A wide-spectrum stealth fabric based on exfoliated graphene and its preparation method

Abstract

The present invention belongs to the technical field of multi-layer stealth materials, and discloses a wide-spectrum stealth fabric based on exfoliated graphene and a preparation method thereof. Graphene exfoliated from cellulose nanowhiskers is used as an anti-infrared additive, and the anti-infrared additive has a layered structure. A nylon camouflage fabric is printed and dyed with acid dyes to prepare a wide-spectrum stealth fabric covering visible light, near-infrared light, and short-wave infrared light. The graphene aqueous dispersion prepared by the liquid phase exfoliation method avoids the environmental damage caused by the use of strong acids in the traditional reduction-oxidation method for preparing graphene, while ensuring the integrity of the graphene sheet structure, which can give the fabric excellent performance. The nylon camouflage fabric is printed and dyed with acid dyes and carbon nanomaterials, and the dyeing and functionalization of the fabric are simultaneously achieved, effectively shortening the finishing process and saving energy.

Description

Technical Field

[0001] The present invention belongs to the technical field of multi-layer stealth materials, and in particular relates to a wide-spectrum stealth fabric based on exfoliated graphene and a preparation method thereof. Background Art

[0002] Stealth technology is a crucial means of enhancing the survivability of weapons and equipment in warfare, evolving with the continuous advancement of detection technology. Corresponding to different detection technologies, stealth technologies can be categorized as radar stealth, visible-near-infrared stealth, infrared thermal radiation stealth, laser stealth, and acoustic stealth. Visible and infrared light are the primary operating bands for the human eye and common detection equipment. In recent years, hyperspectral imaging detection technology has been able to record information across continuous spectral bands spanning several kilometers. Combined with satellite remote sensing systems, it enables high-precision spectral detection over large areas. This requires the corresponding stealth technology to evolve from a single visible light band (wavelength 0.38-0.78μm) to a wider band encompassing near-infrared (wavelength 0.78-1.4μm) and short-wave infrared (wavelength 1.4-2.5μm).

[0003] Currently, the production of stealth textiles primarily relies on coating and finishing. Currently used near-infrared camouflage clothing uses functional camouflage coatings to reduce the clothing's near-infrared reflectivity, bringing it closer to the near-infrared reflectivity of the surrounding natural background, such as trees, green grass, withered grass, and soil. This ensures that the brightness of the target and background are similar on low-light-level night vision device screens, holographic images, and infrared photographs, thereby reducing the target's conspicuity and achieving camouflage. To evaluate the effectiveness of a target's camouflage, it's important not only to determine whether the camouflage technology matches the background color but also whether it has a roughly consistent brightness. Specifically, the wavelength and reflectivity of the reflectance spectrum in the visible light band are the primary detection parameters, while reflectivity in the near-infrared and short-wave infrared bands is the primary detection parameter.

[0004] Graphene is a two-dimensional carbon nanomaterial composed of a single layer of carbon atoms arranged in a hexagonal honeycomb lattice with sp² hybridized orbitals. It possesses high electron mobility, and its zero-gap band structure allows photons with energies greater than zero to excite electron transitions within graphene. Consequently, graphene has a very wide photon response range, encompassing electromagnetic waves from ultraviolet to infrared and even microwaves. However, graphene's light absorption rate is quite low, at only 2.3%, which limits its application in stealth.

[0005] The academic paper "High-Performance Broadband Infrared Absorbers Based on Multilayer Graphene" discloses that by regulating the number of graphene layers and the periodicity of the structure, infrared electromagnetic waves can produce significant gain and loss resonant coupling effects in the structure, with an absorptivity exceeding 80% in the 8-14μm band, which can be applied to the design of flexible infrared stealth or camouflage devices. This conclusion only focuses on thermal stealth research of mid-infrared light in the 8-14μm range, with the goal of increasing graphene's mid-infrared light absorptivity. However, it does not disclose that regulating the number of graphene layers and the periodicity of the structure can also increase the absorptivity of short-wave infrared light, that is, reduce the reflectivity and achieve infrared light stealth.

[0006] In view of this, how to design and prepare a wide-spectrum stealth fabric of visible light, near-infrared light and short-wave infrared light is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of the present invention is to address the above-mentioned deficiencies in the prior art and provide a wide-spectrum stealth fabric based on exfoliated graphene and a preparation method thereof. The invention uses an acid dye and a graphene intercalated two-dimensional material obtained by liquid-phase exfoliation of cellulose nanowhiskers to collaboratively print and dye nylon camouflage fabric, thereby reducing the reflectivity of the fabric in near-infrared light and short-wave infrared light, and achieving wide-spectrum stealth in visible light, near-infrared light, and short-wave infrared light.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The first object of the present invention is to provide a method for preparing a wide-spectrum stealth fabric based on exfoliated graphene, comprising the following specific steps:

[0010] S1. Preparation of graphene aqueous dispersion

[0011] Graphite powder and cellulose nanowhiskers are added to deionized water, stirred to dissolve and mix evenly; then, ultrasonically treated in an ice bath for a preset time, an appropriate amount of surfactant is added, and the supernatant is collected after centrifugation to obtain a graphene aqueous dispersion; the mass ratio of the graphite powder to the cellulose nanowhiskers is 1:(0.2~3), and the mass-to-volume ratio of the cellulose nanowhiskers to the deionized water is (1~20) mg:1 ml.

[0012] S2. Preparation of printing and dyeing paste

[0013] Base slurry: by weight: 5-10 parts of the first paste, 5-10 parts of ammonium sulfate, 5-10 parts of urea, 70-85 parts of water, mix well to obtain;

[0014] Color paste: Take 15-20 ml of graphene aqueous dispersion, add 0.5-2 mg of acid dye, 1.2-4 ml of binder, 0.6-2 mg of leveling agent, and 2-5 g of the second paste, stir at 400-700 rpm for 20-60 min, and mix well.

[0015] S3, sizing

[0016] Place the fabric on a glass plate, pour a line of the prepared base paste on the fabric, and apply it with a scraper. After scraping, put the fabric into an oven to dry at a temperature of 100-120°C for 10-30 minutes.

[0017] S4, Printing

[0018] Use a printing machine to squeeze the prepared color paste onto the printing screen, then place the printing screen on the sized fabric surface and print according to the camouflage pattern;

[0019] S5, steaming

[0020] Put the printed fabric into the steamer for color fixation at a temperature of 100-110°C for 1-2 hours;

[0021] S6, water washing

[0022] Add 50~60℃ warm water and wash 1~2 times, each time for 3~5 minutes, with a bath ratio of 1:30. Put the fabric into the oven to dry at a temperature of 100~120℃ for 10~30 minutes.

[0023] Furthermore, the ultrasonic power is 400W~450W, and the ultrasonic time is 1~1.5h.

[0024] Furthermore, the surfactant is one or more of stearic acid, sodium dodecylbenzenesulfonate, fatty acid glyceride, fatty acid sorbitan, and polysorbate.

[0025] Furthermore, the fabric is nylon 6, nylon 66, nylon / cotton blended, or nylon / polyester blended fabric.

[0026] Furthermore, the concentration of the graphene dispersion is 1-10 mg / ml.

[0027] Furthermore, the first paste is one or more of starch, sodium alginate, carboxymethyl cellulose, maleic anhydride, methacrylic acid, and dragon glue.

[0028] Furthermore, the second paste is one or more of starch, sodium alginate, carboxymethyl cellulose, maleic anhydride, methacrylic acid, and dragon glue.

[0029] Furthermore, the adhesive includes one or more of polyacrylate copolymer, butadiene copolymer, hydroxymethyl acrylamide, and waterborne polyurethane.

[0030] Furthermore, the leveling agent includes one or more of polyvinyl pyridine, polyvinyl pyrrolidone, and β-cyclodextrin.

[0031] The second object of the present invention is to provide a wide-spectrum stealth fabric prepared by the above-mentioned preparation method.

[0032] Furthermore, the color and brightness of the wide-spectrum stealth fabric in visible light (wavelength 0.38~0.78μm) are consistent with the standard color; the reflectivity in the near-infrared light (wavelength 0.78~1.4μm)-short-wave infrared light (wavelength 1.4~2.5μm) band is lower than that of the original fabric.

[0033] Furthermore, the wide-spectrum stealth fabric has a wide-spectrum stealth function of visible light-near infrared light-short-wave infrared light in a vegetation environment.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention provides a wide-spectrum stealth fabric based on exfoliated graphene and a preparation method thereof. A two-dimensional material intercalated with graphene exfoliated from cellulose nanowhiskers in a liquid phase is used as an anti-infrared additive, and acid dyes are used to print and dye nylon fabric to prepare a wide-spectrum stealth fabric that can withstand visible light, near-infrared light, and short-wave infrared light. The liquid-phase exfoliation method is used to prepare a graphene aqueous dispersion, which avoids the environmental damage caused by the use of strong acids in the traditional reduction-oxidation method for preparing graphene. While ensuring the integrity of the chemical structure of the graphene sheets and the controllability of the number of layers and thickness, the fabric can be endowed with excellent properties. The acid dyes and carbon nanomaterials are used to print and dye nylon fabrics, achieving both dyeing and functionalization simultaneously, effectively shortening the finishing process and saving energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Transmission electron microscopy image of graphene exfoliated from cellulose nanowhiskers;

[0037] Figure 2 Atomic force microscopy image of graphene exfoliated from cellulose nanowhiskers;

[0038] Figure 3 This is the infrared spectrum curve of graphene exfoliated from cellulose nanowhiskers;

[0039] Figure 4 conductivity of exfoliated graphene for cellulose nanowhiskers;

[0040] Figure 5 is the near infrared-short wave infrared reflectivity curve of stealth nylon camouflage fabric;

[0041] Figure 6 A photo of visible light and infrared night vision goggles made of stealth nylon camouflage fabric. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the present invention more apparent, embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0043] Unless otherwise specified, the reagents and materials used in the technical solutions provided by the present invention are all commercially available.

[0044] Example 1

[0045] This embodiment provides a method for preparing a wide-spectrum stealth fabric based on exfoliated graphene.

[0046] The specific steps are as follows:

[0047] (1) Weigh 180 mg of graphite powder and 90 mg of cellulose nanocrystals (CeNWs) and add them to 60 ml of deionized water. Stir thoroughly on a magnetic stirrer to dissolve and mix thoroughly. Then, use an ultrasonic cell disrupter at 400 W power and sonicate in an ice bath for 1 h. After sonication, add 1.8 mg of the surfactant sodium dodecylbenzenesulfonate and stir thoroughly. Place the solution in a high-speed centrifuge and centrifuge at 2000 rpm for 5 minutes. After centrifugation, collect the supernatant.

[0048] (2) Weigh 5g of maleic anhydride, 5g of ammonium sulfate, 5g of urea, and 85g of water and mix them evenly to form the base paste. Place nylon 66 fabric on a glass plate, pour a line of the prepared base paste on the fabric, and apply it with a scraper. After scraping, place the fabric in an oven to dry at 100°C for 30 minutes. Next, weigh 15ml of graphene aqueous dispersion, add 0.5mg of acid dye, 1.2ml of water-based polyurethane adhesive, 0.6mg of polyvinyl pyrrolidone leveling agent, and 2g of dragon glue, stir at 400r / min for 20 minutes, and mix evenly to obtain the color paste. Use a printing machine to squeeze the prepared color paste onto the printing screen, then place the printing screen on the sized fabric surface and print according to the camouflage pattern. Then, place the printed fabric in a steamer for color fixation at 100°C for 1 hour. Finally, add 50°C warm water and wash twice, each time for 5 minutes (bath ratio 1:30). The fabric was placed in an oven and dried at a temperature of 100°C for 30 minutes to obtain a wide-spectrum stealth fabric.

[0049] Example 2

[0050] This embodiment provides a method for preparing a wide-spectrum stealth fabric based on exfoliated graphene.

[0051] The specific steps are as follows:

[0052] (1) Weigh 180 mg of graphite powder and 180 mg of cellulose nanowhiskers (CeNW) and add them to 60 ml of deionized water. Stir thoroughly on a magnetic stirrer to dissolve and mix evenly. Then, use an ultrasonic cell disrupter at 400 W power and sonicate in an ice bath for 1 h. After sonication, add 1.8 mg of the surfactant sodium dodecylbenzenesulfonate and stir evenly. Place the solution in a high-speed centrifuge and centrifuge at 2000 r / min for 5 minutes. After centrifugation, collect the supernatant, which is the graphene aqueous dispersion.

[0053] (2) Weigh 5g of sodium alginate, 5g of ammonium sulfate, 5g of urea, and 85g of water and mix them evenly to form the base paste. Place nylon 6 fabric on a glass plate, pour a line of the prepared base paste on the fabric, and apply it with a scraper. After scraping, place the fabric in an oven to dry at 100°C for 30 minutes. Next, weigh 15ml of graphene aqueous dispersion, add 0.5mg of acid dye, 1.2ml of water-based polyurethane adhesive, 0.6mg of β-cyclodextrin leveling agent, and 2g of dragon glue, stir at 400r / min for 20 minutes, and mix evenly to obtain the color paste. Use a printing machine to squeeze the prepared color paste onto the printing screen, then place the printing screen on the sized fabric surface and print according to the camouflage pattern. Then, place the printed fabric in a steamer for color fixation at 100°C for 1 hour. Finally, add 50°C warm water and wash twice, each time for 5 minutes (bath ratio 1:30). The fabric was placed in an oven and dried at a temperature of 100°C for 30 minutes to obtain a wide-spectrum stealth fabric.

[0054] Example 3

[0055] This embodiment provides a method for preparing a wide-spectrum stealth fabric based on exfoliated graphene.

[0056] The specific steps are as follows:

[0057] (1) Weigh 180 mg of graphite powder and 360 mg of cellulose nanocrystals (CeNWs) and add them to 60 ml of deionized water. Stir thoroughly on a magnetic stirrer to dissolve and mix thoroughly. Then, use an ultrasonic cell disrupter at 400 W power and sonicate in an ice bath for 1 h. After sonication, add 1.8 mg of the surfactant sodium dodecylbenzenesulfonate and stir thoroughly. Place the solution in a high-speed centrifuge and centrifuge at 2000 rpm for 5 minutes. After centrifugation, collect the supernatant.

[0058] (2) Weigh 10g of starch, 6g of ammonium sulfate, 8g of urea, and 76g of water and mix them evenly to form the base paste. Place the nylon / cotton blended fabric on a glass plate, pour a line of the prepared base paste on the fabric, and apply it with a scraper. After scraping, place the fabric in an oven to dry at 110°C for 30 minutes. Next, weigh 20ml of graphene aqueous dispersion, add 0.6mg of acid dye, 2ml of water-based polyurethane adhesive, 0.5mg of polyvinyl pyrrolidone leveling agent, and 2g of carboxymethyl cellulose, stir at 400r / min for 20 minutes, and mix evenly to obtain the color paste. Use a printing machine to squeeze the prepared color paste onto the printing screen, then place the printing screen on the sized fabric surface and print according to the camouflage pattern. Then, place the printed fabric in a steamer for color fixation at 110°C for 1 hour. Finally, add 60°C warm water and wash twice, each time for 5 minutes (bath ratio 1:30). The fabric was placed in an oven and dried at a temperature of 100°C for 30 minutes to obtain a wide-spectrum stealth fabric.

[0059] Example 4

[0060] This embodiment provides a method for preparing a wide-spectrum stealth fabric based on exfoliated graphene.

[0061] The specific steps are as follows:

[0062] (1) Weigh 180 mg of graphite powder and 540 mg of cellulose nanocrystals (CeNWs) and add them to 60 ml of deionized water. Stir thoroughly on a magnetic stirrer to dissolve and mix thoroughly. Then, use an ultrasonic cell disrupter at 400 W power and sonicate in an ice bath for 1 h. After sonication, add 1.8 mg of the surfactant sodium dodecylbenzenesulfonate and stir thoroughly. Place the solution in a high-speed centrifuge and centrifuge at 2000 rpm for 5 minutes. After centrifugation, collect the supernatant.

[0063] (2) Weigh 5g of methacrylic acid, 5g of ammonium sulfate, 5g of urea, and 85g of water and mix them evenly to form the base paste. Place the nylon / polyester blended fabric on a glass plate, pour a line of the prepared base paste on the fabric, and apply it with a scraper. After scraping, place the fabric in an oven to dry at 100°C for 30 minutes. Next, weigh 20ml of graphene aqueous dispersion, add 0.5mg of acid dye, 1.2ml of water-based polyurethane adhesive, 0.6mg of β-cyclodextrin leveling agent, and 2g of sodium alginate, stir at 400r / min for 20 minutes, and mix evenly to obtain the color paste. Use a printing machine to squeeze the prepared color paste onto the printing screen, then place the printing screen on the sized fabric surface and print according to the camouflage pattern. Then, place the printed fabric in a steamer for color fixation at 100°C for 1 hour. Finally, add 50°C warm water and wash twice, each time for 5 minutes (bath ratio 1:30). The fabric was placed in an oven and dried at a temperature of 100°C for 30 minutes to obtain a wide-spectrum stealth fabric.

[0064] refer to Figure 1 , a transmission electron micrograph of graphene exfoliated from cellulose nanowhiskers prepared in Example 3 of this application. Graphene is distributed in sheets, and CeNWs are attached to the graphene sheets either tip-to-tip or side-by-side. The two primarily adhere to each other through π-π bonds, with the possible presence of a small amount of covalent bonds, which together increase the dispersibility of graphene in aqueous solution.

[0065] refer to Figure 2 , an atomic force microscopy image of graphene exfoliated from cellulose nanowhiskers prepared in Example 3 of the present application. The height profile curves of segments AB and CD in the image, where segment AB is the height profile curve of graphene sheets adsorbed with CeNWs, and segment CD is the height profile curve of scattered CeNWs, reveal that the graphene prepared by liquid phase exfoliation is an intercalated structure with a total thickness of approximately 26nm, while the thickness of the CeNWs is approximately 9nm.

[0066] refer to Figure 3 , is the infrared spectrum curve of the cellulose nanowhiskers exfoliated from graphene prepared in Example 3 of the present application. It can be seen that at 2903 cm -1 、1623 cm -1 , 1112 cm -1 and 1060cm -1 There is an absorption peak at 2903cm -1 The absorption peak at 1623 cm comes from CH symmetric stretching; -1 The corresponding peak is the stretching vibration absorption peak of the C=C double bond; 1112 cm -1 and 1060cm -1 This corresponds to the vibration absorption peaks of COC and CO.

[0067] refer to Figure 4 , which shows the conductivity of cellulose nanowhisker-exfoliated graphene prepared in Examples 1-4 of this application. The conductivity of the dried dispersion film gradually increases with increasing CeNW content, indicating continued improvement in dispersibility. An inflection point is observed at a graphite powder to CeNW ratio of 1:2, which serves as the optimal dispersibility ratio.

[0068] refer to Figure 5 , which shows the near-infrared-shortwave infrared reflectivity curves of the stealth nylon camouflage fabrics prepared in Examples 1-4 of this application. Compared to the original fabric, the printed fabric exhibits a significant decrease in near-infrared-shortwave infrared reflectivity. The reflectivity is lowest when the conductivity is highest, i.e., when the ratio of graphite powder to CeNWs is 1:2.

[0069] refer to Figure 6 , showing visible light and infrared night vision goggles using the stealth nylon camouflage fabric prepared in Example 3 of this application. The camouflage pattern used is jungle camouflage, primarily in green and brown, simulating a jungle environment. The printed fabric blends seamlessly with the jungle through infrared night vision goggles, achieving a superior stealth effect.

[0070] Any matters not mentioned above shall be subject to the existing technology.

[0071] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art of the present invention may make various modifications or additions to the described specific embodiments or replace them in similar ways, but they will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a wide-spectrum stealth fabric based on exfoliated graphene, characterized in that: The specific steps include: S1. Preparation of graphene aqueous dispersion Graphite powder and cellulose nanowhiskers are added to deionized water, stirred to dissolve, and mixed uniformly; then, ultrasonicated in an ice bath for a preset time, an appropriate amount of surfactant is added, and the supernatant is collected after centrifugation to obtain a graphene aqueous dispersion; the mass ratio of the graphite powder to the cellulose nanowhiskers is 1:(0.2-3), and the mass-to-volume ratio of the cellulose nanowhiskers to the deionized water is (1-20) mg:1 ml; S2. Preparation of printing and dyeing paste Base slurry: by weight: 5-10 parts of the first paste, 5-10 parts of ammonium sulfate, 5-10 parts of urea, 70-85 parts of water, mix well to obtain; Color paste: Take 15-20 ml of graphene aqueous dispersion, add 0.5-2 mg of acid dye, 1.2-4 ml of binder, 0.6-2 mg of leveling agent, and 2-5 g of the second paste, stir at 400-700 rpm for 20-60 min, and mix well. S3, sizing Place the fabric on a glass plate, pour a line of the prepared base paste on the fabric, and apply it with a scraper. After scraping, put the fabric into an oven to dry at a temperature of 100-120°C for 10-30 minutes. S4, Printing Use a printing machine to squeeze the prepared color paste onto the printing screen, then place the printing screen on the starched fabric surface and print according to the camouflage pattern; S5, steaming Put the printed fabric into the steamer for color fixation at a temperature of 100-110°C for 1-2 hours; S6, water washing Add 50-60℃ warm water and wash 1-2 times, each time for 3-5 minutes, with a bath ratio of 1:

30. Put the fabric into an oven and dry it at a temperature of 100-120℃ for 10-30 minutes to obtain a wide-spectrum stealth fabric.

2. The preparation method according to claim 1, wherein The ultrasonic power is 400-450W, and the ultrasonic time is 1-1.5h.

3. The preparation method according to claim 1, wherein The surfactant is one or more of stearic acid, sodium dodecylbenzenesulfonate, fatty acid glyceride, fatty acid sorbitan, and polysorbate.

4. The preparation method according to claim 1, wherein The fabric is nylon 6, nylon 66, nylon / cotton blended fabric, or nylon / polyester blended fabric.

5. The preparation method according to claim 1, wherein The concentration of the graphene dispersion is 4.5-10 mg / ml.

6. The preparation method according to claim 1, wherein The first paste is one or more of starch, sodium alginate, carboxymethyl cellulose, maleic anhydride, methacrylic acid, and dragon gum; the second paste is one or more of starch, sodium alginate, carboxymethyl cellulose, maleic anhydride, methacrylic acid, and dragon gum.

7. The preparation method according to claim 1, wherein The adhesive includes one or more of polyacrylate copolymer, butadiene copolymer, hydroxymethyl acrylamide, and waterborne polyurethane; the leveling agent includes one or more of polyvinyl pyridine, polyvinyl pyrrolidone, and beta-cyclodextrin.

8. A wide-spectrum stealth fabric prepared by the preparation method according to any one of claims 1 to 7.

9. The wide-spectrum stealth fabric according to claim 8, characterized in that: The wide-spectrum stealth fabric reduces reflectivity in the visible and near-infrared bands and matches the ambient color, thereby improving concealment from the naked eye and detection equipment, and has visible light-near infrared-short-wave infrared stealth functions.

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