A method for constructing high porosity dual-network porous materials using surfactant stabilized foam templates

Abstract

This invention discloses a method for constructing a high-porosity dual-network porous material using a surfactant-stabilized foam template, belonging to the field of porous material preparation technology. The method includes the following steps: dissolving a soluble polymer, a crosslinking agent, a water-soluble polymeric monomer, an initiator, and a surfactant in water; then adding glutaraldehyde and stirring to foam the mixture to obtain a water-based foam; the soluble polymer can chemically bond with glutaraldehyde; the water-based foam is subjected to a polymerization reaction, and after the polymerization reaction is completed, it is dried to obtain the high-porosity dual-network porous material. This invention uses a foam template method, stabilizing the surfactant-generated foam through the chemical bonding between glutaraldehyde and the soluble polymer, to prepare a dual-network porous material with high porosity and high mechanical strength. The method is simple, environmentally friendly, and highly universal and practical, improving upon the problems of high energy consumption, cumbersome steps, and low material porosity in current porous material construction methods.

Description

Technical Field

[0001] This invention relates to the field of porous material preparation technology, and in particular to a method for constructing a high-porosity dual-network porous material using a surfactant-stabilized foam template. Background Technology

[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Currently, commonly used methods for constructing lightweight, high-porosity three-dimensional porous materials include freeze-drying, 3D printing, pore-forming agent etching, and emulsion template technology. However, these methods require sophisticated equipment, consume high energy during production, involve cumbersome steps, and cause significant secondary pollution, hindering large-scale production and application expansion. Foam, as a gas-liquid dispersion system, can produce porous gel foam encapsulating gas after its liquid film is fixed. The introduction of gas can create pores in situ within the material without the need for subsequent removal of the pore-forming agent. Using foam gel as a template to construct porous materials is a more environmentally friendly and convenient method.

[0004] However, foam systems, when used as templates, are highly susceptible to instability during use; therefore, foam stability is crucial for maximizing its template function. Amphiphilic particles and molecules are commonly used as foam stabilizers. Amphiphilic particles can irreversibly adsorb at the gas-liquid interface, forming an interfacial elastic film that hinders further diffusion of gas molecules, exhibiting good foam stability. However, porous materials obtained from particle-stabilized foam templates typically suffer from low porosity and high density, limiting their application development. A wide variety of soluble amphiphilic molecules, such as surfactants, are also frequently used for gas-liquid interface stabilization. By gelling the liquid film, high-porosity porous materials can be further obtained. However, surfactant molecules easily detach from the gas-liquid interface, leading to foam template instability. Therefore, ensuring the stability of surfactant-stabilized foam templates during use is critical for preparing high-porosity porous materials. Summary of the Invention

[0005] In view of this, the present invention provides a method for constructing a high-porosity dual-network porous material using a surfactant-stabilized foam template. The method provided by the present invention is environmentally friendly and energy-efficient, and can produce porous materials with high porosity and high mechanical strength.

[0006] In a first aspect, the present invention provides a method for constructing a high-porosity dual-network porous material using a surfactant-stabilized foam template, comprising the following steps:

[0007] A soluble polymer, a crosslinking agent, a water-soluble monomer, an initiator, and a surfactant are dissolved in water, and then glutaraldehyde is added. The mixture is stirred and foamed to obtain a water-based foam. The soluble polymer can form a chemical bond with glutaraldehyde.

[0008] The water-based foam is subjected to a polymerization reaction, and then dried after the polymerization reaction is completed to obtain a high-porosity dual-network porous material.

[0009] Preferably, the soluble polymer is selected from chitosan or polyvinyl alcohol.

[0010] Furthermore, when the soluble polymer is chitosan, the chitosan is dissolved in water in the form of a chitosan-acetic acid aqueous solution, and the polymerization reaction is completed with a step of removing acetic acid.

[0011] Preferably, the crosslinking agent is N,N'-methylenebisacrylamide; the water-soluble polymeric monomer is selected from one or both of acrylic acid and acrylamide; and the initiator is selected from azobisisobutylamidine hydrochloride.

[0012] Preferably, the surfactant is an amphoteric surfactant, a cationic surfactant, or a nonionic surfactant.

[0013] Preferably, in the water-based foam, the mass ratio of glutaraldehyde, soluble polymer, crosslinking agent, water-soluble polymeric monomer, initiator and surfactant is (12-20):(40-60):(5-10):(250-350):(15-25):(25-40); and the mass fraction of glutaraldehyde is 0.5-1 wt%.

[0014] Preferably, the stirring and foaming speed is 6000-10000 r / min; the stirring and foaming time is 40-120 s.

[0015] Preferably, the polymerization reaction temperature is 60–90°C and the polymerization reaction time is 5–30 min.

[0016] Preferably, the drying temperature is 10–40°C.

[0017] Secondly, the present invention provides a high-porosity dual-network porous material prepared by the above method.

[0018] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0019] (1) The present invention adopts the foam template method, which stabilizes the foam generated by the surfactant through the chemical bonding of glutaraldehyde and soluble polymer. The polymer formed by the free radical polymerization reaction of water-soluble polymer monomers and the soluble polymer are used as a double network skeleton to prepare a double network porous material with high porosity and high mechanical strength. The method of the present invention is simple, environmentally friendly, universal and practical, and improves the problems of high energy consumption, complicated steps and low material porosity of the current porous material construction methods.

[0020] (2) The high porosity dual-network porous material prepared by the present invention has a porosity of over 80%, a low density, a pore size of over 50 μm, and a hydrophilic porous framework structure. It has broad application prospects in environmental remediation, cell culture, electrochemical energy storage and catalysis. Attached Figure Description

[0021] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation thereof. Obviously, those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0022] Figure 1 The microstructure of the CAB foam sample, CAB-CS foam sample, and CAB-CS-GA foam sample in Example 1 of this invention is shown in (a). 1～ a3), bubble size (b), foaming ability (c), and foam stabilization result (d), where a1 is the microstructure of the CAB foam sample, a2 is the microstructure of the CAB-CS foam sample, and a3 is the microstructure of the CAB-CS-GA foam sample.

[0023] Figure 2 This is the rheological characterization of the CAB-CS foam sample and the CAB-CS-GA foam sample in Example 1 of the present invention, wherein a is the change of storage modulus (G') and loss modulus (G”) over time; b is the steady-state shear result; and c is the stress scan result.

[0024] Figure 3 These are macroscopic images of the dual-network porous materials prepared in Examples 3, 4 and 5 of the present invention, wherein a is Example 3, b is Example 4 and c is Example 5;

[0025] Figure 4 These are macroscopic images of the water-based foam (a1-a4) and dual-network porous material (b1-b4) of Comparative Examples 1, 2, 3 and 2 of the present invention;

[0026] Figure 5These are scanning electron microscope images of the dual-network porous materials of Comparative Example 4 and Example 2 of the present invention, wherein a is Comparative Example 4 and b is Example 2;

[0027] Figure 6 The results (a) and (b) are the pore size distribution and porosity characterization results of the dual-network porous materials of Comparative Example 4 and Example 2 of this invention. Detailed Implementation

[0028] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] This invention provides a method for constructing a high-porosity dual-network porous material using a surfactant-stabilized foam template, comprising the following steps:

[0030] A soluble polymer, a crosslinking agent, a water-soluble monomer, an initiator, and a surfactant are dissolved in water, and then glutaraldehyde is added. The mixture is stirred and foamed to obtain a water-based foam. The soluble polymer can form a chemical bond with glutaraldehyde.

[0031] The water-based foam is subjected to a polymerization reaction, and then dried after the polymerization reaction is completed to obtain a high-porosity dual-network porous material.

[0032] In the above-mentioned technical solution of the present invention, the surfactant has good foaming properties and can form a large amount of foam during stirring and foaming. Glutaraldehyde and soluble polymers can undergo a chemical reaction between the foam liquid film to generate a three-dimensional network structure, thereby preventing the leakage of gas molecules in the foam and making the generated bubbles smaller, avoiding bubble merging and drainage, thus assisting the amphiphilic small molecule surfactant to play a good stabilizing role on the foam template. In addition, the introduction of glutaraldehyde and soluble polymers can also prevent the foam structure from collapsing during the free radical polymerization process, giving full play to the template role of the foam. Water-soluble free radical polymerizing monomers undergo polymerization under the action of initiator and form a three-dimensional network under the action of crosslinking agent, thereby forming a double network skeleton together with soluble polymers, improving the mechanical properties of the double network porous material.

[0033] In this invention, the soluble polymer is selected from chitosan or polyvinyl alcohol. Chitosan can undergo a Schiff base reaction with glutaraldehyde, and polyvinyl alcohol can undergo an aldol condensation reaction with glutaraldehyde. Further, when the soluble polymer is chitosan, the chitosan is dissolved in water in the form of a chitosan-acetic acid aqueous solution, and the polymerization reaction includes a step of removing acetic acid after completion. This invention does not impose special limitations on the preparation method of the chitosan-acetic acid aqueous solution; commonly used methods in the art are acceptable. In this invention, the mass fraction of chitosan in the chitosan-acetic acid aqueous solution is preferably 5-7 wt%, and the mass fraction of acetic acid is preferably 6-8 wt%. This invention also does not impose special limitations on the step of removing acetic acid. This invention preferably uses an alkaline solution soaking method to neutralize the acetic acid, followed by multiple rinsing with deionized water to remove the alkaline solution.

[0034] In this invention, the crosslinking agent is N,N'-methylenebisacrylamide; the crosslinking agent enables crosslinking reactions between macromolecular chains to form a three-dimensional network structure, further improving the mechanical properties of the porous material. The water-soluble polymerizable monomer is selected from one or both of acrylic acid and acrylamide; the initiator is selected from azobisisobutylamidine hydrochloride.

[0035] In this invention, the surfactant is an amphoteric surfactant, a cationic surfactant, or a nonionic surfactant. This invention does not impose any special restrictions on the specific type of surfactant; those skilled in the art can select one according to actual needs. For example, the amphoteric surfactant can be cocopropylamide betaine (CAB), the cationic surfactant can be hexadecyltrimethylammonium bromide (CTAB), and the nonionic surfactant can be fatty alcohol polyoxyethylene ether (AEO).

[0036] In this invention, the mass ratio of glutaraldehyde, soluble polymer, crosslinking agent, water-soluble polymeric monomer, initiator and surfactant in the water-based foam is (12-20):(40-60):(5-10):(250-350):(15-25):(25-40); the mass fraction of glutaraldehyde is 0.5-1 wt%, more preferably 0.5-0.7 wt%.

[0037] In this invention, the stirring and foaming speed is 6000–10000 r / min; the stirring and foaming time is 40–120 s. This invention does not impose special limitations on the stirring and foaming equipment; commonly used stirring and foaming equipment in the art can be used.

[0038] In this invention, the polymerization reaction temperature is 60–90°C, and the polymerization reaction time is 5–30 min. This invention preferably uses thermal initiation for polymerization, but other methods such as photoinitiation and redox initiation can also be used. Those skilled in the art can choose according to actual needs.

[0039] In this invention, the drying temperature is 10–40°C. The drying process can be carried out at room temperature, i.e., natural drying. During this process, moisture evaporates slowly, avoiding the adverse effects of heating on the structure, and no heating or freezing is required, thus resulting in low energy consumption.

[0040] The present invention also provides a high-porosity dual-network porous material prepared by the above method, which has a porosity of over 80% and good mechanical properties, with a Young's modulus of over 500 kPa.

[0041] The technical solution of the present invention will be further described below with reference to specific embodiments. The present invention does not impose any special restrictions on the source of reagents used in the following embodiments; commercially available products well known to those skilled in the art can be used.

[0042] Example 1

[0043] This embodiment investigates the effects of different components on the microstructure, foaming properties, and stability of foam samples.

[0044] The foam sample was prepared as follows:

[0045] (1) CAB foam sample: Dissolve 0.03g of cocopropylamide betaine (CAB) in 2.53g of water to prepare a CAB aqueous solution with a mass fraction of 1.18wt%. Then, use a variable speed disperser to stir and foam at a speed of 8000r / min for 60s to obtain a CAB foam sample.

[0046] (2) CAB-CS foam sample: 1.296 g of chitosan (CS) powder was added to 21.6 g of 7.4 wt% glacial acetic acid aqueous solution, and stirred and heated at 80 °C for 8 h to obtain a 5.66 wt% CS-acetic acid aqueous solution. 0.8 g of the 5.66 wt% CS-acetic acid aqueous solution and 1.73 g of an aqueous solution containing 0.03 g of cocopropylamide betaine (CAB) were thoroughly mixed, and then stirred and foamed at 8000 r / min for 60 s using a variable speed disperser to obtain the CAB-CS foam sample.

[0047] (3) CAB-CS-GA foam sample: 1.296g of chitosan (CS) powder was added to 21.6g of 7.4wt% glacial acetic acid aqueous solution and stirred and heated at 80℃ for 8h to obtain 5.66wt% CS-acetic acid aqueous solution. 0.8g of 5.66wt% CS-acetic acid aqueous solution and 1.53g of aqueous solution containing 0.03g of cocopropylamide betaine (CAB) were mixed, and finally 0.2g of 7.5wt% glutaraldehyde (GA) aqueous solution was added. Then, the mixture was stirred and foamed for 60s using a variable speed disperser at 8000r / min to obtain the CAB-CS-GA foam sample.

[0048] The microstructure of the CAB foam samples, CAB-CS foam samples, and CAB-CS-GA foam samples was observed using a microscope, and the bubble size was statistically analyzed. Figure 1 As shown. By Figure 1 As shown in a1(CAB), a2(CAB-CS), a3(CAB-CS-GA), and b, the size distribution range of bubbles narrows with the addition of chitosan and glutaraldehyde, indicating that CS and GA contribute to the formation of smaller and more uniformly distributed stable foams. The average bubble size of foam stabilized by surfactant (CAB) alone is approximately 106.12 μm. When CS or CS and GA are added, the average bubble sizes of the foam samples are approximately 54.99 μm and 48.25 μm, respectively. In other words, bubbles at the gas-liquid interface stabilized by CAB alone may coalesce and drain more quickly. During this process, the size of air bubbles increases continuously, and the distribution becomes irregular, leading to rapid foam defoaming. However, with the introduction of CS, CS, and GA, bubbles can be stabilized and protected in the early stages, thus maintaining a smaller and more uniform size, which gives the foam system higher stability.

[0049] Depend on Figure 1 As shown in 'c', the foaming abilities of the CAB, CAB-CS, and CAB-CS-GA foam samples are 342.86%, 222.21%, and 225.14%, respectively. This indicates that the foaming ability decreases when polymer CS is introduced into the CAB aqueous solution, which means that the high viscosity of the CS liquid may hinder the diffusion of CAB surfactant molecules from the bulk phase to the interface.

[0050] Stability is assessed by measuring the change in foam volume over time (see...). Figure 1(d) Like most foams stabilized by small-molecule surfactants, CAB foam has a short lifespan, completely collapsing within 55 minutes. Compared to CAB and CAB-CS foam samples, the stability of CAB-CA-GA foam was significantly enhanced by the addition of the crosslinking agent GA. It is speculated that a Schiff base reaction between the polymer CS and the crosslinking agent GA occurred in the CAB-CS-GA foam liquid film, forming a 3D network that prevented the escape of gas molecules and provided an ultra-stable gel foam template.

[0051] The rheological characterization of the above CAB-CS foam samples and CAB-CS-GA foam samples was performed, such as... Figure 2 As shown in Figure a, the changes in storage modulus (G') and loss modulus (G”) of the foam samples over time were first tested. For CAB-CS foam, G” was greater than G' within 1200 seconds, indicating that the CAB-CS foam sample exhibited liquid properties. For the foam sample with added GA, G” was initially also greater than G', then G' equaled G” at 178 seconds. Afterward, the value of G' exceeded G”, indicating that a 3D network structure was formed in the liquid film of the CAB-CS-GA foam as the Schiff base reaction between CS and GA proceeded. Steady-state shear results (see...) Figure 2 In section b), all foams exhibit shear thinning. With increasing shear rate, the apparent viscosity gradually decreases. The addition of GA imparts a higher apparent viscosity to the foam. For the stress scan test of CAB-CS-GA, at low stresses, G” and G’ remain constant, with G’ being higher than G”; this region is the linear viscoelastic region. In this region, as stress continues to increase, G’ and G” begin to decrease until they are equal, at which point the yield stress point is considered reached. Under sufficiently high stresses, G” is greater than G’, indicating a transition from an elastic state to a viscous state, as shown in section b). Figure 2 As shown in c, within the test frequency range, the value of G' is approximately one order of magnitude higher than G”, indicating the solid-like properties of CAB-CS-GA foam. However, no linear viscoelastic region was observed in CAB-CS foam, and G” is greater than G', indicating its liquid-like properties. These phenomena further confirm the importance of the Schiff base reaction in maintaining the stability of the foam template. GA can react with CS to form a three-dimensional network, which can encapsulate gas molecules and bind with water molecules, suppressing drainage and maintaining the integrity of the foam template. Therefore, CAB-CS-GA foam was subsequently introduced into the construction of dual-network porous materials.

[0052] Example 2

[0053] This embodiment provides a method for preparing high-porosity dual-network porous materials using surfactant-stabilized foam templates.

[0054] (1) 1.296 g of chitosan (CS) powder was added to 21.6 g of glacial acetic acid aqueous solution with a concentration of 7.4 wt%, and stirred and heated at 80 °C for 8 h to obtain 5.66 wt% CS-acetic acid aqueous solution.

[0055] (2) Mix 0.8 g of water, 0.8 g of 5.66 wt% CS-acetic acid aqueous solution (containing 0.0453 g CS), 0.4 g of 2 wt% N,N'-methylenebisacrylamide aqueous solution (MBA, containing 0.008 g MBA), and 0.2 g of acrylic acid (AA) in a 10 mL beaker until homogeneous. Then, add 0.08 g of acrylamide (AAm), 0.03 g of cocopropylamide betaine (CAB), and 0.02 g of azobisisobutylamidine hydrochloride (AIBA), stir to dissolve, and finally add 0.2 g of 7.5 wt% glutaraldehyde (GA, containing 0.015 g GA) solution. Immediately afterward, use a variable speed disperser to stir and foam at 8000 r / min for 60 s to obtain water-based foam.

[0056] (3) The water-based foam was heated in a water bath at 80°C for 10 minutes to induce a polymerization reaction. After the reaction was complete, it was immersed in a 0.5 mol / L sodium hydroxide solution for about 5 hours, and then washed three times with deionized water to remove excess acetic acid, thus obtaining hydrogel foam. The hydrogel foam was left at room temperature for 12 hours to obtain a dry double-network porous material with a density of 0.198 g / cm³. 3 .

[0057] Example 3

[0058] The difference between this embodiment and Example 2 is that the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) is used instead of cocopropylamide betaine (CAB). A macroscopic image of the dual-network porous material prepared in this embodiment is shown below. Figure 3 As shown in 'a', it can be seen that a double-network porous foam material has been successfully constructed.

[0059] Example 4

[0060] The difference between this embodiment and Example 2 is that the nonionic surfactant fatty alcohol polyoxyethylene ether (AEO3) is used instead of coconut oil propylamide betaine (CAB). A macroscopic image of the dual-network porous material prepared in this embodiment is shown below. Figure 3 As shown in b, a double-network porous foam material has been successfully constructed.

[0061] Example 5

[0062] The difference between this embodiment and Embodiment 2 is that polyvinyl alcohol is used instead of chitosan in this embodiment. The specific steps are as follows:

[0063] (1) Add 1.2g of polyvinyl alcohol (PVA) to 20g of water and heat it in a water bath at 80℃ for 12h to obtain a completely dissolved PVA aqueous solution as a stock solution for later use.

[0064] (2) Mix 0.8 g of water, 0.8 g of 6 wt% PVA aqueous solution (containing 0.048 g PVA), 0.4 g of 2 wt% N,N'-methylenebisacrylamide aqueous solution (MBA, containing 0.008 g MBA), and 0.2 g of acrylic acid (AA) in a 10 mL beaker until homogeneous, and adjust the pH of the solution to 2-3 using hydrochloric acid. Then, add 0.08 g of acrylamide (AAm), 0.03 g of cocopropylamide betaine (CAB), and 0.02 g of azobisisobutylamidine hydrochloride (AIBA), stir to dissolve, and finally add 0.2 g of 7.5 wt% glutaraldehyde (GA, containing 0.015 g GA) solution. Immediately afterward, use a variable speed disperser to stir and foam at 8000 r / min for 60 s to obtain water-based foam. React the foam in an 80℃ water bath for ten minutes to undergo free radical polymerization, thus obtaining a double-network porous foam material.

[0065] Macroscopic images of the dual-network porous material prepared in this embodiment are shown below. Figure 3 As shown in c, it can be seen that a double-network porous foam material has been successfully constructed.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 2 is that no CS-acetic acid aqueous solution and glutaraldehyde solution are added to the water-based foam in this comparative example. The missing mass is made up by water to ensure that the mass fraction of other substances remains unchanged.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 2 is that no glutaraldehyde solution is added to the water-based foam in this comparative example, and the missing mass is made up by water to ensure that the mass fraction of other substances remains unchanged.

[0070] Comparative Example 3

[0071] The difference between this comparative example and Example 2 is that the amount of 7.5wt% glutaraldehyde solution added to the water-based foam in this comparative example is 0.05g (containing 3.75mg GA), and the missing mass is made up by water to ensure that the mass fraction of other substances remains unchanged.

[0072] Comparative Example 4

[0073] The difference between this comparative example and Example 2 is that cocopropylamide betaine (CAB) is not added to the aqueous solution of this comparative example, and the missing mass is made up by water to ensure that the mass fraction of other substances remains unchanged.

[0074] Test case

[0075] 1. Macroscopic images of water-based foam and corresponding dual-network porous materials:

[0076] Figure 4 Macroscopic images of the water-based foams (a1-a4) and dual-network porous materials (b1-b4) of Comparative Examples 1, 2, 3, and 2 show that foam can be obtained after foaming in the absence of the crosslinking agent GA, but only a gel is formed after heating to initiate a free radical polymerization reaction, and the bubbles completely disappear (see...). Figure 4 In the example of a1-a2 and b1-b2), the foam structure in the dual-network porous material of Example 2 was well preserved (see a1-a2 and b1-b2). Figure 4 (a4 and b4 in the original text) This indicates that the introduction of the Schiff base reaction can prevent the collapse of the foam template during free radical polymerization, thus producing a stable dual-network porous material. It is noteworthy that when the concentration of the crosslinking agent (GA) is too low (Comparative Example 3, GA concentration of 0.148 wt%), the foam template still disappears, resulting only in a gel (see [link to original text]). Figure 4 (a3 and b3 in the original text). These results indicate that the crosslinking rate of CS and GA is a key factor in maintaining the stability of the foam template to generate a dual-network structure. In other words, the stability of the foam template should match the reaction rate of the free radical polymerization on a time scale. An appropriate GA concentration can provide a stable foam system during free radical polymerization, thus successfully constructing a dual-network porous foam.

[0077] 2. Mechanical properties

[0078] The CAB-CS-GA foam sample from Example 1 was dried at room temperature for 12 hours to obtain a single-network foam sample CG. The Young's modulus of the single-network porous material CG and the double-network porous material (CGAA) from Example 2 were measured. The Young's modulus of the single-network porous material CG was 259.02 kPa, and the Young's modulus of the double-network porous material CGAA from Example 2 was 552.45 kPa. This shows that the mechanical properties were significantly improved after introducing the poly(acrylamide-acrylic acid) network.

[0079] 3. Microstructure characterization

[0080] Porosity is a key parameter characterizing the structure of porous materials. The microstructure and pore size distribution of the porous materials constructed in Example 2 and Comparative Example 4 were analyzed using SEM observation and mercury intrusion measurement. Figure 5 The SEM images in Figure b show that, in Example 2, the dual-network porous material prepared using foam as a template has a richer and more interconnected porous structure. In contrast, the dual-network material in Comparative Example 4, which uses gel as a template without surfactant, has a denser pore structure.

[0081] Mercury intrusion measurement (mercury porosimetry) is often used to test the pore size distribution and porosity of macroporous materials. For example... Figure 6 As shown in a and b, the dual-network gel material in Comparative Example 4 and the dual-network foam gel material in Example 2 both exhibit macroporous structures with average pore sizes of 11.10 μm and 64.16 μm, respectively, but porosities of 38.29% and 89.45%, respectively. These results strongly demonstrate that by introducing a foam template, the pore size and porosity of porous materials are significantly improved.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for constructing a high-porosity dual-network porous material using a surfactant-stabilized foam template, characterized in that, Includes the following steps: A soluble polymer, a crosslinking agent, a water-soluble monomer, an initiator, and a surfactant are dissolved in water, and then glutaraldehyde is added. The mixture is stirred and foamed to obtain a water-based foam. The soluble polymer can form a chemical bond with glutaraldehyde. The stirring speed is 6000~8000 r / min. The stirring time is 60~120 s. The water-based foam is subjected to a polymerization reaction, and then dried after the polymerization reaction is completed to obtain a high-porosity dual-network porous material. The soluble polymer is selected from chitosan or polyvinyl alcohol.

2. The method as described in claim 1, characterized in that, When the soluble polymer is chitosan, the chitosan is dissolved in water in the form of a chitosan-acetic acid aqueous solution, and the polymerization reaction is completed with a step of removing acetic acid.

3. The method as described in claim 1, characterized in that, The crosslinking agent is N,N'-methylenebisacrylamide; the water-soluble polymerizable monomer is selected from one or both of acrylic acid and acrylamide; the initiator is selected from azobisisobutylamidine hydrochloride.

4. The method as described in claim 1, characterized in that, The surfactant is an amphoteric surfactant, a cationic surfactant, or a nonionic surfactant.

5. The method as described in claim 1, characterized in that, In the water-based foam, the mass ratio of glutaraldehyde, soluble polymer, crosslinking agent, water-soluble polymeric monomer, initiator and surfactant is (12~20): (40~60): (5~10): (250~350): (15~25): (25~40); the mass fraction of glutaraldehyde is 0.5~1wt%.

6. The method as described in claim 1, characterized in that, The polymerization reaction is carried out at a temperature of 60~90℃ for a time of 5~30 min.

7. The method as described in claim 1, characterized in that, The drying temperature is 10~40℃.

8. The high-porosity dual-network porous material prepared by the method according to any one of claims 1 to 7.

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