CN107261863B - Preparation method of anti-pollution polyvinyl chloride film - Google Patents
Preparation method of anti-pollution polyvinyl chloride film Download PDFInfo
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- CN107261863B CN107261863B CN201710480968.2A CN201710480968A CN107261863B CN 107261863 B CN107261863 B CN 107261863B CN 201710480968 A CN201710480968 A CN 201710480968A CN 107261863 B CN107261863 B CN 107261863B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/30—Polyalkenyl halides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0006—Organic membrane manufacture by chemical reactions
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/36—Hydrophilic membranes
Abstract
A preparation method of an anti-pollution polyvinyl chloride film comprises the following steps: (1) taking polyvinyl chloride (PVC) as a membrane material and Vinyl Caprolactam (VCL) as a monomer, and synthesizing an amphiphilic copolymer PVC-g-PVCL by Atom Transfer Radical Polymerization (ATRP); (2) the synthetic PVC-g-PVCL is taken as a film forming material, and a separation film is prepared by an immersion phase inversion method. The invention firstly utilizes the Vinyl Caprolactam (VCL) which has hydrophilicity and has exclusion performance on protein adsorption to carry out copolymerization modification on the PVC membrane to obtain the PVC separation membrane with good pollution resistance. The hydrophilicity of the prepared modified membrane is superior to that of a pure PVC membrane, and the adsorbed protein on the surface of the membrane is obviously reduced. The hydrophilic membrane can be further developed and utilized as a sewage treatment separation membrane.
Description
Technical Field
The invention belongs to a preparation method of an anti-pollution polyvinyl chloride membrane, and particularly relates to a preparation technology of a polyvinyl chloride membrane separation membrane with good anti-pollution performance.
Background
Polyvinyl chloride (PVC) is a product obtained by polymerizing vinyl chloride monomer, has the advantages of low price, high chemical and thermal stability, etc., and is widely used for manufacturing plastic products. In recent years, PVC can be used for preparing microfiltration, ultrafiltration membranes and the like due to good film-forming performance. Is applied to the fields of sewage treatment, petrochemical industry and the like. However, the PVC has lower surface energy and the nature of hydrophobicity makes the PVC film easily absorb organic substances to cause film pollution. Membrane fouling increases the energy loss during membrane separation, and reduces the membrane separation efficiency and the service performance of the membrane material.
The optimized design of the membrane component, the reduction of the pollution of the membrane by utilizing the action of an external field, the cleaning of the membrane, the design of the anti-pollution membrane and the like are all methods for inhibiting the membrane pollution phenomenon. The principle of the hydrophilic modification of the separation membrane material is that a hydrophilic material with high surface energy is introduced into the membrane material to organize the adsorption and deposition of pollutants on the surface of the membrane. The hydrophilic modification method of the PVC separation membrane comprises surface modification, blending hybridization, copolymerization modification and the like. The surface modification is mainly to improve the pollution resistance by chemically grafting or coating a hydrophilic material on the surface of the PVC base membrane, and the method has the disadvantage that the permeability of the separation membrane is reduced when the thickness of the grafting layer or the coating layer is too high. The hybrid modification is to introduce hydrophilic inorganic nano particles in the film forming process, and the method is simple to operate, but not only enables the nano particles to be easy to agglomerate in the film material simply through blending modification, but also enables the nano particles to be easy to separate in practical application, so that the anti-pollution performance of the separation film is unstable. PVC copolymerization modification is that after PVC and hydrophilic material are polymerized, the obtained copolymer is used for preparing a separation membrane by a phase inversion method. Compared with surface modification and blending hybridization, PVC copolymerization modification has various advantages. Firstly, the hydrophilic material is combined with PVC through chemical bonds, so that the hydrophilic performance of the separation membrane is stable; secondly, in the film forming process, the anti-pollution films with different separation performances can be prepared by controlling the film forming conditions.
Polyvinyl caprolactam (PVCL) is a polymeric material that is homopolymerized with vinyl caprolactam and can be used to prepare temperature sensitive devices. Meanwhile, the PVCL has good hydrophilic performance and shows potential adhesion rejection performance to organic matters, the PVCL is used for hydrophilic modification of the PVC membrane, and the traditional hydrophilic modification method of the PVC membrane is not enough, so that the separation membrane with good anti-pollution performance is obtained.
Disclosure of Invention
The invention aims to provide a preparation method of an anti-pollution polyvinyl chloride membrane, aiming at the defects of the existing hydrophilic modification method of a PVC membrane, Vinyl Caprolactam (VCL) is adopted to modify a copolymer of PVC, and a flat separation membrane with good anti-pollution performance is obtained.
The technical scheme is as follows: a preparation method of an anti-pollution polyvinyl chloride film comprises the following steps: (1) PVC is used as a membrane material, VCL is used as a monomer, cuprous chloride (CuCl) is used as a catalyst, pentamethyl dipropylene triamine (PMDETA) is used as a ligand, and an amphiphilic copolymer PVC-g-PVCL is synthesized by atom transfer radical polymerization; (2) the separation membrane is prepared by using a PVC-g-PVCL copolymer as a membrane material and polyethylene glycol (PEG) as an additive through an immersion phase inversion method.
The PVC-g-PVCL copolymer in the step (1) is synthesized by the following method: weighing dry PVC powder, putting the powder into N-methyl pyrrolidone (NMP), stirring at 70 ℃ to completely dissolve the PVC powder, and cooling the solution to room temperature; charging nitrogen for 10min, and adding catalyst cuprous chloride (CuCl), ligand pentamethyl dipropylene triamine (PMDETA) and monomer VCL; pumping out the gas in the reaction liquid by a vacuum pump, sealing the reactor, carrying out reaction at 70 ℃, precipitating by absolute ethyl alcohol and pure water, washing and drying to obtain the product.
The concentration of PVC powder in the reaction liquid is 30-90 g/L;
the concentration of a monomer VCL in the reaction liquid is 0.1-1 mol/L;
the concentration of the catalyst CuCl in the reaction liquid is 0.01-0.03 mol/L;
the concentration of ligand PMDETA in the reaction solution is 0.01-0.03 mol/L;
the reaction is carried out for 6-24 h.
The specific steps for preparing the PVC-g-PVCL separation membrane in the step (2) are as follows: weighing PVC-g-PVCL copolymer and polyethylene glycol (PEG), placing the PVC-g-PVCL copolymer and the PEG in an NMP solvent, stirring at 60 ℃ to completely dissolve, standing and defoaming the membrane casting solution for 24 hours, and scraping a separation membrane by using a scraper; and (3) rapidly immersing the primary membrane in a coagulant, taking out a membrane sample after the membrane is completely solidified, washing with pure water, and storing in the pure water for later use.
The mass percentage of the PVC-g-PVCL copolymer is 10-15% of the total weight of the membrane casting solution;
the mass percentage of the added PEG accounts for 2-6% of the total weight of the casting solution; the average molecular weight of PEG is 8000-20000 g/mol;
the size of the film scraping knife used for film preparation is 100-300 mu m;
the coagulant used for preparing the membrane is pure water, and the temperature is 25 ℃.
The prepared separation membrane is a flat membrane;
advantageous effects
The invention firstly utilizes the Vinyl Caprolactam (VCL) which has hydrophilicity and has exclusion performance on protein adsorption to carry out copolymerization modification on the PVC membrane to obtain the PVC separation membrane with good pollution resistance. The modified membrane prepared by the invention has better hydrophilicity than that of a pure PVC membrane, and the adsorbed protein on the surface of the membrane is obviously reduced. The hydrophilic membrane prepared by the invention can be further developed and utilized as a sewage treatment separation membrane.
Description of the drawings:
FIG. 1 is an atomic force microscope image M0 of the surface morphology of a pure PVC film prepared in an example of the present invention.
Fig. 2 is an atomic force microscope picture M1 of the surface morphology of the PVC-g-PVCL film prepared in example 1 with a starting water contact angle of 78 °.
Fig. 3 is an atomic force microscope picture M2 of the surface morphology of the PVC-g-PVCL film prepared in example 2 with a starting water contact angle of 70 °.
Fig. 4 is an atomic force microscope picture M3 of the surface morphology of the PVC-g-PVCL film prepared in example 3 with an initial water contact angle of 66 °.
Fig. 5 is an atomic force microscope picture M4 of the surface morphology of the PVC-g-PVCL film prepared in example 4 with a starting water contact angle of 60 °.
Fig. 6 is a surface morphology atomic force microscope picture M5 of a PVC-g-PVCL film surface morphology atomic force microscope picture with an initial water contact angle of 56 ° made in example 5.
FIG. 7 dynamic water contact angle plots for the prepared pure PVC film (M0), the synthesized PVC-g-PVCL films (M1, M2, M3, M4 and M5) at different VCL charge concentrations in the examples of the present invention.
FIG. 8 is a graph showing the adsorption amounts of BSA protein to pure PVC membranes (M0) and PVC-g-PVCL membranes (M1, M2, M3, M4 and M5) synthesized at different VCL feed concentrations in the examples of the present invention.
Detailed Description
The following examples are presented to enable one of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.
Example 1:
(1) synthesis of PVC-g-PVCL copolymer: weighing 3g of PVC, dissolving in 50 mL of NMP, completely dissolving at 70 ℃, cooling to room temperature, and filling with N2After 10 minutes, 0.1 g of CuCl, 230. mu.L of PMDETA, and 0.01mol of vinylcaprolactam were added. The gas present was evacuated with a vacuum pump, the reaction was then placed in a 70 ℃ oil bath for 8 h, finally precipitated with a large amount of water and absolute ethanol, the product was washed and dried in an oven at 50 ℃.
(2) Preparation of PVC-g-PVCL copolymer flat membrane: weighing 2g of the PVC-g-PVCL copolymer synthesized in the step (1) and 0.67g of polyethylene glycol (molecular weight is 20000), dissolving in 14g of NMP at 60 ℃ under stirring, completely dissolving, and standing for defoaming for 24 h. The casting solution was dropped on a dried glass plate, and a flat membrane was scraped with a scraper having a size of 200 μm. The nascent film was rapidly immersed in pure water at 25 ℃ and when the film was sufficiently detached from the glass plate, the film sample was taken out. Washing for 2-3 times, and finally storing the membrane sample in pure water for later use.
The initial water contact angle of a pure PVC membrane (marked as M0) is 86 degrees, and the adsorption quantity of bovine serum albumin BSA is 277.6 mu g/cm2(ii) a The initial water contact angle of the PVC-g-PVCL membrane (marked as M1) prepared in the example is 78 degrees, and the adsorption quantity to bovine serum albumin BSA is 176.9 mug/cm2(ii) a The result shows that the hydrophilic performance and the pollution resistance of the PVC membrane are obviously improved after the grafting of the PVCL.
Example 2:
(1) synthesis of PVC-g-PVCL copolymer: the main procedure is the same as in example 1, with the main difference that VCL is added in an amount of 0.02mol, and the remainder of the material is the same as in example 1.
(2) Preparation of PVC-g-PVCL copolymer flat membrane: the same as in example 1.
In this example, the initial water contact angle of the obtained PVC-g-PVCL membrane (marked as M2) is 70 degrees, and the adsorption quantity to BSA is 121.6 mug/cm2。
Example 3:
(1) synthesis of PVC-g-PVCL copolymer: the main procedure is the same as in example 1, with the main difference that VCL is added in an amount of 0.03mol, and the remainder of the material is the same as in example 1.
(2) Preparation of PVC-g-PVCL copolymer flat membrane: the same as in example 1.
In this example, the initial water contact angle of the obtained PVC-g-PVCL membrane (marked as M3) is 66 degrees, and the adsorption quantity to BSA is 90.3 mug/cm2。
Example 4:
(1) synthesis of PVC-g-PVCL copolymer: the main procedure is the same as in example 1, with the main difference that VCL is added in an amount of 0.04mol, and the remainder of the material is the same as in example 1.
(2) Preparation of PVC-g-PVCL copolymer flat membrane: the same as in example 1.
In this example, the initial water contact angle of the obtained PVC-g-PVCL membrane (marked as M4) is 60 degrees, and the adsorption quantity to BSA is 58.8 mug/cm2。
Example 5:
(1) synthesis of PVC-g-PVCL copolymer: the main procedure is the same as in example 1, with the main difference that VCL is added in an amount of 0.05mol, and the remainder of the material is the same as in example 1.
(2) Preparation of PVC-g-PVCL copolymer flat membrane: the same as in example 1.
In this example, the initial water contact angle of the obtained PVC-g-PVCL membrane (marked as M5) is 56 degrees, and the adsorption quantity to BSA is 24.0 μ g/cm2。
Comparative example: preparation of pure PVC film (M0): 2g of PVC polymer and 0.67g of polyethylene glycol (molecular weight 20000) are weighed, dissolved in 14g of NMP at 60 ℃ under stirring, and after complete dissolution, the mixture is kept stand for defoaming for 24 hours. The casting solution was dropped on a dried glass plate, and a flat membrane was scraped with a scraper having a size of 200 μm. The nascent film was rapidly immersed in pure water at 25 ℃ and when the film was sufficiently detached from the glass plate, the film sample was taken out. Washing for 2-3 times, and finally storing the membrane sample in pure water for later use.
Claims (5)
1. A preparation method of an anti-pollution polyvinyl chloride film comprises the following steps: (1) taking polyvinyl chloride (PVC) as a membrane material and Vinyl Caprolactam (VCL) as a monomer, and synthesizing an amphiphilic copolymer PVC-g-PVCL by Atom Transfer Radical Polymerization (ATRP); (2) preparing a separation membrane by using the synthesized PVC-g-PVCL as a membrane forming material through an immersion phase inversion method;
the PVC-g-PVCL copolymer in the step (1) is synthesized by the following method: weighing dry PVC powder, putting the powder into N-methyl pyrrolidone (NMP), stirring at 70 ℃ to completely dissolve the PVC powder, and cooling the solution to room temperature; charging nitrogen for 10min, and adding catalyst cuprous chloride (CuCl), ligand pentamethyl dipropylene triamine (PMDETA) and monomer VCL; pumping out gas in the reaction liquid by using a vacuum pump, sealing the reactor, carrying out reaction at 70 ℃, precipitating by using absolute ethyl alcohol and pure water, washing and drying to obtain a product;
wherein the step (2) for preparing the PVC-g-PVCL separation membrane comprises the following specific steps: weighing PVC-g-PVCL copolymer and polyethylene glycol (PEG), placing the PVC-g-PVCL copolymer and the PEG in an NMP solvent, stirring at 60 ℃ to completely dissolve, standing and defoaming the membrane casting solution for 24 hours, and scraping a separation membrane by using a scraper; rapidly immersing the primary membrane in a coagulant, taking out a membrane sample after the membrane is completely solidified, and storing the membrane sample in pure water for later use;
in the reaction process, the concentration of the PVC powder is 30-90 g/L; the feeding concentration of the monomer VCL is 0.1-1 mol/L; the cuprous chloride concentration is 0.01-0.03 mol/L; the concentration of the PMDETA is 0.01-0.03 mol/L; the reaction time is 6-24 h;
the mass percentage of the PVC-g-PVCL copolymer is 10-15 percent of the total weight of the membrane casting solution; the mass percent of the added PEG accounts for 2-6% of the total weight of the casting solution; the average molecular weight of PEG is 8000-20000 g/mol.
2. The method for preparing an anti-pollution polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: the size of a film scraping knife used for film preparation is 100-300 mu m.
3. The method for preparing an anti-pollution polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: the coagulant used for preparing the film is pure water, and the temperature is 25 ℃.
4. The method for preparing an anti-pollution polyvinyl chloride film according to claim 1, wherein the method comprises the following steps: the prepared separation membrane is a flat membrane.
5. An anti-contamination polyvinyl chloride film, which is produced by the production method according to any one of claims 1 to 4.
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| CN108579438A (en) * | 2018-05-16 | 2018-09-28 | 天津工业大学 | A kind of large-flux anti-pollution Pvc Ultrafiltration Membrane and preparation method thereof |
| CN110898686A (en) * | 2018-09-17 | 2020-03-24 | 天津工业大学 | Preparation method of hydrophilic temperature-sensitive polyvinyl chloride separation membrane and product |
| CN114669203A (en) * | 2020-12-01 | 2022-06-28 | 赖枝帅 | Anti-pollution modified polyvinyl chloride composite membrane |
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| CN102558595A (en) * | 2011-12-15 | 2012-07-11 | 宁波大学 | Surface modification method for polyvinylidene fluoride (PVDF) film or polyvinyl chloride (PVC) film |
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