Preparation method and application of temperature response type UiO-66-NH2 composite hydrogel

Abstract

The invention relates to a preparation method and application of temperature-responsive UiO-66-NH2 composite hydrogel, and belongs to the technical field of polymer composites.UiO-66-NH2 is used as a metal organic framework, N-isopropylacrylamide is used as a temperature-sensitive polymer, and acrylamide is additionally added to construct a double-interpenetrating cross-linked network, so that the temperature-responsive UiO-66-NH2 composite hydrogel is prepared. In an aqueous solution environment, 2-carboxyl-2-methyl-1-phenyl-1-acetone is used as a photoinitiator, N, N '-methylene bisacrylamide is used as a cross-linking agent, and a reaction is performed to obtain the temperature-responsive UiO-66-NH2 composite hydrogel. The method is simple to operate and simple in reaction condition, and the temperature response type UiO-66-NH2 composite hydrogel can be synthesized by stirring and fusing at normal temperature and then photo-initiation. The prepared composite hydrogel is adjustable in shape, has relatively good flexibility and temperature-responsive water adsorption and release capability, and is relatively excellent in water adsorption performance.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a temperature-responsive UiO-66-NH2 composite hydrogel. Background Art Hydrogel is a new type of functional polymer material with a three-dimensional network structure. It has adjustable physical and chemical properties. Since it contains a large number of hydrophilic groups such as carboxyl and hydroxyl groups and has a good pore structure, the hydrogel material shows great advantages in water absorption, water retention and adsorption. In addition, the synthesis of hydrogel is also relatively simple. Water-soluble polymers can form hydrogels after chemical or physical crosslinking. The composition and structural form of hydrogel materials can be adjusted by adjusting the synthetic materials and functional groups to obtain various functionalized hydrogels.

[0002] Metal-organic framework (MOF) materials have excellent properties such as high porosity, adjustable structure and ultra-large specific surface area, and have broad application prospects in many fields. However, some shortcomings of MOFs materials limit their further development. For example, the chemical stability of some MOFs materials is poor, and the prepared MOFs are usually solid powders, which makes them easy to agglomerate and reduce their activity. Combining MOFs materials with other functional materials to construct composite materials can effectively solve this problem, and can also produce new properties that a single material does not have through the synergistic effect between the two materials.

[0003] Therefore, the idea of ​​combining MOFs with hydrogels has attracted widespread attention from researchers. MOFs particles have effective sites for binding hydrophilic molecules and can bind to hydrogels during the entire hydrogel-gel transition process, enhancing the mechanical properties of hydrogels while effectively avoiding the shortcomings of MOFs.

[0004] Temperature-responsive hydrogel is a smart hydrogel that can keenly sense external temperature fluctuations and respond to them. It has broad application prospects in smart windows, biomedicine, and fluid switches. N-isopropylacrylamide (NIPAM) is one of the most widely studied temperature-responsive hydrogels. Its lower critical solution temperature (LCST) is about 32°C, and there are both hydrophilic amide groups and hydrophobic isopropyl groups in the molecule. When the temperature is higher than the LCST, the hydrogel is in a contracted state, and when it is lower than the LCST, the hydrogel is in a swollen state. Summary of the invention

[0005] The present invention aims to solve the problems of MOFs composite hydrogel in the prior art, such as cumbersome preparation, difficult reuse, insufficient adsorption capacity, easy collapse, etc. In order to achieve the purpose of multi-faceted application of hydrogel, a preparation method and use of temperature-responsive UiO-66-NH2 composite hydrogel is provided.

[0006] A preparation method and use of a temperature-responsive UiO-66-NH2 composite hydrogel comprises the following steps: 1. Mix zirconium chloride and terephthalic acid in a mass ratio of 1:1.3 in N,N'-dimethylformamide solution, dissolve by ultrasonication, add acetic acid, mix well, transfer the solution to a polytetrafluoroethylene reactor, react at 120°C for 24h, collect the white solid by centrifugal separation of the supernatant, wash with DMF and methanol three times respectively, and finally dry the product in a vacuum drying oven at 60°C overnight to obtain a powdered UiO-66-NH2 nanomaterial; 2. Dissolve N-isopropylacrylamide and acrylamide in 3 mL of deionized water, stir magnetically at room temperature, and after it becomes a clear solution, add the required amount of UiO-66-NH2 powder and mix evenly, then add N,N'-methylenebisacrylamide and stir evenly; 3. Add 6 μL of photoinitiator 1173, stir for 20 min, and after mixing evenly, inject the solution into the PVC plastic mold. Finally, cure in the UV chamber for 60 s. Polymerize to obtain UiO-66-NH2 composite hydrogel.

[0007] In the step 1, the mass ratio of zirconium chloride to terephthalic acid is 1:1.3.

[0008] The method for preparing the UiO-66-NH2 nanomaterial in step 1 is a hydrothermal method.

[0009] The reaction temperature of UiO-66-NH2 nanoparticles in step 2 is 120°C and the reaction time is 24 hours.

[0010] In the step 2, the mass ratio of N-isopropylacrylamide to acrylamide is 9:1.

[0011] The mass ratio of UiO-66-NH2 added in step 2 to the monomer mass is 0:1 to 1:10.

[0012] The photoinitiator 1173 added in step three needs to meet 2 μL / mL.

[0013] In the step 3, the ultraviolet light is initiated for 60 seconds.

[0014] The temperature-responsive UiO-66-NH2 composite hydrogel prepared by the invention is applied to adsorption and drug sustained release.

[0015] Compared with the prior art, the present invention has the following advantages: The invention uses zirconium chloride, terephthalic acid, N-isopropylacrylamide and acrylamide as raw materials to prepare a temperature-responsive hydrogel, which is irradiated for 60 seconds by an ultraviolet curing method and stored at room temperature.

[0016] The invention prepares the temperature-responsive hydrogel by using zirconium chloride, terephthalic acid, N-isopropylacrylamide and acrylamide ultraviolet curing method.

[0017] The reaction conditions of the present invention are simple, the output efficiency is high, and the repeatability is strong. The obtained hydrogel has a rich porous network structure, which greatly improves the attachment sites in the adsorption process while providing a high-capacity water storage space. The polymer network firmly fastens the UiO-66-NH2 nanoparticles, making it more stable in water compared with traditional MOFs, with higher water adsorption and storage performance and relatively convenient recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a real picture of the preparation of UiO-66-NH2 composite hydrogel in specific example 1; wherein a is a blank hydrogel; b is a UiO-66-NH2 composite hydrogel; Figure 2 It is a scanning electron microscope image of the UiO-66-NH2 composite hydrogel prepared in specific example 1; wherein a is the UiO-66-NH2 nanomaterial; b is the blank hydrogel; c is the UiO-66-NH2 composite hydrogel; Figure 3 is a schematic diagram of swelling of UiO-66-NH2 composite hydrogel at different temperatures in the preparation of specific example 1; Figure 4 This is a graph showing the adsorption of different dyes by the UiO-66-NH2 composite hydrogel prepared in specific example 1. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0020] Embodiment 1: A preparation method and use of a temperature-responsive UiO-66-NH2 composite hydrogel comprises the following steps: 1. Mix zirconium chloride and terephthalic acid in a mass ratio of 1:1.3 in N,N'-dimethylformamide solution, dissolve by ultrasonication, add acetic acid, mix well, transfer the solution to a polytetrafluoroethylene reactor, react at 120°C for 24h, collect the white solid by centrifugal separation of the supernatant, wash with DMF and methanol three times respectively, and finally dry the product in a vacuum drying oven at 60°C overnight to obtain a powdered UiO-66-NH2 nanomaterial; 2. Dissolve N-isopropylacrylamide and acrylamide in 3 mL of deionized water, stir magnetically at room temperature, and after it becomes a clear solution, add the required amount of UiO-66-NH2 powder and mix evenly, then add N,N'-methylenebisacrylamide and stir evenly; Third, add 6 μL of photoinitiator 1173, stir for 20 min, mix evenly, inject the solution into the PVC plastic mold, and finally cure in the UV chamber for 60 s. Polymerization to obtain UiO-66-NH2 composite hydrogel.

[0021] Example 1 is a one-pot UV curing method to prepare UiO-66-NH2 composite hydrogel. Its preparation method is simple, low cost, material size is controllable, has sensitive pressure sensing and temperature response capabilities, and has good application in adsorption and sustained release of drugs.

[0022] The actual picture of the UiO-66-NH2 composite hydrogel material prepared in Example 1 is as follows Figure 1 As shown, the temperature-responsive UiO-66-NH2 hydrogel was prepared in one pot by UV curing using cheap and readily available N-isopropylacrylamide, acrylamide, and UiO-66-NH2 nanomaterials.

[0023] The scanning electron microscope image of the UiO-66-NH2 composite hydrogel material prepared in Example 1 is as follows Figure 2 As shown, a large number of UiO-66-NH2 nanoparticles were observed to be attached to the network formed by polymer entanglement, indicating that the hydrogel and UiO-66-NH2 were successfully polymerized.

[0024] The UiO-66-NH2 composite hydrogel material prepared in Example 1 swells at different temperatures. Figure 3 As shown, the hydrogel swells at low temperatures and shrinks at high temperatures.

[0025] The UiO-66-NH2 composite hydrogel prepared in Example 1 adsorbs different dyes, such as Figure 4 As shown in the figure, it can be seen that the UiO-66-NH2 composite hydrogel has the best adsorption effect on Congo red (CR).

Claims

1. A preparation method and use of a temperature-responsive UiO-66-NH2 composite hydrogel, characterized in that The method comprises the following steps: Step 1, Preparation of UiO-66-NH2 Nanoparticles A certain amount of zirconium chloride and terephthalic acid were weighed and dissolved in N,N'-dimethylformamide (DMF), ultrasonically dissolved, acetic acid was added, and mixed evenly. The solution was transferred to a polytetrafluoroethylene reactor and reacted at 120°C for 24 hours. The white solid was collected by centrifugal separation of the supernatant, washed three times with DMF and methanol, and finally the product was dried in a vacuum drying oven at 60°C overnight to obtain powdered UiO-66-NH2 nanomaterials. Step 2, Preparation of UiO-66-NH2 Nanocomposite Hydrogel In this experiment, a one-pot method was used to prepare the composite hydrogel. First, 0.9 g N-isopropylacrylamide (NIPAM) and 0.1 g acrylamide (AAM) were dissolved in 3 mL of deionized water, and magnetically stirred at room temperature. After the solution became clear, the required amount of UiO-66-NH2 powder was added and mixed evenly, and then 0.002 g N, N'-methylenebisacrylamide (MBA) was added. After mixing evenly, 6 μL of 2-carboxy-2-methyl-1-phenyl-1-propanone (1173) photoinitiator was added, stirred for 20 min, and finally cured in a UV chamber for 60 s to polymerize to obtain the temperature-responsive UiO-66-NH2 composite hydrogel.

2. The preparation method and use of a temperature-responsive UiO-66-NH2 nanocomposite hydrogel according to claim 1, characterized in that: The mass ratio of terephthalic acid to zirconium chloride is 1:1.

3.

3. The preparation method and use of a temperature-responsive composite hydrogel according to claim 1, characterized in that: The reaction temperature of the UiO-66-NH2 nanoparticles obtained after the reaction is 120° C. and the reaction time is 24 hours.

4. The preparation method and use of a temperature-responsive UiO-66-NH2 nanocomposite hydrogel according to claim 1, characterized in that: The mass ratio of the UiO-66-NH2 nanomaterial to the monomer is 0:100 to 1:

10.

5. The preparation method and use of a temperature-responsive UiO-66-NH2 nanocomposite hydrogel according to claim 1, characterized in that: 3 mL of eutectic solvent was added.

6. The preparation method and use of a temperature-responsive UiO-66-NH2 nanocomposite hydrogel according to claim 1, characterized in that: The added photoinitiator 1173 needs to meet 2 μL / mL.

7. The preparation method and use of a temperature-responsive UiO-66-NH2 nanocomposite hydrogel according to claim 1, characterized in that: UV light initiation for 60 s.

8. The temperature-responsive UiO-66-NH2 composite hydrogel and its preparation method and use according to claim 1, characterized in that: Used for adsorption and sustained release of drugs.

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