A polymer film material, and a method of making and using the same

Abstract

The application belongs to the technical field of filter membrane materials, and particularly relates to a polymer membrane material, a preparation method and application thereof. The polymer membrane material comprises the following mass percentage of raw materials: 10-18% of a film-forming polymer, 0.1-22% of an alkenyl monomer, 0.1-3% of an initiator, 0.1-22% of a coupling agent and 35-89.7% of an organic solvent; the alkenyl monomer comprises an alkenyl hydrophilic monomer and an alkenyl siloxyl monomer. The alkenyl monomer is physically entangled with the film-forming polymer through in-situ polymerization, so that the hydrophilicity and the antifouling property of the polymer membrane material are improved; the coupling agent is pre-embedded in the casting solution as an anchor point for subsequent reaction, and in the phase separation and solidification process, the coupling agent can be used as a uniformly distributed 'network node' to rapidly couple and crosslink through chemical action, so that the covalent force is used as an internal driving force to inhibit segregation, and the hydrophilic modifier which is prone to segregation and dissolution is locked in the polymer membrane, so that the stability is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of filter membrane materials, and particularly relates to a polymer membrane material and a preparation method and application thereof. BACKGROUND

[0002] At present, separation technology based on ultrafiltration membranes is widely applied in the water treatment industry; polyvinyl chloride, polyvinylidene fluoride and polyethersulfone are used as membrane materials of ultrafiltration membranes, and have excellent chemical and thermal stability and good mechanical strength. However, due to the low hydrophilicity of these membrane materials, problems such as low permeation flux, poor selectivity and easy fouling occur in the use process, which seriously limits the application and development of ultrafiltration membranes.

[0003] Therefore, it is necessary to modify the existing polymer membrane material to improve its hydrophilicity; the common modification method at present is surface segregation technology. Surface segregation is a method of adding a hydrophilic additive to the casting solution by blending, and the hydrophilic group will be enriched and segregated on the surface of the film during the film forming process driven by thermodynamics. However, most of the existing hydrophilic additives are water-soluble polymers, which will be precipitated into the coagulation bath to form pores during the exchange of non-solvent during the film forming process, which will significantly reduce the selectivity of the ultrafiltration membrane; in addition, there is a lack of stable chemical bond between the hydrophilic additive and the polymer material, and the hydrophilic additive is easy to precipitate during use, so that the ultrafiltration membrane lacks long-term running stability. Therefore, it is an urgent technical problem to develop a polymer membrane material with high selectivity and stability. SUMMARY

[0004] Therefore, the application provides a polymer membrane material and a preparation method and application thereof, and the polymer membrane material provided by the application has excellent selectivity and stability.

[0005] In order to solve the above technical problems, the application provides a polymer membrane material, which comprises the following mass percentage of preparation raw materials:

[0006] membrane forming polymer 10-18%;

[0007] alkenyl monomer 0.1-22%;

[0008] initiator 0.1-3%;

[0009] coupling agent 0.1-22%;

[0010] organic solvent 35-89.7%;

[0011] The alkenyl monomer comprises an alkenyl hydrophilic monomer and an alkenyl siloxyl monomer.

[0012] Preferably, the mass ratio of the alkenyl hydrophilic monomer and the alkenyl siloxy monomer is 1~9:1~9;

[0013] The alkenyl hydrophilic monomer includes one or more of ethyl vinyl ether, 2-hydroxyethyl methacrylate, N-vinyl formamide, 3-allyloxy-1,2-propanediol, N-vinyl pyrrolidone, glycidyl methacrylate, N-(hydroxymethyl) acrylamide, N-(hydroxyethyl) acrylamide, and hydroxyethyl methacrylate;

[0014] The alkenyl siloxy monomer includes one or more of vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tri(2-methoxyethoxy)silane, and methyl vinyl dimethoxysilane.

[0015] Preferably, the coupling agent includes tetraethyl orthosilicate or triethoxysilane.

[0016] Preferably, the initiator is an oil-soluble azo initiator.

[0017] Preferably, the film-forming polymer includes polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene fluoride, polysulfone, or polyether sulfone.

[0018] The organic solvent includes dimethylformamide, dimethyl sulfoxide, or dimethylacetamide.

[0019] The present application also provides a preparation method of the polymer film material described in the above technical solution, including the following steps:

[0020] Mixing the film-forming polymer, the alkenyl monomer, the initiator, the coupling agent, and the organic solvent to perform in-situ polymerization to obtain a casting solution;

[0021] After film formation of the casting solution, soaking in a coagulation bath to perform solidification to obtain the polymer film material.

[0022] Preferably, the mixing includes the following steps:

[0023] Dissolving the film-forming polymer in the organic solvent to obtain a film-forming polymer solution;

[0024] After dissolving the alkenyl monomer in the film-forming polymer solution, mixing the initiator and the coupling agent to obtain the casting solution.

[0025] Preferably, the temperature of the in-situ polymerization is 50~90℃, and the time is 4~48h.

[0026] Preferably, the coagulation bath includes a sodium hydroxide solution or a hydrochloric acid solution.

[0027] The mass concentration of the coagulation bath is 0.1~20%.

[0028] The temperature of the coagulation bath is 20-70 DEG C.

[0029] The application further provides the application of the polymer membrane material in the technical solution or the polymer membrane material prepared by the preparation method in the technical solution as an ultrafiltration membrane.

[0030] The application provides a polymer membrane material, which comprises the following raw materials in mass percentage: 10-18% of a film-forming polymer, 0.1-22% of an alkenyl monomer, 0.1-3% of an initiator, 0.1-22% of a coupling agent and 35-89.7% of an organic solvent; the alkenyl monomer comprises an alkenyl hydrophilic monomer and an alkenyl siloxy monomer. In the application, the alkenyl monomer is polymerized in situ to form a functional polymer, and the polymer formed by in-situ polymerization and the film-forming polymer are physically entangled, so that the hydrophilicity, antifouling property and stability of the polymer membrane material are improved. Meanwhile, the coupling agent is pre-embedded in the casting solution as an anchor point for subsequent reaction, and can be coupled and crosslinked as a uniformly distributed "network node" through chemical action in the process of phase separation and solidification, so as to lock the hydrophilic modifier which is easy to segregate and dissolve in the polymer membrane by covalent force as an internal driving force for inhibiting segregation, and the selectivity of the polymer membrane material is improved.

[0031] The application further provides a preparation method of the polymer membrane material in the technical solution, which comprises the following steps: mixing the film-forming polymer, the alkenyl monomer, the initiator, the coupling agent and the organic solvent to perform in-situ polymerization and obtain a casting solution; and pre-forming the casting solution and then soaking it in a coagulation bath to perform solidification and obtain the polymer membrane material. In the application, the in-situ polymerization is initiated to cooperate with the synchronous dissolution and entanglement of the film-forming polymer, and the coupling agent is used as a chemical linkage fulcrum in the process of phase separation, so as to effectively control the segregation and slow-release behavior of the modified additive (the polymer generated by in-situ polymerization), firmly "lock" the modified additive in the separation membrane by high-activity coupling chemistry, and realize the synchronous improvement of the permeability, selectivity and persistent hydrophilicity of the ultrafiltration membrane by one-step method. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a schematic diagram of the principle for preparing the polymer membrane material;

[0033] Figure 2 It is a pore size distribution point line graph of the membrane material prepared in Examples 6-9 and Comparative Examples 1-2;

[0034] Figure 3 It is a Fourier infrared spectrum of the membrane material prepared in Example 8 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0035] The application provides a polymer membrane material, which comprises the following raw materials in mass percentage:

[0036] Film forming polymer 10-18%;

[0037] Alkenyl monomer 0.1-22%;

[0038] Initiator 0.1-3%;

[0039] Coupling agent 0.1-22%;

[0040] Organic solvent 35-89.7%;

[0041] The alkenyl monomer includes an alkenyl hydrophilic monomer and an alkenyl siloxy monomer.

[0042] The polymer film material provided by the present application includes 10-18% film forming polymer in mass percentage, which can be 12-16%. As a specific embodiment of the present application, the film forming polymer includes polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene fluoride, polysulfone or polyethersulfone.

[0043] The polymer film material provided by the present application includes 0.1-22% alkenyl monomer in mass percentage, which can be 3-12%, 6-10%, or 7-8%. As a specific embodiment of the present application, the alkenyl monomer includes an alkenyl hydrophilic monomer and an alkenyl siloxy monomer, and the mass ratio of the alkenyl hydrophilic monomer to the alkenyl siloxy monomer can be 1-9:1-9, specifically 1:1, 2:1, 3:1, 2:8, 1:9 or 9:1. As a specific embodiment of the present application, the alkenyl hydrophilic monomer can include one or more of ethyl vinyl ether, 2-hydroxyethyl methacrylate, N-vinyl formamide, 3-allyloxy-1,2-propanediol, N-vinyl pyrrolidone, glycidyl methacrylate, N-(hydroxymethyl) acrylamide, N-(hydroxyethyl) acrylamide and hydroxyethyl methacrylate; specifically glycidyl methacrylate, N-vinyl pyrrolidone, ethyl vinyl ether, 3-allyloxy-1,2-propanediol or 2-hydroxyethyl methacrylate. As a specific embodiment of the present application, the alkenyl siloxy monomer can include one or more of vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tri(2-methoxyethoxy)silane and methyl vinyl dimethoxysilane, specifically vinyl trimethoxysilane. In the present application, the alkenyl siloxy monomer contains a high-activity coupling group siloxy group; the alkenyl part in the alkenyl siloxy monomer can be subjected to in-situ radical polymerization with the alkenyl hydrophilic monomer; and the siloxy functional group in the alkenyl siloxy monomer can be subjected to self-polymerization or cross-linking with the coupling agent.

[0044] The polymer film material provided by the application contains 0.1-3% initiator in terms of mass percentage, which can be 0.5-2.2%, and can also be 1-2%. As a specific embodiment of the application, the initiator can be an oil-soluble azo initiator, which can be azobisisobutyronitrile (AIBN).

[0045] The polymer film material provided by the application contains 0.1-22% coupling agent in terms of mass percentage, which can be 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20% or 22%. As a specific embodiment of the application, the coupling agent can contain tetraethyl orthosilicate (TEOS) or triethoxysilane. In the application, the coupling agent contains two or more groups that can be crosslinked with the high-activity coupling groups in the alkenyl siloxyl monomer (siloxyl groups).

[0046] The polymer film material provided by the application contains 35-89.7% organic solvent in terms of mass percentage, which can be 40-80%, and can also be 67-75%. As a specific embodiment of the application, the organic solvent can include dimethylformamide, dimethyl sulfoxide or dimethylacetamide (DMAc).

[0047] As a specific embodiment of the application, the thickness of the polymer film material can be 100-350 μm, and can also be 200-300 μm; the pore size of the polymer film material can be 20-100 nm, and can also be 24-40 nm; the pure water permeation flux of the polymer film material can be 50-2000 L·m -2 ·h -1 ·bar -1 , and can also be 100-410 L·m -2 ·h -1 ·bar -1 ； The rejection rate of the polymer film material to 1.0 g / L bovine serum albumin is more than 90%; the surface water contact angle of the polymer film material is <90°, showing hydrophilicity.

[0048] The application also provides a preparation method of the polymer film material described in the above technical solution, which comprises the following steps:

[0049] The film-forming polymer, alkenyl monomer, initiator, coupling agent and organic solvent are mixed to perform in-situ polymerization to obtain a casting solution;

[0050] The casting solution is pre-formed into a film and then soaked in a coagulation bath to perform solidification, so as to obtain the polymer film material.

[0051] The application mixes film-forming polymer, alkenyl monomer, initiator, coupling agent and organic solvent to carry out in-situ polymerization to obtain casting solution. As a specific embodiment of the application, the mixing can include the following steps:

[0052] The film-forming polymer is first dissolved in the organic solvent to obtain a film-forming polymer solution.

[0053] The alkenyl monomer is second dissolved in the film-forming polymer solution and then mixed with the initiator and the coupling agent to obtain the casting solution.

[0054] The film-forming polymer is first dissolved in the organic solvent to obtain a film-forming polymer solution. As a specific embodiment of the application, the film-forming polymer can be dried before the dissolving; the water content of the film-forming polymer after the drying can be 0.1% or less. As a specific embodiment of the application, the first dissolving can be carried out under stirring; the stirring temperature can be 50-90°C, or 60-80°C; the stirring speed can be 200-400r / min, or 300-350r / min; and the stirring time can be 4-48h, or 10-40h, or 20-30h.

[0055] After obtaining the film-forming polymer solution, the alkenyl monomer is second dissolved in the film-forming polymer solution and then mixed with the initiator and the coupling agent to obtain the casting solution. As a specific embodiment of the application, the second dissolving can be carried out under stirring; the stirring temperature can be 50-90°C, or 60-80°C; the stirring speed can be 200-400r / min, or 300-350r / min; and the stirring time can be 4-48h, or 5-40h, or 10-15h. As a specific embodiment of the application, the second dissolving can be carried out under a protective atmosphere, which can be a nitrogen atmosphere.

[0056] As a specific embodiment of the application, the first mixing can be carried out under stirring; the stirring temperature can be 50-90°C, or 60-80°C; the stirring speed can be 200-400r / min, or 300-350r / min; and the application has no special requirement for the stirring time as long as the mixing is uniform. As a specific embodiment of the application, the first mixing can be carried out under a protective atmosphere, which can be a nitrogen atmosphere.

[0057] As a specific embodiment of the present application, the temperature of the in-situ polymerization can be 50-90℃, and can be specifically 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃ or 90℃; the time of the in-situ polymerization can be 4-48h, and can be specifically 5h, 10h, 15h, 20h, 25h, 30h, 35h, 40h or 45h. As a specific embodiment of the present application, the in-situ polymerization can be carried out under a protective atmosphere, which can be a nitrogen atmosphere.

[0058] After obtaining the casting solution, the present application preforms the casting solution and then soaks it in a coagulation bath for solidification to obtain the polymer film material. As a specific embodiment of the present application, the preforming can be pre-evaporation after blade coating the casting solution on the surface of a substrate; the substrate can be a glass plate; the pre-evaporation can be placing the product after blade coating in air for 20-35s.

[0059] As a specific embodiment of the present application, the coagulation bath can include a sodium hydroxide solution or a hydrochloric acid solution; the mass concentration of the coagulation bath can be 0.1-20%, and can also be 1-15%, and further can be 5-10%; the temperature of the coagulation bath can be 20-70℃, and can also be 25-65℃, and further can be 30-60℃; the time of the soaking can be 10-60min, and can also be 20-50min, and further can be 30-40min.

[0060] As a specific embodiment of the present application, the solidification can further include drying the film material obtained after the solidification to obtain the polymer film material; the temperature of the drying can be 30-50℃, and can also be 35-40℃; the time of the drying can be 40-50h, and can also be 45-48h.

[0061] The schematic diagram of the principle of preparing the polymer film material of the present application is as shown in Figure 1The in-situ polymerization is shown in detail, specifically, dissolving synchronous in-situ polymerization: the film-forming polymer, alkenyl hydrophilic monomer, alkenyl siloxyl monomer, coupling agent, initiator and organic solvent are mixed and polymerization is initiated, the newly generated copolymer of the alkenyl hydrophilic monomer and the alkenyl siloxyl monomer is intertwined with the long chain of the film-forming polymer, forming a uniform and compatible casting solution; at the same time, the coupling agent as an anchor point for subsequent reactions is dissolved synchronously and uniformly distributed in the casting solution, that is, dissolving synchronous in-situ polymerization. High-activity coupling synergizes film formation: after obtaining the uniform casting solution, a non-solvent is used to induce phase separation to prepare an ultrafiltration membrane, the non-solvent can quickly induce coupling combination of high-activity sites in the casting solution, and the coupling agent is used as a connecting branch point to rapidly and stably combine the in-situ polymer chain segments with each other through chemical bonds, and a regular polymer network structure is formed by coupling combination (cross-linking combination of the siloxyl groups in the coupling agent and the in-situ polymer) in the phase separation and film formation process, the polymer long chain movement is constrained, and a uniform ultrafiltration membrane with a high efficiency is constructed, that is, high-activity coupling synergizes film formation.

[0062] The small molecule coupling agent is dissolved in the casting solution in advance, the coupling agent is uniformly distributed in the casting solution, and until the process of phase separation, under the induction of the non-solvent, the "pre-embedded" small molecule coupling agent is used as a branch point for constructing a polymer cross-linking network, and the surface segregation behavior is regulated in a chemical bond linkage manner, the "internal driving force" from the inside of the separation membrane matrix facilitates the more regular distribution of the additive in the polymer membrane, so that the random phase separation process is constrained and regularly arranged at a micro level, that is, high-activity coupling synergizes phase separation to construct a separation membrane, and the film formation process is regulated.

[0063] The preparation method provided by the application has high reaction efficiency, mild conditions, reduces the time cost of additive synthesis, is controllable in the reaction process, and can finely regulate the performance of the polymer membrane material; the flexible selection of the alkenyl monomer can bring rich active reaction sites to the finished ultrafiltration membrane, and the subsequent post-modification in the specific application field is facilitated.

[0064] The application realizes preparation and modification of hydrophilic ultrafiltration membranes by one-step method, not only completes in-situ preparation of functionalization modifier, but also realizes simple preparation of high-selectivity (R BSA > 94%) ultrafiltration membranes by coupling agent regulation of precipitation behavior of the modifier.

[0065] The application further provides application of the polymer membrane material prepared by the preparation method as an ultrafiltration membrane.

[0066] In order to further illustrate the application, the technical solutions provided by the application are described in detail below in combination with examples, but they should not be understood as limiting the protection scope of the application.

[0067] Example 1

[0068] The film-forming polymer is polyvinylidene fluoride, the organic solvent is dimethylacetamide (DMAc), the alkenyl hydrophilic monomer is glycidyl methacrylate, the alkenyl siloxy monomer is vinyl trimethoxysilane, the initiator is azobisisobutyronitrile (AIBN), and the coupling agent is tetraethyl orthosilicate (TEOS).

[0069] S1, 16.0wt% dry polyvinylidene fluoride (8g, water content less than 0.1%) was stirred and dissolved in 75.8wt% DMAc (37.9g), the stirring temperature was 60℃, the stirring time was 4h, and the stirring speed was 300r / min, to obtain a uniformly dissolved film-forming polymer solution.

[0070] S2, 6wt% alkenyl monomer glycidyl methacrylate (1.5g) and vinyl trimethoxysilane (1.5g) were dissolved in the film-forming polymer solution prepared in step S1 at a mass ratio of 1:1, and after stirring and dissolving under N2 atmosphere (stirring temperature was 60℃, stirring time was 5h, and stirring speed was 300r / min), 1wt% (0.5g) AIBN and 1.2wt% (0.6g) TEOS were added, and after stirring uniformly at 60℃ and 300r / min, in-situ polymerization was carried out at 80℃ under N2 atmosphere for 20h, to obtain a casting solution.

[0071] S3, the casting solution obtained in step S2 was coated on a dry glass plate using a 250 pm doctor blade, pre-evaporated in air for 30 s, and then phase separated in a coagulation bath of hydrochloric acid solution with a pH value of 3 at room temperature (25 °C) (immersion time was 10 min). After complete solidification, the obtained ultrafiltration membrane was transferred to deionized water for storage. Part of the ultrafiltration membrane was vacuum dried in an oven at 40 °C for 48 h to obtain a polymer membrane material.

[0072] Example 2

[0073] The film-forming polymer was polyvinylidene fluoride, the organic solvent was dimethylacetamide (DMAc), the alkenyl hydrophilic monomer was N-vinylpyrrolidone, the alkenyl siloxy monomer was vinyltrimethoxysilane, the initiator was azobisisobutyronitrile (AIBN), and the coupling agent was tetraethyl orthosilicate (TEOS). The following steps were used for preparation:

[0074] S1, 16 wt% dry polyvinylidene fluoride (8 g, water content was less than 0.1%) was dissolved in 71 wt% DMAc (35.5 g) by stirring at a temperature of 60 °C for 4 h at a stirring speed of 300 r / min to obtain a uniformly dissolved film-forming polymer solution.

[0075] S2, 10 wt% alkenyl monomers N-vinylpyrrolidone (3.33 g) and vinyltrimethoxysilane (1.67 g) were dissolved in the film-forming polymer solution prepared in step S1 at a mass ratio of 2:1 under N2 atmosphere by stirring at a temperature of 60 °C for 5 h at a stirring speed of 300 r / min. Then, 1 wt% (0.5 g) AIBN and 2 wt% (1 g) TEOS were added, and the mixture was stirred uniformly at 60 °C and 300 r / min. After that, in-situ polymerization was carried out at 80 °C under N2 atmosphere for 20 h to obtain a casting solution.

[0076] S3, the casting solution obtained in step S2 was coated on a dry glass plate using a 250 pm doctor blade, pre-evaporated in air for 30 s, and then phase separated in a coagulation bath of hydrochloric acid solution with a pH value of 3 at room temperature (25 °C) (immersion time was 10 min). After complete solidification, the obtained ultrafiltration membrane was transferred to deionized water for storage. Part of the ultrafiltration membrane was vacuum dried in an oven at 40 °C for 48 h to obtain a polymer membrane material.

[0077] Example 3

[0078] The film-forming polymer is polyvinylidene fluoride, the organic solvent is dimethylacetamide (DMAc), the alkenyl hydrophilic monomer is ethyl vinyl ether, the alkenyl siloxy monomer is vinyl trimethoxysilane, the initiator is azobisisobutyronitrile (AIBN), and the coupling agent is tetraethyl orthosilicate (TEOS). The following steps are used for preparation:

[0079] S1, 16wt% dry polyvinylidene fluoride (8g, water content less than 0.1%) is stirred and dissolved in 71.8wt% DMAc (35.9g), the stirring temperature is 60°C, the stirring time is 4h, and the stirring speed is 300r / min, to obtain a uniformly dissolved film-forming polymer solution.

[0080] S2, 8wt% alkenyl monomer ethyl vinyl ether (3g) and vinyl trimethoxysilane (1g) are dissolved in the film-forming polymer solution prepared in step S1 at a mass ratio of 3:1, and after stirring and dissolving under N2 atmosphere (stirring temperature is 60°C, stirring time is 5h, and stirring speed is 300r / min), 1wt% (0.5g) AIBN and 3.2wt% (1.6g) TEOS are added, and after stirring uniformly at 60°C and 300r / min, in-situ polymerization is carried out at 80°C under N2 atmosphere for 20h, to obtain a casting solution.

[0081] S3, the casting solution obtained in step S2 is coated on a dry glass plate using a 250μm doctor blade, pre-evaporated in air for 30s, phase-separated in a coagulation bath of deionized water with pH value of 7 at room temperature (25°C), and after complete solidification, the obtained ultrafiltration membrane is transferred to deionized water for storage; part of the ultrafiltration membrane is vacuum dried in an oven at 40°C for 48h, to obtain a polymer membrane material.

[0082] Example 4

[0083] The film-forming polymer is polyvinylidene fluoride, the organic solvent is dimethylacetamide (DMAc), the alkenyl hydrophilic monomer is 3-allyloxy-1,2-propanediol, the alkenyl siloxy monomer is vinyl trimethoxysilane, the initiator is azobisisobutyronitrile (AIBN), and the coupling agent is tetraethyl orthosilicate (TEOS). The following steps are used for preparation:

[0084] S1, 16wt% dry polyvinylidene fluoride (8g, water content less than 0.1%) is stirred and dissolved in 65wt% DMAc (32.5g), the stirring temperature is 60°C, the stirring time is 4h, and the stirring speed is 300r / min, to obtain a uniformly dissolved film-forming polymer solution.

[0085] S2, 12wt% of alkenyl monomer 3-allyloxy-1,2-propanediol (4g) and vinyl trimethoxysilane (2g) were dissolved in the film polymer material solution prepared in step S1 at a mass ratio of 2:1, and after stirring and dissolving under N2 atmosphere (stirring temperature was 60°C, stirring time was 5h, stirring speed was 300r / min), 1wt% (0.5g) of AIBN and 6wt% (3g) of TEOS were added, and after stirring uniformly at 60°C, 300r / min, in-situ polymerization reaction was carried out at 80°C under N2 atmosphere for 20h, to obtain a casting solution.

[0086] S3, the casting solution obtained in step S2 was coated on a dry glass plate using a 250μm doctor blade, and after pre-evaporation in air for 30s, phase separation was carried out in a coagulation bath of sodium hydroxide solution with pH value of 11 at room temperature (25°C), and after complete solidification, the obtained ultrafiltration membrane was transferred to deionized water for storage; part of the ultrafiltration membrane was vacuum dried in an oven at 40°C for 48h, to obtain a polymer film material.

[0087] Example 5

[0088] The film-forming polymer was polyvinylidene fluoride, the organic solvent was dimethylacetamide (DMAc), the alkenyl hydrophilic monomer was 2-hydroxyethyl methacrylate, the alkenyl siloxy monomer was vinyl trimethoxysilane, the initiator was azobisisobutyronitrile (AIBN), and the coupling agent was tetraethyl orthosilicate (TEOS), which were prepared by the following steps:

[0089] S1, 16wt% of dry polyvinylidene fluoride (8g, water content was less than 0.1%) was stirred and dissolved in 74.6wt% of DMAc (37.3g), the stirring temperature was 60°C, the stirring time was 4h, and the stirring speed was 300r / min, to obtain a uniformly dissolved film-forming polymer solution.

[0090] S2, 7wt% of alkenyl monomer 2-hydroxyethyl methacrylate (2.33g) and vinyl trimethoxysilane (1.17g) were dissolved in the film polymer material solution prepared in step S1 at a mass ratio of 2:1, and after stirring and dissolving under N2 atmosphere (stirring temperature was 60°C, stirring time was 5h, stirring speed was 300r / min), 1wt% (0.5g) of AIBN and 1.4wt% (0.7g) of TEOS were added, and after stirring uniformly at 60°C, 300r / min, in-situ polymerization reaction was carried out at 80°C under N2 atmosphere for 20h, to obtain a casting solution.

[0091] S3, the casting solution obtained in step S2 was coated on a dry glass plate using a 250 pm doctor blade, pre-evaporated in air for 30 s, and then phase separated in a sodium hydroxide solution with a pH value of 10 at room temperature (25 °C). After complete solidification, the obtained ultrafiltration membrane was transferred to deionized water for storage. Part of the ultrafiltration membrane was vacuum dried in an oven at 40 °C for 48 h to obtain a polymer membrane material.

[0092] Example 6

[0093] The film-forming polymer was polyvinylidene fluoride, the organic solvent was dimethylacetamide (DMAc), the alkenyl hydrophilic monomer was 2-hydroxyethyl methacrylate, the alkenyl siloxy monomer was vinyltrimethoxysilane, the initiator was azobisisobutyronitrile (AIBN), and the coupling agent was tetraethyl orthosilicate (TEOS). The following steps were used for preparation:

[0094] S1, 16 wt% dry polyvinylidene fluoride (8 g, with a water content of less than 0.1%) was stirred and dissolved in 78.5 wt% DMAc (39.25 g) at a temperature of 60 °C for 4 h at a stirring speed of 300 r / min to obtain a uniformly dissolved film-forming polymer solution.

[0095] S2, 3 wt% of the alkenyl monomers 2-hydroxyethyl methacrylate (1 g) and vinyltrimethoxysilane (0.5 g) were dissolved in the film-forming polymer solution prepared in step S1 at a mass ratio of 2:1 under N2 atmosphere, and then stirred and dissolved (at a temperature of 60 °C for 5 h at a stirring speed of 300 r / min). After adding 1 wt% (0.5 g) of AIBN and 1.5 wt% (0.75 g) of TEOS, the mixture was stirred uniformly at 60 °C and 300 r / min, and then in-situ polymerized at 80 °C under N2 atmosphere for 20 h to obtain a casting solution.

[0096] S3, the casting solution obtained in step S2 was coated on a dry glass plate using a 250 pm doctor blade, pre-evaporated in air for 30 s, and then phase separated in a sodium hydroxide solution with a pH value of 10 at room temperature (25 °C). After complete solidification, the obtained ultrafiltration membrane was transferred to deionized water for storage. Part of the ultrafiltration membrane was vacuum dried in an oven at 40 °C for 48 h to obtain a polymer membrane material, which was denoted as M2.

[0097] Example 7

[0098] The polymer membrane material was prepared according to the method of Example 6, except that the mass percentage of polyvinylidene fluoride was 16 wt%, the weight percentage of DMAc was 74 wt%, the addition amount of 2-hydroxyethyl methacrylate was 2 g, the addition amount of vinyl trimethoxysilane was 1 g, the total mass percentage of alkenyl monomers was 6 wt%, the total mass percentage of TEOS was 3 wt%, and the mass percentage of AIBN was 1 wt%. The prepared polymer membrane material was denoted as M3.

[0099] Example 8

[0100] The polymer membrane material was prepared according to the method of Example 6, except that the mass percentage of polyvinylidene fluoride was 16 wt%, the weight percentage of DMAc was 69.5 wt%, the addition amount of 2-hydroxyethyl methacrylate was 3 g, the addition amount of vinyl trimethoxysilane was 1.5 g, the total mass percentage of alkenyl monomers was 9 wt%, the total mass percentage of TEOS was 4.5 wt%, and the mass percentage of AIBN was 1 wt%. The prepared polymer membrane material was denoted as M4.

[0101] Example 9

[0102] The polymer membrane material was prepared according to the method of Example 6, except that the mass percentage of polyvinylidene fluoride was 16 wt%, the weight percentage of DMAc was 65 wt%, the total mass percentage of 2-hydroxyethyl methacrylate (4 g) and vinyl trimethoxysilane (2 g) was 12 wt%, the mass percentage of TEOS was 6 wt%, and the mass percentage of AIBN was 1 wt%. The prepared polymer membrane material was denoted as M5.

[0103] Comparative Example 1 (without alkenyl monomer, initiator, coupling agent)

[0104] S1, 8 g of dry polyvinylidene fluoride (water content less than 0.1%) was stirred and dissolved in 42 g of DMAc, the stirring temperature was 60°C, the stirring time was 4 h, and the stirring speed was 300 r / min, to obtain a uniformly dissolved casting solution.

[0105] S2, the casting solution obtained in step S1 was coated on a dry glass plate using a 250 μm doctor blade, pre-evaporated in air for 30 s, and then phase-separated in a coagulation bath of deionized water with a pH value of 7 at room temperature (25°C). After complete solidification, the obtained ultrafiltration membrane was transferred to deionized water for storage. Part of the ultrafiltration membrane was vacuum dried in an oven at 40°C for 48 h to obtain a membrane material, denoted as M0.

[0106] Comparative Example 2 (without coupling agent)

[0107] S1, 8 g of dry polyvinylidene fluoride (moisture content less than 0.1%) was stirred and dissolved in 37 g of DMAc, the stirring temperature was 60°C, the stirring time was 4 h, the stirring speed was 300 r / min, and a uniformly dissolved film-forming polymer solution was obtained.

[0108] S2, the alkenyl monomer 2-hydroxyethyl methacrylate (3 g) and vinyltrimethoxysilane (1.5 g) were dissolved in the film-forming polymer solution prepared in step S1 at a mass ratio of 2:1, and after stirring and dissolving under N2 atmosphere (stirring temperature was 60°C, stirring time was 5 h, stirring speed was 300 r / min), 0.5 g of AIBN was added, and after stirring uniformly at 60°C and 300 r / min, in-situ polymerization was carried out at 80°C under N2 atmosphere for 20 h, and a casting solution was obtained.

[0109] S3, the casting solution obtained in step S2 was coated on a dry glass plate using a 250 μm doctor blade, pre-evaporated in air for 30 s, and then phase-separated in a coagulation bath of deionized water with a pH value of 7 at room temperature (25°C), and after complete solidification, the obtained ultrafiltration membrane was transferred to deionized water for storage; part of the ultrafiltration membrane was vacuum dried in an oven at 40°C for 48 h, and a polymer film material was obtained, denoted as M1.

[0110] The membrane materials prepared in Examples 6-9 and Comparative Examples 1-2 were subjected to pore size distribution detection, and a pore size distribution point line graph was drawn as shown in Figure 2 ; and the pore sizes are listed in Table 1.

[0111] The membrane materials prepared in Example 8 and Comparative Examples 1-2 were subjected to infrared detection, and a Fourier infrared spectrum was obtained as shown in Figure 3 .

[0112] The flux and bovine serum protein rejection rate of the membrane materials prepared in Examples 1-9 and Comparative Examples 1-2 were detected according to GB / T 32360-2015, ultrafiltration membrane test method, and the results are shown in Table 1; the water contact angle of the membrane materials prepared in Examples 1-9 and Comparative Examples 1-2 and the membrane materials after being soaked in deionized water for 200 h were detected using a full-automatic contact angle instrument, and the results are shown in Table 1.

[0113] Table 1 Properties of the membrane materials prepared in Examples 1-9 and Comparative Examples 1-2

[0114]

[0115] In combination with Table 1 and Figure 2It can be seen that the pore size distribution of M1 to M5 is narrowed with the increase of the amount of coupling agent, but M1, due to the absence of coupling agent, the in-situ polymerization of the generated copolymer additive exists in the phase separation of segregation and precipitation phenomenon, showing Figure 2 The range of pore size distribution is greatly increased, while M2 to M5, due to the presence of pre-loaded coupling agent, effectively prevents the precipitation of copolymer during the phase separation process, and with the increase of its amount, the polymer crosslinked network is constantly improved, and the uniformity of the pore size distribution is constantly improved, which shows that this high activity coupling induced phase separation method can provide high selectivity membrane with uniform pore size.

[0116] Figure 3 1750cm -1 The characteristic absorption peak representing the carbonyl group is higher in intensity after the addition of coupling agent, which more fully illustrates that under the condition of constant amount of in-situ polymerization copolymer additive, the pre-loading of coupling agent can anchor the copolymer through chemical bonding, limit its precipitation behavior, so that the ultrafiltration membrane remains high selectivity while being hydrophilically modified.

[0117] From the performance parameters of pure water flux, bovine serum albumin rejection rate and water contact angle in Table 1, it can be seen that the covalent force between the coupling agent and the in-situ polymerization copolymer additive can stably limit it in the separation membrane, and in the process of phase separation, it realizes the persistent improvement of hydrophilic modification while effectively inhibiting the generation of large pores on the surface of the separation membrane, and the present application successfully obtains a high selectivity hydrophilic ultrafiltration membrane.

[0118] Although the above embodiment describes the present application in detail, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained under the premise of no creativity according to the present embodiment, which all belong to the protection scope of the present application.

Claims

1. A polymeric film material, characterized by, Prepared from the following raw materials with the following mass percentage: Film forming polymer 10~18%; Alkenyl monomer 0.1~22%; Initiator 0.1~3%; Coupling agent 0.1~22%; Organic solvent 35~89.7%; The film forming polymer includes polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene fluoride, polysulfone or polyethersulfone; The alkenyl monomer includes alkenyl hydrophilic monomer and alkenyl siloxy monomer; The coupling agent is tetraethyl orthosilicate or triethoxysilane; The pore size of the polymer membrane material is 24~40nm; The preparation method of the polymer membrane material includes the following steps: Mixing the film forming polymer, alkenyl monomer, initiator, coupling agent and organic solvent to conduct in-situ polymerization to obtain a casting solution; Preforming the casting solution and then immersing it in a coagulation bath to conduct solidification to obtain the polymer membrane material; the coagulation bath includes sodium hydroxide solution or hydrochloric acid solution; the mass concentration of the coagulation bath is 0.1~20%; the temperature of the coagulation bath is 20~25℃.

2. The polymeric film material of claim 1, wherein, The mass ratio of the alkenyl hydrophilic monomer and the alkenyl siloxy monomer is 1~9:1~9; The alkenyl hydrophilic monomer includes one or more of ethyl vinyl ether, 2-hydroxyethyl methacrylate, N-vinyl formamide, 3-allyloxy-1,2-propanediol, N-vinyl pyrrolidone, glycidyl methacrylate, N-(hydroxymethyl) acrylamide and N-(hydroxyethyl) acrylamide; The alkenyl siloxy monomer includes one or more of vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tri(2-methoxyethoxy)silane and methyl vinyl dimethoxysilane.

3. The polymeric film material of claim 1, wherein, The initiator is an oil-soluble azo initiator.

4. The polymeric film material of claim 1, wherein, The organic solvent includes dimethylformamide, dimethyl sulfoxide or dimethylacetamide.

5. A method of producing the polymer film material according to any one of claims 1 to 4, characterized by, Including the following steps: Mixing the film forming polymer, alkenyl monomer, initiator, coupling agent and organic solvent to conduct in-situ polymerization to obtain a casting solution; Preforming the casting solution and then immersing it in a coagulation bath to conduct solidification to obtain the polymer membrane material; the coagulation bath includes sodium hydroxide solution or hydrochloric acid solution; the mass concentration of the coagulation bath is 0.1~20%; the temperature of the coagulation bath is 20~25℃.

6. The method of claim 5, wherein the polymer film material is prepared by a process comprising: The mixing includes the following steps: Dissolving the film forming polymer in the organic solvent to obtain a film forming polymer solution; Dissolving the alkenyl monomer in the film forming polymer solution and then mixing the initiator and the coupling agent to obtain the casting solution.

7. The method for preparing the polymer film material according to claim 5 or 6, characterized in that, The temperature of the in-situ polymerization is 50~90℃ and the time is 4~48h.

8. Application of the polymer membrane material of any one of claims 1~4 or prepared by the preparation method of any one of claims 5~7 as an ultrafiltration membrane.

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