High-temperature-resistant fiber cloth honeycomb wave-absorbing material and preparation process thereof
By using glass fiber cloth and modified graphene oxide materials, honeycomb absorbing materials with uniform coating, good mechanical properties, good wave absorption performance and high temperature resistance were prepared, which solved the problem of insufficient material strength and high temperature resistance in the existing technology, and achieved a comprehensive improvement in performance.
Patent Information
- Application Number
- CN202510430130.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-06-13
AI Technical Summary
In the prior art, the strength and high temperature resistance of aramid paper are insufficient, and the wetting and high temperature resistance of the existing wave absorber adhesive liquid need to be improved, making it difficult to prepare a fiber cloth honeycomb absorbing material with uniform coating, good mechanical properties, good wave absorption properties and high temperature resistance.
Using glass fiber cloth as the matrix material, a wave absorber glue solution is prepared by mixing polyimide resin and modified graphene oxide and other materials. After steps such as impregnation, hot pressing, precuring and lamination pressing, a honeycomb wave absorber material with a continuous hexagonal cross-sectional shape is formed.
It significantly improves the high temperature resistance and mechanical strength of the material, and at the same time improves the wave absorption performance, and prepares honeycomb wave absorption materials with excellent performance.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of microwave absorbing materials, and discloses a high-temperature resistant fiber cloth honeycomb microwave absorbing material and a preparation process thereof. Background Art
[0002] Microwave absorbing materials can absorb and attenuate incident electromagnetic waves within a certain frequency band, and are applied in fields such as microwave absorbing equipment, anechoic chambers, and radiation protection. Materials with a honeycomb structure are commonly used matrix materials for making microwave absorbing materials. Their shape is similar to that of honeycombs in nature, which can evenly withstand external forces and have a relatively light mass, making them a current research hotspot.
[0003] In the prior art, aramid paper is commonly used as the raw material for honeycomb materials, and an absorbing agent glue solution is coated on the aramid honeycomb matrix material to achieve the effect of absorbing microwaves. However, the strength and high-temperature resistance of aramid paper need to be improved, and the wettability and high-temperature resistance of the existing absorbing agent glue solution also need to be improved. In summary, it is of great significance to study a fiber cloth honeycomb microwave absorbing material with uniform coating, good mechanical properties, good microwave absorbing properties, and high temperature resistance and its preparation process. Summary of the Invention
[0004] The purpose of the present invention is to provide a high-temperature resistant fiber cloth honeycomb microwave absorbing material and a preparation process thereof to solve the problems raised in the above background art.
[0005] To solve the above technical problems, the present invention provides the following technical solution: A preparation process of a high-temperature resistant fiber cloth honeycomb microwave absorbing material, comprising the following steps: S1: Take polyimide resin and a microwave absorbing material, mix them evenly to obtain an absorbing agent glue solution; S2: Immerse a glass fiber cloth in the absorbing agent glue solution, take it out, hot press, and pre-cure to obtain a pretreated fiber cloth; S3: Put the pretreated fiber cloth into a mold with a cross-section of a continuous hexagonal shape through a traction device. The mold and the fiber cloth are staggered and laminated layer by layer. Press (press for 1 h at 200 °C and a pressure of 5 MPa) and cure (cure for 3 h at 400 °C) through a locking device on the mold to obtain a honeycomb microwave absorbing material.
[0006] Preferably, the thickness of the glass fiber cloth is 0.2 mm, and it is purchased from Wuhan Shuangjiao Chemical Co., Ltd.
[0007] Preferably, the absorbing agent glue solution comprises the following raw materials in parts by mass: 30 - 40 parts of polyimide resin, 20 - 25 parts of a microwave absorbing material.
[0008] More optimally, the preparation of the absorbing material includes the following steps: taking graphene oxide, chloromethyltrimethoxysilane, and fluorinated polyether siloxane (hexacarbon perfluoropolyether siloxane), adding them to a 45wt% to 50wt% ethanol aqueous solution, adjusting the pH to 5 to 6, stirring at 50 to 60° C. for 4 to 6 hours, filtering, washing and drying the solid, and obtaining modified graphene oxide; Take the modified graphene oxide, add it to N,N-dimethylformamide and disperse it evenly, add 2,4-dihydroxy-2H-1,4-benzoxazine-3(4H)-one and sodium hydroxide, stir at 5-10°C for 2-4 hours to obtain an intermediate; add 1,3,5-benzenetricarboxylic acid chloride, glutaryl dichloride, 2,4-dihydroxy-2H-1,4-benzoxazine-3(4H)-one, stir at 25-30°C for 10-12 hours, filter, take the solid, wash and dry it to obtain the absorbing material.
[0009] More optimally, the modified graphene oxide comprises the following raw materials, by weight: 10-15 parts of graphene oxide, 1.5-2 parts of chloromethyltrimethoxysilane, and 0.5-0.8 parts of fluorinated polyether siloxane; The intermediate comprises the following raw materials, calculated by mass: 10-15 parts of modified graphene oxide, 100 parts of N,N-dimethylformamide, 2-3 parts of 2,4-dihydroxy-2H-1,4-benzoxazine-3(4H)-one, and 3-5 parts of sodium hydroxide; The wave absorbing material comprises the following raw materials, calculated by weight: 1-1.5 parts of 1,3,5-benzenetricarboxylic acid chloride, 2-3 parts of glutaryl dichloride, and 16-18 parts of 2,4-dihydroxy-2H-1,4-benzoxazine-3(4H)-one.
[0010] More optimally, in the honeycomb absorbing material, the side length of a single honeycomb is 5~10mm, the wall thickness is 0.1~0.5mm, and the height is 10~20mm; the volume density of the honeycomb in the honeycomb absorbing material is 30~50kg / m 3 .
[0011] More optimally, the preparation steps of the pretreated fiber cloth are: immersing the glass fiber cloth in the absorbent glue solution, taking out the glue, pressing at a pressure of 1-2 MPa for 10-20 minutes, and pre-curing at 80-100°C for 0.5-1h to obtain the pretreated fiber cloth.
[0012] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) Using fiberglass cloth as the matrix material of the honeycomb material, both the high-temperature resistance and mechanical strength are greatly improved; (2) Preparation of a wave-absorbing agent solution: The surface tension of the wave-absorbing agent solution and the dispersibility of wave-absorbing materials (such as carbon black, graphene, etc.) have a great influence on the performance of the wave-absorbing honeycomb. A lower surface tension can enable the wave-absorbing agent solution to spread rapidly and uniformly on the fiber surface, and highly dispersed wave-absorbing materials also help to improve the wave-absorbing performance; Therefore, the present invention modifies the wave-absorbing materials in the wave-absorbing agent solution: First, graphene oxide is modified with chloromethyltrimethoxysilane and perfluorohexyl polyether siloxane. The introduced fluorinated polyether siloxane can improve the stability and wettability, reduce the surface tension, and chlorine can undergo the next reaction; In the next reaction, 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one is introduced. The N element therein can enhance the wave-absorbing ability of the material, and the structure of benzoxazine can further enhance the high-temperature resistance and mechanical properties of the material; The addition amount of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one in this step needs to be controlled to ensure that the prepared intermediate still contains a large amount of hydroxyl groups that can participate in the next modification; In the next modification, 1,3,5-benzenetricarbonyl chloride and glutaroyl dichloride are introduced as cross-linking agents, and 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one is added additionally to prepare a branched structure centered on graphene oxide. The increase in the branched structure helps to reduce the surface tension and has better dispersibility. The addition amount of 1,3,5-benzenetricarbonyl chloride determines the degree of branching and needs to be controlled. Too few branched structures will not significantly improve the performance, while too many branched structures will instead lead to uneven dispersion and performance degradation; The wave-absorbing material prepared by the above steps not only helps to improve the high-temperature resistance, mechanical properties, and wettability, but also improves the dispersibility of the wave-absorbing material by increasing the molecular weight, introducing a branched structure, introducing a benzoxazine structure with good compatibility with polyimide resin, and making the ends of the branches contain active groups with good compatibility with polyimide resin, which helps to further improve the performance. Finally, a honeycomb wave-absorbing material with excellent heat resistance, strength, and wave-absorbing ability is prepared. Detailed implementation manners
[0013] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0014] It should be noted that there are no special restrictions on the purchasing manufacturers of all raw materials involved in the present invention. Exemplarily, they include: ethanol (CAS: 64-17-5); polyimide resin (KH360, Institute of Chemistry, Chinese Academy of Sciences); graphene oxide (XF002-2, Jiangsu Xianfeng Nano Materials Technology Co., Ltd.); chloromethyltrimethoxysilane (CAS: 5926-26-1); hexafluoropolyether siloxane (CAS: 1184727-90-9); N,N-dimethylformamide (CAS: 68-12-2); 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (Yuanye T55262, CAS: 17359-54-5); 1,3,5-benzenetricarbonyl chloride (CAS: 4422-95-1); glutaroyl dichloride (CAS: 2873-74-7); Unless otherwise specified, the following are all in parts by mass or mass ratio; Example 1: S1: Take 10 parts of graphene oxide, 1.5 parts of chloromethyltrimethoxysilane, and 0.6 part of hexafluoropolyether siloxane and add them to 100 parts of 50 wt% ethanol aqueous solution. Adjust the pH to 6, stir at 50 °C for 6 h, filter, wash and dry the solid to obtain modified graphene oxide; S2: Take 12 parts of modified graphene oxide, add 100 parts of N,N-dimethylformamide, disperse evenly, add 2 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one and 4 parts of sodium hydroxide, stir at 6 °C for 3 h to obtain an intermediate; add 1.2 parts of 1,3,5-benzenetricarbonyl chloride, 3 parts of glutaroyl dichloride, and 18 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, stir at 25 °C for 12 h, filter, take the solid, wash and dry it to obtain the wave-absorbing material; S3: Take 35 parts of polyimide resin and 25 parts of the wave-absorbing material, mix evenly to obtain the wave-absorbing agent glue solution: S4: Immerse the glass fiber cloth in the wave-absorbing agent glue solution, take it out, scrape the glue, extrude it at 1 MPa for 20 min, and pre-cure it at 90 °C for 0.5 h to obtain the pretreated fiber cloth; S5: Through a traction device, put the pretreated fiber cloth into a mold with a cross-section of a continuous hexagonal shape. The mold and the fiber cloth are staggered and stacked layer by layer, pressed, and cured at 400 °C for 3 h to obtain the honeycomb wave-absorbing material; in the honeycomb wave-absorbing material, the side length of a single honeycomb is 6 mm, the wall thickness is 0.2 mm, and the height is 15 mm; the bulk density of the honeycombs in the honeycomb wave-absorbing material is 40 kg / m 3 .
[0015] Example 2: S1: Take 10 parts of graphene oxide, 1.5 parts of chloromethyltrimethoxysilane, and 0.5 part of hexafluoropolyether siloxane and add them to 100 parts of 50 wt% ethanol aqueous solution. Adjust the pH to 6, stir at 50 °C for 6 h, filter, wash and dry the solid to obtain modified graphene oxide; S2: Take 10 parts of modified graphene oxide and add it to 100 parts of N,N-dimethylformamide, disperse evenly, add 2 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one and 4 parts of sodium hydroxide, stir at 6 °C for 3 h to obtain an intermediate; add 1 part of 1,3,5-benzenetricarbonyl chloride, 2 parts of glutaroyl dichloride, and 18 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, stir at 25 °C for 12 h, filter, take the solid, wash and dry it to obtain the wave-absorbing material; S3: Take 30 parts of polyimide resin and 20 parts of wave-absorbing material, mix evenly to obtain the wave-absorbing agent glue solution: S4: Immerse the glass fiber cloth in the wave-absorbing agent glue solution, take it out, scrape the glue, extrude it at 1 MPa for 20 min, and pre-cure it at 90 °C for 0.5 h to obtain the pretreated fiber cloth; S5: Through the traction device, put the pretreated fiber cloth into a mold with a continuous hexagonal cross-section. The mold and the fiber cloth are staggered and stacked layer by layer, pressed, and cured at 400 °C for 3 h to obtain the honeycomb wave-absorbing material; in the honeycomb wave-absorbing material, the side length of a single honeycomb is 6 mm, the wall thickness is 0.2 mm, and the height is 15 mm; the bulk density of the honeycombs in the honeycomb wave-absorbing material is 40 kg / m 3 。
[0016] Example 3: S1: Take 15 parts of graphene oxide, 2 parts of chloromethyltrimethoxysilane, and 0.8 part of hexafluoropolyether siloxane and add them to 100 parts of 50 wt% ethanol aqueous solution. Adjust the pH to 6, stir at 50 °C for 6 h, filter, wash and dry the solid to obtain modified graphene oxide; S2: Take 15 parts of modified graphene oxide and add it to 100 parts of N,N-dimethylformamide, disperse evenly, add 3 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one and 4 parts of sodium hydroxide, stir at 6 °C for 3 h to obtain an intermediate; add 1.5 parts of 1,3,5-benzenetricarbonyl chloride, 3 parts of glutaroyl dichloride, and 18 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, stir at 25 °C for 12 h, filter, take the solid, wash and dry it to obtain the wave-absorbing material; S3: Take 35 parts of polyimide resin and 25 parts of wave-absorbing material, mix evenly to obtain the wave-absorbing agent glue solution: S4: Immerse the glass fiber cloth in the wave-absorbing agent glue solution, take it out, scrape the glue, extrude it at 1 MPa for 20 min, and pre-cure it at 90 °C for 0.5 h to obtain the pretreated fiber cloth; S5: Through the traction device, put the pretreated fiber cloth into a mold with a cross-section of a continuous hexagonal shape. The mold and the fiber cloth are staggered, stacked layer by layer, pressed, and cured at 400 °C for 3 h to obtain a honeycomb absorbing material; in the honeycomb absorbing material, the side length of a single honeycomb is 6 mm, the wall thickness is 0.2 mm, and the height is 15 mm; the bulk density of the honeycombs in the honeycomb absorbing material is 40 kg / m 3 。
[0017] Example 4: S1: Take 15 parts of graphene oxide, 2 parts of chloromethyltrimethoxysilane, and 0.8 part of hexafluoropolyether siloxane and add them to 100 parts of a 50 wt% ethanol aqueous solution. Adjust the pH to 6, stir at 50 °C for 6 h, filter, wash and dry the solid to obtain modified graphene oxide; S2: Take 12 parts of modified graphene oxide and add it to 100 parts of N,N-dimethylformamide, disperse evenly, add 2 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one and 4 parts of sodium hydroxide, stir at 6 °C for 3 h to obtain an intermediate; add 1.2 parts of 1,3,5-benzenetricarbonyl chloride, 3 parts of glutaroyl dichloride, and 18 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, stir at 25 °C for 12 h, filter, take the solid, wash and dry it to obtain an absorbing material; S3: Take 35 parts of polyimide resin and 24 parts of the absorbing material, mix evenly to obtain an absorbing agent glue solution: S4: Immerse the glass fiber cloth in the absorbing agent glue solution, take it out, scrape off the glue, extrude it at 1 MPa for 20 min, and pre-cure it at 90 °C for 0.5 h to obtain a pretreated fiber cloth; S5: Through the traction device, put the pretreated fiber cloth into a mold with a cross-section of a continuous hexagonal shape. The mold and the fiber cloth are staggered, stacked layer by layer, pressed, and cured at 400 °C for 3 h to obtain a honeycomb absorbing material; in the honeycomb absorbing material, the side length of a single honeycomb is 6 mm, the wall thickness is 0.2 mm, and the height is 15 mm; the bulk density of the honeycombs in the honeycomb absorbing material is 40 kg / m 3 。
[0018] Comparative Example 1 (changing the addition ratio of 1,3,5-benzenetricarbonyl chloride and glutaroyl dichloride, and the other method steps are the same as those in Example 1): S1: Take 10 parts of graphene oxide, 1.5 parts of chloromethyltrimethoxysilane, and 0.6 part of hexafluoropolyether siloxane and add them to 100 parts of a 50 wt% ethanol aqueous solution. Adjust the pH to 6, stir at 50 °C for 6 h, filter, wash and dry the solid to obtain modified graphene oxide; S2: Take 12 parts of modified graphene oxide, add it to 100 parts of N,N-dimethylformamide, disperse evenly, add 2 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one and 4 parts of sodium hydroxide, stir at 6°C for 3 h to obtain an intermediate; add 3 parts of 1,3,5-benzenetricarbonyl chloride, 1.2 parts of glutaroyl dichloride, and 18 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, stir at 25°C for 12 h, filter, take the solid, wash and dry it to obtain the wave-absorbing material; S3: Take 35 parts of polyimide resin and 25 parts of the wave-absorbing material, mix evenly to obtain the wave-absorbing agent glue solution: S4: Immerse the glass fiber cloth in the wave-absorbing agent glue solution, take it out, scrape off the glue, extrude it at 1 MPa for 20 min, and pre-cure it at 90°C for 0.5 h to obtain the pretreated fiber cloth; S5: Through a traction device, put the pretreated fiber cloth into a mold with a continuous hexagonal cross-section. The mold and the fiber cloth are staggered and stacked layer by layer, pressed, and cured at 400°C for 3 h to obtain the honeycomb wave-absorbing material; in the honeycomb wave-absorbing material, the side length of a single honeycomb is 6 mm, the wall thickness is 0.2 mm, and the height is 15 mm; the bulk density of the honeycombs in the honeycomb wave-absorbing material is 40 kg / m 3 .
[0019] Comparative Example 2 (changing the addition ratio of 1,3,5-benzenetricarbonyl chloride and glutaroyl dichloride, and the other method steps are the same as those in Example 1): S1: Take 10 parts of graphene oxide, 1.5 parts of chloromethyltrimethoxysilane, and 0.6 parts of perfluorohexapolyether siloxane, add them to 100 parts of 50 wt% ethanol aqueous solution, adjust the pH to 6, stir at 50°C for 6 h, filter, wash and dry the solid to obtain modified graphene oxide; S2: Take 12 parts of modified graphene oxide, add it to 100 parts of N,N-dimethylformamide, disperse evenly, add 2 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one and 4 parts of sodium hydroxide, stir at 6°C for 3 h to obtain an intermediate; add 0.2 parts of 1,3,5-benzenetricarbonyl chloride, 4 parts of glutaroyl dichloride, and 18 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, stir at 25°C for 12 h, filter, take the solid, wash and dry it to obtain the wave-absorbing material; S3: Take 35 parts of polyimide resin and 25 parts of the wave-absorbing material, mix evenly to obtain the wave-absorbing agent glue solution: S4: Immerse the glass fiber cloth in the wave-absorbing agent glue solution, take it out, scrape off the glue, extrude it at 1 MPa for 20 min, and pre-cure it at 90°C for 0.5 h to obtain the pretreated fiber cloth; S5: Through the traction device, place the pretreated fiber cloth into a mold with a cross-section of a continuous hexagonal shape. The mold and the fiber cloth are staggered and stacked layer by layer, then pressed and cured at 400 °C for 3 h to obtain the honeycomb absorbing material. In the honeycomb absorbing material, the side length of a single honeycomb is 6 mm, the wall thickness is 0.2 mm, and the height is 15 mm. The bulk density of the honeycombs in the honeycomb absorbing material is 40 kg / m 3 .
[0020] Comparative Example 3 (changing the preparation method of the absorbing agent glue solution, and the other method steps are the same as those in Example 1): S1: Take 10 parts of graphene oxide and 0.6 part of hexafluoropolyether siloxane and add them to 100 parts of a 50 wt% ethanol aqueous solution, adjust the pH to 6, stir at 50 °C for 6 h, filter, wash and dry the solid to obtain modified graphene oxide; S2: Take 100 parts of N,N-dimethylformamide, 1.2 parts of 1,3,5-benzenetricarbonyl chloride, 3 parts of glutaroyl dichloride, 10 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, stir at 25 °C for 12 h, remove the solvent and unreacted substances, add 12 parts of modified graphene oxide and mix evenly to obtain the absorbing material; S3: Take 35 parts of polyimide resin and 25 parts of the absorbing material, mix evenly to obtain the absorbing agent glue solution: S4: Immerse the glass fiber cloth in the absorbing agent glue solution, take it out, scrape off the glue, extrude it at 1 MPa for 20 min, and pre-cure it at 90 °C for 0.5 h to obtain the pretreated fiber cloth; S5: Through the traction device, place the pretreated fiber cloth into a mold with a cross-section of a continuous hexagonal shape. The mold and the fiber cloth are staggered and stacked layer by layer, then pressed and cured at 400 °C for 3 h to obtain the honeycomb absorbing material. In the honeycomb absorbing material, the side length of a single honeycomb is 6 mm, the wall thickness is 0.2 mm, and the height is 15 mm. The bulk density of the honeycombs in the honeycomb absorbing material is 40 kg / m 3 .
[0021] Comparative Example 4 (changing the addition amount of the absorbing material, and the other method steps are the same as those in Example 1): S1: Take 10 parts of graphene oxide, 1.5 parts of chloromethyltrimethoxysilane, and 0.6 part of hexafluoropolyether siloxane and add them to 100 parts of a 50 wt% ethanol aqueous solution, adjust the pH to 6, stir at 50 °C for 6 h, filter, wash and dry the solid to obtain modified graphene oxide; S2: Take 12 parts of modified graphene oxide and add it to 100 parts of N,N-dimethylformamide. Disperse it evenly, then add 2 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one and 4 parts of sodium hydroxide. Stir at 6°C for 3 h to obtain an intermediate; add 1.2 parts of 1,3,5-benzenetricarbonyl chloride, 3 parts of glutaroyl dichloride, and 18 parts of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, and stir at 25°C for 12 h. Filter, take the solid, wash and dry it to obtain the wave-absorbing material; S3: Take 35 parts of polyimide resin and 30 parts of the wave-absorbing material, mix them evenly to obtain the wave-absorbing agent glue solution: S4: Immerse the glass fiber cloth in the wave-absorbing agent glue solution, take it out, scrape off the glue, extrude it at 1 MPa for 20 min, and pre-cure it at 90°C for 0.5 h to obtain the pretreated fiber cloth; S5: Through a traction device, put the pretreated fiber cloth into a mold with a continuous hexagonal cross-section. The mold and the fiber cloth are staggered and stacked layer by layer, then press and cure at 400°C for 3 h to obtain the honeycomb wave-absorbing material; in the honeycomb wave-absorbing material, the side length of a single honeycomb is 6 mm, the wall thickness is 0.2 mm, and the height is 15 mm; the bulk density of the honeycombs in the honeycomb wave-absorbing material is 40 kg / m 3 .
[0022] Performance test: (1) Take the wave-absorbing agent glue solutions prepared in Examples 1 to 3 and Comparative Examples 1 to 4, and test the surface tension by the hanging plate method; (2) Take the honeycomb wave-absorbing materials prepared in Examples 1 to 3 and Comparative Examples 1 to 4, and test the reflectivity (3 - 18 GHz) by the microwave anechoic chamber method; see Table 1 for details; Table 1:
[0023] Conclusion: In Comparative Example 1 and Comparative Example 2, changing the addition ratio of 1,3,5-benzenetricarbonyl chloride and glutaroyl dichloride changed the degree of branching, and the performance was inferior to that of the examples. Thus, it can be seen that the addition amount of raw materials has an important impact on the performance. In Comparative Example 3, the preparation method of the wave-absorbing agent glue solution was changed. After reacting 1,3,5-benzenetricarbonyl chloride, glutaroyl dichloride, and 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, it was directly mixed with modified graphene oxide to obtain the wave-absorbing material. Due to problems such as the reduced dispersibility of modified graphene oxide, the performance decreased; in Comparative Example 4, the addition amount of the wave-absorbing material was changed. The increase in the addition amount of the wave-absorbing material led to a decrease in its dispersibility and a resulting decrease in performance; in summary, the wave-absorbing agent glue solution prepared by the present invention has a low surface tension and is easy to spread evenly and quickly on the surface of the glass fiber cloth. The honeycomb wave-absorbing material prepared with this wave-absorbing agent glue solution has good heat resistance, strength, and wave-absorbing ability.
[0024] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A preparation process of a high temperature resistant fiber cloth honeycomb absorbing material, characterized in that: The following steps are involved: S1: Take high temperature resistant resin and absorbing material, mix them evenly, and obtain absorbing agent glue; S2: dipping the glass fiber cloth in the absorbent glue solution, scraping the glue, extruding, and pre-curing to obtain a pre-treated fiber cloth; S3: The pretreated fiber cloth is placed into a mold with a continuous hexagonal cross section by a traction device. The mold and the fiber cloth are staggered, stacked layer by layer, pressed, and cured to obtain a honeycomb absorbing material.
2. The preparation process of a high temperature resistant fiber cloth honeycomb absorbing material according to claim 1, characterized in that: The absorbent glue solution comprises the following raw materials, calculated by weight: 30-40 parts of high temperature resistant resin and 20-25 parts of absorbent material.
3. The preparation process of a high temperature resistant fiber cloth honeycomb absorbing material according to claim 1, characterized in that: The preparation of the wave absorbing material comprises the following steps: taking graphene oxide, chloromethyltrimethoxysilane and fluorinated polyether siloxane, adding them to an ethanol aqueous solution, adjusting the pH to 5-6, stirring at 50-60° C. for 4-6 hours, filtering, washing and drying the solid, and obtaining modified graphene oxide; Take the modified graphene oxide, add it to N,N-dimethylformamide and disperse it evenly, add 2,4-dihydroxy-2H-1,4-benzoxazine-3(4H)-one and sodium hydroxide, stir at 5-10°C for 2-4 hours to obtain an intermediate; add 1,3,5-benzenetricarboxylic acid chloride, glutaryl dichloride, 2,4-dihydroxy-2H-1,4-benzoxazine-3(4H)-one, stir at 25-30°C for 10-12 hours, filter, take the solid, wash and dry it to obtain the absorbing material.
4. The preparation process of a high temperature resistant fiber cloth honeycomb absorbing material according to claim 3, characterized in that: The modified graphene oxide comprises the following raw materials, calculated by weight: 10-15 parts of graphene oxide, 1.5-2 parts of chloromethyltrimethoxysilane, and 0.5-0.8 parts of fluorinated polyether siloxane; The intermediate comprises the following raw materials, calculated by mass: 10-15 parts of modified graphene oxide, 100-200 parts of N,N-dimethylformamide, 2-3 parts of 2,4-dihydroxy-2H-1,4-benzoxazine-3(4H)-one, and 3-5 parts of sodium hydroxide; The wave absorbing material comprises the following raw materials, calculated by weight: 1-1.5 parts of 1,3,5-benzenetricarboxylic acid chloride, 2-3 parts of glutaryl dichloride, and 16-18 parts of 2,4-dihydroxy-2H-1,4-benzoxazine-3(4H)-one.
5. The preparation process of a high temperature resistant fiber cloth honeycomb absorbing material according to claim 1, characterized in that: The high temperature resistant resin is polyimide resin.
6. The preparation process of a high temperature resistant fiber cloth honeycomb absorbing material according to claim 1, characterized in that: In the honeycomb absorbing material, the side length of a single honeycomb is 5~10mm, the wall thickness is 0.1~0.5mm, and the height is 10~20mm; the volume density of the honeycomb in the honeycomb absorbing material is 30~50kg / m 3 .
7. The preparation process of a high temperature resistant fiber cloth honeycomb absorbing material according to claim 1, characterized in that: The preparation steps of the pretreated fiber cloth are as follows: immersing the glass fiber cloth in the absorbent glue solution, taking out the glue, pressing at a pressure of 1-2 MPa for 10-20 minutes, and pre-curing at 80-100° C. for 0.5-1 hour to obtain the pretreated fiber cloth.
8. A honeycomb absorbing material prepared according to the preparation process of a high temperature resistant fiber cloth honeycomb absorbing material according to any one of claims 1 to 7.