Polymer film with hydrophilic pore channels as well as preparation method and application of polymer film

Abstract

According to the polymer film with the hydrophilic pore channels, the pore channels are hydrophilic, the contact angle of water on the inner walls of the pore channels is smaller than 30 degrees, the pore size ranges from 50 nm to 100 [mu] m, and the thickness range of the polymer film ranges from 1 [mu] m to 10 mm. The preparation method comprises the following steps: by using polymer particles of which the surfaces are modified with hydrophilic polyelectrolyte multilayer films as raw materials, preparing the polymer particles into a polymer film containing hydrophilic pore channels by adopting a common hot press molding method; and the prepared polymer film has excellent mechanical properties and can meet related application requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer chemical materials, and in particular relates to a polymer film with hydrophilic pores, a preparation method and application thereof. Background Art

[0002] The hydrophilic pore film is a hydrophilic functional material with a porous structure, which has broad application prospects in water treatment, biomedicine, catalysis and other fields. Compared with traditional hydrophobic polymer films, the hydrophilic pore film has better advantages in water treatment, blood purification, drug delivery and other fields because its hydrophilic pores can be better wetted by water phase and avoid the obstruction of water flow caused by adsorbed air in the pores.

[0003] At present, the main methods for preparing films with hydrophilic channels include chemical methods such as chemical modification and surface oxidation, as well as physical methods such as surface coating and plasma treatment. However, these methods have the following shortcomings:

[0004] 1. The preparation process of chemical modification and surface oxidation methods is complicated, the hydrophilicity is not durable enough, it is difficult to control, and the biocompatibility is poor.

[0005] 2. Surface coating and plasma treatment methods may destroy the structure of polymer films, resulting in impairment of their mechanical properties.

[0006] Therefore, there is an urgent need to develop a method for preparing a hydrophilic pore film with a simple preparation process, long-lasting and controllable hydrophilicity, good biocompatibility and the ability to maintain good mechanical properties of the polymer film. Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the present invention provides a method for preparing a polymer film containing hydrophilic pores by using a hydrophilic polyelectrolyte to controllably hydrophilize the surface of a hydrophobic polymer particle.

[0008] The advantages of the present invention are:

[0009] The method is simple and easy to implement and can be used to prepare various polymer films containing hydrophilic pores. The prepared polymer films have good mechanical properties and hydrophilicity.

[0010] This method can avoid the obstruction of liquid flow caused by gas adsorbed on the hydrophobic pore walls of the pores in the process of modifying the hydrophilic polyelectrolyte multilayer membrane in the traditional hydrophobic porous polymer film. Thus, a polymer film with good mechanical properties and hydrophilic pores is obtained. The hydrophilicity of the pores of the porous film prepared by the above method can also be achieved by regulating the number of layers of the polyelectrolyte multilayer membrane modified on the surface of the polymer particles.

[0011] Specifically:

[0012] The first aspect of the present invention is to provide a polymer film with hydrophilic pores, wherein the pores are hydrophilic, and the contact angle of water on the inner wall of the pores is less than 30°. The contact angle of water on the inner wall of the pores can be regulated by regulating the coverage of the polyelectrolyte multilayer film coated on the surface of the polymer particles; the diameter of the pores is 50nm~100μm, preferably 100nm~50μm; the thickness of the polymer film with hydrophilic pores ranges from 1μm to 10mm, preferably in the range of 10μm to 5mm.

[0013] The second aspect of the present invention is to provide a method for preparing the polymer film with hydrophilic channels as described in the first aspect of the present invention, using polymer particles with surface modified hydrophilic polyelectrolyte multilayer membrane as raw materials, and adopting a hot pressing molding method to prepare it into a polymer film containing hydrophilic channels.

[0014] Specifically, the preparation method comprises the following steps:

[0015] Step 1: Modify the hydrophilic polyelectrolyte multilayer onto the surface of polymer particles using a layer-by-layer assembly method;

[0016] Step 2: Using a hot pressing method, the polymer particles modified with the hydrophilic polyelectrolyte multilayer film are prepared into a polymer film containing hydrophilic channels.

[0017] In the present invention, hydrophobic polymer particles with hydrophilic polyelectrolyte multilayer films modified on the surface are used as raw materials, and then the hydrophilic pore-containing polymer film is prepared by polymer hot pressing molding method.

[0018] In the present invention, the hydrophobic polymer particle materials used include the following commonly used thermoplastic polymers and their copolymers and their derivatives; the thermoplastic polymers include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polycarbonate (PC), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyurethane (PU), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), polyethersulfone (PES), cycloolefin copolymer (COC), styrene-acrylic resin (SAN), styrene-methyl methacrylate (MS), nylon (Nylon), polyethylene terephthalate (PET), polyoxymethylene (POM), polyphosphate (PPE), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer (MBS), etc. In an air environment, the contact angle of a water drop on the surface of the polymer particle is 60°-120°; the size of the polymer particle is 50nm-500μm, preferably 100nm-100μm.

[0019] In the present invention, in step 1, the coverage of the hydrophilic polyelectrolyte multilayer film on the surface of the polymer particle material is 0-100%, and the preferred coverage is 5% to 85%.

[0020] In the present invention, in step 1, the number of layers of the hydrophilic polyelectrolyte multilayer membrane is 1-100.

[0021] In the present invention, in step 1, the layer-by-layer assembly method comprises: respectively preparing polyelectrolytes with opposite charges into polyelectrolyte polymer aqueous solution A and polyelectrolyte polymer aqueous solution B, and sequentially cyclically coating the polyelectrolyte polymer aqueous solution A and the polyelectrolyte polymer aqueous solution B on the surface of the polymer particle material to form a hydrophilic polyelectrolyte multilayer film; the polyelectrolytes with opposite charges include polycationic electrolytes and polyanionic electrolytes.

[0022] In the present invention, in step 1, the polycationic electrolyte includes one or more water-soluble positively charged polycationic polymers such as polydiallyldimethylammonium chloride (PDADMAC), polyethyleneimine (PEI), polyallylamine hydrochloride (PAH), chitosan (CS), etc. The molecular weight of the polycationic electrolyte is 10,000 to 1,000,000, preferably 50,000 to 500,000.

[0023] In the present invention, in step 1, the polyanion electrolyte includes one or more of anionic polyelectrolyte polymers such as sodium polystyrene sulfonate (PSS), sodium polyvinyl sulfonate (PVS), polyacrylic acid (PAA), polymethacrylic acid (PMA), sodium carboxymethyl cellulose (CMC-Na), polymethacrylic acid (PMAA), poly(2-vinylpyridine) (P2VP), poly(4-vinylpyridine) (PVP), polymaleic acid (PMA), polypeptide, protein, DNA or sodium alginate. Its molecular weight is 2000-1 million, preferably 6000-200000.

[0024] In the present invention, the concentration of the polyelectrolyte polymer aqueous solution A and / or the polyelectrolyte polymer aqueous solution B is 0.01-20 g / L, preferably 0.5-10 g / L; the concentration of the inorganic salt contained is 0-5 mol / L, preferably 0-1 mol / L.

[0025] In the present invention, the hot pressing pressure used in step 2 is 1MPa to 1000MPa, preferably 1MPa to 100MPa; the holding time is 1min to 360min, preferably 10min to 60min; the temperature is 80℃ to 280℃, preferably 100℃ to 200℃.

[0026] In the present invention, during the hot pressing process in step 2, polymer materials or metal gauze can be added to increase the toughness of the polymer film and avoid the occurrence of cracks; or inorganic nanomaterials can be added to increase its resistance to acid, alkali and organic solvent corrosion.

[0027] The polymer film containing hydrophilic channels prepared by this patent can be further modified by chemical or physical methods to obtain a polymer film containing hydrophilic channels with different functions.

[0028] The third aspect of the present invention is that the polymer film with hydrophilic pores described in the first and second aspects of the present invention has wide applications in water treatment, biomedicine, catalysis and other fields, especially in water treatment, blood purification, drug delivery and other fields.

[0029] In summary, the present invention provides a method for preparing a polymer film containing hydrophilic channels by using a hydrophilic polyelectrolyte to controllably hydrophilize the surface of polymer particles. The method is simple and easy to implement, and can prepare various types of polymer films containing hydrophilic channels. The prepared films have good mechanical properties and hydrophilicity, and are suitable for various aqueous phase applications.

[0030] The present invention has the following technical effects:

[0031] 1. The polymer porous film prepared by the present invention has hydrophilic pores and can be directly used for related research in the liquid phase.

[0032] 2. The polymer film containing hydrophilic channels prepared by the present invention has excellent mechanical properties and meets relevant requirements. The mechanical properties are comparable to those of porous films prepared by using surface unmodified polyelectrolyte multilayer membranes, and are superior to the mechanical properties of films obtained by hydrophilizing the channels of traditional polymer films using physical or chemical methods. DETAILED DESCRIPTION

[0033] In order to further understand the present invention, the preferred technical scheme of the present invention is described in detail with specific examples below. The reagents and raw materials used in the following examples and test examples are all industrial pure commodities, and the equipment used are all commonly used equipment and devices in the field.

[0034] Example 1

[0035] Step 1: 5000g of polytetrafluoroethylene polymer particles with a particle size of 100nm are placed in a 10L degassed aqueous solution of a polycationic electrolyte polydiallyldimethylammonium chloride (PDADMAC) with a concentration of 0.5g / L and a molecular weight of 50,000 and allowed to stand for 10 minutes. The content of inorganic salt in the polymer solution is 0.5mol / L. The polymer particles are then washed with clean water to remove the unabsorbed cationic polymers and dried with N2. The above process obtains polymer particles modified with n=1 layers of polyelectrolyte multilayer membranes.

[0036] Step 2: Place the polymer particles modified with n=1 layers of polyelectrolyte multilayer membrane obtained in step 1 into a 10L degassed aqueous solution of anionic electrolyte sodium polystyrene sulfonate (PSS) with a concentration of 1g / L and a molecular weight of 100,000 and allow to stand for 10 minutes. The content of inorganic salt in the polymer solution is 0.5mol / L. Wash the unabsorbed anionic polyelectrolyte with clean water and dry with N2. The above process obtains polymer particles modified with n=2 layers of polyelectrolyte multilayer membrane.

[0037] Step 3: After repeating the above steps 1 and 2 for 20 cycles, polytetrafluoroethylene particles with n=40 layers of polyelectrolyte multilayer films modified on the surface can be obtained, and the coverage rate of the hydrophilic polyelectrolyte polymer on the surface is 100%.

[0038] Step 4: Put the polytetrafluoroethylene particles with a surface coverage of 100% of the hydrophilic polyelectrolyte multilayer membrane obtained in step 3 into the mold of a hot press, place a 150-mesh polyphenylene sulfide gauze in the middle to prevent cracking, and maintain it at 200°C and a pressure of 30MPa for 60 minutes to obtain a polytetrafluoroethylene film containing hydrophilic channels with a pore size of 100nm, a thickness of 10μm, and a contact angle of water on the inner wall of the channel of 15°.

[0039] The film prepared by the method can effectively intercept macromolecular substances such as proteins and bacteria, and can be used in the fields of food, medicine, biotechnology, etc. for clarifying, concentrating and purifying liquids.

[0040] Example 2

[0041] Step 1: Put 1000g of polystyrene particles with a particle size of 50μm and 2500g of polypropylene polymer with a particle size of 30μm into the coating pot of the coating machine. At a rotation speed of 20rpm, spray 500ml of a polycation electrolyte polyallylamine hydrochloride (PAH) solution with a concentration of 5g / L, a polymer molecular weight of 500,000, and an inorganic salt content of 0mol / L onto the surface of the polymer particles. After washing with water, dry with hot air at a temperature of 70℃ to obtain polymer particles with n=1 layers of polyelectrolyte multilayer film modified on the surface.

[0042] Step 2: Spray 500 ml of polyanion electrolyte polyacrylic acid (PAA) with a concentration of 5 g / L, a molecular weight of 200,000, and an inorganic salt content of 0 mol / L onto the surface of the polymer particles prepared in step 1. After washing with clean water, dry with hot air at a temperature of 70°C to obtain polymer particles with n=2 layers of polyelectrolyte multilayer films modified on the surface.

[0043] Step 3: After repeating the above steps 1 and 2 for 10 times, polystyrene and polypropylene particles with n=20 layers of polyelectrolyte multilayer films modified on the surface can be obtained, wherein the coverage of the polyelectrolyte multilayer films on the surface is 70% and 65%, respectively.

[0044] Step 4: The polystyrene and polypropylene particles prepared in step 3 whose surfaces are modified with n=20 layers of polyelectrolyte multilayer films are prepared into a slurry, which is then sprayed onto both sides of the polyphenylene sulfide (PPS) gauze, respectively. The slurry is placed in a mold of a hot press, and a pressure of 100 MPa is applied at 100°C for 10 minutes to obtain a polystyrene / polyphenylene sulfide / polypropylene polymer membrane containing hydrophilic channels with a thickness of 100 μm and a pore size of 30 μm. The contact angle of water on the inner wall of the channel is 12°.

[0045] The film prepared by the method can be used as a pretreatment diaphragm for seawater desalination equipment to filter common impurities such as sand and seaweed in seawater.

[0046] Example 3

[0047] Step 1: Place 500 g of polyphenylene sulfide polymer particles with a particle size of 2 μm into 1 L of polyanion electrolyte sodium alginate aqueous solution with a concentration of 0.5 g / L, a molecular weight of 50,000, and an inorganic salt content of 0 mol / L. After strong stirring, wash with deionized water and dry to obtain polymer particles with a surface modified with n=1 layers of polyelectrolyte multilayer film.

[0048] Step 2: Place the polymer particles obtained in step 1 into 1L of a polycation electrolyte chitosan aqueous solution with a concentration of 0.5g / L, a molecular weight of 50,000, and an inorganic salt content of 0mol / L. After vigorous stirring, use an electrostatic spray drying method to make chitosan molecules adhere to the surface, wash with deionized water, and after drying, obtain polymer particles with n=2 layers of polyelectrolyte multilayer films modified on the surface.

[0049] Step 3: After repeating the process of step 1 and step 2 for 20 times, polyphenylene sulfide particles with n=40 layers of polyelectrolyte multilayer films modified on the surface can be obtained, wherein the coverage rate of the hydrophilic polyelectrolyte multilayer films on the surface reaches 80%.

[0050] Step 4: The polyphenylene sulfide particles modified with the polyelectrolyte multilayer film are heat-pressed onto a 60-mesh polypropylene gauze at a speed of 1 mm / min using a double-roll hot press at 200°C and a pressure of 50 MPa to form a polymer film containing hydrophilic pores. The contact angle of water on the inner wall of the pores of the film is 15°, the pore size is about 1 μm, and the thickness is 50 μm.

[0051] The hydrophilic porous film prepared by the method is used for filtering fresh juice and for separating pulp and juice in squeezed juice.

[0052] Example 4

[0053] Step 1: 2000g of polycarbonate particles with a particle size of 1μm are placed in 1L of a degassed polyethyleneimine (PEI) aqueous solution with a concentration of 10g / L, a molecular weight of 500,000, and an inorganic salt content of 1mol / L, and after standing for 20 minutes, washed with clean water and dried. Polymer particles with n=1 layers of polyelectrolyte multilayer films modified on the surface are obtained.

[0054] Step 2: Soak the polycarbonate particles obtained in step 1 in 1L of a polystyrene sulfonate (PSS) aqueous solution with a concentration of 5g / L, a molecular weight of 200,000, and an inorganic salt content of 1mol / L, and let it stand for 15 minutes, then wash with clean water and dry to obtain polymer particles with n=2 layers of polyelectrolyte multilayer films modified on the surface.

[0055] Step 3: Repeat the process of step 1 to obtain polymer particles with n=3 layers of polyelectrolyte multilayer films modified on the surface. The coverage rate of the hydrophilic polyelectrolyte multilayer films on the surface reaches 30%.

[0056] Step 4: The polycarbonate particles modified with n=3 layers of polyelectrolyte multilayer membrane obtained in step 3 were hot pressed at 100°C and 100 MPa for 60 min. A hydrophilic pore-containing polymer film with a thickness of 100 μm and a pore size of 5 μm was obtained, and the contact angle of water on the inner wall of the pore was 16°.

[0057] The hydrophilic porous film is used for filtrates containing active ingredients in fermentation tanks in the pharmaceutical field.

[0058] Example 5

[0059] Step 1: Pour 8000g of polyetheretherketone (PEEK) particles with a particle size of 100μm and 2500g of polymethyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer (ABS) polymer particles with a particle size of 100μm into a coating pan. At a rotation speed of 20rpm, spray 50ml of polyanionic electrolyte polyacrylic acid (PAA) with a concentration of 1g / L, a molecular weight of 6000, and an inorganic salt content of 0.5mol / L onto the surface of the polymer particles. Wash the polymer particles with water and dry them with hot air (temperature of 70°C). Get polymer particles with n=1 layers of polyelectrolyte multilayer film modified on the surface. The surface coverage of the polyelectrolyte multilayer film reaches 5%.

[0060] Step 2: Put the PEEK and ABS polymer particles modified with n=1 layers of polyelectrolyte multilayer membrane in step 1 into a double-roll hot press, place a 50-mesh stainless steel mesh in the middle, with a spacing of 5mm, and apply a pressure of 50MPa at 180°C at a speed of 10μm / min. After cooling, remove the mold to obtain a polymer membrane containing hydrophilic channels. The contact angle of water on the inner wall of its channels is 28°, the thickness is 5mm, and the pore size is 70μm.

[0061] Example 6

[0062] Step 1: Place 5000g of polyvinylidene fluoride (PVDF) particles with a particle size of 1μm into 1L of a degassed aqueous solution of anionic electrolyte sodium polystyrene sulfonate (PSS) with a concentration of 10g / L, a molecular weight of 200,000, and an inorganic salt content of 1mol / L, and let it stand for 10 minutes. Wash with clean water and dry to obtain polyvinylidene fluoride (PVDF) particles with a surface modified with n=1 layers of polyelectrolyte multilayer film.

[0063] Step 2: The particles obtained in step 1 are again placed in 1L of a degassed aqueous solution of a polycationic electrolyte polyethyleneimine (PEI) with a concentration of 10g / L, a molecular weight of 500,000, and an inorganic salt content of 0mol / L, and allowed to stand for 20 minutes. The particles are then washed with clean water and dried to obtain polyvinylidene fluoride (PVDF) particles with a surface modified with n=2 layers of polyelectrolyte multilayer films.

[0064] Step 3: Repeat the process of step 1 and step 2 for 3 cycles to obtain polyvinylidene fluoride (PVDF) particles with n=6 layers of polyelectrolyte multilayer membranes modified on the surface, and the coverage of the polyelectrolyte multilayer membranes is 70%.

[0065] Step 4: Put the polyvinylidene fluoride (PVDF) particles modified with polyelectrolyte multilayer membrane into a hot press molding machine, place a 50-mesh PVC gauze in the middle, and maintain pressure at 200°C for 60 minutes to obtain a polymer film containing hydrophilic pores, the contact angle of water on the inner wall of the pores is 25°, the pore size is 50 μm, and the thickness is 5 mm. The hydrophilic porous film is used to filter impurities such as gravel in the water phase.

[0066] Example 7

[0067] Step 1: 1800g of polymethyl methacrylate (PMMA) with a particle size of 10μm and 2500g of polyethylene terephthalate (PET) polymer particles with a particle size of 50μm are placed in the hopper of a coating machine. At a rotation speed of 20rpm, 500ml of a cationic polyallylamine hydrochloride (PAH) solution with a concentration of 1g / L, a molecular weight of 100,000, and an inorganic salt concentration of 1mol / L is sprayed onto the surface of the polymer particles. After washing with water, the particles are dried with hot air at 70°C to obtain hydrophilic polyelectrolyte-modified polymer particles with a layer number n=1.

[0068] Step 2: Spray 500 ml of a polyanionic electrolyte polyacrylic acid (PAA) solution with a concentration of 0.5 g / L, a molecular weight of 6000, and an inorganic salt concentration of 1 mol / L onto the surface of the polymer particles, and dry them with hot air at 40°C to obtain hydrophilic polyelectrolyte-modified polymer particles with a layer number of n=2. The coverage of the polyelectrolyte multilayer film on the surface of polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET) is 10% and 11%, respectively.

[0069] Step 3: Put the above-mentioned polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET) particles with n=2 layers of hydrophilic polyelectrolyte multilayer films on the surface into 100°C and 50MPa pressure for 60 minutes, and then place a 100-mesh polypropylene gauze in the middle to obtain a polymer film containing hydrophilic pores. The contact angle of water on the inner wall of the pores is 15°, the pore size is 10μm, and the thickness is 1mm.

[0070] Step 4: Place the above film into 1L of a cationic electrolyte polyethyleneimine (PEI) solution with a concentration of 1g / L and a molecular weight of 100,000, let it stand for 10 minutes, then wash it with a hydrophilic detergent and dry it.

[0071] Step 5: Place the polymer film containing hydrophilic pores obtained in step 4 into 1L of anionic electrolyte sodium polyvinyl sulfonate (PVS) solution with a concentration of 1g / L and a molecular weight of 6000, let it stand for 10 minutes, then wash it with a hydrophilic detergent and dry it.

[0072] Step 6: Repeat steps 4 and 5 for 3 times to obtain a polyelectrolyte multilayer membrane containing hydrophilic pores. The contact angle of water on the inner wall of the pores is 5° and the thickness is 1 mm.

[0073] The hydrophilic porous film can be used for drug coating and as a sustained-release carrier for drug molecules.

[0074] Example 8

[0075] Step 1: 1500g of 50μm styrene-methyl methacrylate (MS), 1000g of 70μm nylon (Nylon) and 500g of 5μm polyphenylene oxide (PPO) polymer particles are placed in 1L of a degassed polystyrene sulfonate sodium (PSS) aqueous solution with a concentration of 10g / L, a polymer molecular weight of 500,000 and an inorganic salt content of 1mol / L, and allowed to stand for 20 minutes, then washed with clean water and dried. This is recorded as a polymer particle with a surface modification of n=1 layer of hydrophilic polyelectrolyte.

[0076] Step 2: The particles obtained in step 1 are again placed in 1L of degassed polyethyleneimine (PEI) aqueous solution with a concentration of 10g / L, a molecular weight of 500,000, and an inorganic salt content of 1mol / L, and allowed to stand for 20 minutes, then washed with clean water and dried. This is recorded as a polymer particle with n=2 layers of hydrophilic polyelectrolyte modified on the surface.

[0077] Step 3: After repeating the above steps 1 and 2 for 50 times, polymer particles with n=100 layers of polyelectrolyte multilayer films modified on the surface can be obtained, and the coverage rate of the polyelectrolyte multilayer films on the surface is 100%.

[0078] Step 4: Place the polymer particles modified with n=40 layers of hydrophilic polyelectrolyte multilayer membrane into a double-roll hot pressing machine, at 180°C, a pressure of 50 MPa, maintain a speed of 5 μm / min, and place a 150-mesh polystyrene mesh in the middle, to obtain a polymer film containing hydrophilic channels, in which the contact angle of water on the inner wall of the channel is 10°, the pore size is 50 um, and the thickness is 5 mm.

[0079] Step 5: Place the polymer film containing hydrophilic pores obtained in step 4 into a solution containing 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) and NHS coupling agent for reaction to obtain a polymer porous film with surface carboxylation and biocompatible pores. The contact angle of water on the inner wall of the pores is 8°.

[0080] The hydrophilic porous membrane is used for filtering impurities such as sand, gravel and seaweed in seawater in seawater desalination projects.

[0081] Example 9

[0082] Step 1: 10,000 grams of 50 μm polyurethane (PU)-cycloolefin copolymer (COC) polymer particles are placed in 10 liters of a degassed aqueous solution of 10 g / L cationic electrolyte polydiallyl dimethyl ammonium chloride (PDADMAC) with a molecular weight of 500,000, and allowed to stand for 10 minutes, washed with clean water, and dried. This is recorded as surface modification with n=1 layer of hydrophilic polyelectrolyte surface modified polymer particles.

[0083] Step 2: Place the particles obtained in step 1 into 10L of degassed aqueous solution of polyanionic electrolyte polyacrylic acid (PAA), let stand for 10 minutes, wash with clean water and dry. Recorded as surface modified n=2 layers of hydrophilic polyelectrolyte surface modified polymer particles. Through the above steps, polytetrafluoroethylene particles with a polyelectrolyte multilayer film coverage of 5% can be obtained.

[0084] Step 3: Put the polyurethane (PU)-cycloolefin copolymer (COC) polymer particles modified with n=2 layers of polyelectrolyte multilayer membrane obtained in step 2 into a mold, and keep it at 130°C and a pressure of 20Mpa for 60 minutes to obtain a polymer film containing hydrophilic pores, and a polymer multilayer membrane containing hydrophilic pores, and the contact angle of water on the inner wall of the pores is 30°. The pore size is 50 microns and the thickness is 1 mm.

[0085] Example 10

[0086] Step 1: Put 6000g of polybutylene terephthalate with a particle size of 2μm into the coating pot of the coating machine, and at a rotation speed of 20rpm, spray 10ml of a solution of polycationic electrolyte polyethyleneimine (PEI) with a concentration of 0.5g / L and a molecular weight of 100,000 onto the surface of the polymer particles at a rotation speed of 15rpm, wash with clean water, and then use hot air drying at a temperature of 70°C. After drying, polymer particles modified with a polyelectrolyte multilayer membrane with a layer number n=1 are obtained.

[0087] Step 2: Spray 30 ml of a polyanion electrolyte sodium polyvinyl sulfonate (PVS) solution with a concentration of 0.5 g / L and a molecular weight of 10,000 onto the surface of the polymer particles. Wash with clean water, and then use hot air drying at a temperature of 70°C. After drying, polymer particles modified with polyelectrolyte multilayer films with a layer number n=2 are obtained.

[0088] Step 3: Repeat the process of step 1 and step 2 for 3 times to obtain polybutylene terephthalate polymer particles with n=6 layers of hydrophilic polyelectrolyte multilayer films modified on the surface. The coverage rate of the polyelectrolyte multilayer films on the surface of the particles is 50%.

[0089] Step 4: Using the above-mentioned polybutylene terephthalate particles with n=6 layers of hydrophilic polyelectrolyte multilayer membrane modified on the surface as raw material, at a temperature of 100°C and a pressure of 10 MPa, after maintaining for 60 minutes, a polymer membrane containing hydrophilic channels can be obtained. The pore size is 2 μm, the thickness is 2 mm, and the contact angle of water on the inner wall of the channel is 15°.

[0090] The contact angles in the pores of the porous film measured by the experiment are all less than 30°, proving the hydrophilicity of the pores. The tensile test proves that the mechanical properties of the porous film are basically the same as those of the polymer film not modified by the polyelectrolyte multilayer film.

[0091] In summary, the results of the above embodiments and test examples show that the present invention has achieved the following technical effects:

[0092] 1. The pores of the polymer porous film of the present invention are hydrophilic and can be directly used in related applications in the liquid phase.

[0093] 2. The mechanical properties of the polymer film of the present invention meet the relevant requirements and are comparable to those of porous films prepared from polymer particles of unmodified polyelectrolyte multilayer films, and are superior to the results of hydrophilic modification of the pores of traditional polymer films by physical or chemical methods.

[0094] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the claims of the present application.

Claims

1. A polymer film having hydrophilic pores, characterized in that: The pores are hydrophilic, the contact angle of water on the inner wall of the pores is less than 30 degrees, the diameter of the pores is 50nm-100μm, and the thickness of the polymer film is in the range of 1μm-10mm.

2. The polymer film according to claim 1, characterized in that: The diameter of the pores is 100nm-50μm, and the thickness of the polymer film is 10μm-5mm.

3. A method for preparing a polymer film having hydrophilic pores according to claim 1 or 2, characterized in that: The polymer particles with hydrophilic polyelectrolyte multilayer films modified on the surface are used as raw materials, and a polymer film containing hydrophilic pores is prepared by a hot pressing molding method.

4. The method for preparing a polymer film having hydrophilic pores according to claim 3, characterized in that: The following steps are involved: Step 1: Modify the hydrophilic polyelectrolyte multilayer onto the surface of polymer particles using a layer-by-layer assembly method; Step 2: Using a hot pressing method, the polymer particles modified with the hydrophilic polyelectrolyte multilayer film are prepared into a polymer film containing hydrophilic channels.

5. The preparation method according to claim 4, characterized in that: In step 1, the polymer particle material includes thermoplastic polymers and copolymers thereof and their derivatives, wherein the thermoplastic polymers include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polybutylene terephthalate, polycarbonate, polyphenylene oxide, polyphenylene sulfide, polyoxymethylene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyetheretherketone, polyethersulfone, cycloolefin copolymer, styrene-acrylic resin, styrene-methyl methacrylate, nylon, polyethylene terephthalate, polyphosphate or acrylonitrile-butadiene-styrene or polymethyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer; and / or, in an air environment, the contact angle of a water droplet on the surface of the polymer particle is 60°-120°, and the size of the polymer particle is 50nm-500μm; and / or, in step 1, the coverage of the hydrophilic polyelectrolyte multilayer film on the surface of the polymer particle material is 0-100%; And / or, the number of layers of the hydrophilic polyelectrolyte multilayer membrane is 1 to 100.

6. The preparation method according to claim 4, characterized in that: In step 1, the layer-by-layer assembly method comprises: preparing polyelectrolytes with opposite charges into polyelectrolyte polymer aqueous solution A and polyelectrolyte polymer aqueous solution B respectively, and cyclically coating the polyelectrolyte polymer aqueous solution A and the polyelectrolyte polymer aqueous solution B on the surface of the polymer particle material in sequence to form a hydrophilic polyelectrolyte multilayer film; the polyelectrolytes with opposite charges include polycationic electrolytes and polyanionic electrolytes.

7. The preparation method according to claim 6, characterized in that: The polycation electrolyte comprises one or more of polydiallyldimethylammonium chloride, polyethyleneimine, polyallylamine hydrochloride or chitosan; and / or, the molecular weight of the polycationic electrolyte is 10,000 to 1,000,000; And / or, the polyanion electrolyte comprises one or more of sodium polystyrene sulfonate, sodium polyvinyl sulfonate, polyacrylic acid, polymethacrylic acid, sodium carboxymethyl cellulose, polymethacrylic acid, poly(2-vinylpyridine), poly(4-vinylpyridine), polymaleic acid, polypeptide, protein, DNA or sodium alginate; And / or, the molecular weight of the polyanion electrolyte is 2000 to 1 million; And / or, the concentration of the polyelectrolyte polymer aqueous solution A and / or the polyelectrolyte polymer aqueous solution B is 0.01-20 g / L, and the concentration of the inorganic salt contained is 0-5 mol / L.

8. The preparation method according to claim 4, characterized in that: In step 2, the hot pressing pressure used is 1 MPa to 1000 MPa, the holding time is 1 min to 360 min, and the temperature is 80° C. to 280° C.

9. The preparation method according to claim 4, characterized in that: When preparing a polymer film containing hydrophilic pores, an auxiliary agent is added during the hot pressing process, and the auxiliary agent includes at least one of a polymer material, a steel mesh or an inorganic polymer material.

10. The preparation method according to claim 3, characterized in that: The invention also includes step 3, modifying the polymer film containing hydrophilic channels by chemical or physical methods to obtain a polymer film containing hydrophilic channels with different functions.