CN110368823B - Preparation method of metal organic framework-polyimide composite fiber membrane material - Google Patents
Preparation method of metal organic framework-polyimide composite fiber membrane material Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/54—Particle separators, e.g. dust precipitators, using ultra-fine filter sheets or diaphragms
- B01D46/543—Particle separators, e.g. dust precipitators, using ultra-fine filter sheets or diaphragms using membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
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- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
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- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/58—Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
- B01D71/62—Polycondensates having nitrogen-containing heterocyclic rings in the main chain
- B01D71/64—Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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Abstract
The invention relates to a preparation of a metal organic frame-polyimide composite fiber membrane material, which comprises the steps of firstly preparing ZIF-8 in a methanol system by a room temperature rapid method, then carrying out imidization reaction to prepare soluble polyimide 6FDA-BDAF, and then preparing a ZIF/PI composite fiber membrane by utilizing a simple electrostatic spinning technology, wherein the prepared membrane material has higher thermal stability and mechanical strength, is an interconnected network structure formed by randomly distributing nano fibers, has the diameter range of 200-300 nanometers, is well dispersed in a PI matrix without obvious phenomenon, and has the advantages that the originally smooth fiber surface becomes rough along with the addition of ZIF-8 agglomeration, the occurrence frequency of superfine fibers is increased, the specific surface area of the material is increased, the material has stronger capability of capturing PM2.5, and the preparation method is simple and convenient, the method has the advantages of mild and easily-controlled reaction conditions, contribution to large-scale production, good performance and simple and convenient preparation method, and wide application prospect in the field of high-temperature air filtration.
Description
Technical Field
The invention relates to the technical field of functional material preparation, in particular to a preparation method of a metal organic framework-polyimide composite fiber membrane material.
Background
Polyimide (PI) is a class of organic polymers with main chains containing imide rings, is one of organic polymer materials with the best comprehensive performance, has the advantages of high insulating performance, high mechanical strength, high thermal stability, wear resistance and the like, and is widely applied to the fields of aviation, aerospace, microelectronics, nano, liquid crystal, separation membranes, lasers and the like. In addition, the polyimide also has high dipole moment (reaching 6.2D) which is much higher than that of a common active capture polymer, so that the polyimide has extremely strong PM2.5 capture capacity, and the excellent physical and chemical properties of the polyimide also promote the application of the polyimide in the field of air filtration.
Conventional air filtration materials tend to increase filtration efficiency by increasing the bulk density or decreasing the fiber pore size, however this operation increases air flow resistance and causes discomfort to the user; with the development of science and technology, people put forward higher requirements on air filtering materials, and besides PM filtering efficiency and pressure resistance, thermal stability, mechanical properties and the like also become important indexes for measuring novel filtering materials. The polyimide fiber membrane has excellent thermal stability and mechanical property, is subjected to functional modification, further improves the filtering capacity of the polyimide fiber membrane to PM2.5 on the premise of not damaging the original performance, can broaden the application prospect of the polyimide filtering material in the field of air filtration, and provides a feasible way for PM pollution control.
Metal-Organic Frameworks (MOFs) are framework structures composed of Metal ions and Organic ligands. Some MOF materials not only have the characteristics of large specific surface area, structural and pore diversity, functional adjustability and the like, but also show high PM2.5 capture capacity. In recent years, the combination of MOF material and polymer has become a research hotspot of novel air filtering material, and the american journal of chemistry (j.am.chem.soc.2016, 138, 5785-; journal of Chemical Engineering (Chemical Engineering Journal 2018, 338, 82-91.) reports a ZIF-8/polylactic acid composite fiber membrane material, and as polylactic acid and ZIF-8 have good interfacial interaction, PM filtration efficiency of the composite membrane is further improved on the premise of not damaging the performance of a matrix, but polylactic acid has poor heat resistance and mechanical properties and cannot be used in a severe working environment.
In combination with the above, the advantages of the polyimide material and the metal organic frame are combined, and a metal organic frame-polyimide composite fiber membrane material is provided, which is a hot point of research in the prior art, but in the prior art, an in-situ composite method is mostly adopted for the compounding of the polyimide and the metal organic frame, so that not only the mechanical properties are affected due to poor binding capacity of the polyimide and the metal organic frame, but also the preparation process is complex and difficult to operate, and therefore, how to provide a simpler and more convenient process for preparing the metal organic frame-polyimide composite fiber membrane material is how to provide a metal organic frame-polyimide composite fiber membrane material, so that the metal organic frame-polyimide composite fiber membrane material not only has good PM pollutant filtering capacity, but also has low piezoresistance, higher heat resistance and better mechanical property and.
Disclosure of Invention
In view of the above, the invention provides a preparation method of a metal organic framework-polyimide composite fiber membrane material, which utilizes an electrostatic spinning technology to perform electrospinning on a metal organic framework and polyimide mixed material, so that the metal organic framework and the polyimide mixed material have better binding capacity, thus having better mechanical properties and simpler and more convenient preparation process.
In order to achieve the purpose, the invention specifically adopts the following technical means:
the preparation method of the metal organic framework-polyimide composite fiber membrane material is characterized by comprising the following steps:
the method comprises the following steps: preparation of metal organic framework ZIF-8
Respectively dissolving a certain amount of dimethylimidazole and zinc nitrate in methanol, mixing the two solutions, standing for 24 hours, cleaning with methanol, performing centrifugal separation, and drying in an oven at 120 ℃ for 12 hours to obtain ZIF-8;
step two: preparation of soluble polyimide 6FDA-BDAF
(2.1) dissolving hexafluoropropane in N, N-dimethylacetamide under the conditions of nitrogen and ice water bath, adding hexafluoro dianhydride into the mixed solution after the hexafluoropropane is completely dissolved to obtain a solid-containing mixed solution, and then continuously stirring the solid-containing mixed solution for 1 h;
(2.2) removing the solid-containing mixed solution out of the ice-water bath, continuously stirring for 20 hours at room temperature, adding acid anhydride and pyridine, and continuously stirring for 20 hours to obtain a viscous solution;
(2.3) pouring the viscous solution into excessive absolute ethyl alcohol to obtain filamentous resin, collecting the filamentous resin, and drying at 80 ℃ for 24 hours to obtain soluble polyimide 6 FDA-BDAF;
step three: preparation of metal organic frame-polyimide composite fiber membrane material
(3.1) dissolving the metal organic framework ZIF-8 prepared in the first step in N, N-dimethylacetamide, ultrasonically dispersing for 6 hours, adding the soluble polyimide 6FDA-BDAF prepared in the second step, stirring for 1-3 hours at room temperature after completely dissolving to obtain a mixed solution;
and (3.2) moving the mixed solution into an electrostatic spinning device, taking an aluminum foil as a collector, setting electrostatic spinning parameters, carrying out electrospinning for 1-2h, and then removing the electrospinning membrane, namely the metal organic framework-polyimide composite fiber membrane material.
Preferably, the molar ratio of the dimethyl imidazole to the zinc nitrate in the first step is (2-8) to 1.
The beneficial effects of the preferred technical scheme are as follows: the proportion of dimethylimidazole and zinc nitrate is changed, the particle size of ZIF-8 can be changed, but the formation of electrospun fibers can be influenced when the particle size of ZIF-8 is too large, and serious agglomeration can occur when the particle size is too small.
Preferably, the centrifugation speed in the first step is 10000rpm, the centrifugation time is 10min, and the cleaning-centrifugation process is repeated more than twice.
Preferably, the mole ratio of the hexafluoropropane, the N, N-dimethylacetamide and the hexafluorodianhydride in the step (2.1) is 1:63: 1.
The beneficial effects of the preferred technical scheme are as follows: the mole ratio of the hexafluoropropane to the hexafluorodianhydride is 1: 1, the hexafluoropropane and the hexafluorodianhydride are alternately chained, the polymerization degree is high, the product performance is excellent, and when the mole ratio of the hexafluoropropane to the hexafluorodianhydride is not 1: 1, the polymerization degree is low, residual monomer impurities exist, and the product performance is poor.
Preferably, the acid anhydride added in the step (2.2) is 7.9 wt% of the solid-containing solution, and the pyridine is 6.2 wt% of the solid-containing solution in terms of weight ratio.
The beneficial effects of the preferred technical scheme are as follows: the addition of too little acid anhydride and pyridine can result in low imidization degree of the product, and the addition of too high amount can not influence the product but cause waste of reagents.
Preferably, the mass ratio of the soluble polyimide 6FDA-BDAF, the metal organic framework ZIF-8 and the N, N-dimethylacetamide added in the step (3.1) is 0.4 to (0.01-0.04) to 2.
Preferably, the process parameters of the coaxial electrospinning in the step (3.2) are as follows: the distance between the receiver and the injection port of the spinning device is 15cm, the spinning voltage is 15kV, the environmental humidity is less than 40 percent, and the temperature is 20-30 ℃.
The beneficial effects of the preferred technical scheme are as follows: the selection of the spinning voltage and the spinning distance has great influence on film forming, the receiving of the receiver on spinning is influenced by overhigh voltage or overlong distance along with the rise of the spinning voltage and the increase of the spinning distance, the film forming effect is influenced, the liquid in the spinning solution with overhigh humidity and overlow temperature is difficult to volatilize, the liquid in the spinning solution with overhigh temperature and overlow temperature is difficult to receive by the receiver, and the integrality of the formed film is influenced.
In summary, compared with the prior art, the invention has the following technical effects:
the invention combines the advantages of high ZIF-8Zeta potential and good thermal stability of a metal frame structure, high mechanical strength and good thermal stability of a polyimide material, good PM2.5 capture capacity and the like, and the prepared ZIF/PI membrane not only retains the advantages of high mechanical property and thermal stability of the polyimide fiber membrane, but also further improves the PM2.5 filtration efficiency of the composite fiber membrane.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic diagram of an XRD diffraction pattern of ZIF-8 prepared in accordance with the present invention;
FIG. 2 is a scanning electron micrograph of ZIF-8 made in accordance with the present invention;
FIG. 3 is a drawing showing an IR spectrum of a soluble polyimide 6FDA-BDAF prepared by the present invention;
FIG. 4 is an SEM/EDS view of a PI-ZIF-10 composite fiber prepared according to the present invention;
FIG. 5 is a graph showing the thermogravimetric plot of the PI-ZIF composite fiber prepared by the present invention;
FIG. 6 is a graph showing a test of filtration performance of a PI-ZIF composite fiber according to the present invention;
FIG. 7 is a graph showing a filtering performance test of a PI-ZIF composite fiber obtained by the heat treatment of the present invention;
FIG. 8 is a graph showing the stress-strain curves of PI-ZIF composite fibers made in accordance with the present invention;
FIG. 9 is a graph of wind velocity-pressure drop for PI-ZIF composite fibers made in accordance with the present invention;
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Preparation of metal organic framework ZIF-8
1.621g (20mol) of dimethylimidazole and 1.291g (4.3mol) of zinc nitrate are respectively dissolved in 50ml of methanol, then the two solutions are mixed and stood for 24h, washed by methanol, centrifuged at 10000rpm for 10min, washed and centrifuged twice repeatedly, and then dried in an oven at 120 ℃ for 12h to obtain the ZIF-8.
The prepared ZIF-8 is characterized, and as can be seen from figure 1, the diffraction spectrum of the product prepared by the method is completely consistent with the known standard diffraction spectrum, which shows that the product is ZIF-8; as can be seen from the scanning electron microscope image in FIG. 2, the ZIF-8 particles prepared by the method have equidistant nanoparticles with sharp edges and narrow particle size distribution, and the statistical evaluation of 100 particles shows that the average diameter is 95 nanometers and the morphology is good;
after the ZIF-8 prepared by the invention is subjected to heat treatment at 300 ℃ for 1h, the original crystal structure can be still maintained, which shows that the ZIF-8 has excellent thermal stability.
Example 2
Preparation of soluble polyimide 6FDA-BDAF
(2.1) dissolving 5.185g (10mol) of hexafluoropropane in 54.6g (630mol) of N, N-dimethylacetamide under the conditions of nitrogen and ice water bath, adding 4.442g (10mol) of hexafluoro dianhydride into the mixed solution after the hexafluoropropane is completely dissolved to obtain a mixed solution with the solid content of 15 wt%, and then continuously stirring the solid-containing mixed solution for 1 h;
(2.2) removing the solid-containing mixed solution from the ice-water bath, continuously stirring for 20 hours at room temperature, adding 5.1g of acid anhydride and 4.0g of pyridine, and continuously stirring for 20 hours to obtain a viscous solution;
and (2.3) pouring the viscous solution into excessive absolute ethyl alcohol to obtain filamentous resin, collecting the filamentous resin, and drying at 80 ℃ for 24 hours to obtain the soluble polyimide 6 FDA-BDAF.
The infrared spectrum of the soluble polyimide obtained above was characterized, and the result is shown in FIG. 3, which shows that the concentration of the soluble polyimide in the sample is 1786cm-1Asymmetric stretching vibration near C ═ O bond, 1727cm-1Symmetric stretching vibration of C ═ O bond nearby, 723cm-1The vicinity corresponds to a modification of the imine ring, 1375cm-1Stretching vibration with C-N bond near the center, and 3363cm-1(N-H stretching vibration) and 1650cm-1The absorption peak of (amide C ═ O stretching vibration) disappeared, indicating that 6FDA-BDAF achieved a complete imidization process.
Example 3
Preparation of metal organic frame-polyimide composite fiber membrane material
(3.1) dissolving the metal organic framework ZIF-80.01 g prepared in the example 1 in 2g of N, N-dimethylacetamide, ultrasonically dispersing for 6h, adding 0.4g of the soluble polyimide 6FDA-BDAF prepared in the example 2, stirring for 1-3h at room temperature after completely dissolving to obtain a mixed solution;
and (3.2) transferring the mixed solution into an electrostatic spinning device, taking an aluminum foil as a collector, electrically spinning the receiver and an injection port of a spinner at the distance of 15cm, the spinning voltage of 15kV and the ambient humidity of less than 40 percent at the temperature of 20-30 ℃ for 1-2h, and then removing the electrically spun film to obtain the metal organic framework-polyimide composite fiber film material.
Wherein the load of ZIF-8 is 2.5 wt% of 6FDA-BDAF, and is marked as PI-ZIF-2.5.
Example 4
Preparation of metal organic frame-polyimide composite fiber membrane material
(3.1) dissolving 80.02 g of the metal organic framework ZIF prepared in the example 1 in 2g of N, N-dimethylacetamide, ultrasonically dispersing for 6h, adding 0.4g of the soluble polyimide 6FDA-BDAF prepared in the example 2, and stirring for 1-3h at room temperature after completely dissolving to obtain a mixed solution;
and (3.2) transferring the mixed solution into an electrostatic spinning device, taking an aluminum foil as a collector, electrically spinning the receiver and an injection port of a spinner at the distance of 15cm, the spinning voltage of 15kV and the ambient humidity of less than 40% at the temperature of 20-30 ℃ for 1-2h, and then removing the electrically spun film to obtain the ZIF-8 metal organic framework-polyimide composite fiber film material with the load of 5 wt%.
Wherein the load of ZIF-8 is 5 wt% of 6FDA-BDAF, and is marked as PI-ZIF-5.
Example 5
Preparation of metal organic frame-polyimide composite fiber membrane material
(3.1) dissolving the metal organic framework ZIF-80.03 g prepared in the example 1 in 2g of N, N-dimethylacetamide, ultrasonically dispersing for 6h, adding 0.4g of the soluble polyimide 6FDA-BDAF prepared in the example 2, stirring for 1-3h at room temperature after completely dissolving to obtain a mixed solution;
and (3.2) transferring the mixed solution into an electrostatic spinning device, taking an aluminum foil as a collector, electrically spinning the receiver and an injection port of a spinner at the distance of 15cm, the spinning voltage of 15kV and the ambient humidity of less than 40% at the temperature of 20-30 ℃ for 1-2h, and then removing the electrically spun film to obtain the ZIF-8 metal organic framework-polyimide composite fiber film material with the load of 7.5 wt%.
Wherein, the load of ZIF-8 is 7.5 wt% of 6FDA-BDAF, and is marked as PI-ZIF-7.5.
Example 6
Preparation of metal organic frame-polyimide composite fiber membrane material
(3.1) dissolving the metal organic framework ZIF-80.04 g prepared in the example 1 in 2g of N, N-dimethylacetamide, ultrasonically dispersing for 6h, adding 0.4g of the soluble polyimide 6FDA-BDAF prepared in the example 2, stirring for 1-3h at room temperature after completely dissolving to obtain a mixed solution;
and (3.2) transferring the mixed solution into an electrostatic spinning device, taking an aluminum foil as a collector, electrically spinning the receiver and an injection port of a spinner at the distance of 15cm, the spinning voltage of 15kV and the ambient humidity of less than 40% at the temperature of 20-30 ℃ for 1-2h, and then removing the electrically spun film to obtain the ZIF-8 metal organic framework-polyimide composite fiber film material with the load of 10 wt%.
Wherein, the load of ZIF-8 is 10 wt% of 6FDA-BDAF, and is marked as PI-ZIF-10.
Example 7
The metal organic framework-polyimide composite fiber membrane material prepared in the above embodiment is subjected to a functionality test, and the test process and results are as follows:
1. thermal stability test
The thermal stability of the nanofiber membrane is determined by the weight change of the sample under the process of continuously increasing the temperature, in the test, 3mg of the metal organic framework-polyimide composite fiber membrane material is weighed, the metal organic framework-polyimide composite fiber membrane material is heated to 800 ℃ from room temperature at the heating rate of 10 ℃/min in the air atmosphere, and the thermal weight loss curve of the sample is drawn according to the mass of the sample at different temperatures, as shown in the attached figure 5.
FIG. 5 shows that decomposition of PI (6FDA-BDAF) and ZIF-8 occurred at the earliest at 450 ℃ and 400 ℃ respectively, and that both materials exhibited excellent thermal stability, while the decomposition temperature of the complex PI-ZIF-10 of both was similar to that of ZIF-8, and decomposition started at 400 ℃ due to the first decomposition of ZIF-8 in the complex.
2. Filtration efficiency test
The air filtration performance of the nanofiber membrane is determined by the content change of fine particles in air before and after the filtration of the corresponding nanofiber membrane, and in the test, a proper test environment (the PM2.5 concentration is more than 200 mu g/m) is created by burning cigarettes in a closed space3) Firstly, an aerosol detector is used for measuring and recording the PM2.5 concentration in the air. Subsequently, the PI-ZIF composite fiber membrane to be tested was placed at the air inlet of the tester to ensure sufficient sealing, and then the meter reading was recorded, and the filtration efficiency was obtained by comparing the filtered PM2.5 concentration with the PM2.5 concentration in air, and the measured filtration efficiency was as shown in fig. 6.
FIG. 6 shows that the filtration efficiency of the pure PI membrane is 83.2%, and with the addition of ZIF-8, the filtration efficiency of the PI-ZIF membrane is significantly improved to 94.4%, 96.4%, and 96.6%, respectively. The ZIF-8 has high Zeta potential, and the surface charge of the ZIF-8 can perform electrostatic interaction with polar pollutants in the air, so that PM particles are adsorbed to the fibers, and the capability of the fibers for capturing the particles is improved.
In addition, the filtration efficiency of the fiber membranes after heat treatment at different temperatures (100 ℃, 200 ℃, 300 ℃, 1h) was also tested, and as a result, as shown in fig. 7, the filtration efficiency of the fiber membranes after heat treatment was substantially consistent with that before heat treatment, which further confirmed the high thermal stability of the fiber membranes and maintained the high filtration efficiency even after high temperatures.
3. Mechanical Property test
The mechanical properties of nanofiber membranes are typically evaluated using tensile testing. In the test, a PI-ZIF composite fiber membrane is cut into a 2 x 15mm long strip, the strip is stretched across a paper U-shaped support, two ends of a sample are fixed by using glue, the distance between two arms of the support is 5mm, then the two arms of the support are respectively fixed on an upper clamp and a lower clamp of a mechanical experiment machine, the stretching is carried out at a stretching rate of 1mm/min, a load-displacement curve is obtained, and the stress-strain curve of the fiber membrane can be obtained by calculating the load/sectional area and the original length of the displacement/sample, as shown in an attached figure 8.
FIG. 8 shows that, after ZIF-8 is added, although the tensile strength and the elongation of the composite fiber membrane are reduced as a whole, the weakened PI-ZIF composite membrane still has considerable strength and elongation because PI has excellent mechanical properties. In addition, the addition of the ZIF-8 also improves the rigidity of the fiber membrane, the fibers are oriented in the stretching direction in the initial stretching stage, the deformation is easy, the modulus of PI and PI-ZIF-10 is respectively 6MPa and 4.7MPa, then the fibers are arranged along the stretching direction, the deformation is difficult, the modulus of PI and PI-ZIF-10 is respectively increased to 10.7MPa and 29.2MPa, and the high modulus enables the fibers to have better deformation resistance and self-supporting capability.
4. Pressure drop Performance test
In nanofiber membranes, the pressure drop across the fiber membrane is caused by the resistance of the fibers to the flow of gas through the fiber membrane. The pressure drop across a fiber membrane is a function of its thickness, volume fraction of solids, air viscosity and superficial velocity. The constant air flow flows through the fiber membrane, the pressure difference between the two sides of the membrane is measured by a pressure difference meter, and the measured pressure difference is the pressure drop. In the test, the wind speed-pressure drop curve of the fiber membrane is drawn by changing the gas flow speed, as shown in figure 9, the pressure drop of the fiber membrane is basically unchanged before and after the ZIF-8 is added, which shows that the filtering performance of the membrane is obviously improved on the premise of not causing the increase of the fiber resistance due to the addition of the ZIF-8. Furthermore, by comparison with two commercial filtration membranes, it was found that the pressure drop for all membranes was between the two, indicating that the fibrous membranes meet the pressure drop requirements of current commercial filters.
In conclusion, the composite fiber membrane prepared by the invention meets the relevant requirements and has excellent performance.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. The preparation method of the metal organic framework-polyimide composite fiber membrane material is characterized by comprising the following steps:
the method comprises the following steps: preparation of metal organic framework ZIF-8
Respectively dissolving a certain amount of dimethylimidazole and zinc nitrate in methanol, mixing the two solutions, standing for 24 hours, washing with methanol, centrifugally separating, and drying to obtain ZIF-8;
step two: preparation of soluble polyimide 6FDA-BDAF
(2.1) dissolving hexafluoropropane in N, N-dimethylacetamide under the conditions of nitrogen and ice water bath, adding hexafluoro dianhydride into the mixed solution after the hexafluoropropane is completely dissolved to obtain a solid-containing mixed solution, and then continuously stirring the solid-containing mixed solution for 1 h;
(2.2) removing the solid-containing mixed solution out of the ice-water bath, continuously stirring for 20 hours at room temperature, adding acid anhydride and pyridine, and continuously stirring for 20 hours to obtain a viscous solution;
(2.3) pouring the viscous solution into excessive absolute ethyl alcohol to obtain filamentous resin, collecting the filamentous resin, and drying to obtain soluble polyimide 6 FDA-BDAF;
step three: preparation of metal organic frame-polyimide composite fiber membrane material
(3.1) dissolving the metal organic framework ZIF-8 prepared in the first step in N, N-dimethylacetamide, ultrasonically dispersing for 6 hours, adding the soluble polyimide 6FDA-BDAF prepared in the second step, stirring for 1-3 hours at room temperature after completely dissolving to obtain a mixed solution;
(3.2) moving the mixed solution into an electrostatic spinning device, taking an aluminum foil as a collector, setting electrostatic spinning parameters, then carrying out electrospinning for 1-2h, and then removing an electrospinning membrane, namely the metal organic framework-polyimide composite fiber membrane material;
the molar ratio of the dimethyl imidazole to the zinc nitrate in the first step is (2-8): 1;
the electrostatic spinning parameters in the step (3.2) are as follows: the distance between the receiver and the injection port of the spinning device is 15cm, the spinning voltage is 15kV, the environmental humidity is less than 40 percent, and the temperature is 20-30 ℃;
the mass ratio of the soluble polyimide 6FDA-BDAF, the metal organic framework ZIF-8 and the N, N-dimethylacetamide added in the step (3.1) is 0.4: (0.01-0.04): 2.
2. the preparation method of the metal organic framework-polyimide composite fiber membrane material as claimed in claim 1, wherein the centrifugation speed in the first step is 10000rpm, the centrifugation time is 10min, and the cleaning-centrifugation process is repeated more than twice.
3. The preparation method of the metal organic framework-polyimide composite fiber membrane material as claimed in claim 1, wherein the drying in the first step is drying in an oven at 120 ℃ for 12 h.
4. The preparation method of the metal organic framework-polyimide composite fiber membrane material as claimed in claim 1, wherein the molar ratio of hexafluoropropane, N-dimethylacetamide and hexafluorodianhydride in the step (2.1) is 1:63: 1.
5. The preparation method of the metal organic framework-polyimide composite fiber membrane material as claimed in claim 1, wherein the acid anhydride added in the step (2.2) is 7.9 wt% of the solid-containing solution, and the pyridine is 6.2 wt% of the solid-containing solution according to the weight ratio.
6. The preparation method of the metal organic framework-polyimide composite fiber membrane material as claimed in claim 1, wherein the drying in the step (2.3) is drying at 80 ℃ for 24 h.
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| CN112717711A (en) * | 2020-12-14 | 2021-04-30 | 中海石油(中国)有限公司 | Preparation method of polyimide-based mixed matrix hollow fiber membrane |
| CN112853759B (en) * | 2021-02-03 | 2022-01-07 | 北京航空航天大学 | Metal organic framework core-shell fiber material and preparation method thereof |
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| CN115323626B (en) * | 2022-08-30 | 2023-11-14 | 暨南大学 | Polymer and functional complex composite thermal management material and preparation method and application thereof |
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| CN115976735B (en) * | 2022-12-19 | 2023-12-08 | 南京理工大学 | Composite polylactic acid fiber membrane containing self-charged nano antibacterial agent, preparation method and application thereof |
| CN116987400B (en) * | 2023-09-27 | 2024-01-23 | 紫晶电子材料(杭州)有限公司 | Liquid crystal polymer composite material and preparation method and application thereof |
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| CN106988017B (en) * | 2017-03-20 | 2019-04-12 | 南京理工大学 | A kind of high adsorption porous compound film and preparation method thereof for adsorbing PM2.5 |
| US10188981B2 (en) * | 2017-04-21 | 2019-01-29 | King Fahd University Of Petroleum And Minerals | Mixed matrix membrane, a method of making thereof, and a method for gas separation |
| CN107201645A (en) * | 2017-04-28 | 2017-09-26 | 东华大学 | A kind of metal organic frame/carbon nano-fiber composite film material and preparation method thereof |
| JP2019018178A (en) * | 2017-07-20 | 2019-02-07 | 旭化成株式会社 | Separation membrane |
| CN109135220B (en) * | 2018-06-29 | 2020-07-24 | 南京理工大学 | Polylactic acid/ZIF-8 @ C600 composite material and preparation method and application thereof |
| CN108822544B (en) * | 2018-07-09 | 2020-11-03 | 陕西科技大学 | Preparation method of polyimide/metal organic framework composite film |
| CN108893863B (en) * | 2018-08-14 | 2020-10-09 | 华南协同创新研究院 | ZIF-8/polyvinylidene fluoride composite nanofiber membrane and preparation method and application thereof |
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