A method for preparing a covalent organic framework reinforced hydrogel material

Abstract

The application relates to a preparation method of a covalent organic framework reinforced hydrogel material and belongs to the technical field of hydrogel material preparation. The method comprises the following steps: (1) adding an aldehyde group monomer into an organic solvent to obtain phase A; (2) dispersing an amino monomer in a solvent to obtain phase B; (3) continuously adding a high molecular polymer into the phase B to obtain phase C; and (4) adding the phase A into the phase C, stirring and reacting to obtain the covalent organic framework reinforced hydrogel. The amino monomer and the high molecular polymer are physically mixed first, then the aldehyde group monomer and the amino monomer in the mixed product are reacted, and the covalent organic framework reinforced hydrogel material is obtained through one-step in-situ synthesis, so that the method has the characteristics of simple and quick operation, high synthesis efficiency, controllable process and low cost, and solves the problems of low efficiency of traditional COF reinforced high molecular polymers and the problem that the traditional COF cannot reinforce non-free radical polymerization high molecular hydrogels.

Description

Technical Field

[0001] This invention relates to a method for preparing a covalent organic framework-reinforced hydrogel material, belonging to the field of hydrogel material preparation technology. Background Technology

[0002] Hydrogels, due to their softness and high water content, play an important role in various fields such as biomedical engineering, soft robotics, and environmental research. However, the poor mechanical properties of traditional hydrogels greatly limit their applications, leading to the development of various methods to enhance their mechanical properties. Among these, confinement-enhanced hydrogels are an effective improvement strategy, typically achieved by introducing ring-shaped structures to improve the properties of polymer materials. In this mechanism, the ring-shaped polymer acts as a confinement agent, enhancing the polymer's mechanical properties.

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

[0004] Currently, there are four main methods for enhancing polymer hydrogels using covalent organic frameworks (COFs): in-situ synthesis of COFs with polymers, in-situ synthesis of COFs with in-situ polymerized polymers, COFs with polymers, and COFs with in-situ polymerized polymers. However, due to the demanding synthesis conditions of COFs, these four methods typically only utilize combinations of COFs with polymers or COFs with simple free radical polymers to enhance hydrogels. The former method is less efficient, while the latter is problematic because most polymers cannot be synthesized through simple free radical polymerization. Furthermore, the high temperature and pressure requirements of COFs make this strategy for enhancing the mechanical properties of hydrogels difficult to implement. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing covalent organic framework-reinforced hydrogel materials. This method achieves in-situ COF synthesis and the binding of ring-penetrating polymers through a dynamic fluid interface, thereby enabling the enhancement of the mechanical properties of polymeric hydrogels that cannot be polymerized through simple free radical polymerization, thus possessing practical applications.

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

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

[0008] (1) Add aldehyde monomer to organic solvent and mix well to obtain phase A;

[0009] (2) The amino monomer is dispersed in a solvent to obtain phase B;

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

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

[0012] According to a preferred embodiment of the present invention, in step (1), the aldehyde monomer is one or more of the following: pyromellitic methyl ether, 2-hydroxy-1,3,5-pyromellitic methyl ether, 2,4-dihydroxy-1,3,5-pyromellitic methyl ether, and 2,4,6-trihydroxy-1,3,5-pyromellitic methyl ether.

[0013] According to a preferred embodiment of the present invention, in step (1), the organic solvent is dichloromethane, trichloromethane, or carbon tetrachloride.

[0014] According to a preferred embodiment of 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] According to a preferred embodiment of the present invention, in step (2), the amino monomer is one or more of the following: 5,5'-diamino-2,2'-bipyridine, p-phenylenediamine, 2,5-diaminopyridine, 2,6-diaminopyridine, oxalohydrazide, melamine, 3,5-diaminobenzoic acid, p-diaminoazobenzene, benzidine, 2,5-diaminopyrimidine, pyrazine-2,5-diamine, and [3,3'-bipyridine]-6,6'-diamine.

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

[0017] According to a preferred embodiment of 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] According to a preferred embodiment of the present invention, in step (3), the polymer is one or more of polyethylene glycol, polyvinyl alcohol, sodium alginate, chitosan, and agar.

[0019] According to a preferred embodiment of the present invention, in step (3), the mass-to-volume ratio of the polymer and phase B is (3-10):100, unit: g / mL.

[0020] According to a preferred embodiment of the present invention, in step (4), the volume ratio of phase A to phase C is 1:1.

[0021] According to a preferred embodiment of the present invention, in step (4), the stirring reaction is carried out at 100-200 r / min for 12-36 h.

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

[0023] According to a preferred embodiment of the present invention, the mass percentage of the covalent organic framework in the covalent organic framework-reinforced hydrogel material is 0.001% to 1%.

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

[0025] 1. Unlike the traditional method of first synthesizing covalent organic frameworks (COFs) in situ and then preparing gels by in situ synthesis of polymer-perforated COFs, this invention first physically mixes amino monomers and polymers, then reacts aldehyde monomers with amino monomers in the mixture to obtain covalent organic framework-reinforced hydrogel materials in one step in situ. This method features simple and fast operation, high synthesis efficiency, controllable process, and low cost, solving the problems of low efficiency in reinforcing polymers with traditional COFs and the inability to reinforce non-radical polymer hydrogels.

[0026] 2. The covalent organic framework reinforced hydrogel material of the present invention has a covalent organic framework mass percentage of 0.001% to 1%, and the COF component therein interacts with the polymer, resulting in strong mechanical properties and good tensile properties. Attached Figure Description

[0027] Figure 1 The image shows the XRD pattern of the product prepared in Example 2.

[0028] Figure 2 The images show the DSC diagrams of the products prepared in Example 3 and Comparative Examples 1 and 2.

[0029] Figure 3 The images show tensile diagrams of the products prepared in Example 2 and Comparative Example 1. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments and accompanying drawings, but this is not intended to limit the scope of protection of the present invention. It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

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

[0032] All raw materials and equipment used in the examples are conventional and can be purchased commercially.

[0033] Example 1

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

[0035] (1) Add 0.01 mmol of 2,4,6-tricarboxymethyl phloroglucinol to 100 mL of dichloromethane, mix well, and 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) Continue to add 10g of polyvinyl alcohol to phase B, mix well, and obtain phase C;

[0038] (4) Add 100 mL of phase A to 100 mL of phase C, stir at 100 r / min for 24 h, let stand to separate into layers, freeze and thaw the upper layer solution, repeat the freeze-thaw cycle three times, and dry to obtain a covalent organic framework reinforced hydrogel.

[0039] In this embodiment, the covalent organic framework-reinforced hydrogel material has a covalent organic framework mass percentage of 0.05%.

[0040] Example 2

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

[0042] (1) Add 0.2 mmol of 2,4,6-tricarboxymethyl phloroglucinol to 100 mL of dichloromethane, mix well, and 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) Continue to add 3g of polyvinyl alcohol to phase B, mix well, and obtain phase C;

[0045] (4) Add 100 mL of phase A to 100 mL of phase C, stir at 130 r / min for 36 h, let stand to separate into layers, freeze and thaw the upper layer solution, repeat the freeze-thaw cycle three times, and dry to obtain covalent organic framework reinforced hydrogel (TpPa+PVA).

[0046] In this embodiment, the covalent organic framework in the prepared covalent organic framework-reinforced hydrogel material has a mass percentage of 0.03%.

[0047] The XRD pattern of the covalent organic framework-reinforced hydrogel prepared in this embodiment is shown in the figure below. Figure 1 As shown.

[0048] Depend on Figure 1 It can be seen that the covalent organic framework reinforced hydrogel prepared in this embodiment contains COF, the COF was successfully synthesized, and the peak of polyvinyl alcohol can be observed.

[0049] Example 3

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

[0051] (1) Add 0.1 mmol of 2,4,6-tricarboxymethyl phloroglucinol to 100 mL of dichloromethane, mix well, and 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 5g of polyvinyl alcohol to phase B, mix well, and obtain phase C;

[0054] (4) Add 100 mL of phase A to 100 mL of phase C, stir at 50 r / min for 24 h, let stand to separate into layers, freeze and thaw the upper layer solution, repeat the freeze-thaw cycle three times, and dry to obtain a covalent organic framework reinforced hydrogel.

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

[0056] Example 4

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

[0058] (1) Add 0.02 mmol of 2,4,6-tricarboxymethyl phloroglucinol to 100 mL of dichloromethane, mix well, and 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) Continue to add 10g of polyvinyl alcohol to phase B, mix well, and obtain phase C;

[0061] (4) Add 100 mL of phase A to 100 mL of phase C, stir at 100 r / min for 24 h, let stand to separate into layers, freeze and thaw the upper layer solution, repeat the freeze-thaw cycle three times, and dry to obtain a covalent organic framework reinforced hydrogel.

[0062] In this embodiment, the covalent organic framework-reinforced hydrogel material has a covalent organic framework mass percentage of 0.1%.

[0063] Example 5

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

[0065] (1) Add 0.1 mmol of 2,4-dihydroxy-1,3,5-pyromellitic aldehyde to 100 mL of dichloromethane, mix well, and 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 10g of sodium alginate to phase B, mix well, and obtain phase C;

[0068] (4) Add 100 mL of phase A to 100 mL of phase C, stir at 100 r / min for 24 h, let stand to separate into layers, freeze and thaw the upper layer solution, repeat the freeze-thaw cycle three times, and dry to obtain a covalent organic framework reinforced hydrogel.

[0069] In this embodiment, the covalent organic framework-reinforced hydrogel material has a covalent organic framework mass percentage of 0.25%.

[0070] Example 6

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

[0072] (1) Add 0.1 mmol of 2,4-dihydroxy-1,3,5-pyromellitic aldehyde to 100 mL of dichloromethane, mix well, and 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) Continue to add 10g of chitosan to phase B, mix well, and obtain phase C;

[0075] (4) Add 100 mL of phase A to 100 mL of phase C, stir at 200 r / min for 12 h, let stand to separate into layers, freeze and thaw the upper layer solution, repeat the freeze-thaw cycle three times, and dry to obtain a covalent organic framework reinforced hydrogel.

[0076] In this embodiment, the covalent organic framework-reinforced hydrogel material has a covalent organic framework mass percentage of 0.05%.

[0077] Comparative Example 1

[0078] A 10% polyvinyl alcohol solution was prepared and subjected to three freeze-thaw cycles to obtain a hydrogel (PVA).

[0079] Comparative Example 2

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

[0081] Test case

[0082] 1. Differential scanning calorimetry (DSC) was used to perform thermal analysis on the covalent organic framework-reinforced 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. The test results are as follows: Figure 2 As shown.

[0083] Depend on Figure 2 It can be seen that the COF component in the covalent organic framework reinforced hydrogel prepared in this embodiment interacts with polyvinyl alcohol.

[0084] 2. The tensile properties of the covalent organic framework-reinforced hydrogel (TpPa+PVA) prepared in Example 4 and the hydrogel (PVA) prepared in Comparative Example 1 were tested using a universal tensile testing machine. The test results are as follows: Figure 3 As shown.

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

[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 foregoing embodiments, those skilled in the art can still modify or make equivalent substitutions to the technical solutions of the present invention 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-reinforced hydrogel material, characterized in that, The steps include the following: (1) Add aldehyde monomer to organic solvent and mix well to obtain phase A; Wherein, the aldehyde monomer is one or more selected from pyromellitic aldehyde, 2-hydroxy-1,3,5-pyromellitic aldehyde, 2,4-dihydroxy-1,3,5-pyromellitic aldehyde, and 2,4,6-trihydroxy-1,3,5-pyromellitic aldehyde; the organic solvent is dichloromethane, trichloromethane, or carbon tetrachloride; the molar mass-volume ratio of the aldehyde monomer to the organic solvent is (0.01~0.2):(50~500), unit: mmol / mL; (2) The amino monomer is dispersed in a solvent to obtain phase B; The amino monomer is one or more selected from 5,5'-diamino-2,2'-bipyridine, p-phenylenediamine, 2,5-diaminopyridine, 2,6-diaminopyridine, oxalohydrazide, melamine, 3,5-diaminobenzoic acid, p-diaminoazobenzene, benzidine, 2,5-diaminopyrimidine, pyrazine-2,5-diamine, and [3,3'-bipyridine]-6,6'-diamine; the solvent is water, ethanol, dichloromethane, N-methylpyrrolidone, acetonitrile, methanol, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, diethyl ether, cyclohexane, toluene, or benzene; the molar mass-volume ratio of the amino monomer to the solvent is (0.015~0.3):(50~500), unit: mmol / mL; (3) Continue to add polymer to phase B and mix evenly to obtain phase C; The polymer is one or more of polyethylene glycol, polyvinyl alcohol, sodium alginate, chitosan, and agar; the mass-to-volume ratio of the polymer to phase B is (3~10):100, unit: g / mL; (4) Add phase A to phase C and stir at 50~300 r / min for 6~72h. Let stand and separate into layers. After freeze-thaw drying of the upper layer solution, a covalent organic framework reinforced hydrogel is obtained.

2. 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; the stirring reaction is carried out at 100~200 r / min for 12~36h.

3. A covalent organic framework-reinforced hydrogel material, characterized in that, It is prepared according to the preparation method described in any one of claims 1 to 2.

4. The covalent organic framework-reinforced hydrogel material as described in claim 3, characterized in that, The covalent organic framework in the covalent organic framework-reinforced hydrogel material has a mass percentage of 0.001% to 1%.

Images