High-hygroscopicity ionic polymer material as well as preparation method and application thereof

Abstract

The invention discloses a high-hygroscopicity ionic polymer material as well as a preparation method and application thereof. The high-hygroscopicity ionic polymer material is prepared by polymerizing a hygroscopicity ionic liquid monomer and a chain polymer free radical and then adjusting the aperture. The high-hygroscopicity ionic polymer material can reach 1.65 g / g in moisture absorption within 12 hours at the normal temperature under the humidity of 90%. The hygroscopic ionic polymer has an adjustable porous structure and high-density hygroscopic ions in structure, has high hygroscopicity and good machinability in performance, and can be widely applied to the aspects of drying, dehumidification, adsorption and heat storage, seawater desalination, sewage treatment and the like.

Description

Technical Field

[0001] This application relates to a highly hygroscopic ionic polymer material, its preparation method, and its application, belonging to the fields of adsorption and polymers. Background Technology

[0002] Water vapor adsorption technology plays a vital role in atmospheric water collection, low-grade waste heat utilization, adsorption temperature control, and energy conservation and emission reduction in air conditioning systems. Water vapor adsorbents have significant application potential and background in addressing water scarcity, improving energy efficiency, reducing greenhouse gas emissions, and promoting interdisciplinary technological development. Currently, commonly used water vapor adsorbents are mainly porous materials and inorganic salts. Most porous materials exhibit low adsorption rates under low pressure, while inorganic salt adsorbents are prone to solution leakage after absorbing moisture, posing a significant corrosive effect on equipment. Therefore, developing an easy-to-operate, high-performance water vapor adsorbent is of great importance.

[0003] Ionic liquids, as green media and soft functional materials, possess characteristics such as low vapor pressure, good stability, and high designability, and are widely used in green synthesis, biocatalysis, separation and extraction, and electrochemistry. Due to their salt-like nature, ionic liquids exhibit strong hygroscopicity, and their good stability and environmental friendliness make them ideal water vapor adsorbents. However, their high viscosity prevents them from fully contacting air, easily leading to the formation of a hydration layer on their surface, which hinders the subsequent adsorption of water molecules and reduces the water vapor adsorption rate. Summary of the Invention

[0004] Problems exist with existing technology:

[0005] (1) This invention provides a reasonable solution to the problem of low adsorption capacity of adsorption media in existing water vapor absorption technologies.

[0006] (2) This invention provides a solution to the problem that current water vapor adsorbents cannot simultaneously achieve both adsorption capacity and mechanical properties.

[0007] This invention synthesizes an ionomer adsorbent medium with high water vapor adsorption capacity and processability through free radical polymerization. This adsorbent medium utilizes the supporting effect of the polymer to greatly enhance its mechanical properties, and by controlling the pore size of the porous polymer, the specific surface area of ​​the adsorbent medium is increased, forming a large number of adsorption sites. Under the capillary condensation effect of the pores, the adsorption capacity of the adsorbent medium is greatly enhanced. The synthesized ionomer adsorbent exhibits high water vapor adsorption capacity due to its abundant pore structure and repeating hydrophilic ionic groups. Furthermore, this ionomer is leak-resistant and easy to process, and can be widely used in drying, dehumidification, adsorption heat storage, seawater desalination, and wastewater treatment.

[0008] According to one aspect of this application, a highly hygroscopic ionic polymer material is provided, which is prepared by adjusting the pore size after free radical polymerization of a hygroscopic ionic liquid monomer and a chain polymer.

[0009] Optionally, the anion in the hygroscopic ionic liquid monomer is selected from at least one of bromide ion, chloride ion, acetate anion, nitrate anion, sulfonic acid anion, methanesulfonic acid anion, carbonate anion, tetrafluoroborate anion, and trifluoroacetic acid anion.

[0010] Optionally, the cation in the hygroscopic ionic liquid monomer is selected from at least one of imidazoles, pyridines, pyrazoles, piperidines, triazoles, quaternary phosphines, and quaternary ammoniums containing C1 to C4 alkyl chains.

[0011] Optionally, the chain polymer is selected from at least one of poly(hydroxyethyl methacrylate), polyethylene glycol, polymethyl methacrylate, polyvinyl alcohol, sodium polyacrylate, and polyvinyl alcohol.

[0012] According to another aspect of this application, a method for preparing the above-described highly hygroscopic ionomer material is provided, the method comprising the following steps:

[0013] Step S1: A mixture of a nitrogen heterocyclic compound containing unsaturated functional groups, a haloalkane, and solvent I is reacted with reaction I to obtain a hygroscopic ionic liquid monomer.

[0014] Step S2: Stir the mixture containing hygroscopic ionic liquid monomer, crosslinking agent, chain polymer and solvent II in an inactive atmosphere, and then add initiator to carry out reaction II to obtain highly crosslinked ionic polymer;

[0015] Step S3: The highly cross-linked ionomer is subjected to pore formation and pore size adjustment to obtain the highly hygroscopic ionomer material.

[0016] Optionally, in step S1, the nitrogen heterocyclic compound with the unsaturated functional group is selected from at least one of N-allylimidazolium, N-vinylimidazolium, N-carboxyimidazolium, N-amidoimidazolium, N-vinylpyrazole, N-allylpyrazole, N-carboxypyrazole, N-amidoimidazolium, N-vinyltriazole, N-allyltriazole, N-amidotriazole, N-carboxypyrazole, N-allylpyridine, N-vinylpyridine, N-carboxypyridine, N-amidopyridine, N-allylpiperidine, N-vinylpiperidine, N-carboxypiperidine, and N-amidopiperidine.

[0017] Optionally, the haloalkane is selected from at least one of 1-bromobutane, 1-chlorobutane, 1-iodobutane, bromoethane, iodoethane, 3-bromo-1-propene, and 2-chlorobutane.

[0018] Optionally, the solvent I is selected from at least one of ethanol, diethyl ether, chloroform, carbon tetrachloride, methanol, ethyl acetate, water, acetonitrile, acetone, N-methylpyrrolidone, and toluene.

[0019] Optionally, the molar ratio of the nitrogen heterocyclic compound with unsaturated functional groups to the halohydrocarbon is 0.2:10 to 10:01.

[0020] Optionally, in step S2, the crosslinking agent is selected from at least one of divinylbenzene, diisocyanate, glutaric acid, ethylene glycol, diallyl disulfide, and diallyl dimethyl ammonium chloride.

[0021] Optionally, the chain polymer is selected from at least one of poly(hydroxyethyl methacrylate), polyethylene glycol, polymethyl methacrylate, polyvinyl alcohol, sodium polyacrylate, and polyvinyl alcohol.

[0022] Optionally, the initiator is selected from at least one of azobisisobutyronitrile, benzoyl peroxide, tert-butyl peroxide, methyl ethyl ketone peroxide, potassium persulfate, and dimethyl azobisisobutyronitrile.

[0023] Optionally, the solvent II is selected from at least one of ethanol, diethyl ether, chloroform, carbon tetrachloride, methanol, ethyl acetate, water, acetonitrile, acetone, N-methylpyrrolidone, and toluene.

[0024] Optionally, the contents of the hygroscopic ionic liquid monomer, crosslinking agent, chain polymer, and initiator are 20-80 wt%, 5-40 wt%, 5-40 wt%, and 1-15 wt%, respectively.

[0025] Optionally, in step S2, reaction II is free radical polymerization.

[0026] Optionally, the free radical polymerization includes at least one of thermal polymerization, radiation polymerization, microwave polymerization, and ultraviolet light polymerization.

[0027] Optionally, the reaction conditions for the thermal polymerization are: a reaction temperature of 50–120°C, a reaction time of 3–48 h, a drying temperature of 40–90°C, and a drying time of 12–48 h.

[0028] Optionally, the reaction conditions for radiation polymerization are as follows: the radiation source is selected from gamma rays or electron beams, the radiation dose is 0.0001 to 200 Gy, the reaction temperature is 20 to 100 °C, the reaction time is 0.5 to 2 h, and the stirring speed is 100 to 600 rpm.

[0029] Optionally, the microwave polymerization reaction conditions are as follows: microwave power of 200-800W, reaction time of 1-2h, reaction temperature of 60-120℃, and microwave radiation program of alternating on and off for 10-30s each.

[0030] Optionally, the reaction conditions for the ultraviolet polymerization are: a reaction temperature of 20–50°C, an effective wavelength of ultraviolet light of 200–365 nm, a power of 8–20 W, and an ultraviolet light intensity of 400–800 mW / cm². 2 The UV polymerization time is 120–480 min.

[0031] Optionally, the pore-forming and pore-size adjustment methods are selected from at least one of the following: hard template method, soft template method, freeze-drying method, solvothermal method, ionothermal method, anion exchange method, and post-modification method.

[0032] Optionally, after anion exchange or solvent exchange, freeze-drying may be used for further pore formation.

[0033] Optionally, the conditions for controlling the polymer pore size using the anion exchange method are: stirring and soaking time of 5 to 36 hours, and drying of the resulting solid product under vacuum at 30 to 120°C for 12 to 36 hours.

[0034] Optionally, when the freeze-drying method is used to control the polymer pore size, the pretreatment method for highly cross-linked ionic polymers is to freeze them in a refrigerator at -20°C for 4 to 72 hours.

[0035] Optionally, in step S1, the temperature of reaction I is 70–150°C, and the reaction time is 2–48 h.

[0036] Optionally, in step S2, the inactive atmosphere is selected from at least one of nitrogen, helium, and argon.

[0037] According to another aspect of this application, an application is provided for the above-described highly hygroscopic ionomer material in drying, dehumidification, adsorption heat storage, seawater desalination, sewage treatment, and energy conservation and emission reduction in air conditioning systems.

[0038] As an optional implementation, this application is achieved through the following technical solution:

[0039] The technical solution of the present invention includes the following steps:

[0040] (1) Preparation of hygroscopic ionic liquid monomer: A nitrogen heterocycle containing unsaturated functional groups and a haloalkane are dissolved in methanol solution and reacted. After the reaction is completed, the mixture is allowed to stand and separate into layers. The product is washed with diethyl ether and then dried under vacuum to obtain an ionic liquid containing halide anions. The reaction temperature is 70–150℃ and the reaction time is 2–48 h.

[0041] (2) Preparation of highly cross-linked ionic polymer: The hygroscopic ionic liquid monomer, cross-linking agent and chain polymer are dissolved in a solvent and stirred thoroughly under a nitrogen atmosphere for 0.5-12 h. Then, an initiator is added to carry out free radical polymerization reaction. The obtained product is washed with diethyl ether multiple times and then vacuum dried to obtain highly cross-linked ionic polymer.

[0042] (3) Further pore formation and pore size adjustment of the obtained highly cross-linked network polymer to obtain the final highly hygroscopic ionic polymer.

[0043] The method for preparing hygroscopic ionic liquid monomers in step (1) includes one of the following methods: using an ionic liquid containing halogen anions as raw material to prepare an alkaline ionic liquid by ion exchange; using an alkaline ionic liquid as raw material to prepare other ionic liquids containing acidic anions by acid-base neutralization; or preparing hygroscopic ionic liquids with different anions by precipitation.

[0044] Furthermore, the cation in the hygroscopic ionic liquid monomer prepared in step (1) is one of the following: imidazole, pyridine, pyrazole, triazole, piperidine, quaternary phosphine, quaternary ammonium; and the anion is one of the following: chloride ion, bromide ion, nitrate anion, tetrafluoroborate anion, trifluoroacetic acid anion, acetic acid anion, sulfonic acid, and methanesulfonic acid anion.

[0045] In this application, a highly cross-linked network polymer is obtained by free radical polymerization of a hygroscopic ionic liquid monomer and a chain-like hygroscopic polymer. The pore size of this network polymer is then adjusted to obtain a highly hygroscopic ionic polymer. This hygroscopic ionic polymer possesses both an adjustable porous structure and a high density of hygroscopic ions, and exhibits high hygroscopicity and good machinability.

[0046] In this application, the highly hygroscopic ionomer material can adsorb 1.65 g / g of water in 12 hours at room temperature and 90% humidity. The hygroscopic ionomer possesses both an adjustable porous structure and a high density of hygroscopic ions, exhibiting high hygroscopicity and good machinability. It can be widely used in drying, dehumidification, heat storage, seawater desalination, and wastewater treatment.

[0047] The beneficial effects that this application can produce include:

[0048] 1) The free radical polymerization method provided in this application synthesizes a porous ion polymer material with high water vapor adsorption capacity. While maintaining a certain water vapor adsorption capacity, it increases the mechanical properties of the adsorbent and solves the leakage and corrosion problems of salt adsorbents.

[0049] 2) The water vapor adsorbent provided in this application has high water vapor adsorption capacity and mechanical processability, and plays an important role in continuous air adsorption for water extraction, low-grade waste heat utilization, adsorption refrigeration, and energy saving and emission reduction of air conditioning systems. Attached Figure Description

[0050] Figure 1 This is a schematic diagram illustrating the synthesis of highly hygroscopic ionic polymers in the embodiments of this application.

[0051] Figure 2 This is a comparison chart of the hygroscopic properties of different substances in Test Example 1 of this application. Detailed Implementation

[0052] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0053] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0054] This application uses a constant temperature and humidity chamber and an automatic counting balance to test the moisture absorption. The test temperature is 25℃, the test humidity is 90%, and the test time is 12h.

[0055] In this application, a schematic diagram of the synthesis of the highly hygroscopic ionomer is shown below. Figure 1 As shown, Figure 1 As shown, the synthesized ionic polymers and nonionic polymers form an interpenetrating network structure, further enhancing the mechanical properties and swelling and water-retaining capacity of the hygroscopic material. The hygroscopic functional group A in the ionic polymer increases the surface adsorption sites, while the anions and cations in the ionic polymer increase the osmotic pressure during the polymer's moisture absorption process, further increasing the moisture absorption performance. Furthermore, the varying pore sizes distributed within the polymer increase capillary action, thereby increasing the moisture absorption rate.

[0056] Example 1

[0057] 25 g of purified N-allylimidazolium and 55 g of liquefied 1-bromobutane were dissolved in 100 ml of dichloromethane. The mixture was refluxed with cooling water at 75 °C and stirred for 12 h. The resulting product was then dried under vacuum at 60 °C for 24 h. The product was then completely dissolved in methanol solution and repeatedly passed through a chromatography column. 10 g of the basic intermediate obtained from column chromatography was added to 2.882 g of methanesulfonic acid and stirred for 12 h. The product was then rotary evaporated at 65 °C and dried under vacuum at 65 °C for 12 h to obtain the hygroscopic ionic liquid monomer.

[0058] 10 g of hygroscopic ionic liquid monomer, 4 g of divinylbenzene, 3.5 g of polyvinyl alcohol, and 0.3 g of azobisisobutyronitrile were dissolved in methanol, and the mixture was stirred thoroughly under nitrogen at room temperature for 2 hours. Then, azobisisobutyronitrile initiator was added, and the mixture was stirred under nitrogen at 65°C for 12 hours. The product was then distilled under reduced pressure, washed with diethyl ether and deionized water, and dried under vacuum at 80°C to obtain the highly crosslinked ionic polymer.

[0059] Take 5g of the above highly cross-linked ionomer product and saturated NaCl aqueous solution and place them in a round-bottom flask. Stir at 20°C for 10h. Filter to obtain the product, wash the product with anhydrous ethanol and deionized water, and dry under vacuum at 50°C for 12h to obtain the final ionomer material.

[0060] Example 2

[0061] The preparation of the hygroscopic ionic liquid monomer was the same as in Example 1. 10g of the prepared highly hygroscopic ionic liquid monomer, 4g of divinylbenzene, 4g of sodium polyacrylate, and 0.5g of phenyl ketone were crosslinked under ultraviolet light at 40°C. The power of the ultraviolet light used was 12W, and the intensity was 500mW / cm². 2 This process ultimately forms a highly cross-linked interpenetrating network ionomer. The polymer is soaked in distilled water and stirred to perform solvent exchange. It is then frozen at -20°C for 8 hours and finally placed in a freeze dryer to remove water, yielding a porous ionomer material with abundant pores.

[0062] Example 3

[0063] The preparation of the hygroscopic ionic liquid monomer was the same as in Example 1. 15g of the prepared highly hygroscopic ionic liquid monomer, 4g of divinylbenzene, 5g of sodium polyacrylate, and 0.45g of azobisisobutyronitrile were used. The microwave reaction was conducted at 400W for 1 hour at a temperature of 70℃, with alternating on and off cycles of 20 seconds each. The polymer was obtained by soaking in distilled water and stirring for 1 hour to allow solvent exchange. This process was repeated 10 times. The polymer was then frozen at -20℃ for 8 hours and finally dried in a freeze dryer to obtain a porous polyionic liquid material with abundant pores.

[0064] Example 4

[0065] The hygroscopic ionic liquid monomer was prepared in the same manner as in Example 1. 10g of the prepared highly hygroscopic ionic liquid monomer, 4g of divinylbenzene, 6g of sodium polyacrylate, and 0.6g of azobisisobutyronitrile were crosslinked at 50°C using gamma rays as an energy source for 1.5h, with a radiation dose of 0.22Gy. The resulting polymer was soaked in distilled water and stirred to exchange the solvent. The polymer after solvent exchange was then frozen at -20°C for 12h, and finally placed in a freeze dryer to remove water, yielding a porous ionic polymer material with abundant pores.

[0066] Test Example 1

[0067] The hygroscopic properties of the highly hygroscopic ionomer material prepared in Example 2 and its monomer were tested using a constant temperature and humidity chamber and an automatic counting balance at 25°C and 90% humidity. The results showed that the prepared hygroscopic polymer had a higher moisture absorption capacity and a faster moisture absorption rate than its monomer.

[0068] like Figure 2 As shown, Figure 2 In this context, monomer 1 refers to the hygroscopic ionic liquid prepared in Example 1, monomer 2 refers to sodium polyacrylate, and the ionic polymer refers to the highly hygroscopic ionic polymer material prepared in Example 2. Figure 2 It can be seen that the moisture absorption of the ionomer prepared at 90% humidity within 12 hours reaches 1.65 g / g.

[0069] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A superabsorbent ionic polymeric material, characterized by, The high-hygroscopic ionic polymer material is prepared by adjusting the pore size after the hygroscopic ionic liquid monomer is polymerized with a chain polymer free radical.

2. The superabsorbent ionic polymer material of claim 1, wherein, The anion in the hygroscopic ionic liquid monomer is at least one selected from bromide, chloride, acetate, nitrate, sulfonate, methyl sulfonate, carbonate, tetrafluoroborate, trifluoroacetate; Preferably, the cation in the hygroscopic ionic liquid monomer is at least one selected from imidazole, pyridine, pyrazole, piperidine, triazole, quaternary phosphonium, quaternary ammonium containing C1-C4 alkyl chain; Preferably, the chain polymer is at least one selected from polyhydroxyethyl methacrylate, polyethylene glycol, polymethyl methacrylate, polyvinyl alcohol, polyacrylic acid sodium, polyvinyl alcohol.

3. The method of producing a superabsorbent ionic polymer material according to any one of claims 1 to 2, characterized by, The preparation method comprises the following steps: Step S1: a mixture containing unsaturated functional group nitrogen heterocyclic compound, halogenated hydrocarbon, solvent I, reaction I, to obtain a hygroscopic ionic liquid monomer; Step S2: a mixture containing hygroscopic ionic liquid monomer, crosslinking agent, chain polymer, solvent II is stirred in an inactive atmosphere, and then an initiator is added to carry out reaction II, to obtain a high-crosslinking ionic polymer; Step S3: the high-crosslinking ionic polymer is subjected to pore forming and pore size adjustment, to obtain the high-hygroscopic ionic polymer material.

4. The production method according to claim 3, characterized by, In the step S1, the unsaturated functional group nitrogen heterocyclic compound is at least one selected from N-allyl imidazole, N-vinyl imidazole, N-carboxy imidazole, N-amido imidazole, N-vinyl pyrazole, N-allyl pyrazole, N-carboxy pyrazole, N-amido imidazole, N-vinyl triazole, N-allyl triazole, N-amido triazole, N-carboxy pyrazole, N-allyl pyridine, N-vinyl pyridine, N-carboxy pyridine, N-amido pyridine, N-allyl piperidine, N-vinyl piperidine, N-carboxy piperidine, N-amido piperidine; Preferably, the halogenated hydrocarbon is at least one selected from 1-bromobutane, 1-chlorobutane, 1-iodobutane, bromoethane, iodoethane, 3-bromo-1-propylene, 2-chlorobutane; Preferably, the solvent I is at least one selected from ethanol, diethyl ether, chloroform, carbon tetrachloride, methanol, ethyl acetate, water, acetonitrile, acetone, N-methyl pyrrolidone, toluene; Preferably, the molar ratio of the unsaturated functional group nitrogen heterocyclic compound to the halogenated hydrocarbon is 0.2:10-10:

01.

5. The preparation method according to claim 3, characterized in that, In the step S2, the crosslinking agent is at least one selected from divinylbenzene, diisocyanate, glutaric acid, ethylene glycol, diallyl disulfide, diallyl dimethyl ammonium chloride; Preferably, the chain polymer is at least one selected from polyhydroxyethyl methacrylate, polyethylene glycol, polymethyl methacrylate, polyvinyl alcohol, polyacrylic acid sodium, polyvinyl alcohol; Preferably, the initiator is at least one selected from azobisdimethyl isobutyronitrile, benzoyl peroxide, tert-butyl peroxybenzoate, methyl ethyl ketone peroxide, potassium persulfate, dimethyl azobis isobutyrate. Preferably, the solvent II is selected from at least one of ethanol, diethyl ether, chloroform, carbon tetrachloride, methanol, ethyl acetate, water, acetonitrile, acetone, N-methyl pyrrolidone, toluene; Preferably, the content of the hygroscopic ionic liquid monomer, the crosslinking agent, the chain polymer, and the initiator is 20-80wt%, 5-40wt%, 5-40wt%, and 1-15wt%, respectively.

6. The preparation method according to claim 3, characterized in that, In the step S2, the reaction II is a free radical polymerization. Preferably, the free radical polymerization includes at least one of thermal polymerization, radiation polymerization, microwave polymerization, and ultraviolet light polymerization. Preferably, the reaction condition of the thermal polymerization is that the reaction temperature is 50-120℃, the reaction time is 3-48h, the drying temperature is 40-90℃, and the drying time is 12-48h. Preferably, the reaction condition of the radiation polymerization is that the ray source is selected from γ-rays or electron beams, the radiation dose is 0.0001-200Gy, the reaction temperature is 20-100℃, the reaction time is 0.5-2h, and the stirring speed is 100-600rpm. Preferably, the reaction condition of the microwave polymerization is that the microwave power is 200-800W, the reaction time is 1-2h, the reaction temperature is 60-120℃, and the microwave radiation program is that the start and stop are alternately performed for 10-30s. Preferably, the reaction conditions of the ultraviolet photopolymerization are: reaction temperature 20-50°C, effective wavelength of ultraviolet light 200-365 nm, power 8-20 W, ultraviolet light intensity 400-800 mW / cm 2 , ultraviolet polymerization time 120-480 min.

7. The preparation method according to claim 3, characterized in that, The pore-forming and pore size adjusting method is selected from at least one of hard template method, soft template method, freeze-drying method, solvothermal method, ionothermal method, anion exchange method, and post-modification method.

8. The preparation method according to claim 3, characterized in that, After the anion exchange method or the solvent exchange method, the freeze-drying method is used for further pore-forming. Preferably, when the anion exchange method is used for regulating the pore size of the polymer, the stirring and soaking time is 5-36h, and the drying condition of the obtained solid product is vacuum drying at 30-120℃ for 12-36h. Preferably, when the freeze-drying method is used for regulating the pore size of the polymer, the pretreatment method of the high-crosslinking ionic polymer is freezing in a refrigerator at -20℃ for 4-72h.

9. The preparation method according to claim 3, characterized in that, In the step S1, the temperature of the reaction I is 70-150℃, and the time of the reaction I is 2-48h. Preferably, in the step S2, the non-active atmosphere is selected from at least one of nitrogen, helium, and argon.

10. Application of the high-hygroscopic ionic polymer material in any one of claims 1-2 in drying, dehumidification, adsorption heat storage, seawater desalination, sewage treatment, air conditioning system energy saving and emission reduction.

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