Hydrophilic polyphenylene sulfide polyamide microporous membrane and preparation method thereof

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to a hydrophilic polyphenylene sulfide polyamide microporous membrane and a preparation method thereof. Polyamide and a polyphenylene sulfide synthesis raw material containing a polar group are subjected to a polymerization reaction together, after the obtained polyphenylene sulfide polyamide resin is prepared into a membrane, polyamide in the membrane material is partially etched, and the polyphenylene sulfide polyamide microporous membrane with excellent hydrophilicity is obtained. The prepared polyphenylene sulfide polyamide microporous membrane has a polyphenylene sulfide membrane skeleton and has the characteristics of corrosion resistance, high temperature resistance, good rigidity and high strength, the peripheries of pores are mainly made of polyamide, the polyphenylene sulfide polyamide microporous membrane has the characteristics of high hydrophilicity, good self-lubricating property and the like, the pore size and porosity can be controlled through the preparation process, and the preparation process is simple. And ion transportation or gas separation and the like in an electrolyte environment can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a hydrophilic polyphenylene sulfide polyamide microporous membrane and a preparation method thereof. Background Art

[0002] Polyphenylene sulfide resin ( ) has excellent high temperature resistance, corrosion resistance, radiation resistance, flame retardancy, balanced physical and mechanical properties, excellent dimensional stability, and excellent electrical properties, and is widely used as a structural polymer material. As a porous membrane, polyphenylene sulfide membrane is a functional material with excellent performance, widely used in separation, filtration, catalysis, sensing and other fields. However, its structure determines that it has a high degree of inertness and poor compatibility with polar solvents or polar environments. Its hydrophilic angle generally exceeds 100°, and its hydrophobicity is obvious. There is a great resistance to the transport of highly hydrophilic and ionic substances, such as the accumulation of ions on the surface and slow passage speed. Its hydrophilicity can be improved through structural modification. For example, sulfonation can greatly improve its hydrophilicity by making its side chain carry sulfonic acid groups. However, the degree of sulfonation needs to be above 50%, which directly affects its strength and thermal properties. Introducing carboxyl and hydroxyl groups on its side through copolymerization can improve its hydrophilicity, but the content is difficult to reach 30% or above, and it is difficult to reduce the hydrophilic angle to below 30°. Adding fillers such as zirconium dioxide can effectively improve its hydrophilicity. However, the amount of mixed fillers required is large, which affects the flexibility of polyphenylene sulfide and makes it difficult to form a film. Its bonding strength is insufficient when sprayed on the film surface.

[0003] Polyamide, also known as nylon, offers high mechanical strength, a high softening point, heat resistance, low friction coefficient, and wear resistance. It is self-lubricating, shock-absorbing, and sound-absorbing. It is also resistant to oils, weak acids, alkalis, and common solvents. It has excellent electrical insulation and is self-extinguishing. It is non-toxic, odorless, and weather-resistant, but has poor dyeability. However, its disadvantage is high water absorption, which affects dimensional stability and electrical properties. Extensive research has been conducted using polyphenylene sulfide and polyamide to create polymer alloys that combine the excellent properties of both for engineering applications. However, polymer alloys often have a high ratio of both polymers, such as 40:60 or 20:80. The ratio must be adjusted according to the application. Furthermore, polymer alloys blended using a twin-screw extruder suffer from poor homogeneity and interfacial compatibility, making them unsuitable for film applications. Films, in particular, need to withstand high corrosion, high temperatures, high salt concentrations, and ionic environments in electrolytes. Polyamides, due to their high water absorption and poor corrosion resistance, do not meet these requirements. On the other hand, for ion transport and gas passage in an electrolyte environment, the film must be able to maintain strength and dimensional stability in this corrosive and high-temperature environment. Pore size and porosity are also basic performance requirements. For example, they must allow the passage of smaller ions and molecules, such as water molecules, protons, oxygen molecules, and hydrogen molecules, while being able to intercept larger ions and molecules, such as catalyst particles. At the same time, they must be able to pass the required amount of molecules and ions per unit area per unit time, achieving a certain level of ion and molecule transport efficiency.

[0004] Therefore, the art needs to develop new strategies to obtain materials that have the excellent properties of both polyphenylene sulfide and polyamide. Summary of the Invention

[0005] In order to achieve the above requirements, the present invention provides a method for preparing a hydrophilic polyphenylene sulfide polyamide microporous membrane, which comprises the following steps:

[0006] (1) Using sulfur-containing monomers, dihalogen aromatic compounds and polar dihalogen aromatic compounds as synthetic raw materials for polyphenylene sulfide, polymerizing them together with polyamide in a polar aprotic solvent under the protection of inert gas, recovering the solvent, and washing, purifying and drying the reaction product to obtain polyphenylene sulfide polyamide resin;

[0007] (2) Extruding and granulating the dried polyphenylene sulfide polyamide resin through a twin-screw extruder to form a masterbatch for cast film;

[0008] (3) the masterbatch obtained in the drying step (2) is subjected to a film casting method, and uniaxial stretching or biaxial stretching is performed to increase the crystallinity to obtain a polyphenylene sulfide polyamide cast film;

[0009] (4) The polyphenylene sulfide polyamide cast film obtained in step (3) is subjected to steam etching to dissolve a portion of the polyamide to obtain a hydrophilic polyphenylene sulfide polyamide microporous membrane.

[0010] Furthermore, the dihalogen aromatic compound is at least one selected from 1,4-dihalobenzene, 2,4-dihalobenzene, 3,5-dihalobenzene, 4,4'-dihalobiphenyl, 4,4'-dihalodiphenyl sulfone, 4,4'-dihalobenzophenone or 4,4'-dihalodiphenyl ether.

[0011] Preferably, the dihalogen aromatic compound is 1,4-dihalobenzene, also known as p-dihalobenzene.

[0012] Furthermore, the polar dihalogen aromatic compound has a polar functional group selected from hydroxyl, amino, carboxyl, sulfonic acid, sulfonyl chloride and combinations thereof.

[0013] Furthermore, the polar dihalogen aromatic compound is selected from at least one of the following:

[0014] 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 , wherein X is a halogen atom, and Z, Z1 and Z2 are each independently a hydroxyl group, an amino group, a carboxyl group, a sulfonic acid group or a sulfonyl chloride group.

[0015] Furthermore, the molar ratio of the polar dihalogen aromatic compound to the dihalogen aromatic compound is 2.5-10.0:97.5-90.0.

[0016] Furthermore, the sulfur-containing monomer is selected from at least one of sodium sulfide, hydrogen sulfide, sodium hydrosulfide or sulfur.

[0017] Furthermore, in the polymerization reaction system, the molar ratio of divalent sulfide ions to the total amount of dihalogen aromatic compounds and polar dihalogen aromatic compounds is 0.95-1.05:1.0.

[0018] Furthermore, the polyamide includes A-type polyamide or AB-type polyamide.

[0019] Furthermore, the structure of the type A polyamide is shown in formula (I):

[0020] (I)

[0021] Where m=4-12.

[0022] Furthermore, the structure of the AB type polyamide is shown in formula (II):

[0023] (II)

[0024] Where m1 and m2 = 4-12.

[0025] Furthermore, the polyamide is selected from at least one of PA6, PA46, PA66 and PA1010.

[0026] Furthermore, the mass ratio of the amount of polyamide used to the theoretical synthesis amount of polyphenylene sulfide is 20-50:80-50.

[0027] As used herein, the theoretical synthesis amount of polyphenylene sulfide refers to the theoretical maximum amount of polyphenylene sulfide that can be synthesized based on the added amounts of the synthetic raw materials of polyphenylene sulfide (ie, sulfur-containing monomers, dihalogen aromatic compounds, and polar dihalogen aromatic compounds).

[0028] Furthermore, the added polyamide is in the form of a masterbatch with a diameter of less than 3 mm after granulation or small particles with a particle size of less than 3 mm before granulation.

[0029] As used herein, the inert gas is broadly defined as any gas that does not chemically react with the polyphenylene sulfide synthesis raw materials and polyamide used in the present invention, which may include, for example, nitrogen, argon, helium, etc.

[0030] Furthermore, the polar aprotic solvent is selected from sulfone or sulfone compounds, amine compounds or lactam compounds.

[0031] Furthermore, the polar aprotic solvent is selected from at least one of N-methyl-2-pyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone, 1,3-dimethyl-2-imidazolone, hexamethylphosphoramide, N,N-dimethylacetamide, N,N-dimethylamide, caprolactam, N-ethylcaprolactam, N,N-vinylpyrrolidone, 1,3-dimethyl-2-imidazolidinone lactam, tetramethylurea, dimethyl sulfoxide and sulfolane.

[0032] Furthermore, the amount of the polar aprotic solvent is: per mole of theoretical synthesis amount of polyphenylene sulfide, the amount of solvent is 0.5-1.0 L.

[0033] Furthermore, the step (1) comprises: firstly subjecting the sulfur-containing monomer to a dehydration reaction in a polar aprotic solvent under the protection of an inert gas; then adding a dihalogen aromatic compound and a polar dihalogen aromatic compound and subsequently adding polyamide, and then conducting a polymerization reaction.

[0034] Furthermore, the temperature of the dehydration reaction is controlled at 175-205° C., and after the dehydration is completed, the temperature is reduced to below 150° C. before adding other materials.

[0035] Furthermore, depending on the sulfur-containing monomer used, a base may be optionally added during the dehydration reaction. Those skilled in the art will appreciate that when, for example, sodium hydrosulfide is used as the sulfur-containing monomer, the addition of a base may neutralize the hydrogen sulfide gas generated during the dehydration process.

[0036] Furthermore, the base comprises sodium hydroxide.

[0037] Furthermore, the polymerization reaction temperature is 200-300° C., and the reaction time is 3-12 hours.

[0038] Furthermore, the polymerization reaction comprises first reacting at 200-250° C., preferably 220-235° C., for 2-6 hours, and then reacting at 235-300° C., preferably 245-255° C., for 3-6 hours.

[0039] Furthermore, stirring is maintained during the polymerization reaction, and the stirring speed is maintained at 80-220 r / min.

[0040] Furthermore, the washing purification comprises washing the reaction product with deionized water, xylene and anhydrous ethanol in sequence.

[0041] Furthermore, the extrusion temperature of the extrusion granulation in step (2) is 285-325° C., the screw speed is between 100-300 rpm, and the plasticizing time is maintained between 1-5 minutes.

[0042] Furthermore, in the process of forming the film by the casting method described in step (3), a casting machine is used to draw the film, and the temperatures of the first to fourth sections of the screw are 185-195°C, 295-305°C, 305-315°C and 2305-315°C, the temperature of the film receiving roller is 35-95°C, the rotation speed is 10-200 mm / min, and the corresponding cast film thickness is 20-200 μm and the cast film width is 50-150 cm;

[0043] Furthermore, the stretching temperature of the uniaxial stretching is 85-15° C., the stretching ratio is 2, 3, 4, 5 and 6 times, the stretching speed is 10-100 mm / min, and the thickness of the film after uniaxial stretching is 2-100 μm.

[0044] Furthermore, the stretching ratio of the biaxial stretching is 1*1, 1*2, 1*4, 2*2, 3*2 and 4*4, the stretching temperature is 80-150°C, preferably 90-130°C, the stretching speed is 5-80 mm / min, and the film thickness after biaxial stretching is 2-100 μm.

[0045] Furthermore, the steam etching in step (4) includes treating the polyphenylene sulfide polyamide cast film in an atmosphere of nitrogen, carbon dioxide or hydrogen in the vapor of formic acid, phenol or cresol at 100-200° C. and 0.08-0.15 MPa for 0.5-6 hours to obtain a hydrophilic polyphenylene sulfide polyamide microporous membrane with a pore size of 0.05-10.0 μm.

[0046] As used herein, drying refers to vacuum drying unless expressly stated otherwise.

[0047] In other aspects, the present invention also provides a hydrophilic polyphenylene sulfide polyamide microporous membrane prepared by the preparation method described herein.

[0048] Beneficial effects of the present invention

[0049] The present invention polymerizes polyamide and a polyphenylene sulfide synthetic raw material containing polar groups, forms a polyphenylene sulfide polyamide resin into a membrane, and then partially etches the polyamide in the membrane material to obtain a polyphenylene sulfide polyamide microporous membrane with excellent hydrophilicity. The polyphenylene sulfide polyamide microporous membrane prepared by the present invention realizes that polyphenylene sulfide is used as the membrane skeleton and polyamide is used as the membrane boundary, that is, polyamide is mainly used around the pores, and polyphenylene sulfide is mainly used in the area away from the pores. Polyphenylene sulfide and polyamide have a stable interface bond, and its structural schematic diagram is shown as follows: Figure 1 The polyphenylene sulfide polyamide microporous membrane prepared by the present invention has a polyphenylene sulfide film skeleton, which is corrosion-resistant, high-temperature resistant, rigid, and high-strength. The pores are mainly composed of polyamide, which has high hydrophilicity and good self-lubrication. The pore size and porosity can be controlled during the preparation process, and can meet the needs of ion transport or gas separation in electrolyte environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The schematic diagram shows the structure of the hydrophilic polyphenylene sulfide polyamide microporous membrane prepared by the present invention. DETAILED DESCRIPTION

[0051] The structure of the polyphenylene sulfide polyamide microporous membrane material provided by the present invention can be schematically represented by formula (III):

[0052] (III),

[0053] The polyamide is an AB type polyamide, such as a polyamide polymerized from hexamethylenediamine and diacid; m1, m2 = 4-12, such as PA46, PA66, PA1010, etc.; m ≥ 9; Z is a group that can electronically coordinate with a carbonyl group or an amino group in the polyamide, such as OH.

[0054] Or formula (IV):

[0055] (IV)

[0056] The polyamide is type A polyamide, such as a polyamide polymerized from lactam or amino acid; wherein m in the polyamide portion is 4-12, m in the polyphenylene sulfide portion is ≥9, and Z is a group capable of electronically coordinating with a carbonyl group or an amino group in the polyamide, such as OH.

[0057] The amino acids used to synthesize polyamide A are all straight-chain amino acids, including: γ-aminobutyric acid ( 4-aminobutyric acid), δ-aminovaleric acid ( 5-aminovaleric acid), ε-aminocaproic acid ( 6-aminohexanoic acid), ζ-aminoheptanoic acid ( 7-aminoheptanoic acid), η-aminooctanoic acid ( 8-aminooctanoic acid), θ-aminononanoic acid (9-aminononanoic acid ), ι-aminodecanoic acid ( 10-aminodecanoic acid), κ-aminoundecanoic acid ( 11-aminoundecanoic acid) or λ-aminododecanoic acid (12-aminododecanoic acid ).

[0058] The polyphenylene sulfide polyamide microporous film of the present invention is prepared by the following technical process: under the protection of an inert gas, dihalogen aromatic compounds, polar dihalogen aromatic compounds, sulfides, etc. are used as polyphenylene sulfide synthesis monomers, and polyamide is used as another polymerization component, and heating and pressurizing are performed in a polar aprotic solvent to obtain a polyphenylene sulfide polyamide resin. Furthermore, the polyphenylene sulfide polyamide resin is purified to obtain a high-purity resin. Thereafter, the resin is cast to form a film. Furthermore, the cast film is uniaxially or biaxially stretched as needed to obtain a polyphenylene sulfide polyamide film. Finally, the film is steam-etched to dissolve a portion of the polyamide to obtain a microporous polyphenylene sulfide polyamide membrane.

[0059] The first step in the preparation of the polyphenylene sulfide polyamide porous membrane of the present invention is the synthesis of the polyphenylene sulfide polyamide resin. Since polyamide has a strong polarity and contains alternating amide bonds, it cannot form a stable interface with the more inert polyphenylene sulfide units. Therefore, it is necessary to increase the polarity of polyphenylene sulfide during the polymerization process. The present invention selects functional groups with strong polarity to increase the polarity of polyphenylene sulfide, such as hydroxyl, amino, carboxyl, sulfonic acid or sulfonyl chloride groups ( ) etc., form a coordination bond with the amide bond to obtain a polyphenylene sulfide polyamide resin with a relatively stable structure. The present invention selects a dihalogen monomer containing the above functional groups as a polar unit, such as: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 , Z, Z1 and Z2 are each independently a hydroxyl group, an amino group, a carboxyl group, a sulfonic acid group or a sulfonyl chloride group. For example: dihalogen phenol 、 、 , dihalonaphthols 、 、 、 、 、 , dihalogenated polyphenols 、 、 and etc.; or dichloroaromatic acids, such as , , etc.; or dihalogen salicylic acid, such as , 、 etc., or dihalogen monomers containing sulfonic acid groups, such as, 、 、 、 、 、 etc., or containing amino dihalogen monomers, such as 、 、 , where X=F, Cl, Br, I.

[0060] The molar ratio of the polar monomer (ie, polar dihalogen aromatic compound) to the dihalogen aromatic compound (such as p-dihalobenzene) is 2.5-10.0:97.5-90.0.

[0061] The polymerization reaction is shown as follows:

[0062] or: .

[0063] More specifically, when Z is a sulfonyl chloride group or a sulfonic acid group ( 、 ), the polymerization reaction can be schematically represented as follows: ;

[0064] in Formed when in contact with water ;

[0065] Or when Z is a phenol group (-OH), the polymerization reaction is shown as follows: .

[0066] Furthermore, the Z group in the polar monomer can be changed as needed.

[0067] In the polymerization reaction, the ratio of the amount of polyamide (type A, type AB) to the theoretical value of polyphenylene sulfide is (by mass): 20-50:80-50.

[0068] The above preparation process uses a polar aprotic solvent as the polymerization medium. The polar aprotic solvent is selected from sulfones or sulfone compounds, amine compounds, or lactam compounds. Preferably, the polar aprotic solvent is selected from at least one of N-methyl-2-pyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone, 1,3-dimethyl-2-imidazolone, hexamethylphosphoramide, N,N-dimethylacetamide, N,N-dimethylimidazolamide, caprolactam, N-ethylcaprolactam, N,N-vinylpyrrolidone, 1,3-dimethyl-2-imidazolidinone lactam, tetramethylurea, dimethyl sulfoxide, or sulfolane. The solvent dosage is 0.5-1.0 L per mole of polyphenylene sulfide.

[0069] Sulfide ion (S 2-) Sodium sulfide, hydrogen sulfide, sodium hydrosulfide or sulfur is used as the sulfur source. Sodium sulfide with low iron content is used, such as 60% yellow low-iron sodium sulfide (iron content less than 20ppm), 45% crystalline sodium sulfide (iron content less than 10ppm), or hydrogen sulfide (purity greater than 99.5%), or 70% yellow low-iron sodium hydrosulfide (iron content less than 20ppm), or 45% liquid sodium hydrosulfide (iron content less than 10ppm), or sulfur (purity greater than 99.9%) can also be selected. This type of sulfur source raw material is added together with an auxiliary agent to a polar aprotic solvent for reaction and dehydration to form sulfide ions (S 2- The temperature during the dehydration stage is controlled at 175-205°C, preferably 190-202°C, and an inert gas atmosphere is used for dehydration. The molar ratio of sulfide to (polar monomer + p-dihalobenzene) is 0.9-1.05:1.0.

[0070] Furthermore, the dihalogen aromatic compound and the monomer containing the Z polar group are added after the dehydration is completed, and the temperature is lowered to below 150° C. before the addition.

[0071] After the sulfur-containing raw materials and polar aprotic solvent are dehydrated, the polyamide is added after the dihalogen aromatic compound and polar dihalogen aromatic compound. The polyamide is selected in the form of a masterbatch (less than 3mm in diameter) or small granules (less than 3mm in diameter) before granulation, with the latter being preferred.

[0072] After all materials have been added, the polymerization phase begins. The polymerization is divided into two stages. The polymerization conditions are: reaction temperature of 200-300°C, reaction time of 3-12 hours; preferably, the reaction is first carried out at 200-250°C, preferably 220-235°C, for 2-6 hours, and then at 235-300°C, preferably 245-255°C, for 3-6 hours. Stirring is maintained during the polymerization process, and the stirring speed is maintained at 80-220 r / min.

[0073] After polymerization is complete and the temperature drops to 190-200°C, the polymer is transferred to a cooling kettle. Water is then added to lower the temperature to 60-90°C. Stirring is maintained throughout the process at a speed of 60-200 r / min. The material is then subjected to solvent recovery. The reaction product is washed sequentially with deionized water at 60-80°C, for example eight times, soaking for 20-40 minutes each time. Stirring is maintained at 80-220 r / min. After the water washes are complete, the product is washed with xylene, for example twice, soaking in xylene for 20-40 minutes each time. Stirring is maintained at 80-220 r / min. After the xylene washes are complete, the product is washed with anhydrous ethanol, for example twice, soaking in anhydrous ethanol for 20-40 minutes each time. Stirring is maintained at 80-220 r / min. The xylene and ethanol are returned to the recovery system, and the product enters the drying process. The product washed with water, xylene and ethanol in sequence is dried in a vacuum oven at 80-150° C. for 2-24 hours to obtain polyphenylene sulfide polyamide resin.

[0074] The second step of manufacturing the polyphenylene sulfide polyamide porous membrane of the present invention is to extrude and granulate the dried polyphenylene sulfide polyamide resin through a twin-screw extruder to form a masterbatch for cast film. Before extrusion granulation, the product can be dried in a vacuum oven at 120-150°C for 4-8 hours. The extrusion temperature is 285-325°C, the screw speed is between 100-300 rpm, and the plasticizing time is maintained between 1-5 minutes. The extruded material strips are cooled with high-purity deionized water, and the material strips are cut into pellets with a diameter of 2-3 mm and a length of 3-5 mm, and then dried in a vacuum drying oven for 6-12 hours as masterbatch for cast film.

[0075] The third step in the manufacture of the polyphenylene sulfide polyamide porous membrane of the present invention is to prepare a cast membrane by casting the synthesized polyphenylene sulfide polyamide resin masterbatch using a casting method. The obtained polyphenylene sulfide polyamide resin masterbatch is cast using a casting device. Before casting, the polyphenylene sulfide polyamide resin masterbatch can be dried in a vacuum oven for 3-5 hours at a temperature of 100-120°C. The cast membrane preparation is carried out in a 100,000-class cleanroom to prevent dust and particles from adhering to the surface of the film. The casting machine is preheated for 2 hours, and the polyphenylene sulfide polyamide resin masterbatch is added when the temperature rises to 280-300°C. The temperature of the first section of the screw is set at 185-195°C, the temperature of the second section is set at 295-305, the temperature of the third section is set at 305-315°C, and the temperature of the fourth section is set at 305-315°C. The film winding drum temperature is set at 35-95°C and the speed is set at 10-200 mm / min, corresponding to a cast film thickness of 20-200 μm and a cast film width of 50-150 cm. After the cast film is wound, it enters the polyphenylene sulfide polyamide cast film pore-forming process.

[0076] Next, the polyphenylene sulfide polyamide cast film is subjected to porous film stretching according to different needs to obtain a uniaxial / biaxially stretched polyphenylene sulfide polyamide microporous membrane with the required pore size, porosity and thickness. The above cast film can be stretched to improve its crystallinity and obtain a thinner stretched film by uniaxial stretching and biaxial stretching. During uniaxial stretching, the stretching temperature is 85-15°C, the stretching ratio is 2, 3, 4, 5 and 6 times, and the stretching speed is 10-100 mm / min. After uniaxial stretching, the thickness of the film becomes 2-100 μm; during biaxial stretching, the following are selected: (1) the stretching ratio is 1*1, 1*2, 1*4, 2*2, 3*2 and 4*4; (2) the biaxial stretching temperature is 80-150°C, preferably 90-130°C; (3) the biaxial stretching speed is 5-80 mm / min; (4) the film thickness after biaxial stretching is 2-100 μm. After stretching, the mechanical properties and crystallinity of the film are generally improved, and the crystallization temperature and the flatness and smoothness of the film are also improved.

[0077] The fourth step in the manufacture of the polyphenylene sulfide polyamide porous membrane of the present invention is to dissolve part of the polyamide by steam etching of the polyphenylene sulfide polyamide film to obtain a hydrophilic polyphenylene sulfide polyamide microporous membrane. The obtained polyphenylene sulfide polyamide cast film is suspended and fixed on two electric rollers with a horizontal distance of 30-50 cm, and the rollers are 50-100 cm away from the bottom of the kettle. The film can be slowly wound from the first reel to the second reel at a certain speed. After the winding is completed, it can be retracted and wound onto the first reel, and can be circulated back and forth. The winding speed is 100-1000 mm / min. A certain amount of formic acid, phenol, and cresol are added to an acid-resistant ceramic kettle, and filled with nitrogen, carbon dioxide or hydrogen. The pressure reaches 0.005-0.1 MPa after sealing at room temperature. The heating process is then turned on, gradually raising the temperature inside the kettle. When it reaches 100-200°C and the pressure reaches 0.08-0.15 MPa, the film drum is powered on and slowly rotated, moving the film slowly through a mixture of saturated formic acid, phenol, or m-cresol and nitrogen, carbon dioxide, or hydrogen. This process is maintained for 0.5-6 hours. The film is then cooled to room temperature, and the vent valve is opened to release the nitrogen, carbon dioxide, or hydrogen. The acid-resistant ceramic kettle is opened, and the etched film is removed. After washing three times with anhydrous ethanol, it is wound on a drying winder (hot air temperature of 90-120°C). The formic acid, phenol, m-cresol, and ethanol used are recycled for future use. This process results in a polyphenylene sulfide polyamide cast membrane with pores ranging from 0.05-2.5 μm, resulting in a film with a defined pore size and porosity.

[0078] Those skilled in the art will understand that the specific process used in the above-mentioned specific embodiment (such as the specific operation method of steam etching the polyphenylene sulfide polyamide cast film, etc.) can be carried out in any alternative manner as long as it can prepare the polyphenylene sulfide polyamide hydrophilic porous membrane of the present invention and achieve the desired technical effect of the present invention.

[0079] The performance testing method used in the present invention is:

[0080] Melt index test: 315°C, 5k load, mass of the melt flowing out in 10 minutes (g / 10min).

[0081] Particle size test: Laser particle size analysis to measure particle size distribution (Topsizer laser particle size analyzer), dry powder test.

[0082] Thin film pore size test, SEM scanning.

[0083] Porosity: Electron microscopy method: The porosity of the material can be directly measured by observing the internal structure of the material under test through an electron microscope.

[0084] Film sheet thickness: Directly tested with electronic caliper (electronic thickness gauge).

[0085] Polarity-water contact angle:

[0086] The samples were prepared into 2 × 2 cm thin films for water contact angle measurements. Testing conditions were room temperature, using the sessile drop method with a 2 µL drop volume. Six replicates were measured on each film sample. Statistical analysis was performed using OriginPro 2022b. All data are presented as mean ± standard deviation. Normality was tested using the Kolmogorov-Smirnov method, homogeneity of variance was tested using the Levene method, and mean comparisons were performed using the Scheffe test in a one-way ANOVA.

[0087] The present invention is further described below with reference to specific examples, which, however, are not intended to limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0088] Example 1

[0089] (1) In a 100L reactor equipped with an anchor frame and spiral ribbon, add 45L of N-methyl-2-pyrrolidone, 10.40kg of sodium sulfide (60%), and 1kg of sodium hydroxide. Under nitrogen protection and stirring, gradually increase the temperature at a stirring speed of 80 rpm. Gradually increase the temperature to 150℃ to start dehydration. When the temperature rises to 201℃, 5.15kg of water is dehydrated. Cool down to 130℃, add 11.46kg of p-dichlorobenzene, 0.51kg of 2,5-dichlorobenzenesulfonyl chloride ( ), then 2.2 kg of PA66 was added. Under nitrogen protection and stirring at 100 rpm, the temperature was raised to 220°C for three hours, controlling the polymerization temperature between 220-235°C. The temperature was then raised to 250°C for three hours, controlling the polymerization temperature between 245-255°C, with stirring at 85 rpm. Flash evaporation was then performed to remove 30 L of solvent. The mixture was then cooled to 120°C, and 40 L of deionized water was added. The product was then washed six times with 80°C deionized water. The mixture was then washed twice with xylene and soaked in xylene for 30 minutes, maintaining stirring at 200 rpm. After the xylene washes, the mixture was washed twice with anhydrous ethanol and soaked in anhydrous ethanol for 30 minutes, maintaining stirring at 100 rpm. The xylene and ethanol were returned to the recovery system, and the product entered the drying process. The product was oven-dried at 100°C for 10 hours to obtain polyphenylene sulfide polyamide resin (PPS-PA66).

[0090] (2) Extrusion granulation of polyphenylene sulfide polyamide resin (PPS-PA66, AB type polyamide). The dried polyphenylene sulfide polyamide resin is extruded and granulated through a twin-screw extruder to form a masterbatch for cast film. The product is dried in a vacuum oven at 130°C for 5 hours before extrusion granulation. The extrusion temperature is 290-315°C, the screw speed is 200rpm, and the plasticizing time is maintained between 1-5 minutes. The extruded line product is cooled with high-purity deionized water and cut into pellets with a diameter of 2mm and a length of 3mm. It is then dried in a vacuum drying oven at 90°C for 10 hours as the masterbatch for cast film (PPS-PA66 pellets).

[0091] (3) The obtained polyphenylene sulfide polyamide resin masterbatch (PPS-PA66 pellets) was cast using a casting machine. Before casting, the polyphenylene sulfide polyamide resin masterbatch was dried in a vacuum oven for 3 hours at a temperature of 120°C. The cast film was prepared in a 100,000-class cleanroom to prevent dust and particles from adhering to the surface of the film. The casting machine was preheated for 2 hours. When the temperature rose to 290°C, the polyphenylene sulfide polyamide resin masterbatch was added. The screw was set to a temperature of 195°C in the first section, 300°C in the second section, 310°C in the third section, and 310°C in the fourth section. The film winding drum temperature was set to 45°C, the speed was 100 mm / min, and the corresponding cast film thickness was 50 μm. The cast film width was 60 cm. The cast film was stretched to increase its crystallinity. Uniaxial stretching was performed at a stretching temperature of 95°C, a stretching ratio of 4 times, and a stretching speed of 50 mm / min.

[0092] (4) The obtained polyphenylene sulfide polyamide cast film is hung and fixed on two electric rollers with a horizontal distance of 50 cm, and the rollers are 80 cm away from the bottom of the kettle. The film is slowly wound from the first roll to the second roll at a speed of 150 mm / min. After winding is completed, it can be retracted and wound onto the first roll, and the cycle is repeated. 5000 ml of formic acid is added to an acid-resistant ceramic kettle with an inner diameter of 1200 mm and filled with nitrogen. The pressure reaches 0.006 MPa after sealing at room temperature. Then turn on the heating, and the temperature in the kettle gradually increases. When the temperature reaches 110 ° C, the pressure rises to 0.1 MPa, and the film roller power is turned on. Keep for 5 hours. Then cool to room temperature, open the vent valve, and release nitrogen. Open the acid-resistant ceramic kettle and take out the etched film. After washing with anhydrous ethanol three times, it is wound on a dry winder (hot air temperature is (100 ° C). The used formic acid and ethanol are recycled for next use.

[0093] (5) Performance testing:

[0094] Performance test results:

[0095] Melt index (g / 10min): 80

[0096] Cast film sheet thickness (μm): 50±2.5

[0097] Uniaxially stretched film thickness (μm): 12.5±1.0

[0098] Pore ​​size of film after dissolution (μm): 5.0±0.5

[0099] Film porosity (%): 40

[0100] Film hydrophilic angle (°): 51

[0101] Biaxially oriented film thickness: 10.0±0.5

[0102] Pore ​​size of film after dissolution (μm): 4±0.5

[0103] Film porosity (%): 45

[0104] Film hydrophilic angle (°): 50

[0105] Example 2 (the difference from Example 1 is the different PA66 content)

[0106] Except that the amount of PA66 used was 3.3 kg, the other processes were the same as in Example 1.

[0107] Performance test results:

[0108] Melt index (g / 10min): 75

[0109] Cast film sheet thickness (μm): 50±2.5

[0110] Uniaxially stretched film thickness (μm): 15±1.0

[0111] Pore ​​size of film after dissolution (μm): 3.0±0.5

[0112] Film porosity (%): 45

[0113] Film hydrophilic angle (°): 46

[0114] Biaxially oriented film thickness: 10.0±0.5

[0115] Pore ​​size of film after dissolution (μm): 4±0.5

[0116] Film porosity (%): 49

[0117] Film hydrophilic angle (°): 46

[0118] Example 3 (the difference from Example 1 is the different PA66 content)

[0119] Except that the amount of PA66 used was 4.5 kg, the other processes were the same as in Example 1.

[0120] Performance test results:

[0121] Melt index (g / 10min): 65

[0122] Cast film sheet thickness (μm): 45±2.5

[0123] Uniaxially stretched film thickness (μm): 12±1.0

[0124] Pore ​​size of film after dissolution (μm): 5±0.5

[0125] Film porosity (%): 55

[0126] Film hydrophilic angle (°): 39

[0127] Biaxially oriented film thickness: 10.0±0.5

[0128] Pore ​​size of film after dissolution (μm): 3±0.5

[0129] Film porosity (%): 59

[0130] Film hydrophilic angle (°): 38

[0131] Example 4 (the difference from Example 1 is that type A polyamide PA6 is used instead of PA66)

[0132] Performance test results:

[0133] Melt index (g / 10min): 105

[0134] Cast film sheet thickness (μm): 50±2.5

[0135] Uniaxially stretched film thickness (μm): 12±1.0

[0136] Pore ​​size of film after dissolution (μm): 4.0±0.5

[0137] Film porosity (%): 41

[0138] Film hydrophilic angle (°): 52

[0139] Biaxially oriented film thickness: 10.0±0.5

[0140] Pore ​​size of film after dissolution (μm): 4±0.5

[0141] Film porosity (%): 46

[0142] Film hydrophilic angle (°): 50

[0143] Example 5 (the difference from Example 1 is that PA46 is used instead of PA66)

[0144] Performance test results:

[0145] Melt index (g / 10min): 72

[0146] Cast film sheet thickness (μm): 50±2.5

[0147] Uniaxially stretched film thickness (μm): 11±1.0

[0148] Pore ​​size of film after dissolution (μm): 3.0±0.5

[0149] Film porosity (%): 43

[0150] Film hydrophilic angle (°): 40

[0151] Biaxially oriented film thickness: 11±0.5

[0152] Pore ​​size of film after dissolution (μm): 4±0.5

[0153] Film porosity (%): 49

[0154] Film hydrophilic angle (°): 39

[0155] Example 6 (The difference from Example 1 is that the content of polar monomer used in synthesizing PPS-PA resin is different, and the amount used is twice that of Example 1)

[0156] (1) In a 100L reactor equipped with an anchor frame and spiral ribbon, add 45L of N-methyl-2-pyrrolidone, 10.40kg of sodium sulfide (60%), and 1kg of sodium hydroxide. Under nitrogen protection and stirring, gradually heat up at a stirring speed of 80 rpm. Gradually heat up to 150℃ to start dehydration. When the temperature rises to 201℃, 5.15kg of water is dehydrated. Cool down to 130℃, add 11.17kg of p-dichlorobenzene, 1.02kg of 2,5-dichlorobenzenesulfonyl chloride ( ), then 2.2 kg of PA66 was added. Under nitrogen protection and stirring at 100 rpm, the temperature was raised to 220°C for three hours, controlling the polymerization temperature between 220-235°C. The temperature was then raised to 250°C for three hours, controlling the polymerization temperature between 245-255°C, with stirring at 85 rpm. Flash evaporation was then performed to remove 30 L of solvent. The mixture was then cooled to 120°C, and 40 L of deionized water was added. The product was then washed six times with 80°C deionized water. The mixture was then washed twice with xylene and soaked in xylene for 30 minutes, maintaining stirring at 200 rpm. After the xylene washes, the mixture was washed twice with anhydrous ethanol and soaked in anhydrous ethanol for 30 minutes, maintaining stirring at 100 rpm. The xylene and ethanol were returned to the recovery system, and the product entered the drying process. The product was oven-dried at 100°C for 10 hours to obtain polyphenylene sulfide polyamide resin (PPS-PA66).

[0157] The other processes are the same as those in Example 1.

[0158] Performance test results:

[0159] Melt index (g / 10min): 89

[0160] Cast film sheet thickness (μm): 50±2.5

[0161] Uniaxially stretched film thickness (μm): 11±1.0

[0162] Pore ​​size of film after dissolution (μm): 4±0.5

[0163] Film porosity (%): 45

[0164] Film hydrophilic angle (°): 51

[0165] Biaxially oriented film thickness: 11±0.5

[0166] Pore ​​size of film after dissolution (μm): 3±0.5

[0167] Film porosity (%): 50

[0168] Film hydrophilic angle (°): 50

[0169] Example 7 (The difference from Example 1 is that the type of polar monomer used to synthesize the PPS-PA resin is different)

[0170] (1) In a 100L reactor equipped with an anchor frame and spiral ribbon, add 45L of N-methyl-2-pyrrolidone, 10.40kg of sodium sulfide (60%), and 1kg of sodium hydroxide. Under nitrogen protection and stirring, gradually heat up at a stirring speed of 80 rpm. Gradually heat up to 150℃ to start dehydration. When the temperature rises to 201℃, 5.15kg of water is dehydrated. Cool down to 130℃, add 11.46kg of p-dichlorobenzene, 0.415kg of 3,5-dichlorosalicylic acid ( ), then 2.2 kg of PA66 was added. Under nitrogen protection and stirring at 100 rpm, the temperature was raised to 220°C for three hours, controlling the polymerization temperature between 220-235°C. The temperature was then raised to 250°C for three hours, controlling the polymerization temperature between 245-255°C, with stirring at 85 rpm. Flash evaporation was then performed to remove 30 L of solvent. The mixture was then cooled to 120°C, and 40 L of deionized water was added. The product was then washed six times with 80°C deionized water. The mixture was then washed twice with xylene and soaked in xylene for 30 minutes, maintaining stirring at 200 rpm. After the xylene washes, the mixture was washed twice with anhydrous ethanol and soaked in anhydrous ethanol for 30 minutes, maintaining stirring at 100 rpm. The xylene and ethanol were returned to the recovery system, and the product entered the drying process. The product was oven-dried at 100°C for 10 hours to obtain polyphenylene sulfide polyamide resin (PPS-PA66).

[0171] The other processes are the same as those in Example 1.

[0172] Performance test results:

[0173] Melt index (g / 10min): 85

[0174] Cast film sheet thickness (μm): 45±2.5

[0175] Uniaxially stretched film thickness (μm): 12±1.0

[0176] Pore ​​size of film after dissolution (μm): 4.0±0.5

[0177] Film porosity (%): 45

[0178] Film hydrophilic angle (°): 45

[0179] Biaxially oriented film thickness: 10±0.5

[0180] Pore ​​size of film after dissolution (μm): 3±0.5

[0181] Film porosity (%): 45

[0182] Film hydrophilic angle (°): 43

[0183] Example 8 (The difference from Example 1 is that the type of polar monomer used to synthesize the PPS-PA resin is different)

[0184] (1) According to the schematic diagram of the response of the authority ( ) was carried out. In a 100L reactor equipped with an anchor frame and spiral ribbon, 45L of N-methyl-2-pyrrolidone, 10.40kg of sodium sulfide (60%), and 1kg of sodium hydroxide were added. The temperature was gradually raised under nitrogen protection and stirring at a stirring speed of 80 rpm. The temperature was gradually raised to 150°C to start dehydration. When the temperature was raised to 201°C, 5.15kg of water was dehydrated. The temperature was lowered to 130°C, and 11.46kg of p-dichlorobenzene and 0.466kg of 2,5-dichloroterephthalic acid ( ), then 2.2 kg of PA66 was added. Under nitrogen protection and stirring at 100 rpm, the temperature was raised to 220°C for three hours, controlling the polymerization temperature between 220-235°C. The temperature was then raised to 250°C for three hours, controlling the polymerization temperature between 245-255°C, with stirring at 85 rpm. Flash evaporation was then performed to remove 30 L of solvent. The mixture was then cooled to 120°C, and 40 L of deionized water was added. The product was then washed six times with 80°C deionized water. The mixture was then washed twice with xylene and soaked in xylene for 30 minutes, maintaining stirring at 200 rpm. After the xylene washes, the mixture was washed twice with anhydrous ethanol and soaked in anhydrous ethanol for 30 minutes, maintaining stirring at 100 rpm. The xylene and ethanol were returned to the recovery system, and the product entered the drying process. The product was oven-dried at 100°C for 10 hours to obtain polyphenylene sulfide polyamide resin (PPS-PA66).

[0185] The other processes are the same as those in Example 1.

[0186] Performance test results:

[0187] Melt index (g / 10min): 70

[0188] Cast film sheet thickness (μm): 45±2.5

[0189] Uniaxially stretched film thickness (μm): 10±1.0

[0190] Pore ​​size of film after dissolution (μm): 5.0±0.5

[0191] Film porosity (%): 40

[0192] Film hydrophilic angle (°): 40

[0193] Biaxially oriented film thickness: 5±0.5

[0194] Pore ​​size of film after dissolution (μm): 4±0.5

[0195] Film porosity (%): 45

[0196] Film hydrophilic angle (°): 39

[0197] Example 9 (the difference from Example 1 is the film dissolution time)

[0198] (1)-(3) are the same as in Example 1.

[0199] (4) The obtained polyphenylene sulfide polyamide cast film is hung and fixed on two electric rollers with a horizontal distance of 50 cm and a distance of 80 cm from the bottom of the kettle. The film is slowly wound from the first roll to the second roll at a speed of 150 mm / min. After winding, it can be retracted and wound onto the first roll, and the cycle is repeated. 5000 ml of formic acid is added to an acid-resistant ceramic kettle with an inner diameter of 1200 mm and filled with nitrogen. The pressure reaches 0.006 MPa after sealing at room temperature. Then the heating is turned on and the temperature in the kettle is gradually increased. When the temperature reaches 110 ° C, the pressure rises to 0.1 MPa, and the film roller power is turned on. Maintain for 1 hour. Then cool to room temperature, open the vent valve, and release the nitrogen. Open the acid-resistant ceramic kettle and take out the etched film. After washing three times with anhydrous ethanol, the film is wound on a dry winder (hot air temperature is (100 ° C). The used formic acid, phenol, m-cresol and ethanol are recycled for next use. After this process, the polyphenylene sulfide polyamide cast membrane is formed with a pore size of 0.05-5.0 μm.

[0200] Performance test results:

[0201] Melt index (g / 10min): 80

[0202] Cast film sheet thickness (μm): 50±2.5

[0203] Uniaxially stretched film thickness (μm): 12±1.0

[0204] Pore ​​size of film after dissolution (μm): 4.0±0.5

[0205] Film porosity (%): 40

[0206] Film hydrophilic angle (°): 40

[0207] Biaxially oriented film thickness: 4±0.5

[0208] Pore ​​size of film after dissolution (μm): 3±0.5

[0209] Film porosity (%): 45

[0210] Film hydrophilic angle (°): 39

[0211] Example 10 (the difference from Example 1 is that the film dissolution time is different)

[0212] (1)-(3) are the same as in Example 1.

[0213] (4) The obtained polyphenylene sulfide polyamide cast film is hung and fixed on two electric rollers with a horizontal distance of 50 cm and a distance of 80 cm from the bottom of the kettle. The film is slowly wound from the first roll to the second roll at a speed of 150 mm / min. After winding is completed, it can be retracted and wound onto the first roll, and the cycle is repeated. 5000 ml of formic acid is added to an acid-resistant ceramic kettle with an inner diameter of 1200 mm and filled with nitrogen. The pressure reaches 0.006 MPa after sealing at room temperature. Then turn on the heating, and the temperature in the kettle gradually increases. When the temperature reaches 110 ° C, the pressure rises to 0.1 MPa, and the film roller power is turned on. Maintain for 0.5 hours. Then cool to room temperature, open the vent valve, and release the nitrogen. Open the acid-resistant ceramic kettle and take out the etched film. After washing three times with anhydrous ethanol, the film is wound on a dry winder (hot air temperature is (100 ° C). The used formic acid, phenol, m-cresol and ethanol are recycled for next use. After this process, the polyphenylene sulfide polyamide cast membrane is formed with a pore size of 0.05-5.0 μm.

[0214] Performance test results:

[0215] Melt index (g / 10min): 80

[0216] Cast film sheet thickness (μm): 50±2.5

[0217] Uniaxially stretched film thickness (μm): 12±1.0

[0218] Pore ​​size of film after dissolution (μm): 4±0.5

[0219] Film porosity (%): 35

[0220] Film hydrophilic angle (°): 38

[0221] Biaxially oriented film thickness: 4±0.5

[0222] Pore ​​size of film after dissolution (μm): 3±0.5

[0223] Film porosity (%): 40

[0224] Film hydrophilic angle (°): 38

[0225] Comparative Example 1: Traditional polyphenylene sulfide

[0226] (1) In a 100L reactor equipped with an anchor frame and spiral ribbon, add 45L of N-methyl-2-pyrrolidone, 10.40kg of sodium sulfide (60%), and 1kg of sodium hydroxide. Under nitrogen protection and stirring, gradually heat up at a stirring speed of 80 rpm. Gradually heat up to 150℃ to start dehydration. When the temperature rises to 201℃, 5.15kg of water is dehydrated. Cool down to 130℃ and add 11.76kg of p-dichlorobenzene. Under nitrogen protection and stirring at a stirring speed of 100 rpm, heat up to 220℃ and react for 3 hours. Control the polymerization temperature at 220-235℃. Heat up to 250℃ and react for 3 hours. Control the polymerization temperature at 245-255℃. Stir at a stirring speed of 85 rpm. Then flash evaporate and distill off 30L of solvent. Then cool to 120℃ and add 40L of deionized water. The product is washed 6 times with 80℃ deionized water. The product is washed twice with xylene and soaked in xylene for 30 minutes, stirring at 200 r / min. After the xylene washes, it is washed twice with anhydrous ethanol and soaked in anhydrous ethanol for 30 minutes, stirring at 100 r / min. The xylene and ethanol are returned to the recovery system, and the product enters the drying process. The product is dried in a 100°C oven for 10 hours to obtain traditional polyphenylene sulfide resin (PPS).

[0227] The other processes are the same as in Example 1.

[0228] Performance test results:

[0229] Melt index (g / 10min): 70

[0230] Cast film sheet thickness (μm): 35±2.5

[0231] Uniaxially stretched film thickness (μm): 15±2.5

[0232] Film pore size (μm): almost non-porous

[0233] Film porosity (%): less than 1

[0234] Film hydrophilic angle (°): 98

[0235] Biaxially oriented film thickness (μm): 5.0±0.5

[0236] Pore ​​size of film after dissolution (μm): almost non-porous

[0237] Porosity of film after dissolution (%): less than 1

[0238] Film hydrophilic angle (°): 96

[0239] Comparative Example 2: Type A polyamide PA6

[0240] PA6 (275° C., 5 kg test) with a melt index of 30 (g / 10 min) was used to draw the film according to Example 1 and then etch it.

[0241] Test results: The film was completely dissolved and PA6 was not resistant to formic acid corrosion.

[0242] Comparative Example 3: AB type polyamide PA66

[0243] PA66 (275° C., 5 kg test) with a melt index of 50 (g / 10 min) was used to draw the film according to Example 1 and then etch it.

[0244] Test results: The film was completely dissolved and PA66 was not resistant to formic acid corrosion.

[0245] Comparative Example 4: Preparation of microporous membrane using PPS-PA6 material formed by extrusion blending (polyamide type A)

[0246] Similar to Example 1, 8 kg of conventional polyphenylene sulfide and 2 kg of PA6 were extruded through a twin-screw extruder, and then film-drawing, etching, and testing were performed according to the process of Example 1.

[0247] Melt index (g / 10min): 92

[0248] Cast film sheet thickness (μm): 55±2.5

[0249] Uniaxially stretched film thickness (μm): 15±2.5

[0250] Pore ​​size of film after dissolution (μm): 3.5-200±1.0

[0251] Film porosity (%): 30

[0252] Film hydrophilic angle (°): 45

[0253] Biaxially oriented film thickness (μm): 5.0±0.5

[0254] Pore ​​size of film after dissolution (μm): 4.5-250±0.5

[0255] Porosity of film after dissolution (%): 35

[0256] Film hydrophilic angle (°): 45

[0257] The PA6 is unevenly distributed by this extrusion blending method. Some places aggregate, resulting in large pores in the etched holes, while some places have no holes, and the size and distribution of the holes are uneven.

[0258] Comparative Example 5: Preparation of microporous membrane using PPA-PA66 material formed by extrusion blending (AB type polyamide)

[0259] Similar to Example 1, 8 kg of conventional polyphenylene sulfide and 2 kg of PA66 were extruded through a twin-screw extruder, and then film-drawing, etching, and testing were performed according to the process of Example 1.

[0260] Test results:

[0261] Melt index (g / 10min): 92

[0262] Cast film sheet thickness (μm): 50±2.5

[0263] Uniaxially stretched film thickness (μm): 15±2.5

[0264] Pore ​​size of film after dissolution (μm): 3.5-200±1.0

[0265] Film porosity (%): 30

[0266] Film hydrophilic angle (°): 40

[0267] Biaxially oriented film thickness (μm): 5±0.5

[0268] Pore ​​size of film after dissolution (μm): 4.5-250±1.0

[0269] Porosity of film after dissolution (%): 35

[0270] Film hydrophilic angle (°): 40

[0271] This extrusion blending method results in uneven distribution of PA66. Some areas aggregate, resulting in large pores in the etched holes, while some areas have no pores, and the pore size and distribution are uneven.

[0272] It should be noted that the preferred embodiments of the present invention are given in the specification and drawings of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to be additional limitations on the content of the present invention. The purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all considered to be within the scope of the description of the present invention; further, for ordinary technicians in this field, without departing from the above-mentioned technical ideas of the present invention, various improvements, replacements or changes can be made based on the common technical knowledge and customary means in this field, and all these improvements, replacements or changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a hydrophilic polyphenylene sulfide polyamide microporous membrane, characterized in that: The following steps are involved: (1) Using sulfur-containing monomers, dihalogen aromatic compounds and polar dihalogen aromatic compounds as synthetic raw materials for polyphenylene sulfide, polymerizing them together with polyamide in a polar aprotic solvent under the protection of inert gas, recovering the solvent, and washing, purifying and drying the reaction product to obtain polyphenylene sulfide polyamide resin; (2) Extruding and granulating the dried polyphenylene sulfide polyamide resin through a twin-screw extruder to form a masterbatch for cast film; (3) the masterbatch obtained in the drying step (2) is subjected to a film casting method, and uniaxial stretching or biaxial stretching is performed to increase the crystallinity to obtain a polyphenylene sulfide polyamide cast film; (4) The polyphenylene sulfide polyamide cast film obtained in step (3) is subjected to steam etching to dissolve a portion of the polyamide to obtain a hydrophilic polyphenylene sulfide polyamide microporous membrane.

2. The preparation method according to claim 1, characterized in that The dihalogen aromatic compound is selected from at least one of 1,4-dihalobenzene, 2,4-dihalobenzene, 3,5-dihalobenzene, 4,4'-dihalobenzene, 4,4'-dihalobiphenyl, 4,4'-dihalodiphenyl sulfone, 4,4'-dihalobenzophenone or 4,4'-dihalodiphenyl ether; Further, the polar dihalogen aromatic compound has a polar functional group selected from hydroxyl, amino, carboxyl, sulfonic acid, sulfonyl chloride and combinations thereof; Furthermore, the polar dihalogen aromatic compound is selected from at least one of the following: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 , wherein X is a halogen atom, and Z, Z1 and Z2 are each independently a hydroxyl group, an amino group, a carboxyl group, a sulfonic acid group or a sulfonyl chloride group; Furthermore, the molar ratio of the polar dihalogen aromatic compound to the dihalogen aromatic compound is 2.5-10.0:97.5-90.

0.

3. The preparation method according to claim 1, characterized in that The sulfur-containing monomer is selected from at least one of sodium sulfide, hydrogen sulfide, sodium hydrosulfide or sulfur; Furthermore, in the polymerization reaction system, the molar ratio of divalent sulfide ions to the total amount of dihalogen aromatic compounds and polar dihalogen aromatic compounds is 0.95-1.05:1.

0.

4. The preparation method according to claim 1, characterized in that The polyamide includes A-type polyamide or AB-type polyamide; The structure of the A-type polyamide is shown in formula (I): (I) Where m = 4-12; The structure of the AB type polyamide is shown in formula (II): (II) Where m1 and m2 = 4-12; Furthermore, the polyamide is selected from at least one of PA6, PA46, PA66 and PA1010; Furthermore, the mass ratio of the amount of polyamide to the theoretical synthesis amount of polyphenylene sulfide is 20-50:80-50; Furthermore, the added polyamide is in the form of a masterbatch with a diameter of less than 3 mm after granulation or small particles with a particle size of less than 3 mm before granulation.

5. The preparation method according to claim 1, characterized in that The polar aprotic solvent is selected from sulfone or sulfone compounds, amine compounds or lactam compounds; Further, the polar aprotic solvent is selected from at least one of N-methyl-2-pyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone, 1,3-dimethyl-2-imidazolone, hexamethylphosphoramide, N,N-dimethylacetamide, N,N-dimethylamide, caprolactam, N-ethylcaprolactam, N,N-vinylpyrrolidone, 1,3-dimethyl-2-imidazolidinone lactam, tetramethylurea, dimethyl sulfoxide and sulfolane; Furthermore, the amount of the polar aprotic solvent is: per mole of theoretical synthesis amount of polyphenylene sulfide, the amount of solvent is 0.5-1.0 L.

6. The preparation method according to claim 1, characterized in that The step (1) comprises: firstly subjecting the sulfur-containing monomer to a dehydration reaction in a polar aprotic solvent under the protection of an inert gas; then adding a dihalogen aromatic compound and a polar dihalogen aromatic compound and then adding polyamide, and then conducting a polymerization reaction; Furthermore, the temperature of the dehydration reaction is controlled at 175-205°C, and after the dehydration is completed, the temperature is reduced to below 150°C before adding other materials; Furthermore, depending on the sulfur-containing monomer used, a base is optionally added to the dehydration reaction; Furthermore, the polymerization reaction temperature is 200-300° C., and the reaction time is 3-12 hours; Furthermore, the polymerization reaction comprises first reacting at 200-250°C, preferably 220-235°C for 2-6 hours, and then reacting at 235-300°C, preferably 245-255°C for 3-6 hours; Furthermore, stirring is maintained during the polymerization reaction, and the stirring speed is maintained at 80-220 r / min; Furthermore, the washing purification comprises washing the reaction product with deionized water, xylene and anhydrous ethanol in sequence.

7. The preparation method according to claim 1, characterized in that The extrusion temperature of the extrusion granulation in step (2) is 285-325°C, the screw speed is between 100-300 rpm, and the plasticizing time is maintained between 1-5 minutes.

8. The preparation method according to claim 1, characterized in that In the process of forming the film by the casting method described in step (3), a casting machine is used to draw the film, and the temperatures of the first to fourth sections of the screw are 185-195°C, 295-305°C, 305-315°C and 2305-315°C, the temperature of the film receiving roller is 35-95°C, the rotation speed is 10-200 mm / min, and the corresponding cast film thickness is 20-200 μm and the cast film width is 50-150 cm; Furthermore, the stretching temperature of the uniaxial stretching is 85-15°C, the stretching ratio is 2, 3, 4, 5 and 6 times, the stretching speed is 10-100 mm / min, and the thickness of the film after uniaxial stretching is 2-100 μm; Furthermore, the stretching ratio of the biaxial stretching is 1*1, 1*2, 1*4, 2*2, 3*2 and 4*4, the stretching temperature is 80-150°C, preferably 90-130°C, the stretching speed is 5-80 mm / min, and the film thickness after biaxial stretching is 2-100 μm.

9. The preparation method according to claim 1, characterized in that The steam etching in step (4) includes treating the polyphenylene sulfide polyamide cast film in an atmosphere of nitrogen, carbon dioxide or hydrogen in the vapor of formic acid, phenol or cresol at 100-200°C and 0.08-0.15 MPa for 0.5-6 hours to obtain a hydrophilic polyphenylene sulfide polyamide microporous membrane with a pore size of 0.05-10.0 μm.

10. A hydrophilic polyphenylene sulfide polyamide microporous membrane prepared by the preparation method according to any one of claims 1 to 9.

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