A carbon-based magnetic aerogel / graphene chinlon composite fabric and a preparation method and application thereof

Abstract

The application provides a carbon-based magnetic aerogel / graphene chinlon composite fabric and a preparation method and application thereof, and belongs to the technical field of electromagnetic shielding materials. The structure of the electromagnetic shielding fabric is a three-dimensional fabric or a honeycomb structure. The three-dimensional fabric is obtained by complexly interweaving warp yarn and weft yarn with electric conductivity according to the organization structure of the warp yarn and the weft yarn, so that the fabric layers are closely arranged. In addition to the complex and diverse conductive network passage in the warp direction and the weft direction, the three-dimensional fabric forms a conductive network passage in the thickness direction. When electromagnetic waves are incident, the electromagnetic waves are absorbed and lost in the fabric. The honeycomb fabric is a "four-square cone" structure formed by the honeycomb structure. The "four-square cone" structure can make the electromagnetic waves refract multiple times in the honeycomb fabric and thus be absorbed and lost. The three-dimensional porous structure of the aerogel makes the electromagnetic waves reflect and refract multiple times in the aerogel, so that the effect of reduction is achieved. In addition, the magnetic loss mechanism provided by the magnetic material further improves the electromagnetic shielding capacity of the aerogel.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic shielding materials technology, and in particular to a carbon-based magnetic aerogel / graphene nylon composite fabric, its preparation method, and its application. Background Technology

[0002] With the increasing prevalence of highly integrated and intelligent electronic and electrical devices in fields such as communications, electrical appliances, and transportation, electromagnetic technology, while bringing great convenience to people's lives, also generates a large amount of electromagnetic radiation, leading to electromagnetic pollution. Therefore, the development of materials with electromagnetic shielding properties is imperative. Electromagnetic shielding materials can absorb, reflect, and reduce energy consumption of external and internal electromagnetic interference waves, thus providing a certain degree of interference reduction for electronic and power supply equipment. Metallic materials, as the longest-used and most widely used type of electromagnetic shielding material, possess characteristics of high stability, high mechanical strength, and excellent shielding effectiveness. However, with the continuous improvement of power supply equipment, especially switching power supplies, switching frequencies, and switching speeds, the requirements for electromagnetic shielding are becoming increasingly stringent. Ordinary electromagnetic shielding materials or shielding bodies cannot meet these increasingly stringent application demands. Simultaneously, the advent of the 5G era requires shielding materials to achieve miniaturization, thinness, wide bandwidth, and high frequency, while the high density, large mass, and narrow shielding frequency band of traditional metallic materials limit their application. Currently, the market demand for electromagnetic shielding materials is such that the electromagnetic shielding performance of traditional materials can no longer meet people's needs, which also requires the advancement of electromagnetic shielding materials towards lighter weight and higher performance.

[0003] Therefore, how to provide a lightweight electromagnetic shielding material with excellent electromagnetic interference resistance has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a carbon-based magnetic aerogel / graphene nylon composite fabric, its preparation method, and its application. The carbon-based magnetic aerogel / graphene nylon composite fabric prepared by the method provided by this invention is not only lightweight but also has excellent electromagnetic interference resistance.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing carbon-based magnetic aerogel / graphene nylon composite fabric, comprising the following steps:

[0007] (1) The electromagnetic shielding fabric, graphene dispersion, dopamine hydrochloride solution and iron oxide precursor solution are mixed and then subjected to hydrothermal reaction to obtain carbon-based magnetic hydrogel containing the fabric; the electromagnetic shielding fabric is electromagnetic shielding three-dimensional fabric or electromagnetic shielding honeycomb fabric.

[0008] (2) The carbon-based magnetic hydrogel containing fabric obtained in step (1) is freeze-dried to obtain carbon-based magnetic aerogel composite fabric.

[0009] (3) The carbon-based magnetic aerogel composite fabric obtained in step (2) is mixed with an aqueous polyurethane solution and then cured to obtain a carbon-based magnetic aerogel / graphene nylon composite fabric.

[0010] Preferably, when the electromagnetic shielding fabric in step (1) is a three-dimensional electromagnetic shielding fabric, the three-dimensional structure of the electromagnetic shielding three-dimensional fabric is through-hole orthogonal, layered orthogonal, through-hole angle interlocking or layered angle interlocking.

[0011] Preferably, in step (1), the electromagnetic shielding fabric is woven from graphene nylon filament; the specifications of the graphene nylon filament are 300D / 144F.

[0012] Preferably, in step (1), the mass ratio of graphene oxide in the graphene oxide dispersion to dopamine hydrochloride in the dopamine hydrochloride solution is 1:(0.5-2).

[0013] Preferably, in step (1), the mass ratio of graphene oxide in the graphene oxide dispersion to ferric chloride and ferrous chloride in the iron oxide precursor solution is 2:4:2.

[0014] Preferably, the hydrothermal reaction temperature in step (1) is 70-80°C and the hydrothermal reaction time is 12-20h.

[0015] Preferably, the viscosity of the aqueous polyurethane solution in step (3) is <300 mPa·S.

[0016] Preferably, the curing temperature in step (3) is 60-90°C and the curing time is 6-8 hours.

[0017] The present invention provides a carbon-based magnetic aerogel / graphene nylon composite fabric prepared by the preparation method described in the above technical solution.

[0018] This invention provides the application of the carbon-based magnetic aerogel / graphene nylon composite fabric described above in electronic devices.

[0019] This invention provides a method for preparing carbon-based magnetic aerogel / graphene nylon composite fabric, comprising the following steps: (1) mixing electromagnetic shielding fabric, graphene dispersion, dopamine hydrochloride solution and iron oxide precursor solution, and then performing a hydrothermal reaction to obtain carbon-based magnetic hydrogel containing fabric; wherein the electromagnetic shielding fabric is electromagnetic shielding three-dimensional fabric or electromagnetic shielding honeycomb fabric; (2) freeze-drying the carbon-based magnetic hydrogel containing fabric obtained in step (1) to obtain carbon-based magnetic aerogel composite fabric; (3) mixing the carbon-based magnetic aerogel composite fabric obtained in step (2) with an aqueous polyurethane solution and then curing to obtain carbon-based magnetic aerogel / graphene nylon composite fabric. The electromagnetic shielding fabric used in this invention has a three-dimensional fabric or honeycomb structure. The three-dimensional fabric involves intricately interwoven conductive warp and weft yarns according to their own structure, resulting in a tight arrangement between fabric layers. This creates a complex and diverse conductive network not only in the warp and weft directions but also in the thickness direction. When electromagnetic waves are incident, they are absorbed and lost within the fabric. The honeycomb fabric, on the other hand, utilizes a "square pyramid" structure formed by the honeycomb structure, allowing electromagnetic waves to be refracted multiple times and thus absorbed and lost. The aerogel is produced by using the reducing agent dopamine to grow Fe3O4 magnetic particles in situ within a three-dimensional graphene hydrogel, thereby… This method achieves effective hybridization of carbon materials and nano-magnetic fillers. Simultaneously, the fabric and magnetic hydrogel are freeze-dried together. The adhesion of dopamine is used to bond the electromagnetic shielding fabric and aerogel together. The aerogel is composed of graphene and magnetic materials. Due to its three-dimensional porous structure, electromagnetic waves undergo multiple reflections and refractions within the aerogel, achieving a reduction effect. Furthermore, the magnetic loss mechanism provided by the magnetic materials further enhances the electromagnetic shielding capability of the aerogel. Finally, water-based polyurethane is used for coating and reinforcement, improving the overall bonding strength of the carbon-based magnetic aerogel / graphene nylon composite fabric and ensuring its softness. The results of the examples show that the carbon-based magnetic aerogel / graphene nylon composite fabric prepared by the preparation method provided by the present invention, when tested for electromagnetic shielding effectiveness using the window method described in GJB6190-2008 "Method for Measuring the Shielding Effectiveness of Electromagnetic Shielding Materials", was found to have an electromagnetic shielding effectiveness of 36.4-48.3 dB at high frequencies, which is a certain level of electromagnetic shielding effectiveness and far exceeds the application standard of GB T26667-2011 for civilian electromagnetic shielding materials. Attached Figure Description

[0020] Figure 1 A fabrication pattern for electromagnetic shielding in three dimensions;

[0021] Figure 2 This is a diagram showing the fabric being installed on a machine for electromagnetic shielding.

[0022] Figure 3 This is a diagram of the fabric structure of a three-dimensional electromagnetic shielding structure that is orthogonally integrated.

[0023] Figure 4 This is a diagram of the fabric structure of a three-dimensional electromagnetic shielding structure with layered orthogonal layers.

[0024] Figure 5 This is a diagram of the fabric structure of a three-dimensional electromagnetic shielding structure with interlocking through-angles.

[0025] Figure 6 This is a diagram of the structure of a three-dimensional electromagnetic shielding fabric with a layered, interlocked angular structure.

[0026] Figure 7 A radial cross-sectional view of a three-dimensional electromagnetic shielding fabric with a through-hole orthogonal structure;

[0027] Figure 8 A radial cross-sectional view of a three-dimensional electromagnetic shielding fabric with a layered orthogonal structure;

[0028] Figure 9 A radial cross-sectional view of a three-dimensional electromagnetic shielding fabric with a three-dimensional structure and interlocking through-angles;

[0029] Figure 10 A radial cross-sectional view of a three-dimensional electromagnetic shielding fabric with a layered angular interlocking structure;

[0030] Figure 11 Tensile breaking strength test diagrams for four types of three-dimensional fabrics and honeycomb fabric;

[0031] Figure 12 Images of the carbon-based hydrogels obtained in Test Examples 1-6;

[0032] Figure 13 SEM image of the carbon-based aerogel prepared for test example 7;

[0033] Figure 14 SEM image of the carbon-based aerogel prepared for test example 8;

[0034] Figure 15 SEM image of the carbon-based aerogel prepared for test example 9;

[0035] Figure 16 SEM image of the carbon-based aerogel prepared in Test Example 10;

[0036] Figure 17 SEM images of the carbon-based magnetic aerogels prepared in Test Examples 11-13;

[0037] Figure 18 The image shows an electron microscope image of the carbon-based magnetic aerogel / graphene nylon composite fabric prepared in Example 1. Detailed Implementation

[0038] This invention provides a method for preparing carbon-based magnetic aerogel / graphene nylon composite fabric, comprising the following steps:

[0039] (1) The electromagnetic shielding fabric, graphene dispersion, dopamine hydrochloride solution and iron oxide precursor solution are mixed and then subjected to hydrothermal reaction to obtain carbon-based magnetic hydrogel containing the fabric; the electromagnetic shielding fabric is electromagnetic shielding three-dimensional fabric or electromagnetic shielding honeycomb fabric.

[0040] (2) The carbon-based magnetic hydrogel containing fabric obtained in step (1) is freeze-dried to obtain carbon-based magnetic aerogel composite fabric.

[0041] (3) The carbon-based magnetic aerogel composite fabric obtained in step (2) is mixed with an aqueous polyurethane solution and then cured to obtain a carbon-based magnetic aerogel / graphene nylon composite fabric.

[0042] Unless otherwise specified, all raw materials used in this invention are commercially available products well known to those skilled in the art.

[0043] This invention involves mixing electromagnetic shielding fabric, graphene dispersion, dopamine hydrochloride solution, and iron oxide precursor solution, followed by a hydrothermal reaction to obtain a carbon-based magnetic hydrogel containing the fabric; the electromagnetic shielding fabric is either a three-dimensional electromagnetic shielding fabric or an electromagnetic shielding honeycomb fabric.

[0044] In this invention, the electromagnetic shielding fabric is a three-dimensional electromagnetic shielding fabric or an electromagnetic shielding honeycomb fabric; the electromagnetic shielding fabric is preferably woven from graphene nylon filaments; the preferred specification of the graphene nylon filaments is 300D / 144F. The fabric layout of the three-dimensional electromagnetic shielding fabric in this invention is shown below. Figure 1 As shown; the installation diagram of the electromagnetic shielding honeycomb fabric is as follows. Figure 2 As shown.

[0045] In this invention, when the electromagnetic shielding fabric is a three-dimensional electromagnetic shielding fabric, the three-dimensional structure of the electromagnetic shielding three-dimensional fabric is preferably through-hole orthogonal, layered orthogonal, through-hole angular interlocking, or layered angular interlocking. In this invention, the three-dimensional structure is a through-hole orthogonal electromagnetic shielding three-dimensional fabric, as shown in the weave diagram below. Figure 3 As shown; the three-dimensional structure is a layered orthogonal electromagnetic shielding three-dimensional fabric, as illustrated in the diagram. Figure 4 As shown; the three-dimensional structure is a three-dimensional electromagnetic shielding fabric with interlocking through-angles, as illustrated in the diagram. Figure 5 As shown; the three-dimensional structure is a layered, interlocked electromagnetic shielding three-dimensional fabric, as illustrated in the diagram. Figure 6 As shown; the three-dimensional structure is a radial cross-sectional view of a through-and-orthogonal electromagnetic shielding three-dimensional fabric, as shown in the figure. Figure 7As shown; the three-dimensional structure is a radial cross-sectional view of a layered orthogonal electromagnetic shielding three-dimensional fabric, as shown in the figure. Figure 8 As shown; the radial cross-sectional view of the three-dimensional structure is a three-dimensional electromagnetic shielding fabric with through-angle interlocking, as shown in the figure. Figure 9 As shown; the radial cross-sectional view of the three-dimensional structure is a layered, interlocked electromagnetic shielding three-dimensional fabric. Figure 10 As shown.

[0046] In this invention, the preferred method for preparing the electromagnetic shielding three-dimensional fabric includes: tightly winding graphene nylon filaments of 40-60m in length onto bobbins, ensuring one graphene nylon filament is wound onto one bobbin, and then sequentially passing them through threading holes according to the bobbin sequence for heddle threading; according to the three-dimensional structure of the electromagnetic shielding three-dimensional fabric, threading and reed threading are performed, passing the graphene nylon filaments sequentially through the heddle eye according to the designed heddle threading method and through the reed eye at a ratio of 5 reeds / thread, fixing all warp yarns, and then inserting and beating the weft according to the arrangement of the warp and weft yarns to complete the weaving and obtain the electromagnetic shielding three-dimensional fabric. This invention does not have a special limitation on the number of graphene nylon filaments; it can be controlled according to the required size of the electromagnetic shielding three-dimensional fabric. As one embodiment of this invention, the length of the graphene nylon filament can be 50m; the number of graphene nylon filaments can be 100-500, or even 200-400.

[0047] In this invention, when the electromagnetic shielding fabric is an electromagnetic shielding honeycomb fabric, the preferred method for preparing the electromagnetic shielding honeycomb fabric includes: arranging graphene nylon filaments with a length of 40-60m tightly and neatly on a small-scale loom; threading heddles and reeds according to the structure of the electromagnetic shielding honeycomb fabric; passing the graphene nylon filaments sequentially through the heddle eyes according to the designed threading method and through the reed eye at a rate of 5 reeds / insertion; fixing all warp yarns; and then introducing and beating the weft according to the arrangement of the warp and weft yarns to complete the weaving process and obtain the electromagnetic shielding honeycomb fabric. This invention does not have a specific limitation on the number of graphene nylon filaments; it can be controlled according to the required size of the electromagnetic shielding honeycomb fabric. As one embodiment of this invention, the length of the graphene nylon filaments can be 50m; the number of graphene nylon filaments can be 100-500, or even 200-400.

[0048] This invention does not impose any specific limitations on the dimensions of the electromagnetic shielding fabric; it can be prepared according to the required dimensions of the carbon-based magnetic aerogel / graphene nylon composite fabric. In one embodiment of this invention, the length of the electromagnetic shielding fabric is preferably 6–12 cm, more preferably 8–10 cm; the width of the electromagnetic shielding fabric is preferably 6–12 cm, more preferably 8–10 cm.

[0049] In this invention, the concentration of the graphene oxide dispersion is preferably 1-3 mg / mL, more preferably 2 mg / mL. In this invention, the preparation method of the graphene oxide dispersion preferably includes mixing graphene oxide and water to obtain the graphene oxide dispersion. In this invention, the water is preferably distilled water. In this invention, the mixing method of the graphene oxide and water is preferably ultrasonic mixing; the ultrasonic mixing temperature is preferably 20-30°C, more preferably 25°C; the ultrasonic mixing time is preferably 0.5-2 h, more preferably 1 h; the ultrasonic mixing frequency is preferably 30-50 kHz, more preferably 40 kHz; the ultrasonic mixing is preferably performed in an ultrasonic cleaner.

[0050] In this invention, the concentration of the dopamine hydrochloride solution is preferably 1-6 mg / mL, more preferably 2-5 mg / mL, and even more preferably 3-4 mg / mL. In this invention, the preparation method of the dopamine hydrochloride solution preferably includes mixing dopamine hydrochloride and water to obtain the dopamine hydrochloride solution. In this invention, the water is preferably distilled water. In this invention, the mixing method of dopamine hydrochloride and water is preferably magnetic stirring; the temperature of the magnetic stirring is preferably 50-70°C, more preferably 60°C; the time of the magnetic stirring is preferably 1-4 hours, more preferably 2-3 hours; the speed of the magnetic stirring is preferably 700-1000 r / min, more preferably 800-900 r / min; the magnetic stirring is preferably performed on a magnetic stirrer.

[0051] In this invention, the preferred method for preparing the ferric oxide precursor solution is to mix ferric chloride solution and ferrous chloride solution, then magnetically stir and ultrasonically mix them to obtain the ferric oxide precursor solution. In this invention, the magnetic stirring temperature is preferably room temperature; the magnetic stirring time is preferably 18–24 h, more preferably 20–22 h; the magnetic stirring speed is preferably 700–800 r / min; the magnetic stirring is preferably performed on a magnetic stirrer; the ultrasonic mixing temperature is preferably 20–30 °C, more preferably 25 °C; the ultrasonic mixing time is preferably 0.5–2 h, more preferably 1–1.5 h; the ultrasonic mixing frequency is preferably 30–40 kHz, more preferably 35 kHz; and the ultrasonic mixing is preferably performed in an ultrasonic cleaner.

[0052] In this invention, the preferred method for preparing the ferric chloride solution is to mix ferric chloride and water to obtain the ferric chloride solution. In this invention, the water is preferably distilled water. In this invention, the mixing method of ferric chloride and water is preferably magnetic stirring; the temperature of the magnetic stirring is preferably 40–60°C, more preferably 50°C; the time of the magnetic stirring is preferably 10–30 min, more preferably 20 min; the speed of the magnetic stirring is preferably 400–600 r / min, more preferably 500 r / min; the magnetic stirring is preferably performed on a magnetic stirrer.

[0053] In this invention, the preferred method for preparing the ferrous chloride solution is to mix ferrous chloride and water to obtain the ferrous chloride solution. In this invention, the water is preferably distilled water. In this invention, the mixing method of ferrous chloride and water is preferably magnetic stirring; the temperature of the magnetic stirring is preferably 20–40°C, more preferably 30°C; the time of the magnetic stirring is preferably 10–30 min, more preferably 20 min; the speed of the magnetic stirring is preferably 600–1000 r / min, more preferably 800 r / min; the magnetic stirring is preferably performed on a magnetic stirrer.

[0054] In this invention, the concentration of the ferric chloride solution is preferably 2-6 mg / mL, more preferably 3-5 mg / mL, and even more preferably 4 mg / mL; the concentration of the ferrous chloride solution is preferably 1-3 mg / mL, and more preferably 2 mg / mL.

[0055] In this invention, the preferred mass ratio of graphene oxide in the graphene oxide dispersion to ferric chloride and ferrous chloride in the iron oxide precursor solution is 2:4:2. By controlling the mass ratio of graphene oxide, ferric chloride, and ferrous chloride, this invention can achieve a more uniform particle size distribution in the carbon-based magnetic aerogel.

[0056] In this invention, the preferred ratio of the mass of the electromagnetic shielding fabric, the volume of the graphene dispersion, the volume of the dopamine hydrochloride solution, and the volume of the iron oxide precursor solution is (10-20) g: (10-60) mL: (5-40) mL: (30-100) mL, more preferably (12-18) g: (15-40) mL: (10-30) mL: (35-80) mL, and even more preferably (14-16) g: (20-30) mL: (20-30) mL: (40-60) mL.

[0057] In this invention, the preferred mass ratio of graphene oxide in the graphene oxide dispersion to dopamine hydrochloride in the dopamine hydrochloride solution is 1:(0.5-2), more preferably 1:(1-1.5). By controlling the ratio of the two components, this invention facilitates the subsequent formation of a hydrogel.

[0058] In this invention, the preferred method for mixing the electromagnetic shielding fabric, graphene dispersion, dopamine hydrochloride solution, and iron oxide precursor solution is as follows: first, the electromagnetic shielding fabric is immersed in the graphene dispersion for ultrasonic mixing, and then the dopamine hydrochloride solution and iron oxide precursor solution are added. This invention does not impose specific limitations on the ultrasonic power and duration of the ultrasonic mixing; based on the technical knowledge of those skilled in the art, any method sufficient to ensure that the graphene dispersion completely and uniformly impregnates the electromagnetic shielding fabric is acceptable.

[0059] In this invention, the temperature of the hydrothermal reaction is preferably 70–80°C, more preferably 75°C; the time of the hydrothermal reaction is preferably 12–20 h, more preferably 16 h; and the hydrothermal reaction is preferably carried out in a forced-air drying oven. This invention, by controlling the temperature and time of the hydrothermal reaction, allows an aqueous solution containing electromagnetic shielding fabric and magnetic materials to polymerize under a hot-pressing environment to form a graphene hydrogel containing electromagnetic shielding fabric and magnetic particles.

[0060] After obtaining the carbon-based magnetic hydrogel containing the fabric, the present invention freeze-dries the carbon-based magnetic hydrogel containing the fabric to obtain a carbon-based magnetic aerogel composite fabric.

[0061] The present invention preferably involves first adjusting the pH value and washing the carbon-based magnetic hydrogel containing the fabric, and then freeze-drying it.

[0062] In this invention, the preferred method for adjusting the pH value is by adding ammonia. This invention does not impose specific limitations on the concentration and amount of ammonia, as long as the pH value of the carbon-based magnetic hydrogel containing the fabric meets the requirements. This invention also does not impose specific limitations on the method of adding the ammonia, which can be determined based on the technical knowledge of those skilled in the art. As one embodiment of this invention, the ammonia can be added dropwise; after adding the ammonia, the pH value of the carbon-based magnetic hydrogel containing the fabric can be 9.

[0063] In this invention, the washing is preferably performed using an ethanol solution. The ethanol solution is preferably an aqueous ethanol solution; the mass concentration of the ethanol solution is preferably 20%; and the method of removing the ethanol solution during washing is preferably extraction. This invention does not have specific limitations on the specific extraction operation, as long as it removes the ethanol solution after washing. This invention does not have specific limitations on the number of washes, until the pH value of the solution reaches 6-7. This invention removes impurities through washing.

[0064] In this invention, the freeze-drying is preferably performed by first pre-freezing at -20°C for 72 hours, and then freeze-drying at -40°C for 48 to 72 hours. By employing freeze-drying, this invention avoids affecting the structure of the product.

[0065] After obtaining the carbon-based magnetic aerogel composite fabric, the present invention mixes the carbon-based magnetic aerogel composite fabric with an aqueous polyurethane solution and then cures it to obtain a carbon-based magnetic aerogel / graphene nylon composite fabric.

[0066] In this invention, the viscosity of the aqueous polyurethane solution is preferably <300 mPa·s, more preferably 150–280 mPa·s, and even more preferably 200–250 mPa·s. In this invention, the ratio of the mass of the electromagnetic shielding fabric to the volume of the aqueous polyurethane solution is preferably (10–20) g : (15–30) mL, more preferably (12–18) g : (20–25) mL, and even more preferably (14–16) g : (20–25) mL. By controlling the amount of aqueous polyurethane solution used, this invention ensures the formation of a complete polyurethane film.

[0067] In this invention, the preferred method for mixing the reduced graphene oxide hydrogel fabric and the aqueous polyurethane solution is to spray the aqueous polyurethane solution onto the reduced graphene oxide hydrogel fabric. This invention does not impose any specific limitations on the spraying operation; any spraying method well-known to those skilled in the art can be used, provided that the aqueous polyurethane solution is sprayed evenly.

[0068] In this invention, the curing temperature is preferably 60–90°C; the curing time is preferably 6–8 hours. This invention removes the solvent from the aqueous polyurethane solution through curing, thereby forming a polyurethane film on the reduced graphene oxide hydrogel fabric. In one embodiment of this invention, the curing temperature can be 70–80°C; the curing time can be 7 hours.

[0069] The electromagnetic shielding fabric used in this invention has a three-dimensional fabric or honeycomb structure. The three-dimensional fabric involves intricately interwoven conductive warp and weft yarns according to their own structure, resulting in a tight arrangement between fabric layers. This creates a complex and diverse conductive network not only in the warp and weft directions but also in the thickness direction. When electromagnetic waves are incident, they are absorbed and lost within the fabric. The honeycomb fabric, on the other hand, utilizes a "square pyramid" structure formed by the honeycomb structure, allowing electromagnetic waves to be refracted multiple times and thus absorbed and lost. The aerogel is produced by using the reducing agent dopamine to grow Fe3O4 magnetic particles in situ within a three-dimensional graphene hydrogel, thereby… This method achieves effective hybridization of carbon materials and nano-magnetic fillers. Simultaneously, the fabric and magnetic hydrogel are freeze-dried together. The adhesion of dopamine is used to bond the electromagnetic shielding fabric and aerogel together. The aerogel is composed of graphene and magnetic materials. Due to its three-dimensional porous structure, electromagnetic waves undergo multiple reflections and refractions within the aerogel, achieving a reduction effect. Furthermore, the magnetic loss mechanism provided by the magnetic materials further enhances the electromagnetic shielding capability of the aerogel. Finally, water-based polyurethane is used for coating and reinforcement, improving the overall bonding strength of the carbon-based magnetic aerogel / graphene nylon composite fabric and ensuring its softness.

[0070] The present invention also provides a carbon-based magnetic aerogel / graphene nylon composite fabric prepared by the preparation method described above.

[0071] The present invention also provides the application of the carbon-based magnetic aerogel / graphene nylon composite fabric described in the above technical solution in electronic devices.

[0072] The present invention does not impose any special limitations on the specific operation of the application, and can be applied in a manner known to those skilled in the art.

[0073] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0074] The selection method for the electromagnetic shielding fabric in the embodiments is as follows:

[0075] ① The preparation method of the electromagnetic shielding three-dimensional fabric with a three-dimensional structure of through-through orthogonal is as follows: 200 graphene nylon filaments with a length of 50m are tightly wound onto 200 bobbins, ensuring that one graphene nylon filament is wound onto one bobbin. Then, the bobbins are passed through the threading holes in sequence for heddle threading. According to the three-dimensional structure of the electromagnetic shielding three-dimensional fabric, the heddle threading and reed threading are performed. The 200 graphene nylon filaments are passed through the heddle eye in sequence according to the designed heddle threading method and through the reed eye at a ratio of 5 reeds / insertion. All warp yarns are fixed. Then, according to the arrangement of warp and weft yarns, weft insertion and beat-up are performed to complete the weaving, resulting in a three-dimensional electromagnetic shielding three-dimensional fabric with a length of 10cm and a width of 10cm and a three-dimensional structure of through-through orthogonal.

[0076] ② The preparation method of the three-dimensional electromagnetic shielding fabric with a layered orthogonal structure is as follows: 200 graphene nylon filaments with a length of 50m are tightly wound onto 200 bobbins, ensuring that one graphene nylon filament is wound onto one bobbin. Then, the bobbins are passed through the threading holes in sequence for heddle threading. According to the three-dimensional structure of the electromagnetic shielding three-dimensional fabric, the heddle threading and reed threading are performed. The 200 graphene nylon filaments are passed through the heddle eye in sequence according to the designed heddle threading method and through the reed eye at a ratio of 5 reeds / insertion. All warp yarns are fixed. Then, according to the arrangement of the warp and weft yarns, weft insertion and beat-up are performed to complete the weaving, resulting in a three-dimensional electromagnetic shielding fabric with a layered orthogonal structure and a length of 10cm and a width of 10cm.

[0077] ③ The preparation method of the electromagnetic shielding three-dimensional fabric with a three-dimensional structure of through-angle interlocking is as follows: 200 graphene nylon filaments with a length of 50m are tightly wound on 200 bobbins, ensuring that one graphene nylon filament is wound on one bobbin. Then, the bobbins are passed through the threading holes in sequence for heddle threading. According to the three-dimensional structure of the electromagnetic shielding three-dimensional fabric, the heddle threading and reed threading are performed. The 200 graphene nylon filaments are passed through the heddle eye in sequence according to the designed heddle threading method and through the reed eye with a specification of 5 reeds / insertion. All warp yarns are fixed. Then, according to the arrangement of warp and weft yarns, weft insertion and beat-up are performed to complete the weaving and obtain an electromagnetic shielding three-dimensional fabric with a length of 10cm and a width of 10cm and a three-dimensional structure of through-angle interlocking.

[0078] ④ The preparation method of the electromagnetic shielding three-dimensional fabric with layered corner interlocking structure is as follows: 200 graphene nylon filaments with a length of 50m are tightly wound onto 200 bobbins, ensuring that one graphene nylon filament is wound onto one bobbin. Then, the bobbins are passed through the threading holes in sequence for heddle threading. According to the three-dimensional structure of the electromagnetic shielding three-dimensional fabric, the heddle threading and reed threading are performed. The 200 graphene nylon filaments are passed through the heddle eye in sequence according to the designed heddle threading method and through the reed eye with a specification of 5 reeds / insertion. All warp yarns are fixed. Then, according to the arrangement of warp and weft yarns, weft insertion and beat-up are performed to complete the weaving, and a three-dimensional electromagnetic shielding three-dimensional fabric with a length of 10cm and a width of 10cm with layered corner interlocking structure is obtained.

[0079] ⑤ When the electromagnetic shielding fabric is an electromagnetic shielding honeycomb fabric, the preparation method of the electromagnetic shielding honeycomb fabric is as follows: 200 graphene nylon filaments with a length of 50m are tightly and neatly arranged on a small sample loom; according to the structure of the electromagnetic shielding honeycomb fabric, the heddles and reeds are threaded, and the 200 graphene nylon filaments are passed through the heddle eye in sequence according to the designed heddle threading method and through the reed eye with a specification of 5 reeds / insertion, and all the warp yarns are fixed. Then, according to the arrangement of the warp and weft yarns, the weft is introduced and beaten up to complete the weaving and obtain an electromagnetic shielding honeycomb fabric with a length of 10cm and a width of 10cm.

[0080] The graphene nylon filament used in the above preparation has a specification of 300D / 144F.

[0081] The basic characterization of the above four types of three-dimensional fabrics and honeycomb fabrics was measured, including warp density, weft density, and dimensions. The basic information of the electromagnetic shielding fabrics obtained is shown in Table 1:

[0082] Table 1 Basic Information on Electromagnetic Shielding Fabrics

[0083] Sample Dimensions (cm) Dense root density (roots / 10cm) Weft density (roots / 10cm) Penetrating orthogonal 10×10 200 190 Hierarchical orthogonal 10×10 200 195 Through-angle interlocking 10×10 200 192 Layered corner interlocking 10×10 200 189 honeycomb 10×10 200 192

[0084] According to the methods described in GB / T 3923.1-2013 "Textiles - Tensile Properties of Fabrics", tensile breaking strength tests were conducted on four types of three-dimensional fabrics and honeycomb fabrics. The results are as follows: Figure 11 As shown. By Figure 11 It can be seen that the fracture strength of the layered corner interlocking is greater than 250N, and its mechanical properties are the best.

[0085] The shielding effectiveness of four types of three-dimensional fabrics and honeycomb fabrics against electromagnetic waves at six frequency points (30MHz, 450MHz, 1GHz, 5GHz, 10GHz, and 188GHz) was tested using the shielded room window method. The test results are shown in Table 2.

[0086] Table 2 Shielding effectiveness of electromagnetic shielding fabrics

[0087] Sample Hierarchical orthogonal Penetrating orthogonal Layered corner interlocking Through-angle interlocking plain weave 30MHz 8 6 9 6 2 450MHz 10 10 15 8 4 1GHz 14 10 14 7 3 5GHz 7 5 8 9 6 10GHz 7 6 9 7 5 18GHz 8 7 21 5 6

[0088] As shown in Table 2, the layered angle interlocking method exhibits the best shielding effectiveness at both high and low frequencies, especially at 18 GHz, exceeding the 20 dB application standard of GBT26667-2011 for civilian electromagnetic shielding materials. To unify variables, the warp and weft densities of the five fabrics were standardized. The difference in electromagnetic shielding effectiveness is due to the different fabric structures. From the radial cross-section of the fabrics, the weft and warp yarns of the layered angle interlocking method interweave at a 45° angle. When electromagnetic waves pass through the fabric perpendicularly at 90°, more energy is blocked on the fabric surface, thus achieving electromagnetic shielding. Furthermore, compared to other fabrics, the layered angle interlocking method has more interlacing points, forming a complex and interwoven conductive path, resulting in better electromagnetic shielding. Therefore, the electromagnetic shielding effect is best when the three-dimensional structure of the electromagnetic shielding fabric is layered angle interlocking.

[0089] In summary, a three-dimensional electromagnetic shielding fabric with layered corner interlocking structure was selected for the preparation of carbon-based magnetic aerogel / graphene nylon composite fabric.

[0090] Example 1

[0091] A method for preparing a carbon-based magnetic aerogel / graphene nylon composite fabric is as follows:

[0092] (1) Add graphene oxide to distilled water and then perform ultrasonic mixing in an ultrasonic cleaner to obtain a graphene oxide dispersion; the ultrasonic mixing temperature is 25℃, the ultrasonic mixing time is 1h, and the ultrasonic mixing frequency is 40kHz.

[0093] (2) Add dopamine hydrochloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a dopamine hydrochloride solution; the temperature of the magnetic stirring is 60℃, the stirring time is 2h, and the stirring speed is 800r / min.

[0094] (3) Add ferric chloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a ferric chloride solution; the temperature of the magnetic stirring is 50℃, the stirring time is 20min, and the stirring speed is 500r / min; the concentration of the ferric chloride solution is 4mg / mL.

[0095] (4) Add ferrous chloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a ferrous chloride solution; the temperature of the magnetic stirring is 30℃, the stirring time is 20min, and the stirring speed is 800r / min; the concentration of the ferrous chloride solution is 2mg / mL.

[0096] (5) The ferric chloride solution obtained in step (3) and the ferrous chloride solution obtained in step (4) are mixed and first magnetically stirred on a magnetic stirrer, and then ultrasonically mixed in an ultrasonic cleaner to obtain a ferric oxide precursor solution; the magnetic stirring temperature is room temperature, the magnetic stirring time is 20h, and the magnetic stirring speed is 800r / min; the ultrasonic mixing temperature is 25℃, the ultrasonic mixing time is 1h, and the ultrasonic mixing frequency is 35kHz; the mass ratio of ferric chloride to ferrous chloride in the ferric oxide precursor solution is 2:1;

[0097] (6) First, the electromagnetic shielding fabric is placed in the graphene dispersion for ultrasonic mixing, then dopamine hydrochloride solution and iron oxide precursor solution are added, and then placed in a forced-air drying oven for hydrothermal reaction at 75°C for 16 hours to obtain a carbon-based magnetic hydrogel containing the fabric; the electromagnetic shielding fabric is the three-dimensional electromagnetic shielding fabric with layered corner interlocking structure prepared above; the length of the electromagnetic shielding fabric is 10cm, the width is 10cm, and the mass of the electromagnetic shielding fabric is 15.8g; the amount of the graphene dispersion is 20mL, and the concentration of the graphene oxide dispersion is 2mg / mL; the amount of the dopamine hydrochloride solution is 20mL, and the concentration of the dopamine hydrochloride solution is 2mg / mL; the mass ratio of graphene oxide in the graphene oxide dispersion to the mass ratio of dopamine hydrochloride in the dopamine hydrochloride solution is 1:1; the amount of the iron oxide precursor solution is 40mL, and the mass ratio of ferric chloride to ferrous chloride in the iron oxide precursor solution is 2:1;

[0098] (7) Add ammonia to the carbon-based magnetic hydrogel containing the fabric obtained in step (6) until the pH value is 9, then wash with an ethanol aqueous solution with a mass concentration of 20% until the pH value is 7, extract the ethanol aqueous solution, and finally pre-freeze at -20℃ for 72h and freeze-dry at -40℃ for 72h to obtain carbon-based magnetic aerogel composite fabric.

[0099] (8) Spray 20 mL of aqueous polyurethane solution onto the reduced graphene oxide hydrogel fabric obtained in step (7), and then cure it at 80°C for 8 hours to obtain carbon-based magnetic aerogel / graphene nylon composite fabric.

[0100] Test Example 1

[0101] 1) Add graphene oxide to distilled water and then perform ultrasonic mixing in an ultrasonic cleaner to obtain a graphene oxide dispersion; the ultrasonic mixing temperature is 25℃, the ultrasonic mixing time is 1h, and the ultrasonic mixing frequency is 40kHz.

[0102] 2) Add dopamine hydrochloride to distilled water, and then stir magnetically on a magnetic stirrer to obtain a dopamine hydrochloride solution; the temperature of the magnetic stirring is 60℃, the stirring time is 2h, and the stirring speed is 800r / min.

[0103] 3) The graphene dispersion and the dopamine hydrochloride solution were mixed and then placed in a forced-air drying oven for hydrothermal reaction at 75°C for 16 hours to obtain a carbon-based hydrogel; the amount of the graphene dispersion was 20 mL, and the concentration of the graphene oxide dispersion was 2 mg / mL; the amount of the dopamine hydrochloride solution was 20 mL, and the concentration of the dopamine hydrochloride solution was 1 mg / mL; the mass ratio of graphene oxide in the graphene oxide dispersion to dopamine hydrochloride in the dopamine hydrochloride solution was 1:0.5.

[0104] Test Example 2

[0105] In step 3), the amount of graphene dispersion used is 20 mL, and the concentration of graphene oxide dispersion is 2 mg / mL; the amount of dopamine hydrochloride solution used is 20 mL, and the concentration of dopamine hydrochloride solution is 2 mg / mL; the mass ratio of graphene oxide in the graphene oxide dispersion to dopamine hydrochloride in the dopamine hydrochloride solution is 1:1.

[0106] Other conditions are the same as in Test Case 1.

[0107] Test Example 3

[0108] In step 3), the amount of graphene dispersion used is 20 mL, and the concentration of graphene oxide dispersion is 2 mg / mL; the amount of dopamine hydrochloride solution used is 20 mL, and the concentration of dopamine hydrochloride solution is 3 mg / mL; the mass ratio of graphene oxide in the graphene oxide dispersion to dopamine hydrochloride in the dopamine hydrochloride solution is 1:1.5.

[0109] Other conditions are the same as in Test Case 1.

[0110] Test Example 4

[0111] In step 3), the amount of graphene dispersion used is 20 mL, and the concentration of graphene oxide dispersion is 2 mg / mL; the amount of dopamine hydrochloride solution used is 20 mL, and the concentration of dopamine hydrochloride solution is 4 mg / mL; the mass ratio of graphene oxide in the graphene oxide dispersion to dopamine hydrochloride in the dopamine hydrochloride solution is 1:2.

[0112] Other conditions are the same as in Test Case 1.

[0113] Test Example 5

[0114] In step 3), the amount of graphene dispersion used is 20 mL, and the concentration of graphene oxide dispersion is 2 mg / mL; the amount of dopamine hydrochloride solution used is 20 mL, and the concentration of dopamine hydrochloride solution is 5 mg / mL; the mass ratio of graphene oxide in the graphene oxide dispersion to dopamine hydrochloride in the dopamine hydrochloride solution is 1:2.5.

[0115] Other conditions are the same as in Test Case 1.

[0116] Test Example 6

[0117] In step 3), the amount of graphene dispersion used is 20 mL, and the concentration of graphene oxide dispersion is 2 mg / mL; the amount of dopamine hydrochloride solution used is 20 mL, and the concentration of dopamine hydrochloride solution is 6 mg / mL; the mass ratio of graphene oxide in graphene oxide dispersion to dopamine hydrochloride in dopamine hydrochloride solution is 1:3.

[0118] Other conditions are the same as in Test Case 1.

[0119] To investigate the effect of the ratio of graphene oxide to dopamine hydrochloride on the structure of carbon-based hydrogels, tests were conducted, namely Test Examples 1–6. Images of the carbon-based hydrogels obtained in Test Examples 1–6 are shown below. Figure 12 As shown. Figure 12 In the images, #1 to #6 are, respectively, photographs of the carbon-based hydrogels prepared in Test Examples 1 to 6. Figure 12 It can be seen that as the content of dopamine hydrochloride in carbon-based hydrogels increases, the appearance of carbon-based hydrogels changes. When the mass ratio of graphene oxide to dopamine hydrochloride is less than 1:1, the appearance of carbon-based hydrogels is irregular. When the mass ratio of graphene oxide to dopamine hydrochloride is greater than 1:2, the structure of carbon-based hydrogels begins to collapse. When the ratio reaches 1:3, hydrogels cannot be formed.

[0120] Test Examples 7-10

[0121] Ammonia was added dropwise to the carbon-based hydrogels obtained in Test Examples 1 to 4 until the pH value was 9. Then, the hydrogels were washed with a 20% ethanol aqueous solution until the pH value was 7. The ethanol aqueous solution was then extracted. Finally, the hydrogels were pre-frozen at -20°C for 72 hours and freeze-dried at -40°C for 72 hours to obtain carbon-based aerogels, as shown in Test Examples 7 to 10.

[0122] The carbon-based aerogels prepared in Test Examples 7–10 were observed by scanning electron microscopy, and the obtained SEM images are shown in the following figures. Figures 13-16 As shown. By Figures 13-16It can be seen that in the carbon-based aerogel prepared in Test Example 1, the aerogel has excessively large sheets and insufficient pore size; in the carbon-based aerogel prepared in Test Example 3, the aerogel exhibits agglomeration and accumulation; and in the carbon-based aerogel prepared in Test Example 4, the aerogel exhibits spherical encapsulation. Therefore, a mass ratio of 1:1 for graphene oxide and dopamine hydrochloride is selected as the optimal value for the basic aerogel loaded with Fe3O4 particles.

[0123] Test Example 11

[0124] (1) Add graphene oxide to distilled water and then perform ultrasonic mixing in an ultrasonic cleaner to obtain a graphene oxide dispersion; the ultrasonic mixing temperature is 25℃, the ultrasonic mixing time is 1h, and the ultrasonic mixing frequency is 40kHz.

[0125] (2) Add dopamine hydrochloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a dopamine hydrochloride solution; the temperature of the magnetic stirring is 60℃, the stirring time is 2h, and the stirring speed is 800r / min.

[0126] (3) Add ferric chloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a ferric chloride solution; the temperature of the magnetic stirring is 50℃, the stirring time is 20min, and the stirring speed is 500r / min; the concentration of the ferric chloride solution is 2mg / mL.

[0127] (4) Add ferrous chloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a ferrous chloride solution; the temperature of the magnetic stirring is 30℃, the stirring time is 20min, and the stirring speed is 800r / min; the concentration of the ferrous chloride solution is 1mg / mL.

[0128] (5) The ferric chloride solution obtained in step (3) and the ferrous chloride solution obtained in step (4) are mixed and first magnetically stirred on a magnetic stirrer, and then ultrasonically mixed in an ultrasonic cleaner to obtain a ferric oxide precursor solution; the magnetic stirring temperature is room temperature, the magnetic stirring time is 20h, and the magnetic stirring speed is 800r / min; the ultrasonic mixing temperature is 25℃, the ultrasonic mixing time is 1h, and the ultrasonic mixing frequency is 35kHz; the mass ratio of ferric chloride to ferrous chloride in the ferric oxide precursor solution is 2:1;

[0129] (6) Add the dopamine hydrochloride solution obtained in step (2) and the iron oxide precursor solution obtained in step (5) to the graphene dispersion obtained in step (1), and then place it in a drying oven for hydrothermal reaction at 75°C for 16 hours to obtain carbon-based magnetic hydrogel; the amount of graphene dispersion is 20 mL, and the concentration of graphene oxide dispersion is 2 mg / mL; the amount of dopamine hydrochloride solution is 20 mL, and the concentration of dopamine hydrochloride solution is 2 mg / mL; the amount of iron oxide precursor solution is 40 mL, and the mass ratio of ferric chloride to ferrous chloride in the iron oxide precursor solution is 2:1;

[0130] (7) Add ammonia water dropwise to the carbon-based magnetic hydrogel obtained in step (6) until the pH value is 9. Then wash with ethanol aqueous solution with a mass concentration of 20% until the pH value is 7. Extract the ethanol aqueous solution and finally pre-freeze at -20℃ for 72h and freeze-dry at -40℃ for 72h to obtain carbon-based magnetic aerogel.

[0131] Test Example 12

[0132] (1) Add graphene oxide to distilled water and then perform ultrasonic mixing in an ultrasonic cleaner to obtain a graphene oxide dispersion; the ultrasonic mixing temperature is 25℃, the ultrasonic mixing time is 1h, and the ultrasonic mixing frequency is 40kHz.

[0133] (2) Add dopamine hydrochloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a dopamine hydrochloride solution; the temperature of the magnetic stirring is 60℃, the stirring time is 2h, and the stirring speed is 800r / min.

[0134] (3) Add ferric chloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a ferric chloride solution; the temperature of the magnetic stirring is 50℃, the stirring time is 20min, and the stirring speed is 500r / min; the concentration of the ferric chloride solution is 4mg / mL.

[0135] (4) Add ferrous chloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a ferrous chloride solution; the temperature of the magnetic stirring is 30℃, the stirring time is 20min, and the stirring speed is 800r / min; the concentration of the ferrous chloride solution is 2mg / mL.

[0136] (5) The ferric chloride solution obtained in step (3) and the ferrous chloride solution obtained in step (4) are mixed and first magnetically stirred on a magnetic stirrer, and then ultrasonically mixed in an ultrasonic cleaner to obtain a ferric oxide precursor solution; the magnetic stirring temperature is room temperature, the magnetic stirring time is 20h, and the magnetic stirring speed is 800r / min; the ultrasonic mixing temperature is 25℃, the ultrasonic mixing time is 1h, and the ultrasonic mixing frequency is 35kHz; the mass ratio of ferric chloride to ferrous chloride in the ferric oxide precursor solution is 2:1;

[0137] (6) Add the dopamine hydrochloride solution obtained in step (2) and the iron oxide precursor solution obtained in step (5) to the graphene dispersion obtained in step (1), and then place it in a drying oven for hydrothermal reaction at 75°C for 16 hours to obtain carbon-based magnetic hydrogel; the amount of graphene dispersion is 20 mL, and the concentration of graphene oxide dispersion is 2 mg / mL; the amount of dopamine hydrochloride solution is 20 mL, and the concentration of dopamine hydrochloride solution is 2 mg / mL; the amount of iron oxide precursor solution is 40 mL, and the mass ratio of ferric chloride to ferrous chloride in the iron oxide precursor solution is 2:1;

[0138] (7) Add ammonia water dropwise to the carbon-based magnetic hydrogel obtained in step (6) until the pH value is 9. Then wash with ethanol aqueous solution with a mass concentration of 20% until the pH value is 7. Extract the ethanol aqueous solution and finally pre-freeze at -20℃ for 72h and freeze-dry at -40℃ for 72h to obtain carbon-based magnetic aerogel.

[0139] Test Example 13

[0140] (1) Add graphene oxide to distilled water and then perform ultrasonic mixing in an ultrasonic cleaner to obtain a graphene oxide dispersion; the ultrasonic mixing temperature is 25℃, the ultrasonic mixing time is 1h, and the ultrasonic mixing frequency is 40kHz.

[0141] (2) Add dopamine hydrochloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a dopamine hydrochloride solution; the temperature of the magnetic stirring is 60℃, the stirring time is 2h, and the stirring speed is 800r / min.

[0142] (3) Add ferric chloride to distilled water and then stir magnetically on a magnetic stirrer to obtain a ferric chloride solution; the temperature of the magnetic stirring is 50℃, the stirring time is 20min, and the stirring speed is 500r / min; the concentration of the ferric chloride solution is 6mg / mL.

[0143] (4) Ferrous chloride was added to distilled water and then magnetically stirred on a magnetic stirrer to obtain a ferrous chloride solution; the temperature of the magnetic stirring was 30°C, the stirring time was 20 min, and the stirring speed was 800 r / min; the concentration of the ferrous chloride solution was 3 mg / mL.

[0144] (5) The ferric chloride solution obtained in step (3) and the ferrous chloride solution obtained in step (4) are mixed and first magnetically stirred on a magnetic stirrer, and then ultrasonically mixed in an ultrasonic cleaner to obtain a ferric oxide precursor solution; the magnetic stirring temperature is room temperature, the magnetic stirring time is 20h, and the magnetic stirring speed is 800r / min; the ultrasonic mixing temperature is 25℃, the ultrasonic mixing time is 1h, and the ultrasonic mixing frequency is 35kHz; the mass ratio of ferric chloride to ferrous chloride in the ferric oxide precursor solution is 2:1;

[0145] (6) Add the dopamine hydrochloride solution obtained in step (2) and the iron oxide precursor solution obtained in step (5) to the graphene dispersion obtained in step (1), and then place it in a drying oven for hydrothermal reaction at 75°C for 16 hours to obtain carbon-based magnetic hydrogel; the amount of graphene dispersion is 20 mL, and the concentration of graphene oxide dispersion is 2 mg / mL; the amount of dopamine hydrochloride solution is 20 mL, and the concentration of dopamine hydrochloride solution is 2 mg / mL; the amount of iron oxide precursor solution is 40 mL, and the mass ratio of ferric chloride to ferrous chloride in the iron oxide precursor solution is 2:1;

[0146] (7) Add ammonia water dropwise to the carbon-based magnetic hydrogel obtained in step (6) until the pH value is 9. Then wash with ethanol aqueous solution with a mass concentration of 20% until the pH value is 7. Extract the ethanol aqueous solution and finally pre-freeze at -20℃ for 72h and freeze-dry at -40℃ for 72h to obtain carbon-based magnetic aerogel.

[0147] The carbon-based magnetic aerogels prepared in Test Examples 11-13 were observed by scanning electron microscopy, and the obtained SEM images are shown below. Figure 17 As shown. By Figure 17 It can be seen that when DGA (i.e., graphene oxide): Fe 3+ (i.e., ferric chloride): Fe 2+ When the mass ratio of graphene oxide to ferrous chloride is 2:4:2, the particle size distribution in the carbon-based magnetic aerogel is relatively uniform. However, if the concentration is too low (i.e., 2:2:1), there will be very few particles, and if the concentration is too high (i.e., 2:6:3), agglomeration and encapsulation will occur. Therefore, the concentration of graphene oxide to ferrous chloride to ferrous chloride at a mass ratio of 2:4:2 is selected as the optimal value for carbon-based magnetic aerogel.

[0148] The properties of the carbon-based magnetic aerogel / graphene nylon composite fabric prepared in Example 1 were tested, and electron microscopy was performed. The electron microscopy images are shown below. Figure 18 As shown. According to Figure 18 As can be seen, in the carbon-based magnetic aerogel / graphene nylon composite fabric provided by this invention, graphene is uniformly distributed on the composite fabric, and magnetic particles are also distributed on it, thereby improving the electromagnetic shielding effectiveness of the composite fabric. Electromagnetic shielding effectiveness of the carbon-based magnetic aerogel / graphene nylon composite fabric was tested using the window method described in GJB6190-2008 "Method for Measuring the Shielding Effectiveness of Electromagnetic Shielding Materials". The results showed that the electromagnetic shielding effectiveness of the carbon-based magnetic aerogel / graphene nylon composite fabric at high frequencies was 36.4–48.3 dB, indicating a certain level of electromagnetic shielding effectiveness, far exceeding the application standard of GB / T 26667-2011 for civilian electromagnetic shielding materials.

[0149] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a carbon-based magnetic aerogel / graphene nylon composite fabric, comprising the following steps: (1) The electromagnetic shielding fabric, graphene oxide dispersion, dopamine hydrochloride solution and iron oxide precursor solution are mixed and then subjected to hydrothermal reaction to obtain carbon-based magnetic hydrogel containing the fabric; the electromagnetic shielding fabric is a three-dimensional electromagnetic shielding fabric; the three-dimensional structure of the electromagnetic shielding three-dimensional fabric is layered corner interlocking. (2) The carbon-based magnetic hydrogel containing fabric obtained in step (1) is freeze-dried to obtain carbon-based magnetic aerogel composite fabric. (3) The carbon-based magnetic aerogel composite fabric obtained in step (2) is mixed with an aqueous polyurethane solution and then cured to obtain a carbon-based magnetic aerogel / graphene nylon composite fabric. In step (1), the electromagnetic shielding fabric is woven from graphene nylon filament; the specifications of the graphene nylon filament are 300D / 144F. In step (1), the mass ratio of graphene oxide in the graphene oxide dispersion to dopamine hydrochloride in the dopamine hydrochloride solution is 1:(1~1.5). The method for preparing the iron oxide precursor solution is to mix ferric chloride solution and ferrous chloride solution, stir magnetically, and then mix ultrasonically to obtain the iron oxide precursor solution. In step (1), the mass ratio of graphene oxide in the graphene oxide dispersion and the mass ratio of ferric chloride to ferrous chloride in the iron oxide precursor solution is 2:4:

2.

2. The preparation method according to claim 1, characterized in that, The hydrothermal reaction temperature in step (1) is 70~80℃, and the hydrothermal reaction time is 12~20h.

3. The preparation method according to claim 1, characterized in that, The viscosity of the aqueous polyurethane solution in step (3) is <300 mPa·S.

4. The preparation method according to claim 1, characterized in that, The curing temperature in step (3) is 60~90℃ and the curing time is 6~8h.

5. The carbon-based magnetic aerogel / graphene nylon composite fabric prepared by the preparation method according to any one of claims 1 to 4.

6. The application of the carbon-based magnetic aerogel / graphene nylon composite fabric according to claim 5 in electronic devices.

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