CN114288873A - Polybenzimidazole microporous membrane with high acid resistance and high stability and preparation method thereof - Google Patents
Polybenzimidazole microporous membrane with high acid resistance and high stability and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a polybenzimidazole microporous membrane with high acid resistance and high stability, which comprises a hollow fiber membrane or a flat membrane, wherein the polybenzimidazole microporous membrane has the tensile strength of 30-60Mpa, the porosity of 65-85 percent, the average pore diameter of 0.10-0.25 mu m and the hydrophobic contact angle of 145 DEG; the tensile strength of the product is 28-57Mpa after the product is soaked in 1mol/L nitric acid solution, the hydrophobic contact angle can still be kept above 130 degrees, and the hydrophobic contact angle can still be kept above 130 degrees after the product is soaked in 5 pH sodium hypochlorite solution. The invention regulates and controls the film forming condition of the polybenzimidazole/hydrophobic polymer blending system by adjusting a gas phase induced phase separation method, and regulates and controls the surface microstructure of the film, so that the surface of the hydrophilic material has a rough micro-surface structure to achieve a lasting high hydrophobic effect.
Description
Technical Field
The invention belongs to the field of membrane distillation, and particularly relates to a polybenzimidazole microporous membrane with high acid resistance and high stability and a preparation method thereof.
Background
The key point of the high acidity heavy metal wastewater treatment technology is to keep the concentration of heavy metals in discharged water as low as possible and to keep the volume of heavy metal concentrated solution as small as possible. As a novel membrane technology combining traditional evaporation and membrane technology, the membrane distillation technology has the obvious advantages in the aspect of high-acidity heavy metal wastewater treatment compared with the traditional evaporation: firstly, a membrane distillation device generally operates at 30-70 ℃, and the energy consumption and the requirement on the safety of the device are obviously lower than those of the traditional evaporation; secondly, the membrane has an interception effect on most radioactive heavy metals in the high-radioactivity solution, so that a good interception effect is shown, and the concentration efficiency is high; compared with the traditional evaporation, the membrane distillation device is simple and convenient, occupies small area, can utilize low-grade heat sources (solar energy, terrestrial heat, waste heat and the like), and has high economical efficiency. Therefore, the membrane distillation technology can be used for the concentration treatment of the high-acidity heavy metal solution.
As a core material, the structure-property relation of a hydrophobic membrane used for membrane distillation determines the separation effect of the membrane distillation. The most commonly used membrane materials in the present membrane distillation process are polyvinylidene fluoride (PVDF), Polytetrafluoroethylene (PTFE) and polypropylene (PP), Polyethylene (PE), polyvinyl chloride (PVC), Polystyrene (PS). The PVDF and PTFE membranes have better performance, but the stability and the service life of the membranes are poorer in the process of treating high-acidity heavy metal wastewater, and the main reason is that the service life of a hydrophobic membrane used for membrane distillation is seriously limited by the highly corrosive service conditions.
Polybenzimidazole (OPBI) is a linear heterocyclic polymer containing benzimidazole groups, and has excellent thermal stability, mechanical strength and chemical resistance. At present, OPBI is mainly applied to the fields of proton exchange membranes of fuel cells and the like and is mainly prepared by a solution casting method, and a prepared PBI membrane is a non-porous membrane; in addition, the microporous membrane can be prepared by a non-solvent induced phase separation method, but the prepared microporous membrane has low porosity and low mechanical tensile strength, and the contact angle of an OPBI (oriented phase bonding) original membrane is 85-95 degrees (as shown in figure 1), so that the requirement of membrane distillation operation for high-acidity heavy metal wastewater on a high-hydrophobicity separation membrane is difficult to meet.
At present, few reports are reported on the hydrophobic modification of a polybenzimidazole protomembrane, researchers in the prior art mainly improve the hydrophobicity of the polybenzimidazole protomembrane by a chemical grafting method, a blending modification method and a surface spraying modification method, but the chemical grafting method can improve the hydrophobicity of the membrane and influence the mechanical property of the membrane, the hydrophobicity of the membrane after the blending modification can not meet the requirement of membrane distillation application, and the surface spraying modification can obviously improve the hydrophobicity of the membrane, but the service life of the polybenzimidazole membrane can be short by the method. In addition, the above modification method cannot ensure stability, and tends to improve membrane hydrophobicity, but has poor stability.
The present invention has been made to solve the above problems.
Disclosure of Invention
The preparation research of the open membrane distillation membrane material with OPBI as a main material is carried out for the first time, and the polybenzimidazole hydrophobic microporous membrane is successfully prepared by a simple and efficient method. The specific method idea is as follows: the method comprises the following specific operation steps of regulating and controlling the film forming conditions of a polybenzimidazole/hydrophobic polymer blending system by regulating a gas-phase induced phase separation method, and regulating and controlling the surface microstructure of a film, so that the surface of a hydrophilic material has a rough micro-surface structure to achieve a lasting high-hydrophobicity effect:
the invention provides a preparation method of a polybenzimidazole microporous membrane with high acid resistance and high stability, which comprises the following steps:
(1) mixing polybenzimidazole OPBI with a first solvent to prepare a membrane casting solution A;
(2) dissolving polydimethylsiloxane PDMS and tetraethoxysilane TEOS into a second solvent of tetrahydrofuran THF to form a membrane casting solution B;
(3) mixing and stirring the membrane casting solution A and the membrane casting solution B according to a certain proportion, and then adding a catalyst for mixing uniformly;
(4) carrying out vacuum defoaming on the uniformly mixed casting solution obtained in the step (3) to form a uniform casting solution, and then uniformly blade-coating the casting solution on a non-woven fabric by using a blade coater;
(5) placing the film subjected to blade coating in an environment with certain temperature and humidity for gas-phase induced phase separation to obtain a rough surface film structure, taking out the rough surface film structure, soaking the rough surface film structure in deionized water, and quenching and washing the first solvent and the second solvent; and taking out the cleaned OPBI membrane, and naturally airing to obtain the polybenzimidazole microporous membrane.
Preferably, in the step (1), the polybenzimidazole is a polybenzimidazole polymer having a weight average molecular weight in the range of 10000 to 1000000. The polybenzimidazole material in the molecular weight range has good solubility in organic solvent and good film-forming property.
Preferably, in the step (1), the first solvent is an organic agent with good compatibility with the polymer, and is selected from dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide or N-methylpyrrolidone; the mixing proportion is calculated according to the weight percentage, the dosage range of OPBI is as follows: 6 to 26 wt.%.
Preferably, the polybenzimidazole microporous membrane comprises a hollow fiber membrane and a flat membrane.
Preferably, in the step (2), the second solvent may be an organic solvent of ethyl acetate, isopropyl acetate, propylene glycol monomethyl ether acetate, acetone or petroleum ether, which is more soluble in the polymer.
Preferably, in step (3), the catalytic additive is an organotin selected from dibutyltin dilaurate DBTDL, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate or dibutyltin bis (dodecylthio) tin.
Preferably, in step (4), the dry film thickness is controlled by the wet film thickness.
Preferably, in the step (5), the humidity and the temperature can be controlled by a constant temperature and humidity chamber.
The second aspect of the present invention provides a method for improving acid resistance and stability of a polybenzimidazole microporous membrane, wherein the acid resistance is a retention capacity of hydrophobicity of the polybenzimidazole microporous membrane after acid soaking, and the stability is a retention capacity of hydrophobicity of the polybenzimidazole microporous membrane after oxidation by an oxidizing agent; the film forming conditions of the polybenzimidazole/hydrophobic polymer blending system are regulated and controlled by adjusting a gas-phase induced phase separation method, and the surface microstructure of the film is regulated and controlled, so that the surface of the hydrophilic material has a rough micro-surface structure to achieve a lasting high-hydrophobicity effect.
The third aspect of the present invention provides a method for improving the acid resistance and stability of a polybenzimidazole microporous membrane without affecting the mechanical properties, pore size distribution and size of the polybenzimidazole microporous membrane, wherein the acid resistance is the retention capacity of the polybenzimidazole microporous membrane after acid soaking for hydrophobicity, and the stability is the retention capacity of the polybenzimidazole microporous membrane after oxidation by an oxidizing agent; the film forming conditions of the polybenzimidazole/hydrophobic polymer blending system are regulated and controlled by adjusting a gas-phase induced phase separation method, and the surface microstructure of the film is regulated and controlled, so that the surface of the hydrophilic material has a rough micro-surface structure to achieve a lasting high-hydrophobicity effect.
The key points of the invention are as follows:
1. the synthesis process and synthesis conditions of the PBI polymer are adopted;
2. blending casting solution formula of polybenzimidazole hydrophobic microporous membrane;
3. the gas phase induced phase separation method is used for preparing OPBI hydrophobic microporous membranes, including hollow fiber membranes and flat membranes.
4. Regulating and controlling technological parameters of the surface structure of the polybenzimidazole microporous membrane by a gas-phase induced phase separation method;
5. a method for improving the stability of the surface microstructure of the polybenzimidazole microporous membrane by hydrophobic blending modification;
6. the prepared PBI hydrophobic microporous membrane can be used for the membrane distillation process of high-acidity solution;
compared with the prior art, the invention has the following beneficial effects:
1. the OPBI hydrophobic microporous membrane for membrane distillation is successfully prepared by a gas phase induced phase separation method, the cross section structure of the OPBI hydrophobic microporous membrane is a sponge pore structure (as shown in figure 8), the mechanical strength (tensile strength is between 30 and 60 Mpa) of the membrane is high, the porosity (65 to 85 percent) is high, and the average pore diameter is 0.10 to 0.25 mu m.
2. The polybenzimidazole microporous membrane with a surface micron coarse structure (shown in figures 6-7) is successfully prepared by adjusting the membrane forming conditions, wherein the key is the pre-evaporation temperature, so that the contact angle is more than or equal to 135 degrees, and the requirement of the membrane for membrane distillation is met.
3. According to the invention, by blending the hydrophobic materials, under the condition that the mechanical property, the pore size distribution and the size of the polybenzimidazole microporous membrane are not influenced, the contact angle is increased to about 145 degrees (as shown in figure 6-7 example 1), the superhydrophobic effect is basically achieved, the polybenzimidazole microporous membrane has good stability and acid resistance, after being soaked in 1mol/L nitric acid solution at 80 ℃ for 10 days, the tensile strength is 28-57Mpa, the hydrophobic contact angle is 134.5-140.3 degrees, and the polybenzimidazole microporous membrane can still be maintained at more than 130 degrees; the water-soluble film is soaked in a 1000ppm sodium hypochlorite solution at the temperature of 80 ℃ and the pH value is 5 for 7 days, the hydrophobic contact angle is 134.7-140.1 degrees, and the water-soluble film can still be kept at 130 degrees or more.
4. The OPBI hydrophobic microporous membrane prepared by the invention has higher concentration and separation performance on heavy metal solution with high acidity (0.2mol/L-1.0mol/L) and heavy metal retention rate>99.0% flux>12L·m-2·h-1。
5. The PBI hydrophobic microporous membrane prepared by the invention has better stability to high-acidity heavy metal solution, the membrane flux change rate is less than 20% after the PBI hydrophobic microporous membrane continuously operates for 15 days in acidic heavy metal solution with acidity of 0.2-1.0 mol/L, and the heavy metal interception can still be kept above 99.0%.
Drawings
FIG. 1 is a result of a hydrophobicity test of a sample obtained in comparative example 1;
FIG. 2 is a Scanning Electron Micrograph (SEM) of a sample obtained in comparative example 1;
FIG. 3 is a result of a hydrophobicity test of a sample obtained in comparative example 2;
FIG. 4 is a Scanning Electron Micrograph (SEM) of a sample obtained in comparative example 2;
FIG. 5 is a comparison of the hydrophobic stability of the samples obtained in comparative example 2;
FIG. 6 is a result of a hydrophobicity test of a sample obtained in example 1;
FIG. 7 is a Scanning Electron Micrograph (SEM) of a sample obtained in example 1;
FIG. 8 is a sectional view of a sample obtained in example 1.
Detailed Description
The present invention will be described below with reference to specific examples, but the embodiments of the present invention are not limited thereto. The experimental methods not specified in the examples are generally commercially available according to the conventional conditions and the conditions described in the manual, or according to the general-purpose equipment, materials, reagents and the like used under the conditions recommended by the manufacturer, unless otherwise specified. The starting materials required in the following examples and comparative examples are all commercially available.
Comparative example 1
Molecular weight 115000 formula
The aromatic ether type OPBI polymer (the melting point is 350 ℃) is prepared from N, N-dimethylacetamide and polybenzimidazole membrane casting solution with the solid content of 10%, and the polybenzimidazole membrane casting solution is placed into a vacuum defoaming machine for defoaming for standby after being uniformly mixed. Uniformly coating the casting solution on non-woven fabric with a 200um blade coater, exposing in air for 5min, and soaking in deionized waterAnd removing the solvent, and naturally airing for later use. The film surface can be seen by an electron microscope picture of the film surface that the film surface is very flat and has dense and hemp pores, and the contact angle is 90.2 degrees.
Comparative example 2
Molecular weight 115000 formula
The aromatic ether type OPBI polymer (the melting point is 350 ℃) is prepared by N, N-dimethylacetamide, polybenzimidazole casting solution with the solid content of 10% is prepared, and then the polybenzimidazole casting solution is placed into a vacuum defoaming machine for defoaming for standby. The constant temperature and humidity chamber was adjusted to 80 ℃ and the humidity was 100%. And uniformly coating the casting film liquid on the non-woven fabric by using a 200-micrometer blade coater, then placing the non-woven fabric in a constant temperature and humidity box for pre-evaporation for 5min, then taking out the non-woven fabric, soaking the non-woven fabric in deionized water to remove the solvent completely, and naturally airing for later use. The electron microscope image shows that the surface of the film is a filiform criss-cross rough structure, the hydrophobic property of the film can be effectively improved, however, the hydrophobic property is kept for a short time, and the contact angle is sharply reduced from 129.96 degrees to 56.9 degrees after 5 seconds.
Example 1
Molecular weight 115000 formula
Preparing a polybenzimidazole casting solution A with the solid content of 10% by using an aromatic ether type OPBI polymer (the melting point is 350 ℃) and an N, N-dimethylacetamide as a solvent, and then mixing Polydimethylsiloxane (PDMS), Tetraethoxysilane (TEOS) and Tetrahydrofuran (THF) according to the mass ratio of 3: 1: 30 are uniformly mixed to prepare a casting solution B, and the mixture is prepared according to the following steps of PDMS: OPBI 1: 20, mixing and stirring the membrane casting solution A and the membrane casting solution B for thirty minutes to ensure uniform mixing, wherein the mass ratio of PDMS: and (3) adding DBTDL into the mixed casting solution at a ratio of 6:1, and uniformly mixing. Then placing the mixture into a vacuum defoaming machine for defoaming for standby. The constant temperature and humidity chamber was adjusted to 80 ℃ and the humidity was 100%. And uniformly coating the casting film liquid on the non-woven fabric by using a 200-micrometer blade coater, then placing the non-woven fabric in a constant temperature and humidity box for pre-evaporation for 5min, then taking out the non-woven fabric, soaking the non-woven fabric in deionized water to remove the solvent completely, and naturally airing for later use. Making a businessAfter PDMS is combined, the film surface can be found to have the same rough structure as that in the comparative example 2 through an electron microscope image, and the hydrophobic property of the film is improved due to the blending of PDMS, the contact angle reaches 144.2 degrees, and the properties of the PBI hydrophobic microporous flat plate film prepared in the embodiment are as follows: the average pore diameter is 0.180 mu m, the porosity is 72.43%, the mechanical tensile strength is 46.59MPa, and the contact angle is 144.2 degrees. After the membrane is soaked in 1mol/L nitric acid solution for 10 days, the mechanical tensile strength of the membrane is 44.73MPa, and the contact angle is 140.3 degrees; after soaking in sodium hypochlorite solution (1000ppm, pH 5, 80 ℃) for 7 days, the film mechanical strength was 45.02MPa and the contact angle was 139.0 °. The super-hydrophobic OPBI-PDMS blended membrane is successfully obtained.
Example 2
Molecular weight 115000 formula
Preparing a polybenzimidazole casting solution A with the solid content of 10% by using an aromatic ether type OPBI polymer (the melting point is 350 ℃) and an N, N-dimethylacetamide as a solvent, and then mixing Polydimethylsiloxane (PDMS), Tetraethoxysilane (TEOS) and Tetrahydrofuran (THF) according to the mass ratio of 3: 1: 30 are uniformly mixed to prepare a casting solution B, and the mixture is prepared according to the following steps of PDMS: OPBI 1: 20, mixing and stirring the membrane casting solution A and the membrane casting solution B for thirty minutes to ensure uniform mixing, wherein the mass ratio of PDMS: and (3) adding DBTDL into the mixed casting solution at a ratio of 6:1, and uniformly mixing. Then placing the mixture into a vacuum defoaming machine for defoaming for standby. The constant temperature and humidity chamber was adjusted to 80 ℃ and the humidity was 100%. And uniformly coating the casting film liquid on the non-woven fabric by using a 200-micrometer blade coater, then placing the non-woven fabric in a constant temperature and humidity box for pre-evaporation for 5min, then taking out the non-woven fabric, soaking the non-woven fabric in deionized water to remove the solvent completely, and naturally airing for later use.
The PBI hydrophobic microporous flat membrane prepared by the embodiment has the following properties: the average pore diameter was 0.175. mu.m, the porosity was 74.85%, the mechanical tensile strength was 33.24MPa, and the contact angle was 142.6 °. After being soaked in 1mol/L nitric acid solution at the temperature of 80 ℃ for 10 days, the mechanical tensile strength of the membrane is 32.28MPa, and the contact angle is 138.7 degrees. Soaking in 1000ppm sodium hypochlorite solution at 80 deg.C and pH of 5 for 7 days, the mechanical tensile strength of the membrane is 32.55MPa, and the contact angle is 135.8 deg. The concentration of nitric acid is 0.3mol/L,The solution with the concentration of 60g/L of aluminum nitrate is simulated acidic heavy metal solution for vacuum membrane distillation, and the membrane flux is 13.28 L.m-2·h-1The retention rate of aluminum nitrate is 99.7 percent, and the membrane flux is 11.85 L.m after continuous operation for 15 days-2·h-1The retention rate of aluminum nitrate was 99.4%.
Example 3
Molecular weight 115000 formula
Preparing a polybenzimidazole casting solution A with the solid content of 12% by using an aromatic ether type PBI polymer (the melting point is 350 ℃) as a solvent N, N-dimethylacetamide, and then mixing Polydimethylsiloxane (PDMS), Tetraethoxysilane (TEOS) and Tetrahydrofuran (THF) according to the mass ratio of 3: 1: 30 are uniformly mixed to prepare a casting solution B, and the mixture is prepared according to the following steps of PDMS: OPBI 1: 10, mixing and stirring the membrane casting solution A and the membrane casting solution B for thirty minutes to ensure uniform mixing, wherein the mass ratio of PDMS: and (3) adding DBTDL into the mixed casting solution at a ratio of 6:1, and uniformly mixing. Then placing the mixture into a vacuum defoaming machine for defoaming for standby. The constant temperature and humidity chamber was adjusted to 80 ℃ and the humidity was 100%. And uniformly coating the casting film liquid on the non-woven fabric by using a 200-micrometer blade coater, then placing the non-woven fabric in a constant temperature and humidity box for pre-evaporation for 5min, then taking out the non-woven fabric, soaking the non-woven fabric in deionized water to remove the solvent completely, and naturally airing for later use.
The PBI hydrophobic microporous flat membrane prepared by the embodiment has the following properties: the average pore diameter was 0.168 μm, the porosity was 71.53%, the mechanical tensile strength was 36.37MPa, and the contact angle was 144.1 °. After being soaked in 1mol/L nitric acid solution at the temperature of 80 ℃ for 10 days, the mechanical tensile strength of the membrane is 34.73MPa, and the contact angle is 139.2. Soaking in 1000ppm sodium hypochlorite solution at 80 deg.C and pH of 5 for 7 days, the mechanical tensile strength of the membrane is 35.28MPa, and the contact angle is 140.1 deg. Vacuum membrane distillation is carried out by taking solution with 0.3mol/L nitric acid concentration and 60g/L aluminum nitrate concentration as simulated acidic heavy metal solution, and membrane flux is 12.65 L.m-2·h-1The retention rate of aluminum nitrate is 99.7 percent, and the membrane flux is 10.57 L.m after continuous operation for 15 days-2·h-1The retention rate of aluminum nitrate was 99.6%.
Example 4
Molecular weight 223000 formula
The preparation method comprises the following steps of (1) preparing a polybenzimidazole casting solution A with the solid content of 10% by using a PBI polymer (the melting point is 470 ℃) and N, N-dimethylacetamide as a solvent, and then mixing Polydimethylsiloxane (PDMS), Tetraethoxysilane (TEOS) and Tetrahydrofuran (THF) according to a mass ratio of 3: 1: 20, uniformly mixing to prepare a casting solution B, and mixing according to the mass ratio of PDMS: OPBI 1: 10, mixing and stirring the membrane casting solution A and the membrane casting solution B for thirty minutes to ensure uniform mixing, wherein the mass ratio of PDMS: and (3) adding DBTDL into the mixed casting solution at a ratio of 6:1, and uniformly mixing. Then placing the mixture into a vacuum defoaming machine for defoaming for standby. The constant temperature and humidity chamber was adjusted to 80 ℃ and the humidity was 100%. And uniformly coating the casting film liquid on the non-woven fabric by using a 200-micrometer blade coater, then placing the non-woven fabric in a constant temperature and humidity box for pre-evaporation for 5min, then taking out the non-woven fabric, soaking the non-woven fabric in deionized water to remove the solvent completely, and naturally airing for later use.
The PBI hydrophobic microporous flat membrane prepared by the embodiment has the following properties: the average pore diameter was 0.180. mu.m, the porosity was 72.43%, the mechanical tensile strength was 36.15MPa, and the contact angle was 138.6 °. After being soaked in 1mol/L nitric acid solution for 10 days, the mechanical tensile strength of the membrane is 34.58MPa, and the contact angle is 134.5 degrees. Soaking in 1000ppm sodium hypochlorite solution at 80 deg.C and pH of 5 for 7 days, the mechanical tensile strength of the membrane is 35.43MPa, and the contact angle is 134.7 deg. Vacuum membrane distillation is carried out by taking solution with 0.3mol/L nitric acid concentration and 60g/L aluminum nitrate concentration as simulated acidic heavy metal solution, and the membrane flux is 14.73 L.m-2·h-1The retention rate of aluminum nitrate is 99.7 percent, and the membrane flux is 12.66 L.m after continuous operation for 15 days-2·h-1The retention rate of aluminum nitrate was 99.8%.
Claims (10)
1. The polybenzimidazole microporous membrane with high acid resistance and high stability is characterized by comprising a hollow fiber membrane or a flat membrane, wherein the polybenzimidazole microporous membrane has the tensile strength of 30-60Mpa, the porosity of 65-85%, the average pore diameter of 0.10-0.25 mu m and the hydrophobic contact angle of 145 DEG; the tensile strength of the product is 28-57Mpa after the product is soaked in 1mol/L nitric acid solution, the hydrophobic contact angle can still be kept above 130 degrees, and the hydrophobic contact angle can still be kept above 130 degrees after the product is soaked in 5 pH sodium hypochlorite solution.
2. A preparation method of a polybenzimidazole microporous membrane with high acid resistance and high stability is characterized by comprising the following steps:
(1) mixing polybenzimidazole OPBI with a first solvent to prepare a membrane casting solution A;
(2) dissolving polydimethylsiloxane PDMS and tetraethoxysilane TEOS into a second solvent of tetrahydrofuran THF to form a membrane casting solution B;
(3) mixing and stirring the membrane casting solution A and the membrane casting solution B according to a certain proportion, and then adding a catalyst for mixing;
(4) carrying out vacuum defoaming on the membrane casting solution mixed in the step (3), and then scraping and coating the membrane casting solution on non-woven fabrics by using a scraping coater;
(5) and (3) placing the film subjected to blade coating in an environment with certain temperature and humidity for gas-phase induced phase separation to obtain a film with a rough surface structure, taking out, quenching, washing and drying to obtain the polybenzimidazole microporous film.
3. The method for preparing a polybenzimidazole microporous membrane with high acid resistance and high stability according to claim 2, wherein in the step (1), the polybenzimidazole is a polybenzimidazole polymer having a weight average molecular weight ranging from 10000 to 1000000.
4. The method for preparing a polybenzimidazole microporous membrane with high acid resistance and high stability according to claim 2, wherein in the step (1), the first solvent is an organic reagent with good compatibility with the polymer, and is selected from dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide or N-methylpyrrolidone; the mixing proportion is calculated according to the weight percentage, the dosage range of OPBI is as follows: 6 to 26 wt.%.
5. The method for preparing a polybenzimidazole microporous membrane with high acid resistance and high stability according to claim 2, wherein in the step (2), the second solvent is an organic solvent such as ethyl acetate, isopropyl acetate, propylene glycol monomethyl ether acetate, acetone or petroleum ether, which has good solubility in the polymer.
6. The method for preparing the polybenzimidazole microporous membrane with high acid resistance and high stability according to claim 2, wherein in the step (3), the catalyst is organic tin selected from dibutyltin dilaurate DBTDL, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate or dibutyltin didodecyl sulfide.
7. The method for preparing a polybenzimidazole microporous membrane with high acid resistance and high stability according to claim 2, wherein in the step (4), the dry membrane thickness in the final product is controlled by controlling the wet membrane thickness in the step.
8. The method for preparing a polybenzimidazole microporous membrane with high acid resistance and high stability according to claim 2, wherein in the step (5), the humidity and temperature during the gas phase induced phase separation can be controlled by a constant temperature and humidity chamber, and the quenching, washing and drying are performed by taking out and soaking the polybenzimidazole microporous membrane in deionized water to quench and wash the first solvent and the second solvent; and taking out the cleaned OPBI membrane, and naturally airing to obtain the polybenzimidazole microporous membrane.
9. The method for improving the acid resistance and the stability of the polybenzimidazole microporous membrane is characterized in that the acid resistance is the retention capacity of the polybenzimidazole microporous membrane after being soaked in acid and the stability is the retention capacity of the polybenzimidazole microporous membrane after being oxidized by an oxidant; the film forming conditions of the polybenzimidazole/hydrophobic polymer blending system are regulated and controlled by adjusting a gas-phase induced phase separation method, and the surface microstructure of the film is regulated and controlled, so that the surface of the hydrophilic material has a rough micro-surface structure to achieve a lasting high-hydrophobicity effect.
10. A method for improving the acid resistance and the stability of a polybenzimidazole microporous membrane under the condition of not influencing the mechanical property, the pore size distribution and the size of the polybenzimidazole microporous membrane is characterized in that the acid resistance is the retention capacity of the polybenzimidazole microporous membrane after being soaked by acid and the stability is the retention capacity of the polybenzimidazole microporous membrane after being oxidized by an oxidizing agent; the film forming conditions of the polybenzimidazole/hydrophobic polymer blending system are regulated and controlled by adjusting a gas-phase induced phase separation method, and the surface microstructure of the film is regulated and controlled, so that the surface of the hydrophilic material has a rough micro-surface structure to achieve a lasting high-hydrophobicity effect.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20010014603A (en) * | 1999-03-19 | 2001-02-26 | 로데릭 제이. 레이 | Solvent-resistant microporous polybenzimidazole membranes |
| WO2013103537A1 (en) * | 2012-01-04 | 2013-07-11 | Momentive Performance Materials Inc. | Silicone adhesive compositions |
| CN104147947A (en) * | 2014-08-14 | 2014-11-19 | 娄尤来 | Preparation method of PDMS/PAN composite hollow fiber membrane |
| CN107146903A (en) * | 2016-05-13 | 2017-09-08 | 宁波市智能制造产业研究院 | A kind of polymer electrolyte membrane for fuel cell |
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2021
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20010014603A (en) * | 1999-03-19 | 2001-02-26 | 로데릭 제이. 레이 | Solvent-resistant microporous polybenzimidazole membranes |
| WO2013103537A1 (en) * | 2012-01-04 | 2013-07-11 | Momentive Performance Materials Inc. | Silicone adhesive compositions |
| CN104147947A (en) * | 2014-08-14 | 2014-11-19 | 娄尤来 | Preparation method of PDMS/PAN composite hollow fiber membrane |
| CN107146903A (en) * | 2016-05-13 | 2017-09-08 | 宁波市智能制造产业研究院 | A kind of polymer electrolyte membrane for fuel cell |
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