CN117679965A - Method for preparing polyamide hollow fiber membrane by thermally induced phase separation - Google Patents
Method for preparing polyamide hollow fiber membrane by thermally induced phase separation Download PDFInfo
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- CN117679965A CN117679965A CN202311731584.5A CN202311731584A CN117679965A CN 117679965 A CN117679965 A CN 117679965A CN 202311731584 A CN202311731584 A CN 202311731584A CN 117679965 A CN117679965 A CN 117679965A
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- fiber membrane
- polyamide
- hollow fiber
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- 239000012528 membrane Substances 0.000 title claims abstract description 133
- 239000012510 hollow fiber Substances 0.000 title claims abstract description 110
- 239000004952 Polyamide Substances 0.000 title claims abstract description 107
- 229920002647 polyamide Polymers 0.000 title claims abstract description 107
- 238000000034 method Methods 0.000 title claims abstract description 30
- 238000002145 thermally induced phase separation Methods 0.000 title claims abstract description 27
- 238000004140 cleaning Methods 0.000 claims abstract description 39
- 239000002245 particle Substances 0.000 claims abstract description 37
- 239000003085 diluting agent Substances 0.000 claims abstract description 23
- 238000005266 casting Methods 0.000 claims abstract description 21
- 239000004793 Polystyrene Substances 0.000 claims abstract description 18
- 229920002223 polystyrene Polymers 0.000 claims abstract description 18
- 239000002904 solvent Substances 0.000 claims abstract description 16
- 238000001816 cooling Methods 0.000 claims abstract description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000002791 soaking Methods 0.000 claims abstract description 9
- 238000007711 solidification Methods 0.000 claims abstract description 5
- 230000008023 solidification Effects 0.000 claims abstract description 5
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 4
- 238000000465 moulding Methods 0.000 claims abstract description 4
- MYRTYDVEIRVNKP-UHFFFAOYSA-N 1,2-Divinylbenzene Chemical compound C=CC1=CC=CC=C1C=C MYRTYDVEIRVNKP-UHFFFAOYSA-N 0.000 claims description 32
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 26
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 claims description 21
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 18
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 18
- 239000000203 mixture Substances 0.000 claims description 18
- KBPLFHHGFOOTCA-UHFFFAOYSA-N 1-Octanol Chemical compound CCCCCCCCO KBPLFHHGFOOTCA-UHFFFAOYSA-N 0.000 claims description 12
- 238000001125 extrusion Methods 0.000 claims description 12
- 239000002202 Polyethylene glycol Substances 0.000 claims description 10
- 229920001223 polyethylene glycol Polymers 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 10
- HHVIBTZHLRERCL-UHFFFAOYSA-N sulfonyldimethane Chemical compound CS(C)(=O)=O HHVIBTZHLRERCL-UHFFFAOYSA-N 0.000 claims description 10
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 9
- 238000005191 phase separation Methods 0.000 claims description 9
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 8
- 238000004090 dissolution Methods 0.000 claims description 7
- ZIBGPFATKBEMQZ-UHFFFAOYSA-N triethylene glycol Chemical compound OCCOCCOCCO ZIBGPFATKBEMQZ-UHFFFAOYSA-N 0.000 claims description 7
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 claims description 6
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims description 6
- 229920002292 Nylon 6 Polymers 0.000 claims description 6
- 229920002302 Nylon 6,6 Polymers 0.000 claims description 6
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 6
- 229920000223 polyglycerol Polymers 0.000 claims description 5
- 229920006152 PA1010 Polymers 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 4
- 229940068886 polyethylene glycol 300 Drugs 0.000 claims description 4
- 229940057847 polyethylene glycol 600 Drugs 0.000 claims description 4
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 claims description 4
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 claims description 3
- 229940113115 polyethylene glycol 200 Drugs 0.000 claims description 3
- 229940068918 polyethylene glycol 400 Drugs 0.000 claims description 3
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 claims description 3
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 claims description 2
- XJKSTNDFUHDPQJ-UHFFFAOYSA-N 1,4-diphenylbenzene Chemical group C1=CC=CC=C1C1=CC=C(C=2C=CC=CC=2)C=C1 XJKSTNDFUHDPQJ-UHFFFAOYSA-N 0.000 claims description 2
- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical compound O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 claims description 2
- IGMXPFJCHAFYAZ-UHFFFAOYSA-N prop-1-enyl hydrogen carbonate Chemical compound CC=COC(O)=O IGMXPFJCHAFYAZ-UHFFFAOYSA-N 0.000 claims description 2
- -1 tetramethyl sulfone Chemical class 0.000 claims description 2
- 239000008096 xylene Substances 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 claims 7
- 238000004519 manufacturing process Methods 0.000 claims 2
- 238000000926 separation method Methods 0.000 abstract description 15
- 239000002105 nanoparticle Substances 0.000 abstract description 13
- 230000001105 regulatory effect Effects 0.000 abstract description 8
- 230000008859 change Effects 0.000 abstract description 3
- 230000035699 permeability Effects 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 24
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 21
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 18
- 239000011148 porous material Substances 0.000 description 14
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 10
- 239000003960 organic solvent Substances 0.000 description 9
- 230000004907 flux Effects 0.000 description 8
- 229920000642 polymer Polymers 0.000 description 8
- 210000001161 mammalian embryo Anatomy 0.000 description 7
- 150000001335 aliphatic alkanes Chemical class 0.000 description 6
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 5
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 5
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 230000001276 controlling effect Effects 0.000 description 4
- 230000003993 interaction Effects 0.000 description 4
- 238000005265 energy consumption Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
- WNORZIRJJLYFFF-UHFFFAOYSA-N 2-methylcyclopropan-1-one Chemical class CC1CC1=O WNORZIRJJLYFFF-UHFFFAOYSA-N 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000011978 dissolution method Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000007720 emulsion polymerization reaction Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 239000010954 inorganic particle Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000005371 permeation separation Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- LYXOWKPVTCPORE-UHFFFAOYSA-N phenyl-(4-phenylphenyl)methanone Chemical compound C=1C=C(C=2C=CC=CC=2)C=CC=1C(=O)C1=CC=CC=C1 LYXOWKPVTCPORE-UHFFFAOYSA-N 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/08—Hollow fibre membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0009—Organic membrane manufacture by phase separation, sol-gel transition, evaporation or solvent quenching
- B01D67/0011—Casting solutions therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0088—Physical treatment with compounds, e.g. swelling, coating or impregnation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/08—Hollow fibre membranes
- B01D69/085—Details relating to the spinneret
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/56—Polyamides, e.g. polyester-amides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/30—Chemical resistance
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Chemistry (AREA)
- Dispersion Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Artificial Filaments (AREA)
Abstract
A method for preparing a polyamide hollow fiber membrane by thermally induced phase separation belongs to the technical field of membranes. Comprising the following steps: 1) Dissolving 20-40 parts of polyamide in 40-70 parts of diluent at 200-250 ℃, adding 10-20 parts of pore-forming particles after dissolving, continuously dissolving, and carrying out online defoaming to obtain a casting solution; 2) Extruding the casting solution and the core solution into hollow fiber membrane blanks, passing through an air bath section, and then, entering a cooling bath for solidification and molding to obtain hollow fiber membrane filaments; 3) And (3) placing the hollow fiber membrane filaments in water for cleaning, then placing the hollow fiber membrane filaments in an extracting agent for cleaning out the diluting agent, finally soaking the hollow fiber membrane filaments in a solvent for cleaning out the pore-forming particles, and cleaning and airing the hollow fiber membrane filaments to obtain the polyamide hollow fiber membrane. According to the method for preparing the polyamide hollow fiber membrane by thermally induced phase separation, the polystyrene nano particles are added to regulate and control the porosity of polyamide, so that the membrane has high permeability; the phase change rate of the inner surface and the outer surface of the membrane is precisely regulated, so that the membrane has good separation precision.
Description
Technical Field
The invention belongs to the technical field of membranes, and particularly relates to a method for preparing a polyamide hollow fiber membrane by thermally induced phase separation.
Background
The petrochemical and pharmaceutical industries are one of the prop industries of the national economy. In these industries, the processes of separation and purification of materials, purification and refining of drugs, recovery of solvents, etc. mainly employ traditional methods of distillation, rectification, crystallization, etc., which have large energy consumption and high cost, and generally account for 40-70% of the total investment and energy consumption cost (Nature, 532 (2016) 435-437; nature. Mater., 16 (2017) 276-279). The membrane separation technology is a novel technology, does not involve phase change, can utilize simple physical screening to separate substances with high precision, and has great contribution to water resource recycling and sea water desalination. The membrane separation technology is applied to the material separation and purification of an organic solvent system, so that the energy consumption is reduced, and the sustainable development is realized. However, unlike aqueous applications, in organic solvents, membrane materials are required to have robust solvent resistance in addition to high permeation separation characteristics. Polyamide (PA) is a polymer material with excellent properties, which has the characteristics of high toughness, high strength, low friction coefficient, excellent impact resistance, good chemical stability (seawater, solvent, oil resistance) and the like. However, due to the high heat and solvent resistance of the polymers, the polymers have certain difficulties in solution forming and film forming, and all polyamide films are prepared by melt injection molding at present. However, the film stretched after melt extrusion has the problem of low separation precision, and cannot be applied to high-precision separation in the petroleum and chemical industries and the pharmaceutical industry at present.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to design and provide a technical scheme of a method for preparing a polyamide hollow fiber membrane by thermally induced phase separation, and the porosity of polyamide is regulated and controlled by adding polystyrene nano particles with adjustable pore diameters, which can be dissolved in a later period, so that the membrane has high permeability; further, the phase change rate of the inner surface and the outer surface of the membrane is precisely regulated so as to obtain a separation cortex with high separation precision, so that the membrane has good separation precision, and the efficient separation application of the membrane in an organic solvent system is realized.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized by comprising the following steps of:
1) Dissolving 20-40 parts of polyamide in 40-70 parts of diluent at 200-250 ℃, adding 10-20 parts of pore-forming particles after the polyamide is uniformly dissolved, continuously dissolving, and carrying out online defoaming to obtain a casting solution; the diluent is at least one of dimethyl sulfone, sulfolane, maleic anhydride, 4-phenyl diphenyl ketone, vinyl carbonate, propenyl carbonate, tetramethyl sulfone, polyethylene glycol and polyethylene glycol dimethyl ether; the pore-forming particles are polystyrene particles crosslinked by divinylbenzene;
2) Extruding the casting solution and the core solution into hollow fiber membrane blanks through a spinneret, and allowing the hollow fiber membrane blanks to enter a cooling bath for phase separation and solidification molding after passing through an air bath section to obtain hollow fiber membrane filaments; the cooling bath is one of a mixture of 5-15 parts of polyethylene glycol and 85-95 parts of polyglycerol, a mixture of 15-25 parts of glycerol and 75-85 parts of 1-octanol, and a mixture of 25-35 parts of diethylene glycol and 65-75 parts of triethylene glycol;
3) And (3) placing the obtained hollow fiber membrane filaments in water for cleaning, then placing the hollow fiber membrane filaments in an extracting agent for cleaning out a diluent, finally soaking the hollow fiber membrane filaments in a solvent for cleaning out pore-forming particles, and obtaining the polyamide hollow fiber membrane after cleaning and airing.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized in that in the step 1): the dissolution temperature is 220-230 ℃, the polyamide is 25-35 parts, the diluent is 50-60 parts, and the pore-forming particles are 14-16 parts.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized in that in the step 1): the polyamide is one of polyamide 6, polyamide 66, polyamide 10 and polyamide 1010, and the molecular weight is 1.5-3 ten thousand, preferably 2-2.5 ten thousand.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized in that in the step 1): the pore-forming particles are polystyrene particles crosslinked by divinylbenzene, and the content of the divinylbenzene is 5-15%, preferably 8-12%, of the polystyrene particles; the particle size of the particles is 50-200 nm, preferably 80-150 nm; the dissolution time of the porogenic particles is 20 minutes to 2 hours, preferably 40 minutes to 1.5 hours, more preferably 1 hour to 1.2 hours.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized in that in the step 2): the diameter of the inner hole of the spinneret is 0.8-1.2 mm, the extrusion diameter of the polyamide feed liquid is 1.6-2.0 mm, and the size of the slit is controlled to be not less than 0.4 mm.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized in that in the step 2): the extrusion core liquid is at least one of polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400 and polyethylene glycol 600.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized in that in the step 2): the cooling bath is one of a mixture of 10 parts of polyethylene glycol and 90 parts of polyglycerol, a mixture of 20 parts of glycerol and 80 parts of 1-octanol, and a mixture of 30 parts of diethylene glycol and 70 parts of triethylene glycol; the temperature of the cooling bath is-10 to 10 ℃, preferably-5 to 5 ℃, more preferably-2 to 2 ℃.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized in that in the step 2): the length of the air bath section is 2-20 cm, preferably 5-15 cm, more preferably 8-10 cm.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized by comprising the following steps of: the extractant is at least one of ethanol, ethyl acetate and methanol at 50-60 ℃ and the temperature is preferably 54-56 ℃.
The method for preparing the polyamide hollow fiber membrane by thermally induced phase separation is characterized by comprising the following steps of: the pore-forming particle cleaning solvent is at least one of toluene, xylene, chloroform, styrene, carbon tetrachloride and methyl ethyl ketone.
The method for preparing the polyamide hollow fiber membrane by using the thermal phase separation method provided by the invention solves the problem of dissolution by selecting a proper diluent to dissolve polyamide at high temperature to obtain the membrane casting solution, so that the membrane casting solution has membrane forming performance. The polymers, additives, solvents and diluents used in the present invention are all preferably selected according to Hansen interaction theory, with the important consideration of the compatibility of these materials to prevent defects. In addition, the parameters such as the addition amount, molecular weight, concentration, type, etc. of each component set in the present invention are defined by taking into consideration the thermodynamic stability of the polyamide solution. Thermodynamic stability is a precondition for preparing high-performance hollow fiber membranes.
The invention utilizes the high-temperature dissolution method of the thermally induced phase to dissolve the thermally induced phase into a uniform solution so as to realize extrusion molding. The invention utilizes the divinylbenzene crosslinked polystyrene nano particles to regulate and control the porosity of the polyamide membrane body, solves the problem that the porosity of the polyamide membrane is difficult to clean when the traditional inorganic particles are used for regulating and controlling, and has remarkable innovation. It is known that polyamide materials have excellent solvent resistance and poor acid and alkali resistance. Conventional inorganic nanoparticles, such as silica, titania, calcium carbonate, etc., require inorganic acids to clean them, thereby achieving higher porosity. Therefore, they are difficult to use for controlling the porosity of polyamide membranes. In addition, conventional uncrosslinked organic nanoparticles, such as polystyrene particles prepared by conventional emulsion polymerization, are easily dissolved at high temperature and difficult to exert their porogenic effect. Crosslinked organic nanoparticles, such as crosslinked polyimide particles, are difficult to dissolve, cannot be washed out, and do not achieve sufficient porosity. The invention adopts divinylbenzene crosslinked polystyrene particles as a pore-forming agent, and the crosslinking bond is broken after being treated for a certain time at high temperature, so that the divinylbenzene crosslinked polystyrene particles can be cleaned by using a solvent, and a rich pore channel structure is obtained. This high temperature treatment time is achieved in the present invention by controlling the dissolution time of the particles in the casting solution. In addition, according to the different amounts of divinylbenzene used, different dissolution times can be regulated and controlled to regulate and control the breaking degree of cross bonds, so that the cleaning effect of the cross bonds is regulated and controlled, the polyamide membrane with high porosity is obtained, and the nano particles are used for regulating and controlling the bulk porosity of the polyamide membrane.
The invention further regulates and controls the pore diameter of the membrane surface by changing the inner cooling bath and the outer cooling bath so as to endow the membrane with high separation precision. The internal and external cooling baths used in the present invention are solutions or solvents that interact strongly with the polyamide but weakly with the diluent. In the process of preparing the hollow fiber membrane by thermally induced phase separation, the regulation and control of the pore canal structure of the cortex is extremely important for realizing the separation precision of the membrane. The pore structure is closely related to the concentration of the polymer on the surface. Under normal conditions, the inner and outer cooling baths adopt a solution or a solvent which has strong interaction with the diluent and weak interaction with the polymer, and the diluent is induced to be enriched on the surface in the forming process so as to reduce the concentration of the polymer on the surface, so that the pore structure of the inner layer of the polymer hollow fiber membrane is in a loose macroporous state and cannot have fine-grade separation characteristics. According to the invention, reverse thinking is applied, and according to the solubility parameter theory, solutions with different interactions with polyamide and diluent are used as inner and outer cooling baths respectively, so that different degrees of enrichment of polymers on the inner and outer surfaces are realized, and the pore structures on the inner and outer surfaces of the polyamide hollow fiber membrane are regulated and controlled, so that high-precision separation of the polyamide hollow fiber membrane is realized.
Detailed Description
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
1) At 200 ℃, 20 parts of polyamide 6 with the molecular weight of 1.6 ten thousand is added into 70 parts of dimethyl sulfone, 10 parts of polystyrene nano particles with the 50 nanometers and the divinylbenzene content of 5 percent are added after the polyamide is uniformly dissolved, the continuous 2 hours are carried out, and then the online defoaming is carried out to obtain the casting solution;
2) Extruding the polyamide 6 casting solution and polyethylene glycol 200 obtained by using a spinneret with an inner hole diameter of 0.8 mm, an extrusion diameter of 1.6 mm and a slit size of 0.4 mm into a hollow fiber membrane embryo, introducing the hollow fiber membrane embryo into a mixture of 10% polyethylene glycol and 90% polyglycerol at-10 ℃ through an air section of 2 cm, and carrying out induced phase separation and solidification molding to obtain the hollow fiber membrane filament;
3) And (3) placing the obtained polyamide hollow fiber membrane filaments in water for cleaning, then placing the polyamide hollow fiber membrane filaments in ethanol at 60 ℃ for cleaning out the diluent, finally soaking the polyamide hollow fiber membrane filaments in toluene for cleaning pore-forming particles, and obtaining a polyamide hollow fiber membrane product after cleaning and airing.
Example 2
1) At 250 ℃, 40 parts of polyamide 66 with the molecular weight of 3 ten thousand is added into 40 parts of 4-phenylbenzophenone, 20 parts of polystyrene nano particles with the content of 200 nanometers and 15 percent of divinylbenzene are added after the polyamide is uniformly dissolved, the continuous 20 minutes are carried out, and then the online defoaming is carried out to obtain casting solution;
2) Extruding the polyamide 66 casting solution and polyethylene glycol 600 into a hollow fiber membrane blank by using a spinneret with an inner hole diameter of 1.2 mm, an extrusion diameter of 2.0 mm and a slit size of 0.4 mm, and introducing the hollow fiber membrane blank into a mixture of 30% diethylene glycol and 70% triethylene glycol at 10 ℃ through an air section of 10 cm to induce phase separation and solidify and form to obtain the hollow fiber membrane yarn;
3) And (3) placing the obtained polyamide hollow fiber membrane filaments in water for cleaning, then placing the polyamide hollow fiber membrane filaments in ethyl acetate at 50 ℃ for cleaning out the diluent, finally soaking the polyamide hollow fiber membrane filaments in styrene for cleaning pore-forming particles, and obtaining a polyamide hollow fiber membrane product after cleaning and airing.
Example 3
1) At 230 ℃, 30 parts of polyamide 55 with the molecular weight of 2.5 ten thousand is added into 55 parts of tetramethylsulfone, 15 parts of polystyrene nano particles with the content of 100 nanometers and 10 percent of divinylbenzene are added after the polyamide 10 is uniformly dissolved, the continuous operation is carried out for 1 hour, and then the online defoaming is carried out to obtain casting solution;
2) Extruding the obtained polyamide 10 casting solution and polyethylene glycol 400 into a hollow fiber membrane embryo by using a spinneret with an inner hole diameter of 0.8 mm, an extrusion diameter of 1.8 mm and a slit size of 0.5 mm, and introducing the hollow fiber membrane embryo into a mixture of 20% glycerol and 80% 1-octanol at 0 ℃ through an air section of 20 cm to induce phase separation and solidify and form the hollow fiber membrane embryo, thereby obtaining the hollow fiber membrane silk;
3) And (3) placing the obtained polyamide hollow fiber membrane filaments in water for cleaning, then placing the polyamide hollow fiber membrane filaments in methanol at 55 ℃ for cleaning out a diluent, finally soaking the polyamide hollow fiber membrane filaments in chloroform for cleaning pore-forming particles, and obtaining a polyamide hollow fiber membrane product after cleaning and airing.
Example 4
1) At 215 ℃, 25 parts of polyamide 1010 with the molecular weight of 2 ten thousand is added into 67 parts of polyethylene glycol dimethyl ether, after the polyamide is uniformly dissolved, 8 parts of polystyrene nano particles with the 80 nanometer content and the divinylbenzene content of 8 percent are added, the continuous operation is carried out for 1.5 hours, and then the online defoaming is carried out to obtain casting solution;
2) Extruding the obtained polyamide 1010 casting solution and polyethylene glycol 600 into a hollow fiber membrane embryo by using a spinneret with an inner hole diameter of 1.0 mm, an extrusion diameter of 2.0 mm and a slit size of 0.5 mm, introducing into a mixture of 30% diethylene glycol and 70% triethylene glycol at 5 ℃ through an air section of 10 cm, and carrying out induced phase separation and solidification forming to obtain the hollow fiber membrane silk;
3) And (3) placing the obtained polyamide hollow fiber membrane filaments in water for cleaning, then placing the polyamide hollow fiber membrane filaments in ethanol at 60 ℃ for cleaning out the diluent, finally soaking the polyamide hollow fiber membrane filaments in dimethylbenzene for cleaning pore-forming particles, and obtaining a polyamide hollow fiber membrane product after cleaning and airing.
Example 5
1) At 20 ℃, 20 parts of polyamide 6 with the molecular weight of 3 ten thousand is added into 60 parts of dimethyl sulfone, after the polyamide is uniformly dissolved, 20 parts of polystyrene nano particles with the content of 200 nanometers and 15 percent of divinylbenzene are added, the continuous operation is carried out for 2 hours, and then the online defoaming is carried out to obtain casting solution;
2) Extruding the polyamide 6 casting solution and polyethylene glycol 300 into a hollow fiber membrane blank by using a spinneret with an inner hole diameter of 0.8 mm, an extrusion diameter of 2.0 mm and a slit size of 0.6 mm, and introducing the hollow fiber membrane blank into a mixture of 30% diethylene glycol and 70% triethylene glycol at 10 ℃ through an air section of 10 cm to induce phase separation and solidify and form to obtain the hollow fiber membrane yarn;
3) And (3) placing the obtained polyamide hollow fiber membrane filaments in water for cleaning, then placing the polyamide hollow fiber membrane filaments in methanol at 50 ℃ for cleaning out the diluent, finally soaking the polyamide hollow fiber membrane filaments in dimethylbenzene for cleaning pore-forming particles, and obtaining a polyamide hollow fiber membrane product after cleaning and airing.
Example 6
1) At 250 ℃, 40 parts of polyamide 66 with the molecular weight of 3 ten thousand is added into 40 parts of mixed diluent of dimethyl sulfone and sulfolane, 20 parts of polystyrene nano particles with the 50-nanometer divinylbenzene content of 10% are added after the polyamide is uniformly dissolved, the continuous operation is carried out for 20 hours, and then the online defoaming is carried out to obtain casting solution;
2) Extruding the polyamide 66 casting solution and polyethylene glycol 300 into hollow fiber membrane embryo by using a spinneret with an inner hole diameter of 0.8 mm, an extrusion diameter of 1.6 mm and a slit size of 0.4 mm, introducing into a mixture of 20% glycerol and 80% 1-octanol at-5 ℃ through an air section of 2 cm, inducing phase separation, and solidifying and forming to obtain the hollow fiber membrane silk;
3) And (3) placing the obtained polyamide hollow fiber membrane filaments in water for cleaning, then placing the polyamide hollow fiber membrane filaments in ethanol at 60 ℃ for cleaning out the diluent, finally soaking the polyamide hollow fiber membrane filaments in styrene for cleaning pore-forming particles, and obtaining a polyamide hollow fiber membrane product after cleaning and airing.
The beneficial effects of the invention are further demonstrated by corresponding test data below. Tables 1-3 are tables for detecting the properties of the polyamide hollow fiber membranes prepared in the examples of the present invention.
TABLE 1 Performance of Polyamide hollow fiber membranes as an index of example 1
| Polyamide hollow fiber membrane | Index (I) |
| Interception aperture | 30-60 nm |
| Ethanol flux | 600 LMH@bar |
| Porosity of the porous material | 60-80% |
| Organic solvent resistance | Ethanol, dimethylformamide, N-methylpyrrolidone, methanol, acetone, acetonitrile, alkane and the like |
| Tensile Strength | 8 N |
| Elongation at break | 200% |
TABLE 2 Properties of Polyamide hollow fiber membranes as an index of example 2
| Polyamide hollow fiber membrane | Index (I) |
| Interception aperture | 100-200 nm |
| Porosity of the porous material | 50-60% |
| Acetonitrile flux | 1500 LMH@bar |
| Organic solvent resistance | Ethanol, dimethyl sulfoxide, and propyleneKetones, acetonitrile, alkanes, and the like |
| Tensile Strength | 13 N |
| Elongation at break | 220% |
TABLE 3 Properties of Polyamide hollow fiber membranes as an index of example 3
| Polyamide hollow fiber membrane | Index (I) |
| Interception aperture | 80-120 nm |
| Porosity of the porous material | 55-65% |
| Acetone flux | 900 LMH@bar |
| Organic solvent resistance | Ethanol, dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, acetonitrile, alkane, etc |
| Tensile Strength | 10 N |
| Elongation at break | 190% |
TABLE 4 Properties of Polyamide hollow fiber membranes for the index of EXAMPLE 4
| Polyamide hollow fiber membrane | Index (I) |
| Interception aperture | 60-100 nanometers |
| Porosity of the porous material | 65-75% |
| Dimethylformamide flux | 700 LMH@bar |
| Organic solvent resistance | Ethanol, dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, acetonitrile, alkane, etc |
| Tensile Strength | 9 N |
| Elongation at break | 200% |
TABLE 5 Performance of Polyamide hollow fiber membranes of the index of EXAMPLE 5
| Polyamide hollow fiber membrane | Index (I) |
| Interception aperture | 100-200 nm |
| Porosity of the porous material | 70-80% |
| Dimethylacetamide flux | 800 LMH@bar |
| Organic solvent resistance | Ethanol, dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, acetonitrile, alkane, etc |
| Tensile Strength | 8.2 N |
| Elongation at break | 205% |
TABLE 6 Performance of Polyamide hollow fiber membranes of the index of EXAMPLE 6
| Polyamide hollow fiber membrane | Index (I) |
| Interception aperture | 40-80 nm |
| Porosity of the porous material | 60-70% |
| Methanol flux | 800 LMH@bar |
| Organic solvent resistance | Ethanol, dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, acetonitrile, alkane, etc |
| Tensile Strength | 11 N |
| Elongation at break | 210% |
Tables 1-3 show that: by measuring the solvent permeation flux, selectivity and tensile strength of the polyamide hollow fiber membranes, the comprehensive properties of the hollow fiber membranes prepared in examples 1, 2 and 6 of the invention are excellent, wherein the solvent permeation flux of example 2 optimally reaches 1500LMH@bar; the best pore size for retention performance for example 1 was between 30 and 60 nanometers. The polyamide hollow fiber membranes produced in examples 3 to 5 of the present invention also have the properties described in the present invention.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. A method for preparing a polyamide hollow fiber membrane by thermally induced phase separation, which is characterized by comprising the following steps:
1) Dissolving 20-40 parts of polyamide in 40-70 parts of diluent at 200-250 ℃, adding 10-20 parts of pore-forming particles after the polyamide is uniformly dissolved, continuously dissolving, and carrying out online defoaming to obtain a casting solution; the diluent is at least one of dimethyl sulfone, sulfolane, maleic anhydride, 4-phenyl diphenyl ketone, vinyl carbonate, propenyl carbonate, tetramethyl sulfone, polyethylene glycol and polyethylene glycol dimethyl ether; the pore-forming particles are polystyrene particles crosslinked by divinylbenzene;
2) Extruding the casting solution and the core solution into hollow fiber membrane blanks through a spinneret, and allowing the hollow fiber membrane blanks to enter a cooling bath for phase separation and solidification molding after passing through an air bath section to obtain hollow fiber membrane filaments; the cooling bath is one of a mixture of 5-15 parts of polyethylene glycol and 85-95 parts of polyglycerol, a mixture of 15-25 parts of glycerol and 75-85 parts of 1-octanol, and a mixture of 25-35 parts of diethylene glycol and 65-75 parts of triethylene glycol;
3) And (3) placing the obtained hollow fiber membrane filaments in water for cleaning, then placing the hollow fiber membrane filaments in an extracting agent for cleaning out a diluent, finally soaking the hollow fiber membrane filaments in a solvent for cleaning out pore-forming particles, and obtaining the polyamide hollow fiber membrane after cleaning and airing.
2. A process for the preparation of a polyamide hollow-fiber membrane by thermally induced phase separation as claimed in claim 1, characterized in that in step 1): the dissolution temperature is 220-230 ℃, the polyamide is 25-35 parts, the diluent is 50-60 parts, and the pore-forming particles are 14-16 parts.
3. A process for the preparation of a polyamide hollow-fiber membrane by thermally induced phase separation as claimed in claim 1, characterized in that in step 1): the polyamide is one of polyamide 6, polyamide 66, polyamide 10 and polyamide 1010, and the molecular weight is 1.5-3 ten thousand, preferably 2-2.5 ten thousand.
4. A process for the preparation of a polyamide hollow-fiber membrane by thermally induced phase separation as claimed in claim 1, characterized in that in step 1): the pore-forming particles are polystyrene particles crosslinked by divinylbenzene, and the content of the divinylbenzene is 5-15%, preferably 8-12%, of the polystyrene particles; the particle size of the particles is 50-200 nm, preferably 80-150 nm; the dissolution time of the porogenic particles is 20 minutes to 2 hours, preferably 40 minutes to 1.5 hours, more preferably 1 hour to 1.2 hours.
5. A process for the preparation of a polyamide hollow-fiber membrane by thermally induced phase separation as claimed in claim 1, characterized in that in step 2): the diameter of the inner hole of the spinneret is 0.8-1.2 mm, the extrusion diameter of the polyamide feed liquid is 1.6-2.0 mm, and the size of the slit is controlled to be not less than 0.4 mm.
6. A process for the preparation of a polyamide hollow-fiber membrane by thermally induced phase separation as claimed in claim 1, characterized in that in step 2): the extrusion core liquid is at least one of polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400 and polyethylene glycol 600.
7. A process for the preparation of a polyamide hollow-fiber membrane by thermally induced phase separation as claimed in claim 1, characterized in that in step 2): the cooling bath is one of a mixture of 10 parts of polyethylene glycol and 90 parts of polyglycerol, a mixture of 20 parts of glycerol and 80 parts of 1-octanol, and a mixture of 30 parts of diethylene glycol and 70 parts of triethylene glycol; the temperature of the cooling bath is-10 to 10 ℃, preferably-5 to 5 ℃, more preferably-2 to 2 ℃.
8. A process for the preparation of a polyamide hollow-fiber membrane by thermally induced phase separation as claimed in claim 1, characterized in that in step 2): the length of the air bath section is 2-20 cm, preferably 5-15 cm, more preferably 8-10 cm.
9. A process for preparing a polyamide hollow-fiber membrane by thermally induced phase separation as claimed in claim 1, characterized in that in step 3): the extractant is at least one of ethanol, ethyl acetate and methanol at 50-60 ℃ and the temperature is preferably 54-56 ℃.
10. A process for preparing a polyamide hollow-fiber membrane by thermally induced phase separation as claimed in claim 1, characterized in that in step 3): the pore-forming particle cleaning solvent is at least one of toluene, xylene, chloroform, styrene, carbon tetrachloride and methyl ethyl ketone.
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| US20060102556A1 (en) * | 2002-07-13 | 2006-05-18 | Piletsky Sergey A | Porous molecularly imprinted polymer membranes |
| CN102500246A (en) * | 2011-11-23 | 2012-06-20 | 浙江大学 | Method for preparing reinforced hollow fiber membrane of braided tube by using low-temperature thermal-induced phase separation method |
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