Quartz fiber composite materials and methods for preparing thin-walled quartz antenna windows

Abstract

This invention discloses a quartz fiber composite material and a method for preparing a thin-walled quartz antenna window, belonging to the field of antenna window manufacturing technology. The quartz fiber composite material comprises the following components by weight: 18-25 parts quartz fiber yarn, 42-58 parts modified resin, 2-5 parts silane coupling agent, 1-4 parts urea, 2-6 parts nano-alumina, and 1-4 parts silicone oil. The quartz fiber composite material is prepared using the above substances, and then a thin-walled quartz antenna window is prepared using this material, giving it excellent wave transmission performance, heat resistance, and rain erosion resistance.

Description

Technical Field

[0001] This invention belongs to the field of antenna window manufacturing technology, specifically relating to quartz fiber composite materials and methods for preparing thin-walled quartz antenna windows. Background Technology

[0002] Quartz fiber composites are high-performance functional materials made of high-purity silica fiber as reinforcement and silica or other matrix materials. They possess characteristics such as high temperature resistance, low dielectric loss, excellent wave transmission, and chemical stability, occupying a key position in the aerospace field. Their long-term operating temperature can reach 1050℃, with a dielectric constant stable at around 3.0 and a dielectric loss below 0.01, meeting the requirements of high-frequency wave transmission scenarios such as airborne radomes, missile antenna radomes, and thermal protection components. With the development of precision guidance technology, antenna windows need to balance high temperature resistance, ultra-thinness, and high-frequency wave transmission performance. Traditional quartz ceramic materials, due to their low room temperature strength and high moisture absorption, have achieved breakthroughs in preparation processes represented by ceramicization treatment and three-dimensional weaving technology. By optimizing the fiber weaving structure, controlling impregnation parameters, and improving stiffness, ultra-thin antenna windows with a thickness of less than 1mm and a wave transmission rate exceeding 80% can be fabricated, providing key material support for hypersonic vehicles, missiles, and other equipment.

[0003] Patent CN110552129B discloses a high-density quartz / quartz composite material and its preparation method. The preparation method includes pretreatment of quartz fiber braids; repeated vacuum impregnation and microwave vacuum drying of the quartz fiber braids; and ceramicization treatment to finally obtain the quartz / quartz composite material. The preparation method provided by this invention has a short preparation cycle, simple and easy operation, and low cost, and is suitable for the preparation of thick fiber-reinforced silica ceramic composite materials. The composite material prepared by this method has high density, good uniformity, and excellent mechanical properties, and can be applied to radomes and other aerospace fields. Although the composite material prepared by the above method has excellent properties, it still has certain defects in terms of hydrophobicity and wave transmission performance. The insufficient hydrophobicity mainly stems from the fact that the surface of the quartz fibers and matrix materials is rich in hydrophilic groups such as hydroxyl groups, and the lack of targeted hydrophobic modification treatment during preparation, resulting in the material being prone to moisture absorption. Regarding wave transmission, although repeated vacuum impregnation improves density, it may leave tiny impurities or microstructural defects at the fiber-matrix interface. These factors can interfere with electromagnetic wave propagation and limit the performance of composite materials in high-frequency wave transmission scenarios to some extent. Summary of the Invention

[0004] The purpose of this invention is to provide a quartz fiber composite material and a method for preparing a thin-walled quartz antenna window, in order to solve the technical problems of poor wave transmission performance, hydrophobic performance and particle erosion resistance of antenna windows in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The present invention provides a quartz fiber composite material, which is composed of the following components in parts by weight: 18-25 parts quartz fiber yarn, 42-58 parts modified resin, 2-5 parts silane coupling agent, 1-4 parts urea, 2-6 parts nano alumina and 1-4 parts silicone oil.

[0007] Preferably, the method for preparing the modified resin includes the following steps:

[0008] Q1: Under nitrogen atmosphere, magnesium shavings were added to a container, followed by p-dibromobenzene, tetrahydrofuran, and iodine granules. After heating and stirring, the mixture was refluxed to obtain product 1. Under nitrogen atmosphere, chloromethyldimethylchlorosilane was added to a container containing tetrahydrofuran. After cooling, product 1 was added, and the mixture was stirred at room temperature. The mixture was then cooled, quenched, extracted, dried, and purified by vacuum distillation to obtain product 2.

[0009] Q2: Add sodium azide to the container containing product 2, stir at room temperature, pour into distilled water, extract, wash, dry, concentrate under reduced pressure to obtain product 3; add diethyl ether and lithium aluminum hydride to the container containing product 3 in sequence, stir in an ice bath, stir at room temperature, quench, filter, dry, distill under reduced pressure, purify to obtain product 4.

[0010] Q3: Under nitrogen atmosphere, product 4 was added to a container containing N-methylpyrrolidone and stirred. Then, 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride was added, the mixture was heated, cooled, ethanol was added, filtered, washed, and dried under vacuum to obtain the modified resin.

[0011] In the above process, the synthesis reaction formula of the modified resin is as follows:

[0012]

[0013] The mass spectrometry analysis results of product 1 were as follows: m / z: 283.84 (100.0%), 285.83 (66.8%), 281.84 (44.3%), 284.84 (29.9%), 282.84 (14.1%), 286.83 (13.6%), 287.83 (13.4%), 286.84 (4.5%), 285.84 (3.1%), 288.83 (2.3%), 287.84 (1.7%); the mass spectrometry analysis results of product 2 were as follows: m / z: 290.05 (100.0%), 292.05 (66.3%), 291.05 (23.4%), 294.04 (14.8%), 293.05 (9.4%). Product 3, analyzed by mass spectrometry, showed the following m / z values: 293.04 (6.8%), 292.04 (6.7%), 295.05 (2.0%), 294.05 (1.5%), 295.04 (1.3%). Product 4, analyzed by mass spectrometry, showed the following m / z values: 252.15 (100.0%), 253.15 (23.4%), 254.14 (6.8%), 254.15 (2.5%), 255.15 (1.0%).

[0014] Preferably, in Q1, the ratio of magnesium shavings, p-dibromobenzene, tetrahydrofuran, and iodine granules is (0.24-0.46) g : (1.08-1.26) g : (18-24) mL : (0.21-0.25) g. The mixture is heated to 50-60℃ and stirred for 30-45 min, then refluxed at 70-75℃ for 3-5 h. The ratio of chloromethyldimethylchlorosilane, tetrahydrofuran, and product 1 is (0.38-0.46) g : (8-11) mL : (0.46-0.52) g. The mixture is cooled to 0-1℃ and stirred at room temperature for 10-12 h. Distilled water is added for quenching, and anhydrous sodium sulfate is added for drying.

[0015] Preferably, in Q2, the ratio of sodium azide to product 2 is (0.65-0.73) g:(1.04-1.21) g, the mixture is stirred at room temperature for 5-7 h, extracted with petroleum ether, washed with saturated ammonium chloride aqueous solution, and dried with anhydrous sodium sulfate; the ratio of diethyl ether, lithium aluminum hydride, and product 3 is (0.88-0.95) g:(0.32-0.45) g:(1.02-1.24) g, the mixture is stirred in an ice bath for 10-15 min, stirred at room temperature for 4-6 h, quenched with 1 wt% ammonia water, and dried with anhydrous sodium sulfate.

[0016] Preferably, in Q3, the ratio of product 4, N-methylpyrrolidone, and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride is (2.21-2.48) g : (100-120) mL : (1.22-1.75) g. The reaction is first heated at 90-92°C for 2-4 h, and then heated at 170-180°C for 4-6 h.

[0017] Preferably, a method for preparing a thin-walled quartz antenna window using quartz fiber composite materials includes the following steps:

[0018] Step 1: Add the modified resin, silane coupling agent, nano alumina, silicone oil and urea into a container in sequence, stir and mix, and degas under vacuum to obtain resin solution;

[0019] Step 2: Pre-treat the quartz fiber yarn to obtain pre-treated quartz fiber. Then, use a braiding machine to braid the pre-treated quartz fiber into an antenna window. Then, put it into a mold, hot press, cool, vacuum, inject resin liquid, impregnate, pressurize and cure, demold, and further process to obtain the crude product.

[0020] Step 3: Clean and dry the surface of the rough product, then spray it with a composite hydrophobic coating and cure it to obtain a thin-walled quartz antenna window.

[0021] Preferably, in step one, degassing is performed at a vacuum of -0.095 MPa for 30-60 minutes; in step two, the temperature is first increased from room temperature to 400°C at a rate of 1-5°C / min and held for 60-120 minutes, then increased to 600-800°C at a rate of 1-3°C / min and held for 60-120 minutes, with an impregnation time of 60-100 minutes.

[0022] Preferably, the method for preparing the composite hydrophobic coating includes the following steps:

[0023] S1: 1H,1H,2H,2H-perfluorodecyltrimethoxysilane was added to methanol, stirred and mixed, hydrochloric acid was added dropwise, stirred at room temperature, allowed to stand, filtered, washed and dried to obtain a white solid;

[0024] S2: Add the white solid to dichloromethane, stir and mix, then add ethylene carbonate, continue stirring, filter, and obtain the composite hydrophobic coating.

[0025] In the above process, under the catalysis of hydrochloric acid, the three methoxy groups of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane are gradually replaced by hydroxyl groups, followed by a condensation reaction to obtain a white solid. Then, the white solid is physically blended with ethylene carbonate to prepare a composite hydrophobic coating.

[0026] Preferably, in S1, the ratio of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, methanol and hydrochloric acid is (28.5-30.2) g : (250-280) mL : (20-30) mL, and the mixture is stirred at room temperature for 2-4 hours.

[0027] Preferably, in step S2, the ratio of white solid, dichloromethane, and ethylene carbonate is (0.003-0.006) g: (10-15) mL: (0.11-0.15) g, and the stirring time is continued for 2-4 hours.

[0028] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0029] 1. The present invention uses the modified resin obtained as a raw material for quartz fiber composite material and uses it as a material for preparing thin-walled quartz antenna windows. In the preparation process, a composite hydrophobic coating is applied. The antenna window prepared by this method has excellent wave transmission performance, heat resistance, rain erosion resistance, particle erosion resistance and hydrophobicity.

[0030] 2. This invention uses the modified resin obtained as a raw material for quartz fiber composite materials and applies it to the preparation process of thin-walled quartz antenna windows. This effectively improves its high wave transmittance, high heat resistance, high mechanical strength, rain erosion resistance, and low moisture absorption. The fluorine atoms contained in the modified resin have low polarization characteristics, which significantly reduces the dielectric constant and loss tangent of the material, ensuring the high wave transmittance of the antenna window. The rigid aromatic heterocyclic skeleton improves the thermal stability and high-temperature oxidation resistance of the resin. At the same time, the silane structural units contained can form strong Si-O-Si chemical bonds with the surface of quartz fibers, enhancing the interfacial bonding strength between the resin and the fiber, improving its high mechanical strength and rain erosion resistance. In addition, the strong hydrophobicity of fluorine atoms and the synergistic effect of silane give the material low moisture absorption, ensuring its long-term stability of performance in harsh environments.

[0031] 3. The present invention sprays the prepared composite hydrophobic coating onto the surface of the antenna window, which can effectively improve the hydrophobicity, rain erosion resistance, particle erosion resistance, anti-icing, and wave transmission of the antenna window. The perfluoroalkyl chains contained in the composite hydrophobic coating can greatly reduce the surface energy, and combined with the micro-roughness, produce a superhydrophobic effect, making it difficult for water droplets to spread and easy to roll off, thereby achieving self-cleaning and delaying icing and reducing ice adhesion. At the same time, the dense and rigid-flexible fluorosilicone network coating can effectively buffer and disperse the impact energy of raindrops and sand particles, directly protecting the substrate from corrosion. In addition, the fluorosilicone material itself has a low dielectric constant and low loss, and it is tightly bonded to the quartz substrate, avoiding electromagnetic wave scattering and attenuation, thus maintaining excellent wave transmission performance while ensuring hydrophobic protection. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0033] Example 1: This example discloses a method for preparing the modified resin, comprising the following steps:

[0034] Q1: Under nitrogen atmosphere, 0.35g of magnesium shavings were added to a container, followed by 1.17g of p-dibromobenzene, 21mL of tetrahydrofuran, and 0.23g of iodine granules. The mixture was heated to 55℃ and stirred for 30min, then refluxed at 70℃ for 5h to obtain product 1. Under nitrogen atmosphere, 0.42g of chloromethyldimethylchlorosilane was added to a container containing 9.5mL of tetrahydrofuran. After cooling to 0℃, 0.49g of product 1 was added. The mixture was stirred at room temperature for 12h, cooled, quenched with distilled water, extracted, dried with anhydrous sodium sulfate, and purified by vacuum distillation to obtain product 2.

[0035] Q2: Add 0.68g of sodium azide to a container containing 1.12g of product 2, stir at room temperature for 6 hours, pour into distilled water, extract with petroleum ether, wash with saturated ammonium chloride aqueous solution, dry with anhydrous sodium sulfate, concentrate under reduced pressure to obtain product 3; add 0.91g of diethyl ether and 0.38g of lithium aluminum hydride to a container containing 1.13g of product 3, stir in an ice bath for 10 minutes, stir at room temperature for 6 hours, quench with 1vt% ammonia water, filter, dry with anhydrous sodium sulfate, distill under reduced pressure, purify to obtain product 4;

[0036] Q3: Under nitrogen atmosphere, 2.35g of product 4 was added to a container containing 110mL of N-methylpyrrolidone and stirred. Then, 1.48g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride was added. The mixture was first heated at 90℃ for 4h, then heated at 175℃ for 4h. After cooling, ethanol was added, the mixture was filtered, washed, and dried under vacuum to obtain the modified resin.

[0037] This embodiment discloses a quartz fiber composite material, which is composed of the following components by weight: 21 parts quartz fiber yarn, 50 parts modified resin, 3.5 parts silane coupling agent, 2.5 parts urea, 4 parts nano alumina and 2.5 parts silicone oil.

[0038] This embodiment discloses a method for preparing a composite hydrophobic coating, including the following steps:

[0039] S1: 29.5 g of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane was added to 265 mL of methanol, stirred and mixed, and then 25 mL of 1 mol / L hydrochloric acid was added dropwise. After stirring at room temperature for 4 h, the mixture was allowed to stand, filtered, washed and dried to obtain a white solid.

[0040] S2: Add 0.0045g of white solid to 12.5mL of dichloromethane, stir and mix, then add 0.13g of ethylene carbonate, continue stirring for 2 hours, filter, and obtain the composite hydrophobic coating.

[0041] This embodiment discloses a method for preparing a thin-walled quartz antenna window using quartz fiber composite materials, including the following steps:

[0042] Step 1: Add the modified resin, silane coupling agent, nano alumina, silicone oil and urea into a container in sequence, stir and mix, and degas under a vacuum of -0.095MPa for 30 minutes to obtain the resin solution.

[0043] Step 2: Pre-treat the quartz fiber yarn. First, heat the yarn from room temperature to 400℃ at a rate of 2℃ / min and hold for 120min. Then, heat the yarn to 700℃ at a rate of 2℃ / min and hold for 100min to obtain pre-treated quartz fibers. Then, use a braiding machine to braid the pre-treated quartz fibers into antenna windows. Place the windows into a mold, hot press, cool, vacuum, inject resin, impregnate for 100min, pressurize, demold, and then process to obtain the coarse product.

[0044] Step 3: Clean and dry the surface of the rough product, then spray it with a composite hydrophobic coating and cure it to obtain a thin-walled quartz antenna window.

[0045] Example 2: This example discloses a method for preparing the modified resin, comprising the following steps:

[0046] Q1: Under nitrogen atmosphere, 0.24g of magnesium shavings were added to a container, followed by 1.08g of p-dibromobenzene, 18mL of tetrahydrofuran, and 0.21g of iodine granules. The mixture was heated to 55℃ and stirred for 30min, then refluxed at 70℃ for 5h to obtain product 1. Under nitrogen atmosphere, 0.38g of chloromethyldimethylchlorosilane was added to a container containing 8mL of tetrahydrofuran. After cooling to 0℃, 0.46g of product 1 was added, and the mixture was stirred at room temperature for 12h. After cooling, the mixture was quenched with distilled water, extracted, dried with anhydrous sodium sulfate, and purified by vacuum distillation to obtain product 2.

[0047] Q2: Add 0.65g of sodium azide to a container containing 1.04g of product 2, stir at room temperature for 6 hours, pour into distilled water, extract with petroleum ether, wash with saturated ammonium chloride aqueous solution, dry with anhydrous sodium sulfate, concentrate under reduced pressure to obtain product 3; add 0.88g of diethyl ether and 0.32g of lithium aluminum hydride to a container containing 1.02g of product 3, stir in an ice bath for 10 minutes, stir at room temperature for 6 hours, quench with 1vt% ammonia water, filter, dry with anhydrous sodium sulfate, distill under reduced pressure, purify to obtain product 4;

[0048] Q3: Under nitrogen atmosphere, 2.21g of product 4 was added to a container containing 120mL of N-methylpyrrolidone and stirred. Then, 1.22g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride was added. The mixture was first heated at 90℃ for 4h, then heated at 175℃ for 4h. After cooling, ethanol was added, the mixture was filtered, washed, and dried under vacuum to obtain the modified resin.

[0049] This embodiment discloses a quartz fiber composite material, which is composed of the following components by weight: 18 parts quartz fiber yarn, 42 parts modified resin, 5 parts silane coupling agent, 4 parts urea, 6 parts nano alumina and 1 part silicone oil.

[0050] This embodiment discloses a method for preparing a composite hydrophobic coating, including the following steps:

[0051] S1: 28.5 g of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane was added to 250 mL of methanol, stirred and mixed, and then 20 mL of 1 mol / L hydrochloric acid was added dropwise. After stirring at room temperature for 4 h, the mixture was allowed to stand, filtered, washed and dried to obtain a white solid.

[0052] S2: Add 0.003g of white solid to 10mL of dichloromethane, stir and mix, then add 0.11g of ethylene carbonate, continue stirring for 2 hours, filter, and obtain the composite hydrophobic coating.

[0053] This embodiment discloses a method for preparing a thin-walled quartz antenna window using quartz fiber composite materials, including the following steps:

[0054] Step 1: Add the modified resin, silane coupling agent, nano alumina, silicone oil and urea into a container in sequence, stir and mix, and degas under a vacuum of -0.095MPa for 30 minutes to obtain the resin solution.

[0055] Step 2: Pre-treat the quartz fiber yarn. First, heat the yarn from room temperature to 400℃ at a rate of 2℃ / min and hold for 120min. Then, heat the yarn to 700℃ at a rate of 2℃ / min and hold for 100min to obtain pre-treated quartz fibers. Then, use a braiding machine to braid the pre-treated quartz fibers into antenna windows. Place the windows into a mold, hot press, cool, vacuum, inject resin, impregnate for 100min, pressurize, demold, and then process to obtain the coarse product.

[0056] Step 3: Clean and dry the surface of the rough product, then spray it with a composite hydrophobic coating and cure it to obtain a thin-walled quartz antenna window.

[0057] Example 3: This example discloses a method for preparing the modified resin, comprising the following steps:

[0058] Q1: Under nitrogen atmosphere, 0.46g of magnesium shavings were added to a container, followed by 1.26g of p-dibromobenzene, 24mL of tetrahydrofuran, and 0.25g of iodine granules. The mixture was heated to 55℃ and stirred for 30min, then refluxed at 70℃ for 5h to obtain product 1. Under nitrogen atmosphere, 0.46g of chloromethyldimethylchlorosilane was added to a container containing 11mL of tetrahydrofuran. After cooling to 0℃, 0.52g of product 1 was added, and the mixture was stirred at room temperature for 12h. After cooling, the mixture was quenched with distilled water, extracted, dried with anhydrous sodium sulfate, and purified by vacuum distillation to obtain product 2.

[0059] Q2: Add 0.73g of sodium azide to a container containing 1.21g of product 2, stir at room temperature for 6 hours, pour into distilled water, extract with petroleum ether, wash with saturated ammonium chloride aqueous solution, dry with anhydrous sodium sulfate, concentrate under reduced pressure to obtain product 3; add 0.95g of diethyl ether and 0.45g of lithium aluminum hydride to a container containing 1.24g of product 3, stir in an ice bath for 10 minutes, stir at room temperature for 6 hours, quench with 1vt% ammonia water, filter, dry with anhydrous sodium sulfate, distill under reduced pressure, purify to obtain product 4;

[0060] Q3: Under nitrogen atmosphere, 2.48 g of product 4 was added to a container containing 100 mL of N-methylpyrrolidone and stirred. Then, 1.75 g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride was added. The mixture was first heated at 90 °C for 4 h, and then heated at 175 °C for 4 h. After cooling, ethanol was added, the mixture was filtered, washed, and dried under vacuum to obtain the modified resin.

[0061] This embodiment discloses a quartz fiber composite material, which is composed of the following components by weight: 25 parts quartz fiber yarn, 58 parts modified resin, 2 parts silane coupling agent, 1 part urea, 2 parts nano alumina and 4 parts silicone oil.

[0062] This embodiment discloses a method for preparing a composite hydrophobic coating, including the following steps:

[0063] S1: 30.2 g of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane was added to 280 mL of methanol, stirred and mixed, and then 30 mL of 1 mol / L hydrochloric acid was added dropwise. After stirring at room temperature for 4 h, the mixture was allowed to stand, filtered, washed and dried to obtain a white solid.

[0064] S2: Add 0.006g of white solid to 15mL of dichloromethane, stir and mix, then add 0.15g of ethylene carbonate, continue stirring for 2 hours, filter, and obtain the composite hydrophobic coating.

[0065] This embodiment discloses a method for preparing a thin-walled quartz antenna window using quartz fiber composite materials, including the following steps:

[0066] Step 1: Add the modified resin, silane coupling agent, nano alumina, silicone oil and urea into a container in sequence, stir and mix, and degas under a vacuum of -0.095MPa for 30 minutes to obtain the resin solution.

[0067] Step 2: Pre-treat the quartz fiber yarn. First, heat the yarn from room temperature to 400℃ at a rate of 2℃ / min and hold for 120min. Then, heat the yarn to 700℃ at a rate of 2℃ / min and hold for 100min to obtain pre-treated quartz fibers. Then, use a braiding machine to braid the pre-treated quartz fibers into antenna windows. Place the windows into a mold, hot press, cool, vacuum, inject resin, impregnate for 100min, pressurize, demold, and then process to obtain the coarse product.

[0068] Step 3: Clean and dry the surface of the rough product, then spray it with a composite hydrophobic coating and cure it to obtain a thin-walled quartz antenna window.

[0069] Example 4: This example discloses a method for preparing the modified resin, comprising the following steps:

[0070] Q1: Under nitrogen atmosphere, 0.29g of magnesium shavings were added to a container, followed by 1.11g of p-dibromobenzene, 19mL of tetrahydrofuran, and 0.22g of iodine granules. The mixture was heated to 55℃ and stirred for 30min, then refluxed at 70℃ for 5h to obtain product 1. Under nitrogen atmosphere, 0.4g of chloromethyldimethylchlorosilane was added to a container containing 9mL of tetrahydrofuran. After cooling to 0℃, 0.47g of product 1 was added, and the mixture was stirred at room temperature for 12h. After cooling, the mixture was quenched with distilled water, extracted, dried with anhydrous sodium sulfate, and purified by vacuum distillation to obtain product 2.

[0071] Q2: Add 0.66g of sodium azide to a container containing 1.08g of product 2, stir at room temperature for 6 hours, pour into distilled water, extract with petroleum ether, wash with saturated ammonium chloride aqueous solution, dry with anhydrous sodium sulfate, concentrate under reduced pressure to obtain product 3; add 0.89g of diethyl ether and 0.35g of lithium aluminum hydride to a container containing 1.11g of product 3, stir in an ice bath for 10 minutes, stir at room temperature for 6 hours, quench with 1vt% ammonia water, filter, dry with anhydrous sodium sulfate, distill under reduced pressure, purify to obtain product 4;

[0072] Q3: Under nitrogen atmosphere, 2.26 g of product 4 was added to a container containing 105 mL of N-methylpyrrolidone and stirred. Then, 1.36 g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride was added. The mixture was first heated at 90 °C for 4 h, and then heated at 175 °C for 4 h. After cooling, ethanol was added, the mixture was filtered, washed, and dried under vacuum to obtain the modified resin.

[0073] This embodiment discloses a quartz fiber composite material, which is composed of the following components by weight: 19 parts quartz fiber yarn, 46 parts modified resin, 3 parts silane coupling agent, 2 parts urea, 3 parts nano alumina and 2 parts silicone oil.

[0074] This embodiment discloses a method for preparing a composite hydrophobic coating, including the following steps:

[0075] S1: 28.9 g of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane was added to 260 mL of methanol, stirred and mixed, and then 22 mL of 1 mol / L hydrochloric acid was added dropwise. After stirring at room temperature for 4 h, the mixture was allowed to stand, filtered, washed and dried to obtain a white solid.

[0076] S2: Add 0.004g of white solid to 11mL of dichloromethane, stir and mix, then add 0.14g of ethylene carbonate, continue stirring for 2 hours, filter, and obtain the composite hydrophobic coating.

[0077] This embodiment discloses a method for preparing a thin-walled quartz antenna window using quartz fiber composite materials, including the following steps:

[0078] Step 1: Add the modified resin, silane coupling agent, nano alumina, silicone oil and urea into a container in sequence, stir and mix, and degas under a vacuum of -0.095MPa for 30 minutes to obtain the resin solution.

[0079] Step 2: Pre-treat the quartz fiber yarn. First, heat the yarn from room temperature to 400℃ at a rate of 2℃ / min and hold for 120min. Then, heat the yarn to 700℃ at a rate of 2℃ / min and hold for 100min to obtain pre-treated quartz fibers. Then, use a braiding machine to braid the pre-treated quartz fibers into antenna windows. Place the windows into a mold, hot press, cool, vacuum, inject resin, impregnate for 100min, pressurize, demold, and then process to obtain the coarse product.

[0080] Step 3: Clean and dry the surface of the rough product, then spray it with a composite hydrophobic coating and cure it to obtain a thin-walled quartz antenna window.

[0081] Example 5: This example discloses a method for preparing the modified resin, comprising the following steps:

[0082] Q1: Under nitrogen atmosphere, 0.39g of magnesium shavings were added to a container, followed by 1.24g of p-dibromobenzene, 23mL of tetrahydrofuran, and 0.24g of iodine granules. The mixture was heated to 55℃ and stirred for 30min, then refluxed at 70℃ for 5h to obtain product 1. Under nitrogen atmosphere, 0.44g of chloromethyldimethylchlorosilane was added to a container containing 10mL of tetrahydrofuran. After cooling to 0℃, 0.5g of product 1 was added, and the mixture was stirred at room temperature for 12h. After cooling, the mixture was quenched with distilled water, extracted, dried with anhydrous sodium sulfate, and purified by vacuum distillation to obtain product 2.

[0083] Q2: Add 0.72g of sodium azide to a container containing 1.19g of product 2, stir at room temperature for 6 hours, pour into distilled water, extract with petroleum ether, wash with saturated ammonium chloride aqueous solution, dry with anhydrous sodium sulfate, concentrate under reduced pressure to obtain product 3; add 0.94g of diethyl ether and 0.41g of lithium aluminum hydride to a container containing 1.2g of product 3, stir in an ice bath for 10 minutes, stir at room temperature for 6 hours, quench with 1vt% ammonia water, filter, dry with anhydrous sodium sulfate, distill under reduced pressure, purify to obtain product 4;

[0084] Q3: Under nitrogen atmosphere, 2.39 g of product 4 was added to a container containing 115 mL of N-methylpyrrolidone and stirred. Then, 1.68 g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride was added. The mixture was first heated at 90 °C for 4 h, and then heated at 175 °C for 4 h. After cooling, ethanol was added, the mixture was filtered, washed, and dried under vacuum to obtain the modified resin.

[0085] This embodiment discloses a quartz fiber composite material, which is composed of the following components by weight: 24 parts quartz fiber yarn, 54 parts modified resin, 4 parts silane coupling agent, 3 parts urea, 5 parts nano alumina and 3 parts silicone oil.

[0086] This embodiment discloses a method for preparing a composite hydrophobic coating, including the following steps:

[0087] S1: 29.9 g of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane was added to 270 mL of methanol, stirred and mixed, and then 28 mL of 1 mol / L hydrochloric acid was added dropwise. After stirring at room temperature for 4 h, the mixture was allowed to stand, filtered, washed, and dried to obtain a white solid.

[0088] S2: Add 0.005g of white solid to 14mL of dichloromethane, stir and mix, then add 0.12g of ethylene carbonate, continue stirring for 2h, filter, and obtain the composite hydrophobic coating.

[0089] This embodiment discloses a method for preparing a thin-walled quartz antenna window using quartz fiber composite materials, including the following steps:

[0090] Step 1: Add the modified resin, silane coupling agent, nano alumina, silicone oil and urea into a container in sequence, stir and mix, and degas under a vacuum of -0.095MPa for 30 minutes to obtain the resin solution.

[0091] Step 2: Pre-treat the quartz fiber yarn. First, heat the yarn from room temperature to 400℃ at a rate of 2℃ / min and hold for 120min. Then, heat the yarn to 700℃ at a rate of 2℃ / min and hold for 100min to obtain pre-treated quartz fibers. Then, use a braiding machine to braid the pre-treated quartz fibers into antenna windows. Place the windows into a mold, hot press, cool, vacuum, inject resin, impregnate for 100min, pressurize, demold, and then process to obtain the coarse product.

[0092] Step 3: Clean and dry the surface of the rough product, then spray it with a composite hydrophobic coating and cure it to obtain a thin-walled quartz antenna window.

[0093] Comparative Example 1: Compared with Example 1, Comparative Example 1 used bisphenol A type epoxy resin instead of modified resin in the process of preparing thin-walled quartz antenna window, while other conditions remained unchanged.

[0094] Comparative Example 2: Compared with Example 1, Comparative Example 2 did not use a composite hydrophobic coating during the preparation of the thin-walled quartz antenna window, while all other conditions remained unchanged.

[0095] Performance testing:

[0096] The thin-walled quartz antenna windows prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests. The bending strength of the samples was tested according to GB / T 6569-2006; the tensile strength according to GB / T 1447-2005; the compressive strength according to GB / T 1448-2005; the dielectric constant and loss tangent according to GB / T 12636-1990; and the samples were tested according to GJB 150.9A-2009. Ten cycles of alternating damp heat were performed, and the moisture absorption rate was calculated. Three cycles of temperature shock tests were also conducted according to GJB 150.5A-2009. The test results are shown in Table 1.

[0097] Table 1

[0098] project Bending strength (four points) / MPa Tensile strength / MPa Compressive stress / MPa Dielectric constant (10GHz) Loss tangent (10GHz) Moisture absorption rate / % Tensile strength reduction rate / % Example 1 418.5 305.5 288.5 2.91 0.0054 0.33 2.2 Example 2 416.3 303.8 288.1 2.92 0.0056 0.36 2.4 Example 3 416.8 302.6 286.9 2.94 0.0058 0.34 2.5 Example 4 417.4 302.7 287.2 2.93 0.0057 0.35 2.3 Example 5 417.1 301.4 287.5 2.95 0.0058 0.37 2.5 Comparative Example 1 366.8 259.5 242.2 3.61 0.0183 1.16 8.6 Comparative Example 2 408.5 295.6 278.3 3.02 0.0068 1.24 4.7

[0099] As shown in Table 1, the test results indicate that thin-walled quartz antenna windows with excellent mechanical properties, wave transmission properties, hydrophobic properties, and high-temperature resistance can be prepared using the methods of Examples 1-5. A comparison between Comparative Example 1 and Examples 1-5 reveals that the use of modified resin can effectively improve the mechanical properties, wave transmission properties, hydrophobic properties, and high-temperature resistance of the thin-walled quartz antenna window. A comparison between Comparative Example 2 and Examples 1-5 shows that the use of composite hydrophobic coating can effectively improve the wave transmission properties and hydrophobic properties of the thin-walled quartz antenna window.

[0100] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0101] 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 quartz fiber composite material, characterized in that, It is composed of the following components by weight: 18-25 parts quartz fiber yarn, 42-58 parts modified resin, 2-5 parts silane coupling agent, 1-4 parts urea, 2-6 parts nano alumina and 1-4 parts silicone oil.

2. The quartz fiber composite material according to claim 1, characterized in that, The method for preparing the modified resin, Includes the following steps: Q1: Under nitrogen atmosphere, magnesium shavings were added to a container, followed by p-dibromobenzene, tetrahydrofuran, and iodine granules. After heating and stirring, the mixture was refluxed to obtain product 1. Under nitrogen atmosphere, chloromethyldimethylchlorosilane was added to a container containing tetrahydrofuran. After cooling, product 1 was added, and the mixture was stirred at room temperature. The mixture was then cooled, quenched, extracted, dried, and purified by vacuum distillation to obtain product 2. Q2: Add sodium azide to the container containing product 2, stir at room temperature, pour into distilled water, extract, wash, dry, concentrate under reduced pressure to obtain product 3; add diethyl ether and lithium aluminum hydride to the container containing product 3 in sequence, stir in an ice bath, stir at room temperature, quench, filter, dry, distill under reduced pressure, purify to obtain product 4. Q3: Under nitrogen atmosphere, product 4 was added to a container containing N-methylpyrrolidone and stirred. Then, 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride was added, the mixture was heated, cooled, ethanol was added, filtered, washed, and dried under vacuum to obtain the modified resin.

3. The quartz fiber composite material according to claim 2, characterized in that, In Q1, the ratio of magnesium shavings, p-dibromobenzene, tetrahydrofuran, and iodine granules is (0.24-0.46) g : (1.08-1.26) g : (18-24) mL : (0.21-0.25) g, and the ratio of chloromethyldimethylchlorosilane, tetrahydrofuran, and product 1 is (0.38-0.46) g : (8-11) mL : (0.46-0.52) g.

4. The quartz fiber composite material according to claim 2, characterized in that, In Q2, the ratio of sodium azide to product 2 is (0.65-0.73) g: (1.04-1.21) g; the ratio of diethyl ether, lithium aluminum hydride, to product 3 is (0.88-0.95) g: (0.32-0.45) g: (1.02-1.24) g.

5. The quartz fiber composite material according to claim 2, characterized in that, In Q3, the ratio of product 4, N-methylpyrrolidone, and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride is (2.21-2.48) g : (100-120) mL : (1.22-1.75) g.

6. A method for preparing a thin-walled quartz antenna window using the quartz fiber composite material as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Add the modified resin, silane coupling agent, nano alumina, silicone oil and urea into a container in sequence, stir and mix, and degas under vacuum to obtain the resin solution. Step 2: Pre-treat the quartz fiber yarn to obtain pre-treated quartz fiber. Then, use a braiding machine to braid the pre-treated quartz fiber into an antenna window. Then, put it into a mold, hot press, cool, vacuum, inject resin liquid, impregnate, pressurize and cure, demold, and further process to obtain the crude product. Step 3: Clean and dry the surface of the rough product, then spray it with a composite hydrophobic coating and cure it to obtain a thin-walled quartz antenna window.

7. The method for preparing a thin-walled quartz antenna window using quartz fiber composite material according to claim 6, characterized in that, In step one, degassing takes 30-60 minutes; in step two, the temperature is first increased from room temperature to 400℃ at a rate of 1-5℃ / min and held for 60-120 minutes, then increased to 600-800℃ at a rate of 1-3℃ / min and held for 60-120 minutes.

8. The method for preparing a thin-walled quartz antenna window using quartz fiber composite material according to claim 6, characterized in that, The preparation method of the composite hydrophobic coating includes the following steps: S1: 1H,1H,2H,2H-perfluorodecyltrimethoxysilane was added to methanol, stirred and mixed, hydrochloric acid was added dropwise, stirred at room temperature, allowed to stand, filtered, washed and dried to obtain a white solid; S2: Add the white solid to dichloromethane, stir and mix, then add ethylene carbonate, continue stirring, filter, and obtain the composite hydrophobic coating.

9. The method for preparing a thin-walled quartz antenna window using quartz fiber composite material according to claim 8, characterized in that, In S1, the ratio of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, methanol and hydrochloric acid is (28.5-30.2) g : (250-280) mL : (20-30) mL.

10. The method for preparing a thin-walled quartz antenna window using quartz fiber composite material according to claim 8, characterized in that, In S2, the ratio of white solid, dichloromethane, and ethylene carbonate is (0.003-0.006) g : (10-15) mL : (0.11-0.15) g.

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