A MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel and its preparation method

Abstract

The present invention discloses a MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel and a preparation method thereof, comprising the following steps: 1. mixing an aqueous solution of sodium carboxymethyl cellulose and an aqueous solution of sodium periodate, fully reacting at 20-60° C., adding anhydrous ethanol, and filtering, washing, and freeze-drying in sequence after precipitation to obtain dialdehyde carboxymethyl cellulose; 2. dispersing 0.3 g of collagen in 35-50 mL of acetic acid solution with a concentration of 0.5 mol / mL to obtain a collagen solution; 3. taking dialdehyde carboxymethyl cellulose and stirring at room temperature; 4. stirring at room temperature; 5. stirring at room temperature; 6. stirring at room temperature; 7. stirring at room temperature; 8. stirring at room temperature; 9. stirring at room temperature; 10. 1. The MXene and collagen solution are evenly mixed to obtain a mixed solution C, which is cross-linked in an ice-water bath to obtain a dialdehyde carboxymethyl cellulose modified collagen solution; 2. MXene and dopamine hydrochloride monomers are sequentially added to the MXene aqueous solution, and the mixture is freeze-dried after the reaction to obtain MXene@PDA powder; 3. MXene@PDA powder is added to the dialdehyde carboxymethyl cellulose modified collagen solution, and the mixture is freeze-dried after the reaction to obtain MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel with good photothermal conversion performance.

Description

Technical Field

[0001] The present invention relates to a thermal insulation material, in particular to a MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel and a preparation method thereof. Background Art

[0002] With the acceleration of industrialization and urbanization, energy consumption has become a critical issue. High-efficiency thermal management materials are widely recognized as a more effective means of energy conservation and have been widely used in the construction, transportation, outdoor tents, and outdoor electronic devices. However, existing thermal insulation materials have the disadvantages of environmental pollution and poor thermal insulation performance. Mineral wool, fiberglass, and clay are the most commonly used inorganic insulation materials, but their mechanical and thermal insulation properties are not outstanding. Furthermore, while organic thermal insulation materials such as foam, sponge, and epoxy resin offer good thermal insulation properties, their primary raw materials are derived from non-renewable energy sources such as petroleum. These materials are complex to prepare and are difficult to degrade, causing environmental pollution.

[0003] As a clean and sustainable green energy, solar energy has become the focus of energy conversion and utilization in recent years. It has been widely used in photovoltaic power generation, photocatalysis and photothermal conversion. Among them, using the principle of photothermal conversion to improve the thermal insulation performance of materials is a low-cost, low-maintenance energy-saving technology. At present, the main photothermal conversion materials are carbon-based materials, plasmonic materials and semiconductor materials. Due to their own physical and chemical stability and high prices, their application is relatively limited. Among them, MXene (M n+1 AX n ) is a metal carbide and metal nitride material with a two-dimensional layered structure, the chemical formula is M n+1 AX n , where (n=13), M represents an early transition metal such as Sc, Ti, Zr, V, Nb, Cr, or Mo; A typically represents a chemical element from Group III or Group IV; and X represents an element such as C or N. MXene is a promising photothermal material. Studies have found that PDA-modified Ti3C2 exhibits not only excellent dispersibility but also high photothermal conversion efficiency and excellent thermal stability. Furthermore, Li et al. have demonstrated the high photothermal conversion efficiency of Ti3C2 nanosheets, and Chen et al. have demonstrated the excellent photothermal conversion function of PDA.

[0004] Aerogels are amorphous materials with a unique three-dimensional structure. Due to their high porosity, low apparent density, and low thermal conductivity, they are considered the best new solid thermal insulation material. With the increasing demand for green, energy-saving, and highly efficient thermal insulation materials, there is hope that effectively combining MXene with collagen could provide a low-cost, high-performance, safe, and environmentally friendly aerogel. This would provide excellent photothermal effects without compromising the aerogel's thermal insulation properties. Summary of the Invention

[0005] The object of the present invention is to provide a MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel and a preparation method thereof, wherein the prepared collagen aerogel has good photothermal conversion performance.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel comprises the following steps:

[0008] Step 1, first taking sodium carboxymethyl cellulose and sodium periodate in a mass ratio of 1: (0.5-3), then adding the sodium carboxymethyl cellulose and sodium periodate into deionized water respectively, stirring them thoroughly to completely dissolve them, mixing the aqueous solution of sodium carboxymethyl cellulose and the aqueous solution of sodium periodate to obtain a mixed solution A, then adjusting the pH value of the mixed solution A to acidic, and fully reacting at 20-60° C. to obtain a mixed solution B, adding anhydrous ethanol to the mixed solution B, and after precipitation, filtering, washing and freeze-drying in sequence to obtain dialdehyde carboxymethyl cellulose;

[0009] Step 2: Disperse 0.3 g of collagen in 35-50 mL of 0.5 mol / mL acetic acid solution to obtain a collagen solution;

[0010] Step 3: mixing dialdehyde carboxymethyl cellulose and the collagen solution in a mass ratio of collagen to dialdehyde carboxymethyl cellulose of 1:(0.05-0.2) to obtain a mixed solution C, and performing a cross-linking reaction in an ice-water bath to obtain a dialdehyde carboxymethyl cellulose-modified collagen solution;

[0011] Step 4: MXene and dopamine hydrochloride monomer are prepared in a mass ratio of 100:(2-10), MXene is dispersed in deionized water, and the pH value is adjusted to alkaline to obtain a MXene aqueous solution. The dopamine hydrochloride monomer is added to the MXene aqueous solution, stirred to fully react, and then freeze-dried to obtain a MXene@PDA solid powder;

[0012] Step 5: Add MXene@PDA solid to the dialdehyde carboxymethyl cellulose modified collagen solution according to the mass ratio of MXene@PDA solid powder to collagen of 1: (1 to 100), stir to fully react, and obtain a MXene@PDA / collagen composite suspension. After freeze-drying, a MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel is obtained.

[0013] Furthermore, the washing in step 1 is performed by alternating anhydrous ethanol and deionized water until the washing solution becomes neutral.

[0014] Furthermore, the reaction time of step 1 is 3 to 5 hours.

[0015] Furthermore, the pH value of the mixed solution C in step 3 is 5-8.

[0016] Furthermore, the cross-linking reaction time in step 3 is 2 to 24 hours.

[0017] Furthermore, the MXene in step 4 is Ti2C, Ti3C2, Mo2C, Mo2TiC or Mo2Ti2C3.

[0018] Furthermore, in step 4, the pH value of the MXene aqueous solution is adjusted to 7-8.5 using a NaOH aqueous solution.

[0019] Furthermore, the pH value of the MXene@PDA / collagen composite suspension in step 5 is 5-7.

[0020] Furthermore, the freeze-drying in step 5 is pre-freezing at -60 to -20°C for 4 to 72 hours, and then freeze-drying at -80°C for 24 to 72 hours.

[0021] A MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel.

[0022] The present invention has the following beneficial effects:

[0023] 1. The present invention successfully prepares dialdehyde carboxymethyl cellulose (DCMC) by oxidizing carboxymethyl cellulose with periodate. DCMC forms a Schiff base between -NH2 on collagen and -CHO in DCMC through a Schiff base reaction. Finally, collagen and DCMC form a composite structure, which improves the microstructure, chemical stability, mechanical properties and thermal insulation of the composite aerogel. At the same time, by modifying the MXene surface with polydopamine, not only the disadvantage of MXene's easy oxidation is effectively avoided, but the modification with polydopamine further promotes the photothermal conversion performance of MXene, which can be used for thermal insulation protection under normal or extreme conditions.

[0024] 2. The present invention uses freeze-drying to prepare collagen aerogel. The entire process is carried out at low temperature, which will not denature the collagen, allowing it to maintain the specific triple helix structure of collagen and maintain the excellent properties of the collagen itself.

[0025] 3. The main raw materials of the present invention, including collagen and sodium carboxymethyl cellulose, are environmentally friendly biomass materials with a wide range of sources. They will not pollute the environment, are green and friendly, and avoid secondary pollution during the preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1: XRD patterns of MXene and MXene@PDA prepared in Example 1 of the present invention;

[0027] Figure 2 : Scanning electron microscope (SEM) image of MXene prepared in Example 1 of the present invention;

[0028] Figure 3 : Scanning electron microscopy (SEM) image of MXene@PDA prepared in Example 1 of the present invention;

[0029] Figure 4 : Compressive stress-strain curves in the radial direction of the MXene@PDA-DCMC-COL aerogel prepared in Example 1 of the present invention at different MXene@PDA contents;

[0030] Figure 5 : Axial compressive stress-strain curves of the MXene@PDA-DCMC-COL aerogel prepared in Example 1 of the present invention at different MXene@PDA contents;

[0031] Figure 6 Thermal infrared images of the MXene@PDA-DCMC-COL aerogel prepared in Example 1 of the present invention in the radial (a) and axial (b) directions after heating on a heating table at 140°C for 5 min, 10 min, 15 min, and 20 min.

[0032] Figure 7 Thermal infrared images of the MXene@PDA-DCMC-COL aerogel prepared in Example 1 of the present invention in the radial (e) and axial (d) directions after heating on a heating table at 140°C for 60 min.

[0033] Figure 8 : Temperature-time evolution curve of MXene@PDA-DCMC-COL aerogel prepared in Example 1 of the present invention on a heating platform at 140°C;

[0034] Figure 9 Thermal infrared images of the MXene@PDA-DCMC-COL aerogel prepared in Example 1 of the present invention in the radial (a) and axial (b) directions after being placed on an ice pack at -17°C for 5, 10, and 15 minutes.

[0035] Figure 10 : Temperature-time evolution curve of the MXene@PDA-DCMC-COL aerogel prepared in Example 1 of the present invention on an ice pack at -17°C;

[0036] Figure 11: Graph showing the radial photothermal conversion performance of the MXene@PDA-DCMC-COL aerogel prepared in Example 1 of the present invention and conventional DCMC-COL aerogel. DETAILED DESCRIPTION

[0037] The specific contents of the present invention are further explained in detail below with reference to the embodiments, but are not intended to limit the present invention.

[0038] Examples 1 to 6 of the present invention all refer to the preparation and photothermal conversion performance of MXene / CNF composite aerogels by Huang Junwen, Tang Feng, Li Yingzhan, Zhou Ying, Yu Houyong and Yao Juming, and the MXene required for the experiment was prepared by selective etching with HCl and lithium fluoride.

[0039] Example 1

[0040] Step 1. First, sodium carboxymethyl cellulose and sodium periodate are taken in a mass ratio of 1:0.5, and then the sodium carboxymethyl cellulose and sodium periodate are added to deionized water respectively. After fully stirring to completely dissolve them, the aqueous solution of sodium carboxymethyl cellulose and the aqueous solution of sodium periodate are mixed to obtain a mixed solution A, and then the pH value of the mixed solution A is adjusted to 1.5, and the mixture is fully reacted at 20°C for 3 hours to obtain a mixed solution B. Anhydrous ethanol is added to the mixed solution B. After the precipitate is precipitated, it is first filtered, and then alternately washed with anhydrous ethanol and deionized water until the washing solution is neutral, and then freeze-dried at -80°C for 24 hours to obtain dialdehyde carboxymethyl cellulose;

[0041] Step 2: Disperse 0.3 g of collagen in 35 mL of 0.5 mol / mL acetic acid solution to obtain a collagen solution;

[0042] Step 3: According to the mass ratio of collagen to dialdehyde carboxymethyl cellulose of 1:0.05, dialdehyde carboxymethyl cellulose and the collagen solution were mixed evenly to obtain a mixed solution C, and the pH value thereof was adjusted to 6.5. The mixture was cross-linked in an ice water bath for 24 hours to obtain a dialdehyde carboxymethyl cellulose-modified collagen solution;

[0043] Step 4: Ti3C2 and dopamine hydrochloride monomer are prepared in a mass ratio of 100:2, Ti3C2 is dispersed in deionized water, and the pH value is adjusted to 7 to obtain a Ti3C2 aqueous solution. The dopamine hydrochloride monomer is added to the Ti3C2 aqueous solution, stirred to fully react, and then freeze-dried at -80°C for 12 hours to obtain Ti3C2@PDA solid powder;

[0044] Step 5. According to the mass ratio of Ti3C2@PDA solid powder to collagen of 1:1, the Ti3C2@PDA solid was added to the dialdehyde carboxymethyl cellulose modified collagen solution, and stirred to fully react to obtain a Ti3C2@PDA / collagen composite suspension. The pH value was adjusted to 5, and the suspension was pre-frozen at -60°C for 4 hours and then dried at -80°C for 72 hours to obtain the Ti3C2@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel.

[0045] from Figure 1 It can be seen that compared with the original Ti3AlC2 sample, the characteristic peak of the aluminum crystal plane at 2θ=39° in the MXene sample (Ti3C2) prepared by etching and ultrasonic-assisted exfoliation indicates that the Al layer has been etched away, and the (002) characteristic peak of MXene moves from 9.6° to 6.8°, indicating that the carbon lattice spacing is increased. The results show that MXene has been successfully prepared;

[0046] from Figure 2 It can be seen that the MXene (Ti3C2) after selective etching with LiF / HCl is a thin nanosheet structure with a smooth and clean surface and very thin wrinkles, while the original Ti3AlC2 is a tightly stacked lamellar structure with very close layers and no pores. This is because after chemical etching removes the Al layer in Ti3AlC2, the stacked layers can be further peeled off into few-layer or single-layer MXene (Ti3C2) by ultrasound.

[0047] from Figure 3 It can be seen that the Ti3C2@PDA nanosheets are as thin as cicada wings, and the Tyndall effect was observed in the Ti3C2@PDA dispersion during the experiment, indicating its colloidal characteristics. Figure 1 The XRD test results can prove that MXene (Ti3C2) has been successfully prepared.

[0048] from Figure 4 and Figure 5 It can be seen that with the increase of Ti3C2@PDA content, the number of Schiff base bonds generated increases, the cross-linking density also increases, and the mechanical properties of the aerogel are significantly improved.

[0049] from Figure 6 and Figure 7It can be seen that a 25 mm thick MXene@PDA-DCMC-COL aerogel sample was placed on a heating table at 140°C, and the surface temperature of the sample was recorded for 20 minutes using an infrared thermal imager, and recorded using a multi-channel thermometer with a thermocouple. After being placed on a heating table at 140°C for 5 minutes, the surface temperatures of the MXene@PDA-DCMC-COL aerogel in the radial (a) and axial (b) directions were 35°C and 40.0°C, respectively; after heating for 20 minutes, the surface temperatures of the aerogel in the radial (a) and axial (b) directions rose slightly to 36.9°C and 42.9°C, respectively; after heating for 60 minutes, the surface temperatures of the aerogel in the radial (a) and axial (b) directions were 44.9 and 51.5°C, respectively, which were still far lower than the heating table temperature of 140°C.

[0050] from Figure 8 It can be seen that the surface temperature of the aerogel in the radial direction is always lower than the surface temperature in the axial direction, indicating that the MXene@PDA-DCMC-COL aerogel has good thermal insulation properties, and the thermal insulation effect of the MXene@PDA-DCMC-COL aerogel in the radial direction is even better.

[0051] from Figure 9 It can be seen that when a 25 mm thick MXene@PDA-DCMC-COL aerogel sample is placed on an ice pack at -17°C, after 5 minutes, the surface temperatures of the MXene@PDA-DCMC-COL aerogel in the radial (a) and axial (b) directions are 19.9°C and 17.2°C, respectively, which are 3.1°C and 5.8°C lower than the initial temperature of the sample of 23.0°C; after 10 minutes, the surface temperatures of the aerogel in the radial (a) and axial (b) directions are 19.0°C and 16.8°C, respectively; after 20 minutes, as the temperature of the ice pack increases slightly, the surface temperature of the aerogel sample also increases slightly. At this time, the surface temperatures of the aerogel in the radial (a) and axial (b) directions are 19.4°C and 17.3°C, respectively, but are still much higher than the temperature of the ice pack of -17°C.

[0052] from Figure 10 It can be seen that the surface temperature of the aerogel in the radial direction is always higher than that in the axial direction, indicating that the MXene@PDA-DCMC-COL aerogel has good thermal insulation performance, and its thermal insulation effect in the radial direction is even better.

[0053] from Figure 11 Xenon lamp is used to simulate sunlight, and the light intensity is 100mW / cm 2The photothermal conversion performance of DCMC-COL aerogel and MXene@PDA-DCMC-COL aerogel in the radial direction is shown in the figure. It can be seen from the figure that after 15 minutes of irradiation, both DCMC-COL aerogel and MXene@PDA-DCMC-COL aerogel reached equilibrium temperatures of 37.7°C and 57.9°C, respectively. The temperature of MXene@PDA-DCMC-COL aerogel is 20.5°C higher than that of DCMC-COL aerogel without MXene@PDA. This is because the DCMC-COL aerogel system does not have an effective light-absorbing structure, while MXene@PDA is an effective light absorber and heating unit that can convert solar energy into thermal energy. The introduction of MXene@PDA gives it excellent photothermal conversion performance.

[0054] Example 2

[0055] Step 1. First, sodium carboxymethyl cellulose and sodium periodate are taken in a mass ratio of 1:1, and then the sodium carboxymethyl cellulose and sodium periodate are added to deionized water respectively. After fully stirring to completely dissolve them, the aqueous solution of sodium carboxymethyl cellulose and the aqueous solution of sodium periodate are mixed to obtain a mixed solution A. The pH value of the mixed solution A is adjusted to 2.5, and the mixture is fully reacted at 30° C. for 3.5 hours to obtain a mixed solution B. Anhydrous ethanol is added to the mixed solution B. After the precipitate is precipitated, it is first filtered, and then alternately washed with anhydrous ethanol and deionized water until the washing solution is neutral, and then freeze-dried at -80° C. for 20 hours to obtain dialdehyde carboxymethyl cellulose;

[0056] Step 2: Disperse 0.3 g of collagen in 40 mL of 0.5 mol / mL acetic acid solution to obtain a collagen solution;

[0057] Step 3: According to the mass ratio of collagen to dialdehyde carboxymethyl cellulose of 1:0.1, dialdehyde carboxymethyl cellulose and the collagen solution were mixed evenly to obtain a mixed solution C, and the pH value thereof was adjusted to 5.5. The mixed solution was cross-linked in an ice water bath for 18 hours to obtain a dialdehyde carboxymethyl cellulose-modified collagen solution;

[0058] Step 4: Ti2C and dopamine hydrochloride monomers were prepared in a mass ratio of 100:4, and Ti2C was dispersed in deionized water. The pH value was adjusted to 7.5 to obtain a Ti2C aqueous solution. The dopamine hydrochloride monomer was added to the Ti2C aqueous solution, stirred to fully react, and then freeze-dried at -80°C for 14 hours to obtain Ti2C@PDA solid powder.

[0059] Step 5. According to the mass ratio of Ti2C@PDA solid powder to collagen of 1:50, Ti2C@PDA solid was added to the dialdehyde carboxymethyl cellulose modified collagen solution, and stirred to fully react to obtain a Ti2C@PDA / collagen composite suspension. The pH value was adjusted to 6, and the suspension was pre-frozen at -40°C for 24 hours and then dried at -80°C for 60 hours to obtain Ti2C@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel.

[0060] Example 3

[0061] Step 1. First, sodium carboxymethyl cellulose and sodium periodate are taken in a mass ratio of 1:1.5, and then the sodium carboxymethyl cellulose and sodium periodate are added to deionized water respectively. After fully stirring to completely dissolve them, the aqueous solution of sodium carboxymethyl cellulose and the aqueous solution of sodium periodate are mixed to obtain a mixed solution A. The pH value of the mixed solution A is adjusted to 3, and the mixture is fully reacted at 40°C for 4 hours to obtain a mixed solution B. Anhydrous ethanol is added to the mixed solution B. After the precipitate is precipitated, it is first filtered, and then alternately washed with anhydrous ethanol and deionized water until the washing solution is neutral, and then freeze-dried at -80°C for 18 hours to obtain dialdehyde carboxymethyl cellulose;

[0062] Step 2: Disperse 0.3 g of collagen in 45 mL of 0.5 mol / mL acetic acid solution to obtain a collagen solution;

[0063] Step 3: According to the mass ratio of collagen to dialdehyde carboxymethyl cellulose of 1:0.15, dialdehyde carboxymethyl cellulose and the collagen solution were mixed evenly to obtain a mixed solution C, and the pH value thereof was adjusted to 5. The mixed solution was cross-linked in an ice water bath for 12 hours to obtain a dialdehyde carboxymethyl cellulose-modified collagen solution;

[0064] Step 4: Mo2C and dopamine hydrochloride monomers were prepared in a mass ratio of 100:6, and the Mo2C was dispersed in deionized water and the pH value was adjusted to 8 to obtain a Mo2C aqueous solution. The dopamine hydrochloride monomer was added to the Mo2C aqueous solution, stirred to fully react, and then freeze-dried at -80°C for 16 hours to obtain Mo2C@PDA solid powder;

[0065] Step 5. According to the mass ratio of Mo2C@PDA solid powder to collagen of 1:20, Mo2C@PDA solid was added to the dialdehyde carboxymethyl cellulose modified collagen solution, and stirred to fully react to obtain a Mo2C@PDA / collagen composite suspension. The pH value was adjusted to 7, and the suspension was pre-frozen at -20°C for 60 h and then dried at -80°C for 48 h to obtain Mo2C@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel.

[0066] Example 4

[0067] Step 1. First, sodium carboxymethyl cellulose and sodium periodate are taken in a mass ratio of 1:2, and then the sodium carboxymethyl cellulose and sodium periodate are respectively added to deionized water, and after being fully stirred to completely dissolve, the aqueous solution of sodium carboxymethyl cellulose and the aqueous solution of sodium periodate are mixed to obtain a mixed solution A, and then the pH value of the mixed solution A is adjusted to 4, and the mixture is fully reacted at 50° C. for 4.5 hours to obtain a mixed solution B, and anhydrous ethanol is added to the mixed solution B. After the precipitate is precipitated, it is first filtered, and then alternately washed with anhydrous ethanol and deionized water until the washing solution is neutral, and then freeze-dried at -80° C. for 16 hours to obtain dialdehyde carboxymethyl cellulose;

[0068] Step 2: Disperse 0.3 g of collagen in 50 mL of 0.5 mol / mL acetic acid solution to obtain a collagen solution;

[0069] Step 3: According to the mass ratio of collagen to dialdehyde carboxymethyl cellulose of 1:0.2, dialdehyde carboxymethyl cellulose and the collagen solution were mixed evenly to obtain a mixed solution C, and the pH value thereof was adjusted to 6. The mixed solution was cross-linked in an ice water bath for 6 hours to obtain a dialdehyde carboxymethyl cellulose-modified collagen solution;

[0070] Step 4: Mo2TiC and dopamine hydrochloride monomers were prepared in a mass ratio of 100:8, and the Mo2TiC was dispersed in deionized water. The pH value was adjusted to 8.5 to obtain a Mo2TiC aqueous solution. The dopamine hydrochloride monomer was added to the Mo2TiC aqueous solution, stirred to fully react, and then freeze-dried at -80°C for 18 hours to obtain a Mo2TiC@PDA solid powder.

[0071] Step 5. According to the mass ratio of Mo2TiC@PDA solid powder to collagen of 1:80, Mo2TiC@PDA solid was added to the dialdehyde carboxymethyl cellulose modified collagen solution, and stirred to fully react to obtain a Mo2TiC@PDA / collagen composite suspension. The pH value was adjusted to 7, and the suspension was pre-frozen at -25°C for 36 hours and then dried at -80°C for 36 hours to obtain Mo2TiC@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel.

[0072] Example 5

[0073] Step 1. First, sodium carboxymethyl cellulose and sodium periodate are taken in a mass ratio of 1:2.5, and then the sodium carboxymethyl cellulose and sodium periodate are added to deionized water respectively. After fully stirring to completely dissolve them, the aqueous solution of sodium carboxymethyl cellulose and the aqueous solution of sodium periodate are mixed to obtain a mixed solution A. The pH value of the mixed solution A is adjusted to 5, and the mixture is fully reacted at 60° C. for 5 hours to obtain a mixed solution B. Anhydrous ethanol is added to the mixed solution B. After the precipitate is precipitated, it is first filtered, and then alternately washed with anhydrous ethanol and deionized water until the washing solution is neutral, and then freeze-dried at -80° C. for 14 hours to obtain dialdehyde carboxymethyl cellulose;

[0074] Step 2: Disperse 0.3 g of collagen in 42 mL of 0.5 mol / mL acetic acid solution to obtain a collagen solution;

[0075] Step 3: According to the mass ratio of collagen to dialdehyde carboxymethyl cellulose of 1:0.12, dialdehyde carboxymethyl cellulose and the collagen solution were mixed evenly to obtain a mixed solution C, and the pH value thereof was adjusted to 7. The mixed solution was cross-linked in an ice water bath for 20 hours to obtain a dialdehyde carboxymethyl cellulose-modified collagen solution;

[0076] Step 4: Mo2Ti2C3 and dopamine hydrochloride monomer are taken in a mass ratio of 100:10, Mo2Ti2C3 is dispersed in deionized water, and the pH value is adjusted to 7 to obtain a Mo2Ti2C3 aqueous solution. The dopamine hydrochloride monomer is added to the Mo2Ti2C3 aqueous solution, stirred to fully react, and then freeze-dried at -80°C for 20 hours to obtain Mo2Ti2C3@PDA solid powder;

[0077] Step 5. According to the mass ratio of Mo2Ti2C3@PDA solid powder to collagen of 1:100, Mo2Ti2C3@PDA solid was added to the dialdehyde carboxymethyl cellulose modified collagen solution, and stirred to fully react to obtain a Mo2Ti2C3@PDA / collagen composite suspension. The pH value was adjusted to 5.5, and the suspension was pre-frozen at -50°C for 48 hours and then dried at -80°C for 24 hours to obtain Mo2Ti2C3@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel.

[0078] Example 6

[0079] Step 1. First, sodium carboxymethyl cellulose and sodium periodate are taken in a mass ratio of 1:3, and then the sodium carboxymethyl cellulose and sodium periodate are added to deionized water respectively. After fully stirring to completely dissolve them, the aqueous solution of sodium carboxymethyl cellulose and the aqueous solution of sodium periodate are mixed to obtain a mixed solution A. The pH value of the mixed solution A is adjusted to 3.5, and the mixture is fully reacted at 35° C. for 5 hours to obtain a mixed solution B. Anhydrous ethanol is added to the mixed solution B. After the precipitate is precipitated, it is first filtered, and then alternately washed with anhydrous ethanol and deionized water until the washing solution is neutral, and then freeze-dried at -80° C. for 12 hours to obtain dialdehyde carboxymethyl cellulose;

[0080] Step 2: Disperse 0.3 g of collagen in 38 mL of 0.5 mol / mL acetic acid solution to obtain a collagen solution;

[0081] Step 3: According to the mass ratio of collagen to dialdehyde carboxymethyl cellulose of 1:0.13, dialdehyde carboxymethyl cellulose and the collagen solution were mixed evenly to obtain a mixed solution C, and the pH value thereof was adjusted to 8. The mixture was cross-linked in an ice water bath for 2 hours to obtain a dialdehyde carboxymethyl cellulose-modified collagen solution;

[0082] Step 4: Ti3C2 and dopamine hydrochloride monomer are taken in a mass ratio of 100:5, Ti3C2 is dispersed in deionized water, and the pH value is adjusted to 8.5 to obtain a Ti3C2 aqueous solution. The dopamine hydrochloride monomer is added to the Ti3C2 aqueous solution, stirred to fully react, and then freeze-dried at -80°C for 24 hours to obtain Ti3C2@PDA solid powder;

[0083] Step 5. According to the mass ratio of Ti3C2@PDA solid powder to collagen of 1:60, Ti3C2@PDA solid was added to the dialdehyde carboxymethyl cellulose modified collagen solution, and stirred to fully react to obtain a Ti3C2@PDA / collagen composite suspension. The pH value was adjusted to 6.5, and the suspension was pre-frozen at -50°C for 72 hours and then dried at -80°C for 30 hours to obtain Ti3C2@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel.

Claims

1. A method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel, characterized in that: The steps include: Step 1, first taking sodium carboxymethyl cellulose and sodium periodate in a mass ratio of 1: (0.5-3), then adding the sodium carboxymethyl cellulose and sodium periodate into deionized water respectively, stirring them thoroughly to completely dissolve them, mixing the aqueous solution of sodium carboxymethyl cellulose and the aqueous solution of sodium periodate to obtain a mixed solution A, then adjusting the pH value of the mixed solution A to acidic, and fully reacting at 20-60° C. to obtain a mixed solution B, adding anhydrous ethanol to the mixed solution B, and after precipitation, filtering, washing and freeze-drying in sequence to obtain dialdehyde carboxymethyl cellulose; Step 2: Disperse 0.3 g of collagen in 35-50 mL of 0.5 mol / mL acetic acid solution to obtain a collagen solution; Step 3: mixing dialdehyde carboxymethyl cellulose and the collagen solution in a mass ratio of collagen to dialdehyde carboxymethyl cellulose of 1:(0.05-0.2) to obtain a mixed solution C, and performing a cross-linking reaction in an ice-water bath to obtain a dialdehyde carboxymethyl cellulose-modified collagen solution; Step 4: MXene and dopamine hydrochloride monomer are prepared in a mass ratio of 100:(2-10), MXene is dispersed in deionized water, and the pH value is adjusted to alkaline to obtain a MXene aqueous solution. The dopamine hydrochloride monomer is added to the MXene aqueous solution, stirred to fully react, and then freeze-dried to obtain a MXene@PDA solid powder; Step 5: Add MXene@PDA solid to the dialdehyde carboxymethyl cellulose modified collagen solution according to the mass ratio of MXene@PDA solid powder to collagen of 1: (1 to 100), stir to fully react, and obtain a MXene@PDA / collagen composite suspension. After freeze-drying, a MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel is obtained.

2. The method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel according to claim 1, characterized in that: The washing in step 1 is performed by alternately washing with anhydrous ethanol and deionized water until the washing solution is neutral.

3. The method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel according to claim 1, characterized in that: The reaction time of step 1 is 3 to 5 hours.

4. The method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel according to claim 1, characterized in that: The pH value of the mixed solution C in step 3 is 5-8.

5. The method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel according to claim 1, characterized in that: The cross-linking reaction time in step 3 is 2 to 24 hours.

6. The method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel according to claim 1, characterized in that: The MXene in step 4 is Ti2C, Ti3C2, Mo2C, Mo2TiC or Mo2Ti2C3.

7. The method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel according to claim 1, characterized in that: In step 4, the pH value of the MXene aqueous solution is adjusted to 7-8.5 using a NaOH aqueous solution.

8. The method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel according to claim 1, characterized in that: The pH value of the MXene@PDA / collagen composite suspension in step 5 is 5-7.

9. The method for preparing MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel according to claim 1, characterized in that: The freeze drying in step 5 is performed by pre-freezing at -60 to -20°C for 4 to 72 hours, and then freeze drying at -80°C for 24 to 72 hours.

10. A MXene@PDA / dialdehyde carboxymethyl cellulose modified collagen aerogel prepared by the method according to any one of claims 1 to 9.

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