A kind of maleic acid acrylamide copolymer hydrogel and preparation method thereof
By using the combination of deep eutectic solvent and maleic acid in hydrogel preparation, the copolymerization of low-active monomers and high-active monomers is achieved, and the high cost of photo-induced front-end polymerization and self-healing ability in the prior art are solved. The poor problem significantly improves the self-healing efficiency and speed of the hydrogel.
Patent Information
- Application Number
- CN202211481943.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-24
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2042-11-24
AI Technical Summary
In the existing hydrogel preparation methods, photoinduced front-end polymerization requires a high-energy light source, which is costly and poor self-healing ability, which limits the application of hydrogels.
Deep eutectic solvent is used as the reaction solvent to induce heat front polymerization. By adding maleic acid at a temperature not less than 32°C, copolymerization of low-active monomers and high-active monomers is achieved, and carboxyl groups in maleic acid are passed. The reversible hydrogen bond interaction between the group and acrylamide and choline chloride improves the self-healing performance of the hydrogel.
It reduces the preparation cost, improves the self-healing efficiency and speed of hydrogels, significantly improves the success rate of copolymerization of low-active monomers and high-active monomers, and forms a rich reversible hydrogen bond network during the self-healing process. Significantly improves the self-healing performance of the hydrogel.
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Figure CN115894965B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of hydrogel preparation, and in particular to a maleic acid acrylamide copolymer hydrogel and a preparation method thereof. Background Art
[0002] At present, the preparation method of low-activity monomer and high-activity monomer copolymer hydrogel is mainly light-induced front-end polymerization. Light-induced front-end polymerization requires the introduction of high-energy light sources to stimulate the generation of free radicals. In existing reports, most of them use ultraviolet light as the light source, and the reaction device is complex and costly. In addition, the traditional hydrogel has poor self-healing ability, slow speed, and harsh conditions, which limits the application of hydrogel. Summary of the invention
[0003] The present invention provides a maleic acid acrylamide copolymer hydrogel and a preparation method thereof to solve the above technical problems, realizes the copolymerization of low-activity monomers and high-activity monomers, and the hydrogel has self-healing properties.
[0004] The technical solution of the present invention to solve the above technical problems is as follows:
[0005] In one aspect, the present invention provides a method for preparing a maleic acid acrylamide copolymer hydrogel, comprising the following steps:
[0006] S1: mixing a hydrogen bond donor, a hydrogen bond acceptor and a cross-linking agent and stirring at 70-100° C. until a transparent and clear liquid is obtained to obtain a deep eutectic solvent;
[0007] S2: adding an initiator and maleic acid to the deep eutectic solvent at a temperature not lower than 32° C., stirring uniformly to form a mixture solution, transferring the formed mixture solution to a tubular reactor, heating the reactor with a heat source to initiate a polymerization reaction, and then removing the heat source until the mixture solution in the entire reactor is completely converted into a polymer gel;
[0008] S3: After soaking and washing the polymer gel, freeze-drying is performed to obtain maleic acid acrylamide copolymer hydrogel.
[0009] Furthermore, the hydrogen bond donor is acrylamide.
[0010] Furthermore, the hydrogen bond acceptor is choline chloride.
[0011] Furthermore, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:2-3.
[0012] Furthermore, the amount of maleic acid used is 2.34-9.37% of the total mass of the deep eutectic solvent.
[0013] Furthermore, the cross-linking agent is N-methylenebisacrylamide.
[0014] Furthermore, the amount of the cross-linking agent is 0.5-1% of the total mass of the deep eutectic solvent.
[0015] Furthermore, the initiator is potassium persulfate.
[0016] Furthermore, the amount of the initiator used is 0.25-0.5% of the total mass of the deep eutectic solvent.
[0017] On the other hand, the present invention also provides maleic acid acrylamide copolymer hydrogel prepared by the above preparation method.
[0018] The beneficial effects of the present invention are:
[0019] The present invention adds maleic acid to a deep eutectic solvent and successfully realizes copolymerization of a low-activity monomer and a high-activity monomer through front-end polymerization. The preparation method of front-end polymerization reduces costs, and a deep eutectic solvent is used as a reaction solvent for initiating thermal front-end polymerization during the process. The reaction process is environmentally friendly, the preparation speed is fast, and the success rate of copolymerization of a low-activity monomer and a high-activity monomer is greatly improved.
[0020] The addition of maleic acid introduced carboxyl groups. During the self-healing process of the hydrogel, reversible hydrogen bonding interactions were formed between the carboxyl groups of maleic acid and the amide groups of acrylamide and choline chloride, leading to the improvement of the self-healing properties of the hydrogel. Moreover, with the increase of the maleic acid content, the self-healing efficiency of the hydrogel increased significantly. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 The self-healing rates of the maleic acid acrylamide copolymer hydrogels prepared in Examples 1-4 of the present invention after 0.5 h, 12 h, 24 h and 48 h;
[0022] Figure 2 The stress-strain curves of the maleic acid acrylamide copolymer hydrogel prepared in Example 4 of the present invention after 0.5 h, 12 h, 24 h and 48 h. DETAILED DESCRIPTION
[0023] The principles and features of the present invention are described below in conjunction with the accompanying drawings and specific embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.
[0024] The present invention provides a method for preparing a maleic acid acrylamide copolymer hydrogel, comprising the following steps:
[0025] S1: Mix the hydrogen bond donor, hydrogen bond acceptor and cross-linking agent and stir at 70-100°C until a transparent and clear liquid is obtained to obtain a deep eutectic solvent, and then use the room temperature deep eutectic solvent as a monomer and medium for front-end polymerization to synthesize a filling hydrogel. The selected drugs are all solid and can be uniformly polymerized without other liquid solvents for dissolution;
[0026] S2: adding an initiator and maleic acid to the deep eutectic solvent at a temperature not lower than 32° C., stirring evenly to form a mixture solution, transferring the formed mixture solution to a tubular reactor, heating the reactor with a heat source to initiate a polymerization reaction, and then removing the heat source until the mixture solution in the entire reactor is completely converted into a polymer gel. The addition of maleic acid introduces a carboxyl group. During the self-healing process of the hydrogel, a reversible hydrogen bond interaction is formed between the carboxyl group of the maleic acid and the amide group of acrylamide and choline chloride, resulting in an improvement in the self-healing performance of the hydrogel, and with the increase in the content of maleic acid, the self-healing efficiency of the hydrogel is significantly increased;
[0027] S3: After soaking and washing the polymer gel, freeze-drying is performed to obtain maleic acid acrylamide copolymer hydrogel.
[0028] Preferably, the hydrogen bond donor is acrylamide.
[0029] Preferably, the hydrogen bond acceptor is choline chloride.
[0030] Preferably, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:2-3.
[0031] Preferably, the amount of maleic acid used is 2.34-9.37% of the total mass of the deep eutectic solvent.
[0032] Preferably, the cross-linking agent is N-methylenebisacrylamide.
[0033] Preferably, the amount of the cross-linking agent used is 0.5-1% of the total mass of the deep eutectic solvent.
[0034] Preferably, the initiator is potassium persulfate.
[0035] Preferably, the amount of the initiator used is 0.25-0.5% of the total mass of the deep eutectic solvent.
[0036] On the other hand, the present invention also provides maleic acid acrylamide copolymer hydrogel prepared by the above preparation method.
[0037] The following is a specific implementation method
[0038] Embodiment 1 (FP1)
[0039] (1) 4.264 g of acrylamide, 4.189 g of choline chloride, and 0.090 g of N,N-methylenebisacrylamide were mixed and stirred in an oil bath at 70° C. until a transparent and clear liquid was formed, and then allowed to stand and cool to room temperature to obtain a room temperature deep eutectic solvent liquid;
[0040] (2) adding 0.045 g potassium persulfate and 0.2 g maleic acid to the room temperature deep eutectic solvent liquid obtained in step (1) in sequence to form a mixture solution, and then transferring the formed mixture solution into a test tube, heating the upper end of the reactor with an electric soldering iron to decompose the initiator by heat to initiate the reaction. After the thermal initiation reaction begins, the heat source is removed until all the raw materials in the reactor are converted into polymer gel;
[0041] (3) The polymer gel obtained in step (2) is soaked and washed with distilled water to remove choline chloride, and the polymer gel after soaking and washing is then freeze-dried to obtain the target maleic acid acrylamide copolymer hydrogel, wherein the hydrogel appears white.
[0042] Embodiment 2 (FP2)
[0043] (1) 4.264 g of acrylamide, 4.189 g of choline chloride, and 0.090 g of N,N-methylenebisacrylamide were mixed and stirred in an oil bath at 70° C. until a transparent and clear liquid was formed, and then allowed to stand and cool to room temperature to obtain a room temperature deep eutectic solvent liquid;
[0044] (2) adding 0.045 g potassium persulfate and 0.4 g maleic acid to the room temperature deep eutectic solvent liquid obtained in step (1) in sequence to form a mixture solution, and then transferring the formed mixture solution into a test tube, heating the upper end of the reactor with an electric soldering iron to decompose the initiator by heat to initiate the reaction, and after the thermal initiation reaction begins, removing the heat source until all the raw materials in the reactor are converted into polymer gel;
[0045] (3) The polymer gel obtained in step (2) is soaked and washed with distilled water to remove choline chloride, and the polymer gel after soaking and washing is then freeze-dried to obtain the target maleic acid acrylamide copolymer hydrogel, wherein the hydrogel appears white.
[0046] Embodiment 3 (FP3)
[0047] (1) 4.264 g of acrylamide, 4.189 g of choline chloride, and 0.090 g of N,N-methylenebisacrylamide were mixed and stirred in an oil bath at 70° C. until a transparent and clear liquid was formed, and then allowed to stand and cool to room temperature to obtain a room temperature deep eutectic solvent liquid;
[0048] (2) adding 0.025 g potassium persulfate and 0.6 g maleic acid to the room temperature deep eutectic solvent liquid obtained in step (1) in sequence to form a mixture solution, and then transferring the formed mixture solution into a test tube, heating the upper end of the reactor with an electric soldering iron to decompose the initiator by heat to initiate the reaction, and after the thermal initiation reaction begins, removing the heat source until all the raw materials in the reactor are converted into polymer gel;
[0049] (3) The polymer gel obtained in step (2) is soaked and washed with distilled water to remove choline chloride, and the polymer gel after soaking and washing is then freeze-dried to obtain the target maleic acid acrylamide copolymer hydrogel, wherein the hydrogel appears white.
[0050] Embodiment 4 (FP4)
[0051] (1) 4.264 g of acrylamide, 4.189 g of choline chloride, and 0.090 g of N,N-methylenebisacrylamide were mixed and stirred in an oil bath at 70° C. until a transparent and clear liquid was formed, and then allowed to stand and cool to room temperature to obtain a room temperature deep eutectic solvent liquid;
[0052] (2) adding 0.025 g potassium persulfate and 0.8 g maleic acid to the room temperature deep eutectic solvent liquid obtained in step (1) in sequence to form a mixture solution, and then transferring the formed mixture solution into a test tube, heating the upper end of the reactor with an electric soldering iron to decompose the initiator by heat to initiate the reaction, and after the thermal initiation reaction begins, removing the heat source until all the raw materials in the reactor are converted into polymer gel;
[0053] (3) The polymer gel obtained in step (2) is soaked and washed with distilled water to remove choline chloride, and the polymer gel after soaking and washing is then freeze-dried to obtain the target maleic acid acrylamide copolymer hydrogel, wherein the hydrogel appears white.
[0054] Comparative Example
[0055] 1) 4.264 g acrylamide, 4.189 g choline chloride and 0.085 g N,N-methylenebisacrylamide were mixed and stirred in an oil bath at 70° C. until a transparent and clear liquid was formed, and then allowed to stand and cool to room temperature to obtain a room temperature deep eutectic solvent liquid;
[0056] (2) adding 0.042 g of potassium persulfate to the room temperature deep eutectic solvent liquid obtained in step (1) to form a mixture solution, then transferring the formed mixture solution into a test tube, heating the upper end of the reactor with an electric soldering iron to decompose the initiator by heat to initiate the reaction, and removing the heat source after the thermal initiation reaction begins until all the raw materials in the reactor are converted into polymer gel;
[0057] (3) The polymer gel obtained in step (2) is soaked and washed with distilled water to remove choline chloride, and the polymer gel after soaking and washing is then freeze-dried to obtain a hydrogel, wherein the hydrogel appears transparent.
[0058] The self-healing properties of the maleic acid acrylamide copolymer hydrogels prepared in Examples 1-4 and the hydrogels prepared in the comparative example were tested, and the test method was as follows:
[0059] The columnar hydrogel was cut into two parts and kept in close contact for 30 min without any external stimulation to obtain a recombined sample. Then, the mechanical properties of the repaired sample were measured again to evaluate the self-healing performance of the gel. Each measurement was repeated multiple times and the average was taken for plotting. The self-healing rate is:
[0060]
[0061] Among them, P1 is the tensile strength of the repaired hydrogel, and P2 is the tensile strength of the original hydrogel.
[0062] The test results are as follows Figure 1 The specific data are as follows:
[0063] 0.5h 12h 24h 48h Example 1 14.67 37.3 44.29 56.94 Example 2 21.16 40.84 46.53 60.92 Example 3 29.17 44.1 64.42 73.45 Example 4 58.25 67.72 80.09 97.1
[0064] The hydrogel in the comparative example has no self-healing ability.
[0065] The stress-strain curves of the maleic acid acrylamide copolymer hydrogel prepared in Example 4 after different healing times are as follows: Figure 2 As shown, the maximum compressive strengths after 0.5h, 12h, 24h and 48h of healing are 0.31MPa, 0.36MPa, 0.42MPa and 0.52MPa, respectively.
[0066] With the increase of maleic acid content, the self-healing efficiency of hydrogel increases significantly, and the sample in the most embodiment 4 containing maleic acid is after healing 30min, and its self-healing efficiency is up to 58.25%, and after healing 48h, the maximum stress of hydrogel is almost consistent with before healing, and self-healing efficiency can reach 97.1%. The addition of maleic acid introduces a carboxyl group, and in the hydrogel self-healing process, a reversible hydrogen bond interaction is formed between the carboxyl group in maleic acid and the amide group of acrylamide and choline chloride, and the more the content of maleic acid, the more the carboxyl group contained, and the more the reversible hydrogen bond network formed is more abundant. In addition, the abundance of the reversible bond network is positively correlated with the hydrogel self-healing time, and with the extension of the self-healing time, the hydrogel self-healing efficiency continues to increase.
[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing maleic acid acrylamide copolymer hydrogel, characterized in that: The following steps are involved: S1: A hydrogen bond donor, a hydrogen bond acceptor and a cross-linking agent are mixed and stirred in an oil bath at 70°C until a transparent and clear liquid is obtained, and then allowed to stand and cool to room temperature to obtain a deep eutectic solvent, wherein the hydrogen bond donor is acrylamide, the hydrogen bond acceptor is choline chloride, the cross-linking agent is N, N-methylenebisacrylamide, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:2-3, and the amount of the cross-linking agent is 0.5-1% of the total mass of the deep eutectic solvent; S2: adding an initiator and maleic acid to the deep eutectic solvent at a temperature not lower than 32° C., stirring evenly to form a mixture solution, transferring the formed mixture solution to a tubular reactor, heating the reactor with a heat source to initiate a polymerization reaction, using the deep eutectic solvent as a reaction solvent to initiate thermal front-end polymerization, achieving copolymerization of low-activity monomers and high-activity monomers through front-end polymerization, and then removing the heat source until the mixture solution in the entire reactor is completely converted into a polymer gel, wherein the initiator is potassium persulfate, and the amount of the initiator is 0.25-0.5% of the total mass of the deep eutectic solvent, and the amount of the maleic acid is 2.34-9.37% of the total mass of the deep eutectic solvent; S3: After soaking and washing the polymer gel, freeze-drying is performed to obtain a maleic acid acrylamide copolymer hydrogel, which is white in color.
2. A maleic acid acrylamide copolymer hydrogel, characterized in that: Prepared by the method described in claim 1.