CN111313063A - A kind of preparation method of organic-MOF composite alkaline polymer electrolyte membrane and the membrane - Google Patents

Abstract

The invention belongs to an alkaline polymer electrolyte membrane; the invention also relates to a preparation method of the organic-MOF composite alkaline polymer electrolyte membrane, which comprises the following steps: (1) preparation of long alkyl side chain brominated polymer: (2) preparing a bromine-type organic-MOF composite alkaline membrane: the bromine-type organic-MOF composite alkaline membrane can be prepared by a method of firstly compounding and then functionalizing or a method of firstly functionalizing and then compounding.

Description

A kind of preparation method of organic-MOF composite alkaline polymer electrolyte membrane and the membrane

technical field

The invention belongs to the field of alkaline polymer electrolyte membrane; the invention also relates to the preparation of an alkaline polymer electrolyte membrane with strong water retention capacity, good chemical stability and high electrical conductivity.

Background technique

Alkaline polymer electrolyte membrane fuel cells (APEMFCs) with alkaline polymer membranes as solid electrolytes have fast cathode reaction kinetics and can use non-precious metals as electrocatalysts, which can effectively avoid the dendrite short circuit caused by salt deposition. and other advantages. Since it was first reported in 2005, it has become one of the research hotspots in the field of fuel cells. As one of the key materials for alkaline fuel cells, alkaline polymer electrolyte membranes have been widely studied and made great progress. Through molecular structure design, a continuous and obvious microscopic phase-separated structure was constructed in APEMs, a channel favorable for OH ^- transport was established, and the conductivity of the membrane was greatly improved, even exceeding that of the current commercial Nafion membrane. On this basis, the electrode structure was continued to be optimized and the test conditions were changed, and the performance of the alkaline fuel cell was also improved. However, the current working temperature of alkaline fuel cells is less than 80 °C, and under this condition, _CO2 in the air has a greater impact on the cell. The conductivity of the alkaline membrane and the alkaline ionomer inside the electrode will decrease by 2/3 or even greater when exposed to the air, which will directly lead to aggravation of the ohmic polarization of the fuel cell, and the battery performance will be greatly reduced. Studies have shown that the adsorption of _CO can be effectively reduced with increasing temperature (Huang et al., Sci China Chem, 2016, 360-369), however, when the operating temperature of the battery increases, the water pressure increases, and the conductivity of the alkaline film increases. Rate and stability are severely affected, decaying rapidly.

SUMMARY OF THE INVENTION

Aiming at the problem of performance degradation of alkaline membranes in high temperature and low humidity environment, the purpose of the present invention is to design and prepare a class of APEMs with strong water retention capacity, good chemical stability and high electrical conductivity, so that they can be used at temperatures >90°C or even higher. Use; characterize and test the physicochemical and electrochemical properties of such APEMs. The present invention obtains an organic polymer with good chemical stability and strong water retention capacity and a good compatibility with MOF by combining the size of MOF and the optimization and treatment of the film casting liquid through molecular structure design.

A class of APEMs with strong water retention capacity, good chemical stability and high electrical conductivity were prepared. Such basic membranes are composed of basic polymers and metal organic frameworks. Among them, the main chain of the basic polymer is polystyrene, poly(styrene-ethylene-butylene) block copolymer (SEBS), polyphenylene, polyether ether ketone, polyether ketone, polyphenylene ether, poly One of sulfone, polybenzimidazole or polyethersulfone; the positively charged functional group of the basic polymer is quaternary ammonium salt, guanidine salt, DABCO(1,4-diazabicyclo[2.2.2]octane) ), one or more of methylpyrrolidine or methylpiperidine; the positively charged functional group on the basic polymer is connected to the benzene ring on the main chain through an alkyl chain; MOF is MIL-101(Cr) , ZIF-1, ZIF-2, ZIF-3, ZIF-4, ZIF-5, ZIF-6, ZIF-7, ZIF-8, ZIF-9, ZIF-10, ZIF-11, ZIF-12, UiO One or more of -66.

A preparation of APEMs with strong water retention capacity, good chemical stability and high electrical conductivity includes the following steps:

(1) Preparation of long alkyl side chain brominated polymers

The preparation of long alkyl side chain brominated polymers involves two main steps: polystyrene, SEBS, polyphenylene, polyetheretherketone, polyetherketone, polyphenylene ether, polysulfone, polybenzimidazole or polyether Preparation of sulfone benzene ring para-acylalkyl bromides and preparation of long alkyl side chain brominated polymers.

a. The preparation process of polystyrene, SEBS, polyphenylene, polyether ether ketone, polyether ketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone benzene ring para-acyl alkyl bromide is: A certain mass of polystyrene, SEBS, polyphenylene, polyetheretherketone, polyetherketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone is dissolved in a certain volume of organic solvent A, at a certain temperature A certain volume of acid chloride alkyl bromide and a certain quality of catalyst are added, and the reaction is kept constant for a period of time at this temperature. Precipitate with solvent B, wash thoroughly, and then dry for use.

b. The preparation process of the long alkyl side chain brominated polymer is as follows: polystyrene, SEBS, polyphenylene, polyether ether ketone, polyether ketone, polyphenylene ether, polysulfone, polyphenylene prepared above of a certain quality are prepared Hemiimidazole or polyethersulfone benzene ring para-acyl alkyl bromide is dissolved in a certain volume of organic solvent C, adding a certain quality of reducing agent, or adding a certain volume of catalyst, and reacting at a certain temperature for a period of time to obtain a long-term Alkyl side chain brominated polymers. After returning to room temperature, poured into solvent D to precipitate long alkyl side chain brominated polymer, fully washed with solvent D and dried.

(2) Preparation of bromine-type organic-MOF composite alkaline membrane

The bromine-type organic-MOF composite alkaline membrane can be prepared by two methods: firstly compounding and then functionalizing, and firstly functionalizing and then compounding.

The process of preparing bromine-type organic-MOF composite alkaline membrane by first compounding and then functionalizing is as follows: dissolving the long alkyl side chain brominated polymer prepared in step (1) in a certain volume of solvent K, adding a certain mass of MOF material Or the dispersion solution of MOF and solvent K, after mixing evenly, pour it on a glass plate, volatilize the solvent at a certain temperature to obtain an organic-MOF composite film, and then put it in amine, guanidine, DABCO (1,4-diazabicycle) [2.2.2] One or more of (octane), methylpyrrolidine, and methylpiperidine are soaked at a certain temperature for functionalization to obtain a bromine-type organic-MOF composite alkaline membrane.

The process of preparing the bromine-type organic-MOF composite alkaline membrane by first functionalizing and then compounding is as follows: dissolving the long alkyl side chain brominated polymer prepared in step (1) in a certain volume of solvent K, adding a certain volume of amine, One or more of guanidine, DABCO (1,4-diazabicyclo[2.2.2]octane), methylpyrrolidine, and methylpiperidine are added to the long alkyl side chain brominated polymer In the solution, react at a certain temperature for a period of time to obtain a long alkyl side chain functionalized bromine type polymer solution, then add a certain quality of MOF material or a dispersion solution of MOF and solvent K, mix evenly and pour it on a glass plate , and volatilize the solvent at a certain temperature to obtain a bromine-type organic-MOF composite alkaline membrane.

(3) Preparation of hydroxyl-type long side chain functionalized membrane:

The bromine-type organic-MOF composite alkaline membrane obtained in step (2) is soaked in a potassium hydroxide or sodium hydroxide solution for a period of time at a certain temperature to obtain an organic-MOF composite alkaline polymer electrolyte membrane.

The preparation of above-mentioned organic-MOF composite alkaline polymer electrolyte membrane:

Step (1) During the preparation of polystyrene, SEBS, polyphenylene, polyether ether ketone, polyether ketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone benzene ring para-acyl alkyl bromide Described solvent A is carbon tetrachloride, chloroform, tetrahydrofuran, toluene, xylene; Described acid chloride alkyl bromide is 2-bromooctanoyl bromide, 2-bromooctanoyl chloride, 6-bromohexanoyl chloride, 2-bromohexanoyl chloride A kind of acid bromide, 4-bromobutyryl chloride, 2-bromobutyryl chloride, 2-bromobutyryl bromide, 3-bromopropionyl chloride, 2-bromopropionyl chloride; the catalyst is aluminum trichloride, tetrachloride One or more of tin, zinc chloride, phosphorus trichloride; Described solvent B is one or more of water, methanol, ethanol, ethyl acetate, ether, acetone;

Step (1) a Preparation process of polystyrene, SEBS, polyphenylene, polyether ether ketone, polyether ketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone benzene ring para-acyl alkyl bromide The mass ratio of polystyrene, SEBS, polyphenylene, polyetheretherketone, polyetherketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone to solvent A is 1:10～ 1:200g/mL (preferably 1:30～1:80g/mL, more preferably 1:40～1:60g/mL); the polystyrene, SEBS, polyphenylene, polyetheretherketone, The mass ratio of polyether ketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone to acid chloride alkyl bromide is 4:1 to 1:10 (preferably 1:1 to 1:8, In particular, 1:2 to 1:6); the quality of the polystyrene, SEBS, polyphenylene, polyetheretherketone, polyetherketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone is the same as The mass ratio of the catalyst is 4:1～1:4 (the optimal mass ratio is 3:1～1:2, especially 2:1～1.05:1), wherein the amount of the catalyst should be <2.5 times the polymer The amount of substance in the benzene ring;

Preparation of polystyrene, SEBS, polyphenylene, polyether ether ketone, polyether ketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone benzene ring para-acyl alkyl bromide in step (1) a In the process, when adding the acid chloride alkyl bromide and the catalyst, the solution temperature is <10 ° C to the solidification temperature of the solvent; in step (1), polystyrene, SEBS, polyphenylene, polyether ether ketone, polyether ketone, poly In the preparation process of phenyl ether, polysulfone, polybenzimidazole or polyethersulfone benzene ring para-acyl alkyl bromide, the method for adding acid chloride alkyl bromide is to add dropwise 2-5 times, and the drop rate is 0.3 -1mL/min; in step (1), polystyrene, SEBS, polyphenylene, polyether ether ketone, polyether ketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone phenyl ring para-acyl alkane In the preparation process of the base bromide, the method for adding the catalyst is to add in 2-5 times, wherein the first addition does not exceed 1/2 of the total amount; in step (1), polystyrene, SEBS, polyphenylene, In the preparation process of polyetheretherketone, polyetherketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone benzene ring para-acyl alkyl bromide, the pre-reaction is <10 ° C to the solidification temperature of the solvent is 0.5- 4h; the re-reaction temperature is room temperature-100°C; the reaction time is >2h; the drying conditions are natural drying or vacuum drying at <40°C;

In the preparation process of the long alkyl side chain brominated polymer in step (1)b, the solvent C is one or two of chloroform, 1,1,2,2-tetrachloroethane, tetrahydrofuran, toluene, and xylene. More than one species are mixed in proportion; the reducing agent is one of triethylsilane, trimethylsilane, tributylsilane, trihexylsilane, trioctylsilane, sodium borohydride, lithium borohydride, lithium aluminum hydride ; Described catalyst is one or both of trifluoroacetic acid and acetic acid; Described solvent D is one or more of water, methanol, ethanol and ethyl acetate;

The polystyrene, SEBS, polyphenylene, polyether ether ketone, polyether ketone, polyphenylene ether, polysulfone, polybenzimidazole described in the preparation process of step (1) b long alkyl side chain brominated polymer Or the mass ratio of the para-acyl alkyl bromide of the polyethersulfone benzene ring to the solvent C is 1:20 to 1:120 g/mL; the polystyrene, SEBS, polyphenylene, polyetheretherketone, polyether The mass ratio of ketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone benzene ring para-acyl alkyl bromide to the reducing agent is 4:1 to 1:10; the polystyrene, SEBS, The mass ratio of polyphenylene, polyetheretherketone, polyetherketone, polyphenylene ether, polysulfone, polybenzimidazole or polyethersulfone benzene ring para-acyl alkyl bromide to the volume of the catalyst is 2:1 to 1: 10;

In the preparation process of step (1)b long alkyl side chain brominated polymer, the reaction temperature is room temperature-100°C; the reaction time is >6h; the drying conditions are natural drying or vacuum drying at <40°C.

Step (2) Process of preparing bromine-type organic-MOF composite alkaline membrane The solvent K is tetrahydrofuran, xylene, toluene, chloroform, 1,1,2,2-tetrachloroethane, dimethylacetamide, dimethy One or more of methylformamide, N-methylpyrrolidone and dimethyl sulfoxide;

Step (2) The process of preparing bromine-type organic-MOF composite alkaline membrane The mass ratio of the polymer to the MOF is 200:1-1:2, preferably 50:1-1:1.5, especially 20 :1-1:1;

In the process of preparing the bromine-type organic-MOF composite alkaline membrane in step (2), when the mass ratio of the polymer to the MOF is greater than or equal to 10:1, the volume ratio of the polymer mass to the solvent K is 1:30～ 1:4 g/mL; the volume ratio of the mass of the MOF to the solvent K is 1:20 to 1:5 g/mL.

In the process of preparing the bromine-type organic-MOF composite alkaline membrane in step (2), when the mass ratio of the polymer to the MOF is less than 10:1, the volume ratio of the polymer mass to the solvent K is less than 1:30g/ mL; the volume ratio of the mass of the MOF to the solvent K is less than 1:30 g/mL.

The process of step (2) preparing the bromine-type organic-MOF composite alkaline membrane, the mixing mode is one or both of mechanical stirring, magnetic stirring, ultrasonic, and cell crushing;

The process of step (2) preparing the bromine-type organic-MOF composite alkaline film adopts a blast drying oven for the film casting step;

Step (2) in the process of first composite casting and then functional grouping, the casting temperature is room temperature -50°C; the casting time is 0.5-12h; the functional group soaking temperature is room temperature to 60°C; the soaking time is >4h;

Step (2) The mass ratio of the polymer to the amine, guanidine, DABCO methylpyrrolidine, and methylpiperidine in the process of first functionalizing and then compound casting is 3:1 to 1:10 g/mL; the reaction The temperature is from room temperature to 80°C; the reaction time is >4h; the temperature for preparing the film by volatilization of the solvent is 30 to 120°C;

The total concentration of potassium hydroxide or sodium hydroxide described in step (3) is 0.1-6 mol/L; the temperature of the alkali solution is room temperature to 60°C; the time of the alkali immersion film is >2h;

The preparation of the organic-MOF composite alkaline polymer electrolyte membrane of the present invention has the following advantages:

(1) In the preparation process of the long alkyl side chain polymer, the present invention can effectively avoid the occurrence of cross-linking reaction during the preparation of the long alkyl side chain polymer by controlling the conditions in the pre-reaction process and combining with the modulation of the re-reaction time, and can accurately control the long alkyl The amount and length of the base chain are further matched by the ratio of MOF and polymer, and finally an alkaline polymer electrolyte membrane with better performance is obtained;

(2) The prepared organic-MOF composite alkaline polymer electrolyte membrane has good water retention capacity;

(3) The prepared organic-MOF composite alkaline polymer electrolyte membrane has high ionic conductivity;

(4) The prepared organic-MOF composite alkaline polymer electrolyte membrane has good chemical stability in high temperature alkaline environment;

(5) The prepared long alkyl side chain functionalized alkaline polymer electrolyte membrane has good mechanical properties;

(6) The film casting process is simple and easy to mass produce;

Description of drawings

Fig. 1 is the preparation route diagram of the hexyl side chain brominated polymer in Example 1.

FIG. 2 is the hydrogen nuclear magnetic spectrum of BrKC ₆ SEBS and BrC ₆ SEBS in Example 1. FIG.

FIG. 3 is a curve of the electrical conductivity of the organic-MOF composite alkaline polymer electrolyte membrane in Example 1 as a function of temperature.

FIG. 4 shows the high temperature liquid loss of the organic-MOF composite alkaline polymer electrolyte membrane in Example 1. FIG.

FIG. 5 is the test result of thermodynamic dynamic analysis of the organic-MOF composite alkaline polymer electrolyte membrane in Example 1. FIG.

FIG. 6 is a graph showing the change of the conductivity value of the long alkyl side chain SEBS-based alkaline polymer electrolyte membrane at room temperature with the soaking time in a 1MKOH solution at 80°C.

Detailed ways

Example 1

2 g of SEBS was dissolved in 80 mL of chloroform, and 8 mL of 6-bromohexanoyl chloride and 1.8 g of anhydrous aluminum chloride were added twice in an ice-water bath (7° C.). The interval between the two times is 15min, the dropping rate of 6-bromohexanoyl chloride is 0.5mL/min, then the reaction is carried out under the condition of ice-water bath (<10℃) for 1h, and then the temperature is raised to 60℃ and the temperature is maintained by magnetic stirring. 24h. After the reaction solution returned to room temperature, it was poured into ethanol to precipitate an orange-yellow solid, which was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. The solid was then vacuum-dried at room temperature for 8 hours to obtain BrKC ₆ SEBS.

2 g of BrKC ₆ SEBS prepared above was dissolved in 100 mL of chloroform, 7.3 g of triethylsilane and 5 mL of trifluoroacetic acid were added in sequence at room temperature, the temperature was raised to 80 °C and the reaction was performed for 48 h to obtain a brown-red transparent solution. After returning to room temperature, ethanol was added. The precipitated solid was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. Then, the solid was dried under natural conditions to obtain a pale yellow solid powder named BrC ₆ SEBS.

0.5 g of BrC ₆ SEBS prepared above was dissolved in 2 mL of chloroform, then 18 mL of tetrachloroethane was added, and stirred at room temperature to obtain an orange-yellow transparent solution. Meanwhile, 0.1 g of ZIF-8 molecular sieve was ultrasonically dispersed in 15 mL of tetrachloroethane. Then, the ZIF-8/tetrachloroethane dispersion solution was slowly added dropwise to the solution of BrC ₆ SEBS while stirring, and the two were fully dispersed by a cell crusher, then poured onto a clean glass plate and placed in a blast drying oven The solvent was fully volatilized at 40°C to form a film, and an unfunctionalized organic-MOF composite film was obtained. The prepared membrane was soaked in trimethylamine aqueous solution at room temperature for 12h. The residual trimethylamine solution on the surface was thoroughly washed with water, and then the membrane was soaked in a 1M KOH solution at room temperature for 48 h to obtain an OH-type quaternary ammonium-type organic-MOF composite alkaline polymer electrolyte membrane. Finally it is characterized and tested.

The degree of substitution of acyl alkyl bromide on the benzene ring of the polymer and the degree of reduction of the acyl group were quantitatively characterized by Bruker ACIII 400, and its resonance frequency was 400.13 MHz. During the experiment, a small amount of the sample to be tested was dissolved in deuterated chloroform, and the ¹ H NMR spectrum of the sample was obtained on a nuclear magnetic resonance apparatus, and tetramethylsilane (TMS) was used as the internal standard. Figure 2 is the 1H NMR of BrKC6SEBS and BrC6SEBS. The substitution ratio of acylalkyl bromide can be seen from the characteristic peak positions of 2 and 1 and the hydrogen peak area ratio in 1H NMR in Fig. 2 . The substitution ratio of the acyl alkyl bromide of SEBS in this example is 0.24.

The ohmic impedance of the polymer-MOF composite alkaline polymer electrolyte membrane with SEBS as the main chain prepared above was tested by the AC impedance method, and then the conductivity value was calculated according to the calculation formula of the conductivity. The formula for calculating conductivity is as follows:

where σ is the conductivity of the membrane (S/cm), L is the distance between the SensorI and SensorII electrodes (cm), W is the width of the membrane (cm), T is the thickness of the membrane (cm), and R is the measured Impedance (Ω) of the membrane.

Before the test, cut the alkaline polymer electrolyte membrane into a rectangle of 0.5*4cm ² , fix it in the middle of the polytetrafluoroethylene mold, put the metal wire (silver wire or platinum wire) into the groove of the mold to lead out three electrodes, and then put the mold Put into deionized water and equilibrate at the set temperature for at least 30 min to measure the impedance of the membrane using AC impedance. The experimental instruments are SolartronAC1260 impedance analyzer and 1287 electrochemical workstation, and the scanning frequency range is 1-10 ⁶ Hz. The conductivity of the membrane is the average of multiple measured impedance calculations.

FIG. 3 is a curve of the electrical conductivity of the long alkyl chain alkaline polymer electrolyte membrane prepared in Example 1 as a function of temperature. In Figure 3, the abscissa is the temperature (°C), and the ordinate is the conductivity (mS cm ^-1 ); from the results in Figure 3, it can be seen that the conductivity of this type of film at room temperature is >20mS cm ^-1 , and at 90°C the conductivity The conductivity is close to 70 mS cm ^-1 .

The liquid loss of such organic-MOF composite alkaline polymer electrolyte membranes at high temperature was characterized by weight loss method. First, put the membrane to be tested in deionized water for 24 hours, take out and wipe off the surface liquid, and weigh. Then, it was dried in a vacuum drying oven at 100°C for 48 hours, and its weight was quickly measured. Then, the liquid loss of the polymer electrolyte membrane was calculated according to the calculation formula. The formula for calculating the fluid loss is as follows:

Loss%=(W _wet -W _dry )/W _wet *100

In the formula, W _wet is the mass (g) of the wet film, and W _dry is the mass (g) of the dry film.

FIG. 4 is a graph showing the comparison of the liquid loss of the alkaline polymer electrolyte membrane with the long alkyl side chain SEBS-based polymer and MOF composite prepared above and the liquid loss of the alkaline polymer electrolyte membrane without MOF. Figure 4 shows that the addition of MOF can effectively reduce the liquid loss of the alkaline polymer electrolyte membrane at high temperature, indicating that it has a good water retention capacity.

The dynamic thermodynamic properties of the membranes were analyzed and tested by DMA from TA. The heating rate was 3°C min ^-1 , and the temperature range was 100-210°C. The frequency was 1 Hz and the amplitude used was 20 μm.

Fig. 5 is the thermodynamic dynamic analysis test result of the alkaline polymer electrolyte membrane of the above-prepared long alkyl side chain SEBS-based polymer and MOF composite. Fig. 5 is the thermodynamic dynamic analysis test result of the long alkyl side chain SEBS-based alkaline polymer electrolyte membrane prepared above. It can be seen from Figure 5 that the storage modulus of this type of film is small, indicating that this type of film has better flexibility; at the same time, the glass transition temperature of this type of film is >180 ° C, indicating that this type of alkaline film has better flexibility. thermodynamic stability.

The chemical stability of such membranes was judged by analyzing the change of electrical conductivity in 1M KOH solution at 80°C. Figure 6 is a curve showing the change of the conductivity value of the long alkyl side chain SEBS-based alkaline polymer electrolyte membrane at room temperature with the soaking time in a 1M KOH solution at 80°C. It can be seen from Figure 6 that the electrical conductivity of this type of membrane hardly changed after 100h of treatment, indicating that this type of membrane has good chemical stability under the condition of 1M KOH solution at 80 °C.

Example 2

2 g of SEBS was dissolved in 80 mL of chloroform, and 8 mL of 6-bromohexanoyl chloride and 1.8 g of anhydrous aluminum chloride were added twice in an ice-water bath (7° C.). The interval between the two times is 15min, the dropping rate of 6-bromohexanoyl chloride is 0.5mL/min, then the reaction is carried out under the condition of ice-water bath (<10℃) for 1h, and then the temperature is raised to 60℃ and the temperature is maintained by magnetic stirring. 24h. After the reaction solution returned to room temperature, it was poured into ethanol to precipitate an orange-yellow solid, which was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed with ethanol. The solid was then vacuum-dried at room temperature for 8 hours to obtain BrKC ₆ SEBS, The degree of acylation was 0.24.

2 g of BrKC ₆ SEBS prepared above was dissolved in 100 mL of chloroform, 7.3 g of triethylsilane and 5 mL of trifluoroacetic acid were added in sequence at room temperature, the temperature was raised to 80 °C and the reaction was performed for 48 h to obtain a brown-red transparent solution. After returning to room temperature, ethanol was added. The precipitated solid was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. Then, the solid was dried under natural conditions to obtain a pale yellow solid powder named BrC ₆ SEBS.

0.5 g of BrC ₆ SEBS prepared above was dissolved in 2 mL of chloroform, then 8 mL of tetrachloroethane was added, and stirred at room temperature to obtain an orange-yellow transparent solution. At the same time, 0.025 g of ZIF-11 molecular sieve was ultrasonically dispersed in 0.5 mL of tetrachloroethane. Then, the ZIF-11/tetrachloroethane dispersion solution was slowly added dropwise to the solution of BrC ₆ SEBS while stirring, and the two were fully dispersed by a cell crusher. The solvent was fully volatilized at 40°C to form a film, and an unfunctionalized organic-MOF composite film was obtained. The prepared membrane was soaked in trimethylamine aqueous solution at room temperature for 12h. The residual trimethylamine solution on the surface was thoroughly washed with water, and then the membrane was soaked in a 1M KOH solution at room temperature for 48 h to obtain an OH-type quaternary ammonium-type organic-MOF composite alkaline polymer electrolyte membrane. The liquid loss of the obtained organic-MOF alkaline polymer electrolyte membrane is close to 50%, which is weaker than the water retention capacity of the membrane in Example 1.

Example 3

2 g of SEBS was dissolved in 80 mL of chloroform, and 8 mL of 6-bromohexanoyl chloride and 1.8 g of anhydrous aluminum chloride were added twice in an ice-water bath (7° C.). The interval between the two times is 15min, the dropping rate of 6-bromohexanoyl chloride is 0.5mL/min, and then the reaction is carried out under the condition of ice-water bath (<10℃) for 1h, then the temperature is raised to 70℃ and the temperature is maintained by magnetic stirring. 20h. After the reaction solution returned to room temperature, it was poured into ethanol to precipitate an orange-yellow solid, which was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed with ethanol. The solid was then vacuum-dried at room temperature for 8 hours to obtain BrKC ₆ SEBS, The degree of acylation was 0.25.

2 g of BrKC ₆ SEBS prepared above was dissolved in 100 mL of chloroform, 7.3 g of triethylsilane and 5 mL of trifluoroacetic acid were added in sequence at room temperature, the temperature was raised to 80 °C and the reaction was performed for 48 h to obtain a brown-red transparent solution. After returning to room temperature, ethanol was added. The precipitated solid was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. Then, the solid was dried under natural conditions to obtain a pale yellow solid powder named BrC ₆ SEBS.

0.5 g of BrC ₆ SEBS prepared above was dissolved in 2 mL of chloroform, then 8 mL of tetrachloroethane was added, and stirred at room temperature to obtain an orange-yellow transparent solution. Meanwhile, 0.05 g of ZIF-6 molecular sieve was ultrasonically dispersed in 10 mL of tetrachloroethane. Then, the ZIF-6/tetrachloroethane dispersion solution was slowly added dropwise to the solution of BrC ₆ SEBS while stirring, and the two were fully dispersed by a cell crusher. The solvent was fully volatilized at 40°C to form a film, and an unfunctionalized organic-MOF composite film was obtained. The prepared membrane was soaked in trimethylamine aqueous solution at room temperature for 12h. The residual trimethylamine solution on the surface was thoroughly washed with water, and then the membrane was soaked in a 1M KOH solution at room temperature for 48 h to obtain an OH-type quaternary ammonium-type organic-MOF composite alkaline polymer electrolyte membrane. The conductivity of the resulting membrane reached 82 mS cm ^-1 at 100°C with a fluid loss of 46%.

Example 4

2 g of SEBS was dissolved in 80 mL of chloroform, and 8 mL of 6-bromohexanoyl chloride and 1.8 g of anhydrous aluminum chloride were added twice in an ice-water bath (7° C.). The interval between the two times is 15min, the dropping rate of 6-bromohexanoyl chloride is 0.5mL/min, and then the reaction is carried out under the condition of ice-water bath (<10℃) for 1h, then the temperature is raised to 70℃ and the temperature is maintained by magnetic stirring. 20h. After the reaction solution returned to room temperature, it was poured into ethanol to precipitate an orange-yellow solid, which was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed with ethanol. The solid was then vacuum-dried at room temperature for 8 hours to obtain BrKC ₆ SEBS, The degree of acylation was 0.25.

2 g of BrKC ₆ SEBS prepared above was dissolved in 100 mL of chloroform, 7.3 g of triethylsilane and 5 mL of trifluoroacetic acid were added in sequence at room temperature, the temperature was raised to 80 °C and the reaction was performed for 48 h to obtain a brown-red transparent solution. After returning to room temperature, ethanol was added. The precipitated solid was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. Then, the solid was dried under natural conditions to obtain a pale yellow solid powder named BrC ₆ SEBS.

0.5 g of BrC ₆ SEBS prepared above was dissolved in 2 mL of chloroform, then 8 mL of tetrachloroethane was added, and stirred at room temperature to obtain an orange-yellow transparent solution. At the same time, 0.05 g of ZIF-12 molecular sieve was ultrasonically dispersed in 5 mL of tetrachloroethane. Then, the ZIF-12/tetrachloroethane dispersion solution was slowly added dropwise to the solution of BrC ₆ SEBS while stirring, and the two were fully dispersed by a cell crusher. The solvent was fully volatilized at 40°C to form a film, and an unfunctionalized organic-MOF composite film was obtained. The prepared membrane was soaked in trimethylamine aqueous solution at room temperature for 12h. The residual trimethylamine solution on the surface was thoroughly washed with water, and then the membrane was soaked in a 1M KOH solution at room temperature for 48 h to obtain an OH-type quaternary ammonium-type organic-MOF composite alkaline polymer electrolyte membrane. The resulting membrane had a fluid loss of 42%.

Example 5

2 g of SEBS was dissolved in 80 mL of chloroform, and 8 mL of 6-bromohexanoyl chloride and 1.8 g of anhydrous aluminum chloride were added twice in an ice-water bath (7° C.). The interval between the two times is 15min, the dropping rate of 6-bromohexanoyl chloride is 0.5mL/min, and then the reaction is carried out under the condition of ice-water bath (<10℃) for 1h, then the temperature is raised to 70℃ and the temperature is maintained by magnetic stirring. 20h. After the reaction solution returned to room temperature, it was poured into ethanol to precipitate an orange-yellow solid, which was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. Then the solid was vacuum-dried at room temperature for 8 hours to obtain BrKC6SEBS, which was acylated. The degree is 0.25.

Dissolve 2 g of the BrKC6SEBS prepared above in 100 mL of chloroform, add 7.3 g of triethylsilane and 5 mL of trifluoroacetic acid in sequence at room temperature, and heat up to 80 °C and react for 48 h to obtain a brown-red transparent solution. After returning to room temperature, a solid was precipitated with ethanol , dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. Then, the solid was dried under natural conditions to obtain a light yellow solid powder, named BrC6SEBS.

Dissolve 0.5 g of BrC6SEBS prepared above in 2 mL of chloroform, then add 8 mL of tetrachloroethane, stir at room temperature to obtain an orange-yellow transparent solution, add 5 mL of methylpyrrolidine to it, and react at 80 °C for 12 h under reflux to obtain methyl Pyrrolidine functionalized polymer solution. Then 0.05 g of ZIF-11 molecular sieves were ultrasonically dispersed in 1 mL of tetrachloroethane. Then, the ZIF-11/tetrachloroethane dispersion solution was slowly added dropwise to the methylpyrrolidine functionalized polymer solution while stirring, and the two were fully dispersed by a cell crusher, and then poured onto a clean glass plate. Heating at 40 °C for 30 min in a blast drying oven and then raising the temperature to 80 °C to fully volatilize the solvent to form a film to obtain a methylpyrrolidine functionalized organic-MOF composite film. Then, the membrane was soaked in 1M KOH solution at room temperature for 48 h to obtain an OH-type pyrrolidine functionalized organic-MOF composite alkaline polymer electrolyte membrane. The resulting membrane had a fluid loss of 42%.

Example 6

2 g of SEBS was dissolved in 80 mL of chloroform, and 8 mL of 6-bromohexanoyl chloride and 1.8 g of anhydrous aluminum chloride were added twice in an ice-water bath (7° C.). The interval between the two times is 15min, the dropping rate of 6-bromohexanoyl chloride is 0.5mL/min, and then the reaction is carried out under the condition of ice-water bath (<10℃) for 1h, then the temperature is raised to 70℃ and the temperature is maintained by magnetic stirring. 20h. After the reaction solution returned to room temperature, it was poured into ethanol to precipitate an orange-yellow solid, which was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. Then the solid was vacuum-dried at room temperature for 8 hours to obtain BrKC6SEBS, which was acylated. The degree is 0.25.

Dissolve 2 g of the BrKC6SEBS prepared above in 100 mL of chloroform, add 7.3 g of triethylsilane and 5 mL of trifluoroacetic acid in sequence at room temperature, and heat up to 80 °C and react for 48 h to obtain a brown-red transparent solution. After returning to room temperature, a solid was precipitated with ethanol , dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. Then, the solid was dried under natural conditions to obtain a light yellow solid powder, named BrC6SEBS.

Dissolve 0.5 g of BrC6SEBS prepared above in 2 mL of chloroform, then add 28 mL of tetrachloroethane, stir at room temperature to obtain an orange-yellow transparent solution, add 4 mL of methyl piperidine to it, and react at 80 °C for 12 h under reflux to obtain methyl Piperidine functionalized polymer solution. Then 0.5 g of ZIF-8 molecular sieves were ultrasonically dispersed in 50 mL of tetrachloroethane. Then, the ZIF-8/tetrachloroethane dispersion solution was slowly added dropwise to the methylpiperidine functionalized polymer solution while stirring, and the two were fully dispersed by a cell crusher, and then poured onto a clean glass plate. Heating at 40 °C for 30 min in a blast drying oven and then raising the temperature to 80 °C to fully volatilize the solvent to form a film to obtain a methylpyrrolidine functionalized organic-MOF composite film. Then, the membrane was soaked in 1M KOH solution at room temperature for 48 h to obtain an OH-type piperidine functionalized organic-MOF composite alkaline polymer electrolyte membrane. The resulting membrane had a fluid loss of 12%.

Comparative Example 1

BrC6SEBS was prepared according to the method of Example 6. Then, 0.5 g of BrC6SEBS prepared above was dissolved in 2 mL of chloroform, then 28 mL of tetrachloroethane was added, and stirred at room temperature to obtain an orange-yellow transparent solution, to which was added 4 mL of methyl piperidine, and reacted at 80 °C for 12 h under reflux to obtain methyl methacrylate. Piperidine functionalized polymer solution. Then 0.5 g of ZIF-8 molecular sieves were ultrasonically dispersed in 14 mL of tetrachloroethane. Then, the ZIF-8/tetrachloroethane dispersion solution was slowly added dropwise into the methylpiperidine functionalized polymer solution while stirring. After 5 hours of dispersion with a cell crusher, the MOF was still not well dispersed in the polymer solution. , after the film was cast, white large particles of MOF were deposited on the surface of the film.

Comparative Example 2

2 g of SEBS was dissolved in 80 mL of chloroform, and 8 mL of 6-bromohexanoyl chloride and 1.8 g of anhydrous aluminum chloride were added twice in an ice-water bath (7° C.). The interval between the two times is 15min, the dropping rate of 6-bromohexanoyl chloride is 0.5mL/min, and then the reaction is carried out under the condition of ice-water bath (<10℃) for 1h, then the temperature is raised to 70℃ and the temperature is maintained by magnetic stirring. 20h. After the reaction solution returned to room temperature, it was poured into ethanol to precipitate an orange-yellow solid, which was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed with ethanol. The solid was then vacuum-dried at room temperature for 8 hours to obtain BrKC ₆ SEBS, The degree of acylation was 0.25.

2 g of BrKC ₆ SEBS prepared above was dissolved in 100 mL of chloroform, 7.3 g of triethylsilane and 5 mL of trifluoroacetic acid were added in sequence at room temperature, the temperature was raised to 80 °C and the reaction was performed for 48 h to obtain a brown-red transparent solution. After returning to room temperature, ethanol was added. The precipitated solid was dissolved in tetrahydrofuran and then precipitated with ethanol. This process was repeated three times and then washed thoroughly with ethanol. Then, the solid was dried under natural conditions to obtain a pale yellow solid powder named BrC ₆ SEBS.

Dissolve 0.5 g of the above-prepared BrC ₆ SEBS in 2 mL of chloroform, then add 8 mL of tetrachloroethane, and stir at room temperature to obtain an orange-yellow transparent solution, which is directly poured onto a clean glass plate and placed in a blast drying oven at 40°C Fully volatilize the solvent to form a film, and soak the prepared film in an aqueous solution of trimethylamine for 12 h at room temperature. The residual trimethylamine solution on the surface was thoroughly washed with water, and then the membrane was soaked in a 1M KOH solution at room temperature for 48 h to obtain an OH-type quaternary ammonium-type organic-MOF composite alkaline polymer electrolyte membrane. The resulting membrane had a fluid loss of nearly 87% (see data in Figure 4).

Claims (10)

1. a preparation method of organic-MOF composite alkaline polymer electrolyte membrane, comprises the following steps: (1) preparation of long alkyl side chain brominated polymer: A. Dissolving the long alkyl polymer in the organic solvent A, adding the acid chloride alkyl bromide and the catalyst, after the pre-reaction, the constant temperature reaction; then separating out with the solvent B, washing and drying to obtain the para-acyl alkyl bromide; The temperature of the pre-reaction solution is <10°C to the solidification temperature of the solvent; the pre-reaction time is 0.5-4h; The amount of the material of the catalyst should be <2.5 times the amount of the material of the benzene ring in the polymer; The method for adding the acid chloride alkyl bromide is to add dropwise in stages, and repeat mixing at the interval of each dropping process, and the dropping rate is 0.3-1mL/min; the method for adding the catalyst is to divide 2-5 times Add, wherein the amount added for the first time does not exceed 1/2 of the total; b, dissolving the para-acyl alkyl bromide obtained in step a in organic solvent C, adding a reducing agent, without adding or adding a catalyst, after the reaction, a long alkyl side chain brominated polymer is obtained; after cooling to room temperature, pour the Enter solvent D and separate out, after washing and drying, long alkyl side chain brominated polymer is obtained; (2) Preparation of bromine-type organic-MOF composite alkaline membrane Bromine-type organic-MOF composite alkaline membrane can be prepared by two methods: firstly compounding and then functionalizing, or firstly functionalizing and then compounding. 2. according to the described preparation method of claim 1, it is characterized in that: The long alkyl polymer described in step 1) a is polystyrene, SEBS, polyphenylene, polyether ether ketone, polyether ketone, polyphenylene ether, polysulfone, polybenzimidazole, polyethersulfone benzene ring. one or more of them. 3. according to the described preparation method of claim 1, it is characterized in that: The organic solvent A is one or more of carbon tetrachloride, chloroform, tetrachloroethane, tetrahydrofuran, toluene, and xylene; The acid chloride alkyl bromide is 2-bromooctanoyl bromide, 2-bromooctanoyl chloride, 6-bromohexanoyl chloride, 2-bromohexanoyl bromide, 4-bromobutyryl chloride, 2-bromobutyryl chloride, 2-bromobutanoyl chloride A kind of in acid bromide, 3-bromopropionyl chloride, 2-bromopropionyl chloride; The catalyst is one or more of aluminum trichloride, tin tetrachloride, zinc chloride, and phosphorus trichloride; The solvent B is one or more of water, methanol, ethanol, isopropanol, ethyl acetate, ether, and acetone. 4. according to the described preparation method of claim 1, it is characterized in that: The mass ratio of the long alkyl polymer to the volume of solvent A is 1:10-1:200g/mL (preferably 1:30-1:80g/mL, more preferably 1:40-1:60g/mL). mL); the volume ratio of the mass of the long alkyl polymer to the acid chloride alkyl bromide is 4:1 to 1:10 (preferably 1:1 to 1:8, especially 1:2 to 1:6 ); the mass ratio of the long alkyl polymer to the catalyst is 4:1 to 1:4 (preferable mass ratio is 3:1 to 1:2, especially 2:1 to 1.05:1). 5. according to the described preparation method of claim 1, it is characterized in that: In step 1)a, the re-constant reaction temperature is room temperature-100°C; the reaction time is >2h; and the drying condition is natural drying or vacuum drying at <40°C. 6. according to the described preparation method of claim 1, it is characterized in that: The solvent C described in step (1)b is one or more of chloroform, 1,1,2,2-tetrachloroethane, tetrahydrofuran, toluene, and xylene mixed in proportion; the reducing agent is triethyl a kind of silane, trimethylsilane, tributylsilane, trihexylsilane, trioctylsilane, sodium borohydride, lithium borohydride, lithium aluminum hydride; the catalyst is a kind of trifluoroacetic acid and acetic acid Or two kinds; Described solvent D is one or more in water, methanol, ethanol, ethyl acetate; Step (1) b The mass ratio of the para-acyl alkyl bromide of the long alkyl polymer to the volume ratio of the solvent C is 1:20 to 1:120 g/mL; the mass and reduction of the long alkyl polymer acyl alkyl bromide The mass ratio of the catalyst is 4:1 to 1:10; the mass ratio of the para-acylalkyl bromide of the long alkyl polymer to the volume of the catalyst is 2:1 to 1:10; In the preparation process of step (1)b long alkyl side chain brominated polymer, the reaction temperature is room temperature-100°C; the reaction time is >6h; the drying conditions are natural drying or vacuum drying at <40°C. 7. according to the described preparation method of claim 1, it is characterized in that: In step (2), the process of preparing the bromine-type organic-MOF composite alkaline membrane by first compounding and then functionalizing is as follows: dissolving the long alkyl side chain brominated polymer prepared in step (1) in solvent K, adding MOF material Or the dispersion solution of MOF and solvent K, after mixing evenly, pour it on the plate, volatilize the solvent to obtain the organic-MOF composite film, and then put it in amine, guanidine, DABCO (1,4-diazabicyclo[2.2.2] Octane), methyl pyrrolidine, methyl piperidine in one or more kinds of solutions soaked in the functional group to obtain bromine-type organic-MOF composite alkaline membrane; The process of preparing bromine-type organic-MOF composite alkaline membrane by functional grouping first and then compounding is as follows: dissolving the long alkyl side chain brominated polymer prepared in step (1) in solvent K, adding amine, guanidine, DABCO (1, One or more of 4-diazabicyclo[2.2.2]octane), methylpyrrolidine and methylpiperidine are added to the solution of the long alkyl side chain brominated polymer, react, The long alkyl side chain functionalized bromine-type polymer solution is obtained, then the MOF material or the dispersion solution of MOF and solvent K is added, mixed evenly and then poured onto a flat plate, and the solvent is volatilized to obtain a bromine-type organic-MOF composite alkaline membrane. 8. according to the described preparation method of claim 7, it is characterized in that: The MOF is MIL-101(Cr), ZIF-1, ZIF-2, ZIF-3, ZIF-4, ZIF-5, ZIF-6, ZIF-7, ZIF-8, ZIF-9, ZIF-10 , one or more of ZIF-11, ZIF-12, UiO-66, preferably MIL-101(Cr), ZIF-2, ZIF-3, ZIF-6, ZIF-8, ZIF-10 , one or more of ZIF-11, ZIF-12, UiO-66; The solvent K is tetrahydrofuran, xylene, toluene, chloroform, 1,1,2,2-tetrachloroethane, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, dimethylmethylene One or more of sulfones; The mass ratio of the polymer to the MOF is 200:1-1:2, preferably 50:1-1:1.5, especially 20:1-1:1; When the mass ratio of the polymer mass to the MOF is ≥10:1, the volume ratio of the polymer mass to the solvent K is 1:30 to 1:4 g/mL; the volume ratio of the MOF mass to the solvent K is 1:30-1:4 g/mL; 1:20～1:5g/mL; When the mass ratio of the polymer to the MOF is <10:1, the volume ratio of the polymer mass to the solvent K is <1:30g/mL; the mass ratio of the MOF to the solvent K is <1:30g /mL; The mixing method is one or more of mechanical stirring, magnetic stirring, ultrasound, and cell crushing, preferably one or both of ultrasound or cell crushing; The film casting step adopts a blast drying oven; Step (2) in the process of first composite casting and then functional grouping, the casting temperature is room temperature -50°C; the casting time is 0.5-12h; the functional group soaking temperature is room temperature to 60°C; the soaking time is >4h; Step (2) The volume ratio of the mass of the polymer to the amine, guanidine, DABCO, methylpyrrolidine, and methylpiperidine in the composite film casting process is 3:1 to 1:10 g/mL; The reaction temperature is room temperature to 80°C; the reaction time is >4h; the temperature for preparing the film by volatilizing the solvent is 30-120°C. 9. according to the described preparation method of claim 1, it is characterized in that: Preparation of Hydroxide Type Long Side Chain Functionalized Film: Immerse the long alkyl side chain functionalized bromine type polymer film obtained in step (2) in potassium hydroxide or sodium hydroxide solution to obtain long alkyl side chains Chain-functionalized alkaline polymer electrolyte membrane The total concentration of the potassium hydroxide or sodium hydroxide is 0.1-6 mol/L; the temperature of the alkali solution is room temperature to 60° C.; the time of the alkali immersion film is more than 2h. 10. An organic-MOF composite alkaline polymer electrolyte membrane prepared by the preparation method of any one of claims 1-9.

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