Preparation method and application of high-permeability cellulose-based electromagnetic shielding composite film

Abstract

The invention belongs to the technical field of electromagnetic protection materials, and particularly discloses a preparation method of a high-permeability cellulose-based electromagnetic shielding composite film, which comprises the following steps: S1) sequentially etching and concentrating an MXene suspension to obtain few layers of MXene; s2) carrying out acetalation reaction on polyvinyl alcohol to obtain catechol modified polyvinyl alcohol; s3) carrying out free radical polymerization on the cellulose to obtain grafted poly (acryloyloxyethyl) trimethyl ammonium chloride cellulose; and S4) dispersing the grafted polyacryloyloxyethyl trimethyl ammonium chloride cellulose, depositing the dispersed grafted polyacryloyloxyethyl trimethyl ammonium chloride cellulose on a filter membrane to form modified cellulose filter paper, mixing catechol modified polyvinyl alcohol with few layers of MXene, depositing the mixed material on the modified cellulose filter paper, and performing hot-pressing deposition to obtain the composite film. S5, the composite film is soaked in a metal salt solution and then dried, laser drilling is conducted, and then the high-permeability cellulose-based electromagnetic shielding composite film is obtained.The high-permeability cellulose-based electromagnetic shielding composite film is obtained.The raw material cost is low, the manufacturing process is simple, and the high-permeability cellulose-based electromagnetic shielding composite film has huge application prospects in the aspect of electromagnetic protection of flexible wearable electronic equipment.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic shielding materials in the electromagnetic protection of flexible wearable electronic devices, and particularly to a method for preparing a high-permeability cellulose-based electromagnetic shielding composite film. Background Technology

[0002] In recent years, with the rapid development of mobile communication technology and flexible electronic materials, the operation of wireless communication modules inevitably generates electromagnetic interference and radiation. This not only affects the normal operation of electronic devices but may also pose a potential threat to human physical and mental health. Cellulose-based electromagnetic shielding composite films are lightweight, thin, have good mechanical properties, are highly designable, and have good biocompatibility, making them the preferred material for electromagnetic shielding protection of wearable electronic devices. However, the good hydrophilicity and biocompatibility of the cellulose matrix can easily lead to bacterial growth and biocontamination, causing discomfort issues such as allergies and inflammation. Therefore, the research and preparation of corresponding high-performance electromagnetic shielding materials is urgent. Cellulose is a naturally occurring biopolymer material with high strength, high modulus, good flexibility and stability, as well as advantages such as low density and renewability. MXene is a novel transition metal carbide and nitride with a two-dimensional layered structure. It has good conductivity, hydrophilicity, high specific surface area, and abundant oxygen-containing functional groups (-OH, -O, etc.), and easily forms hydrogen bonds with cellulose molecules. As a conductive filler, it can be widely used in the field of electromagnetic shielding. Composite films prepared using cellulose paper as the matrix and MXene as the conductive filler can effectively solve the electromagnetic interference problem in current electronic devices.

[0003] Composite films prepared using cellulose paper as the matrix and MXene as the conductive filler can effectively solve the electromagnetic interference problem in current electronic devices. However, MXene / cellulose composite films are usually dense in structure and have poor permeability, hindering the transmission of monitored objects from the skin to the upper sensor of wearable electronic devices, thus interfering with the sensor's monitoring sensitivity. Simultaneously, the good hydrophilicity and biocompatibility of the cellulose matrix easily lead to bacterial growth and biocontamination, causing wearability discomfort issues such as allergies and inflammation. Therefore, developing cellulose-based electromagnetic shielding composite films and comprehensively and deeply studying the synergistic optimization of their mechanical properties, electromagnetic shielding effectiveness, and permeability, while simultaneously addressing the bacterial growth problem, is of great practical significance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing an electromagnetic shielding composite film containing highly permeable cellulose-based material, which has excellent antibacterial properties, mechanical properties, permeability and electromagnetic shielding properties, as well as flexibility and long service life.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions.

[0006] A method for preparing a high-permeability cellulose-based electromagnetic shielding composite film includes the following steps:

[0007] S1) The MXene suspension was sequentially etched and concentrated to obtain a few-layer MXene;

[0008] S2) Polyvinyl alcohol is modified with catechol by acetalization.

[0009] S3) Cellulose free radical polymerization yields grafted polyacryloxyethyltrimethylammonium chloride cellulose;

[0010] S4) Grafted polyacryloxyethyltrimethylammonium chloride cellulose is dispersed and deposited on the filter membrane to form modified cellulose filter paper. Catechol-modified polyvinyl alcohol is mixed with few-layer MXene and deposited on the modified cellulose filter paper. The composite film is obtained by hot pressing deposition.

[0011] The mass ratio of cellulose:MXene:modified polyvinyl alcohol is from 50:2:1 to 10:2:1;

[0012] S5) The composite film is soaked in a metal salt solution, dried, and then laser-drilled to obtain an electromagnetic shielding composite film containing high-permeability cellulose-based material.

[0013] Furthermore, the MXene suspension is prepared using a LiF-HCl system, wherein the LiF-HCl system is at least Ti3C2T. X Solution, Ti3N2T X Solution, Ti3CNT X Solution or Ti2CT X One of the components in a solution.

[0014] Furthermore, the cellulose free radical polymerization in step S3) includes cellulose silanization modification and free radical combination of silanized cellulose with polyacryloxyethyltrimethylammonium chloride.

[0015] Furthermore, the cellulose alkylation modification specifically involves impregnating a cellulose matrix with a compound containing hydrolyzable silane groups and vinyl groups.

[0016] Further, the combination specifically involves immersing alkylated modified cellulose in a mixed aqueous solution containing a polymerizable double bond quaternary ammonium salt monomer and an initiator with a mass fraction of 20%-40%, and then carrying out a free radical polymerization reaction at 70-100℃ for 2-5 h. After washing with deionized water multiple times, the cellulose is dried at 50-80℃ to constant temperature to obtain grafted polyquaternary ammonium salt cellulose (Cellulose-g-PDAC).

[0017] Further, in step S3), the suspension of few-layer MXene and the modified polyvinyl alcohol aqueous solution with a mass fraction of 6% are mixed at a mass ratio of 2:1 and stirred evenly.

[0018] Furthermore, in step S4), the hot pressing temperature is 70-100℃ and the pressure is 1-5 MPa.

[0019] Further, in step S5), the metal salt solution is at least one of copper chloride solution, ferric chloride hexahydrate solution, or calcium chloride solution.

[0020] Furthermore, in step S5), the diameter of the laser-drilled hole is 15 μm.

[0021] On the other hand, the preparation method of the high-permeability cellulose-based electromagnetic shielding composite film, the application of the prepared high-permeability cellulose-based electromagnetic shielding composite film in electromagnetic shielding protection of wearable electronic devices.

[0022] The beneficial effects of this invention are as follows:

[0023] The highly permeable cellulose-based electromagnetic shielding composite film of this invention uses cellulose as a matrix grafted with polyacryloxyethyltrimethylammonium chloride. Modified cellulose and a uniformly mixed few-layer MXene and modified polyvinyl alcohol are deposited sequentially through vacuum-assisted filtration, followed by hot pressing, and finally metal ion strengthening and laser drilling. This material exhibits excellent antibacterial properties, mechanical properties, permeability, and electromagnetic shielding, while also possessing flexibility and a long service life. The raw materials used in this invention are inexpensive, and the preparation process is simple, thus it has great application potential in the field of electromagnetic shielding protection for wearable electronic devices.

[0024] This invention achieves a coordinated optimization of high permeability and electromagnetic shielding performance by employing laser drilling technology and adjusting the number of holes. Attached Figure Description

[0025] Figure 1a The tensile stress-strain curves of the C / M / P composite materials prepared in Examples 1-5 are shown.

[0026] Figure 1b A comparison chart of the maximum tensile strength of the C / M / P composite materials prepared in Examples 1-5;

[0027] Figure 1c This is a comparison chart of the electrical conductivity of the C / M / P composite materials prepared in Examples 1-5;

[0028] Figure 1d This is a comparison graph showing the changes in electromagnetic shielding effectiveness of the C / M / P composite materials prepared in Examples 1-5 at different frequencies;

[0029] Figure 1e The graph shows a comparison of the electromagnetic shielding effectiveness of the C / M / P composite materials prepared in Examples 1-5.

[0030] Figure 1f This is a comparison chart of the A and R coefficients of the C / M / P composite materials prepared in Examples 1-5;

[0031] Figure 2a The C / M / P / Ca prepared in Example 6 2+ Distribution diagram of Ti element in the cross-section of the composite material;

[0032] Figure 2b The C / M / P / Ca prepared in Example 6 2+ Distribution diagram of Ca element in the cross section of composite material;

[0033] Figure 2c The C / M / P / Ca prepared in Example 6 2+ -5 Shielding effectiveness of composite materials SE T Comparison chart;

[0034] Figure 2d The C / M / PS and C / M / P / Ca prepared in Example 6 2+ -5 The reflection loss of the composite material SE R and absorption loss SE A Comparison image; 2D

[0035] Figure 2e The C / M / P / Ca prepared in Example 6 2+ -5 Shielding effectiveness of composite material before and after 1000 bends (SE) T Comparison chart;

[0036] Figure 2f The C / M / P / Ca prepared in Example 6 2+ -5 C / M / P / Ca of composite material before and after 1000 bending cycles 2 + -5 Composite Material Reflection Loss SE R and absorption loss SE A Comparison chart;

[0037] Figure 2g The C / M / P / Ca prepared in Example 6 2+ Comparison of XRD changes of the -5 composite material in the initial state, 10 days, 20 days, 30 days and 60 days;

[0038] Figure 2h The C / M / P / Ca prepared in Example 62+ Comparison of electromagnetic shielding effectiveness of the composite material at different frequencies after being placed in the initial state, 10 days, 20 days, 30 days and 60 days;

[0039] Figure 2i The C / M / P / Ca prepared in Example 6 2+ Comparison of electromagnetic shielding effectiveness of the -5 composite material in the initial state, after 10 days, 20 days, 30 days, and 60 days;

[0040] Figure 2j The C / M / P / Ca prepared in Example 6 2+ A comparison chart of the changes in A and R coefficients of the -5 composite material in the initial state, 10 days, 20 days, 30 days, and 60 days;

[0041] Figure 2k Cellulose, Cellulose-g-PDAC, and C / M / P / Ca were prepared in Example 6. 2+ -5 Comparison of antibacterial properties against Staphylococcus aureus;

[0042] Figure 2l Cellulose, Cellulose-g-PDAC, and C / M / P / Ca were prepared in Example 6. 2+ -5 Comparison of the antibacterial rate of Staphylococcus aureus;

[0043] Figure 2m The Cellulose-g-PDAC and C / M / P / Ca prepared in Example 6 2+ -5 Comparison of penetration shielding efficiency under different pore numbers in the same area;

[0044] Figure 2n The Cellulose-g-PDAC and C / M / P / Ca prepared in Example 6 2+ -5 Shielding effectiveness at different numbers of apertures (SE) T Absorption loss SE A and reflection loss SE R Comparison chart;

[0045] Figure 2o The Cellulose-g-PDAC and C / M / P / Ca prepared in Example 6 2+ -5 Comparison of water vapor transmission rate under different pore numbers;

[0046] Figure 3a This is a schematic diagram of the structure of the MXene layer of the ion-reinforced C / M / P composite material prepared in Examples 6-8;

[0047] Figure 3b The tensile stress-strain curves of the C / M / P composite materials prepared in Examples 6-8 after coordination with different ions are shown.

[0048] Figure 3c This is a comparison of the maximum tensile strength of the C / M / P composite materials prepared in Examples 6-8 with different ion coordinations;

[0049] Figure 3d A comparison of the electrical conductivity of the C / M / P composite materials prepared in Examples 6-8 after coordination with different ions. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0051] The method for preparing the high-permeability cellulose-based electromagnetic shielding composite film in this embodiment is characterized by comprising the following steps:

[0052] The first step is to prepare few-layer MXene using MXene suspension.

[0053] First, under ice bath conditions, 40 mL of dilute hydrochloric acid with a concentration of approximately 36 wt% (i.e., a concentration percentage of approximately 36%) and deionized water were mixed thoroughly in a polytetrafluoroethylene beaker at a volume ratio of 3:1. Then, 2 g of LiF powder was added, and the mixture was stirred for a certain period of time until homogeneous. Next, 2 g of Ti3AlC2 precursor was weighed and slowly added to the prepared system. After the addition was complete, the beaker was transferred to a 35°C environment and the reaction was allowed to proceed for 24 h. After the reaction was complete, the reaction solution was washed multiple times with deionized water by centrifugation at 3500 rpm until neutral. After multiple washings and shaking, a dark green suspension was collected. The collected suspension was then concentrated at 10000 rpm for subsequent use.

[0054] In this embodiment, the suspension is collected at a low speed of 3500 rpm to separate MXene nanosheets from the reaction waste liquid, while avoiding the agglomeration or sedimentation of nanosheets caused by high-speed centrifugation. The suspension is concentrated at a high speed of 10000 rpm to rapidly enrich the MXene nanosheets in the suspension to obtain a high-concentration MXene suspension.

[0055] The second step is the preparation of catechol-modified polyvinyl alcohol.

[0056] 1 g of polyvinyl alcohol (PVA) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) at 80°C. 25 mg of p-toluenesulfonic acid monohydrate (TsOH) and 75 mg of 3,4-dihydroxybenzaldehyde (DBA) were weighed and added to the cooled PVA solution. After addition, the system was protected under nitrogen atmosphere and reacted at 80°C for 12 h. After the reaction was complete, the precipitate was formed in acetone and washed several times. The purified precipitate was then vacuum dried in an oven at 45°C for 30 min. After drying, the solid was dissolved in deionized water at 90°C to a concentration of 6%.

[0057] The third step is the preparation of grafted polyacryloxyethyltrimethylammonium chloride cellulose.

[0058] Filter paper was cut to a suitable size and then impregnated in 8% 3-(isobutenoyloxy)propyltrimethoxysilane. The solvent system contained 95% ethanol, 1% acetic acid, and 4% deionized water. The mixture was silanized at a constant temperature of 25°C for 1 h. After treatment, the filter paper was thoroughly washed with deionized water. The silanized cellulose filter paper was then immersed in a mixed aqueous solution containing 30 wt% acryloyloxyethyltrimethylammonium chloride (DAC) and 2 g·L⁻¹ potassium persulfate, and subjected to free radical polymerization at 80°C for 3 h to obtain cellulose filter paper grafted with PDAC (Cellulose-g-PDAC). Cellulose-g-PDAC was washed repeatedly with deionized water and dried at 70°C to constant weight.

[0059] The fourth step is the preparation of C / M / P composite materials.

[0060] 0.15 g Cellulose-g-PDAC was dispersed in 50 mL of deionized water. After the reaction was complete, the homogeneous modified cellulose suspension was deposited onto a filter membrane by vacuum-assisted filtration. A certain amount of f-Ti3C2T with a specific solid content was then added. X The mixture was stirred and mixed thoroughly with a 6% PVA-CA solution at a mass ratio of 2:1, and then deposited onto modified cellulose filter paper by vacuum-assisted filtration. The resulting composite material was then hot-pressed at 90°C and 2 MPa; the hot-pressed composite material is the C / M / P composite material.

[0061] Step 5: Preparation of ion-reinforced C / M / P composite materials

[0062] The C / M / P composite material obtained above was immersed in anhydrous calcium chloride (CaCl2) solution at 4 mg / mL for 12 h, washed several times, and then vacuum dried at 60 °C to constant weight to obtain calcium ion-reinforced C / M / P composite material (C / M / P / CaCl2). 2+Using the same method, C / M / P composite materials were placed in aqueous solutions of copper chloride and ferric chloride hexahydrate, respectively, to prepare copper ion-reinforced C / M / P composite materials (C / M / P / Cu). 2+ ) and C / M / P composite materials reinforced with ferric ions (C / M / P / Fe 3+ ).

[0063] In this embodiment, the high-permeability cellulose-based electromagnetic shielding composite film prepared according to the above method can also be used in the electromagnetic shielding protection of wearable electronic devices.

[0064] In this embodiment, cellulose is used as the matrix, and PDAC cationic polymer brushes are grafted onto it to impart antibacterial properties. MXene is used as the conductive filler, and a double-layer structure is designed using vacuum-assisted filtration and hot pressing to achieve excellent electromagnetic shielding performance of the composite material. Catechol-modified polyvinyl alcohol is used to protect MXene, enhancing its effective service life, and metal ions are used to enhance its mechanical strength.

[0065] In this embodiment, cellulose is used as the matrix, and polyacryloxyethyltrimethylammonium chloride is grafted onto it. Modified cellulose and a uniformly mixed few-layer MXene and modified polyvinyl alcohol are deposited sequentially through vacuum-assisted filtration, followed by hot pressing, and finally metal ion strengthening and laser drilling. This material has excellent antibacterial properties, mechanical properties, permeability and electromagnetic shielding, as well as flexibility and long service life.

[0066] This invention utilizes inexpensive raw materials and employs a simple preparation process, thus possessing immense application potential in the field of electromagnetic shielding protection for wearable electronic devices. For instance, when applied to flexible shielding gloves, compared to existing shielding gloves, the electromagnetic shielding effectiveness is increased from 32dB to 36.2dB, the antibacterial property from 95% to 100%, and the breathability (i.e., water vapor transmission rate) from 160g / (m²) 2 The concentration of ·day) increased to 213.2 g / (m 2 The efficiency of this material increased by approximately 33.25% (day), therefore, it has great application potential in fields such as flexible wearable electronic devices, flexible sensor housings, packaging materials for portable electronic devices, and flexible electromagnetic shielding clothing.

[0067] The following describes the process through several examples:

[0068] Example 1

[0069] (1) Under ice bath conditions, 40 mL of dilute hydrochloric acid (approximately 36 wt%) and deionized water were mixed evenly in a polytetrafluoroethylene beaker at a volume ratio of 3:1. 2 g of LiF powder was then added, and the mixture was stirred for a certain period until homogeneous. 2 g of Ti3AlC2 precursor was weighed and slowly added to the prepared system. After addition, the beaker was transferred to a 35°C environment and reacted for 24 h. After the reaction was complete, the reaction solution was washed multiple times with deionized water by centrifugation until neutral. The centrifugation speed was set to 3500 rpm. After multiple washing and shaking, f-Ti3C2T was successfully collected. X (MXene) suspension. After collection, the stable suspension was concentrated at 10,000 rpm for subsequent use.

[0070] (2) 1 g of polyvinyl alcohol (PVA) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) at 80°C. 25 mg of p-toluenesulfonic acid monohydrate (TsOH) and 75 mg of 3,4-dihydroxybenzaldehyde (DBA) were weighed and added to the cooled PVA solution. After addition, the system was protected under nitrogen and reacted at 80°C for 12 h. After the reaction was complete, the precipitate was precipitated in acetone and washed multiple times. The purified precipitate was then vacuum dried in an oven at 45°C for 30 min. After drying, catechol-modified polyvinyl alcohol (PVA-CA) was obtained. This solid was dissolved in deionized water at 90°C, and its concentration was set to 6%.

[0071] (3) Cut the filter paper to a suitable size, then immerse it in 8% 3-(isobutenoyloxy)propyltrimethoxysilane. The solvent system contains 95% ethanol, 1% acetic acid, and 4% deionized water. Silanization is carried out at a constant temperature of 25°C for 1 hour. After treatment, the filter paper is thoroughly washed with deionized water. The silanized cellulose filter paper is then immersed in a mixed aqueous solution containing 30 wt% acryloyloxyethyltrimethylammonium chloride (DAC) and 2 g·L⁻¹ potassium persulfate, and free radical polymerization is carried out at 80°C for 3 hours to obtain cellulose filter paper grafted with PDAC (Cellulose-g-PDAC). Cellulose-g-PDAC is washed multiple times with deionized water and dried at 70°C to constant weight to obtain cellulose grafted with polyacryloyloxyethyltrimethylammonium chloride (Cellulose-g-PDAC).

[0072] (4) Disperse 0.15 g Cellulose-g-PDAC in 50 mL of deionized water. After the reaction is complete, deposit the uniform modified cellulose suspension onto the filter membrane by vacuum-assisted filtration. Add 20 mg of f-Ti3C2T XThe mixture was stirred and mixed thoroughly with a 6% PVA-CA solution at a mass ratio of 2:1, and then deposited onto modified cellulose filter paper by vacuum-assisted filtration. The resulting composite film was then hot-pressed at 90°C and 2 MPa; the hot-pressed composite film is the C / M / P composite material.

[0073] The performance tests of the C / M / P composite material in this embodiment are shown in the final analysis.

[0074] Example 2

[0075] (1) Under ice bath conditions, 40 mL of dilute hydrochloric acid (approximately 36 wt%) and deionized water were mixed evenly in a polytetrafluoroethylene beaker at a volume ratio of 3:1. 2 g of LiF powder was then added, and the mixture was stirred for a certain period until homogeneous. 2 g of Ti3AlC2 precursor was weighed and slowly added to the prepared system. After addition, the beaker was transferred to a 35°C environment and reacted for 24 h. After the reaction was complete, the reaction solution was washed multiple times with deionized water by centrifugation until neutral. The centrifugation speed was set to 3500 rpm. After multiple washing and shaking, f-Ti3C2T was successfully collected. X (MXene) suspension. After collection, the stable suspension was concentrated at 10,000 rpm for subsequent use.

[0076] (2) 1 g of polyvinyl alcohol (PVA) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) at 80°C. 25 mg of p-toluenesulfonic acid monohydrate (TsOH) and 75 mg of 3,4-dihydroxybenzaldehyde (DBA) were weighed and added to the cooled PVA solution. After addition, the system was protected under nitrogen and reacted at 80°C for 12 h. After the reaction was complete, the precipitate was precipitated in acetone and washed multiple times. The purified precipitate was then vacuum dried in an oven at 45°C for 30 min. After drying, catechol-modified polyvinyl alcohol (PVA-CA) was obtained. This solid was dissolved in deionized water at 90°C, and its concentration was set to 6%.

[0077] (3) Cut the filter paper to a suitable size, then immerse it in 8% 3-(isobutenoyloxy)propyltrimethoxysilane. The solvent system contains 95% ethanol, 1% acetic acid, and 4% deionized water. Silanization is carried out at a constant temperature of 25°C for 1 hour. After treatment, the filter paper is thoroughly washed with deionized water. The silanized cellulose filter paper is then immersed in a mixed aqueous solution containing 30 wt% acryloyloxyethyltrimethylammonium chloride (DAC) and 2 g·L⁻¹ potassium persulfate, and free radical polymerization is carried out at 80°C for 3 hours to obtain cellulose filter paper grafted with PDAC (Cellulose-g-PDAC). Cellulose-g-PDAC is washed multiple times with deionized water and dried at 70°C to constant weight to obtain cellulose grafted with polyacryloyloxyethyltrimethylammonium chloride (Cellulose-g-PDAC).

[0078] (4) Disperse 0.15 g Cellulose-g-PDAC in 50 mL of deionized water. After the reaction is complete, deposit the uniform modified cellulose suspension onto the filter membrane by vacuum-assisted filtration. Add 40 mg of f-Ti3C2T X The mixture was stirred and mixed thoroughly with a 6% PVA-CA solution at a mass ratio of 2:1, and then deposited onto modified cellulose filter paper by vacuum-assisted filtration. The resulting composite film was then hot-pressed at 90°C and 2 MPa; the hot-pressed composite film is the C / M / P composite material.

[0079] Example 3

[0080] (1) Under ice bath conditions, 40 mL of dilute hydrochloric acid (approximately 36 wt%) and deionized water were mixed evenly in a polytetrafluoroethylene beaker at a volume ratio of 3:1. 2 g of LiF powder was then added, and the mixture was stirred for a certain period until homogeneous. 2 g of Ti3AlC2 precursor was weighed and slowly added to the prepared system. After addition, the beaker was transferred to a 35°C environment and reacted for 24 h. After the reaction was complete, the reaction solution was washed multiple times with deionized water by centrifugation until neutral. The centrifugation speed was set to 3500 rpm. After multiple washing and shaking, f-Ti3C2T was successfully collected. X (MXene) suspension. After collection, the stable suspension was concentrated at 10,000 rpm for subsequent use.

[0081] (2) 1 g of polyvinyl alcohol (PVA) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) at 80°C. 25 mg of p-toluenesulfonic acid monohydrate (TsOH) and 75 mg of 3,4-dihydroxybenzaldehyde (DBA) were weighed and added to the cooled PVA solution. After addition, the system was protected under nitrogen and reacted at 80°C for 12 h. After the reaction was complete, the precipitate was precipitated in acetone and washed multiple times. The purified precipitate was then vacuum dried in an oven at 45°C for 30 min. After drying, catechol-modified polyvinyl alcohol (PVA-CA) was obtained. This solid was dissolved in deionized water at 90°C, and its concentration was set to 6%.

[0082] (3) Cut the filter paper to a suitable size, then immerse it in 8% 3-(isobutenoyloxy)propyltrimethoxysilane. The solvent system contains 95% ethanol, 1% acetic acid, and 4% deionized water. Silanization is carried out at a constant temperature of 25°C for 1 hour. After treatment, the filter paper is thoroughly washed with deionized water. The silanized cellulose filter paper is then immersed in a mixed aqueous solution containing 30 wt% acryloyloxyethyltrimethylammonium chloride (DAC) and 2 g·L⁻¹ potassium persulfate, and free radical polymerization is carried out at 80°C for 3 hours to obtain cellulose filter paper grafted with PDAC (Cellulose-g-PDAC). Cellulose-g-PDAC is washed multiple times with deionized water and dried at 70°C to constant weight to obtain cellulose grafted with polyacryloyloxyethyltrimethylammonium chloride (Cellulose-g-PDAC).

[0083] (4) Disperse 0.15 g Cellulose-g-PDAC in 50 mL of deionized water. After the reaction is complete, deposit the uniform modified cellulose suspension onto the filter membrane by vacuum-assisted filtration. Add 60 mg of f-Ti3C2T X The mixture was stirred and mixed thoroughly with a 6% PVA-CA solution at a mass ratio of 2:1, and then deposited onto modified cellulose filter paper by vacuum-assisted filtration. The resulting composite film was then hot-pressed at 90°C and 2 MPa; the hot-pressed composite film is the C / M / P composite material.

[0084] Example 4

[0085] (1) Under ice bath conditions, 40 mL of dilute hydrochloric acid (approximately 36 wt%) and deionized water were mixed evenly in a polytetrafluoroethylene beaker at a volume ratio of 3:1. 2 g of LiF powder was then added, and the mixture was stirred for a certain period until homogeneous. 2 g of Ti3AlC2 precursor was weighed and slowly added to the prepared system. After addition, the beaker was transferred to a 35°C environment and reacted for 24 h. After the reaction was complete, the reaction solution was washed multiple times with deionized water by centrifugation until neutral. The centrifugation speed was set to 3500 rpm. After multiple washing and shaking, f-Ti3C2T was successfully collected. X (MXene) suspension. After collection, the stable suspension was concentrated at 10,000 rpm for subsequent use.

[0086] (2) 1 g of polyvinyl alcohol (PVA) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) at 80°C. 25 mg of p-toluenesulfonic acid monohydrate (TsOH) and 75 mg of 3,4-dihydroxybenzaldehyde (DBA) were weighed and added to the cooled PVA solution. After addition, the system was protected under nitrogen and reacted at 80°C for 12 h. After the reaction was complete, the precipitate was precipitated in acetone and washed multiple times. The purified precipitate was then vacuum dried in an oven at 45°C for 30 min. After drying, catechol-modified polyvinyl alcohol (PVA-CA) was obtained. This solid was dissolved in deionized water at 90°C, and its concentration was set to 6%.

[0087] (3) Cut the filter paper to a suitable size, then immerse it in 8% 3-(isobutenoyloxy)propyltrimethoxysilane. The solvent system contains 95% ethanol, 1% acetic acid, and 4% deionized water. Silanization is carried out at a constant temperature of 25°C for 1 hour. After treatment, the filter paper is thoroughly washed with deionized water. The silanized cellulose filter paper is then immersed in a mixed aqueous solution containing 30 wt% acryloyloxyethyltrimethylammonium chloride (DAC) and 2 g·L⁻¹ potassium persulfate, and free radical polymerization is carried out at 80°C for 3 hours to obtain cellulose filter paper grafted with PDAC (Cellulose-g-PDAC). Cellulose-g-PDAC is washed multiple times with deionized water and dried at 70°C to constant weight to obtain cellulose grafted with polyacryloyloxyethyltrimethylammonium chloride (Cellulose-g-PDAC).

[0088] (4) Disperse 0.15 g Cellulose-g-PDAC in 50 mL of deionized water. After the reaction is complete, deposit the uniform modified cellulose suspension onto the filter membrane by vacuum-assisted filtration. Add 80 mg of f-Ti3C2T XThe mixture was stirred and mixed thoroughly with a 6% PVA-CA solution at a mass ratio of 2:1, and then deposited onto modified cellulose filter paper by vacuum-assisted filtration. The resulting composite film was then hot-pressed at 90°C and 2 MPa; the hot-pressed composite film is the C / M / P composite material.

[0089] Example 5

[0090] (1) Under ice bath conditions, 40 mL of dilute hydrochloric acid (approximately 36 wt%) and deionized water were mixed evenly in a polytetrafluoroethylene beaker at a volume ratio of 3:1. 2 g of LiF powder was then added, and the mixture was stirred for a certain period until homogeneous. 2 g of Ti3AlC2 precursor was weighed and slowly added to the prepared system. After addition, the beaker was transferred to a 35°C environment and reacted for 24 h. After the reaction was complete, the reaction solution was washed multiple times with deionized water by centrifugation until neutral. The centrifugation speed was set to 3500 rpm. After multiple washing and shaking, f-Ti3C2T was successfully collected. X (MXene) suspension. After collection, the stable suspension was concentrated at 10,000 rpm for subsequent use.

[0091] (2) 1 g of polyvinyl alcohol (PVA) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) at 80°C. 25 mg of p-toluenesulfonic acid monohydrate (TsOH) and 75 mg of 3,4-dihydroxybenzaldehyde (DBA) were weighed and added to the cooled PVA solution. After addition, the system was protected under nitrogen and reacted at 80°C for 12 h. After the reaction was complete, the precipitate was precipitated in acetone and washed multiple times. The purified precipitate was then vacuum dried in an oven at 45°C for 30 min. After drying, catechol-modified polyvinyl alcohol (PVA-CA) was obtained. This solid was dissolved in deionized water at 90°C, and its concentration was set to 6%.

[0092] (3) Cut the filter paper to a suitable size, then immerse it in 8% 3-(isobutenoyloxy)propyltrimethoxysilane. The solvent system contains 95% ethanol, 1% acetic acid, and 4% deionized water. Silanization is carried out at a constant temperature of 25°C for 1 hour. After treatment, the filter paper is thoroughly washed with deionized water. The silanized cellulose filter paper is then immersed in a mixed aqueous solution containing 30 wt% acryloyloxyethyltrimethylammonium chloride (DAC) and 2 g·L⁻¹ potassium persulfate, and free radical polymerization is carried out at 80°C for 3 hours to obtain cellulose filter paper grafted with PDAC (Cellulose-g-PDAC). Cellulose-g-PDAC is washed multiple times with deionized water and dried at 70°C to constant weight to obtain cellulose grafted with polyacryloyloxyethyltrimethylammonium chloride (Cellulose-g-PDAC).

[0093] (4) Disperse 0.15 g Cellulose-g-PDAC in 50 mL of deionized water. After the reaction is complete, deposit the uniform modified cellulose suspension onto the filter membrane by vacuum-assisted filtration. Add 100 mg of f-Ti3C2T X The mixture was stirred and mixed thoroughly with a 6% PVA-CA solution at a mass ratio of 2:1, and then deposited onto modified cellulose filter paper by vacuum-assisted filtration. The resulting composite film was then hot-pressed at 90°C and 2 MPa; the hot-pressed composite film is the C / M / P composite material.

[0094] The composite films prepared in Examples 1-5 above, which are C / M / P composite materials, were subjected to performance testing, and the following conclusions were obtained:

[0095] See attached document Figure 1a As shown, the composite film obtained by tensile stress-strain testing is a C / M / P composite material. The curve shows that, under the same strain, the composite film prepared by the method of this invention requires a stress that increases with f-Ti3C2T. x It increases with the increase in load.

[0096] like Figure 1b As shown, by comparing the maximum tensile strength of the composite films, it can be seen that with the increase of f-Ti3C2T x With increasing load, the tensile strength of the composite material gradually increased from 7.93 MPa to 23.4 MPa, both indicating a significant improvement in tensile strength and toughness with increasing load. For example, in Example 1, the tensile strength of f-Ti3C2T... xAt a loading of 20 mg, the tensile strength of the composite material is 7.93 MPa, indicating that the C / M / P composite material exhibits certain tensile strength and toughness, making it suitable for wearable electronics applications. In Example 2, in f-Ti3C2T X At a loading of 40 mg, the tensile strength of the composite material is 10.63 MPa, indicating that the C / M / P composite material exhibits certain tensile strength and toughness, making it suitable for wearable electronics applications. In Example 3, in f-Ti3C2T X At a loading of 60 mg, the tensile strength of the composite material was 12.2 MPa, indicating that the C / M / P composite material exhibits good tensile strength and toughness, making it suitable for wearable electronics applications. In Example 4, in f-Ti3C2T X At a loading of 80 mg, the tensile strength of the composite material was 19.24 MPa, indicating that the C / M / P composite material exhibits good tensile strength and toughness, making it suitable for wearable electronics applications. In Example 5, in f-Ti3C2T X When the loading is 100mg, the tensile strength of the composite material is 23.4MPa, which indicates that the C / M / P composite material exhibits excellent tensile strength and toughness, making it suitable for wearable electronics applications.

[0097] like Figure 1c and 1e As shown, in Example 1, in f-Ti3C2T x When the loading is 20 mg, the electrical conductivity of the composite material is 80.4 Sm. -1 SE T 28.6dB, SE A It is 18.9dB, SE R The value is 9.7 dB. In Example 3, when f-Ti3C2T X When the loading is 60 mg, the electrical conductivity of the composite material is 132.2 S m. -1 SE T 35.9dB, SE A 25dB, SE R It is 10.9 dB; in Example 4, when f-Ti3C2T X When the loading is 80 mg, the electrical conductivity of the composite material is 141.7 S m. -1 SE T 36.7dB, SE A It is 25.6dB, SE R The value is 11.1 dB. In Example 5, in f-Ti3C2T X When the loading is 100 mg, the electrical conductivity of the composite material is 145.4 S m.-1 SE T 38.1dB, SE A It is 26.3dB, SE R The value is 11.8 dB, therefore, as shown in the figure, with f-Ti3C2T x With the increase of load, the conductivity of the composite material and the SE of electromagnetic shielding... T SE A and SE R All showed an increasing trend, indicating that the electromagnetic shielding capability of the C / M / P composite material gradually increases with the increase of the load. The mechanical properties, electrical conductivity, and electromagnetic shielding performance of the samples prepared in the embodiments of this invention were tested, such as... Figure 1e As shown, the SE of the composite material T The pressure increased from 28.6 MPa to 38.1 MPa, SE A The SE increased from 18.9 dB to 26.3 dB. R The SE of the C / M / P composite material increased from 9.7 dB to 11.8 dB. T and SE R It exhibits a more uniform growth trend, while SE shows a more consistent growth trend compared to these two. A The increase was not significant. This indicates that all C / M / P composite materials exhibit electromagnetic shielding (ESB) performance far exceeding commercial standards. T >20dB), while when f-Ti3C2T X When the addition amount is 40 mg or more, the C / M / P composite material exhibits excellent electromagnetic shielding performance (SE). T >30dB).

[0098] like Figure 1d As shown, the electromagnetic shielding effectiveness of the composite materials in Examples 1-5 varies at different frequencies. Although the electromagnetic shielding effectiveness fluctuates at different frequencies, all C / M / P composite materials exceed the electromagnetic shielding effectiveness (SE) of commercial standards. T >20dB), which also indicates that the C / M / P composite material has excellent electromagnetic shielding performance.

[0099] See attached document Figure 1fAs shown, in Example 1, the absorption coefficient A is 11% and the reflection coefficient R is 89%, indicating that the C / M / P composite material has good electrical conductivity and a certain degree of electromagnetic shielding performance. In Example 2, the absorption coefficient A is 9% and the reflection coefficient R is 91%, indicating that the C / M / P composite material has certain electrical conductivity and a certain degree of electromagnetic shielding performance. In Example 3, the absorption coefficient A is 8% and the reflection coefficient R is 92%, indicating that the C / M / P composite material has excellent electrical conductivity and electromagnetic shielding performance. In Examples 4-5, the absorption coefficient A is 8% and the reflection coefficient R is 92%, indicating that the C / M / P composite material has excellent electrical conductivity and electromagnetic shielding performance. These parameters demonstrate that the C / M / P composite material possesses good electrical conductivity and electromagnetic shielding performance.

[0100] Example 6

[0101] (1) Under ice bath conditions, 40 mL of dilute hydrochloric acid (approximately 36 wt%) and deionized water were mixed evenly in a polytetrafluoroethylene beaker at a volume ratio of 3:1. 2 g of LiF powder was then added, and the mixture was stirred for a certain period until homogeneous. 2 g of Ti3AlC2 precursor was weighed and slowly added to the prepared system. After addition, the beaker was transferred to a 35°C environment and reacted for 24 h. After the reaction was complete, the reaction solution was washed multiple times with deionized water by centrifugation until neutral. The centrifugation speed was set to 3500 rpm. After multiple washing and shaking, f-Ti3C2T was successfully collected. X (MXene) suspension. After collection, the stable suspension was concentrated at 10,000 rpm for subsequent use.

[0102] (2) 1 g of polyvinyl alcohol (PVA) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) at 80°C. 25 mg of p-toluenesulfonic acid monohydrate (TsOH) and 75 mg of 3,4-dihydroxybenzaldehyde (DBA) were weighed and added to the cooled PVA solution. After addition, the system was protected under nitrogen and reacted at 80°C for 12 h. After the reaction was complete, the precipitate was precipitated in acetone and washed multiple times. The purified precipitate was then vacuum dried in an oven at 45°C for 30 min. After drying, catechol-modified polyvinyl alcohol (PVA-CA) was obtained. This solid was dissolved in deionized water at 90°C, and its concentration was set to 6%.

[0103] (3) Cut the filter paper to a suitable size, then immerse it in 8% 3-(isobutenoyloxy)propyltrimethoxysilane. The solvent system contains 95% ethanol, 1% acetic acid, and 4% deionized water. Silanization is carried out at a constant temperature of 25°C for 1 hour. After treatment, the filter paper is thoroughly washed with deionized water. The silanized cellulose filter paper is then immersed in a mixed aqueous solution containing 30 wt% acryloyloxyethyltrimethylammonium chloride (DAC) and 2 g·L⁻¹ potassium persulfate, and free radical polymerization is carried out at 80°C for 3 hours to obtain cellulose filter paper grafted with PDAC (Cellulose-g-PDAC). Cellulose-g-PDAC is washed multiple times with deionized water and dried at 70°C to constant weight to obtain cellulose grafted with polyacryloyloxyethyltrimethylammonium chloride (Cellulose-g-PDAC).

[0104] (4) Disperse 0.15 g Cellulose-g-PDAC in 50 mL of deionized water. After the reaction is complete, deposit the uniform modified cellulose suspension onto the filter membrane by vacuum-assisted filtration. Add 100 mg of f-Ti3C2T X The mixture was stirred and mixed thoroughly with a 6% PVA-CA solution at a mass ratio of 2:1, and then deposited onto modified cellulose filter paper by vacuum-assisted filtration. The resulting composite film was then hot-pressed at 90°C and 2 MPa; the hot-pressed composite film is the C / M / P composite material.

[0105] (5) The C / M / P composite material obtained above was soaked in anhydrous calcium chloride (CaCl2) solution at 4 mg / mL for 12 h, washed several times, and vacuum dried at 60 °C to constant weight to obtain calcium ion-reinforced C / M / P composite material (C / M / P / CaCl2). 2+ ).

[0106] (6) The calcium ion-reinforced C / M / P composite material (C / M / P / Ca) obtained above 2+ Laser drilling was performed to obtain calcium ion-reinforced C / M / P composite materials with 500 pores and 1000 pores, respectively.

[0107] The mechanical properties of the samples prepared in the embodiments of the present invention were tested, such as... Figure 3c As can be seen, in this embodiment, the tensile strength of the composite material increased by 23.42% after bonding with calcium ions, reaching 28.88 MPa.

[0108] Through append Figure 2a As can be seen, in this embodiment, the prepared C / M / P / Ca 2+The composite material's cross-sectional Ti element distribution diagram shows that a1 and f1 represent the cross-sectional morphology of different regions of the composite material, demonstrating its porous and fibrous structure; a2 shows the surface nitrogen distribution, indicating the presence of nitrogen in the composite material; b and c represent the addition of 20 mg and 100 mg of f-Ti3C2T, respectively. X The fibrous structure of the composite material indicates that the 100mg fiber structure is more compact; d represents the layered structure of the composite material, and e represents a detailed cross-sectional layered view, both clearly showing the layered structure of MXene and the cellulose matrix; f2 represents the distribution of carbon, indicating the presence of carbon in the composite material, which is a major component of cellulose, polymers, and other components; f3 represents the distribution of titanium, a characteristic element of MXene, indicating that MXene is uniformly distributed in the composite material.

[0109] Through append Figure 2b As can be seen, C / M / P / Ca in this embodiment 2+ The distribution diagram of Ca element in the cross section of the composite material shows that Ca element is uniformly and densely distributed in the composite material without agglomeration or localized agglomeration, which indicates the uniformity and consistency of the material composition.

[0110] The conductivity and electromagnetic shielding performance of the samples prepared in the embodiments of the present invention were tested, such as... Figure 2c and 2d As shown, after soaking in CaCl2 solution for 12 hours, its shielding effectiveness decreased by only 0.9 dB, still maintaining a high level of 37.2 dB, which is 97.67% of the original shielding effectiveness. Figure 2e and 2f As shown, after 1000 bends, C / M / P / Ca 2+ -5 still maintains a shielding effectiveness of 35.5dB, a decrease of only 1.7dB compared to the original level, which is 95.43% of the original shielding value. Figure 2h and 2i As shown, C / M / P / Ca 2+ The electromagnetic shielding effectiveness of the composite material showed no significant decrease in the initial state, and after 10, 20, 30, and 60 days. For example... Figure 2m and 2n As shown, with 500 pores, the shielding effectiveness is 36.8 dB; with 1000 pores, the shielding effectiveness is 36.2 dB. The composite material maintains excellent penetration shielding and electromagnetic shielding performance. Figure 2j As shown, the C / M / P / Ca2+ composite material exhibits very low electromagnetic wave absorption coefficient (A) proportions (below 10%) in the initial state and at 10, 20, 30, and 60 days, while its electromagnetic wave reflection coefficient (R) proportions are very high (above 90%). Therefore, it can be concluded that the C / M / P / Ca2+ composite material...2+ -5 composite materials exhibit excellent electrical conductivity and electromagnetic shielding properties under different conditions.

[0111] like Figure 2g As shown, the XRD patterns of the composite material in its initial state and after 10, 20, 30, 40, 50, and 60 days show no significant changes in the position and intensity of the diffraction peaks. This indicates that the structure has not changed significantly, demonstrating the long-term structural stability of the material.

[0112] The antibacterial properties of the samples prepared in the embodiments of the present invention were tested, with reference to the appendix. Figure 2k-2l As shown, the antibacterial effect of the composite material was used as a control group, and the C / M / P / Ca ratio was calculated. 2+ The inhibition rate of -5 against Escherichia coli increased from 98.67% to 100%, while the inhibition rate against Staphylococcus aureus remained at 100%. This indicates that the overall antibacterial performance is excellent, stable, and the inhibitory effect is almost complete.

[0113] The water vapor transmission rate of the samples prepared in the embodiments of the present invention was tested, such as... Figure 2o As shown, when the number of pores is 0, C / M / P / Ca 2+ The water vapor transmission rate is 162.7 g / m. 2 • day, C / M / P / Ca when the number of pores is 500 2+ The water vapor transmission rate is 201.5 g / m. 2 • day, C / M / P / Ca when the number of pores is 1000 2+ The water vapor transmission rate is 213.2 g / m. 2 ·day.

[0114] Example 7

[0115] (1) Under ice bath conditions, 40 mL of dilute hydrochloric acid (approximately 36 wt%) and deionized water were mixed evenly in a polytetrafluoroethylene beaker at a volume ratio of 3:1. 2 g of LiF powder was then added, and the mixture was stirred for a certain period until homogeneous. 2 g of Ti3AlC2 precursor was weighed and slowly added to the prepared system. After addition, the beaker was transferred to a 35°C environment and reacted for 24 h. After the reaction was complete, the reaction solution was washed multiple times with deionized water by centrifugation until neutral. The centrifugation speed was set to 3500 rpm. After multiple washing and shaking, f-Ti3C2T was successfully collected. X (MXene) suspension. After collection, the stable suspension was concentrated at 10,000 rpm for subsequent use.

[0116] (2) 1 g of polyvinyl alcohol (PVA) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) at 80°C. 25 mg of p-toluenesulfonic acid monohydrate (TsOH) and 75 mg of 3,4-dihydroxybenzaldehyde (DBA) were weighed and added to the cooled PVA solution. After addition, the system was protected under nitrogen and reacted at 80°C for 12 h. After the reaction was complete, the precipitate was precipitated in acetone and washed multiple times. The purified precipitate was then vacuum dried in an oven at 45°C for 30 min. After drying, catechol-modified polyvinyl alcohol (PVA-CA) was obtained. This solid was dissolved in deionized water at 90°C, and its concentration was set to 6%.

[0117] (3) Cut the filter paper to a suitable size, then immerse it in 8% 3-(isobutenoyloxy)propyltrimethoxysilane. The solvent system contains 95% ethanol, 1% acetic acid, and 4% deionized water. Silanization is carried out at a constant temperature of 25°C for 1 hour. After treatment, the filter paper is thoroughly washed with deionized water. The silanized cellulose filter paper is then immersed in a mixed aqueous solution containing 30 wt% acryloyloxyethyltrimethylammonium chloride (DAC) and 2 g·L⁻¹ potassium persulfate, and free radical polymerization is carried out at 80°C for 3 hours to obtain cellulose filter paper grafted with PDAC (Cellulose-g-PDAC). Cellulose-g-PDAC is washed multiple times with deionized water and dried at 70°C to constant weight to obtain cellulose grafted with polyacryloyloxyethyltrimethylammonium chloride (Cellulose-g-PDAC).

[0118] (4) Disperse 0.15 g Cellulose-g-PDAC in 50 mL of deionized water. After the reaction is complete, deposit the uniform modified cellulose suspension onto the filter membrane by vacuum-assisted filtration. Add 100 mg of f-Ti3C2T X The mixture was stirred and mixed thoroughly with a 6% PVA-CA solution at a mass ratio of 2:1, and then deposited onto modified cellulose filter paper by vacuum-assisted filtration. The resulting composite material was then hot-pressed at 90°C and 2 MPa; the hot-pressed composite material is the C / M / P composite material.

[0119] (5) The C / M / P composite material obtained above was soaked in a 4 mg / mL copper chloride (CuCl2) solution for 12 h, washed several times, and vacuum dried at 60 °C to constant weight to obtain a copper ion-reinforced C / M / P composite material (C / M / P / CuCl2). 2+ ).

[0120] The mechanical and electrical properties of the samples prepared in the embodiments of the present invention were tested, such as... Figure 3cAs shown, after the composite material was bonded with copper ions, the tensile strength increased by 31.07%, reaching 30.67 MPa, indicating a significant improvement in mechanical properties after bonding. Figure 3d As shown, after the composite material is bonded with copper ions, the conductivity is 140.3 S / m, which does not show a significant decrease compared with the blank sample, indicating that it can still maintain good electrical conductivity after ion bonding.

[0121] Example 8

[0122] (1) Under ice bath conditions, 40 mL of dilute hydrochloric acid (approximately 36 wt%) and deionized water were mixed evenly in a polytetrafluoroethylene beaker at a volume ratio of 3:1. 2 g of LiF powder was then added, and the mixture was stirred for a certain period until homogeneous. 2 g of Ti3AlC2 precursor was weighed and slowly added to the prepared system. After addition, the beaker was transferred to a 35°C environment and reacted for 24 h. After the reaction was complete, the reaction solution was washed multiple times with deionized water by centrifugation until neutral. The centrifugation speed was set to 3500 rpm. After multiple washing and shaking, f-Ti3C2T was successfully collected. X (MXene) suspension. After collection, the stable suspension was concentrated at 10,000 rpm for subsequent use.

[0123] (2) 1 g of polyvinyl alcohol (PVA) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) at 80°C. 25 mg of p-toluenesulfonic acid monohydrate (TsOH) and 75 mg of 3,4-dihydroxybenzaldehyde (DBA) were weighed and added to the cooled PVA solution. After addition, the system was protected under nitrogen and reacted at 80°C for 12 h. After the reaction was complete, the precipitate was precipitated in acetone and washed multiple times. The purified precipitate was then vacuum dried in an oven at 45°C for 30 min. After drying, catechol-modified polyvinyl alcohol (PVA-CA) was obtained. This solid was dissolved in deionized water at 90°C, and its concentration was set to 6%.

[0124] (3) Cut the filter paper to a suitable size, then immerse it in 8% 3-(isobutenoyloxy)propyltrimethoxysilane. The solvent system contains 95% ethanol, 1% acetic acid, and 4% deionized water. Silanization is carried out at a constant temperature of 25°C for 1 hour. After treatment, the filter paper is thoroughly washed with deionized water. The silanized cellulose filter paper is then immersed in a mixed aqueous solution containing 30 wt% acryloyloxyethyltrimethylammonium chloride (DAC) and 2 g·L⁻¹ potassium persulfate, and free radical polymerization is carried out at 80°C for 3 hours to obtain cellulose filter paper grafted with PDAC (Cellulose-g-PDAC). Cellulose-g-PDAC is washed multiple times with deionized water and dried at 70°C to constant weight to obtain cellulose grafted with polyacryloyloxyethyltrimethylammonium chloride (Cellulose-g-PDAC).

[0125] (4) Disperse 0.15 g Cellulose-g-PDAC in 50 mL of deionized water. After the reaction is complete, deposit the uniform modified cellulose suspension onto the filter membrane by vacuum-assisted filtration. Add 100 mg of f-Ti3C2T X The mixture was stirred and mixed thoroughly with a 6% PVA-CA solution at a mass ratio of 2:1, and then deposited onto modified cellulose filter paper by vacuum-assisted filtration. The resulting composite material was then hot-pressed at 90°C and 2 MPa; the hot-pressed composite material is the C / M / P composite material.

[0126] (5) The C / M / P composite material obtained above was soaked in a 4 mg / mL ferric chloride hexahydrate (FeCl3) solution for 12 h, washed several times, and vacuum dried at 60 °C to constant weight to obtain a ferric ion-reinforced C / M / P composite material (C / M / P / FeCl3). 3+ ).

[0127] See attached document Figure 3a As shown, the microscopic interaction model of the composite material bonded to metal ions can be seen, involving components such as f-Ti3C2T. X The presence of PVA-CA and metal ions indicates that the materials are bonded together through hydrogen bonds, catechol-Ti coordination bonds, and metal ion-O-Ti coordination bonds.

[0128] The mechanical and electrical properties of the samples prepared in the embodiments of the present invention were tested, such as... Figure 3b As shown, the tensile stress-strain test results show that, compared with the C / M / P composite material, the composite material bonded to metal ions prepared in Examples 6-8 requires a higher tensile stress under the same strain, indicating that the composite material bonded to metal ions has better mechanical strength. Figure 3cAs shown, after the composite material is bonded with ferric ions, the tensile strength increases by 40.43%, reaching 32.86 MPa, indicating a significant improvement in mechanical properties after bonding. Figure 3d As shown in Figures 3c and 3d, the electrical conductivity of the composite material after bonding with ferric ions is 140.9 S / m, which does not show a significant decrease compared to the blank sample, indicating that it can still maintain good electrical conductivity after ion bonding. Furthermore, as shown in Figures 3c and 3d, the tensile strength and electrical conductivity of the composite material are significantly improved after bonding with metal ions, and the electrical conductivity remains at a high level. Therefore, the composite material still possesses excellent mechanical and electrical properties after bonding with metal ions.

[0129] As can be seen from the above embodiments and related experimental tests, the preparation method of the present invention produces a high-permeability cellulose-based electromagnetic shielding composite film with good mechanical properties, electrical conductivity, electromagnetic shielding properties and antibacterial properties.

[0130] The high-permeability cellulose-based electromagnetic shielding composite film prepared in this embodiment can be applied to the electromagnetic protection field of flexible wearable electronic devices and promote the high-value application of cellulose materials, broadening the application range of cellulose-based and MXene. Specifically, it is applied with high-permeability cellulose-based, MXene and modified polyvinyl alcohol as core materials. It has both good mechanical properties and electromagnetic shielding performance, as well as low cost and simple process, and can adapt to the flexible and thin requirements of wearable devices.

[0131] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

[0132] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0133] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a high-permeability cellulose-based electromagnetic shielding composite film, characterized in that, Includes the following steps, S1) The MXene suspension was sequentially etched and concentrated to obtain a few-layer MXene; S2) Polyvinyl alcohol is modified with catechol by acetalization. S3) Cellulose free radical polymerization yields grafted polyacryloxyethyltrimethylammonium chloride cellulose; S4) Grafted polyacryloxyethyltrimethylammonium chloride cellulose is dispersed and deposited on the filter membrane to form modified cellulose filter paper. Catechol-modified polyvinyl alcohol is mixed with few-layer MXene and deposited on the modified cellulose filter paper. The composite film is obtained by hot pressing deposition. The mass ratio of cellulose:MXene:modified polyvinyl alcohol is from 50:2:1 to 10:2:1; S5) The composite film is soaked in a metal salt solution, dried, and then laser-drilled to obtain an electromagnetic shielding composite film containing high-permeability cellulose-based material.

2. The method for preparing the high-permeability cellulose-based electromagnetic shielding composite film according to claim 1, characterized in that, The MXene suspension was prepared using a LiF-HCl system, wherein the LiF-HCl system is at least Ti3C2T. X Solution, Ti3N2T X Solution, Ti3CNT X Solution or Ti2CT X One of the components in a solution.

3. The method for preparing the high-permeability cellulose-based electromagnetic shielding composite film according to claim 1, characterized in that, The cellulose free radical polymerization in step S3) includes cellulose silanization modification and free radical combination of silanized cellulose with polyacryloxyethyltrimethylammonium chloride.

4. The method for preparing the high-permeability cellulose-based electromagnetic shielding composite film according to claim 3, characterized in that, The cellulose alkylation modification specifically involves impregnating a cellulose matrix with a compound containing hydrolyzable silane groups and vinyl groups.

5. The method for preparing the high-permeability cellulose-based electromagnetic shielding composite film according to claim 3, characterized in that, The specific combination consists of alkylated cellulose impregnated with a quaternary ammonium salt monomer containing polymerizable double bonds at a mass fraction of 20%-40% and 2 g·L⁻¹. - The grafted polyquaternary ammonium cellulose was obtained by reacting the initiator in a mixed aqueous solution at 70-100℃ for 2-5 hours, followed by washing with deionized water multiple times and drying at 50-80℃.

6. The method for preparing the high-permeability cellulose-based electromagnetic shielding composite film according to claim 1, characterized in that, In step S3), the suspension of few-layer MXene and the modified polyvinyl alcohol aqueous solution with a mass fraction of 6% are mixed at a mass ratio of 2:1 and stirred evenly.

7. The method for preparing a high-permeability cellulose-based electromagnetic shielding composite film according to claim 1, characterized in that, In step S4), the hot pressing temperature is 70-100℃ and the pressure is 1-5 MPa.

8. The method for preparing a high-permeability cellulose-based electromagnetic shielding composite film according to claim 1, characterized in that, In step S5), the metal salt solution is at least one of copper chloride solution, ferric chloride hexahydrate solution, or calcium chloride solution.

9. The method for preparing a high-permeability cellulose-based electromagnetic shielding composite film according to claim 1, characterized in that, In step S5), the diameter of the laser-drilled hole is a fixed 15μm.

10. The method for preparing a high-permeability cellulose-based electromagnetic shielding composite film according to any one of claims 1-9, and the application of the prepared high-permeability cellulose-based electromagnetic shielding composite film in electromagnetic shielding protection of wearable electronic devices.

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