A method for preparing MXene / CS aerogel
By controlling the mass ratio of MXene and chitosan to 1:30 or 1:120 and freeze-drying under specific conditions, MXene/CS aerogels with excellent mechanical properties and self-healing effects were prepared, solving the problems of poor cross-linking and unsatisfactory healing effects in the existing technology, and achieving rapid healing and excellent mechanical properties.
Patent Information
- Application Number
- CN202310661526.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-06
- Publication Date
- 2025-10-14
- Estimated Expiration
- 2043-06-06
AI Technical Summary
It is difficult to prepare MXene/CS aerogels with excellent mechanical properties and self-healing effects with existing technologies, especially when the cross-linking effect is poor or the healing effect is not ideal at different mass ratios.
MXene/CS aerogels were prepared by controlling the mass ratio of MXene to chitosan to 1:30 or 1:120 and performing freeze-drying treatment under specific conditions. The specific steps included dissolving chitosan in glacial acetic acid and mixing it with MXene, followed by freezing at low temperatures and freeze-drying.
The MXene/CS aerogel achieved rapid healing in a wet state and excellent mechanical properties. In particular, the aerogel with a ratio of 1:120 was able to achieve complete healing within 20 seconds, showing excellent mechanical properties and self-healing effects.
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Figure CN116874871B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of nanoporous material preparation and relates to a method for preparing MXene / CS aerogel. Background Art
[0002] The preparation of aerogels involves a sol-gel process, freezing, and freeze-drying. A sol is dissolved in a suitable solvent to form a sol. The sol is then converted into a gel through a gelation process, either by adding a gelling agent or by modifying the chemical properties of the sol. The gel is then placed in a low-temperature environment, rapidly cooled and frozen to form ice crystals, converting the solvent from the gel into an ice phase. While frozen, the gel is placed in a vacuum environment and subjected to appropriate heat and pressure for freeze-drying. In this step, the frozen water is removed by sublimation at low temperatures, removing water from the gel without passing through the liquid phase. This process, called sublimation, converts the water from the gel into a gas, allowing the gel to retain its pore structure and morphology. Through these steps, the gel prepared by freeze-drying retains its pore structure and morphology, transforming into an aerogel. Freeze-drying technology can effectively control the pore structure and physical properties of aerogels and is commonly used to prepare high-performance aerogel materials. Summary of the Invention
[0003] In view of this, the present invention provides a method for preparing MXene / CS aerogel. The present invention specifically provides the following technical solutions:
[0004] A method for preparing MXene / CS aerogel, comprising the following steps:
[0005] 1) Preparation of single-layer two-dimensional transition metal carbide MXene using LiF and Ti3AlC2;
[0006] 2) Dissolving chitosan in glacial acetic acid, adding the MXene obtained in step 1) with a mass ratio of MXene to chitosan of 1:30 to 1:120, stirring, transferring the solution to a sub-zero refrigerator for freezing, and then freeze-drying to obtain a MXene / CS aerogel.
[0007] Furthermore, step 1) is to mix LiF and Ti3AlC2 in hydrochloric acid for etching and stirring, centrifugation and washing until the pH is neutral, then gas washing and ultrasonic peeling, centrifugation to obtain Ti3C2Tx nanosheet colloidal solution, and freeze-drying to obtain a powder product.
[0008] Furthermore, the mass ratio of LiF and Ti3AlC2 powder in step 1) is 1:1.
[0009] Furthermore, the stirring in step 1) is carried out for 24 to 26 hours, and the temperature is controlled at 30 to 35°C.
[0010] Further, the mass ratio of MXene and chitosan in step 2) is 1:30 and 1:120.
[0011] Further, the viscosity of chitosan in step 2) is > 400 mPa.s.
[0012] Further, the stirring time in step 2) is 24-30 hours.
[0013] Further, the refrigerator temperature in step 2) is -70 to -80 DEG C.
[0014] Further, the freezing time in step 2) is 12-20 hours.
[0015] The beneficial effects of the present application are that the present application prepares aerogels with different MXene and chitosan mass ratios (6:1, 3:1, 1:1, 1:2, 1:3, 1:30, 1:120), and by comparing the products, it is found that the products with a ratio of 6:1 and 3:1 have poor gelation effect and even cannot perform healing experiments; the products with a ratio of 1:1, 1:2 and 1:3 have improved mechanical properties but poor healing effect; the products with a ratio of 1:30 and 1:120 have good mechanical properties and healing effect, and the product with a ratio of 1:120 has the best healing effect, which can achieve healing in 20s in a wet state. BRIEF DESCRIPTION OF DRAWINGS
[0016] In order to make the purpose, technical scheme and beneficial effects of the present application clearer, the present application provides the following drawings:
[0017] Figure 1 Figure is the pressure rebound test diagram of MXene / CS aerogel.
[0018] Figure 2 Figure is the self-healing performance test diagram of MXene / CS aerogel. DETAILED DESCRIPTION
[0019] The preferred embodiments of the present application are described in detail below with reference to the drawings.
[0020] Example 1
[0021] The preparation of MXene / CS aerogel is as follows:
[0022] 1) Preparation of MXene
[0023] Pour 30mL of hydrochloric acid into a beaker and add 10mL of deionized water. Add 2g of LiF to the beaker and start magnetic stirring. Then add 2g of Ti3AlC2 powder to the beaker ten times within 30 minutes, and then magnetically stir for 10 minutes. Transfer the reactor to an oil bath and react with magnetic stirring for 24 hours, with the temperature controlled at 35°C. Then centrifuge and wash the solution until the pH reaches neutral. After centrifugation, pass inert gas (argon) into the Ti3AlC2 and perform ultrasonic exfoliation. Centrifuge the Ti3C2Tx solution after ultrasonic exfoliation for 1 hour at a speed of 3500rpm. The final supernatant is a colloidal solution of Ti3C2Tx nanosheets, which is finally freeze-dried to obtain a powder product.
[0024] 2) Preparation of MXene / CS aerogel
[0025] Chitosan (CS, viscosity >400 mPa·s) was dissolved in glacial acetic acid and the MXene powder obtained in step 1) was added, with a mass ratio of MXene to chitosan of 6:1. The mixture was magnetically stirred for 24 hours, then transferred to a -80°C freezer and frozen for 12 hours. Finally, freeze-dried to obtain MXene / CS aerogel P1.
[0026] Example 2
[0027] The preparation steps of MXene / CS aerogel are as follows:
[0028] 1) Preparation of MXene
[0029] Pour 30mL of hydrochloric acid into a beaker and add 10mL of deionized water. Add 2g of LiF to the beaker and start magnetic stirring. Then add 2g of Ti3AlC2 powder to the beaker ten times within 30 minutes, and then magnetically stir for 10 minutes. Transfer the reactor to an oil bath and react with magnetic stirring for 24 hours, with the temperature controlled at 35°C. Then centrifuge and wash the solution until the pH reaches neutral. After centrifugation, pass inert gas (argon) into the Ti3AlC2 and perform ultrasonic exfoliation. Centrifuge the Ti3C2Tx solution after ultrasonic exfoliation for 1 hour at a speed of 3500rpm. The final supernatant is a colloidal solution of Ti3C2Tx nanosheets, which is finally freeze-dried to obtain a powder product.
[0030] 2) Preparation of MXene / CS aerogel
[0031] Chitosan (CS, viscosity >400 mPa·s) was dissolved in glacial acetic acid and the MXene powder obtained in step 1) was added, with a mass ratio of MXene to chitosan of 3:1. The mixture was magnetically stirred for 24 hours, then transferred to a -80°C freezer and frozen for 12 hours. Finally, freeze-dried to obtain MXene / CS aerogel P2.
[0032] Example 3
[0033] The preparation steps of MXene / CS aerogel are as follows:
[0034] 1) Preparation of MXene
[0035] Pour 30mL of hydrochloric acid into a beaker and add 10mL of deionized water. Add 2g of LiF to the beaker and start magnetic stirring. Then add 2g of Ti3AlC2 powder to the beaker ten times within 30 minutes, and then magnetically stir for 10 minutes. Transfer the reactor to an oil bath and react with magnetic stirring for 24 hours, with the temperature controlled at 35°C. Then centrifuge and wash the solution until the pH reaches neutral. After centrifugation, pass inert gas (argon) into the Ti3AlC2 and perform ultrasonic exfoliation. Centrifuge the Ti3C2Tx solution after ultrasonic exfoliation for 1 hour at a speed of 3500rpm. The final supernatant is a colloidal solution of Ti3C2Tx nanosheets, which is finally freeze-dried to obtain a powder product.
[0036] 2) Preparation of MXene / CS aerogel
[0037] Chitosan (CS, viscosity >400 mPa·s) was dissolved in glacial acetic acid and the MXene powder obtained in step 1) was added, with a mass ratio of MXene to chitosan of 1:1. The mixture was magnetically stirred for 24 hours, then transferred to a -80°C freezer and frozen for 12 hours. Finally, freeze-dried to obtain MXene / CS aerogel P3.
[0038] Example 4
[0039] The preparation steps of MXene / CS aerogel are as follows:
[0040] 1) Preparation of MXene
[0041] Pour 30mL of hydrochloric acid into a beaker and add 10mL of deionized water. Add 2g of LiF to the beaker and start magnetic stirring. Then add 2g of Ti3AlC2 powder to the beaker ten times within 30 minutes, and then magnetically stir for 10 minutes. Transfer the reactor to an oil bath and react with magnetic stirring for 24 hours, with the temperature controlled at 35°C. Then centrifuge and wash the solution until the pH reaches neutral. After centrifugation, pass inert gas (argon) into the Ti3AlC2 and perform ultrasonic exfoliation. Centrifuge the Ti3C2Tx solution after ultrasonic exfoliation for 1 hour at a speed of 3500rpm. The final supernatant is a colloidal solution of Ti3C2Tx nanosheets, which is finally freeze-dried to obtain a powder product.
[0042] 2) Preparation of MXene / CS aerogel
[0043] Chitosan (CS, viscosity >400 mPa·s) was dissolved in glacial acetic acid and the MXene powder obtained in step 1) was added, with a mass ratio of MXene to chitosan of 1:2. The mixture was magnetically stirred for 24 hours, then transferred to a -80°C freezer and frozen for 12 hours. Finally, freeze-dried to obtain MXene / CS aerogel P4.
[0044] Example 5
[0045] The preparation steps of MXene / CS aerogel are as follows:
[0046] 1) Preparation of MXene
[0047] Pour 30mL of hydrochloric acid into a beaker and add 10mL of deionized water. Add 2g of LiF to the beaker and start magnetic stirring. Then add 2g of Ti3AlC2 powder to the beaker ten times within 30 minutes, and then magnetically stir for 10 minutes. Transfer the reactor to an oil bath and react with magnetic stirring for 24 hours, with the temperature controlled at 35°C. Then centrifuge and wash the solution until the pH reaches neutral. After centrifugation, pass inert gas (argon) into the Ti3AlC2 and perform ultrasonic exfoliation. Centrifuge the Ti3C2Tx solution after ultrasonic exfoliation for 1 hour at a speed of 3500rpm. The final supernatant is a colloidal solution of Ti3C2Tx nanosheets, which is finally freeze-dried to obtain a powder product.
[0048] 2) Preparation of MXene / CS aerogel
[0049] Chitosan (CS, viscosity >400 mPa·s) was dissolved in glacial acetic acid and the MXene powder obtained in step 1) was added, with a mass ratio of MXene to chitosan of 1:30. The mixture was magnetically stirred for 24 hours, then transferred to a -80°C freezer and frozen for 12 hours. Finally, freeze-dried to obtain MXene / CS aerogel P5.
[0050] Example 6
[0051] The preparation steps of MXene / CS aerogel are as follows:
[0052] 1) Preparation of MXene
[0053] Pour 30mL of hydrochloric acid into a beaker and add 10mL of deionized water. Add 2g of LiF to the beaker and start magnetic stirring. Then add 2g of Ti3AlC2 powder to the beaker ten times within 30 minutes, and then magnetically stir for 10 minutes. Transfer the reactor to an oil bath and react with magnetic stirring for 24 hours, with the temperature controlled at 35°C. Then centrifuge and wash the solution until the pH reaches neutral. After centrifugation, pass inert gas (argon) into the Ti3AlC2 and perform ultrasonic exfoliation. Centrifuge the Ti3C2Tx solution after ultrasonic exfoliation for 1 hour at a speed of 3500rpm. The final supernatant is a colloidal solution of Ti3C2Tx nanosheets, which is finally freeze-dried to obtain a powder product.
[0054] 2) Preparation of MXene / CS aerogel
[0055] Chitosan (CS, viscosity >400 mPa·s) was dissolved in glacial acetic acid and the MXene powder obtained in step 1) was added, with a mass ratio of MXene to chitosan of 1:120. The mixture was magnetically stirred for 24 hours, then transferred to a -80°C freezer and frozen for 12 hours. Finally, freeze-dried to obtain MXene / CS aerogel P6.
[0056] Test Example 1: Pressure Rebound Test
[0057] Under dry conditions at room temperature, place a 90g weight on the sample, wait for 10 seconds, then remove the weight and observe whether the sample will rebound and its rebound time. Figure 1 As shown, Figure 1 (a) is the P1 and P2 samples, Figure 1 (b) is a photo of the P3 sample before and after compression. Figure 1 (c) is a photo of the P4 sample before and after compression. Figure 1 (d) is a photo of the P5 sample before and after compression. Figure 1 (e) Photos of the P6 sample before and after compression.
[0058] from Figure 1 As can be seen from the results, P1 and P2 were too brittle to withstand pressure testing due to poor crosslinking. P3 and P4 had significantly improved mechanical properties, being compressible but unable to fully rebound, with approximately 50% rebound after 5 seconds. P5 fully rebounded after 5 seconds, demonstrating excellent rebound performance. P6 rebounded immediately after 1 second of compression, demonstrating even better rebound performance than P5.
[0059] Test Example 2: Self-healing test
[0060] Under dry conditions at room temperature, cut the sample, moisten the cut surface with water using a spray bottle, then put the two cut parts in contact to observe whether the sample is healed. Figure 2 As shown, Figure 2 (a) is the P1 and P2 samples, Figure 2 (b) is a photo of the self-healing process of the P3 sample. Figure 2 (c) is a photo of the self-healing process of the P4 sample. Figure 2 (d) is a photo of the self-healing process of the P5 sample. Figure 2 (e) is a photo of the 30s self-healing process of the P6 sample. Figure 2 (f) is a photo of the 20s self-healing process of the P6 sample.
[0061] from Figure 2 As can be seen from (a), P1 and P2 cannot be tested for healing due to poor cross-linking effects. Figure 2 As can be seen from (b) and (c), P3 and P4 can be healed after 2 minutes of wetting, but the samples become soft and thin after absorbing water, and the effect is poor. Figure 2 In (d), we can see that P5 heals after 1 minute of wetting. The connection is tight after healing, and the fracture surface when trying to tear it apart by stretching is not at the healing position. Figure 2 (e) It can be seen that P6 was wetted and contacted after incision, and healed within 30s, with a tight connection at the healed site. Figure 2 As can be seen in (f), the P6 sample heals within 20 seconds after being cut and moistened. The healing is tight and the healing marks are shallow, indicating better healing than the P5.
Claims
1. A method for preparing MXene / CS aerogel, characterized in that: Here are the steps: 1) LiF and Ti3AlC2 were mixed and etched in hydrochloric acid and stirred, centrifuged and washed until the pH was neutral, then gas-washed and ultrasonically exfoliated. A Ti3C2Tx nanosheet colloidal solution was obtained by centrifugation, and a single-layer two-dimensional transition metal carbide MXene was obtained after freeze-drying. 2) Dissolve chitosan in glacial acetic acid and add the MXene obtained in step 1) in a mass ratio of MXene to chitosan of 1:30 to 1:
120. Stir and transfer the solution to a sub-zero refrigerator for freezing, followed by freeze-drying to obtain a MXene / CS aerogel.
2. The method for preparing a MXene / CS aerogel according to claim 1, characterized in that: The mass ratio of LiF and Ti3AlC2 in step 1) is 1:
1.
3. The method for preparing a MXene / CS aerogel according to claim 1, characterized in that: The stirring in step 1) is carried out for 24 to 26 hours, and the temperature is controlled at 30 to 35°C.
4. The method for preparing a MXene / CS aerogel according to claim 1, wherein: The mass ratios of MXene and chitosan in step 2) were 1:30 and 1:
120.
5. The method for preparing a MXene / CS aerogel according to claim 1, wherein: The viscosity of the chitosan in step 2) is >400 mPa.s.
6. The method for preparing a MXene / CS aerogel according to claim 1, characterized in that: The stirring time in step 2) is 24 to 30 hours.
7. The method for preparing a MXene / CS aerogel according to claim 1, wherein: The refrigerator temperature in step 2) is -70 to -80°C.
8. The method for preparing a MXene / CS aerogel according to claim 1, characterized in that: The freezing time in step 2) is 12 to 20 hours.
Citation Information
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