A method for constructing mixed matrix membranes with continuous channels by regulating microphase separation structure

Abstract

A method for constructing a mixed matrix membrane with continuous channels by regulating microphase separation structure. In this method, a polyurethane block copolymer is prepared by reacting a polyether polyol, 4,4-diphenylmethane diisocyanate, and ethyl isocyanate acrylate to obtain a prepolymer. A 2-amino-5-fluorophenylboric acid / terbium complex, 1,6-hexanediamine, and 2,5-bis(4-aminophenoxy)biphenyl are then added to the mixture to obtain a polyurethane block copolymer. The degree of microphase separation in the block copolymer can be controlled by adjusting the ratio of soft and hard segments. The introduction of the fluorophenylboric acid / terbium complex and biphenyl groups influences the ratio and distribution of the soft and hard segments, thereby regulating the microphase separation structure. Simultaneously, a CO2-philic imidazolyl ionic liquid is introduced. Due to the varying polarity of the ionic liquid, it interacts with the polymer chains to regulate the microphase separation structure, forming a CO2-philic network channel. This ionic liquid has a high adsorption capacity for CO2, thereby achieving efficient CO2 / N2 separation performance.

Description

Technical Field

[0001] The invention belongs to the technical field of gas separation and relates to a method for constructing a mixed matrix membrane with continuous channels by regulating a microphase separation structure. Background Art

[0002] In order to cope with the harm caused by the greenhouse effect, carbon capture, utilization and storage (CCUS) technology is an important path to achieve carbon neutrality, and CO2 separation is the first step in carbon capture, utilization and storage (CCUS) technology. Effective CO2 capture technologies include low-temperature separation, chemical absorption, physical adsorption and membrane separation. Among them, membrane separation is widely used due to its advantages such as no pollution, low energy consumption and good effect. Its main challenge lies in the preparation of membrane materials with high separation efficiency. At present, due to the low separation performance of membrane materials, their further development is limited. The development and preparation of membrane materials with high permeability and high selectivity is a hot topic of current research. Traditional polymer materials have good film-forming properties and low cost, and are the main body of membrane materials. However, the "trade-off" effect of permeability and selectivity limits the application of membrane materials. Research based on polymers aims to continuously improve the permeability and selectivity of membranes.

[0003] Ether-containing block copolymer membranes combine the unique properties of plastics and rubbers. Their microphase-separated structure provides additional free volume and a more precise separation process, facilitating gas permeation. The soft segment contains ether bonds, which increase CO2 solubility while maintaining mechanical strength. The degree of microphase separation in polyether-polyurethane block copolymers can be regulated by adjusting the volume fraction of the monomers. Therefore, this microphase-separated structure can be used to form channels for enhanced CO2 transport. Researchers have proposed exploiting the differing compatibilities of the two PIs in a polymer blend membrane to cause phase separation, forming separate polymer phases. MOF particles, induced by the surface-attached PI, preferentially enter the same PI matrix phase, providing a fast pathway for them. Other researchers have proposed an ion-conducting membrane with a microphase-separated structure. Using one or more hydrophobic and hydrophilic polymer resins as raw materials, the membrane induces aggregation of the hydrophobic and hydrophilic phases during solvent evaporation, forming an ion-conducting membrane with a microphase-separated structure of hydrophobic and hydrophilic regions (CN107546398A). Some researchers have also proposed grafting non-polar SBS onto amorphous POEM, which can increase the CO2-philic area and improve the carbon dioxide separation performance without affecting the mechanical properties of the membrane.

[0004] Ionic liquids, especially those at room temperature, are ideal materials for carbon capture due to their low volatility and are commonly used in absorption applications. Imidazole-based ionic liquids, in particular, can enhance membrane separation performance when blended with polymers by leveraging the transfer-promoting effect of the imidazole groups. Mixing ionic liquids with polymers and exploiting the strong and weak interactions between the polymer segments and the ionic liquid to produce membrane materials is an effective method. Currently, some ionic liquid-polymer blend membranes have been used in gas separation applications.

[0005] Therefore, we propose using tunable block copolymers as templates. Due to the different hydrogen bonding interactions between the soft and hard segments of the block copolymer, the microphase separation structure of the block copolymer can be regulated by adjusting the polarity strength, molecular weight, and mass fraction of the soft segment, thereby forming a continuous morphology and constructing continuous nanoscale transmission channels to enhance gas diffusion selectivity. The introduction of ionic liquids with CO2-philic functional groups can functionalize the channels with CO2-philicity, improving CO2 solubility selectivity. Furthermore, due to the varying polarity of the ionic liquids, they interact strongly with the polymer chains, further regulating the microphase separation structure to form CO2-philic network channels. Furthermore, the presence of polar urethane and electron-donating -NH2 groups in the polyurethane membrane structure can enhance CO2 solubility through strong dipole-quadrupole interactions with CO2 molecules, thereby enhancing gas separation performance. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a method for constructing a mixed matrix membrane with continuous channels by regulating the microphase separation structure.

[0007] The technical solution of the present invention:

[0008] A method for constructing a mixed matrix membrane with continuous channels by regulating microphase separation structure, comprising the following steps:

[0009] (1) Preparation of regulated microphase separation structure of polyurethane block copolymer membranes

[0010] H1: Place the polyether polyol in a vacuum oven for dehydration, and maintain vacuum at 80-90°C for 3-6 hours;

[0011] H2: 5-30 parts by weight of polyether polyol, 2.5-15.01 parts of isocyanate, and 0.8-5 parts of ethyl isocyanate acrylate are added under a nitrogen atmosphere after heating, and 0.02-0.06 parts of catalyst dibutyltin dilaurate (DBTDL) are reacted to obtain a propenyl diisocyanate prepolymer;

[0012] H3: Continue to add 0.02-0.3 parts of 2-amino-5-fluorophenylboric acid / terbium complex, 0.872-5.229 parts of 1,6-hexanediamine, and 0.04-0.7 parts of 2,5-bis(4-aminophenoxy)biphenyl CAS No. 94148-67-1, and react with stirring under nitrogen atmosphere to obtain a polyurethane block copolymer;

[0013] H4: The polyurethane block copolymer is washed with 50 wt.% methanol and 50 wt.% aqueous solution to remove unreacted monomers or low molecular weight polymers, and then dried under vacuum at 60-70°C to obtain a polyurethane block copolymer.

[0014] The polyether polyol is one of PEG, PPG, PTMG and PTMEG, and has a molecular weight selected from one of 1000, 2000, 4000 and 6000, preferably PEG (2000).

[0015] The isocyanate is selected from one of IPDI, HDI, MDI and TDI, with a mass fraction of 20-60 wt.%, preferably MDI (45 wt.%).

[0016] The reaction temperature in H2 is 70-90°C, and the reaction time is 180-240 minutes.

[0017] The reaction temperature in H3 is 60-80°C and the reaction time is 100-150 minutes.

[0018] The preparation method of the 2-amino-5-fluorophenylboric acid / terbium complex is as follows:

[0019] 10-30 parts by weight of 2-amino-5-fluorophenylboric acid, 2-6 parts of terbium nitrate pentahydrate, and 160-300 parts of ethanol are mixed and heated for reaction. After the reaction is completed, the ethanol is distilled off, and the complex is then vacuum dried to obtain a 2-amino-5-fluorophenylboric acid / terbium complex.

[0020] The reaction temperature is 40-50° C. and the reaction time is 80-160 minutes.

[0021] (2) Preparation of polyurethane block copolymer membranes with imidazolium-based ionic liquids

[0022] S1: adding 0.3-3 parts of a polyether polyurethane block copolymer to 10-100 parts of an N,N-dimethylformamide solution to completely dissolve the block copolymer to obtain a block copolymer solution;

[0023] S2: Slowly add 0.0529-0.75 parts of ionic liquid to the block copolymer solution and stir magnetically to completely dissolve the ionic liquid to obtain a casting solution;

[0024] S3: Add the casting solution into a polytetrafluoroethylene culture dish, place it in a vacuum condition at 40-50° C. to remove the residual solvent, and obtain a mixed matrix membrane with continuous channels.

[0025] The ionic liquid is selected from one of [EMIM][PF6], [BMIM][PF6], [HMIM][PF6], [EMIM][TF2N], [BMIM][TF2N], [HMIM][TF2N], [EMIM][DCA], [BMIM][DCA], and [HMIM][DCA], preferably [HMIM][PF6].

[0026] Reaction mechanism

[0027] 1. Reaction of propylene diisocyanate prepolymer with 2-amino-5-fluorophenylboric acid / terbium complex:

[0028] The isocyanate groups (-NCO) in the propylene diisocyanate (ADI) prepolymer react with the amino groups (-NH2) in the 2-amino-5-fluorophenylboronic acid / terbium complex to form a urea bond (-NH-CO-NH-), which grafts the 2-amino-5-fluorophenylboronic acid / terbium complex onto the prepolymer.

[0029] 2. Reaction of propylene diisocyanate prepolymer and 2,5-bis(4-aminophenoxy)biphenyl:

[0030] The isocyanate groups in the ADI prepolymer undergo an addition reaction with the amino groups in 2,5-bis(4-aminophenoxy)biphenyl; urea bonds are also formed, introducing biphenyl groups into the prepolymer.

[0031] 3. Formation of block copolymers:

[0032] The products of the above two reactions are further polymerized to form block copolymers; the soft segments are composed of polyether segments, and the hard segments are composed of rigid structures (such as biphenyl groups) connected by urea bonds.

[0033] 4. Introduction of imidazolyl ionic liquids (ILs):

[0034] ILs are introduced into block copolymers by physical mixing or chemical bonding; ILs have high affinity and solubility for CO2 and can enhance the material's adsorption capacity for CO2.

[0035] Compared with the prior art, the present invention has the following significant effects:

[0036] 1. Regulating the degree of microphase separation:

[0037] By adjusting the ratio of soft and hard segments, the strength of the hydrogen bonding between the -NH groups in the hard segments and the -C=O groups and ester groups in the soft segments controls the extent of microphase separation. The soft segments are typically composed of flexible segments such as polyethers or polyesters, while the hard segments consist of urea bonds formed by the reaction of diisocyanates and small molecule chain extenders. The introduction of fluorophenylboronic acid / terbium complexes and rigid biphenyl groups can influence the ratio and distribution of the soft and hard segments, thereby adjusting the extent of microphase separation and forming continuous channels.

[0038] 2. The introduction of imidazolyl ionic liquids further modulates the microphase separation structure. Due to the varying polarity of the ionic liquids, they interact strongly and weakly with the polymer chains. Simultaneously, the microphase separation structure of the polyurethane block copolymer membrane forms a continuous structure. The introduction of ionic liquids with CO2-philic functional groups also functionalizes the channels with CO2-philicity, forming a CO2-philic network, further improving the material's CO2 adsorption and separation performance.

[0039] 3. Enhance the thermal stability of materials:

[0040] The fluorine atoms in the fluorophenylboric acid / terbium complex form stable coordination bonds with terbium, resulting in a highly thermally stable structure that maintains the material's structure and properties at high temperatures. The introduction of biphenyl groups increases the rigidity of the molecular chain, raising the material's glass transition temperature (Tg), further enhancing its thermal stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the AFM image of the ILs / PU film in the example.

[0042] Figure 2 These are AFM images of pure PU film and ILs / PU film in the examples, where (a) is PU-1 film, (b) is PU-2 film, (c) is 10wt.% ILs / PU-2 film, (d) is 15wt.% ILs / PU-2 film, and (e) is 20wt.% ILs / PU-2 film. DETAILED DESCRIPTION

[0043] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0044] Example 1

[0045] A method for constructing a mixed matrix membrane with continuous channels by regulating the microphase separation structure, wherein the operating steps are as follows:

[0046] (1) Preparation of regulated microphase separation structure of polyurethane block copolymer membranes

[0047] H1: Dehydrate the polyether polyol in a vacuum oven at 80°C for 3 hours;

[0048] H2: 5 g of polyether polyol PEG (2000), 2.5 g of 4,4-diphenylmethane diisocyanate (MDI), and 0.8 g of ethyl isocyanate acrylate were added to 0.02 g of dibutyltin dilaurate (DBTDL) as a catalyst under nitrogen atmosphere at 70°C and reacted for 180 min to obtain a propenyl diisocyanate prepolymer;

[0049] H3: 0.02 g of 2-amino-5-fluorophenylboric acid / terbium complex, 0.872 g of 1,6-hexanediamine, and 0.04 g of 2,5-bis(4-aminophenoxy)biphenyl (CAS No. 94148-67-1) were added, and the mixture was stirred at 60°C under a nitrogen atmosphere for 80 min to obtain a polyurethane block copolymer.

[0050] H4: The polyurethane block copolymer was washed with 50 wt.% methanol and 50 wt.% water solution, precipitated to remove unreacted monomers or low molecular weight polymers, and dried in vacuum at 60°C.

[0051] The preparation method of the 2-amino-5-fluorophenylboric acid / terbium complex is as follows:

[0052] 10 g of 2-amino-5-fluorophenylboric acid, 2 g of terbium nitrate pentahydrate, and 160 g of ethanol were mixed and reacted at 40° C. for 80 min. The ethanol was then distilled off and the mixture was vacuum dried to obtain a 2-amino-5-fluorophenylboric acid / terbium complex.

[0053] (2) Preparation of polyurethane block copolymer membranes with imidazolium-based ionic liquids

[0054] S1: Add 0.3 g of polyether polyurethane block copolymer to 10 g of N,N-dimethylformamide solution and dissolve it completely to obtain a block copolymer solution;

[0055] S2: Slowly add 0.0529 g of [HMIM][PF6] ionic liquid to the block copolymer solution and stir magnetically to completely dissolve the ionic liquid to obtain a casting solution;

[0056] S3: The casting solution was added to a polytetrafluoroethylene petri dish, dried at room temperature, and then placed in a 45°C vacuum oven to remove the residual solvent to obtain a membrane.

[0057] Example 2

[0058] A method for constructing a mixed matrix membrane with continuous channels by regulating the microphase separation structure, wherein the operating steps are as follows:

[0059] (1) Preparation of regulated microphase separation structure of polyurethane block copolymer membranes

[0060] H1: Dehydrate the polyether polyol in a vacuum oven at 80°C for 3 hours;

[0061] H2: 10 g of polyether polyol PEG (2000), 3.75 g of 4,4-diphenylmethane diisocyanate (MDI), and 1 g of ethyl isocyanate acrylate were added under nitrogen atmosphere at 70°C, and 0.03 g of catalyst dibutyltin dilaurate (DBTDL) was added. The reaction was continued for 200 min to obtain a propenyl diisocyanate prepolymer.

[0062] H3: 0.03 g of 2-amino-5-fluorophenylboric acid / terbium complex, 1.162 g of 1,6-hexanediamine, and 0.1 g of 2,5-bis(4-aminophenoxy)biphenyl (CAS No. 94148-67-1) were added, and the mixture was stirred at 60°C under a nitrogen atmosphere for 100 min to obtain a polyurethane block copolymer.

[0063] H4: The polyurethane block copolymer was washed with 50 wt.% methanol and 50 wt.% water solution, precipitated to remove unreacted monomers or low molecular weight polymers, and dried in vacuum at 60°C.

[0064] The preparation method of the 2-amino-5-fluorophenylboric acid / terbium complex is as follows:

[0065] 15 g of 2-amino-5-fluorophenylboric acid, 3 g of terbium nitrate pentahydrate, and 200 g of ethanol were mixed and reacted at 40° C. for 100 min. The ethanol was then distilled off and the mixture was vacuum dried to obtain a 2-amino-5-fluorophenylboric acid / terbium complex.

[0066] (2) Preparation of polyurethane block copolymer membranes with imidazolium-based ionic liquids

[0067] S1: Add 0.9 g of polyether polyurethane block copolymer to 30 g of N,N-dimethylformamide solution and dissolve it completely to obtain a block copolymer solution;

[0068] S2: Slowly add 0.122 g of [HMIM][PF6] ionic liquid to the block copolymer solution and stir magnetically to completely dissolve the ionic liquid to obtain a casting solution;

[0069] S3: The casting solution was added to a polytetrafluoroethylene petri dish, dried at room temperature, and then placed in a 45°C vacuum oven to remove the residual solvent to obtain a membrane.

[0070] Example 3

[0071] A method for constructing a mixed matrix membrane with continuous channels by regulating the microphase separation structure, wherein the operating steps are as follows:

[0072] (1) Preparation of regulated microphase separation structure of polyurethane block copolymer membranes

[0073] H1: Dehydrate the polyether polyol in a vacuum oven at 80°C for 4 hours;

[0074] H2: 15 g of polyether polyol PEG (2000), 7.5 g of 4,4-diphenylmethane diisocyanate (MDI), and 3 g of ethyl isocyanate acrylate were added to 0.04 g of dibutyltin dilaurate (DBTDL) as a catalyst under a nitrogen atmosphere at 75°C and reacted for 210 min to obtain a propenyl diisocyanate prepolymer;

[0075] H3: 0.1 g of 2-amino-5-fluorophenylboric acid / terbium complex, 2.615 g of 1,6-hexanediamine, and 0.2 g of 2,5-bis(4-aminophenoxy)biphenyl (CAS No. 94148-67-1) were added, and the mixture was stirred at 65°C under a nitrogen atmosphere for 110 min to obtain a polyurethane block copolymer.

[0076] H4: The polyurethane block copolymer was washed with 50 wt.% methanol and 50 wt.% water solution, precipitated to remove unreacted monomers or low molecular weight polymers, and dried in vacuum at 60°C.

[0077] The preparation method of the 2-amino-5-fluorophenylboric acid / terbium complex is as follows:

[0078] 20 g of 2-amino-5-fluorophenylboric acid, 4 g of terbium nitrate pentahydrate, and 240 g of ethanol were mixed, and the reaction temperature was 45° C. After the reaction for 120 min, the ethanol was distilled off, and then vacuum dried to obtain a 2-amino-5-fluorophenylboric acid / terbium complex.

[0079] (2) Preparation of polyurethane block copolymer membranes with imidazolium-based ionic liquids

[0080] S1: Add 1.2 g of polyether polyurethane block copolymer to 40 g of N,N-dimethylformamide solution and dissolve it completely to obtain a block copolymer solution;

[0081] S2: Slowly add 0.429 g of [HMIM][PF6] ionic liquid to the block copolymer solution and stir magnetically to completely dissolve the ionic liquid to obtain a casting solution;

[0082] S3: The casting solution was added to a polytetrafluoroethylene petri dish, dried at room temperature, and then placed in a 45°C vacuum oven to remove the residual solvent to obtain a membrane.

[0083] Example 4

[0084] A method for constructing a mixed matrix membrane with continuous channels by regulating the microphase separation structure, wherein the operating steps are as follows:

[0085] (1) Preparation of regulated microphase separation structure of polyurethane block copolymer membranes

[0086] H1: Dehydrate the polyether polyol in a vacuum oven at 85°C for 5 hours;

[0087] H2: 20 g of polyether polyol PEG (2000), 10.01 g of 4,4-diphenylmethane diisocyanate (MDI), and 4 g of ethyl isocyanate acrylate were reacted under nitrogen atmosphere at 85°C with 0.05 g of catalyst dibutyltin dilaurate (DBTDL) to obtain a propenyl diisocyanate prepolymer;

[0088] H3: 0.2 g of 2-amino-5-fluorophenylboric acid / terbium complex, 3.486 g of 1,6-hexanediamine, and 0.5 g of 2,5-bis(4-aminophenoxy)biphenyl (CAS No. 94148-67-1) were added, and the mixture was stirred at 75°C under a nitrogen atmosphere for 140 min to obtain a polyurethane block copolymer.

[0089] H4: The polyurethane block copolymer was washed with 50 wt.% methanol and 50 wt.% water solution, precipitated to remove unreacted monomers or low molecular weight polymers, and dried in vacuum at 60°C.

[0090] The preparation method of the 2-amino-5-fluorophenylboric acid / terbium complex is as follows:

[0091] 25 g of 2-amino-5-fluorophenylboric acid, 5 g of terbium nitrate pentahydrate, and 280 g of ethanol were mixed and reacted at 45° C. for 140 min. The ethanol was then distilled off and the mixture was vacuum dried to obtain a 2-amino-5-fluorophenylboric acid / terbium complex.

[0092] (2) Preparation of polyurethane block copolymer membranes with imidazolium-based ionic liquids

[0093] S1: Add 1.5 g of polyether polyurethane block copolymer to 50 g of N,N-dimethylformamide solution and dissolve it completely to obtain a block copolymer solution;

[0094] S2: Slowly add 0.591 g of [HMIM][PF6] ionic liquid to the block copolymer solution and stir magnetically to completely dissolve the ionic liquid to obtain a casting solution;

[0095] S3: The casting solution was added to a polytetrafluoroethylene petri dish, dried at room temperature, and then placed in a 45°C vacuum oven to remove the residual solvent to obtain a membrane.

[0096] Example 5

[0097] A method for constructing a mixed matrix membrane with continuous channels by regulating the microphase separation structure, wherein the operating steps are as follows:

[0098] (1) Preparation of regulated microphase separation structure of polyurethane block copolymer membranes

[0099] H1: Dehydrate the polyether polyol in a vacuum oven at 90°C for 6 hours;

[0100] H2: 30 g of polyether polyol PEG (2000), 15.01 g of 4,4-diphenylmethane diisocyanate (MDI), and 5 g of ethyl isocyanate acrylate were added to 0.06 g of dibutyltin dilaurate (DBTDL) as a catalyst under nitrogen atmosphere at 90°C and reacted for 240 min to obtain a propenyl diisocyanate prepolymer;

[0101] H3: 0.3 g of 2-amino-5-fluorophenylboric acid / terbium complex, 5.229 g of 1,6-hexanediamine, and 0.7 g of 2,5-bis(4-aminophenoxy)biphenyl (CAS No. 94148-67-1) were added, and the mixture was stirred at 80°C under a nitrogen atmosphere for 150 min to obtain a polyurethane block copolymer.

[0102] H4: The polyurethane block copolymer was washed with 50 wt.% methanol and 50 wt.% water solution, precipitated to remove unreacted monomers or low molecular weight polymers, and dried in vacuum at 60°C.

[0103] The preparation method of the 2-amino-5-fluorophenylboric acid / terbium complex is as follows:

[0104] 30 g of 2-amino-5-fluorophenylboric acid, 6 g of terbium nitrate pentahydrate, and 300 g of ethanol were mixed, and the reaction temperature was 50° C. After the reaction for 160 min, the ethanol was distilled off, and then vacuum dried to obtain a 2-amino-5-fluorophenylboric acid / terbium complex.

[0105] (2) Preparation of polyurethane block copolymer membranes with imidazolium-based ionic liquids

[0106] S1: Add 3 g of polyether polyurethane block copolymer to 100 g of N,N-dimethylformamide solution and dissolve it completely to obtain a block copolymer solution;

[0107] S2: Slowly add 0.75 g of [HMIM][PF6] ionic liquid to the block copolymer solution and stir magnetically to completely dissolve the ionic liquid to obtain a casting solution;

[0108] S3: The casting solution was added to a polytetrafluoroethylene petri dish, dried at room temperature, and then placed in a 50°C vacuum oven to remove the residual solvent to obtain a membrane.

[0109] Comparative Example 1

[0110] The same procedures as in Example 1 were followed except that the 2-amino-5-fluorophenylboric acid / terbium complex and 2,5-bis(4-aminophenoxy)biphenyl were not added.

[0111] Comparative Example 2

[0112] The other steps were the same as in Example 1 except that the 2-amino-5-fluorophenylboric acid / terbium complex was not added.

[0113] Comparative Example 3

[0114] The other steps were the same as in Example 1 except that 2,5-bis(4-aminophenoxy)biphenyl was not added.

[0115] Comparative Example 4

[0116] No ionic liquid was added, and the other procedures were the same as in Example 1.

[0117] Gas separation performance of the obtained membrane material at an operating pressure difference of 0.3 MPa and a temperature of 298.15 K

[0118] <![CDATA[CO2 Permeability (barrer)]]> <![CDATA[CO2 / N2 selectivity]]> Example 1 409.48 81.36 Example 2 418.65 83.22 Example 3 438.00 85.65 Example 4 458.76 88.42 Example 5 489.73 92.89 Comparative Example 1 399.82 79.17 Comparative Example 2 405.76 80.52 Comparative Example 3 406.55 80.41 Comparative Example 4 359.62 47.25

[0119] Figure 1 It is shown in the figure that as the hard segment content increases, more hydrogen bonds exist between the polyurethane-C=O and polyurethane-NH groups. The hydrogen bonds between the hard segment molecular segments can promote the same orientation of the molecules to a certain extent, and the molecular arrangement is directional, which is conducive to the phase separation of the soft segment and the hard segment to form a microphase separation structure. At the same time, the introduction of fluorophenylboric acid / terbium complex and rigid biphenyl group further affects the ratio and distribution of the soft and hard segments. The gas separation performance of Example 1 is compared with that of Example 2. It is obvious that when the hard segment is 45wt.%, the CO2 / N2 separation performance of Example 2 is better. Figure 2 It is shown that the introduction of imidazolyl ionic liquid further regulates the microphase separation structure, forms a CO2-philic network channel, and further improves the material's adsorption of CO2. The comparison of gas separation performance between Example 2, Example 3, Example 4 and Example 5 shows that the addition of [HMIM][PF6] ionic liquid further improves the CO2 / N2 separation performance.

[0120] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for constructing a mixed matrix membrane with continuous channels by regulating the microphase separation structure, characterized in that: Here are the steps: (1) Preparation of regulated microphase separation structure of polyurethane block copolymer membranes (1.1) Dehydrate the polyether polyol in a vacuum oven at 80-90°C for 3-6 hours; (1.2) 5-30 parts by weight of polyether polyol, 2.5-15.01 parts of isocyanate, and 0.8-5 parts of ethyl isocyanate acrylate are reacted under a nitrogen atmosphere, heated, and then 0.02-0.06 parts of dibutyltin dilaurate as a catalyst are added to obtain a propylene diisocyanate prepolymer; (1.3) Continue to add 0.02-0.3 parts of 2-amino-5-fluorophenylboric acid / terbium complex, 0.872-5.229 parts of 1,6-hexanediamine, and 0.04-0.7 parts of 2,5-bis(4-aminophenoxy)biphenyl, and react with stirring under nitrogen atmosphere to obtain a polyurethane block copolymer; (1.4) The polyurethane block copolymer is washed with a 50 wt.% methanol and 50 wt.% aqueous solution to remove unreacted monomers or low molecular weight polymers, and then dried under vacuum at 60-70°C to obtain a polyether polyurethane block copolymer. (2) Preparation of polyurethane block copolymer membranes with imidazolium-based ionic liquids (2.1) Add 0.3-3 parts of a polyether polyurethane block copolymer to 10-100 parts of an N,N-dimethylformamide solution and completely dissolve the polyether polyurethane block copolymer to obtain a block copolymer solution; (2.2) Slowly add 0.0529-0.75 parts of ionic liquid dropwise to the block copolymer solution and magnetically stir to completely dissolve the ionic liquid to obtain a casting solution; (2.3) Add the casting solution to a polytetrafluoroethylene culture dish and place it in a vacuum at 40-50°C to remove the residual solvent to obtain a mixed matrix membrane with continuous channels; The preparation method of the 2-amino-5-fluorophenylboric acid / terbium complex is as follows: 10-30 parts by weight of 2-amino-5-fluorophenylboric acid, 2-6 parts of terbium nitrate pentahydrate, and 160-300 parts of ethanol are mixed and heated for reaction. After the reaction is completed, the ethanol is distilled off, and the complex is then vacuum dried to obtain a 2-amino-5-fluorophenylboric acid / terbium complex.

2. The method according to claim 1, characterized in that The polyether polyol is one of PEG, PPG, PTMG, and PTMEG, and the molecular weight is one of 1000, 2000, 4000, and 6000.

3. The method according to claim 1, characterized in that The isocyanate is selected from one of IPDI, HDI, MDI and TDI, with a mass fraction of 20-60wt.%.

4. The method according to claim 1, wherein The reaction temperature in step (1.2) is 70-90°C, and the reaction time is 180-240 min.

5. The method according to claim 1, wherein The reaction temperature in step (1.3) is 60-80°C and the reaction time is 100-150 min.

6. The method according to claim 1, characterized in that The ionic liquid is selected from one of [EMIM][PF6], [BMIM][PF6], [HMIM][PF6], [EMIM][TF2N], [BMIM][TF2N], [HMIM][TF2N], [EMIM][DCA], [BMIM][DCA], and [HMIM][DCA].

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