Preparation method of ultrathin enhanced composite proton exchange membrane
阅读说明：本技术 一种超薄增强型复合质子交换膜的制备方法 (Preparation method of ultrathin enhanced composite proton exchange membrane ) 是由 何伟东 张曹朦 董运发 刘远鹏 袁博韬 韩杰才 于 2021-09-02 设计创作，主要内容包括：本发明公开了一种超薄增强型复合质子交换膜的制备方法,属于燃料电池隔膜制备技术领域。本发明解决了现有提高质子交换膜机械性能的方法,无法同时保证薄膜电导率、耐久性以及界面相容性等问题。本发明在已有研究的超支化聚合物粘合剂的基础上,再加入一种烯烃进行亲电加成,引入了聚合物长链,增加了聚合物的机械强度,应用其制备复合质子交换膜有效提高超薄质子交换膜的机械性能的同时,通过亲水相提高保湿性,以及分子链上的基团电离来提高隔膜的电导率,保证了质子膜的电导率。(The invention discloses a preparation method of an ultrathin reinforced composite proton exchange membrane, belonging to the technical field of preparation of fuel cell membranes. The invention solves the problems that the conductivity, durability, interface compatibility and the like of the film cannot be simultaneously ensured by the conventional method for improving the mechanical property of the proton exchange membrane. According to the invention, on the basis of the existing researched hyperbranched polymer adhesive, olefin is added for electrophilic addition, a polymer long chain is introduced, the mechanical strength of the polymer is increased, the mechanical performance of the ultrathin proton exchange membrane is effectively improved by applying the hyperbranched polymer adhesive to prepare the composite proton exchange membrane, the moisture retention is improved by a hydrophilic phase, and the electrical conductivity of the membrane is improved by group ionization on the molecular chain, so that the electrical conductivity of the proton membrane is ensured.)
1. A hyperbranched polymer having the structural formula:
2. the method of claim 1, wherein the method comprises: pentaerythritol tetraacrylate, ethylene glycol diacrylate-200 and dopamine hydrochloride are used as raw materials to prepare the compound through Michael addition reaction.
3. The method for preparing hyperbranched polymer according to claim 2, wherein the method comprises the following specific steps:
mixing pentaerythritol tetraacrylate, ethylene glycol diacrylate-200, dopamine hydrochloride and a solvent, stirring until a system is clear, then dropwise adding triethylamine into the system until the pH value of the system is 8, placing the system in the dark, stirring for 3 hours at a constant temperature of 80 ℃, performing suction filtration to obtain a clear solution, precipitating the clear solution by using methyl tert-butyl ether, performing suction filtration again to discharge filtrate, repeatedly using the methyl tert-butyl ether to precipitate the filtrate until no precipitate is generated, combining precipitated products and drying to obtain the hyperbranched polymer.
4. The preparation method of a hyperbranched polymer as claimed in claim 3, wherein the mass percentages of pentaerythritol tetraacrylate, ethylene glycol diacrylate-200, dopamine hydrochloride and dimethyl sulfoxide in the system are (4% -5%): (5-7%): (10-12%): (76% to 81%).
5. The method of claim 3, wherein the solvent is dimethyl sulfoxide.
6. A method of preparing a proton exchange membrane using the hyperbranched polymer of claim 1, the method comprising the steps of:
step 1, dissolving a main material in a solvent to obtain a uniform main material solution;
step 2, dispersing the hyperbranched polymer in a solvent to obtain a uniform hyperbranched polymer solution;
step 3, mixing the main material solution and the hyperbranched polymer solution obtained in the step, adding a dispersant stannous pyrophosphate, and stirring and mixing to obtain a membrane preparation solution;
the mass of the hyperbranched polymer in the membrane preparation liquid accounts for 1-20% of the total mass of the hyperbranched polymer and the main material, and the addition amount of the dispersant stannous pyrophosphate is 0.1-1% of the mass of the mixed solution;
and 4, preparing a membrane by using the membrane preparation liquid obtained in the step 3, and evaporating the solvent at 80 ℃ to form the enhanced composite proton exchange membrane with the thickness of 10-15 microns.
7. The method of claim 6, wherein the solvent is selected from the group consisting of dimethylsulfoxide, N-methylpyrrolidone, and tetrahydrofuran.
8. The method for preparing a proton exchange membrane using hyperbranched polymer as claimed in claim 6, wherein the host material is any one of perfluorosulfonic acid resin, polybenzimidazole, sulfonated polyether ether ketone, and polyphosphazene, wherein the mass fraction of solute in the host material solution is 5% to 20%, and the equivalent weight of perfluorosulfonic acid resin is 1000.
9. The method for preparing a proton exchange membrane using hyperbranched polymer as claimed in claim 6, wherein the mass fraction of solute in the hyperbranched polymer solution is 0.5-10%.
10. A method for purifying and protonating a reinforced composite proton exchange membrane obtained by the method of claim 6, comprising: firstly, the enhanced composite proton exchange membrane is soaked in hydrogen peroxide solution with the mass fraction of 3% -5% at the temperature of 70-90 ℃ for 1H, is washed by deionized water to remove the hydrogen peroxide, and is placed in H with the concentration of 0.4-2 mol/L2SO4Soaking in the solution for 1H, soaking with deionized water for 0.5-2H, changing water for at least 3 times, and washing off H2SO4And (4) dissolving to obtain the purified and protonated proton exchange membrane.
Technical Field
The invention relates to a preparation method of an ultrathin reinforced composite proton exchange membrane, belonging to the technical field of preparation of fuel cell membranes.
Background
Fuel cells have been developed to date, and Proton Exchange Membrane Fuel Cells (PEMFCs) are one of the most widely used fuel cells. Perfluorosulfonic acid membranes (PFSAs) have been widely studied and used because of their high mechanical strength, good chemical stability, good conductivity under humid conditions, and the like. In the initial stage of research, mechanical properties of proton exchange membranes are not the focus of research, and as research shows that thinner membranes can reduce membrane resistance and improve water management, but mechanical properties of membranes are poor, so that improvement of mechanical properties of membranes has become a focus of current research while the membranes are being made thinner.
At present, physical enhancement is mainly adopted for improving the mechanical property of the membrane, a PFSA membrane is enhanced by using a polymer with good mechanical property, and Polytetrafluoroethylene (PTFE) is the most used polymer at present. The common preparation method is to immerse the perfluorosulfonic acid resin (PFSA) in the expanded polytetrafluoroethylene, so as to effectively improve the mechanical strength and dimensional stability of the membrane while reducing the thickness of the membrane. Although the mechanical property of the proton exchange membrane can be effectively improved, the soaking is difficult to achieve an ideal state, the swelling ratio of two phase interfaces is different, the problems of interface dissociation and the like can occur in the using process, and the durability of the membrane electrode cannot be ensured. Besides ensuring good mechanical properties, the proton conductivity of the proton exchange membrane is also an important measure. Although the mechanical property of the composite membrane prepared by physical enhancement can be greatly improved, the electrical conductivity of the composite membrane is often lower than that of a pure membrane because an inert matrix material which is not hydrophilic, even hydrophobic and can not conduct protons is introduced. Therefore, it is necessary to provide a method for preparing a proton exchange membrane which can improve the mechanical properties of the membrane while ensuring the proton conductivity of the membrane.
Disclosure of Invention
The invention provides a hyperbranched polymer, a preparation method thereof and application thereof in a proton exchange membrane, aiming at solving the problems that the existing method for improving the mechanical property of the proton exchange membrane can not simultaneously ensure the conductivity, durability, interface compatibility and the like of a film.
The technical scheme of the invention is as follows:
a hyperbranched polymer having the structural formula:
the degree of branching DB is from 0.3 to 0.6, the average molecular weight is 7000 and the molecular weight Distribution (DPI) is 1.4.
The preparation method of the hyperbranched polymer comprises the following steps: the compound is prepared from pentaerythritol tetraacrylate, ethylene glycol diacrylate-200 and dopamine hydrochloride as raw materials through Michael addition reaction, and the synthetic route is as follows:
further limiting, the specific operation process of the method is as follows: mixing pentaerythritol tetraacrylate, ethylene glycol diacrylate-200, dopamine hydrochloride and dimethyl sulfoxide, stirring until a system is clear, then dropwise adding triethylamine into the system until the pH value of the system is 8, placing the system under a dark condition, stirring for 3 hours at a constant temperature of 80 ℃, performing suction filtration to obtain a clear solution, precipitating the clear solution by using methyl tert-butyl ether, performing suction filtration again to discharge filtrate, repeatedly using the methyl tert-butyl ether to precipitate the filtrate until no precipitate is generated, combining precipitated products and drying to obtain the hyperbranched polymer.
Further limiting, the mass percentages of pentaerythritol tetraacrylate, ethylene glycol diacrylate-200, dopamine hydrochloride and dimethyl sulfoxide in the system are (4-5%): (5-7%): (10-12%): (76% to 81%).
The method for preparing the proton exchange membrane by using the hyperbranched polymer comprises the following steps:
step 1, dissolving a main material in a solvent to obtain a uniform main material solution;
step 2, dispersing the hyperbranched polymer in a solvent to obtain a uniform hyperbranched polymer solution;
step 3, mixing the main material solution and the hyperbranched polymer solution obtained in the step, adding a dispersant stannous pyrophosphate, and stirring and mixing to obtain a membrane preparation solution;
the mass of the hyperbranched polymer in the membrane preparation liquid accounts for 1-20% of the total mass of the hyperbranched polymer and the fluorosulfonic acid resin, and the addition amount of the dispersant stannous pyrophosphate is 0.5-1% of the mass of the mixed solution;
and 4, preparing a membrane by using the membrane preparation liquid obtained in the step 3, and evaporating the solvent at 80 ℃ to form the enhanced composite proton exchange membrane with the thickness of 10-15 microns.
Further defined, the solvent is dimethyl sulfoxide or tetrahydrofuran.
Further limiting, the mass fraction of the solute of the hyperbranched polymer solution is 0.5-10%.
Further limited, the main material is any one of perfluorosulfonic acid resin, polybenzimidazole, sulfonated polyether ether ketone and polyphosphazene.
Further limiting, the mass fraction of the solute of the main body material solution is 5-20%.
More particularly, the equivalent weight of the perfluorosulfonic acid resin is 1000.
More specifically, when the host resin is replaced by polybenzimidazole, the polybenzimidazole is subjected to acid doping by methods such as crosslinking and micropore permeation after film formation.
More particularly, the acid includes, but is not limited to, sulfuric acid, phosphoric acid.
The method for purifying and protonating the enhanced composite proton exchange membrane obtained by the method comprises the following steps: soaking the enhanced composite proton exchange membrane in hydrogen peroxide solution with the mass fraction of 3-5% at 70-90 ℃ for 1H, washing with deionized water for many times to remove residual hydrogen peroxide, and then using 0.4-2 mol/L H2SO4Soaking in the solution for 1H, then soaking with deionized water for 0.5-2H, changing water for at least 3 times, and washing off H2SO4And (4) dissolving to obtain the purified and protonated proton exchange membrane.
The invention has the following beneficial effects: according to the invention, on the basis of the existing researched hyperbranched polymer adhesive, olefin is added for electrophilic addition, a polymer long chain is introduced, the mechanical strength of the polymer is increased, the composite proton exchange membrane prepared by the polymer long chain is used for effectively improving the mechanical property of the ultrathin proton exchange membrane, and simultaneously, the hydrophilic phase is used for improving the moisture retention property, and the group ionization on the molecular chain is used for improving the proton conductivity of the membrane, so that the conductivity of the proton membrane is ensured. In addition, the invention also has the following advantages:
(1) the introduced olefin prolongs the molecular chain of the polymer, the viscosity of the polymer rises along with the olefin, the mechanical property of the membrane is favorably improved, and the dispersing agent stannous pyrophosphate is added to solve the problem of uneven mixing caused by the rise of the viscosity, so that the performance of the prepared composite membrane is more stable, the process of proton jumping is more smooth, and the proton conductivity is favorably improved;
(2) the dispersant stannous pyrophosphate is used as a metal organic matter, so that the conductivity is good, and the use of the dispersant is also beneficial to improving the conductivity of the proton exchange membrane;
(3) the introduced olefin is ethylene glycol diacrylate-200, so that a catechol group is brought, and a hydroxyl group can participate in proton transmission by forming a hydrogen bond network, thereby further reducing the resistance of proton transmission and improving the proton conductivity of the membrane.
Drawings
FIG. 1 is a nuclear magnetic hydrogen spectrum of the hyperbranched polymer prepared in example 1 in deuterated DMSO.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The experimental procedures used in the following examples are conventional unless otherwise specified. The materials, reagents, methods and apparatus used, unless otherwise specified, are conventional in the art and are commercially available to those skilled in the art.
Example 1:
firstly, preparing a hyperbranched polymer adhesive:
(1) pentaerythritol tetraacrylate of 4 percent, ethylene glycol diacrylate of 5 percent-200, dopamine hydrochloride of 10 percent and dimethyl sulfoxide of 81 percent are taken and added into the round-bottom flask at the same time.
(2) The mixture was stirred until clear, and triethylamine was then added dropwise until the pH was adjusted to 8.
(3) Keeping the reaction in the dark, stirring for 3h at constant temperature of 60 ℃ in an oil bath, and carrying out polymerization reaction.
(4) After the polymerization is finished, obtaining a clear solution by suction filtration, adding a precipitator methyl tert-butyl ether into the solution until no new precipitate is generated, and then filtering to obtain a precipitate product.
(5) And (4) drying the precipitated product obtained in the step (4) at the vacuum chamber temperature for 24 hours.
(6) The dried product is the hyperbranched polymer adhesive with strong viscosity.
The nuclear magnetic hydrogen spectrum of the obtained hyperbranched polymer binder in deuterated DMSO is shown in figure 1, and as can be seen from figure 1, the double bond peak of vinyl disappears, and a proton peak is observed in the benzene ring of the catechol group at 6.3-6.62ppm, which indicates that the catechol group has been successfully introduced into the hyperbranched polymer and is completely added to the double bond of the vinyl.
Secondly, preparing the ultrathin reinforced composite proton exchange membrane:
(1) selecting perfluorosulfonic acid resin powder with equivalent weight of 1000, dissolving the perfluorosulfonic acid resin powder with mass fraction of 10% in N-methylpyrrolidone solvent, heating and stirring at 60 ℃ until the perfluorosulfonic acid resin powder is completely dissolved, and then removing bubbles in a vacuum oven to obtain a uniform solution.
(2) And (3) taking 0.5 percent of the hyperbranched polymer binder by mass fraction, dispersing in a dimethyl sulfoxide solvent, and stirring in an argon atmosphere until the hyperbranched polymer binder is dissolved to form a uniform solution.
(3) And (3) taking the solutions obtained in the steps (1) and (2) according to the mass fraction of the hyperbranched polymer solute in 1% of the total solute, adding 0.1% of dispersant stannous pyrophosphate into the obtained mixed solution, and mixing and stirring for 1h in a nitrogen atmosphere to obtain the membrane-making solution.
(4) And (4) preparing the membrane-making solution obtained in the step (3) into a membrane, and evaporating the solvent at 80 ℃ to form the ultrathin enhanced composite proton exchange membrane with the thickness of 10 microns.
Purifying and protonating ultrathin reinforced composite proton exchange membrane
Firstly, soaking the prepared ultrathin reinforced composite proton exchange membrane in a hydrogen peroxide solution with the mass fraction of 3% -5% at the temperature of 80 ℃ for 1h, and then washing out residual hydrogen peroxide by deionized water for multiple times; h at 0.5M2SO4Soaking in the solution for 1H, then soaking in deionized water for 0.5-2H (changing water for at least 3 times), and washing off residual H2SO4And (4) dissolving to obtain the purified and protonated proton exchange membrane.
Fourthly, performance test
Testing the purified and protonated ultrathin proton exchange membrane at room temperature to obtain the ultrathin proton exchange membrane with the tensile strength of 70MPa, the elongation at break of 225 percent and the linear swelling rate of 10 percent; the proton conductivity of the proton exchange membrane is 0.185S/cm when tested under the conditions of 80 ℃ and 100% humidity. The details are shown in tables 1-3.
Example 2
Firstly, preparing a hyperbranched polymer adhesive:
(1) taking 4.5 percent of pentaerythritol tetraacrylate, 6 percent of ethylene glycol diacrylate-200, 11 percent of dopamine hydrochloride and 78.5 percent of dimethyl sulfoxide by mass fraction, and simultaneously adding the materials into a round-bottom flask.
(2) The mixture was stirred until clear, and triethylamine was then added dropwise until the pH was adjusted to 8.
(3) Keeping the reaction in the dark, stirring for 4h at constant temperature of 70 ℃ in an oil bath, and carrying out polymerization reaction.
(4) After the polymerization is finished, obtaining a clear solution by suction filtration, adding a precipitator methyl tert-butyl ether into the solution until no new precipitate is generated, and then filtering to obtain a precipitate product.
(5) And (4) drying the precipitated product obtained in the step (4) at the vacuum chamber temperature for 24 hours.
(6) The dried product is the hyperbranched polymer adhesive with strong viscosity.
As for the nuclear magnetic hydrogen spectrum diagram of the obtained hyperbranched polymer binder in deuterated DMSO, the diagram shows that the double bond peak of vinyl disappears, and a proton peak is observed in the benzene ring of the catechol group, which indicates that the catechol group has been successfully introduced into the hyperbranched polymer and is completely added to the double bond of the vinyl.
Secondly, preparing the ultrathin reinforced composite proton exchange membrane:
(1) selecting perfluorosulfonic acid resin powder with equivalent weight of 1000, dissolving the perfluorosulfonic acid resin powder with mass fraction of 20% in N-methylpyrrolidone solvent, heating and stirring at 80 ℃ until the perfluorosulfonic acid resin powder is completely dissolved, and then removing bubbles in a vacuum oven to obtain a uniform solution.
(2) And (3) taking 5% of the hyperbranched polymer binder by mass percent, dispersing in a dimethyl sulfoxide solvent, and stirring in an argon atmosphere until the hyperbranched polymer binder is dissolved to form a uniform solution.
(3) And (3) taking the solutions obtained in the steps (1) and (2) according to the mass percent of the hyperbranched polymer solute accounting for 10% of the total solute, adding 0.5% of dispersant stannous pyrophosphate into the obtained mixed solution, and mixing and stirring for 2 hours in a nitrogen atmosphere to obtain the membrane-making solution.
(4) And (4) preparing the membrane-making solution obtained in the step (3) into a membrane, and evaporating the solvent at 80 ℃ to form the ultrathin enhanced composite proton exchange membrane with the thickness of 10 microns.
Purifying and protonating ultrathin reinforced composite proton exchange membrane
Firstly, soaking the prepared ultrathin reinforced composite proton exchange membrane in a hydrogen peroxide solution with the mass fraction of 3% -5% at the temperature of 80 ℃ for 1h, and then washing out residual hydrogen peroxide by deionized water for multiple times; h at 0.5M2SO4Soaking in the solution for 1H, then soaking in deionized water for 0.5-2H (changing water for at least 3 times), and washing off residual H2SO4And (4) dissolving to obtain the purified and protonated proton exchange membrane.
Fourthly, performance test
Testing the purified and protonated ultrathin proton exchange membrane at room temperature to obtain the ultrathin proton exchange membrane with the tensile strength of 76MPa, the elongation at break of 240 percent and the linear swelling rate of 7 percent; the conductivity of the proton exchange membrane is 0.232S/cm when the proton exchange membrane is tested under the conditions of 80 ℃ and 100% humidity. The details are shown in tables 1-3.
Example 3
Firstly, preparing a hyperbranched polymer adhesive:
(1) 5 percent of pentaerythritol tetraacrylate, 7 percent of ethylene glycol diacrylate-200, 12 percent of dopamine hydrochloride and 76 percent of dimethyl sulfoxide are taken and added into a round-bottom flask at the same time.
(2) The mixture was stirred until clear, and triethylamine was then added dropwise until the pH was adjusted to 8.
(3) Keeping the reaction in the dark, stirring for 2h at constant temperature of 80 ℃ in an oil bath, and carrying out polymerization reaction.
(4) After the polymerization is finished, obtaining a clear solution by suction filtration, adding a precipitator methyl tert-butyl ether into the solution until no new precipitate is generated, and then filtering to obtain a precipitate product.
(5) And (4) drying the precipitated product obtained in the step (4) at the vacuum chamber temperature for 24 hours.
(6) The dried product is the hyperbranched polymer adhesive with strong viscosity.
As for the nuclear magnetic hydrogen spectrum diagram of the obtained hyperbranched polymer binder in deuterated DMSO, the diagram shows that the double bond peak of vinyl disappears, and a proton peak is observed in the benzene ring of the catechol group, which indicates that the catechol group has been successfully introduced into the hyperbranched polymer and is completely added to the double bond of the vinyl.
Secondly, preparing the ultrathin reinforced composite proton exchange membrane:
(1) selecting perfluorosulfonic acid resin powder with equivalent weight of 1000, dissolving the perfluorosulfonic acid resin powder with mass fraction of 5% in N-methylpyrrolidone solvent, heating and stirring at 80 ℃ until the perfluorosulfonic acid resin powder is completely dissolved, and then removing bubbles in a vacuum oven to obtain a uniform solution.
(2) And (3) taking 10% of the hyperbranched polymer binder by mass fraction, dispersing in a dimethyl sulfoxide solvent, and stirring in an argon atmosphere until the hyperbranched polymer binder is dissolved to form a uniform solution.
(3) And (3) taking the solutions obtained in the steps (1) and (2) according to the mass fraction of the hyperbranched polymer solute in the total solute of 20%, adding 1% of dispersant stannous pyrophosphate into the obtained mixed solution, and mixing and stirring for 2 hours in a nitrogen atmosphere to obtain the membrane-making solution.
(4) And (4) preparing the membrane-making solution obtained in the step (3) into a membrane, and evaporating the solvent at 80 ℃ to form the ultrathin enhanced composite proton exchange membrane with the thickness of 10 microns.
Purifying and protonating ultrathin reinforced composite proton exchange membrane
Firstly, soaking the prepared ultrathin reinforced composite proton exchange membrane in a hydrogen peroxide solution with the mass fraction of 3% -5% at the temperature of 80 ℃ for 1h, and then washing out residual hydrogen peroxide by deionized water for multiple times; h at 0.5M2SO4Soaking in the solution for 1H, then soaking in deionized water for 0.5-2H (changing water for at least 3 times), and washing off residual H2SO4And (4) dissolving to obtain the purified and protonated proton exchange membrane.
Fourthly, performance test
Testing the purified and protonated ultrathin proton exchange membrane at room temperature to obtain the ultrathin proton exchange membrane with the tensile strength of 81MPa, the elongation at break of 248 percent and the linear swelling rate of 4.4 percent; the conductivity of the proton exchange membrane is 0.260S/cm when the proton exchange membrane is tested under the condition of 80 ℃ and the humidity of 100 percent. The details are shown in tables 1-3.
Example 4
Firstly, preparing a hyperbranched polymer adhesive:
(1) taking 4.5 percent of pentaerythritol tetraacrylate, 6 percent of ethylene glycol diacrylate-200, 11 percent of dopamine hydrochloride and 78.5 percent of dimethyl sulfoxide by mass fraction, and simultaneously adding the materials into a round-bottom flask.
(2) The mixture was stirred until clear, and triethylamine was then added dropwise until the pH was adjusted to 8.
(3) Keeping the reaction in the dark, stirring for 4h at constant temperature of 70 ℃ in an oil bath, and carrying out polymerization reaction.
(4) After the polymerization is finished, obtaining a clear solution by suction filtration, adding a precipitator methyl tert-butyl ether into the solution until no new precipitate is generated, and then filtering to obtain a precipitate product.
(5) And (4) drying the precipitated product obtained in the step (4) at the vacuum chamber temperature for 24 hours.
(6) The dried product is the hyperbranched polymer adhesive with strong viscosity.
As for the nuclear magnetic hydrogen spectrum diagram of the obtained hyperbranched polymer binder in deuterated DMSO, the diagram shows that the double bond peak of vinyl disappears, and a proton peak is observed in the benzene ring of the catechol group, which indicates that the catechol group has been successfully introduced into the hyperbranched polymer and is completely added to the double bond of the vinyl.
Secondly, preparing the ultrathin reinforced composite proton exchange membrane:
(1) selecting perfluorosulfonic acid resin powder with equivalent weight of 1000, dissolving the perfluorosulfonic acid resin powder with mass fraction of 20% in N-methylpyrrolidone solvent, heating and stirring at 80 ℃ until the perfluorosulfonic acid resin powder is completely dissolved, and then removing bubbles in a vacuum oven to obtain a uniform solution.
(2) And (3) taking 12% of the hyperbranched polymer binder by mass percent, dispersing in a dimethyl sulfoxide solvent, and stirring in an argon atmosphere until the hyperbranched polymer binder is dissolved to form a uniform solution.
(3) And (3) taking the solutions obtained in the steps (1) and (2) according to the mass percent of the hyperbranched polymer solute accounting for 10% of the total solute, adding 0.5% of dispersant stannous pyrophosphate into the obtained mixed solution, and mixing and stirring for 2 hours in a nitrogen atmosphere to obtain the membrane-making solution.
(4) And (4) preparing the membrane-making solution obtained in the step (3) into a membrane, and evaporating the solvent at 80 ℃ to form the ultrathin enhanced composite proton exchange membrane with the thickness of 10 microns.
Purifying and protonating ultrathin reinforced composite proton exchange membrane
Firstly, soaking the prepared ultrathin reinforced composite proton exchange membrane in a hydrogen peroxide solution with the mass fraction of 3% -5% at the temperature of 80 ℃ for 1h, and then washing out residual hydrogen peroxide by deionized water for multiple times; h at 0.5M2SO4Soaking in the solution for 1H, then soaking in deionized water for 0.5-2H (changing water for at least 3 times), and washing off residual H2SO4And (4) dissolving to obtain the purified and protonated proton exchange membrane.
Fourthly, performance test
Testing the purified and protonated ultrathin proton exchange membrane at room temperature to obtain the ultrathin proton exchange membrane with the tensile strength of 72MPa, the elongation at break of 260 percent and the linear swelling rate of 3.9 percent; the conductivity of the proton exchange membrane is 0.245S/cm when the proton exchange membrane is tested under the conditions of 80 ℃ and 100% humidity. The details are shown in tables 1-3.
Comparative example 1
Firstly, preparing an ultrathin enhanced composite proton exchange membrane:
(1) selecting perfluorosulfonic acid resin powder with equivalent weight of 1000, dissolving the perfluorosulfonic acid resin powder with mass fraction of 5% in N-methylpyrrolidone solvent, heating and stirring at 80 ℃ until the perfluorosulfonic acid resin powder is completely dissolved, and then removing bubbles in a vacuum oven to obtain a uniform solution.
(2) Preparing the membrane-forming solution obtained in the step (1) into a membrane, and evaporating the solvent at 80 ℃ to form the ultrathin enhanced composite proton exchange membrane with the thickness of 10 microns.
Purifying and protonating ultrathin reinforced composite proton exchange membrane
Firstly, soaking the prepared ultrathin reinforced composite proton exchange membrane in a hydrogen peroxide solution with the mass fraction of 3% -5% at the temperature of 80 ℃ for 1h, and then washing out residual hydrogen peroxide by deionized water for multiple times; h at 0.5M2SO4Soaking in the solution for 1H, then soaking in deionized water for 0.5-2H (changing water for at least 3 times), and washing off residual H2SO4And (4) dissolving to obtain the purified and protonated proton exchange membrane.
Third, performance test
Testing the purified and protonated ultrathin proton exchange membrane at room temperature to obtain the ultrathin proton exchange membrane with the tensile strength of 15MPa, the elongation at break of 140 percent and the linear swelling rate of 15 percent; the conductivity of the proton exchange membrane is 0.140S/cm when tested under the conditions of 80 ℃ and 100% humidity. The details are shown in tables 1-3.
Comparative example 2
Firstly, preparing an ultrathin enhanced composite proton exchange membrane:
(1) selecting perfluorosulfonic acid resin powder with equivalent weight of 1000, dissolving the perfluorosulfonic acid resin powder with mass fraction of 5% in N-methylpyrrolidone solvent, heating and stirring at 80 ℃ until the perfluorosulfonic acid resin powder is completely dissolved, and then removing bubbles in a vacuum oven to obtain a uniform solution.
(2) And (2) adding 0.1% of dispersant stannous pyrophosphate into the solution obtained in the step (1), and mixing and stirring for 2 hours in a nitrogen atmosphere to obtain a membrane-making solution.
(3) Preparing the membrane-forming solution obtained in the step (2) into a membrane, and evaporating the solvent at 80 ℃ to form the ultrathin enhanced composite proton exchange membrane with the thickness of 10 microns.
Second, purify the ultrathin enhancement mode compound proton exchange membrane
Firstly, soaking the prepared ultrathin reinforced composite proton exchange membrane in a hydrogen peroxide solution with the mass fraction of 3% -5% at the temperature of 80 ℃ for 1h, and then washing out residual hydrogen peroxide by deionized water for multiple times; h at 0.5M2SO4Soaking in the solution for 1h, and then soaking in the solutionSoaking in deionized water for 0.5-2H (at least changing water for 3 times), and washing off residual H2SO4And (4) dissolving to obtain the purified and protonated proton exchange membrane.
Third, performance test
Testing the purified and protonated ultrathin proton exchange membrane at room temperature to obtain the ultrathin proton exchange membrane with the tensile strength of 15MPa, the elongation at break of 140 percent and the linear swelling rate of 15 percent; the conductivity of the proton exchange membrane is 0.142S/cm when tested under the conditions of 80 ℃ and 100% humidity. The details are shown in tables 1-3.
Comparative example 3
Firstly, preparing a hyperbranched polymer adhesive:
(1) 5 percent of pentaerythritol tetraacrylate, 7 percent of ethylene glycol diacrylate-200, 12 percent of dopamine hydrochloride and 76 percent of dimethyl sulfoxide are taken and added into a round-bottom flask at the same time.
(2) The mixture was stirred until clear, and triethylamine was then added dropwise until the pH was adjusted to 8.
(3) Keeping the reaction in the dark, stirring for 2h at constant temperature of 80 ℃ in an oil bath, and carrying out polymerization reaction.
(4) After the polymerization is finished, obtaining a clear solution by suction filtration, adding a precipitator methyl tert-butyl ether into the solution until no new precipitate is generated, and then filtering to obtain a precipitate product.
(5) And (4) drying the precipitated product obtained in the step (4) at the vacuum chamber temperature for 24 hours.
(6) The dried product is the hyperbranched polymer adhesive with strong viscosity.
As for the nuclear magnetic hydrogen spectrum diagram of the obtained hyperbranched polymer binder in deuterated DMSO, the diagram shows that the double bond peak of vinyl disappears, and a proton peak is observed in the benzene ring of the catechol group, which indicates that the catechol group has been successfully introduced into the hyperbranched polymer and is completely added to the double bond of the vinyl.
Secondly, preparing the ultrathin reinforced composite proton exchange membrane:
(1) selecting perfluorosulfonic acid resin powder with equivalent weight of 1000, dissolving the perfluorosulfonic acid resin powder with mass fraction of 5% in N-methylpyrrolidone solvent, heating and stirring at 80 ℃ until the perfluorosulfonic acid resin powder is completely dissolved, and then removing bubbles in a vacuum oven to obtain a uniform solution.
(2) And (3) taking 10% of the hyperbranched polymer binder by mass fraction, dispersing in a dimethyl sulfoxide solvent, and stirring in an argon atmosphere until the hyperbranched polymer binder is dissolved to form a uniform solution.
(3) And (3) taking the solutions obtained in the steps (1) and (2) according to the mass fraction of the hyperbranched polymer solute in the total solute of 20%, adding stannous pyrophosphate serving as a dispersing agent into the obtained mixed solution, and mixing and stirring for 2 hours in a nitrogen atmosphere to obtain a membrane making solution.
(4) And (4) preparing the membrane-making solution obtained in the step (3) into a membrane, and evaporating the solvent at 80 ℃ to form the ultrathin enhanced composite proton exchange membrane with the thickness of 10 microns.
Purifying and protonating ultrathin reinforced composite proton exchange membrane
Firstly, soaking the prepared ultrathin reinforced composite proton exchange membrane in a hydrogen peroxide solution with the mass fraction of 3% -5% at the temperature of 80 ℃ for 1h, and then washing out residual hydrogen peroxide by deionized water for multiple times; h at 0.5M2SO4Soaking in the solution for 1H, then soaking in deionized water for 0.5-2H (changing water for at least 3 times), and washing off residual H2SO4And (4) dissolving to obtain the purified and protonated proton exchange membrane.
Fourthly, performance test
Testing the purified and protonated ultrathin proton exchange membrane at room temperature to obtain the ultrathin proton exchange membrane with the tensile strength of 61MPa, the elongation at break of 210 percent and the linear swelling rate of 5.6 percent; the conductivity of the proton exchange membrane is 0.170S/cm when tested under the conditions of 80 ℃ and 100% humidity. The details are shown in tables 1-3.
The proton conductivity testing method comprises the steps of placing a diaphragm in a self-made proton conductivity clamp, testing the resistance of the diaphragm in the in-plane direction by adopting a four-electrode method, and finally calculating according to a conductivity formula to obtain the proton conductivity testing device. Tensile properties and linear swell ratio are tested by reference to GB/T20042.3-2009, where test specimens are 2 x 4cm strips and the machine direction tensile strength is measured. The results are shown in tables 1 to 3:
TABLE 1 proton conductivity of different proton exchange membranes
Kind of diaphragm
Thickness (μm)
Temperature (. degree.C.)
Conductivity (S/cm)
Dupont 211 film
25
80
0.100
Example 1
10
80
0.185
Example 2
10
80
0.232
Example 3
10
80
0.260
Example 4
10
80
0.245
Comparative example 1
10
80
0.140
Comparative example 2
10
80
0.142
Comparative example 3
10
80
0.170
TABLE 2 mechanical Properties of different proton exchange membranes
Kind of diaphragm
Test temperature
Mechanical Strength (MPa)
Elongation at Break (%)
Thickness (μm)
Dupont 211 film
At room temperature
22
180
25
Example 1
At room temperature
70
225
10
Example 2
At room temperature
76
240
10
Example 3
At room temperature
81
248
10
Example 4
At room temperature
72
260
10
Comparative example 1
At room temperature
15
140
10
Comparative example 2
At room temperature
15
140
10
Comparative example 3
At room temperature
61
210
10
TABLE 3 Linear swelling Rate of different proton exchange membranes