A MXene / CNT and oxidized sodium alginate modified collagen composite aerogel and its preparation method and application

Abstract

The present invention discloses a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel, and a preparation method and application thereof. The preparation method uses collagen as a matrix and MXene and carbon nanotubes as conductive fillers. The MXene / CNT and oxidized sodium alginate modified collagen composite aerogel with electromagnetic shielding performance is prepared by freeze-drying technology. The three-dimensionally connected sheets inside the modified collagen composite aerogel serve as shielding walls, showing the advantage of enhancing the interaction between electromagnetic waves and aerogels, improving multiple reflections and scattering, and becoming one of the main ways to attenuate incident electromagnetic waves. Through the synergistic effect of MXene and CNT, a good conductive network is formed, and most electromagnetic waves are guided into the modified collagen composite aerogel, thereby obtaining efficient EMI shielding performance. In addition, the electromagnetic shielding of the aerogel is mainly based on electromagnetic wave absorption.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials and relates to composite aerogels, and in particular to a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel, and a preparation method and application thereof. Background Art

[0002] In recent years, the widespread use of electronic devices has brought great convenience to people, but it has also brought a series of electromagnetic interference (EMI) problems, which will have a serious impact on the operation of electronic devices and may endanger human health. Electromagnetic shielding is the most convenient and effective way to eliminate electromagnetic interference. EMI shielding uses the inherent properties of conductive or magnetic electromagnetic shielding materials to block the propagation path of electromagnetic interference sources and reflect or confine electromagnetic waves within the electromagnetic shielding materials, eliminating the electromagnetic interference problem at the root. In order to meet the EMI shielding requirements of electronic devices for light weight, high absorption loss, and good processing performance, aerogels are attracting more and more attention from researchers due to their unique structure that can effectively absorb and dissipate electromagnetic waves.

[0003] Traditional electromagnetic shielding materials are often made of metal, but their application in electromagnetic shielding is limited by high cost, difficult processing, corrosion, high density, and susceptibility to secondary reflection contamination from the metal itself. Studies have shown that replacing metal with nanomaterials as fillers or reinforcements to form aerogels with three-dimensional porous networks can improve the physical and chemical properties of composite aerogels (such as conductivity, density, porosity, and mechanical strength), and enhance their EMI shielding performance. Currently, one-dimensional carbon nanotubes and two-dimensional MXenes are widely used in EMI shielding due to their advantages such as light weight, large specific surface area, and inherent conductivity. Furthermore, the use of mixed conductive fillers of different geometries, particularly one-dimensional and two-dimensional nanofillers, can improve their dispersibility. With global resource shortages, the use of renewable biomass resources in the preparation of EMI shielding materials is becoming a future trend. Modifying renewable collagen, which has a unique triple helix structure, and combining it with one-dimensional and two-dimensional nanofillers has the potential to produce EMI shielding materials with high electromagnetic wave attenuation capabilities. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a MXene / CNT and sodium alginate oxidized modified collagen composite aerogel and its preparation method and application. The collagen aerogel is modified by carbon nanomaterials to optimize the internal structure to form a continuous conductive network, and a composite aerogel with excellent conductive properties is prepared, which is applied to the field of electromagnetic interference shielding to achieve efficient electromagnetic shielding performance.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel comprises the following steps:

[0007] Step 1: Prepare a single layer or a few layers of MXene material;

[0008] Step 2: Take 350-750 parts of deionized water or phosphate buffer by mass, add 50-160 parts of collagen, 5-18 parts of oxidized sodium alginate, 50-140 parts of MXene prepared in step 1 and 60-300 parts of CNT to form a mixed solution, react the mixed solution at a temperature of -5-15°C for 0.2-3h, then inject the reacted mixed solution into a mold and freeze it, and then freeze-dry it to obtain a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel.

[0009] The present invention also has the following technical features:

[0010] Preferably, the method for preparing the single-layer or few-layer MXene material in step 1 comprises:

[0011] According to the mass ratio, 25 to 85 parts of LiF are added to 30 to 110 parts of 9M HCl solution, mixed evenly, and then 50 to 105 parts of MAX powder are added for chemical etching for 12 to 60 hours. After the reaction is completed, the solution is centrifuged and ultrasonically dispersed to obtain a single-layer or few-layer MXene solution, which is then freeze-dried to obtain a single-layer or few-layer MXene material.

[0012] Furthermore, the MAX powder includes one or more of Ti3AlC2, Ti3AlCN, Ti3AlC, and Ti3AlN, and the MXene material obtained after chemical etching includes Ti3C2T x 、Ti3CNT x 、Ti2CT x A mixture of one or more of.

[0013] Furthermore, the centrifugal washing agent is a centrifugal washing method using deionized water for repeated 10 to 40 times, and the centrifuge speed is 200 to 5000 r / min.

[0014] Furthermore, the ultrasonic dispersion is performed by dispersing the precipitate by ultrasonication for 0.5 to 3 hours at a power of 200 to 1000 W.

[0015] Preferably, the oxidized sodium alginate in step 2 has an aldehyde content of 2 to 10 mmol / g and an oxidation degree of 20 to 80%.

[0016] Preferably, the CNTs in step 2 include a mixture of one or more of multi-walled carbon nanotubes, single-walled carbon nanotubes, carboxylated carbon nanotubes, and amino-treated carbon nanotubes.

[0017] The present invention also protects a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel prepared by the method as described above and its application in the field of electromagnetic interference shielding.

[0018] Compared with the prior art, the present invention has the following technical effects:

[0019] The present invention uses oxidized sodium alginate modified collagen as the main body, MXene and carbon nanotubes as conductive fillers, and through the synergistic effect of MXene and CNT, CNT acts as a conductive "bridge" to connect MXene nanosheets, constructing a conductive path through point-to-surface contact, interacting with the oxidized sodium alginate modified collagen, and internally connecting into a three-dimensional sheet structure, forming a continuous conductive network. This shows the advantage of enhancing the interaction between electromagnetic waves and aerogel, forming a shielding wall, improving multiple reflections and scattering, and becoming one of the main ways to attenuate incident electromagnetic waves.

[0020] Collagen is one of the most abundant renewable biomass resources in the world. It has a unique triple helix structure and is rich in electronic dipoles and molecular bound charges. It is a bioelectret that can be polarized in an electromagnetic field and has a certain ability to lose electromagnetic waves. By oxidizing collagen modified with sodium alginate, a large number of micro-conductive units are formed in the collagen composite aerogel, and the density of the collagen composite aerogel is increased, and the pore structure of the aerogel is improved, so that the aerogel has high conductivity and guides most electromagnetic waves (EMWs) into the interior of the aerogel, thereby obtaining efficient EMI shielding performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a TEM image of MXene prepared in Example 3;

[0022] Figure 2 This is the appearance of the MXene dispersion prepared in Example 3;

[0023] Figure 3 is a SEM image of the modified collagen composite aerogel prepared in Example 3 at a resolution of 200 μm;

[0024] Figure 4 is a graph showing the electromagnetic shielding performance of the modified collagen composite aerogel prepared in Example 3;

[0025] Figure 5 is the reflection loss (SE) of the modified collagen composite aerogel R ), absorption loss (SE A ) and total electromagnetic shielding effectiveness (SET ). DETAILED DESCRIPTION

[0026] The specific contents of the present invention are further explained in detail below with reference to the embodiments.

[0027] In the following embodiments, MAX powder includes one or more of Ti3AlC2, Ti3AlCN, Ti3AlC, and Ti3AlN, and the MXene material obtained after chemical etching includes Ti3C2T x 、Ti3CNT x 、Ti2CT x A mixture of one or more of any proportion;

[0028] The pH of phosphate buffer is 7;

[0029] The aldehyde content of the oxidized sodium alginate is 2 to 10 mmol / g, and the degree of oxidation is 20 to 80%;

[0030] The CNT includes a mixture of one or more of multi-walled carbon nanotubes, single-walled carbon nanotubes, carboxylated carbon nanotubes, and amino-treated carbon nanotubes in any proportion.

[0031] Example 1

[0032] This embodiment provides a method for preparing a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel, comprising the following steps:

[0033] Step 1: Add 25 parts of LiF to 30 parts of 9M HCl solution, mix well, then add 50 parts of MAX powder and chemically etch for 12 hours. After the reaction is completed, use deionized water to repeatedly centrifuge and wash 10 times at 5000 r / min. Disperse the precipitate by ultrasonication at 200 W power for 0.5 hours to obtain a single-layer or few-layer MXene solution, which is then freeze-dried to obtain a single-layer or few-layer MXene material.

[0034] Step 2: Take 350 parts of deionized water or phosphate buffer, add 50 parts of collagen, 5 parts of oxidized sodium alginate, 50 parts of MXene, and 60 parts of CNT to form a mixed solution, react the mixed solution at -5°C for 0.2h, then inject the reacted mixed solution into a mold and freeze it, and then freeze-dry it to obtain MXene / CNT and oxidized sodium alginate modified collagen composite aerogel.

[0035] Example 2

[0036] This embodiment provides a method for preparing a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel, comprising the following steps:

[0037] Step 1: Add 50 parts of LiF to 65 parts of 4M HCl solution, mix well, then add 70 parts of MAX powder and chemically etch for 24 hours. After the reaction is completed, use deionized water to repeatedly centrifuge and wash 15 times at 3000 r / min. Disperse the precipitate by ultrasonication at 500 W power for 1 hour to obtain a single-layer or few-layer MXene solution, which is then freeze-dried to obtain a single-layer or few-layer MXene material.

[0038] Step 2: Take 400 parts of deionized water or phosphate buffer, add 70 parts of collagen, 6 parts of oxidized sodium alginate, 70 parts of MXene, and 110 parts of CNT to form a mixed solution, react the mixed solution at 0°C for 0.5h, then inject the reacted mixed solution into a mold and freeze it, and then freeze-dry it to obtain MXene / CNT and oxidized sodium alginate modified collagen composite aerogel.

[0039] Example 3

[0040] This embodiment provides a method for preparing a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel, comprising the following steps:

[0041] Step 1: Add 60 parts of LiF to 80 parts of 3M HCl solution, mix well, then add 90 parts of MAX powder and chemically etch for 36 hours. After the reaction is completed, use deionized water to repeatedly centrifuge and wash 20 times at a speed of 2000r / min. Disperse the precipitate by ultrasonication at a power of 600W for 1.5 hours to obtain a single-layer or few-layer MXene solution, which is then freeze-dried to obtain a single-layer or few-layer MXene material.

[0042] Step 2: Take 600 parts of deionized water or phosphate buffer, add 120 parts of collagen, 10 parts of oxidized sodium alginate, 125 parts of MXene, and 190 parts of CNT to form a mixed solution, react the mixed solution at 5°C for 1 hour, then inject the reacted mixed solution into a mold and freeze it, and then freeze-dry it to obtain MXene / CNT and oxidized sodium alginate modified collagen composite aerogel.

[0043] The samples obtained in Example 3 were characterized and tested as follows:

[0044] Figure 1 is a TEM image of MXene prepared in Example 3; Figure 1 It can be seen that single-layer or few-layer two-dimensional MXene nanosheets were successfully prepared by chemical etching.

[0045] Figure 2 This is the appearance of the MXene dispersion prepared in Example 3; Figure 2The demonstrated MXene dispersion exhibits a Tyndall effect, indicating that MXene has colloidal characteristics.

[0046] Figure 3 is a SEM image of the modified collagen composite aerogel prepared in Example 3 at a resolution of 200 μm; Figure 3 It can be seen that the modified collagen composite aerogel presents a regular and dense pore structure. Under the synergistic effect of MXene and CNT, the pore wall structure of the MCAC composite aerogel is more solid, and a more complete conductive network is obtained, thereby obtaining efficient EMI shielding performance.

[0047] Figure 4 is the electromagnetic shielding performance diagram of the modified collagen composite aerogel prepared in Example 3; Figure 4 It can be seen that the total electromagnetic shielding effectiveness can reach 96.76dB.

[0048] Figure 5 is the reflection loss (SE) of the modified collagen composite aerogel R ), absorption loss (SE A ) and total electromagnetic shielding effectiveness (SE T );Depend on Figure 5 It can be seen that the absorption loss shows an overwhelming advantage compared with the reflection loss, which indicates that the electromagnetic shielding of the modified collagen composite aerogel is mainly based on electromagnetic wave absorption.

[0049] Example 4

[0050] This embodiment provides a method for preparing a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel, comprising the following steps:

[0051] Step 1: Add 70 parts of LiF to 85 parts of 3M HCl solution, mix well, then add 95 parts of MAX powder and chemically etch for 48 hours. After the reaction is completed, use deionized water to repeatedly centrifuge and wash 30 times at a speed of 1000 r / min. Disperse the precipitate by ultrasonication at 800 W power for 2 hours to obtain a single-layer or few-layer MXene solution, which is then freeze-dried to obtain a single-layer or few-layer MXene material;

[0052] Step 2: Take 700 parts of deionized water or phosphate buffer, add 150 parts of collagen, 15 parts of oxidized sodium alginate, 135 parts of MXene, and 210 parts of CNT to form a mixed solution, react the mixed solution at 10°C for 2 hours, then inject the reacted mixed solution into a mold and freeze it, and then freeze-dry it to obtain MXene / CNT and oxidized sodium alginate modified collagen composite aerogel.

[0053] Example 5

[0054] This embodiment provides a method for preparing a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel, comprising the following steps:

[0055] Step 1: Add 85 parts of LiF to 110 parts of 3M HCl solution, mix well, add 105 parts of MAX powder and chemically etch for 60 hours. After the reaction is completed, use deionized water to repeatedly centrifuge and wash 40 times at a speed of 200 r / min. Disperse the precipitate by ultrasonication at a power of 1000 W for 3 hours to obtain a single-layer or few-layer MXene solution, and then freeze-dry to obtain a single-layer or few-layer MXene material;

[0056] Step 2: Take 750 parts of deionized water or phosphate buffer, add 160 parts of collagen, 18 parts of oxidized sodium alginate, 140 parts of MXene, and 300 parts of CNT to form a mixed solution, react the mixed solution at 15°C for 3 hours, then inject the reacted mixed solution into a mold and freeze it, and then freeze-dry it to obtain MXene / CNT and oxidized sodium alginate modified collagen composite aerogel.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for preparing a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel, characterized in that: The following steps are involved: Step 1: Prepare a single layer or a few layers of MXene material; Step 2: Take 350-750 parts of deionized water or phosphate buffer by mass, add 50-160 parts of collagen, 5-18 parts of oxidized sodium alginate, 50-140 parts of MXene prepared in step 1 and 60-300 parts of CNT to form a mixed solution, react the mixed solution at a temperature of -5-15°C for 0.2-3h, then inject the reacted mixed solution into a mold and freeze it, and then freeze-dry it to obtain a MXene / CNT and oxidized sodium alginate modified collagen composite aerogel.

2. The method for preparing the MXene / CNT and oxidized sodium alginate modified collagen composite aerogel according to claim 1, wherein: The method for preparing the single-layer or few-layer MXene material described in step 1 includes: According to the mass ratio, 25 to 85 parts of LiF are added to 30 to 110 parts of 9M HCl solution, mixed evenly, and then 50 to 105 parts of MAX powder are added for chemical etching for 12 to 60 hours. After the reaction is completed, the solution is centrifuged and ultrasonically dispersed to obtain a single-layer or few-layer MXene solution, which is then freeze-dried to obtain a single-layer or few-layer MXene material.

3. The method for preparing the MXene / CNT and oxidized sodium alginate modified collagen composite aerogel according to claim 2, wherein: The MAX powder includes one or more of Ti3AlC2, Ti3AlCN, Ti3AlC, and Ti3AlN. The MXene material obtained after chemical etching includes Ti3C2T x 、Ti3CNT x 、Ti2CT x A mixture of one or more of.

4. The method for preparing the MXene / CNT and oxidized sodium alginate modified collagen composite aerogel according to claim 2, wherein: The centrifugal washing agent is prepared by repeatedly centrifuging and washing with deionized water for 10 to 40 times, with the centrifuge speed being 200 to 5000 r / min.

5. The method for preparing the MXene / CNT and oxidized sodium alginate modified collagen composite aerogel according to claim 2, wherein: The ultrasonic dispersion is performed by ultrasonically dispersing the precipitate for 0.5 to 3 hours at a power of 200 to 1000 W.

6. The method for preparing the MXene / CNT and oxidized sodium alginate modified collagen composite aerogel according to claim 1, wherein: The oxidized sodium alginate in step 2 has an aldehyde content of 2 to 10 mmol / g and an oxidation degree of 20 to 80%.

7. The method for preparing the MXene / CNT and oxidized sodium alginate modified collagen composite aerogel according to claim 1, wherein: The CNTs in step 2 include a mixture of one or more of multi-walled carbon nanotubes, single-walled carbon nanotubes, carboxylated carbon nanotubes, and amino-treated carbon nanotubes.

8. A MXene / CNT and oxidized sodium alginate modified collagen composite aerogel prepared by the method according to any one of claims 1 to 7.

9. Use of the MXene / CNT and oxidized sodium alginate modified collagen composite aerogel according to claim 8 in the field of electromagnetic interference shielding.

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