Method for efficiently preparing ionic super-crosslinked polymer by mechanochemical method, product and application thereof

Abstract

The invention discloses a method for efficiently preparing an ionic super-crosslinked polymer by a mechanochemical method as well as a product and application of the ionic super-crosslinked polymer, and belongs to the technical field of polymer material preparation. The preparation method comprises the following steps: adding a nitrogen-containing monomer, a cross-linking agent and a catalyst into a good solvent to obtain a reaction solution; carrying out planetary ball milling treatment on the reaction liquid, and carrying out a Friedel-Crafts alkylation reaction; and after the reaction is completed, recovering and purifying the product to obtain the ionic super-crosslinked polymer. The ionic super-crosslinked polymer prepared by the preparation method disclosed by the invention has a highly crosslinked and abundant pore structure, and meanwhile, the ionic super-crosslinked polymer has the performance advantages of good adsorption performance, excellent chemical stability and high thermal stability. The synthetic method of the ionic super-crosslinked polymer provided by the invention is efficient, energy-saving and environment-friendly, the product quality is high, and the method has wide popularization and application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material preparation, and in particular to a method for efficiently preparing ionic hypercrosslinked polymers by mechanochemistry, as well as products and applications thereof. Background Art

[0002] Hypercrosslinked polymers are a series of permanently microporous polymer materials. Initially discovered by Davankov, they have gradually received increasing attention in recent years. Hypercrosslinked polymers have significant advantages such as diverse synthesis methods, easy functionalization, high surface area, low-cost reagents, and safe operating conditions. Reasonably selecting monomers, crosslinkers of appropriate length, and optimizing reaction conditions can prepare polymer skeletons with adjustable porous topologies. Introducing other chemical functional groups later can further enhance their properties, thus enabling applications in specific scenarios.

[0003] For example, the Chinese invention patent with the publication number CN119456028A discloses an N-phenylphenothiazine hypercrosslinked polymer catalyst and its preparation method and application. This application uses the Friedel-Crafts reaction to dissolve N-phenylphenothiazine (Ⅰ), dimethylol formaldehyde (Ⅱ), and Lewis acid in a solvent, stir and react at 60~120 °C for 12~36 h, cool and filter, then extract with a Soxhlet extractor for 12~24 h, cool and filter again. After drying the obtained solid, the N-phenylphenothiazine hypercrosslinked polymer catalyst is obtained. However, the overall reaction process of this hypercrosslinked polymer takes too long, which easily causes problems such as an increase in side reactions, an increase in production costs, and limited production efficiency.

[0004] The Chinese invention patent with the publication number CN115572371A provides a preparation method of an ionic porous polymer material and its application in essential oil adsorption and de-terpenation. This scheme reacts monomers and crosslinkers in a quaternization solvent, removes the quaternization solvent by rotary evaporation and vacuum drying to obtain a quaternized product; reacts the quaternized product with a Lewis acid catalyst in a Friedel-Crafts reaction solvent, washes the reaction product, and further performs Soxhlet extraction. After drying, an ionic porous polymer material with an anion of Cl - or Br - is obtained. The above solvent thermal method for preparing polymers has limitations such as high energy consumption, a cumbersome preparation process, a long operation time, and strict equipment requirements, and has safety problems.

[0005] In addition, in a Chinese invention patent with the publication number CN117258568A, an ionic hypercrosslinked polymer membrane, a preparation method thereof, and an application thereof are provided. A novel ionic hypercrosslinked polymer membrane with a novel structure is obtained by using tris(4-imidazol-1-ylphenyl)amine and 1,4-bis(bromomethyl)benzene through Friedel-Crafts alkylation reaction and quaternization reaction with ferric trichloride as a catalyst. However, the process of preparing the above-mentioned ionic polymer is cumbersome, with a large solvent consumption and a long operation time, making it difficult to be mass-produced and applied in industry.

[0006] Mechanochemistry is a novel green synthesis strategy that drives solid-state chemical reactions through mechanical energy. In the chemical reactions driven by mechanical force, it mainly relies on converting mechanical force into chemical energy to overcome the activation energy barrier of the reaction, enabling covalent bonds to form between monomer molecules. The instantaneous high temperature generated during mechanical friction can accelerate the reaction kinetics. Mechanical force will force the monomers and crosslinking agents to be in close contact, thereby improving the reaction efficiency and shortening the reaction time. Compared with the methods of preparing hypercrosslinked polymers by solvothermal method and photoinitiation method, mechanochemistry has the advantages of being green, environmentally friendly, and fast, and is suitable for large-scale production and environmental remediation.

[0007] For example, a Chinese invention patent with the publication number CN113651981A discloses a method for preparing heavy organic matter-based polymers by mechanochemistry. This process has the characteristics of short reaction time for preparing polymers, no need for solvents during the reaction process, low cost, environmental protection, energy saving, simple operation, and easy industrialization. However, there are no heteroatoms in its polymers, which limits their application in the fields of adsorption and catalysis.

[0008] Using mechanochemistry to directly introduce heteroatoms into the preparation of hypercrosslinked polymers to form ionic hypercrosslinked polymers faces various challenges in actual production. Among them, the introduction of heteroatoms will change the physical and chemical properties of the polymers, affecting the formation of crosslinking density and pore structure. While mechanical energy promotes the above reactions, it is easy to trigger the self-polymerization or over-crosslinking of nitrogen-containing monomers, destroying the pore structure. Moreover, although the polymers synthesized by traditional mechanochemistry have a high degree of crosslinking, they have a low porosity and lack ionic active sites. Directly introducing heteroatoms easily causes pore blockage, and additional post-modification steps are often required to form ionic sites, increasing the complexity of the process.

[0009] Currently, there are no research reports on using mechanochemistry to treat ionic polymers that urgently need resource utilization. Using mechanochemistry to simply, quickly, and environmentally friendly synthesize high-value-added ionic hypercrosslinked polymers and overcome the above-mentioned technical obstacles in the preparation is of great significance for expanding the application of ionic hypercrosslinked polymers. Summary of the Invention

[0010] In view of the above-mentioned defects of the prior art, in the first aspect of the present invention, there is provided a method for preparing an ionic hypercrosslinked polymer with short reaction time, mild reaction conditions, environmental protection, energy conservation, simple operation and easy industrialization, comprising the following steps: Adding a nitrogen-containing monomer, a crosslinking agent and a catalyst to a good solvent to obtain a reaction solution; The nitrogen-containing monomer is a benzyl-substituted nitrogen heterocyclic compound, including one of 1-benzylimidazole, 1-benzylpiperidine, 2-benzylpyrrole, and 2-benzylpyrazine; The crosslinking agent is a halogen-containing crosslinking agent, including at least one of 4,4-biphenyldichlorobenzyl, 1,4-p-dichlorobenzyl, and 9,10-bis(chloromethyl)anthracene; The catalyst is a Lewis acid-type metal chloride, including at least one of aluminum trichloride, iron trichloride, zinc chloride, and tin chloride; The reaction solution is subjected to a planetary ball milling treatment to carry out a Friedel-Crafts alkylation reaction; after the reaction is completed, the product is recovered and purified to obtain an ionic hypercrosslinked polymer.

[0011] Preferably, the good solvent includes at least one of chloroform, dichloromethane, and dichloroethane.

[0012] Preferably, the concentration of the nitrogen-containing monomer in the reaction solution is 0.01-0.05 g / mL.

[0013] Preferably, the mass ratio of the nitrogen-containing monomer to the crosslinking agent is 1:1-10; the mass ratio of the nitrogen-containing monomer to the catalyst is 1:0.1-5.

[0014] Preferably, in the planetary ball milling treatment, the material of the grinding medium balls includes one of alumina, agate, zirconia, polytetrafluoroethylene, tungsten carbide, and stainless steel.

[0015] Preferably, in the planetary ball milling treatment, the size of the grinding medium balls includes at least one of 5 mm, 10 mm, and 15 mm.

[0016] Preferably, the rotation speed of the planetary ball milling treatment is 100-500 rpm; the treatment duration is 10-60 min.

[0017] In the present invention, the selection of the planetary ball milling method is not a simple process replacement, but rather, in view of the synthesis requirements of ionic hypercrosslinked polymers (HCPs), through its unique working principle and parameter design, it solves the key technical problems that cannot be achieved by other mechanochemical methods, thereby having a decisive impact on the product structure, performance, and process efficiency.

[0018] The principle of planetary ball milling treatment is that through the superposition of the rotation and revolution of the grinding pot, the grinding balls collide and rub at high frequency under the action of centrifugal force, generating an extremely high local energy density (the temperature instantaneously rises above 200 °C). The Friedel-Crafts alkylation reaction of nitrogen-containing monomers and cross-linking agents requires a relatively high activation energy. The high-energy impact of planetary ball milling can directly break chemical bonds and promote the start of the reaction. However, the energy density of ordinary vibration mills is insufficient (only about 10 GPa), the reaction efficiency is low, the flexibility of energy input is limited, and it is difficult to match the reaction kinetics requirements of nitrogen-containing monomers (such as staged energy input). By adjusting the rotation speed (such as 100 - 500 rpm) and the grinding ball size (such as a mixture of 5 mm, 10 mm, and 15 mm), planetary ball milling can precisely control the intensity of energy input, avoiding self-polymerization or structural damage of nitrogen-containing monomers due to mechanical force overload. The catalyst is evenly dispersed in the reaction system under the shearing action of planetary ball milling, avoiding side reactions caused by too high local concentration.

[0019] The co-design of raw material selection and planetary ball milling process parameters not only relies on the conventional effects of mechanical friction (such as instantaneous high temperature and contact promotion), but also achieves breakthroughs in the structure and performance of the product through the following unique mechanisms, which are significantly different from the prior art: (1) Staged energy control; (2) Using mixed-size grinding balls (such as a mixture of 5 mm, 10 mm, and 15 mm) combined with the complex motion trajectory of planetary ball milling to generate a gradient energy field. The preparation time of the mixed balls is shorter than that of single balls, and the product is uniform. The planetary ball milling method quickly completes the cross-linking reaction through short-time high-intensity energy input, significantly reducing the self-polymerization tendency of nitrogen-containing monomers.

[0020] Preferably, after the reaction is completed, a poor solvent is used to transfer the product, and after filtration, washing, extraction, and drying, the recovery and purification of the product are completed to obtain an ionic hypercrosslinked polymer.

[0021] More preferably, the poor solvent includes at least one of water, methanol, ethanol, acetone, and ethyl acetate.

[0022] More preferably, the drying temperature is 60 - 200 °C, and the duration is 8 - 24 h.

[0023] In the second aspect of the present invention, there is provided an ionic hypercrosslinked polymer having a hierarchical pore structure, a high specific surface area, and excellent adsorption activity, which is prepared by the method of the first aspect of the present invention.

[0024] In the third aspect of the present invention, there is provided an application of the ionic hypercrosslinked polymer of the second aspect of the present invention, including being used as an adsorption material for carbon dioxide adsorption treatment.

[0025] Ordinary polymers prepared by mechanochemistry only have a single function, while ionic hypercrosslinked polymers can simultaneously achieve the dual functions of carbon dioxide adsorption and catalysis (such as adsorbing carbon dioxide and catalyzing the formation of substances such as carbonates).

[0026] Based on the above technical solutions, the design concept and principle of the present invention are as follows: Based on the mechanochemistry method, the present invention realizes in-situ ionization in one step through planetary ball milling treatment without post-modification. Compared with the traditional "synthesis first and then modification" process, it significantly reduces energy consumption and waste emissions. At the same time, the ionic polymers produced by the mechanochemistry method have a high yield and are suitable for large-scale industrial applications compared with the ordinary solvent method preparation process.

[0027] While mechanical energy (including ordinary ball milling processes, etc.) promotes the reaction, it may cause self-polymerization or over-crosslinking of nitrogen-containing monomers, destroying the pore structure. Simply increasing the mechanical force intensity will result in uneven distribution of ionic functional groups. The present invention adopts a staged ball milling process or a positive and negative grinding process. Planetary ball milling promotes the preliminary crosslinking of monomers and crosslinking agents at low rotation speeds; at high rotation speeds, high-intensity mechanical forces are used to directionally open the local crosslinked network to form hierarchical pores.

[0028] The present invention uses a designed type of nitrogen-containing monomer. The introduction of nitrogen atoms is used to provide ionic sites and, through steric hindrance effects and the shearing action of mechanical forces in the reaction, jointly regulate the crosslinked network to form a high-porosity and hierarchical pore structure, which is difficult to achieve by traditional thermodynamically driven methods. In the prior art, the mechanochemistry method may lead to over-crosslinking or structural collapse. Therefore, the nitrogen-containing monomer of the present invention alleviates this problem through electrostatic repulsion to achieve a balance between high crosslinking degree and high specific surface area.

[0029] Nitrogen-free polymers synthesized by traditional mechanochemistry methods have a high crosslinking degree, but low porosity and lack of ionic active sites; directly introducing nitrogen atoms easily causes pore blockage. The present invention designs to use mechanically induced local high temperature to promote the quaternization reaction of nitrogen-containing groups and crosslinking agents to directly fix ionic sites on the backbone, avoiding the post-modification step.

[0030] When introducing heteroatoms in the present invention, a key technical obstacle needs to be overcome, that is, nitrogen-containing monomers have Lewis basicity and are prone to strong coordination with traditional Friedel-Crafts catalysts (such as FeCl3, AlCl3), which may cause catalyst deactivation. In the catalyst design and selection of the present invention, when FeCl3 and ZnCl2 are compounded, the weak coordination of Zn 2+ with nitrogen can be utilized to reduce catalyst poisoning.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects: The present invention provides a method for preparing an ionic hypercrosslinked polymer, which has the advantages of short reaction time, mild reaction conditions, environmental protection, energy saving, simple operation and easy industrialization.

[0032] The present invention provides an ionic hypercrosslinked polymer, which has a hierarchical pore structure, a high specific surface area and contains nitrogen elements. The heteroatom nitrogen introduced into the polymer framework will enhance the affinity for CO2 under Lewis acid-base interaction or dipole-quadrupole interaction, and combined with the hierarchical pore structure to jointly improve the adsorption effect of carbon dioxide.

[0033] The present invention provides an application of an ionic hypercrosslinked polymer, which has excellent adsorption performance for carbon dioxide, provides a new way for the high-value utilization of ionic hypercrosslinked polymers, and has good popularization prospects and application value. Description of the Drawings

[0034] Figure 1 It is the nitrogen adsorption and desorption curve graph of the ionic hypercrosslinked polymer prepared in Example 4; Figure 2 It is the scanning electron microscope image of the ionic hypercrosslinked polymer prepared in Example 4; Figure 3 It is the infrared spectrum of the ionic hypercrosslinked polymer prepared in Example 4; Figure 4 It is the curve graph of the ionic hypercrosslinked polymer prepared in Example 4 adsorbing carbon dioxide; Figure 5 It is the curve graph of the ionic hypercrosslinked polymer prepared in Example 1 adsorbing carbon dioxide. Detailed Embodiments

[0035] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. The experimental methods without specific conditions in the following examples are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0036] Example 1 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.848 g of 1-benzylimidazole, 5.753 g of 4,4-biphenyldichlorobenzyl, 8 g of anhydrous ferric chloride, 2 g of anhydrous zinc chloride, and 100 mL of dichloroethane and put them into a 300 mL grinding jar. Then add 60 zirconia grinding balls with a diameter of 5 mm, 20 with a diameter of 10 mm, and 10 with a diameter of 15 mm. Ball mill at 100 rpm for 15 min, then ball mill at 200 rpm for 15 min. Transfer the product with ethanol, filter, wash the product with methanol and extract for 12 h, and then rotary evaporate at 60 °C for 8 h to obtain the ionic hypercrosslinked polymer.

[0037] Example 2 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.848 g of 1-benzylimidazole, 3.9028 g of 1,4-dichlorobenzyl, 6 g of anhydrous ferric chloride, and 100 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 60 zirconia grinding balls with a diameter of 5 mm, 20 with a diameter of 10 mm, and 10 with a diameter of 15 mm. Ball mill at 100 rpm for 30 min. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain the ionic hypercrosslinked polymer.

[0038] Example 3 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.848 g of 1-benzylimidazole, 3.9028 g of 1,4-dichlorobenzyl, 8 g of anhydrous ferric chloride, and 80 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 60 zirconia grinding balls with a diameter of 5 mm, 20 with a diameter of 10 mm, and 10 with a diameter of 15 mm. Ball mill at 100 rpm for 30 min. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain the ionic hypercrosslinked polymer.

[0039] Example 4 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.848 g of 1-benzylimidazole, 5.753 g of 4,4-biphenyldichlorobenzyl, 8 g of anhydrous ferric chloride, and 80 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 60 zirconia grinding balls with a diameter of 5 mm, 20 with a diameter of 10 mm, and 10 with a diameter of 15 mm. Ball mill at 100 rpm for 30 min. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain the ionic hypercrosslinked polymer.

[0040] Example 5 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.848 g of 1-benzylimidazole, 3.9028 g of 1,4-dichlorobenzyl, 8 g of anhydrous ferric chloride, and 80 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 40 zirconia grinding balls with a diameter of 5 mm, 30 with a diameter of 10 mm, and 20 with a diameter of 15 mm. Ball mill for 30 min at 100 rpm. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain an ionic hypercrosslinked polymer.

[0041] Example 6 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.402 g of 1-benzylpiperidine, 3.9028 g of 1,4-dichlorobenzyl, 6 g of anhydrous ferric chloride, and 100 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 60 zirconia grinding balls with a diameter of 5 mm, 20 with a diameter of 10 mm, and 10 with a diameter of 15 mm. Ball mill for 30 min at 100 rpm. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain an ionic hypercrosslinked polymer.

[0042] Example 7 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.402 g of 1-benzylpiperidine, 5.753 g of 4,4-biphenyldichloride, 8 g of anhydrous ferric chloride, and 80 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 40 zirconia grinding balls with a diameter of 5 mm, 30 with a diameter of 10 mm, and 20 with a diameter of 15 mm. Ball mill for 30 min at 100 rpm. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain an ionic hypercrosslinked polymer.

[0043] Example 8 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.926 g of 2-benzylpyridine, 5.753 g of 4,4-biphenyldichloride, 6 g of anhydrous ferric chloride, and 80 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 60 zirconia grinding balls with a diameter of 5 mm, 20 with a diameter of 10 mm, and 10 with a diameter of 15 mm. Ball mill for 30 min at 100 rpm. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain an ionic hypercrosslinked polymer.

[0044] Example 9 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.926 g of 2-benzylpyridine, 3.9028 g of 1,4-dichlorobenzyl, 6 g of anhydrous ferric chloride, and 80 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 60 zirconia grinding balls with a diameter of 5 mm, 20 with a diameter of 10 mm, and 10 with a diameter of 15 mm. Ball mill at 100 rpm for 30 min. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain the ionic hypercrosslinked polymer.

[0045] Example 10 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.848 g of 1-benzylimidazole, 3.9028 g of 1,4-dichlorobenzyl, 6 g of anhydrous ferric chloride, and 80 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 60 alumina grinding balls with a diameter of 5 mm, 20 with a diameter of 10 mm, and 10 with a diameter of 15 mm. Ball mill at 100 rpm for 30 min. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain the ionic hypercrosslinked polymer.

[0046] Example 11 An ionic hypercrosslinked polymer is prepared by the following method: Take 3.848 g of 1-benzylimidazole, 3.9028 g of 1,4-dichlorobenzyl, 6 g of anhydrous ferric chloride, and 80 mL of dichloroethane and place them in a 300 mL grinding jar. Then add 60 zirconia grinding balls with a diameter of 5 mm, 20 with a diameter of 10 mm, and 10 with a diameter of 15 mm. Ball mill at 200 rpm for 30 min. Transfer the product with ethanol, and after filtration, wash and extract the product with methanol for 12 h. Then rotary evaporate at 60 °C for 8 h to obtain the ionic hypercrosslinked polymer.

[0047] Example 12 In this example, the prepared ionic hypercrosslinked polymer is used as a physical adsorbent and applied to the adsorption of carbon dioxide. And the adsorption performance of the ionic hypercrosslinked polymer is tested.

[0048] The N2 adsorption - desorption experiment was carried out using a Micromeritics (ASAP 2460) specific surface area and porosity analyzer. The specific surface area was calculated by the Brunauer - Emmett - Teller (BET) method. The BET surface area (SBET) was measured at a relative pressure (P / P0) of 0.025 - 0.25. The specific surface area test results of the ionic hypercrosslinked polymers in Examples 1 - 8 are shown in Table 1. Taking Example 4 with the largest specific surface area as an example, the nitrogen adsorption - desorption curve of the obtained ionic hypercrosslinked polymer is shown in Figure 1 .

[0049] Table 1: Specific surface area test results of ionic hypercrosslinked polymers

[0050] From the test results in Table 1, it can be seen that the ionic hypercrosslinked polymers prepared in the examples have a relatively high specific surface area, creating good conditions for carbon dioxide adsorption. Among them, in Example 4, the reactants prepared by mechanochemical method from 1 - benzylimidazole and 4,4 - biphenylchlorobenzyl have a higher specific surface area compared to the products obtained from the reaction of other nitrogen - containing monomers and crosslinking agents.

[0051] It can be seen from Figure 1 that the N2 adsorption / desorption isotherm results of the ionic hypercrosslinked polymer in Example 4 show that the curve is a type Ⅳ isotherm. In the low - pressure section (P / P0 < 0.05), the nitrogen adsorption amount increases rapidly, indicating that the ionic hypercrosslinked polymer has a microporous structure. An obvious hysteresis loop appears in the middle - pressure section, indicating the presence of mesopores. At higher pressures (P / P0 > 0.90), the polymer adsorption / desorption isotherm rises sharply, and the polymer has a small amount of macroporous structure, having a hierarchical pore structure. Combining the results in Table 1, its specific surface area reaches 1519 m 2 / g.

[0052] The microscopic morphology of the porous adsorbent in Example 4 was observed using a field - emission scanning electron microscope (model NovaNano - 450, FEI Company, USA). Before observation, it was vacuum - gold - plated for 300 s and observed at an acceleration voltage of 3 kV. The field - emission scanning electron microscope images are shown in Figure 2 . Figure 2 It shows that the ionic hypercrosslinked polymer is formed by particle packing to form an open and ordered 3D pore structure, which is beneficial to carbon dioxide adsorption.

[0053] Figure 3 is the infrared spectrum of the ionic hypercrosslinked polymer prepared in Example 4; an obvious C - N stretching vibration peak appears at 1487 cm -1 . Due to the nucleophilic substitution reaction, this vibration should come from the N - alkyl heterocycle in imidazoline. In addition, at 1607 cm -1The absorption vibration peak at this wavenumber can be attributed to the imidazole ring, and the C-H stretching at 2919 cm -1 is from the methylene (-CH2-) cross-linking bridge. These test results indicate the successful preparation of the ionic hypercrosslinked polymer.

[0054] The carbon dioxide adsorption performance of the ionic hypercrosslinked polymers obtained in Examples 1 and 4 was measured by a SSA-7000 pore size and specific surface area analyzer using the static volumetric method. When testing, an appropriate amount of sample was weighed and placed in a sample tube. First, it was preheated on a vacuum degassing station, and then placed on the SSA-7000 pore size and specific surface area analyzer for carbon dioxide adsorption performance testing. The CO2 adsorption isotherm of the sample was measured using the SSA-7000 pore size and specific surface area analyzer. Figure 4 and Figure 5 are the isotherms of the sample's CO2 adsorption at 273 K. It can be seen from Figure 5 that the ionic hypercrosslinked polymer of Example 1 has excellent adsorption performance for CO2.

[0055] Combined with the design principle of the present invention, during the preparation of the ionic hypercrosslinked polymer, the multi-directional shear force of planetary ball milling enables the reactants to achieve molecular-level dispersion, overcomes the diffusion limitation of the traditional thermal method, and improves the crosslinking uniformity. The staged rotation speed of planetary ball milling, at a low rotation speed in the first stage, the low energy input promotes the preliminary crosslinking of the monomer and the crosslinking agent to form a stable microporous framework (pore size < 2 nm), avoiding the structural collapse caused by high-energy impact; at a high rotation speed in the second stage, the short-term high-intensity energy input directionally opens the local crosslinking network, introduces mesoporous channels (pore size 2 - 5 nm) through mechanical shear force, and at the same time the locally high temperature induced by mechanical force promotes the direct quaternization reaction of the nitrogen-containing group and the crosslinking agent, without post-modification, avoiding the destruction of the pore structure. For the size ratio of grinding balls (such as a mixture of 5 mm, 10 mm, and 15 mm), small-sized balls provide high-frequency shear force to achieve nanoscale dispersion of the catalyst and the monomer; large-sized balls generate high impact energy to activate the inert C-N bond and accelerate the Friedel-Crafts alkylation. The reaction time for the preparation with a single ball will be longer and the surface area will be lower. The type selection of the catalyst can play a coordination competition protection mechanism when needed. Zn 2+ preferably has a weak coordination with the nitrogen-containing monomer, reducing the poisoning of the active sites of FeCl3 and maintaining the catalytic efficiency.

[0056] In summary, the ionic hypercrosslinked polymer prepared by the present invention has a highly crosslinked and rich pore structure. At the same time, this ionic hypercrosslinked polymer has performance advantages such as good adsorption performance, excellent chemical stability, and high thermal stability. The synthesis method of the ionic hypercrosslinked polymer provided by the present invention is efficient, energy-saving and environmentally friendly, and the product quality is high, with broad prospects for promotion and application.

[0057] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art in this technical field based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. A method for preparing an ionic hypercrosslinked polymer, characterized in that: The steps include: Adding nitrogen-containing monomers, crosslinking agents, and catalysts to a good solvent to obtain a reaction solution; The nitrogen-containing monomer is a benzyl-substituted nitrogen heterocyclic compound, including one of 1-benzylimidazole, 1-benzylpiperidine, 2-benzylpyrrole, and 2-benzylpyrazine; The crosslinking agent is a halogen-containing crosslinking agent, including at least one of 4,4-biphenyldichlorobenzyl, 1,4-dichlorobenzyl, and 9,10-bis(chloromethyl)anthracene; The catalyst is a Lewis acid type metal chloride, including at least one of aluminum chloride, ferric chloride, zinc chloride and tin chloride; The reaction solution is subjected to planetary ball milling for Friedel-Crafts alkylation reaction; after the reaction is completed, the product is recovered and purified to obtain an ionic hyper-crosslinked polymer.

2. The method for preparing an ionic hypercrosslinked polymer according to claim 1, characterized in that: The good solvent includes at least one of chloroform, dichloromethane and dichloroethane.

3. The method for preparing an ionic hyper-crosslinked polymer according to claim 1, characterized in that: The concentration of the nitrogen-containing monomer in the reaction solution is 0.01-0.05 g / mL; the mass ratio of the nitrogen-containing monomer to the cross-linking agent is 1:1-10; and the mass ratio of the nitrogen-containing monomer to the catalyst is 1:0.1-5.

4. The method for preparing an ionic hypercrosslinked polymer according to claim 1, characterized in that: In the planetary ball milling process, the material of the grinding medium ball includes one of aluminum oxide, agate, zirconium oxide, polytetrafluoroethylene, tungsten carbide and stainless steel.

5. The method for preparing an ionic hyper-crosslinked polymer according to claim 1, characterized in that: In the planetary ball milling process, the size of the grinding medium balls includes at least one of 5 mm, 10 mm, and 15 mm.

6. The method for preparing an ionic hyper-crosslinked polymer according to claim 1, characterized in that: The rotation speed of the planetary ball milling treatment is 100-500 rpm; the treatment time is 10-60 min.

7. The method for preparing an ionic hyper-crosslinked polymer according to claim 1, characterized in that: After the reaction is completed, a poor solvent is used to transfer the product, and the product is recovered and purified through filtering, washing, extraction and drying to obtain an ionic hyper-crosslinked polymer.

8. The method for preparing an ionic hyper-crosslinked polymer according to claim 7, characterized in that: The poor solvent includes at least one of water, methanol, ethanol, acetone, and ethyl acetate; the drying temperature is 60-200° C., and the drying time is 8-24 h.

9. An ionic hyper-crosslinked polymer, characterized in that: The method is as described in any one of claims 1 to 8.

10. An application of the ionic hyper-crosslinked polymer as claimed in claim 9, characterized in that: Including use as adsorbent material for carbon dioxide adsorption treatment.

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