Preparation method of covalent organic framework reinforced hydrogel material

Abstract

The invention relates to a preparation method of a covalent organic framework reinforced hydrogel material, and belongs to the technical field of hydrogel material preparation. Comprising the following steps: (1) adding an aldehyde monomer into an organic solvent to obtain a phase A; (2) dispersing an amino monomer in a solvent to obtain a phase B; (3) continuously adding a high-molecular polymer into the phase B to obtain a phase C; and (4) adding the phase A into the phase C, and stirring for reaction to obtain the covalent organic framework reinforced hydrogel. The preparation method comprises the following steps: physically mixing an amino monomer and a high-molecular polymer, reacting an aldehyde monomer with the amino monomer in the mixed product, and carrying out one-step in-situ synthesis to obtain the covalent organic framework reinforced hydrogel material, so that the preparation method has the characteristics of simplicity and rapidness in operation, high synthesis efficiency, controllable process and low cost; the problems that the efficiency of traditional COF enhanced high-molecular polymer is low and non-free radical polymerized high-molecular hydrogel cannot be enhanced are solved.

Description

Technical Field

[0001] The invention relates to a method for preparing a covalent organic framework-reinforced hydrogel material, and belongs to the technical field of hydrogel material preparation. Background Art

[0002] Due to its softness and high water content, hydrogels play an important role in many fields such as biomedical engineering, soft robotics, and environmental research. However, the poor mechanical properties of traditional hydrogels greatly limit their applications, so a variety of methods to enhance the mechanical properties of hydrogels have been proposed. Among them, confinement enhancement of hydrogels is an effective improvement strategy, which usually improves the performance of polymer materials by introducing a ring structure. In this mechanism, the ring-penetrating polymer acts as a confinement agent to enhance the mechanical properties of the polymer.

[0003] Covalent organic frameworks (COFs), as a type of ring-shaped porous structure, are widely used in photocatalysis, therapy, surface adsorption, and secondary batteries. However, simply mixing COFs with polymers to achieve a ring-shaped structure to enhance the mechanical properties of hydrogels is usually inefficient.

[0004] At present, there are four main methods for using covalent organic frameworks (COFs) to enhance polymer hydrogels: in situ synthesis of COF and polymers, in situ synthesis of COF and in situ polymerized polymers, COF and polymers, and COF and in situ polymerized polymers. However, due to the harsh conditions for COF synthesis, these four methods usually can only use a combination of COF and polymers, or COF and simple free radical polymerization polymers to enhance hydrogels. However, the former method is less efficient, and the latter method is because most polymers cannot be completed by simple free radical polymerization. In addition, the high temperature and high pressure conditions required for COF also make this strategy to enhance the mechanical properties of hydrogels difficult to achieve. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for preparing a covalent organic framework-enhanced hydrogel material. The method realizes in-situ COF synthesis and the combination of cyclic polymers through a dynamic fluid interface, so that those polymer hydrogels that cannot be polymerized by simple free radicals can also enhance their mechanical properties through COF, which has practical applicability.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a covalent organic framework-enhanced hydrogel material comprises the following steps:

[0008] (1) adding an aldehyde monomer to an organic solvent and mixing them uniformly to obtain a phase A;

[0009] (2) dispersing the amino monomer in a solvent to obtain phase B;

[0010] (3) Continue to add high molecular polymer to phase B and mix well to obtain phase C;

[0011] (4) Add phase A to phase C, stir the reaction at 50-300 r / min for 6-72 h, let stand to separate the layers, freeze-thaw and dry the upper layer solution to obtain a covalent organic framework-reinforced hydrogel.

[0012] Preferably according to the present invention, in step (1), the aldehyde monomer is one or more of trimesaldehyde, 2-hydroxy-1,3,5-trisaldehyde, 2,4-dihydroxy-1,3,5-trisaldehyde, and 2,4,6-trihydroxy-1,3,5-trisaldehyde.

[0013] Preferably according to the present invention, in step (1), the organic solvent is dichloromethane, chloroform or carbon tetrachloride.

[0014] Preferably according to the present invention, in step (1), the molar mass volume ratio of the aldehyde monomer and the organic solvent is (0.01-0.2):(50-500), unit: mmol / mL.

[0015] Preferably according to the present invention, in step (2), the amino monomer is one or more of 5,5'-diamino-2,2'-bipyridine, p-phenylenediamine, 2,5-diaminopyridine, 2,6-diaminopyridine, oxalic acid hydrazide, melamine, 3,5-diaminobenzoic acid, p-diaminoazobenzene, benzidine, 2,5-diaminopyrimidine, pyrazine-2.5-diamine, and [3.3'-bipyridine]-6,6'-diamine.

[0016] Preferably according to the present invention, in step (2), the solvent is water, ethanol, dichloromethane, N-methylpyrrolidone, acetonitrile, methanol, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, ether, cyclohexane, toluene or benzene.

[0017] Preferably according to the present invention, in step (2), the molar mass volume ratio of the amino monomer and the solvent is (0.015-0.3):(50-500), unit: mmol / mL.

[0018] Preferably according to the present invention, in step (3), the high molecular weight polymer is one or more of polyethylene glycol, polyvinyl alcohol, sodium alginate, chitosan, and agar.

[0019] Preferably according to the present invention, in step (3), the mass volume ratio of the high molecular weight polymer to phase B is (3-10):100, unit: g / mL.

[0020] Preferably according to the present invention, in step (4), the volume ratio of phase A to phase C is 1:1.

[0021] Preferably, according to the present invention, in step (4), the stirring reaction is carried out at 100 to 200 r / min for 12 to 36 hours.

[0022] The present invention also provides a covalent organic framework reinforced hydrogel material prepared according to the preparation method.

[0023] Preferably according to the present invention, the mass percentage of the covalent organic framework in the covalent organic framework-enhanced hydrogel material is 0.001% to 1%.

[0024] The technical features and beneficial effects of the present invention are as follows:

[0025] 1. Different from the conventional method of first synthesizing an in-situ covalent organic framework (COF) and then preparing a gel by in-situ synthesizing a polymer to perforate the COF, the present invention first physically mixes the amino monomer and the high molecular weight polymer, then reacts the aldehyde monomer with the amino monomer in the mixed product, and obtains the covalent organic framework-enhanced hydrogel material by a one-step in-situ synthesis. The method has the characteristics of simple and fast operation, high synthesis efficiency, controllable process and low cost, and solves the problems of low efficiency of traditional COF-enhanced high molecular weight polymer and inability to enhance non-radical polymerization high molecular weight hydrogel.

[0026] 2. The mass percentage of the covalent organic framework in the covalent organic framework-enhanced hydrogel material of the present invention is 0.001% to 1%, wherein the COF component interacts with the high molecular polymer, has strong mechanical properties, and has good tensile properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the XRD pattern of the product prepared in Example 2.

[0028] Figure 2 The DSC graphs of the products prepared in Example 3 and Comparative Examples 1 and 2 are shown.

[0029] Figure 3 The tensile diagrams of the products prepared in Example 2 and Comparative Example 1 are shown. DETAILED DESCRIPTION

[0030] The present invention is further described below by specific examples and accompanying drawings, but the scope of the present invention is not limited. It should be noted that the following detailed descriptions are exemplary and are intended to provide further description of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments of the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] The raw materials used in the examples are all conventional raw materials, and the equipment used are all conventional equipment, which can be purchased from commercial sources.

[0033] Example 1

[0034] A method for preparing a covalent organic framework-enhanced hydrogel material comprises the following steps:

[0035] (1) Add 0.01 mmol of 2,4,6-triformylphloroglucinol to 100 mL of dichloromethane and mix well to obtain phase A;

[0036] (2) 0.015 mmol of 2,5-diaminopyridine was ultrasonically dispersed in 100 mL of water to obtain phase B;

[0037] (3) Add 10 g of polyvinyl alcohol to phase B and mix well to obtain phase C;

[0038] (4) 100 mL of phase A was added to 100 mL of phase C, and the reaction was stirred at 100 r / min for 24 h. The upper layer solution was frozen and thawed, and the freeze-thaw cycle was repeated three times. After drying, a covalent organic framework-enhanced hydrogel was obtained.

[0039] The mass percentage of the covalent organic framework in the covalent organic framework-reinforced hydrogel material prepared in this example is 0.05%.

[0040] Example 2

[0041] A method for preparing a covalent organic framework-enhanced hydrogel material comprises the following steps:

[0042] (1) Add 0.2 mmol of 2,4,6-triformylphloroglucinol to 100 mL of dichloromethane and mix well to obtain phase A;

[0043] (2) 0.3 mmol of p-phenylenediamine was ultrasonically dispersed in 100 mL of water to obtain phase B;

[0044] (3) Add 3 g of polyvinyl alcohol to phase B and mix well to obtain phase C;

[0045] (4) Add 100 mL of phase A to 100 mL of phase C, stir the reaction at 130 r / min for 36 h, let stand to separate the layers, freeze and thaw the upper layer solution, and repeat the freeze-thaw process three times. After drying, a covalent organic framework-enhanced hydrogel (TpPa+PVA) was obtained.

[0046] The mass percentage of the covalent organic framework in the covalent organic framework-reinforced hydrogel material prepared in this example is 0.03%.

[0047] The XRD pattern of the covalent organic framework-enhanced hydrogel prepared in this example is shown in FIG. Figure 1 shown.

[0048] Depend on Figure 1 It can be seen that the covalent organic framework-enhanced hydrogel prepared in this example contains COF components, COF is successfully synthesized, and the display peak of polyvinyl alcohol can be seen.

[0049] Example 3

[0050] A method for preparing a covalent organic framework-enhanced hydrogel material comprises the following steps:

[0051] (1) Add 0.1 mmol of 2,4,6-triformylphloroglucinol to 100 mL of dichloromethane and mix well to obtain phase A;

[0052] (2) 0.15 mmol of 2,5-diaminopyridine was ultrasonically dispersed in 100 mL of water to obtain phase B;

[0053] (3) Continue to add 5 g of polyvinyl alcohol to phase B and mix well to obtain phase C;

[0054] (4) 100 mL of phase A was added to 100 mL of phase C, and the reaction was stirred at 50 r / min for 24 h. The upper layer solution was frozen and thawed, and the freeze-thaw cycle was repeated three times. After drying, a covalent organic framework-enhanced hydrogel was obtained.

[0055] The mass percentage of the covalent organic framework in the covalent organic framework-reinforced hydrogel material prepared in this example is 0.01%.

[0056] Example 4

[0057] A method for preparing a covalent organic framework-enhanced hydrogel material comprises the following steps:

[0058] (1) Add 0.02 mmol of 2,4,6-triformylphloroglucinol to 100 mL of dichloromethane and mix well to obtain phase A;

[0059] (2) 0.03 mmol of p-phenylenediamine was ultrasonically dispersed in 100 mL of water to obtain phase B;

[0060] (3) Add 10 g of polyvinyl alcohol to phase B and mix well to obtain phase C;

[0061] (4) 100 mL of phase A was added to 100 mL of phase C, and the reaction was stirred at 100 r / min for 24 h. The upper layer solution was frozen and thawed, and the freeze-thaw cycle was repeated three times. After drying, a covalent organic framework-enhanced hydrogel was obtained.

[0062] The mass percentage of the covalent organic framework in the covalent organic framework-reinforced hydrogel material prepared in this example is 0.1%.

[0063] Example 5

[0064] A method for preparing a covalent organic framework-enhanced hydrogel material comprises the following steps:

[0065] (1) Add 0.1 mmol of 2,4-dihydroxy-1,3,5-benzenetricarboxaldehyde to 100 mL of dichloromethane and mix well to obtain phase A;

[0066] (2) 0.15 mmol of 2,5-diaminopyridine was ultrasonically dispersed in 100 mL of water to obtain phase B;

[0067] (3) Continue to add 10 g of sodium alginate to phase B and mix well to obtain phase C;

[0068] (4) 100 mL of phase A was added to 100 mL of phase C, and the reaction was stirred at 100 r / min for 24 h. The upper layer solution was frozen and thawed, and the freeze-thaw cycle was repeated three times. After drying, a covalent organic framework-enhanced hydrogel was obtained.

[0069] The mass percentage of the covalent organic framework in the covalent organic framework-reinforced hydrogel material prepared in this example is 0.25%.

[0070] Example 6

[0071] A method for preparing a covalent organic framework-enhanced hydrogel material comprises the following steps:

[0072] (1) Add 0.1 mmol of 2,4-dihydroxy-1,3,5-benzenetricarboxaldehyde to 100 mL of dichloromethane and mix well to obtain phase A;

[0073] (2) 0.15 mmol of 5,5'-diamino-2,2'-bipyridine was ultrasonically dispersed in 100 mL of water to obtain phase B;

[0074] (3) Add 10 g of chitosan to phase B and mix well to obtain phase C;

[0075] (4) 100 mL of phase A was added to 100 mL of phase C, and the reaction was stirred at 200 r / min for 12 h. The upper layer solution was frozen and thawed, and the freeze-thaw cycle was repeated three times. After drying, a covalent organic framework-enhanced hydrogel was obtained.

[0076] The mass percentage of the covalent organic framework in the covalent organic framework-reinforced hydrogel material prepared in this example is 0.05%.

[0077] Comparative Example 1

[0078] A polyvinyl alcohol solution with a mass percentage of 10% was prepared, and the solution was repeatedly frozen and thawed three times to obtain a hydrogel (PVA).

[0079] Comparative Example 2

[0080] A covalent organic framework is prepared by the method described in Example 2, and then equal volumes of phase A and phase B are mixed evenly, washed and dried to obtain a covalent organic framework (TpPa).

[0081] Test example

[0082] 1. The covalent organic framework-enhanced hydrogel (TpPa+PVA) prepared in Example 2, the hydrogel (PVA) prepared in Comparative Example 1, and the covalent organic framework (TpPa) prepared in Comparative Example 2 were subjected to DSC thermal analysis using a differential scanning calorimeter. The test results are as follows: Figure 2 shown.

[0083] Depend on Figure 2 It can be seen that there is an interaction between the COF component and polyvinyl alcohol in the covalent organic framework-enhanced hydrogel prepared in this example.

[0084] 2. The covalent organic framework-enhanced hydrogel (TpPa+PVA) prepared in Example 4 and the hydrogel (PVA) prepared in Comparative Example 1 were subjected to tensile performance tests using a universal stretching machine. The test results are shown in FIG. Figure 3 shown.

[0085] Depend on Figure 3 It can be seen that, compared with Comparative Example 1, the present invention significantly enhances the mechanical properties of the hydrogel through COF and has good stretchability.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify or replace the technical solutions of the present invention with equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a covalent organic framework-enhanced hydrogel material, characterized in that: The steps include: (1) adding an aldehyde monomer to an organic solvent and mixing uniformly to obtain a phase A; (2) dispersing the amino monomer in a solvent to obtain phase B; (3) Continue to add high molecular polymer to phase B and mix well to obtain phase C; (4) Add phase A to phase C, stir the reaction at 50 to 300 r / min for 6 to 72 h, let stand to separate the layers, freeze-thaw and dry the upper layer solution to obtain a covalent organic framework-reinforced hydrogel.

2. The preparation method according to claim 1, characterized in that In step (1), the aldehyde monomer is one or more of trimesaldehyde, 2-hydroxy-1,3,5-trisaldehyde, 2,4-dihydroxy-1,3,5-trisaldehyde, and 2,4,6-trihydroxy-1,3,5-trisaldehyde; and the organic solvent is dichloromethane, chloroform or carbon tetrachloride.

3. The preparation method according to claim 1, characterized in that: In step (1), the molar mass volume ratio of the aldehyde monomer to the organic solvent is (0.01-0.2):(50-500), unit: mmol / mL.

4. The preparation method according to claim 1, characterized in that: In step (2), the amino monomer is one or more of 5,5'-diamino-2,2'-bipyridine, p-phenylenediamine, 2,5-diaminopyridine, 2,6-diaminopyridine, oxalic acid hydrazide, melamine, 3,5-diaminobenzoic acid, p-diaminoazobenzene, benzidine, 2,5-diaminopyrimidine, pyrazine-2.5-diamine, [3.3'-bipyridine]-6,6'-diamine; and the solvent is water, ethanol, dichloromethane, N-methylpyrrolidone, acetonitrile, methanol, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, ether, cyclohexane, toluene or benzene.

5. The preparation method according to claim 1, characterized in that: In step (2), the molar mass volume ratio of the amino monomer and the solvent is (0.015-0.3):(50-500), unit: mmol / mL.

6. The preparation method according to claim 1, characterized in that: In step (3), the high molecular polymer is one or more of polyethylene glycol, polyvinyl alcohol, sodium alginate, chitosan, and agar.

7. The preparation method according to claim 1, characterized in that: In step (3), the mass volume ratio of the high molecular weight polymer to phase B is (3-10):100, unit: g / mL.

8. The preparation method according to claim 1, characterized in that: In step (4), the volume ratio of phase A to phase C is 1:1; and the stirring reaction is carried out at 100 to 200 r / min for 12 to 36 hours.

9. A covalent organic framework reinforced hydrogel material, characterized in that: It is prepared according to the preparation method according to any one of claims 1 to 8.

10. The covalent organic framework reinforced hydrogel material according to claim 9, characterized in that: The mass percentage of the covalent organic framework in the covalent organic framework-enhanced hydrogel material is 0.001% to 1%.

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