Electromagnetic shielding composite material containing MXene nanosheets impregnated fabric and rubber film and preparation method thereof

Abstract

The present invention discloses an electromagnetic shielding composite material comprising a fabric impregnated with MXene nanosheets and a rubber film, and a preparation method. The electromagnetic shielding composite material comprises an upper layer of impregnated fabric containing MXene nanosheets of varying sizes, and a lower layer of a natural rubber film containing 30% MXene, which are combined by hot pressing. A MXene solution is synthesized by hydrofluoric acid etching, then pulverized by an ultrasonic cell pulverizer and ultracentrifuged to obtain a solution of MXene nanosheets of varying sizes. The solution is then vacuum impregnated with a non-woven fabric to load the MXene of varying sizes onto the fabric. A natural rubber film containing 30% MXene is then prepared, and finally, the impregnated non-woven fabric and the natural rubber film are combined to obtain the electromagnetic shielding composite material. The present invention is thin, lightweight, and flexible. By varying the size of the MXene nanosheets, different conductive fabrics are obtained that meet varying electromagnetic shielding performance requirements. This method utilizes readily available raw materials, exhibits good stability, and features a simple preparation process, making it suitable for large-scale production and promising applications.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding materials, and in particular to an electromagnetic shielding composite material composed of an impregnated fabric containing MXene nanosheets and a rubber film and a preparation method thereof. Background Art

[0002] While the development of electronic information technology promotes social progress, it inevitably generates electromagnetic pollution, which can seriously impact the normal operation of electronic devices and human health. Therefore, research on electromagnetic shielding materials is crucial. Traditional metal materials are characterized by high density, high cost, difficulty in processing, susceptibility to corrosion, and inflexibility, making them inaccessible in today's increasingly integrated and miniaturized electronic components. Therefore, it is necessary to explore electromagnetic shielding materials with low density, good flexibility, thin thickness, and simple fabrication processes. Electromagnetic shielding fabrics are widely used in wearable devices due to their flexibility, thinness, light weight, good conductivity, and simple fabrication processes. However, traditional electromagnetic shielding fabrics are typically produced by electroplating or coating metal materials onto fabrics or blending them with fabrics. These materials have disadvantages such as high density, high cost, complex fabrication processes, and susceptibility to corrosion, which limit their application. Conductive polymer composites (CPCs), which use conductive materials as fillers and polymers as matrices, are considered ideal alternative EMI shielding materials for next-generation smart protective devices due to their light weight, low cost, corrosion resistance, and good processability. MXene (McKessen) is a new class of two-dimensional transition metal carbides or nitrides that has attracted widespread attention due to its unique two-dimensional layered structure, high electrical and thermal conductivity, and flexibility. Recently, Faisal Shahzad et al. have demonstrated that MXene and its composites exhibit excellent electromagnetic interference shielding properties, reaching 92 dB at 42 microns within the X-band frequency range (8.2-12.4 GHz), demonstrating promising applications in advanced smart electronics. Furthermore, MXene is hydrophilic, offering advantages in polymer bonding. However, pure MXene has relatively poor mechanical properties and is susceptible to oxidation. Therefore, developing an electromagnetic shielding material that is lightweight, thin, flexible, and simple to prepare is crucial.

[0003] The present invention uses MXene nanosheets of different sizes, large, medium and small, as fillers and composites them with natural rubber to produce multiple rubber films with different MXene contents. Rubber films with excellent flexibility, stretchability and electromagnetic shielding performance are then selected and combined with impregnated fabrics to produce a double-layer composite material with excellent flexibility and electromagnetic shielding performance. The electromagnetic shielding performance of the upper conductive fabric can be further adjusted and improved by changing the size of the MXene. In the absence of an external adhesive, the rubber film and fabric are combined together to form a double-layer structure by utilizing the adhesiveness of natural rubber itself. With only a certain increase in thickness, the electromagnetic shielding performance is greatly improved, and the double-layer structure further improves the flexibility of the overall material.

[0004] This electromagnetic shielding composite material, composed of a MXene-containing rubber membrane and fabric, uses MXene as a filler, providing high conductivity, while the fabric and natural rubber matrix provide excellent flexibility and stretchability. The underlying rubber membrane exhibits a degree of elasticity and compressibility, providing excellent support for the conductive fabric and a spacer, offering enhanced installability and suitability for wearable electromagnetic shielding applications. The resulting composite material is lightweight, thin, and flexible. Its multilayered structure improves impedance matching, primarily by absorbing losses, resulting in an overall electromagnetic shielding performance of 93dB, making it suitable for wearable electromagnetic shielding applications. Summary of the Invention

[0005] In response to the problems existing in the existing methods, the present invention proposes an electromagnetic shielding composite material composed of an impregnated fabric containing MXene nanosheets and a rubber film and a preparation method thereof. The composite material is composed of an upper layer of an impregnated fabric containing MXene nanosheets of different sizes and a lower layer of a natural rubber film with a MXene content of 30%, which are combined by hot pressing in any combination.

[0006] A) The impregnated fabric containing MXene nanosheets of different sizes was prepared by the following method:

[0007] 1) Etching: Use a pipette to take 3-60 ml of deionized water into a plastic bottle (turn on the magnetic stirrer to start stirring and set the oil bath temperature to 30-40°C), add 6-120 ml of HCl, then add 1.25-25 ml of HF, then weigh 0.5-10 g of Ti3AlC2 and add it to the plastic bottle in 3-8 times, and etch for 24 hours.

[0008] 2) Cleaning 1: Centrifuge the etched mixture at 5000 r / min for 3 minutes, retain the precipitate, add 30-45 ml of deionized water and shake well, continue centrifugation and washing for 5-10 times until the solution becomes neutral.

[0009] 3) Intercalation: Weigh 0.5-10g LiCl and pour it into a plastic bottle (turn on the magnetic stirrer to start stirring and set the oil bath temperature to 30-40°C), then add 30-600ml deionized water (rinse the MXene and water into the plastic bottle together), and intercalate for 4h.

[0010] 4) Wash 2: After intercalation, centrifuge at 5000 r / min for 2 minutes, retain the precipitate, add 30-45 ml of deionized water and shake well. Continue centrifugation twice, then centrifuge at 8000 r / min for 3 minutes. Retain the precipitate and add 30-45 ml of deionized water and shake well (ultrasound will break the MXene nanosheets, shaking by hand is more gentle and the obtained MXene is of higher quality). Continue centrifugation at 3500 r / min for 2 minutes, remove the upper layer solution to a clean test tube and place it in the refrigerator for later use. Prepare a solution with a MXene concentration of 10 mg / ml. This yields a medium-sized MXene nanosheet solution (B), with a medium size range of d = 2-5 μm.

[0011] 5) Take 40 ml of the nanosheet solution (B) prepared in step A) 4) and continue centrifuging at 5000-8000 r / min for 5-10 min. Take the lower precipitate (the MXene nanosheets in the lower precipitate are larger) to obtain a large-sized MXene nanosheet solution (C). 8-15 μm

[0012] 6) Take 40 ml of the (B) nanosheet solution prepared in step A) 4) and crush it in an ultrasonic cell crusher (put the MXene solution beaker into ice cubes for crushing, and cool it down to slow down oxidation). The crusher is operated at 200-400W power for 10-60 minutes to obtain small-sized MXene nanosheet solution (A) 0.1-0.5 μm

[0013] The size of MXene nanosheets is changed by ultrasonic cell crusher crushing and ultracentrifugation, and larger MXene nanosheets are used to improve the absorption loss and overall electromagnetic shielding properties of MXene-based conductive fabrics.

[0014] B) Preparation of impregnated fabrics containing MXene nanoparticles of different sizes

[0015] 1. Take several pieces of non-woven fabric, wash them repeatedly with anhydrous ethanol and dry them:

[0016] 2. Take 20 ml of the medium-sized nanosheet solution (B) obtained in step A) 4) and impregnate non-woven fabrics (the fabric material is cotton fabric, polyester fabric, polyester-cotton fabric, polyurethane and cellulose mixed non-woven fabric, preferably, the fabric material is polyurethane and cellulose mixed non-woven fabric). The fabric is vacuum impregnated in a vacuum box for 10-30 minutes, and then vacuum dried for 1-6 hours at a drying temperature of 40-60°C. The impregnation and drying process is repeated 1-15 times. An impregnated fabric containing medium-sized MXene nanosheets is obtained. This is called type (B) impregnated fabric.

[0017] 2. Take 20 ml of the large-sized nanosheet solution (C) in step A) 5) and impregnate non-woven fabrics (the fabric material is cotton fabric, polyester fabric, polyester-cotton fabric, polyurethane and cellulose mixed non-woven fabric, preferably, the fabric material is polyurethane and cellulose mixed non-woven fabric). The fabric is vacuum impregnated in a vacuum box for 10-30 minutes, and then vacuum dried for 1-6 hours at a drying temperature of 40-60°C. The impregnation and drying process is repeated 1-15 times. An impregnated fabric containing large-sized MXene nanosheets is obtained. It is called type (C) impregnated fabric.

[0018] 3. Take 20 ml of the small-sized nanosheet solution (A) in step A) 6) and impregnate non-woven fabrics (the fabric material is cotton fabric, polyester fabric, polyester-cotton fabric, polyurethane and cellulose mixed non-woven fabric, preferably, the fabric material is polyurethane and cellulose mixed non-woven fabric). The fabric is vacuum impregnated in a vacuum box for 10-30 minutes, and then vacuum dried for 1-6 hours at a drying temperature of 40-60°C. The impregnation and drying process is repeated 1-15 times. An impregnated fabric containing small-sized MXene nanosheets is obtained. It is called type (A) impregnated fabric.

[0019] C) Preparation of natural rubber film with 30% MXene content

[0020] Take 0.1-30 ml of the (B) nanosheet solution prepared in step A) 4), take 1-10 ml of natural latex with a concentration of 5-60 mg / ml, and calculate the MXene content to be 30%, mix the two on a magnetic stirrer and stir for 10-60 minutes, then vacuum filter, and vacuum dry the filtered membrane in a vacuum oven at 10-40°C for 1-4 hours, then peel off the filter paper to obtain a natural rubber membrane with a MXene content of 30%.

[0021] D) Hot Pressing Combination All types of impregnated fabrics described in step B) are hot pressed together with the natural rubber combination with a MXene content of 30% described in the step to form the electromagnetic shielding composite material of the present invention.

[0022] Alternatively, the impregnated fabric (B), the impregnated fabric (C), the impregnated fabric (A) in step B) and the natural rubber film with a MXene content of 30% in step C) are combined by hot pressing in any combination to form a

[0023] The electromagnetic shielding composite material of the present invention.

[0024] The advantages of the present invention are that the electromagnetic shielding composite material of the present invention is thin, light and bendable. The electromagnetic shielding performance of the conductive fabric obtained by changing the size of the MXene nanosheets reaches 78dB, and the electromagnetic shielding performance of the constructed double-layer structure of fabric and rubber film is as high as 93dB, which far meets the commercial requirement of 20dB.

[0025] The double-layer structure of the present invention, with its lower layer of natural rubber providing excellent elasticity and supporting the upper fabric layer, offers excellent installability and is well-suited for use as gaskets for electronic components and in wearable electromagnetic shielding applications. This method utilizes readily available raw materials, exhibits excellent stability, and features a simple preparation process, making it suitable for large-scale production and promising broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Digital photographs of electromagnetic shielding composite materials composed of a multilayer rubber film containing MXene and fabric, where a is the natural rubber film on the back, b is the conductive fabric on the front, c is the side view, and d is the bending view of the composite material. It can be seen that the rubber film and fabric are very well combined, and the thickness is thin and the bending flexibility is good.

[0027] Figure 2 XRD energy spectra of electromagnetic shielding composite materials composed of multilayer rubber films and fabrics containing MXene, where a is the XRD energy spectrum of non-woven fabric and MXene-based conductive fabric, and b is the XRD energy spectrum of MXene, natural rubber, and MXene-natural rubber composite film.

[0028] Figure 3 This bar chart shows the overall electromagnetic shielding performance of nonwoven fabrics impregnated with MXene nanosheet solutions of varying sizes. As the size increases and the number of impregnations increases, the overall electromagnetic shielding performance of the conductive fabric improves, reaching as high as 78 dB. Larger sizes significantly improve overall electromagnetic shielding performance.

[0029] Figure 4 The electromagnetic shielding performance of non-woven fabrics impregnated with MXene nanosheet solutions of different sizes is shown in the figure. It can be seen that as the size increases and the number of impregnations increases, the reflection loss increases. Larger sizes have a positive effect on the reflection loss.

[0030] Figure 5The absorption loss and electromagnetic shielding performance of non-woven fabrics impregnated with MXene nanosheet solutions of different sizes are shown in the figure. It can be seen that the absorption loss increases with increasing size and the number of impregnations. Larger sizes have a positive effect on absorption loss.

[0031] Figure 6 The electromagnetic shielding performance of small size (A) impregnated fabric at 8.2-12.4GHz is shown in the figure. It can be seen that the electromagnetic shielding effect increases in the frequency range of 8.2-12.4GHz with the increase of the number of impregnations.

[0032] Figure 7 The electromagnetic shielding performance of the medium-sized (B) impregnated fabric at 8.2-12.4 GHz is shown in the figure. It can be seen that the electromagnetic shielding effect increases in the frequency range of 8.2-12.4 GHz with the increase of the number of impregnations.

[0033] Figure 8 The electromagnetic shielding performance of large-size (C) impregnated fabric at 8.2-12.4GHz is shown in the figure. It can be seen that the electromagnetic shielding effect increases in the frequency range of 8.2-12.4GHz with the increase of the number of impregnations.

[0034] Figure 9 Figure 2 is the electromagnetic shielding performance diagram of natural rubber film containing MXene; a is the electromagnetic shielding bar graph of natural rubber film with different MXene contents (SER is reflection loss, SEA is absorption loss, and SET is total electromagnetic shielding loss. b is the electromagnetic shielding performance dot-line graph of different MXene contents in the frequency range of 8.2-12.4 GHz. It can be seen that with the increase of MXene content, the electromagnetic shielding performance is improved, up to 75 dB.

[0035] Figure 10 Graphs depicting the electromagnetic shielding performance of electromagnetic shielding composite materials composed of multilayer rubber films containing MXene and fabrics: a) a bar graph showing the electromagnetic shielding performance of composite materials composed of natural rubber films containing 30% MXene and conductive fabrics impregnated with different numbers of impregnations; and d) a dot-line graph showing the electromagnetic shielding performance of composite materials composed of MXene-based natural rubber films and conductive fabrics in the 8.2-12.4 GHz frequency range. It can be seen that the composite material, composed of a rubber film containing 30% MXene and conductive fabric impregnated ten times, achieves a total electromagnetic shielding performance as high as 93 dB. The MXene-based natural rubber film-conductive fabric electromagnetic shielding composite material of the present invention exhibits excellent electromagnetic shielding performance while maintaining low density, thinness, and high flexibility, making it well-suited for wearable applications. DETAILED DESCRIPTION

[0036] Example 1

[0037] Preparation of MXene nanosheet solutions of different sizes:

[0038] 1) Etching: Place the plastic bottle in a 35°C oil bath and start magnetic stirring. Take 12ml of deionized water, 24ml of hydrochloric acid, and 5ml of hydrofluoric acid in the plastic bottle respectively. Then weigh 2g of Ti3AlC2 precursor and slowly pour it into the plastic bottle. Cover the bottle cap and etch for 24 hours. Pour the etched solution into two centrifuge tubes, add 45ml of deionized water, shake well, centrifuge at 5000r / min for 3 minutes, and repeat centrifugation and washing 5 times. When the pH is neutral with pH test paper, stop centrifugation and washing, discard the supernatant and retain the precipitate.

[0039] 2) Intercalation: First weigh 2g of lithium chloride into a plastic bottle in a 35℃ oil bath and start magnetic stirring. Then use 120ml of deionized water to rinse the precipitate after etching and washing in 1) into the plastic bottle, cover the bottle cap, and intercalate for 4 hours. The intercalated solution is poured into two centrifuge tubes, centrifuged at 5000r / min for 2min, retain the precipitate, add 45ml of deionized water and shake well, continue centrifugation 2 times, and then centrifuge at 8000r / min for 3min, retain the precipitate, add 45ml of deionized water and shake well, and continue to centrifuge.

[0040] Centrifuge at 3500 rpm for 2 minutes. Pour the supernatant into a clean test tube and refrigerate until ready for use. (Hand-shaking the pellet is gentler than conventional ultrasonic vibration.) Prepare a MXene solution with a concentration of 10 mg / ml. This yields a medium-sized MXene nanosheet solution (B), with a median size range of d = 2-5 μm.

[0041] 3) Take 40 ml of the nanosheet solution (B) prepared in step 2), continue centrifuging at 8000 r / min for 10 min, take the lower precipitate (the size of the MXene nanosheets in the lower precipitate is larger), and obtain a large-sized MXene nanosheet solution (C).

[0042] 8-15μm

[0043] Take 40 ml of the (B) nanosheet solution prepared in step 2) and crush it in an ultrasonic cell crusher (put the MXene solution beaker into ice cubes for crushing, and cool it down to slow down oxidation). The crusher works at 400 W power for 30 minutes to obtain small-sized MXene nanosheet solution (A) 0.1-0.5 μm

[0044] Example 2

[0045] Conductive fabrics were prepared using solutions containing MXene nanosheets of different sizes:

[0046] 1) Place 20 ml of B synthesized in 2) and A and C synthesized in 3) (10 mg / ml) in a small beaker and immerse the nonwoven fabric in each of these solutions. Place the beaker in a vacuum drying oven, evacuate for 10 minutes, remove, and vacuum dry in a drying oven at 50°C for 2 hours. Repeat this process for n (n = 1, 2, 5, 10) impregnations. Conductive fabrics with varying MXene sizes and loadings were obtained.

[0047] Example 3

[0048] Preparation of natural rubber composite membrane containing MXene:

[0049] Take 0.1-30ml of the (B) nanosheet solution prepared in step 2) and prepare 30mg / ml of natural latex with a solid content of 64%. Take 0.67ml, 1.5ml, 2.57ml, 4ml, 6ml, and 9ml of the 10mg / ml MXene solution in a beaker and stir with a magnetic stirrer. Then, take 2ml, 2ml, 2ml, 2ml, 2ml of natural latex with a concentration of 30mg / ml and add it to the beaker containing different amounts of MXene solution and stir magnetically for 30 minutes. The mixed solution is vacuum filtered and the filtered membrane is placed in a vacuum drying oven at 60℃ for 2 hours. After that, the filter paper is removed to obtain MXene natural rubber composite membranes with different MXene contents N (N = 10%, 20%, 30%, 40%, 50%, 60%). The composite membrane with 30% MXene content has better flexibility, stretchability, and bendability. The composite membrane with 30% MXene content is preferred for the following studies.

[0050] Example 4

[0051] Electromagnetic shielding composite materials composed of multilayer rubber films and fabrics containing MXene:

[0052] 1) Following the method and proportions described in Example 2, the fabric was impregnated with the large-size MXene solution (C) n times (n = 1, 2, 5, 10) to obtain four impregnated fabrics. The difference was that the conductive fabric was not vacuum-dried after the final impregnation, but remained moist.

[0053] 2) A composite membrane with a 30% MXene content was preferably prepared according to the method and ratio in Example 3, except that the filtration was stopped when the MXene natural latex membrane was still wet.

[0054] 3) Align and press four wet conductive fabrics onto the wet MXene natural rubber composite film, press them gently, and dry them in a drying oven at 60°C for 2 hours to obtain a MXene-based natural rubber film combined with a conductive fabric electromagnetic shielding composite material.

[0055] The electromagnetic shielding performance of the material obtained above was tested. The test results are shown in the attached figure. The electromagnetic shielding performance of the prepared composite material is as high as 93dB. It is also light in weight, thin in thickness, and has good flexibility and can be bent repeatedly.

Claims

1. A method for preparing an electromagnetic shielding composite material comprising a fabric impregnated with MXene nanosheets and a rubber film, comprising the following steps: A) Preparation of solutions containing MXene nanosheets of different sizes: 1) Etching: Use a pipette to take 3-60ml of deionized water into a plastic bottle, turn on the magnetic stirrer to start stirring, set the oil bath temperature to 30-40℃, add 6-120ml HCl and 1.25-25ml HF, then weigh 0.5-10g Ti3AlC2 and add it to the plastic bottle in 3-8 times, and etch for 24h; 2) Cleaning 1: Centrifuge the etched mixture at 5000r / min for 3 minutes, discard the upper clear layer, retain the precipitate, add 30-45ml of deionized water and shake well, continue centrifugation and washing for 5-10 times until the solution becomes neutral; 3) Intercalation: Weigh 0.5-10g LiCl and pour it into a plastic bottle. Turn on the magnetic stirrer to start stirring. Set the oil bath temperature to 30-40℃. Then add 30-600ml deionized water and intercalate for 4h. 4) Cleaning 2: After intercalation, centrifuge at 5000 r / min for 2 minutes, retain the precipitate, add 30-45 ml of deionized water and shake well, continue centrifugation twice, then centrifuge at 8000 r / min for 3 minutes, retain the precipitate, add 30-45 ml of deionized water and shake well by hand, continue centrifugation at 3500 r / min for 2 minutes, take the upper layer solution into a clean test tube and put it in the refrigerator for later use, and prepare a solution with a MXene concentration of 10 mg / ml to obtain a medium-sized MXene nanosheet solution (B), with a medium size range of d = 2-5 μm; 5) Take 40 ml of the medium-sized MXene nanosheet solution (B) prepared in step A) 4) and continue centrifuging at 5000-8000 rpm for 5-10 min. Remove the lower precipitate to obtain a large-sized MXene nanosheet solution (C). The large-sized MXene nanosheets have a size range of d = 8-15 μm. 6) Take 40 ml of the medium-sized MXene nanosheet solution (B) prepared in step A) 4) and crush it in an ultrasonic cell crusher in an ice bath environment. The crusher operates at a power of 200-400 W for 10-60 minutes to obtain a small-sized MXene nanosheet solution (A). The small-sized MXene nanosheets have a size range of d = 0.1-0.5 μm; B) Preparation of impregnated fabrics containing MXene nanosheets of different sizes:

1. Take several pieces of non-woven fabric, wash them repeatedly with anhydrous ethanol and dry them; 2. Take 20 ml of the medium-sized MXene nanosheet solution (B) obtained in step A) 4) and impregnate a non-woven fabric under vacuum in a vacuum chamber for 10-30 minutes, followed by vacuum drying for 1-6 hours at a temperature of 40-60°C. Repeat the impregnation and drying process 1-15 times to obtain an impregnated fabric containing medium-sized MXene nanosheets, referred to as type (B) impregnated fabric.

3. Take 20 ml of the large-sized MXene nanosheet solution (C) obtained in step A) 5) and impregnate a non-woven fabric under vacuum in a vacuum chamber for 10-30 minutes, followed by vacuum drying for 1-6 hours at a temperature of 40-60°C. Repeat the impregnation and drying process 1-15 times to obtain an impregnated fabric containing large-sized MXene nanosheets, referred to as type (C) impregnated fabric.

4. Take 20 ml of the small-sized MXene nanosheet solution (A) obtained in step A) 6) and impregnate a non-woven fabric under vacuum in a vacuum chamber for 10-30 minutes, followed by vacuum drying for 1-6 hours at a temperature of 40-60°C. Repeat the impregnation and drying process 1-15 times to obtain an impregnated fabric containing small-sized MXene nanosheets, referred to as type (A) impregnated fabric. C) Preparation of natural rubber membrane with 30% MXene content: Take 0.1-30 ml of the medium-sized MXene nanosheet solution (B) prepared in step A) 4) and 1-10 ml of natural latex with a concentration of 5-60 mg / ml, and calculate the MXene content to be 30%. Mix the two on a magnetic stirrer and stir for 10-60 minutes. Then vacuum filter the filtered membrane and dry it in a vacuum oven at 10-40°C for 1-4 hours. Then peel off the filter paper to obtain a natural rubber membrane with a 30% MXene content. D) Hot pressing combination: One of the impregnated fabrics (A), (B) and (C) described in step B) and the natural rubber film with a MXene content of 30% described in step (C) are combined by hot pressing to form an electromagnetic shielding composite material.

2. The method for preparing the electromagnetic shielding composite material of the impregnated fabric containing MXene nanosheets and the rubber film according to claim 1, characterized in that: In step B), the non-woven fabric is made of a mixture of polyurethane and cellulose.

3. An electromagnetic shielding composite material comprising an impregnated fabric containing MXene nanosheets and a rubber film, characterized in that: The electromagnetic shielding composite material comprising an impregnated fabric and a rubber film containing MXene nanosheets is prepared according to the method for preparing an electromagnetic shielding composite material comprising an impregnated fabric and a rubber film containing MXene nanosheets as claimed in claim 1 or 2.

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