Polymer membrane based on neopentane crosslinked piperidine and preparation method and application thereof

Abstract

The invention provides a polymer film based on neopentane crosslinked piperidine as well as a preparation method and application of the polymer film, and belongs to the technical field of high polymer materials. The preparation method comprises the following steps: dissolving a ketone-based reactant and an aromatic reactant in a first organic solvent, reacting under the action of an acid catalyst, then adding into a first precipitant, precipitating, washing and drying to obtain polymer powder of polyarylpiperidine; dissolving in a second organic solvent, adding a first methylation reagent and an alkaline reagent for reaction, adding a second precipitator for precipitation, washing and drying to obtain partially quaternized polymer powder; dissolving in a third organic solvent, adding a neopentane cross-linking agent, reacting, and evaporating to obtain a partially quaternized neopentane cross-linked polymer film; and dissolving in a fourth organic solvent, reacting with a second methylation reagent, and evaporating to obtain the polymer film containing neopentane crosslinked piperidine. The preparation method is simple, raw materials are convenient to obtain, and the method is suitable for the fields of fuel cells or electrolyzed water.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to a polymer film based on neopentane cross-linked piperidine and a preparation method and application thereof. BACKGROUND

[0002] In recent years, hydrogen energy is regarded as an important energy for replacing fossil energy and realizing sustainable development due to its rich reserves and clean environmental protection. Among many hydrogen energy technologies, anion exchange membrane water electrolysis (AEMWE) has the advantages of proton exchange membrane water electrolysis and alkaline water electrolysis, can use non-noble metal catalysts under alkaline conditions, significantly reduces the system cost, and has a broad application prospect. As the core component of AEMWE, the anion exchange membrane (AEM) bears the key functions of hydrogen and oxygen ion conduction and gas separation, and its performance directly affects the system efficiency and durability. However, the practical application of the current AEM still faces two major challenges: first, the ion conductivity is insufficient, which is difficult to meet the demand of efficient water electrolysis for hydrogen production; second, the stability is limited in a high-temperature strong alkali environment, and the ion groups and main chain structure are prone to degradation, resulting in shortening of the membrane life.

[0003] To improve the performance of AEM, researchers have proposed various molecular design strategies, such as constructing a full-carbon main chain to enhance alkali stability, introducing block or long side chain structure to improve microphase separation and enhance conductivity. At the same time, cross-linking strategies are also used to improve the mechanical properties and dimensional stability of the membrane. Although related research has made progress, there are still the following problems: first, improving the conductivity often leads to increased swelling or decreased mechanical properties, making it difficult to balance the overall performance; second, some cross-linking agents contain beta-hydrogen atoms, which are prone to degradation under strong alkali conditions, limiting the long-term stability of the material. Therefore, how to balance high ion conductivity and excellent alkali stability while maintaining good mechanical strength and dimensional stability is still a key technical problem to be solved in the field. SUMMARY

[0004] The purpose of the present application is to overcome the deficiencies in the prior art, and to provide a polymer film based on neopentane cross-linked piperidine and a preparation method and application thereof. The preparation method is simple, the raw materials are easy to obtain, and the provided polymer film can effectively improve the ion conductivity and alkali stability of the polymer electrolyte.

[0005] The present application provides the following technical solutions:

[0006] In a first aspect, a polymer film based on neopentane cross-linked piperidine has the following general structure:

[0007]

[0008] wherein Ar is an aryl building block, and X has a value of 0.25 to 25, preferably 1.25 to 5.

[0009] In a second aspect, there is provided a method of making a neopentane crosslinked piperidine-based polymer membrane according to the first aspect, comprising the steps of:

[0010] dissolving a ketone-based reactant and an aromatic reactant in a first organic solvent, reacting in the presence of an acid catalyst, followed by precipitation with a first precipitant, washing and drying to obtain a polyarylpiperidine polymer powder;

[0011] dissolving the polyarylpiperidine polymer powder in a second organic solvent, adding a first methylation reagent and a basic reagent to react, followed by precipitation with a second precipitant, washing and drying to obtain a partially quaternized polymer powder;

[0012] dissolving the partially quaternized polymer powder in a third organic solvent, adding a neopentane crosslinking reagent to react and evaporating to obtain a partially quaternized neopentane crosslinked polymer membrane;

[0013] dissolving the partially quaternized neopentane crosslinked polymer membrane in a fourth organic solvent, reacting with a second methylation reagent, and evaporating after the reaction to obtain a neopentane crosslinked piperidine-based polymer membrane.

[0014] Further, the ketone-based reactant comprises any one or more of the following carbonyl compounds:

[0015]

[0016] wherein R1 is a hydrogen ion group, or a hydrocarbon group having a carbon atom number of 1 to 30, R2 and R3 are each independently a hydrocarbon group having a carbon atom number of 1 to 30, R4 is a halogenated hydrocarbon group or a hydrocarbon group having a carbon atom number of 1 to 30, R5 is a cyclic alkane containing a nitrogen atom, R6 is an aryl group, optionally substituted with halogen, nitro or cyano, and R7 is a halogenated hydrocarbon group or a hydrocarbon group having a carbon atom number of 1 to 30;

[0017] The aromatic reactant comprises any one or more of the following structures: ; ; ; ; ; ; ; ; .

[0018] Further, the molar ratio of the aromatic reactant and the ketone reactant is 1: (1.1~1.2).

[0019] Further, the molar ratio of the first methylation agent and the polymer powder of polyaryl piperidine is (1.5~2):4, and the molar ratio of the basic agent and the polymer of polyaryl piperidine is (2.5~3):3.

[0020] Further, the ketone reactant and the aromatic reactant are dissolved in the first organic solvent, and reacted under the action of the acid catalyst at -10℃~100℃ for 0.1 h~96 h, followed by precipitation by adding the first precipitant, washing and drying to obtain the polymer powder of polyaryl piperidine; preferably, the temperature range is 20℃~30℃, and the reaction time is 8 h~48 h.

[0021] The polymer powder of polyaryl piperidine is dissolved in the second organic solvent, and the first methylation agent and the basic agent are added for reaction, the reaction temperature range is 20℃~50℃, and the reaction time is 24 h~72 h, followed by precipitation by adding the second precipitant, washing and drying to obtain the partially quaternized polymer powder.

[0022] Further, the mass concentration of the partially quaternized polymer powder in the third organic solvent is 3 wt%~10 wt%, and the molar ratio of the neopentane crosslinking agent and the partially quaternized polymer powder is 1: (1.25~5), and the evaporation temperature range after adding the neopentane crosslinking agent for reaction is 80℃~150℃.

[0023] Further, the molar ratio of the second methylation agent and the partially quaternized neopentane crosslinked polymer film is (2~3):4, and the evaporation temperature range after the reaction with the second methylation agent is 80℃~150℃.

[0024] Further, the second organic solvent, the third organic solvent and the fourth organic solvent each include any one or more of dimethyl sulfoxide, N-methyl pyrrolidone, N-dimethyl formamide, N,N-dimethyl acetamide, trichloromethane, tetrahydrofuran.

[0025] In a third aspect, the application provides an application of the neopentane crosslinked piperidine-based polymer film of the first aspect or the neopentane crosslinked piperidine-based polymer film prepared by the method of any one of the second aspect, as an anion exchange membrane or a catalyst layer binder.

[0026] Compared with the prior art, the application has the following beneficial effects: (1) The application provides a preparation method of a piperidine polymer film based on neopentane crosslinking, wherein the introduced neopentane crosslinking agent has a tetrahedral structure, which can effectively limit the excessive movement of the polymer main chain, thereby reducing the swelling phenomenon and improving the dimensional stability and mechanical strength of the anion exchange film; the neopentane crosslinking agent used in the application is a small molecular structure, which can tightly connect four piperidine groups, promote the aggregation of cation groups, and is conducive to the formation of obvious microphase separation structure, thereby improving the continuity of the ion channel and enhancing the anion conduction performance; the neopentane crosslinking agent used in the application does not contain β-hydrogen atoms, avoids the formation of degradation sites, has high chemical inertness, and thus significantly improves the chemical stability of the film. (2) The preparation method provided by the application is simple and the raw materials are convenient to obtain; the prepared polymer film can have high ion conductivity and excellent alkali stability, and also has good mechanical strength and dimensional stability, and is suitable for the field of water electrolysis hydrogen production. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of the anion exchange film (X=1.25) introduced with the neopentane crosslinking agent in the embodiment 1 of the application; Figure 2 is the nuclear magnetic resonance hydrogen spectrum of the anion exchange film (X=5) introduced with the neopentane crosslinking agent in the embodiment 2 of the application; Figure 3 is the nuclear magnetic resonance hydrogen spectrum of the anion exchange film (X=2.5) introduced with the neopentane crosslinking agent in the embodiment 3 of the application; Figure 4 is the nuclear magnetic resonance hydrogen spectrum of the anion exchange film without the introduction of the neopentane crosslinking agent in the comparative example 1 of the application; Figure 5 is a curve graph of the water absorption rate of the anion exchange films in the embodiment 1 and the comparative example 1 of the application changing with temperature; Figure 6 is a curve graph of the swelling rate of the anion exchange films in the embodiment 1 and the comparative example 1 of the application changing with temperature; Figure 7 is a mechanical tensile strength curve of the anion exchange films in the embodiment 1 and the comparative example 1 of the application; Figure 8 is a curve graph of the hydroxyl ion conductivity of the anion exchange films in the embodiment 1 and the comparative example 1 of the application changing with temperature; Figure 9 is a data graph of the hydroxyl ion conductivity retention rate of the anion exchange films in the embodiment 1 and the comparative example 1 of the application after alkali immersion for 3000 hours. DETAILED DESCRIPTION

[0028] The application will be further described below with reference to the drawings. The following examples are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0029] In the description of the application, it should be understood that the terms "first", "second" and the like are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more features. In the description of the application, unless otherwise specified, the meaning of "multiple" is two or more. As for "contain", "include", "have", "contain" and the like used herein, they are all open terms, that is, they mean containing but not limited to.

[0030] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the application is described. Although only preferred methods and materials are described in the application, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the application.

[0031] The application introduces a neopentane crosslinking agent to prepare a neopentane crosslinking-based polymer film and apply it in an anion exchange membrane to improve the ionic conductivity, alkaline stability and mechanical properties of the anion exchange membrane. In some possible embodiments, the neopentane crosslinking agent is a small molecule crosslinking agent with a tetrahedral structure, the scientific name of which is tetrabromoneopentane, the English name is Tetrabromoneopentane, and the CAS number is 3229-00-3.

[0032] The application provides a neopentane crosslinking piperidine-based polymer film, which comprises the following steps: S1. Dissolve the ketone reactant and the aromatic reactant in a first organic solvent, react under the action of an acid catalyst, and react at-10℃~100℃ for 0.1 h~96 h. When the reaction mixture becomes viscous, a polyaryl piperidine polymer solution is obtained, and then a first precipitant is added for precipitation, washing and drying to obtain a polyaryl piperidine polymer powder; S2. Dissolve the polyaryl piperidine polymer powder in a second organic solvent, add a first methylation reagent and a basic reagent to react at 0℃~100℃ for 0.1 h~96 h to obtain a polymer solution with partial quaternary ammonium salt, and then slowly add the solution to a second precipitant for precipitation, washing and drying to obtain a partially quaternized polymer powder; S3. The partially quaternized polymer powder is dissolved in a third organic solvent, after purification by filtering with a 0.45 pm polytetrafluoroethylene filter head, a neopentane crosslinking agent is added for reaction and evaporation, a neopentane crosslinked polymer film is obtained by casting on a glass plate at 80°C~160°C using a flow casting method, and after removing the third organic solvent. S4. The partially quaternized neopentane crosslinked polymer film is dissolved in a fourth organic solvent, after purification by filtering with a 0.45 pm polytetrafluoroethylene filter head, a second methylation reagent is added for reaction and evaporation, a neopentane crosslinked piperidine-containing polymer film is obtained by casting on a glass plate at 80°C~160°C using a flow casting method, and after removing the fourth organic solvent.

[0033] The general structure of the polymer film is as follows:

[0034]

[0035] In the formula, Ar is an aryl structural monomer, and X is 0.25~25, preferably, X is 1.25~5.

[0036] In some possible embodiments, the molar ratio of the ketone-based reactant to the acid catalyst is 1:(1~30), and the acid catalyst includes any one or more of methanesulfonic acid, trifluoroacetic acid, acetic acid, trifluoromethanesulfonic acid, pentafluoropropionic acid, heptafluorobutyric acid, or perfluorosulfonic acid.

[0037] In some possible embodiments, the first precipitant and the second precipitant each include any one or more of deionized water, methanol, ethanol, acetone, isopropanol, diethyl ether, n-hexane, cyclohexane, petroleum ether, ethyl acetate, dichloromethane, tetrahydrofuran, toluene, chloroform, acetonitrile, and tert-butanol; the first precipitant includes a 0.01 mol / L~1 mol / L lye, and the alkali in the lye is any one or more of sodium bicarbonate, potassium bicarbonate, cesium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, calcium oxide, and calcium hydroxide; preferably, the first precipitant includes a mixed solvent of deionized water and methanol or ethanol, or an aqueous solution of sodium bicarbonate or potassium bicarbonate.

[0038] In some possible embodiments, the first methylation reagent and the second methylation reagent each comprises any one or more of dimethyl sulfate, diethyl sulfate, dibenzyl sulfate, p-toluenesulfonate, triflate, methylsulfonium tetrafluoroborate, iodomethane, iodoethane, iodopropane, iodobutane, iodopentane, iodohexane, iodheptane, iodoctane, iodononane, iododecane, bromomethane, bromoethane, bromopropane, bromobutane, bromopentane, bromohexane, bromoheptane, bromooctane, bromononane, bromodecane, 2-bromoethylamine, 2-bromoethanol, cyclopropyl iodide, isopropyl iodide, isobutyl iodide, cyclopentyl iodide, cyclohexyl iodide, (5-bromopentyl)trimethylammonium bromide, t-butyl iodide, neopentyl iodide, benzyl iodide, iodododecane; the basic substance of the basic reagent comprises any one or more of sodium bicarbonate, potassium bicarbonate, cesium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, calcium oxide, calcium hydroxide.

[0039] In some possible embodiments, the first organic solvent comprises any one or more of dichloromethane, trichloromethane, carbon tetrachloride, Eaton's reagent, dichloroethane, tetrachloroethane, nitrotoluene, nitrobenzene, toluene, tetrahydrofuran, or diethyl ether.

[0040] The present application provides a preparation method of an anion exchange membrane containing different kinds of accompanying ions, comprising the following steps: The polymer membrane prepared above based on neopentane cross-linked piperidine is soaked in an aqueous solution containing different kinds of accompanying ions, the concentration of the aqueous solution of accompanying ions is 0.1 mol / L ~ 10 mol / L, and ion exchange is performed at room temperature or under heating, so as to obtain an anion exchange membrane containing different kinds of accompanying ions.

[0041] In some possible embodiments, the kinds of accompanying ions comprise any one or more of hydroxide ions, carbonate ions, bicarbonate ions, nitrate ions, bromide ions, fluoride ions, chloride ions. Preferably, lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, and hydroxide aqueous solutions of hydroxides configured by the above; sodium bicarbonate, potassium bicarbonate, cesium bicarbonate, ammonium bicarbonate, magnesium bicarbonate, and calcium bicarbonate configured bicarbonate salt solutions; sodium carbonate, potassium carbonate, cesium carbonate, calcium carbonate configured carbonate aqueous solutions; sodium bromide, potassium bromide, cesium bromide, ammonium bromide, magnesium bromide, and calcium bromide configured bromide aqueous solutions; sodium chloride, potassium chloride, cesium chloride, ammonium chloride, magnesium chloride, and calcium chloride configured chloride aqueous solutions; sodium fluoride, potassium fluoride, cesium fluoride, ammonium fluoride, magnesium fluoride, and calcium fluoride configured fluoride aqueous solutions; sodium nitrate, potassium nitrate, cesium nitrate, ammonium nitrate, magnesium nitrate, and calcium nitrate configured nitrate aqueous solutions.

[0042] The present application provides a method for preparing a catalyst layer binder, comprising the following steps: After the polymer film containing neopentane cross-linked piperidine prepared above is completely dissolved in the fifth organic solvent, the catalyst layer binder solution rich in high ionic conductivity anion exchange membrane polymer is obtained after filtering and purifying using a 0.45 pm polytetrafluoroethylene filter head, and the mass concentration of the catalyst layer binder solution is 0.01 wt% to 20 wt%.

[0043] In some possible embodiments, the fifth organic solvent includes any one or more of dimethyl sulfoxide, N-methyl pyrrolidone, N-dimethyl formamide, N,N-dimethyl acetamide, trichloromethane, or tetrahydrofuran.

[0044] Example 1

[0045] The present embodiment provides a polymer film containing neopentane cross-linked piperidine, and the preparation process and the structural formula of the ionic polymer of the present embodiment are as follows:

[0046]

[0047]

[0048]

[0049]

[0050] In the formula, Ar is p-terphenyl, and X = 1.25.

[0051] Dissolve 1.3 g, 11 mmol 1-piperidin-4-one and 2.3 g, 10 mmol p-terphenyl in 8 mL dichloromethane, cool the solution to 0°C, dropwise add 1.5 mL trifluoroacetic acid, stir for 30 min, then dropwise add 8 mL trifluoromethanesulfonic acid under ice bath for catalytic polycondensation reaction, react at 0°C for 9 h to obtain a dark blue viscous high molecular weight polymer, then slowly add to a mixed solution of methanol and water in a volume ratio of 1:1 to obtain a white polymer, crush after filtering, repeatedly wash with 1 M potassium carbonate aqueous solution and deionized water, and vacuum dry at 80°C for 48 h to obtain 17.2 g of a yellowish polymer powder of polyaryl piperidine.

[0052] Take 10 g of polymeric powder of polyarylpiperidine and dissolve in 100 mL of dimethyl sulfoxide, add 1.5 g of iodomethane in batches, then add 7.27 g of potassium carbonate, and react at 30°C for 48 h in the dark to carry out methylation; after the reaction is completed, pour into 200 mL of ethyl acetate to precipitate, wash with deionized water for three times after filtration, and vacuum dry to obtain 6.4 g of light yellow partially quaternized polymer powder.

[0053] Take 3.5 g of partially quaternized polymer powder and dissolve in 100 mL of dimethyl sulfoxide, add 0.05 g of tetrabromononane, then slowly and uniformly pour the solution onto a glass plate, and place in an oven at 100°C for 24 h to carry out quaternization reaction and crosslinking, and after the solvent evaporates, a partially quaternized nonane crosslinked polymer film is obtained.

[0054] Take 3 g of partially quaternized nonane crosslinked polymer film and dissolve in 100 mL of dimethyl sulfoxide, add 2 g of iodomethane, and react at 30°C for 48 h in the dark to carry out methylation, then slowly and uniformly pour the solution onto a glass plate, and place in an oven at 80°C for 24 h to carry out quaternization reaction, and after the solvent evaporates, a nonane crosslinked piperidine-containing polymer film is obtained.

[0055] The nonane crosslinked piperidine-containing polymer film is washed with deionized water, and the surface moisture is wiped dry with a dust-free paper to obtain an anion exchange membrane with iodine ions as the accompanying ions, denoted as n-QPTM-5.

[0056] The hydrogen nuclear magnetic resonance spectrum of n-QPTM-5 is detected under a 600 MHz nuclear magnetic resonance spectrometer using DMSO-d6 as a deuterated reagent and adding 10% trifluoroacetic acid to remove the water peak, and it can be known from Figure 1 that the anion exchange membrane n-QPTM-5 introducing a nonane crosslinking agent is successfully prepared in this embodiment.

[0057] Example 2

[0058] This embodiment is based on the partially quaternized polymer powder provided in Example 1, and provides a nonane crosslinked piperidine-based polymer film, and the preparation process and the structure of the ionic polymer of this embodiment are as shown below:

[0059]

[0060]

[0061]

[0062] In the formula, Ar is p-terphenyl, and X = 5.

[0063] Take 3.5 g of partially quaternized polymer powder and dissolve it in 100 mL of dimethyl sulfoxide, add 0.2 g of tetrabromonewalkane, and then slowly and uniformly pour the solution onto a glass plate, and place it in an oven at 100°C for 24 h to carry out the quaternization reaction and crosslinking, and after the solvent evaporates, a partially quaternized newalkane crosslinked polymer film is obtained.

[0064] Dissolve 3 g of the partially quaternized newalkane crosslinked polymer film in 100 mL of dimethyl sulfoxide, add 2 g of iodomethane, and react for 48 h at 30°C in the dark to carry out methylation, and then slowly and uniformly pour the solution onto a glass plate, and place it in an oven at 80°C for 24 h to carry out the quaternization reaction, and after the solvent evaporates, a newalkane crosslinked piperidine-containing polymer film is obtained.

[0065] After washing the newalkane crosslinked piperidine-containing polymer film with deionized water and wiping off the surface moisture with a dust-free paper, an anion exchange membrane with iodine ions as the accompanying ions is obtained, and is denoted as n-QPTM-20.

[0066] Using DMSO-d6 as the deuterating agent and adding 10% trifluoroacetic acid to remove the water peak, the nuclear magnetic hydrogen spectrum of n-QPTM-20 is detected under a 600 MHz nuclear magnetic resonance spectrometer, and it can be seen from Figure 2 It can be seen that the anion exchange membrane n-QPTM-20 with the introduction of a newalkane crosslinking agent is successfully prepared in this embodiment.

[0067] Example 3

[0068] This embodiment is based on the partially quaternized polymer powder provided in Example 1, and provides a newalkane crosslinked piperidine-based polymer film, and the preparation process and the structure of the ionic polymer of this embodiment are as shown below:

[0069]

[0070]

[0071]

[0072] In the formula, Ar is p-terphenyl, and X = 2.5.

[0073] Take 3.5 g of partially quaternized polymer powder and dissolve it in 100 mL of dimethyl sulfoxide, add 0.2 g of tetrabromonewalkane, and then slowly and uniformly pour the solution onto a glass plate, and place it in an oven at 100°C for 24 h to carry out the quaternization reaction and crosslinking, and after the solvent evaporates, a partially quaternized newalkane crosslinked polymer film is obtained.

[0074] The 3 g partially quaternized neopentane cross-linked polymer film was dissolved in 100 mL dimethyl sulfoxide, 2 g iodomethane was added, and methylation was carried out at 30 °C in the dark for 48 h, and then the solution was slowly and uniformly cast onto a glass plate, and the quaternization reaction was carried out in an oven at 80 °C for 24 h, and after the solvent was evaporated, a neopentane cross-linked piperidine-containing polymer film was obtained.

[0075] After the neopentane cross-linked piperidine-containing polymer film was washed with deionized water, the surface moisture was wiped dry with a dust-free paper, an anion exchange film with iodine ions as the accompanying ions was obtained, and was denoted as n-QPTM-10.

[0076] The nuclear magnetic hydrogen spectrum of n-QPTM-10 was detected under a 600 MHz nuclear magnetic resonance spectrometer using DMSO-d6 as a deuterated reagent and adding 10 % trifluoroacetic acid to remove the water peak, and it was found that Figure 3 It can be seen that the neopentane cross-linking agent-introduced anion exchange film n-QPTM-10 was successfully prepared in this embodiment.

[0077] Example 4

[0078] This embodiment is based on the neopentane cross-linked piperidine-containing polymer film provided in Example 1, and provides a preparation method of a catalyst layer binder, which comprises the following steps:

[0079] After 1 g of the neopentane cross-linked piperidine-containing polymer film was completely dissolved in 20 mL dimethyl sulfoxide, the mass concentration of the catalyst layer binder solution was 5 wt%, and after being filtered and purified using a 0.45 µm polytetrafluoroethylene filter head, a catalyst layer binder solution rich in high ionic conductivity anion exchange film polymer was obtained.

[0080] Comparative Example 1

[0081] This comparative example is based on the polyaryl piperidine polymer powder provided in Example 1, and provides a preparation method of a quaternary ammonium salt polymer film, and the preparation process and the structural formula of the ionic polymer of this comparative example are as follows:

[0082] In the formula, Ar is p-terphenyl, and X = 0.

[0083] 10 g of the polyaryl piperidine polymer powder was dissolved in 100 mL dimethyl sulfoxide, 7.27 g of potassium carbonate was added in batches, and then 3 g of iodomethane was added, and methylation was carried out at 30 °C in the dark for 48 h; after the reaction was completed, the mixture was poured into 200 mL of ethyl acetate for precipitation, and after being filtered and washed with deionized water for three times, vacuum drying was performed, and 6.4 g of a light yellow quaternary ammonium salt polymer powder was obtained.

[0084] A 1 g of light yellow polymer powder was dissolved in 20 mL of dimethyl sulfoxide to obtain an ionomer solution with a concentration of about 5 wt%. The polymer solution was slowly and uniformly cast onto a glass plate and placed in an oven at 80°C for 24 h to completely remove the solvent. After peeling off, the surface moisture was dried with a dust-free paper after being washed with deionized water, and an anion exchange membrane with iodine ions as the accompanying ions was obtained, denoted as QPTM.

[0085] The hydrogen spectrum of the anion exchange membrane was detected by a 600 MHz nuclear magnetic resonance spectrometer using DMSO-d6 as a deuterated reagent and adding 10% trifluoroacetic acid to remove the water peak, and the results were as follows: Figure 4 It can be seen that the comparative example successfully prepared an anion exchange membrane QPTM without adding neopentane crosslinking agent.

[0086] Application Example 1

[0087] This application example tested the anion exchange membranes prepared in Examples 1-3 and Comparative Example 1, characterized their water absorption, swelling rate, mechanical properties and OH - ion conductivity and OH - ion conductivity retention rate after 3000 hours of alkaline soaking, and the test results are shown in Table 1.

[0088] Table 1 Test results of different anion exchange membranes

[0089]

[0090] As can be seen from Table 1, the performance of the anion exchange membranes prepared in Examples 1-3 is significantly better than that of the anion exchange membrane prepared in Comparative Example 1. Based on the above results, this application example introduces and analyzes Examples 1 and Comparative Example 1 in detail, and explores their various properties.

[0091] The n-QPTM-5 prepared in Example 1 and the QPTM prepared in Comparative Example 1 were cut into 4 cm x 4 cm samples, dried in an oven at 80°C for 24 h, and the weight of the dried anion exchange membrane was recorded. Then the dried anion exchange membrane was soaked in 1 mol / L KOH aqueous solution, and then washed with deionized water to obtain an anion exchange membrane with OH - as the accompanying ions. The anion exchange membrane with OH - as the accompanying ions was soaked in deionized water, and the water on the surface of the anion exchange membrane was wiped off every 12 h, and the weight of the anion exchange membrane after soaking at different temperatures of 30°C-80°C was recorded. The water absorption was calculated by the following formula:

[0092]

[0093] In the formula, WU represents the water absorption rate, W wet W represents the weight of the anion exchange membrane after soaking in deionized water. dry This indicates the weight of the anion exchange membrane before immersion in deionized water.

[0094] like Figure 5 The figure shows the curve of water absorption rate of the anion exchange membrane under test as a function of temperature. Figure 5 It can be seen that the water absorption rate of n-QPTM-5 at 80℃ is 27.3%, while the water absorption rate of QPTM is 37.5%.

[0095] The n-QPTM-5 prepared in Example 1 and the QPTM prepared in Comparative Example 1 were thoroughly dried and cut into 4 cm × 4 cm strips. The length of the dried anion exchange membrane after cutting was recorded as 4 cm. The dried anion exchange membrane was then immersed in a 1 mol / L KOH aqueous solution and thoroughly washed with deionized water to obtain an accompanying ion of OH. - Anion exchange membrane. The accompanying ion is OH-. - Anion exchange membranes were immersed in deionized water. Every 12 hours, the membranes were removed and dried. The length of the anion exchange membranes after immersion at different temperatures ranging from 30℃ to 80℃ was recorded. The swelling rate was calculated using the following formula:

[0096]

[0097] In the formula, SR represents the swelling ratio, and L wet The length (L) of the anion exchange membrane after soaking in deionized water. dry This indicates the length of the anion exchange membrane before immersion in deionized water.

[0098] like Figure 6 The figure shows the swelling ratio of the anion exchange membrane as a function of temperature. Figure 6 It can be seen that the swelling rate of n-QPTM-5 at 80℃ is 15.9%, and the swelling rate of QPTM is 20.3%.

[0099] This is because the introduced new pentane crosslinking agent can effectively limit the excessive movement of the polymer backbone, thereby reducing swelling.

[0100] The n-QPTM-5 prepared in Example 1 and the QPTM prepared in Comparative Example 1 were cut into strips with a length × width of 60 mm × 10 mm. Three parallel samples were set for each group of samples. The thickness of the samples was recorded using a micrometer screw gauge. The mechanical properties of the anion exchange membrane were determined using an electronic universal tensile tester at a tensile speed of 1 mm / min.

[0101] like Figure 7 The figure shows the mechanical tensile strength curve of the anion exchange membrane under test.Figure 7 It can be seen that the fracture stress and elongation at break of n-QPTM-5 are 52.9 MPa and 18.6%, respectively, while the fracture stress and elongation at break of QPTM are 38.1 MPa and 6.8%, respectively. This indicates that the introduction of the new pentane crosslinking agent can significantly improve the mechanical properties of the anion exchange membrane.

[0102] The n-QPTM-5 prepared in Example 1 and the QPTM prepared in Comparative Example 1 were cut into 1 cm × 4 cm strips, and then soaked in 1 mol / L KOH aqueous solution. After thorough washing with deionized water, the accompanying ion was OH. - The anion exchange membrane was clamped in a test fixture and placed in an electrolytic cell filled with deionized water. Electrodes were installed, and the electrochemical workstation was connected. Testing was performed in 0.1 mA constant current mode, with a scan frequency range of 1 MHz to 100 MHz. The resistance of the anion exchange membrane was determined using a four-electrode AC impedance method. The frequency range where impedance was stable was found on the Bode curve, and the resistance of the anion exchange membrane was read. The hydroxide ion conductivity σ was calculated using the following formula:

[0103]

[0104] In the formula, R is the resistance of the anion exchange membrane, L is the distance between the electrodes (1.0 cm), w is the membrane width, and d is the membrane thickness.

[0105] like Figure 8 The figure shows the curve of hydroxide ion conductivity of an anion exchange membrane as a function of temperature. Figure 8 It can be seen that at any temperature, the hydroxide ion conductivity of n-QPTM-5 is higher than that of QPTM; at 80℃, the hydroxide ion conductivity of n-QPTM-5 reaches 200 mS / cm, while that of QPTM is only 145 mS / cm. This indicates that the addition of neopentane crosslinking agent can significantly improve the anionic conductivity of the polymer.

[0106] The n-QPTM-5 prepared in Example 1 and the QPTM prepared in Comparative Example 1 were cut into 1 cm × 4 cm strips, and then soaked in 1 mol / L KOH aqueous solution. After thorough washing with deionized water, the accompanying ion was OH. - The anion exchange membrane was immersed in a 1 mol / L KOH aqueous solution for 3000 hours, thoroughly washed with deionized water, and its hydroxide ion conductivity was tested according to the above method. The hydroxide ion conductivity retention rate was calculated using the following formula:

[0107]

[0108] In the formula, σ1 is the conductivity of hydroxyl ions after the anion exchange membrane is soaked in alkali for 3000 hours, and σ2 is the conductivity of hydroxyl ions before the anion exchange membrane is soaked in alkali.

[0109] Figure 9 The data graph of the retention rate of the conductivity of hydroxyl ions of the anion exchange membrane after being soaked in alkali for 3000 hours is shown in Figure 4. Figure 9 It can be seen that, after being soaked in alkali for 3000 hours, the retention rate of the conductivity of hydroxyl ions of n-QPTM-5 is 92.3%, and the retention rate of the conductivity of hydroxyl ions of QPTM is 85.2%, which indicates that the addition of the neopentane crosslinking agent can significantly improve the alkali stability of the anion exchange membrane.

[0110] In summary, after the introduction of the neopentane crosslinking agent, the anion exchange membrane has good water absorption, moderate swelling rate and high anion conductivity, and at the same time has excellent alkali stability and mechanical properties, and can be applied to the fields of fuel cells and water electrolysis hydrogen production.

[0111] The above description is only the preferred embodiments of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A polymer film based on neopentane-crosslinked piperidine, characterized in that, The general structural formula of the polymer film is shown below: ； In the formula, Ar is an aryl monomer, and X takes values ​​from 0.25 to 25.

2. A method for preparing a polymer film based on neopentane-crosslinked piperidine as described in claim 1, characterized in that, Includes the following steps: The ketone reactant and the aromatic reactant are dissolved in a first organic solvent and reacted under the action of an acid catalyst. Then, a first precipitant is added to precipitate, wash and dry to obtain a polymer powder of polyarylpiperidine. Polyarylpiperidine polymer powder was dissolved in a second organic solvent, and a first methylating agent and a basic agent were added to react. Then a second precipitating agent was added to precipitate, and the mixture was washed and dried to obtain partially quaternized polymer powder. Part of the quaternized polymer powder was dissolved in a third organic solvent, and after reacting with a neopentane crosslinking agent, it was evaporated to obtain a partially quaternized neopentane crosslinked polymer film. The partially quaternized neopentane crosslinked polymer membrane was dissolved in a fourth organic solvent and reacted with a second methylating agent. After the reaction was completed, the mixture was evaporated to obtain a polymer membrane containing neopentane crosslinked piperidine.

3. The method for preparing a polymer film based on neopentane-crosslinked piperidine according to claim 2, characterized in that, The ketone reactant includes any one or more of the following carbonyl compounds: ； Wherein, R1 is a hydrogen ion group or a hydrocarbon group containing 1 to 30 carbon atoms, R2 and R3 are each independently a hydrocarbon group containing 1 to 30 carbon atoms, R4 is a halohydrocarbon group or hydrocarbon group containing 1 to 30 carbon atoms, R5 is a cycloalkanes containing nitrogen atoms, R6 is an aryl group, which may be substituted by halogen, nitro or cyano, and R7 is a halohydrocarbon group or hydrocarbon group containing 1 to 30 carbon atoms. The aromatic reactant comprises any one or more of the following structures: ； ； ； ； ； ； ； ； 。 4. The method for preparing a polymer film based on neopentane-crosslinked piperidine according to claim 2, characterized in that, The molar ratio of the aromatic reactant to the ketone reactant is 1:(1.1~1.2).

5. The method for preparing a polymer film based on neopentane-crosslinked piperidine according to claim 2, characterized in that, The molar ratio of the first methylating agent to the polymer powder of polyarylpiperidine is (1.5~2):4, and the molar ratio of the alkaline agent to the polymer of polyarylpiperidine is (2.5~3):

3.

6. The method for preparing a polymer film based on neopentane-crosslinked piperidine according to claim 2, characterized in that, The ketone reactant and the aromatic reactant are dissolved in a first organic solvent and reacted at -10℃ to 100℃ for 0.1 h to 96 h under the action of an acid catalyst. Then, a first precipitant is added to precipitate, wash and dry to obtain a polymer powder of polyarylpiperidine. And / or, dissolve the polyarylpiperidine polymer powder in a second organic solvent, add a first methylating agent and a basic agent to react, the reaction temperature range is 20℃~50℃, the reaction time is 24 h~72 h, then add a second precipitant to precipitate, wash and dry to obtain partially quaternized polymer powder.

7. The method for preparing a polymer film based on neopentane-crosslinked piperidine according to claim 2, characterized in that, The mass concentration of the partially quaternized polymer powder in the third organic solvent is 3 wt% to 10 wt%, the molar ratio of the neopentane crosslinking agent to the partially quaternized polymer powder is 1:(1.25~5), and the evaporation temperature range after the reaction with the addition of the neopentane crosslinking agent is 80℃ to 150℃.

8. The method for preparing a polymer film based on neopentane-crosslinked piperidine according to claim 2, characterized in that, The mass concentration of the partially quaternized neopentane crosslinked polymer film in the fourth organic solvent is 3 wt% to 10 wt%, the molar ratio of the second methylating agent to the partially quaternized neopentane crosslinked polymer film is (2~3):4, and the evaporation temperature range after adding the reaction with the second methylating agent is 80℃ to 150℃.

9. The method for preparing a polymer film based on neopentane-crosslinked piperidine according to claim 2, characterized in that, The second, third, and fourth organic solvents respectively include one or more of dimethyl sulfoxide, N-methylpyrrolidone, N-dimethylformamide, N,N-dimethylacetamide, chloroform, and tetrahydrofuran.

10. The application of a polymer membrane based on neopentane-crosslinked piperidine according to claim 1 or a polymer membrane based on neopentane-crosslinked piperidine prepared by the method according to any one of claims 2 to 9, characterized in that, The polymer membrane is used as an anion exchange membrane or as a binder for catalyst layers.

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