Preparation method of high-strength and high-toughness gel
Through the physical blending method of polymers, alcohol organic solvents and low boiling point solvents, the problem of cumbersome gel preparation process is solved, and the rapid, simple and large-scale preparation of high-strength and high-toughness gels is achieved, with low cost and environmentally friendly advantages.
Patent Information
- Application Number
- CN202411828277.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-02-21
AI Technical Summary
The preparation process of traditional high-performance gels is cumbersome and difficult to amplify, limiting their application range.
The mechanical properties of the gel are enhanced by physical blending of polymers containing specific functional functional groups with alcohol organic solvents and low boiling solvents.
It realizes rapid and large-area preparation of high-strength and high-toughness gels. The method is simple, easy to amplify, and is cheap and green and environmentally friendly.
Smart Images
Figure CN119490675A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of gel preparation, and more specifically relates to a high-strength and high-toughness gel and a preparation method thereof. Background Art
[0002] The poor mechanical properties of traditional gels greatly limit their scope of application. Therefore, in recent years, people have developed a variety of methods to improve the mechanical properties of gels, mainly including improving the toughness and mechanical strength of gels by modifying covalent networks; technicians in this field usually refer to gels with a strength higher than 0.4MPa and a toughness not lower than 1MJ / m2 as high-strength, high-toughness gels. Introduce a cross-linking agent or a second monomer, and use ultraviolet light-induced curing technology to enhance the mechanical strength of the gel. However, these methods generally have the problem of cumbersome preparation process and difficulty in scale-up, so it is difficult to promote and apply. Therefore, it is urgent to find a simpler and more effective solution to promote the widespread application of gel materials. Summary of the invention
[0003] In view of the above defects or improvement needs of the prior art, the purpose of the present invention is to provide a method for preparing high-strength and high-toughness gel, effectively solve the problem that the traditional high-performance gel preparation process is cumbersome and difficult to scale up, and provide a new solution for the preparation of high-strength and high-toughness gel.
[0004] The technical solution of the present invention is achieved in this way: it comprises the following steps:
[0005]
[0006] The polymer of the general formula is uniformly mixed with an alcohol organic solvent and a low boiling point solvent, and then the low boiling point solvent is removed to obtain a high-strength and high-toughness gel.
[0007] The polymer contains one or more of hydroxyl, amide, amino, carboxyl, thiol, imidazole, boric acid, pyrimidone, and phosphate functional groups; the molecular weight of the polymer is not less than 10,000 Da.
[0008] Preferably, the polymer is one or both of polyvinyl pyrrolidone and polyacrylic acid.
[0009] The alcohol organic solvent is selected from one or more of ethylene glycol, glycerol, diethylene glycol, triethylene glycol, or polyethylene glycol and polypropylene glycol with a molecular weight of 200, 400, 600, 800. The alcohol organic solvent is a liquid small molecule solvent or liquid oligomer with a boiling point higher than 150° C., and its mass proportion in the gel system is 5-50%.
[0010] The low boiling point solvent is a solvent with a boiling point not higher than 100°C.
[0011] Preferably, the low boiling point solvent is one or more of water, ethanol, n-hexane, cyclohexane, and tetrahydrofuran. The removal of the low boiling point solvent is achieved by one or more of the following methods: evaporation at elevated temperature, evaporation at reduced pressure, rotary evaporation, or spraying.
[0012] As a further preferred embodiment of the present invention, the prepared high-strength and high-toughness gel has a strength higher than 0.4 MPa and a toughness not lower than 1 MJ / m2.
[0013] The polymer is a polymer that can form non-covalent cross-linking with an alcohol organic solvent; the non-covalent bond is any one of ionic bond interaction, hydrogen bond interaction, electrostatic interaction, hydrophilic-hydrophobic interaction, halogen bond, host-guest recognition, dynamic boron ester bond, disulfide bond and coordination bond interaction; the polymer is a solid with a glass transition temperature higher than 25°C;
[0014] Compared with the prior art, the present invention can achieve the following beneficial effects:
[0015] (1) The method is simple and easy to scale up: The present invention combines polymers and solvents by physical blending to achieve rapid, large-scale preparation of high-strength, high-toughness gels. The cross-linking effect of low-boiling-point solvents on the polymer network and the entanglement between polymer molecular chains are used to improve the mechanical strength and toughness of the gel. Compared with traditional methods that rely on chemical modification or the introduction of cross-linking agents and ultraviolet light curing, the present invention does not involve complex chemical reactions, the operating steps are simpler, and the conditions are easy to control, which is conducive to large-scale production.
[0016] (2) The present invention is low-cost and environmentally friendly: The polymer used in the present invention is preferably polyvinyl pyrrolidone and polyacrylic acid, the alcohol organic solvent is polyethylene glycol or polypropylene glycol with a molecular weight of 200, 400, 600, 800, or ethylene glycol, glycerol, diethylene glycol, triethylene glycol with a high boiling point, and the low boiling point solvent is preferably ethanol or water. The above raw materials are all low-priced and can be industrially produced. These raw materials are combined by simple physical blending technology to prepare high-performance gel, which effectively reduces the production cost of the material and facilitates the promotion and application of the method.
[0017] In summary, the present invention adopts a one-step physical blending method of polymer and solvent, introduces a solvent that can produce non-covalent cross-linking with the polymer, and utilizes the entanglement of polymer molecular chains to improve the mechanical properties of the gel, thereby achieving simple and rapid large-scale preparation of high-strength and high-toughness gel materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for describing the embodiments or the prior art are briefly introduced below.
[0019] Figure 1 Schematic diagram of the high-strength, high-toughness gel prepared by solvent volatilization or rotary evaporation in Examples 1-4 and the interactions existing therein.
[0020] Figure 2 This is the stress-strain curve (25° C., strain rate 20 mm / min) of the gel with high strength and high toughness prepared in Examples 1-4.
[0021] Figure 3 This is an optical photograph of polyvinyl pyrrolidone with a molecular weight of 1,300,000 and ethylene glycol in Comparative Example 1.
[0022] Figure 4 The rheological curve and optical photograph of the gel prepared in Comparative Example 2 (inset).
[0023] Figure 5 This is the stress-strain curve of the gel prepared in Comparative Example 3 (25°C, strain rate 20 mm / min).
[0024] Figure 6 This is the stress-strain curve of the gel prepared in Comparative Example 4 (25°C, strain rate 20 mm / min). DETAILED DESCRIPTION
[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The following is a specific embodiment:
[0026] Example 1
[0027] The present application provides a high-strength and high-toughness gel, and the specific preparation method comprises the following steps:
[0028] (1) Polyvinyl pyrrolidone with a molecular weight of 1,300,000 and polyethylene glycol with a molecular weight of 200 are dispersed in water by magnetic stirring and fully mixed to form a mixed solution; wherein the mass ratio of polyvinyl pyrrolidone to polyethylene glycol is 6:4.
[0029] (2) The mixed solution is injected into a mold, and the solvent is evaporated at 85°C for 4 hours, and then vacuum dried for 12 hours to obtain a high-strength and high-toughness gel. The mechanical properties of the gel are as follows: Figure 2As shown in a. Polyvinyl pyrrolidone with a molecular weight of 1300000 and polyethylene glycol oligoether that can form hydrogen bonds with polyvinyl pyrrolidone are selected in the gel. By adjusting the mass ratio of polyethylene glycol oligoether to polyvinyl pyrrolidone to 4:6, a high-strength and high-toughness gel with a tensile strength of 1MPa and a toughness of 3.4MJ / m2 is obtained. It can be seen that by selecting an oligoether liquid that forms hydrogen bonds with a high molecular weight polymer as an alcohol organic solvent and adjusting the proportion of the alcohol organic solvent in the gel system, a high-strength and high-toughness gel with a tensile strength higher than 0.4MPa and a toughness not less than 1MJ / m2 can be obtained.
[0030] Example 2
[0031] The present application provides a high-strength and high-toughness gel, and the specific preparation method comprises the following steps:
[0032] (1) Polyvinyl pyrrolidone with a molecular weight of 1,300,000 and ethylene glycol are dispersed in water by magnetic stirring and fully mixed to form a mixed solution; wherein the mass ratio of polyvinyl pyrrolidone to ethylene glycol is 6:4.
[0033] (2) The mixed solution is injected into a mold, and the solvent is evaporated at 85°C for 4 hours, and then vacuum dried for 12 hours to obtain a high-strength and high-toughness gel. The mechanical properties of the gel are as follows: Figure 2 b. Different from Example 1, Example 2 selects ethylene glycol small molecules that can form hydrogen bonds with polyvinyl pyrrolidone as alcohol organic solvents, and obtains high-strength and high-toughness gels with tensile strength of 1 MPa and toughness of 7.8 MJ / m2. It can be seen that by selecting liquid small molecules that form hydrogen bonds with high molecular weight polymers, high-strength and high-toughness gels with tensile strength higher than 0.4 MPa and toughness not lower than 1 MJ / m2 can also be obtained.
[0034] Example 3
[0035] The present application provides a high-strength and high-toughness gel, and the specific preparation method comprises the following steps:
[0036] (1) Polyvinyl pyrrolidone with a molecular weight of 1,300,000 and glycerol are dispersed in water by magnetic stirring and fully mixed to form a mixed solution; wherein the mass ratio of polyvinyl pyrrolidone to glycerol is 6:4.
[0037] (2) The mixed solution is injected into a mold, the solvent is evaporated at 85°C for 4 hours, and vacuum dried for 12 hours to obtain a high-strength and high-toughness gel. The mechanical properties of the gel are as follows: Figure 2c. Different from Example 1 and Example 2, Example 3 selects a propylene glycol small molecule that can form hydrogen bonds with polyvinyl pyrrolidone as an alcohol solvent, and finally obtains a high-strength, high-toughness gel with a tensile strength of 0.42MPa and a toughness of 2.3MJ / m2. In summary, by selecting a liquid small molecule or liquid oligoether that forms hydrogen bonds with a high molecular weight polymer, a high-strength, high-toughness gel with a tensile strength higher than 0.4MPa and a toughness not lower than 1MJ / m2 can be obtained.
[0038] Example 4
[0039] The present application provides a high-strength and high-toughness gel, and the specific preparation method comprises the following steps:
[0040] (1) Polyvinyl pyrrolidone with a molecular weight of 58,000 and polyethylene glycol with a molecular weight of 200 are dispersed in water by magnetic stirring and fully mixed to form a mixed solution; wherein the mass ratio of polyvinyl pyrrolidone to polyethylene glycol is 7.5:2.5.
[0041] (2) The mixed solution is injected into a mold, and the solvent is evaporated at 85°C for 4 hours, and then vacuum dried for 12 hours to obtain a high-strength and high-toughness gel. The mechanical properties of the gel are as follows: Figure 2 d. Different from Example 1, Example 4 selected polyvinyl pyrrolidone with a molecular weight of 58,000, and adjusted the mass ratio of polyvinyl pyrrolidone to polyethylene glycol to 7.5:2.5, and finally obtained a high-strength, high-toughness gel with a strength of 3.67 MPa and a toughness of 1 MJ / m2. It can be seen that the selection of polyvinyl pyrrolidone with a molecular weight of 58,000 and the mixing of liquid polyethylene glycol oligoether can also obtain a high-strength, high-toughness gel with a tensile strength higher than 0.4 MPa and a toughness not lower than 1 MJ / m2.
[0042] Comparative Example 1
[0043] The comparative examples of this application provide the raw materials for preparing the high-strength and high-toughness gel in Example 2: including polyvinyl pyrrolidone with a molecular weight of 1300000 and ethylene glycol. The polyvinyl pyrrolidone with a molecular weight of 1300000 used in Example 2 is a white powder with negligible mechanical strength; ethylene glycol is a fluid liquid. The two materials are mixed in a mass ratio of 6:4 to obtain a high-strength and high-toughness gel with a strength higher than 0.4MPa and a toughness not lower than 1MJ / m2. The results show that appropriate ethylene glycol can strengthen the polymer network and form a high-strength and high-toughness gel ( Figure 3 )
[0044] Comparative Example 2
[0045] This comparative experiment adopts the same preparation method as Example 1, the only difference being that the mass ratio of polyvinyl pyrrolidone to polyethylene glycol is 2:8, and finally obtains a liquid gel ( Figure 4 ). The reason for this phenomenon is that the higher content of polyethylene glycol in the gel increases the distance between polymer chains, which leads to the plasticization of the gel network and reduces its mechanical properties. Therefore, when preparing high-strength and high-toughness gels, the proportion of alcohol organic solvents in the gel needs to be further limited, that is, the mass proportion of alcohol organic solvents in the gel system is 0-50%.
[0046] Comparative Example 3
[0047] This comparative example adopts the same preparation method as Example 1, except that the molecular weight of polyvinyl pyrrolidone used is 8000, and finally a gel with a strength of 0.1 MPa and a toughness of 0.4 MJ / m2 is obtained ( Figure 5 ). Compared with the polyvinyl pyrrolidone with a molecular weight of 1,300,000 used in Example 1, the molecular weight of the polymer is smaller and there is almost no chain entanglement between the molecular chains. Therefore, when preparing high-strength and high-toughness gels, the molecular weight of the polymer, that is, the polymer chain entanglement, is the key to preparing high-strength and high-toughness gels.
[0048] Comparative Example 4
[0049] This comparative example adopts the same preparation method as Example 1, except that the molecular weight of the polyethylene glycol used is 1000, and the gel with a strength of 0.1 MPa and a toughness of 0.4 MJ / m2 is finally obtained ( Figure 6 ). Compared with the polyethylene glycol with a molecular weight of 200 used in Example 1, the polyethylene glycol with a molecular weight of 1000 is a crystalline paste. The strong interaction between the polyethylene glycol molecular chains leads to macroscopic phase separation of the gel. This shows that high molecular weight crystalline polyethylene glycol is difficult to provide sufficient free volume for polyvinyl pyrrolidone, so it is difficult to obtain a high-strength and high-toughness gel. That is to say, when preparing a high-strength and high-toughness gel, an alcohol solvent should be selected with liquid properties.
[0050] The present invention is achieved by simply physically blending a solvent with a polymer. In this process, the selected solvent has good compatibility with the polymer. The solvent can provide additional free volume for the polymer chain, and utilize the entanglement of the polymer chain to enhance the toughness of the gel, and can also form a non-covalent cross-linking network with the polymer to improve the mechanical strength of the gel. This method is simple and easy to implement, easy to scale up, and can effectively prepare high-performance gels. All the raw materials used in the present invention are commercially available.
Claims
1. A method for preparing a high-strength and high-toughness gel, characterized in that: It includes the following steps, R1 and R2 are different functional groups; n is the degree of polymerization, n>400 The polymer of the general formula is uniformly mixed with an alcohol organic solvent and a low boiling point solvent, and then the low boiling point solvent is removed to obtain a high-strength and high-toughness gel.
2. The method for preparing a high-strength and high-toughness gel according to claim 1, characterized in that: The polymer contains one or more of hydroxyl, amide, amino, carboxyl, thiol, imidazole, boric acid, pyrimidone, and phosphate functional groups; the molecular weight of the polymer is not less than 10,000 Da.
3. The method for preparing a high-strength and high-toughness gel according to claim 1, characterized in that: The polymer is one or both of polyvinyl pyrrolidone and polyacrylic acid.
4. The method for preparing a high-strength and high-toughness gel according to claim 1, characterized in that: The alcohol organic solvent is selected from one or more of ethylene glycol, glycerol, diethylene glycol, triethylene glycol, or polyethylene glycol and polypropylene glycol with a molecular weight of 200, 400, 600, 800.
5. The method for preparing a high-strength and high-toughness gel according to claim 4, characterized in that: The alcohol organic solvent is a liquid small molecule solvent or liquid oligomer with a boiling point higher than 150° C., and its mass proportion in the gel system is 5-50%.
6. The method for preparing a high-strength and high-toughness gel according to claim 1, characterized in that: The low boiling point solvent is a solvent with a boiling point not higher than 100°C.
7. The method for preparing a high-strength and high-toughness gel according to claim 6, characterized in that: The low boiling point solvent is one or more of water, ethanol, n-hexane, cyclohexane and tetrahydrofuran.
8. The method for preparing a high-strength and high-toughness gel according to claim 1, characterized in that: The removal of the low boiling point solvent is achieved by one or more of the following methods: evaporation at elevated temperature, evaporation at reduced pressure, rotary evaporation or spraying.