified curing agent for a weather-resistant and impact-resistant material for a fiber-reinforced high-wave-transmission radome, including the following steps:

[0053] Step (1), preparing modified siloxane

[0054] Weigh: 400.0 g of epoxypropyltrimethoxysilane, 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 the reaction kettle. The temperature of the reaction kettle is raised to 40 °C, and the reaction is carried out for 30 minutes while maintaining the temperature. After the reaction is completed, the reaction kettle is cooled to room temperature. The reaction solution is added to a rotary evaporator with a water bath temperature of 80 °C, and vacuum distillation is carried out until no liquid is collected, obtaining modified siloxane.

[0055] Step (2), preparing modified curing agent

[0056] Weigh: 360.0 g of formaldehyde gas and 2000.0 mL of tetrahydrofuran are mixed to obtain a formaldehyde solution;

[0057] Weigh: 990.0 g of 6-methyljuncusol and 4000.0 mL of tetrahydrofuran are mixed to obtain a 6-methyljuncusol solution;

[0058] Weigh: 810.0 g of modified siloxane and 3000.0 mL of tetrahydrofuran are added to a reflux device. After introducing nitrogen protection, the temperature of the reflux device is reduced to 0 °C. Then, 2000.0 mL of the formaldehyde solution is continuously added to the reaction kettle. After maintaining stirring for 30 minutes, 4000.0 mL of the 6-methyljuncusol solution is added dropwise to the reaction kettle. After the addition is completed, the temperature of the reflux device rises to reflux, and the reaction is carried out for 18 hours while maintaining the temperature. After the reaction is completed, the reaction kettle is cooled to room temperature. The reaction solution is added to a rotary evaporator with a water bath temperature of 80 °C, and vacuum distillation is carried out until no liquid is collected, obtaining modified curing agent.

[0059] Example 2

[0060] This example is used to provide a preparation method of a modified curing agent for a weather-resistant and impact-resistant material for a fiber-reinforced high-wave-transmission radome, including the following steps:

[0061] Step (1), preparing modified siloxane

[0062] Weigh: 600.0 g of glycidoxytrimethoxysilane, 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 kettle. Raise the temperature of the reaction kettle to 60 °C and keep the temperature for reaction for 40 min. After the reaction is completed, cool the reaction kettle to room temperature. Add the reaction solution to a rotary evaporator with a water bath temperature of 100 °C and distill under reduced pressure until no liquid is collected, to obtain the modified siloxane.

[0063] Step (2), preparing the modified curing agent

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

[0065] Weigh: 1210.0 g of 6-methyljuncus diol and 5000.0 mL of tetrahydrofuran and mix them to obtain a 6-methyljuncus diol solution;

[0066] Weigh: 990.0 g of the modified siloxane and 3200.0 mL of tetrahydrofuran and add them to a reflux device. After introducing nitrogen protection, lower the temperature of the reflux device to 0 °C. Continue to add 2400.0 mL of the formaldehyde solution to the reaction kettle. After keeping the temperature and stirring for 40 min, gradually add 5000.0 mL of the 6-methyljuncus diol solution dropwise to the reaction kettle. After the dropping is completed, raise the temperature of the reflux device to reflux and keep the temperature for reaction for 20 h. After the reaction is completed, cool the reaction kettle to room temperature. Add the reaction solution to a rotary evaporator with a water bath temperature of 100 °C and distill under reduced pressure until no liquid is collected, to obtain the modified curing agent.

[0067] Example 3

[0068] This example is used to provide a preparation method of a modified curing agent for a weather-resistant and impact-resistant material for a fiber-reinforced high-transmission radome, including the following steps:

[0069] Step (1), preparing the modified siloxane

[0070] Weigh: 500.0 g of glycidoxytrimethoxysilane, 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 kettle. Raise the temperature of the reaction kettle to 50 °C and keep the temperature for reaction for 36 min. After the reaction is completed, cool the reaction kettle to room temperature. Add the reaction solution to a rotary evaporator with a water bath temperature of 90 °C and distill under reduced pressure until no liquid is collected, to obtain the modified siloxane.

[0071] Step (2), preparing the modified curing agent

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

[0073] Weigh: Mix 1100.0 g of 6-methyljuncusol and 4500.0 mL of tetrahydrofuran to obtain a 6-methyljuncusol solution;

[0074] Weigh: Add 900.0 g of modified silicone and 3200.0 mL of tetrahydrofuran to a reflux device. After purging with nitrogen, lower the temperature of the reflux device to 1 °C, then continue to add 2100.0 mL of formaldehyde solution to the reaction kettle. After maintaining the temperature and stirring for 36 min, gradually add 4500.0 mL of the 6-methyljuncusol solution dropwise to the reaction kettle. After the addition is complete, raise the temperature of the reflux device to reflux, maintain the reaction for 18 h. After the reaction is completed, cool the reaction kettle to room temperature, add the reaction solution to a rotary evaporator with a water bath temperature of 90 °C, and distill under reduced pressure until no more liquid is collected to obtain a modified curing agent.

[0075] Example 4

[0076] This example is used to provide a preparation method of modified polytetrafluoroethylene for a weather-resistant and impact-resistant material for a fiber-reinforced high-transmission radome, including the following steps:

[0077] Step ①, prepare activated polytetrafluoroethylene

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

[0079] Step ②, prepare grafted polytetrafluoroethylene

[0080] Weigh: Add 200.0 g of allyl glycidyl ether and 3600.0 mL of N,N-dimethylformamide to a reaction kettle and stir. After raising the temperature of the reaction kettle to 40 °C, add 800.0 g of activated polytetrafluoroethylene and 30.0 g of triethylamine to the reaction kettle. After maintaining the temperature and stirring for 30 min, after the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, filter the reaction solution to collect the filter cake, and transfer the filter cake to a drying oven at 60 °C for vacuum drying to constant weight to obtain grafted polytetrafluoroethylene.

[0081] Step ③, prepare modified polytetrafluoroethylene

[0082] Weigh: 300.0 g of the modified curing agent prepared in Example 1 and 4000.0 mL of N,N-dimethylformamide were added to a reaction kettle and stirred. After the temperature of the reaction kettle was raised to 60 °C, 900.0 g of grafted polytetrafluoroethylene and 20.0 g of azobisisobutyronitrile were added to the reaction kettle. After keeping the temperature and stirring for 1 h, after the reaction was completed, when the temperature of the reaction kettle was lowered to room temperature, the reaction solution was filtered to collect the filter cake. The filter cake was transferred to a drying oven at 60 °C and vacuum dried to constant weight to obtain modified polytetrafluoroethylene.

[0083] Example 5

[0084] This example is used to provide a preparation method of modified polytetrafluoroethylene for a weather-resistant and impact-resistant material for a fiber-reinforced high-transmission radome, including the following steps:

[0085] Step ①, prepare activated polytetrafluoroethylene

[0086] Weigh: 1200.0 g of polytetrafluoroethylene powder was added to a radio frequency plasma reactor. The atmosphere of the radio frequency plasma reactor was argon, the radio frequency power was 13.64 MHz, the fixed discharge pressure was 70 Pa, and the discharge power was 60 W. After plasma treatment, it was left standing in the air for 15 min to obtain activated polytetrafluoroethylene.

[0087] Step ②, prepare grafted polytetrafluoroethylene

[0088] Weigh: 300.0 g of allyl glycidyl ether and 4000.0 mL of N,N-dimethylformamide were added to a reaction kettle and stirred. After the temperature of the reaction kettle was raised to 60 °C, 1000.0 g of activated polytetrafluoroethylene and 60.0 g of triethylamine were added to the reaction kettle. After keeping the temperature and stirring for 40 min, after the reaction was completed, when the temperature of the reaction kettle was lowered to room temperature, the reaction solution was filtered to collect the filter cake. The filter cake was transferred to a drying oven at 80 °C and vacuum dried to constant weight to obtain grafted polytetrafluoroethylene.

[0089] Step ③, prepare modified polytetrafluoroethylene

[0090] Weigh: 400.0 g of the modified curing agent prepared in Example 2 and 4500.0 mL of N,N-dimethylformamide were added to a reaction kettle and stirred. After the temperature of the reaction kettle was raised to 80 °C, 1200.0 g of grafted polytetrafluoroethylene and 40.0 g of azobisisobutyronitrile were added to the reaction kettle. After keeping the temperature and stirring for 2 h, after the reaction was completed, when the temperature of the reaction kettle was lowered to room temperature, the reaction solution was filtered to collect the filter cake. The filter cake was transferred to a drying oven at 80 °C and vacuum dried to constant weight to obtain modified polytetrafluoroethylene.

[0091] Example 6

[0092] This example is used to provide a preparation method of modified polytetrafluoroethylene for a weather-resistant and impact-resistant material for a fiber-reinforced high-wave-transmission radome, including the following steps:

[0093] Step ①, prepare activated polytetrafluoroethylene

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

[0095] Step ②, prepare grafted polytetrafluoroethylene

[0096] Weigh: Add 250.0 g of allyl glycidyl ether and 3600.0 mL of N,N-dimethylformamide into a reaction kettle and stir. After the temperature of the reaction kettle rises to 50 °C, add 900.0 g of activated polytetrafluoroethylene and 45.0 g of triethylamine into the reaction kettle. After keeping warm and stirring for 36 min, after the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, filter the reaction solution to collect the filter cake, transfer the filter cake to a drying oven at 70 °C and vacuum dry it to constant weight to obtain grafted polytetrafluoroethylene.

[0097] Step ③, prepare modified polytetrafluoroethylene

[0098] Weigh: Add 360.0 g of the modified curing agent prepared in Example 3 and 4200.0 mL of N,N-dimethylformamide into a reaction kettle and stir. After the temperature of the reaction kettle rises to 70 °C, add 1000.0 g of grafted polytetrafluoroethylene and 30.0 g of azobisisobutyronitrile into the reaction kettle. After keeping warm and stirring for 2 h, after the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, filter the reaction solution to 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 example is used to provide a preparation method of composite fiber for a weather-resistant and impact-resistant material for a fiber-reinforced high-wave-transmission radome, including the following steps:

[0101] Step Ⅰ, prepare phosphate slurry

[0102] Weigh: Add 4000.0 mL of 40 wt% phosphoric acid solution and 240.0 g of aluminum hydroxide into a reaction kettle. Raise the temperature of the reaction kettle to 60 °C, keep warm and stir until the solution is clear, then add 140.0 g of chromium oxide and 40.0 g of hydrogen peroxide into the reaction kettle, and keep warm and stir for 2 h to obtain phosphate slurry.

[0103] Step Ⅱ, prepare composite gel

[0104] Weigh: 1200.0 g of aluminum chloride, 800.0 g of tetraethyl orthosilicate and 4000.0 mL of deionized water and add them to a hydrothermal reactor. After stirring at room temperature for 10 min, continue to add 900.0 g of aluminum triisopropoxide and 100.0 g of polyvinyl alcohol. Raise the temperature of the hydrothermal reactor to 160 °C, keep stirring for 8 h to obtain a composite gel.

[0105] Step III: Prepare porous fibers

[0106] Add the composite gel to an electrospinning machine. The temperature for electrospinning is 20 °C, the humidity is 25%, the applied voltage is 18 kV, the receiving distance is 18 cm, the perfusion rate is 4 mL / h, the sliding table moving speed is 24 cm / min, and the receiving roller rotation speed is 24 r / min. Modified fibers are obtained by electrospinning. Transfer the modified fibers to a tubular furnace. After introducing nitrogen for protection in the tubular furnace, the tubular furnace is heated to 600 °C at a heating rate of 5 °C / min. Disconnect the nitrogen, and introduce oxygen at a flow rate of 1 L / min. After heat preservation treatment for 1 h, disconnect the oxygen, continue to introduce nitrogen, and then heat to 1250 °C at a heating rate of 5 °C / min. After heat preservation treatment for 1 h, naturally cool to 120 °C, disconnect the nitrogen, and introduce water vapor at a flow rate of 1 L / min. After heat preservation treatment for 1 h, porous fibers are obtained.

[0107] Step IV: Prepare a composite fiber precursor

[0108] Immerse the modified fibers in a phosphate slurry, and through a two-dip two-roll process with a bath ratio of 1:20 and an impregnation rate of 100%. Then transfer the material to an oven at 250 °C and cure it to a constant weight in a nitrogen atmosphere. Repeat the operation 3 times to obtain a composite fiber precursor.

[0109] Step V: Prepare composite fibers

[0110] Weigh: 600.0 g of the composite fiber precursor and 2400.0 mL of N,N-dimethylformamide and add them to a reaction kettle for stirring. After the temperature of the reaction kettle rises to 40 °C, continue to add 200.0 g of the modified curing agent prepared in Example 1 to the reaction kettle and use saturated sodium hydroxide solution to adjust the pH of the reaction system to 8. After keeping stirring for 30 min, after the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, filter the reaction solution to collect the filter cake, transfer the filter cake to a drying oven at 60 °C and vacuum dry it to a constant weight to obtain composite fibers.

[0111] Example 8

[0112] This example is used to provide a preparation method of composite fibers for a weather-resistant and impact-resistant material for a fiber-reinforced high-transmission radome, including the following steps:

[0113] Step Ⅰ: Preparation of phosphate slurry

[0114] Weigh: 6000.0 mL of 60 wt% phosphoric acid solution and 300.0 g of aluminum hydroxide and add them to a reaction kettle. The temperature of the reaction kettle is raised to 80 °C. After keeping warm and stirring until the solution becomes clear, add 160.0 g of chromium oxide and 60.0 g of hydrogen peroxide to the reaction kettle, keep warm and stir for 3 h to obtain the phosphate slurry.

[0115] Step Ⅱ: Preparation of composite gel

[0116] Weigh: 1500.0 g of aluminum chloride, 1000.0 g of tetraethyl orthosilicate and 5000.0 mL of deionized water and add them to a hydrothermal reaction kettle. After stirring at room temperature for 15 min, continue to add 1200.0 g of aluminum triisopropoxide and 200.0 g of polyvinyl alcohol. The temperature of the hydrothermal reaction kettle is raised to 180 °C. Keep warm and stir for 12 h to obtain the composite gel.

[0117] Step Ⅲ: Preparation of porous fibers

[0118] Add the composite gel to an electrospinning machine. The temperature of electrospinning is 25 °C, the humidity is 35%, the applied voltage is 21 kV, the receiving distance is 20 cm, the perfusion speed is 6 mL / h, the sliding table moving speed is 30 cm / min, and the receiving roller rotation speed is 30 r / min. Modified fibers are obtained by electrospinning. Transfer the modified fibers to a tubular furnace. After introducing nitrogen for protection in the tubular furnace, the tubular furnace is heated to 650 °C at a heating rate of 6 °C / min, the nitrogen is disconnected, oxygen is introduced at a flow rate of 2 L / min, after heat preservation treatment for 2 h, the oxygen is disconnected, nitrogen is continuously introduced and then heated to 1350 °C at a heating rate of 6 °C / min, after heat preservation treatment for 2 h, it is naturally cooled to 150 °C, the nitrogen is disconnected, and steam is introduced at a flow rate of 2 L / min, after heat preservation treatment for 2 h, porous fibers are obtained.

[0119] Step Ⅳ: Preparation of composite fiber precursor

[0120] Immerse the modified fibers in the phosphate slurry, and through a two-dip two-roll process with a bath ratio of 1:24 and an impregnation rate of 110%, then transfer the material to an oven at 280 °C and cure it to a constant weight in a nitrogen atmosphere. Repeat the operation 5 times to obtain the composite fiber precursor.

[0121] Step Ⅴ: Preparation of composite fibers

[0122] Weigh: 800.0 g of the composite fiber precursor and 3000.0 mL of N,N-dimethylformamide and add them to a reaction kettle for stirring. After the temperature of the reaction kettle rises to 60 °C, continue to add 300.0 g of the modified curing agent prepared in Example 2 to the reaction kettle and use saturated sodium hydroxide solution to adjust the pH of the reaction system to 10. After keeping warm and stirring for 40 min, after the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, filter the reaction solution by suction to collect the filter cake, transfer the filter cake to a drying oven at 80 °C and vacuum dry it to constant weight to obtain the composite fiber.

[0123] Example 9

[0124] This example is used to provide a preparation method of composite fiber for a weather-resistant and impact-resistant material for a fiber-reinforced high-transmission radome, including the following steps:

[0125] Step I, prepare phosphate slurry

[0126] Weigh: 5000.0 mL of 50 wt% phosphoric acid solution and 270.0 g of aluminum hydroxide and add them to a reaction kettle. Raise the temperature of the reaction kettle to 70 °C, keep warm and stir until the solution is clear, then add 150.0 g of chromium oxide and 50.0 g of hydrogen peroxide to the reaction kettle, keep warm and stir for 3 h to obtain the phosphate slurry.

[0127] Step II, prepare composite gel

[0128] Weigh: 1350.0 g of aluminum chloride, 900.0 g of tetraethyl orthosilicate and 4500.0 mL of deionized water and add them to a hydrothermal reaction kettle. After stirring at room temperature for 12 min, continue to add 1000.0 g of aluminum triisopropoxide and 160.0 g of polyvinyl alcohol. Raise the temperature of the hydrothermal reaction kettle to 170 °C, keep warm and stir for 10 h to obtain the composite gel.

[0129] Step III, prepare porous fiber

[0130] Add the composite gel to an electrospinning machine. The temperature of electrospinning is 21 °C, the humidity is 30%, the applied voltage is 20 kV, the receiving distance is 18 cm, the perfusion speed is 5 mL / h, the sliding table moving speed is 27 cm / min, and the receiving roller rotation speed is 27 r / min. After electrospinning, obtain modified fibers. Transfer the modified fibers to a tubular furnace. After introducing nitrogen protection into the tubular furnace, the tubular furnace is heated to 650 °C at a heating rate of 5 °C / min, nitrogen is disconnected, oxygen is introduced at a flow rate of 2 L / min, after heat preservation treatment for 2 h, oxygen is disconnected, nitrogen is continuously introduced and then heated to 1300 °C at a heating rate of 6 °C / min, after heat preservation treatment for 2 h, it is naturally cooled to 135 °C, nitrogen is disconnected, and steam is introduced at a flow rate of 2 L / min, after heat preservation treatment for 2 h to obtain the porous fiber.

[0131] Step IV, prepare composite fiber precursor

[0132] The modified fibers are padded in a phosphate slurry, and through a two-padding and two-rolling process with a bath ratio of 1:21 and a padding rate of 110%, the material is then transferred to an oven at 270 °C and cured to a constant weight in a nitrogen atmosphere, and then naturally cooled to room temperature. After repeating the operation 4 times, a composite fiber precursor is obtained.

[0133] Step V. Preparation of composite fibers

[0134] Weigh: 700.0 g of the composite fiber precursor and 2700.0 mL of N,N-dimethylformamide are added to a reaction kettle and stirred. After the temperature of the reaction kettle rises to 50 °C, 240.0 g of the modified curing agent prepared in Example 3 is further added to the reaction kettle, and the pH of the reaction system is adjusted to 9 using saturated sodium hydroxide solution. After keeping the temperature and stirring for 36 min, after the reaction is completed, when the temperature of the reaction kettle drops to room temperature, the reaction solution is filtered by suction to collect the filter cake, and the filter cake is transferred to a drying oven at 70 °C and vacuum dried to a constant weight to obtain composite fibers.

[0135] Example 10

[0136] This example is used to provide a preparation method of a weather-resistant and impact-resistant material for a fiber-reinforced high-transmission-wave radome, including the following steps:

[0137] Weigh: 7000.0 g of the modified polytetrafluoroethylene prepared in Example 4, 1000.0 g of the composite fibers prepared in Example 7, 500. g of the modified curing agent prepared in Example 1, 50.0 g of benzophenone, 500.0 g of maleic anhydride, 50.0 g of tricyclohexylphosphine, 500.0 g of mica powder, and 300.0 g of triphenyl phosphate are added to a melting tank at 250 °C and stirred for 20 min. The melt is transferred to a vacuum sintering furnace. Under a nitrogen atmosphere, the temperature of the sintering furnace is increased to 350 °C at a heating rate of 8 °C / min, kept at a constant temperature for 2 h, then cooled to 120 °C at a cooling rate of 4 °C / min, and naturally cooled to room temperature to obtain the radome material.

[0138] Example 11

[0139] This example is used to provide a preparation method of a weather-resistant and impact-resistant material for a fiber-reinforced high-transmission-wave radome, including the following steps:

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

[0141] Example 12

[0142] This example is used to provide a preparation method of a weather-resistant and impact-resistant material for a fiber-reinforced high-wave-transmission radome, including the following steps:

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

[0144] Comparative Example 1

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

[0146] Comparative Example 2

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

[0148] Comparative Example 3

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

[0150] Comparative Example 4

[0151] The difference between this comparative example and Example 12 is that the use of the modified curing agent is cancelled.

[0152] Performance test:

[0153] Refer to the standard GB / T 5597-1999 "Test Method for Microwave Complex Dielectric Constant of Solid Dielectrics" to measure the wave transmission performance of the radome materials prepared in Examples 10-12 and Comparative Examples 1-3;

[0154] Refer to the standard GB / T 1843-2008 "Determination of Izod Impact Strength of Plastics" to test the impact resistance of the radome materials prepared in Examples 10-12 and Comparative Examples 1-3;

[0155] Refer to the standard GB / T 2408-2021 "Determination of Flammability of Plastics Horizontal and Vertical Methods" to test the vertical burning grade of the radome materials prepared in Examples 10-12 and Comparative Examples 1-3;

[0156] Refer to the standard GB / T 9867-2008 "Determination of Abrasion Resistance of Vulcanized Rubber or Thermoplastic Rubber (Rotary Drum Abrasion Machine Method)" to test the volume abrasion of the radome materials prepared in Examples 10-12 and Comparative Examples 1-3. The specific data is shown in Table 1;

[0157] Refer to the standard GB / T 16422.3-2022 "Plastics - Methods of Exposure to Laboratory Light Sources - Part 3: Fluorescent Ultraviolet Lamps". After the radome materials prepared in Examples 10-12 and Comparative Examples 1-3 are subjected to ultraviolet irradiation treatment, refer to the standard GB / T 5597-1999 to measure the wave transmission performance of the radome materials, refer to the standard GB / T1843-2008 to measure the Izod impact strength of the radome materials; refer to the standard GB / T 9867-2008 to measure the volume abrasion of the radome materials. The specific data is shown in Table 2.

[0158] Table 1 - Performance test data table of each specimen

[0159]

[0160]

[0161] Table 2 - Performance test data table of each specimen after ultraviolet aging

[0162]

[0163] Data analysis:

[0164] By comparing and analyzing the data in Tables 1-2, it can be found that the dielectric constant of the radome material prepared by the present invention is 2.5, the tangent value of the dielectric loss angle is 0.0002, and the Izod impact strength is 53.2 kJ·m -2, the volume wear amount is 27.1 mm 3 At the same time, the vertical burning rating is V-0, and the dielectric constant of the radome material after ultraviolet irradiation is 2.5, the dielectric loss tangent value is 0.0003, and the Izod impact strength is 52.3 kJ·m -2 , the volume wear amount is 28.1 mm 3 At the same time, the vertical burning rating is V-0;

[0165] It should be noted that in the present invention, a modified curing agent with a siloxane and double bond structure in the side chain is prepared. It modifies the modified fiber through the hydrolysis of the siloxane structure, thereby enhancing the stability of the modified fiber and its compatibility with organic materials. And the polyvinylidene fluoride chain segments after activation grafting are modified by free radical polymerization. The siloxane structure on its surface and the silica component in the modified fiber cooperate synergistically to significantly enhance the weather resistance of the material. At the same time, the two and the alumina and phosphate inside the modified fiber further enhance the flame retardant performance through the synergistic flame retardant effect. And during the high-temperature processing, the oxazine ring in the modified curing agent component undergoes ring-opening polymerization, making the modified polytetrafluoroethylene and the composite fiber closely combined, thereby significantly enhancing the impact resistance of the material;

[0166] It should be noted that in the process of preparing the modified fiber with modified polytetrafluoroethylene in the present invention, a porous fiber is first obtained through hydrolysis, electrospinning and high-temperature calcination. In addition to enhancing the wave-passing performance of the fiber through phosphate modification, the flame retardant performance of the material is enhanced through the component composite flame retardant effect. After the modified fiber is modified by the modified curing agent and coated with highly hydrophobic modified polytetrafluoroethylene, the water vapor is isolated, thereby significantly improving the stability of the phosphate structure. And the inherent low-loss characteristics of polytetrafluoroethylene form a gradient dielectric structure after filling the silica fiber structure, thereby reducing the reflection of electromagnetic waves at the interface of different media, improving the wave transmission rate, providing a low-loss phase with uniform distribution inside the material for phosphate, improving the wave transmission uniformity, and at the same time enhancing the material stability. Through the synergistic cooperation of the three, the wave transmission performance of the material is enhanced;

[0167] It should be noted that in the present invention, a modified curing agent with a long-chain structure is prepared. After its side chain structure is used to perform surface modification on the grafted polytetrafluoroethylene and the composite fiber precursor, during the process of mixing and sintering the modified polytetrafluoroethylene and the composite fiber with auxiliary materials, the oxazine ring structure in the modified curing agent component undergoes ring-opening polymerization, improving the curing efficiency of the material, thereby obtaining the radome material. The siloxane structure inside the material enhances the weather resistance of the material while cooperating synergistically with the phosphate structure. During the combustion process, the silica protection layer and the carbonization promotion effect generated cooperate synergistically to significantly enhance the flame retardant effect of the material. And the inherent low-loss characteristics of polytetrafluoroethylene and the composite fiber cooperate synergistically to significantly improve the wave transmission performance of the material.

[0168] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

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

2. The fiber-reinforced high-transmittance weather-resistant and impact-resistant material for a radome according to claim 1, characterized in that: The preparation method of the modified polytetrafluoroethylene comprises the following steps: A1. Add polytetrafluoroethylene powder into a radio frequency plasma reactor, treat it with plasma for 5-10 minutes, and then let it stand in the air for 10-15 minutes to obtain activated polytetrafluoroethylene; A2, adding allyl glycidyl ether and N,N-dimethylformamide into a reaction kettle and stirring, after the temperature of the reaction kettle is raised to 40-60°C, adding activated polytetrafluoroethylene and triethylamine into the reaction kettle, keeping warm and stirring for 30-40 minutes, and post-treating to obtain grafted polytetrafluoroethylene; A3. Add the modified curing agent and N,N-dimethylformamide into the reactor and stir. After the temperature of the reactor is raised to 60-80°C, add the grafted polytetrafluoroethylene and azobisisobutyronitrile into the reactor. After keeping warm and stirring for 1-2 hours, post-treat to obtain modified polytetrafluoroethylene.

3. The fiber-reinforced weather-resistant and impact-resistant material for a high-transmittance radome according to claim 2, characterized in that: In step A2, the usage 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 usage 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 weather-resistant and impact-resistant material for a high-transmittance radome according to claim 1, characterized in that: The preparation method of the composite fiber comprises the following steps: B1. Add aluminum chloride, tetraethyl silicate and deionized water into a hydrothermal reactor, stir at room temperature for 10-15 minutes, then continue to add triisopropoxyaluminum and polyvinyl alcohol, raise the temperature of the hydrothermal reactor to 160-180° C., keep stirring for 8-12 hours, and obtain a composite gel; B2, adding the composite gel into an electrospinning machine, obtaining modified fibers by electrospinning, and post-treating the modified fibers to obtain porous fibers; B3, the modified fiber is subjected to 3-5 times of padding modification in phosphate slurry to obtain a composite fiber precursor; B4. Add the composite fiber precursor and N,N-dimethylformamide into the reactor and stir. After the temperature of the reactor rises to 40-60°C, continue to add the modified curing agent into the reactor and use saturated sodium hydroxide solution to adjust the pH of the reaction system to 8-10. After keeping warm and stirring for 30-40 minutes, post-process to obtain the composite fiber.

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

6. The fiber-reinforced weather-resistant and impact-resistant material for a high-transmittance radome according to claim 5, characterized in that: The phosphate slurry preparation method comprises the following steps: adding phosphoric acid solution and aluminum hydroxide into a reaction kettle, raising the temperature of the reaction kettle to 60-80° C., stirring and preserving until the solution is clarified, adding chromium oxide and hydrogen peroxide into the reaction kettle, and stirring and preserving for 2-3 hours to obtain phosphate slurry.

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

8. The fiber-reinforced weather-resistant and impact-resistant material for a high-transmittance radome according to claim 1, characterized in that: The preparation method of the modified curing agent comprises the following steps: C1. Add epoxypropyltrimethoxysilane, 1,3-diamino-2-hydroxypropane, triethylamine and N,N-dimethylformamide into a reaction kettle, raise the temperature of the reaction kettle to 40-60° C., and keep the temperature for 30-40 minutes to obtain modified siloxane; C2. Add modified siloxane and tetrahydrofuran into a reflux device, introduce nitrogen protection, reduce the temperature of the reflux device to 0-3°C, continue to add formaldehyde solution to the reactor, keep warm and stir for 30-40 minutes, add 6-methyl rush diphenol solution dropwise to the reactor, after the addition is completed, the temperature of the reflux device is raised to reflux, keep warm and react for 18-20 hours, and post-treat to obtain a modified curing agent.

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

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