Aperture-reconstructed polymer membrane material as well as preparation method and application thereof

Abstract

The invention discloses an aperture reconstruction polymer membrane material as well as a preparation method and application thereof, and belongs to the technical field of gas separation membranes. According to the invention, micromolecular dialkene, trialkene and tetraalkene are introduced into a glassy state / rubber state membrane material, then irradiation polymerization is carried out through an electron beam accelerator, in-situ formed poly-multi-olefin and a polymer chain are reconstructed, and a novel gas separation membrane is successfully constructed. According to the present invention, the limitation of the inherent pore channel of the traditional glassy state / rubber state membrane material is effectively solved, and the new gas separation pore channel is generated, such that the comprehensive performance of the gas separation membrane is significantly improved, and the breakthrough progress is particularly achieved in the helium gas separation and CO2 capture.

Description

Technical Field

[0001] This invention relates to the field of gas membrane separation technology, specifically to a pore size remodeling polymer membrane material, its preparation method, and its application. Background Technology

[0002] Porous polymer membrane materials play a crucial role in numerous industrial and scientific fields due to their unique physical structure and selective separation capabilities. These fields broadly encompass gas separation (such as hydrogen purification and carbon dioxide capture), water treatment (such as seawater desalination and wastewater purification), pervaporation, biomedicine, and energy storage. In all these applications, the pore size and distribution of the membrane are the core physical parameters determining its separation performance. Therefore, developing technologies that can precisely and stably control membrane pore size has always been a frontier and hot topic in membrane science research.

[0003] Currently, methods for controlling the pore size of polymer membranes mainly focus on the material synthesis and membrane preparation stages, and can be broadly categorized as follows: 1. Designing polymer chains with specific spatial conformations and rigidity through chemical synthesis. For example, introducing large-volume side groups or twisted chain structures to suppress the close packing of chain segments, thereby creating inherent micropores within the material. Although such materials can form sub-nanometer-scale channels, their pore size is essentially fixed after synthesis, making dynamic and reversible adjustment during use difficult; 2. Physically blending polymers with different properties, or adjusting the distance and free volume between chain segments through chemical crosslinking. While crosslinking can stabilize the membrane structure and improve its resistance to plasticization, it usually leads to pore size shrinkage and reduced permeation flux. Physical blending may face problems such as poor compatibility and phase separation after prolonged use, affecting the stability and lifespan of the membrane; 3. Performing heat treatment, solvent immersion, or surface chemical modification on the prepared membrane. For example, heat treatment can change the packing state of polymer chains, but this adjustment is often unidirectional and irreversible. While chemical modification can alter the properties of the pore surface, it is complex and has limited effectiveness in controlling the physical dimensions of the pores themselves. Summary of the Invention

[0004] The main objective of this invention is to propose a pore-reconstruction polymer membrane material, its preparation method, and its application.

[0005] To achieve the above objectives, this invention proposes a method for preparing a pore-reconstructed polymer membrane material, comprising the following steps: adding an olefin compound to a polymer to prepare a mixed matrix membrane, then encapsulating the mixed matrix membrane in a solvent, and then performing in-situ polymerization under electron beam irradiation to obtain a polymer membrane material with reconstructed pore size.

[0006] Preferably, the olefin compound is at least one of a diene compound, a triene compound, and a tetraene compound; the mass ratio of the olefin compound to the polymer is 1-5:5-9.

[0007] Preferably, the structural formula of the diene compound includes: .

[0008] Preferably, the structural formula of the triolefin compound includes: .

[0009] Preferably, the structural formula of the tetraolefin compound includes: .

[0010] Preferably, the polymer is a glassy polymer and / or a rubbery polymer.

[0011] Preferably, the glassy polymer is one of PIM-1, TB polyimide, polystyrene, polycarbonate, polysulfone, polyethersulfone, polyphenylene ether, and polyurethane.

[0012] A further preferred embodiment of the PIM-1 is as follows: .

[0013] More preferably, the polyimide has the following structural formula: .

[0014] Preferably, the rubbery polymer is one of polyvinylidene fluoride, polyvinyl alcohol, polyacrylamide, polyvinyl ether, polydimethylsiloxane, polyether, and polyamide block.

[0015] Preferably, the irradiation intensity is 40-120 kGy.

[0016] The present invention also provides the application of the above-mentioned pore size remodeling polymer membrane material in helium separation and CO2 capture.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a pore-reconstructed polymer membrane material, its preparation method, and its application. By introducing small-molecule dienes, trienes, and tetraenes into a glassy / rubbery membrane material, followed by irradiation polymerization in an electron beam accelerator, the in-situ formed polyolefins are reconstructed with the polymer chains, successfully constructing a novel gas separation membrane. This effectively solves the limitation of the inherent pores in traditional glassy / rubbery membrane materials, generating new gas separation channels and significantly improving the overall performance of the gas separation membrane, especially achieving breakthrough progress in helium separation and CO2 capture. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The infrared spectra of the PIM-1, PTT polymer, PTT-40, and PTT-40 RFIM samples of this invention are shown below. Figure 2 Thermogravimetric analysis spectra of PIM-1, PTT polymer, PTT-40, and PTT-40 RFIM samples of this invention; Figure 3 The X-ray photoelectron spectra of the PIM-1, PTT polymer, PTT-40, and PTT-40 RFIM samples of this invention are shown below. Figure 4 Two-dimensional wide-angle X-ray diffraction patterns of PIM-1, PTT polymer, PTT-40, and PTT-40 RFIM of the present invention.

[0020] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] To avoid unnecessary details, all items used in the following examples are commercially available products unless otherwise specified, all methods used are conventional methods unless otherwise specified, and all reagents used are commercial reagents and do not require purification treatment unless otherwise specified.

[0022] Instrument characterization: The instruments used were scanning electron microscope, attenuated total reflectance infrared spectroscopy, and atomic force microscope. 1 H NMR and 13CNMR was calibrated using tetramethylsilane (TMS) and deuterated chloroform (CDCl3) or deuterated dimethyl sulfoxide (DMSO-d6) signals. The thin-layer chromatography silica gel plates used in the experiments were commercially available HSGF254, and the silica gel used for column chromatography was 200-300 mesh.

[0023] The PIM-1 polymer in the embodiments and comparative examples of this invention was prepared according to conventional methods, specifically as follows: Under argon protection, stoichiometric amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirodiindane (TTSBI, 1.0 eq), 2,3,5,6-tetrafluoroterephthalonitrile (TFTPN, 1.0 eq), and anhydrous K2CO3 as a catalyst (molar amount 2.5 times the total molar amount of the monomers) were added to a reaction flask equipped with a mechanical stirrer, a condenser, and a thermometer. Subsequently, a mixed solvent of anhydrous NMP and toluene (v / v = 3:1) was added, and the reaction system was rapidly heated to 155°C and kept at that temperature for 4 hours. After the reaction was completed, the system was cooled to room temperature, and the reaction solution was poured into methanol to precipitate. The solid was collected by filtration and washed thoroughly with methanol and water sequentially. Subsequently, the crude product was placed in a 0.1 wt.% HCl aqueous solution and stirred to remove catalyst residue. After filtration, it was washed with deionized water until neutral and then rinsed with methanol. The resulting yellow PIM-1 polymer was vacuum dried at 80°C for 24 hours for later use.

[0024] Example 1 A method for preparing a pore-reconstruction polymer membrane material includes the following steps: 0.7 g of PIM-1 polymer powder was dissolved in 21 mL of chloroform, and then 0.3 g of 1,4-divinylbenzene (DVB) was added. The mixture was stirred until homogeneous to obtain a homogeneous solution. The solution was cast onto a clean, horizontal glass plate, and the solvent was allowed to evaporate slowly at room temperature for 48 hours to form a thin film. The formed DVB-30 mixed matrix film was peeled off from the substrate, dried to remove the solvent, and then immersed in 30 mL of deionized water. The film was then sealed in a polyethylene bag under vacuum to create an oxygen-free irradiation environment. Finally, the packaged sample was placed under an electron accelerator and treated with a total irradiation dose of 100 kGy at room temperature. After irradiation, the film was thoroughly soaked and cleaned for 48 hours, and finally dried under vacuum to obtain the pore size reconstruction polymer membrane material, denoted as DVB-30 RFIM.

[0025] Example 2 A method for preparing a pore size remodeling polymer membrane material is similar to that in Example 1, except that DVB is replaced with DAA, denoted as DAA-30 RFIM.

[0026] Example 3 A method for preparing a pore-reconstructed polymer membrane material is similar to that in Example 1, except that DVB is replaced with TAA, denoted as TAA-30 RFIM.

[0027] Example 4 A method for preparing a pore-reconstructed polymer membrane material is similar to that in Example 1, except that DVB is replaced with AHD, and it is denoted as PAHD-30 RFIM.

[0028] Example 5 A method for preparing a pore-reconstruction polymer membrane material is similar to that in Example 1, except that DVB is replaced with TPTT, denoted as TPTT-30 RFIM.

[0029] Example 6 A method for preparing a pore-reconstruction polymer membrane material is similar to that in Example 1, except that DVB is replaced with TTO, denoted as PTTO-30 RFIM.

[0030] Example 7 A method for preparing a pore-reconstruction polymer membrane material is similar to that in Example 1, except that DVB is replaced with PTT, denoted as PTT-30 RFIM.

[0031] Example 8 A method for preparing a pore-reconstruction polymer membrane material is similar to that in Example 1, except that DVB is replaced with TPT, denoted as TPT-30 RFIM.

[0032] Example 9 A method for preparing a pore-reconstruction polymer membrane material is similar to that in Example 1, except that DVB is replaced with PTL, denoted as PTL-30 RFIM.

[0033] Comparative Example 1 A method for preparing a polymer membrane material, similar to that in Example 1, except that no olefin compound is added, specifically includes the following steps: 0.7 g of PIM-1 polymer powder was dissolved in 21 mL of chloroform to obtain a homogeneous solution. This homogeneous solution was cast onto a clean, horizontal glass plate and allowed to stand at room temperature for 48 hours to allow the solvent to slowly evaporate and form a thin film. The resulting mixed matrix film was peeled off from the substrate, dried to remove the solvent, and then immersed in 30 mL of deionized water. The film was then sealed in a polyethylene bag under vacuum to create an oxygen-free irradiation environment. Finally, the sealed sample was placed under an electron accelerator and treated with a total irradiation dose of 100 kGy at room temperature. After irradiation, the sample was thoroughly soaked and cleaned for 48 hours, and finally vacuum dried to obtain the polymer film material, denoted as PIM-1-100 kGy.

[0034] Example 10 A method for preparing a pore-reconstruction polymer membrane material is similar to that in Example 7, except that the amount of PTT used is 10% of the total mass of PIM-1 polymer powder and olefin compound, denoted as PTT-10 mixed matrix membrane. The dried mixed matrix membrane is immersed in 30 mL of deionized water. The packaged sample is placed under an electron accelerator and treated with a total irradiation dose of 100 kGy at room temperature. After irradiation, it is thoroughly soaked and cleaned for 48 hours. Finally, it is vacuum dried to obtain the PTT-10 RFIM membrane material.

[0035] Example 11 A method for preparing a pore-reconstruction polymer membrane material is similar to that in Example 7, except that the amount of PTT used is 20% of the total mass of PIM-1 polymer powder and olefin compound, and is designated as PTT-20 RFIM membrane material.

[0036] Example 12 0.6 g of PIM-1 polymer powder was dissolved in 18 mL of chloroform, and then 0.4 g of PTT was added. The mixture was stirred until homogeneous to obtain a homogeneous solution. The solution was cast onto a clean, horizontal glass plate, and the solvent was allowed to evaporate slowly at room temperature for 48 hours to form a thin film. The formed PTT-40 mixed matrix film was peeled off from the substrate, dried to remove the solvent, and then immersed in 30 mL of deionized water. The film was then sealed in a polyethylene bag under vacuum to create an oxygen-free irradiation environment. Finally, the packaged sample was placed under an electron accelerator and treated with a total irradiation dose of 100 kGy at room temperature. After irradiation, the film was thoroughly soaked and cleaned for 48 hours, and finally dried under vacuum to obtain the pore size reconstruction polymer membrane material, denoted as PTT-40 RFIM membrane material.

[0037] Example 13 A method for preparing a pore-reconstruction polymer membrane material is similar to that in Example 7, except that the amount of PTT used is 50% of the total mass of PIM-1 polymer powder and olefin compound, and is referred to as PTT-50 RFIM membrane material.

[0038] Performance testing The polymer membrane materials obtained in Examples 1-13 and Comparative Example 1 were used for gas permeability coefficient and selective permeability tests at 35°C. The test gases were N2, CH4, He, H2, and CO2. The test results are shown in Table 1. Table 1. Performance test results of polymer membrane materials As can be seen from the experimental results in Table 1, different olefin compounds cause different changes in the properties of polymer membrane materials due to the formation of different network structures.

[0039] Example 14 The preparation method of pTT polymer includes the following steps: The pTT triene was prepared into a 2% methanol solution and irradiated in an accelerator with a total absorbed dose of 100 kGy to obtain a white solid. The solid was filtered, ultrasonically washed with methanol, and the pTT polymer was obtained, denoted as pTT polymer.

[0040] The infrared spectra of the PIM-1, PTT polymer, PTT-40, and PTT-40 RFIM samples of this invention are as follows: Figure 1 As shown in the figure, the characteristic absorption peak of the double bond is at 1404 cm⁻¹. -1 The double bond polymerized in the PTT-40 mixed matrix membrane after electron accelerator irradiation, and no double bond characteristic peaks appeared in the PTT-40 RFIM, proving that PTT undergoes in-situ polymerization in PIM-1 and forms a new membrane material with PIM-1.

[0041] Thermogravimetric analysis spectra of PIM-1, PTT polymer, PTT-40, and PTT-40 RFIM samples of this invention are as follows: Figure 2 As shown in the figure, the PTT-40 mixed matrix membrane has a low pyrolysis temperature, with the first degradation occurring at 171°C. o The initial degradation temperature of C, PTT-40RFIM occurred at 358°C. o C indicates that after irradiation, PTT polymerizes and integrates with the PIM-1 membrane material, thus increasing the degradation temperature.

[0042] The X-ray photoelectron spectra of the PIM-1, PTT polymer, PTT-40, and PTT-40 RFIM samples of this invention are as follows: Figure 3 As shown in the figure, the double-bonded carbon has a binding energy of 285.8 eV. Due to the terminal double-bonded carbon being located in the PTT-40 mixed matrix film, the binding energy of the carbon shifts to the left. After irradiation, the double bond polymerizes, and the double-bonded carbon's binding energy of 285.8 eV remains consistent with that of the PTT polymer. Furthermore, ester functional groups are present in PTT polymer, PTT-40, and PTT-40 RFIM.

[0043] This invention uses two-dimensional wide-angle X-ray diffraction patterns as shown in the figure. Figure 4 As shown, the irradiated PTT-40 RFIM contains the cyclic band gap of PIM-1 and PTT polymer, proving that the small molecule triolefin polymerizes into a polymer after irradiation and is woven together with the PIM-1 membrane.

[0044] The above characterization results all demonstrate that small molecule olefins polymerize within the membrane, becoming an integral part of the membrane, thereby reconstructing the pores within the membrane and further improving the gas separation performance of the membrane material.

[0045] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present 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 patent protection scope of the present invention.

Claims

1. A method for preparing a pore size remodeling polymer membrane material, characterized in that, The process includes the following steps: adding an olefin compound to a polymer to prepare a mixed matrix membrane, then encapsulating the mixed matrix membrane in a solvent, and then performing in-situ polymerization under electron beam irradiation to obtain a pore size remodeling polymer membrane material.

2. The preparation method according to claim 1, characterized in that: The olefin compound is at least one of a diene compound, a triene compound, and a tetraene compound.

3. The preparation method according to claim 2, characterized in that, The structural formula of the diene compound includes: 。 4. The preparation method according to claim 2, characterized in that, The structural formula of the triolefin compound includes: 。 5. The preparation method according to claim 2, characterized in that, The structural formula of the tetraolefin compound includes: 。 6. The preparation method according to claim 1, characterized in that: The polymer is a glassy polymer and / or a rubbery polymer.

7. The preparation method according to claim 6, characterized in that: The glassy polymer is one of PIM-1, TB polyimide, polystyrene, polycarbonate, polysulfone, polyethersulfone, polyphenylene ether, and polyurethane.

8. The preparation method according to claim 7, characterized in that, The structural formula of PIM-1 is as follows: 。 9. A pore size remodeling polymer membrane material, characterized in that: It is prepared by the preparation method described in any one of claims 1-8.

10. The application of the polymer membrane material of claim 9 in helium separation and CO2 capture.

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