CN104371128B - High-strength mechanical performance alkaline negative ion exchange composite film, preparation and application - Google Patents

Abstract

The present invention relates to the preparation and application of a basic anion exchange composite membrane with high strength mechanical properties, and its components include: low molecular weight oxygen-containing water-soluble polyvinyl alcohol and water-soluble chlorinated-1-ethylene containing quaternary ammonium groups A polymer of 3-methyl-1H-imidazole and 1-vinyl-2-pyrrolidone. Its preparation method is as follows: oxygen-containing water-soluble PVA and quaternary ammonium group-containing Dissolve in deionized water respectively to obtain a uniform mixed solution; then vacuum filter, pour the filtered solution into a plastic petri dish, and obtain a polymer film after natural drying; the polymer film is thermally and physically cross-linked, and then chemically cross-linked , and finally immersed in KOH solution for ion exchange. The preparation method of the invention not only has easy-to-obtain raw materials, low cost and no pollution, but also has mild reaction conditions and short reaction time, has the advantages of simple process, practicality, strong controllability, etc., and is easy for large-scale production.

Description

Basic anion exchange composite membrane with high strength mechanical properties, preparation and application

technical field

The invention belongs to the field of alkaline membrane and its preparation and application, in particular to an alkaline anion-exchange composite membrane with high-strength mechanical properties and its preparation and application.

Background technique

Polymer membrane fuel cells (PEMFC), according to the different conductive ions, can be divided into proton exchange membrane (PEM) fuel cells and alkaline anion exchange membrane (AEM) fuel cells. PEM fuel cells have the advantages of low pollution emission, low operating temperature, short activation time, long life, stable operation, easy mass production, high energy conversion efficiency, etc., and have become one of the important energy technologies with high efficiency and environmental friendliness in the 21st century [MAJCropper , S. Geiger, DM Jollie, J. Power Sources 131 (2004) 57-61; JR Varcoe, RCTSlade, E. Lam How Yee, SD Poynton, DJ Driscoll, DC Apperley, Chem. Mater. 19 (2007) 2686-2693.]. For example, the proton exchange membrane produced by DuPont Company of the United States It has excellent electrical conductivity and chemical, electrochemical and mechanical stability and is widely used. However, The membrane production process is complex, expensive and unstable at high temperature, which limits its commercial development [V.Neburchilov, J.Martin, H.Wang, J.Zhang, A review of polymerelectrolytemembranes for direct methanol fuel cells, Journal of Power Sources 169 (2007) 221].

In recent years, AEMs and their applications in fuel cells have attracted extensive attention. AEM fuel cells have faster reaction kinetics, and the risks of fuel leakage and CO poisoning are also greatly suppressed. In addition, non-platinum noble metals can be used as catalysts, which can effectively reduce the cost of fuel cells. There are many types of alkaline anion exchange composite membranes (AEM), and their skeletons range from polyolefin (PO), polysiloxane (PSO), biphenyl polyether ketone (PPEK), polyarylene ether sulfone (PAES) to organic/ Inorganic composite materials [YJWang, JLQiao, R.Baker, JJZhang, Chem.Soc.Rev.42(2013)5768; JFZhou, M. I. Anestis-Richard, PA Kohl, J. Membr. Sci. 350 (2010) 286-292; MA Abdel Rahim, R R Abdel Hameed, MW Khalil, J. Power Sources 134 (2004) 160; SMA Shibili, M. Noel, J. Power Sources 45 (1993) 139; S. Lu, J. Pan, A. Huang, L. Zhuang, J. Lu, Proc. Natl. Acad. Sci. USA 105 (2008) 20611-20614; J. Wang, J. Wang , S. Li, S. Zhang, J. Membr. Sci. 368 (2011) 246-253]. However, the preparation process of these anion exchange membranes is complicated, and at the same time, they are unstable under high-concentration lye, especially at higher temperatures (greater than 60°C), resulting in a decline in membrane performance or even membrane degradation, and a sharp decline in the mechanical strength of the membrane. Therefore, , it is of great significance to research and develop new basic anion exchange membranes with high performance, high stability, superior mechanical strength, easy preparation and low price.

Contents of the invention

The technical problem to be solved by the present invention is to provide a basic anion exchange composite membrane with high strength mechanical properties and its preparation and application. The membrane exhibits high tensile performance and has a certain elongation at break , significantly reducing the cost of the fuel cell, the preparation method is simple, the cost is low, the film-forming property is good, and it is suitable for industrial production.

In order to solve the above-mentioned technical problems, the present invention provides a high-strength mechanical performance basic anion-exchange composite membrane, which is characterized in that it includes low molecular weight oxygen-containing water-soluble polyvinyl alcohol (PVA) and water-soluble polyvinyl alcohol (PVA) containing quaternary ammonium groups. thing ( series of polymers).

Preferably, the weight-average molecular weight of the low-molecular-weight oxygen-containing water-soluble vinyl alcohol is 89000< _Mw <98000; the water-soluble polymer containing quaternary ammonium groups is chlorinated-1-vinyl-3-methyl - Polymer of 1H-imidazole and 1-vinyl-2-pyrrolidone.

The present invention also provides a method for preparing the above-mentioned high-strength mechanical performance alkaline anion-exchange composite membrane, which is characterized in that it comprises the following steps:

Step 1): The polymers of oxygen-containing water-soluble polyvinyl alcohol and chloride-1-vinyl-3-methyl-1H-imidazole and 1-vinyl-2-pyrrolidone are respectively configured into aqueous solutions, and the chlorine Slowly add the polymer aqueous solution of 1-vinyl-3-methyl-1H-imidazole and 1-vinyl-2-pyrrolidone into the stirred oxygen-containing water-soluble polyvinyl alcohol aqueous solution, and continue stirring until a uniform mixture is formed The solution was vacuum filtered, the filtrate was poured into a plastic petri dish, and dried naturally to form a film to obtain a polymer film;

Step 2): The polymer film obtained in step 1) is naturally peeled off from the petri dish, physically cross-linked by heat treatment, then chemically cross-linked, and finally immersed in KOH solution for ion exchange.

Preferably, the heat treatment physical crosslinking temperature in the step 2) is 130-190°C; the crosslinking time is 30min-2h.

Further, the heat treatment physical crosslinking temperature in the step 2) is 170° C.; the crosslinking time is 1 h.

Preferably, the chemical crosslinking time in step 2) is 1 h.

Preferably, the molar concentration of the KOH solution in step 2) is 1-6 mol/L.

The invention also provides an alkaline anion exchange composite membrane with high strength and mechanical properties, which is applied to the preparation of membrane electrodes of alkaline fuel cells.

Preferably, the alkaline fuel cell membrane electrode is a metal-air battery, _CO2 electrochemical reduction, and chlor-alkali industrial diaphragm material.

Compared with prior art, the beneficial effect of the present invention is:

(1) The basic anion exchange composite membrane of the present invention not only exhibits excellent tensile properties, but the tensile strength can reach 76.7Mpa under the condition of physical crosslinking temperature of 130°C; Under the condition of temperature 170℃, the elongation at break is 14.9%, which has excellent mechanical stability;

(2) The preparation method of the present invention is simple, low in cost, easy to operate, good in film-forming property, and suitable for industrialized production;

(3) Alkaline anion exchange composite membrane of the present invention can be used directly with H2-air fuel cell, also can be used as metal-air battery and CO _The membrane material of electrochemical reduction, significantly reduces the manufacturing cost of fuel cell.

Description of drawings

Figure 1 shows the stress-strain curves of the PVA/Luviquat FC370 basic anion exchange composite membrane after physical crosslinking for 1 hour at 130°C, 150°C, 170°C and 190°C, and then chemical crosslinking for 1 hour;

Figure 2 is a comparison of appearance photos of PVA/Luviquat FC370 alkaline anion exchange membrane before and after physical crosslinking at 170°C;

Figure 3 shows the oxidation stability of PVA/Luviquat FC370 alkaline anion exchange membrane after physical crosslinking at 170°C for 1 hour and chemical crosslinking for 1 hour;

Figure 4 shows the electrical conductivity and water content of the PVA/Luviquat FC370 alkaline anion exchange membrane after physical crosslinking at 130°C, 150°C, 170°C and 190°C for 1 hour, and chemical crosslinking for 1 hour after ion exchange with 2M KOH solution;

Figure 5 shows the PVA/Luviquat FC370 basic anion exchange membranes were immersed in 2 M Comparison of appearance photos in KOH solution;

Fig. 6 is the single-cell power generation curve of the PVA/Luviquat FC370 alkaline anion exchange membrane at 130°C for 1 hour of physical cross-linking and 1 hour of chemical cross-linking to prepare a membrane electrode (MEA) at normal temperature and pressure.

detailed description

In order to make the present invention more comprehensible, preferred embodiments are described in detail below with accompanying drawings.

The oxygen-containing water-soluble PVA in Examples 1-6 is produced by Sigma-Aldrich (Shanghai) Trading Co., Ltd.; Luviquat uses FC370 produced by Sigma-Aldrich (Shanghai) Trading Co., Ltd.

Example 1

30g of oxygen-containing water-soluble PVA powder (molecular weight: 89000-98000) was dissolved in 300ml of deionized water, heated and stirred at 90°C until a transparent and homogeneous solution was prepared to obtain a 10% PVA stock solution. Press PVA with FC370 mass ratio = 1: 1 the above PVA aqueous solution and Mix FC370 (molecular weight: about 400,000) solutions, stir to form a uniform transparent solution, pour the mixed solution into a plastic disc, and dry it naturally to form a film. The membrane was naturally peeled off, and after being physically cross-linked in an oven at 130°C for 1 h, the membrane was then immersed in 15 mL of 10% glutaraldehyde (GA, 25 wt%) acetone (≥99.5 wt%) solution containing a small amount of HCl, at room temperature After the chemical cross-linking reaction was carried out for 1 h, the membrane was taken out and fully washed by immersing in deionized water. The PVA/ The FC370 membrane was soaked in 2M KOH solution for ion exchange for 24 hours and then taken out, and the KOH adsorbed on the surface of the membrane was repeatedly washed with deionized water to neutrality to obtain PVA/ FC370 basic anion exchange composite membrane.

The test is carried out by H5K-S material testing machine (Hounsfield, UK) in a constant temperature and humidity environment at 20° C. and 60% relative humidity. The test speed is 5mm/min, and the sample standard is 2cm×1cm. The results are shown in Figure 1. It can be seen from the figure that the film has strong tensile properties, with a maximum tensile strength of 76.7MPa, an elongation at break of 11.8%, and a Young's modulus of 958.5MPa. Under the condition of the same elongation at break of 8%, the basic anion exchange membrane treated with physical crosslinking temperature of 130℃ has the maximum tensile strength of 67.2MPa.

Example 2

30 g of PVA powder (molecular weight: 89000-98000) was dissolved in 300 ml of deionized water, heated and stirred at 90° C. until a transparent and homogeneous solution was prepared to obtain a 10% PVA stock solution. Press PVA with FC370 mass ratio = 1: 1 the above PVA aqueous solution and Mix FC370 (molecular weight: about 400,000) solutions, stir to form a uniform transparent solution, pour the mixed solution into a plastic disc, and dry it naturally to form a film. The membrane was naturally peeled off, and after being physically cross-linked in an oven at 150°C for 1 h, the membrane was then immersed in 15 mL of 10% glutaraldehyde (GA, 25 wt%) acetone (≥99.5 wt%) solution containing a small amount of HCl, at room temperature After the chemical cross-linking reaction was carried out for 1 h, the membrane was taken out and fully washed by immersing in deionized water. The PVA/ The FC370 membrane was soaked in 2M KOH solution for ion exchange for 24 hours and then taken out, and the KOH adsorbed on the surface of the membrane was repeatedly washed with deionized water to neutrality to obtain PVA/ FC370 basic anion exchange composite membrane.

The test is carried out by H5K-S material testing machine (Hounsfield, UK) in a constant temperature and humidity environment at 20° C. and 60% relative humidity. The test speed is 5mm/min, and the sample standard is 2cm×1cm. The results are shown in Figure 1. The film also has strong tensile properties, with a tensile strength of 62.6 MPa, an elongation at break of 14.1%, and a Young's modulus of 791.7 MPa.

Example 3

30 g of PVA powder (molecular weight: 89000-98000) was dissolved in 300 ml of deionized water, heated and stirred at 90° C. until a transparent and homogeneous solution was prepared to obtain a 10% PVA stock solution. Press PVA with FC370 mass ratio = 1: 1 the above PVA aqueous solution and Mix FC370 (molecular weight: about 400,000) solutions, stir to form a uniform transparent solution, pour the mixed solution into a plastic disc, and dry it naturally to form a film. After the film was peeled off and placed in an oven at 170°C for physical crosslinking for 1 h, the film was then immersed in 15 mL of 10% glutaraldehyde (GA, 25 wt%) acetone (≥99.5 wt%) solution containing a small amount of HCl, at room temperature After the chemical cross-linking reaction was carried out for 1 h, the membrane was taken out, soaked in deionized water and washed thoroughly. The PVA/ The FC370 membrane was soaked in 2M KOH solution for ion exchange for 24 hours and then taken out, and the KOH adsorbed on the surface of the membrane was repeatedly washed with deionized water to neutrality to obtain PVA/ FC370 basic anion exchange composite membrane. Figure 2 is a comparison of the appearance photos of the PVA/Luviquat basic anion exchange membrane before and after physical crosslinking at 170°C. It can be seen from Figure 2 that the PVA/Luviquat basic anion exchange membrane changes from colorless to yellow before and after physical crosslinking at 170°C.

The test is carried out by H5K-S material testing machine (Hounsfield, UK) in a constant temperature and humidity environment at 20° C. and 60% relative humidity. The test speed is 5mm/min, and the sample standard is 2cm×1cm. The results are shown in Figure 1, the tensile strength was 59.3MPa, the elongation at break was 14.9%, and the Young's modulus was 793.0MPa. It can be seen from the figure that the membrane has the largest elongation at break. Under the same tensile strength of 50 MPa, the alkaline anion exchange membrane treated with physical crosslinking temperature at 170°C has the highest elongation at break, which can reach 10.6%.

Example 4

30 g of PVA powder (molecular weight: 89000-98000) was dissolved in 300 ml of deionized water, heated and stirred at 90° C. until a transparent and homogeneous solution was prepared to obtain a 10% PVA stock solution. Press PVA with FC370 mass ratio = 1: 1 the above PVA aqueous solution and Mix FC370 (molecular weight: about 400,000) solutions, stir to form a uniform transparent solution, pour the mixed solution into a plastic disc, and dry it naturally to form a film. The membrane was naturally peeled off, and after being physically cross-linked in an oven at 190°C for 1 h, the membrane was then immersed in 15 mL of 10% glutaraldehyde (GA, 25 wt%) acetone (≥99.5 wt%) solution containing a small amount of HCl, at room temperature After the chemical cross-linking reaction was carried out for 1 h, the membrane was taken out and fully washed by immersing in deionized water. The PVA/ The FC370 membrane was soaked in 2M KOH solution for ion exchange for 24 hours and then taken out, and the KOH adsorbed on the surface of the membrane was repeatedly washed with deionized water to neutrality to obtain PVA/ FC370 basic anion exchange composite membrane.

The test is carried out by H5K-S material testing machine (Hounsfield, UK) in a constant temperature and humidity environment at 20° C. and 60% relative humidity. The test speed is 5mm/min, and the sample standard is 2cm×1cm. The results are shown in Figure 1, the tensile strength is 59.9MPa, the elongation at break is 9.2%, and the Young's modulus is 800.4MPa, the results are all within the error range.

Example 5

30 g of PVA powder (molecular weight: 89000-98000) was dissolved in 300 ml of deionized water, heated and stirred at 90° C. until a transparent and homogeneous solution was prepared to obtain a 10% PVA stock solution. Press PVA with FC370 mass ratio = 1: 1 the above PVA aqueous solution and Mix FC370 (molecular weight: about 400,000) solutions, stir to form a uniform transparent solution, pour the mixed solution into a plastic disc, and dry it naturally to form a film. The membrane was naturally peeled off, and after being physically cross-linked in an oven at 170°C for 1 h, the membrane was then immersed in 15 mL of 10% glutaraldehyde (GA, 25 wt%) acetone (≥99.5 wt%) solution containing a small amount of HCl, at room temperature After the chemical cross-linking reaction was carried out for 1 h, the membrane was taken out, immersed in deionized water and fully washed to obtain a modified quaternary ammonium salt anion composite membrane. The PVA/ The FC370 membrane was soaked in 2M KOH solution for ion exchange for 24 hours and then taken out, and the KOH adsorbed on the surface of the membrane was repeatedly washed with deionized water to neutrality to obtain PVA/ FC370 basic anion exchange composite membrane, the membrane is stored in deionized water.

The PVA/Luviquat membranes prepared by the above method were immersed in H ₂ O ₂ (30wt%) solution at room temperature, and their mass changes were measured at regular intervals. The results are shown in Figure 3. The film exhibited excellent oxidation stability, and there was an obvious mass loss of 5% within 96h of immersion in H ₂ O ₂ (30wt%), but in the following 240, it was almost stable at the original mass. 93-94% of.

Example 6

30 g of PVA powder (molecular weight: 89000-98000) was dissolved in 300 ml of deionized water, heated and stirred at 90° C. until a transparent and homogeneous solution was prepared to obtain a 10% PVA stock solution. Press PVA with FC370 mass ratio = 1: 1 the above PVA aqueous solution and Mix FC370 (molecular weight: about 400,000) solutions, stir to form a uniform transparent solution, pour the mixed solution into a plastic disc, and dry it naturally to form a film. The membrane was peeled off naturally, placed in an oven at different temperatures (130°C, 150°C, 170°C, and 190°C) for physical crosslinking for 1 h, and then immersed in 15 mL of 10% glutaraldehyde (GA, 25wt%) acetone (≥99.5wt%) solution, carry out the chemical cross-linking reaction at room temperature for 1 hour, then take out the membrane, soak it in deionized water and wash it thoroughly. The PVA/ The FC370 membrane was soaked in 2M KOH solution for ion exchange for 24 hours and then taken out, and the KOH adsorbed on the surface of the membrane was repeatedly washed with deionized water to neutrality to obtain PVA/ FC370 basic anion exchange composite membrane, and then store the membrane in deionized water.

The electrical conductivity and water content were measured by AC impedance method and dry-wet weight method respectively. As shown in Figure 4, the electrical conductivity can reach 5.1×10 ^-3 Se em ^-1 and the water content is about 55%. Figure 5 shows the appearance of PVA/Luviquat basic anion exchange membrane immersed in 2M KOH solution after physical crosslinking for 1 hour at (a) 130°C (b) 150°C (c) 170°C (d) 190°C for 1 hour From the photo comparison chart, it can be seen from Figure 5 that the higher the temperature, the darker the color of the film.

Example 7

30 g of PVA powder (molecular weight: 89000-98000) was dissolved in 300 ml of deionized water, heated and stirred at 90° C. until a transparent and homogeneous solution was prepared to obtain a 10% PVA stock solution. Press PVA with FC370 mass ratio = 1: 1 (mentioned PVA aqueous solution and Mix FC370 (molecular weight: about 400,000) solutions, stir to form a uniform transparent solution, pour the mixed solution into a plastic disc, and dry it naturally to form a film. The film was peeled off and placed in an oven at 130°C for physical crosslinking for 1 h, and then immersed in 15 mL of 10% glutaraldehyde (GA, 25 wt%) acetone (≥99.5 wt%) solution containing a small amount of HCl, at room temperature After carrying out the chemical cross-linking reaction for 1 hour, the membrane was taken out, immersed in deionized water and fully washed to obtain a modified quaternary ammonium salt anion composite membrane. The PVA/ The FC370 membrane was soaked in 2M KOH solution for ion exchange for 24 hours and then taken out, and the KOH adsorbed on the surface of the membrane was repeatedly washed with deionized water to neutrality to obtain PVA/ FC370 basic anion exchange composite membrane.

Figure 6 for PVA/ Room temperature power generation curves of MEAH ₂ /O ₂ fuel cells with FC370 alkaline anion exchange membranes physically crosslinked at 130°C for 1 hour and chemically crosslinked for 1 hour. The cathode and anode both use 40% Pt/C catalyst from Johnson Matthey Company in the United States. It is 0.5mg/cm ² , and the effective area is 4cm ² . Under normal temperature and pressure, the hydrogen flow rate is 100mL/min, the oxygen flow rate is 70mL/min, and the single cell performance test is carried out. As can be seen from Figure 6, by PVA/ The open circuit voltage (OCV) of the MEA prepared by FC370 alkaline anion exchange membrane reaches 1.04V, which is equivalent to the commercial alkaline membrane of Tokuyama Company in Japan. The initial power generation is 11.40mW/cm ² and the maximum current density is 50.8mA/cm ² . It shows application potential in the field of alkaline fuel cells.

Claims (8)

1. A basic anion-exchange composite membrane with high-strength mechanical properties is characterized in that it comprises low-molecular-weight oxygen-containing water-soluble polyvinyl alcohol and a water-soluble polymer containing quaternary ammonium groups; said low-molecular-weight oxygen-containing water-soluble The weight-average molecular weight of vinyl alcohol is 89000< _Mw <98000; the water-soluble polymer containing quaternary ammonium group is chloro-1-vinyl-3-methyl-1H-imidazole and 1-vinyl-2-pyrrolidone of polymers. 2. a preparation method of the high-strength mechanical properties basic anion-exchange composite membrane claimed in claim 1, is characterized in that, comprises the following steps: Step 1): Prepare oxygen-containing water-soluble polyvinyl alcohol and polymers of chlorinated-1-vinyl-3-methyl-1H-imidazole and 1-vinyl-2-pyrrolidone into aqueous solutions, and chlorine Slowly add the polymer aqueous solution of 1-vinyl-3-methyl-1H-imidazole and 1-vinyl-2-pyrrolidone into the stirred oxygen-containing water-soluble polyvinyl alcohol aqueous solution, and continue stirring until a uniform mixture is formed The solution was vacuum filtered, the filtrate was poured into a plastic petri dish, and dried naturally to form a film to obtain a polymer film; Step 2): The polymer film prepared in step 1) is naturally peeled off from the petri dish, physically cross-linked by heat treatment, then chemically cross-linked, and finally immersed in KOH solution for ion exchange. 3. The method for preparing a high-strength mechanical property basic anion-exchange composite membrane as claimed in claim 2, characterized in that, the cross-linking temperature of heat treatment physical cross-linking in the step 2) is 130-190°C; cross-linking The time is 30min ~ 2h. 4. The preparation method of high-strength mechanical properties basic anion exchange composite membrane as claimed in claim 3, characterized in that, the cross-linking temperature of heat treatment physical cross-linking in the step 2) is 170°C; the cross-linking time is 1h. 5. The method for preparing a high-strength mechanical performance basic anion-exchange composite membrane according to any one of claims 2-4, characterized in that the time for chemical crosslinking in the step 2) is 1 hour. 6 . The method for preparing a basic anion exchange composite membrane with high strength and mechanical properties according to claim 2 , wherein the molar concentration of the KOH solution in step 2) is 1-6 mol/L. 7. A basic anion-exchange composite membrane with high strength mechanical properties as claimed in claim 1 is applied to the preparation of membrane electrodes for alkaline fuel cells. 8. the application of high-strength mechanical performance alkaline anion exchange composite membrane as claimed in claim 7, is characterized in that, described alkaline fuel cell membrane electrode is metal-air battery, _CO Electrochemical reduction and chlor-alkali industry diaphragm material .