Porous membrane and pore-forming method thereof

A porous membrane and pore-forming technology, applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve problems that have not been reported in the literature

Inactive Publication Date: 2014-04-09
TIANJIN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is no literature report on the preparation of membrane materials by foaming agent.

Method used

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  • Porous membrane and pore-forming method thereof

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preparation example Construction

[0008] In the preparation method of the porous membrane according to the present invention, the solution method for membrane formation, the membrane-forming system includes 15-30wt% polymer, 15-30wt% water-soluble porogen, 40-70wt% organic solvent, each The sum of the components is 100wt%, and the proportion of the foaming pore-forming agent in the casting liquid is 0.1-5wt%.

[0009] In the formula of the present invention, the film-forming polymer is a film-forming material that can be dissolved in a conventional solvent, including polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polysulfone (PS), polyethersulfone (PES );

[0010] The water-soluble porogen is polyethylene glycol (PEG) of different molecular weights, polyvinylpyrrolidone (PVP) or a mixture thereof with a certain mass ratio;

[0011] Described organic solvent is the organic solvent that does not react with foaming pore-forming agent, comprises N, N dimethylformamide (DMF), N, N dimethylacetamide (DMAc...

Embodiment 1

[0016] Polyvinylidene fluoride (PVDF) is used as a film-forming polymer with a content of 20wt%; the water-soluble porogen is PEG with an average molecular weight of 4000, and the content is 25wt%; the organic solvent is DMAc, and the content is 55wt%; Sodium borohydride is selected as the porosity agent, and the content is 5wt‰ of the mass of the entire casting solution; PVDF, PEG and sodium borohydride weighed in proportion are dispersed and dissolved in DMAc to obtain a uniform casting solution. The dry-wet spinning hollow fiber spinning head enters the coagulation bath after being solidified and stretched to obtain the hollow fiber membrane of the present invention, and the obtained membrane is correspondingly marked as 1#. Test the porosity, pure water flux (working pressure 0.1Mpa) and mechanical strength of the membrane.

Embodiment 2

[0018] Take polyacrylonitrile (PAN) as the film-forming polymer, the content is 20wt%; the water-soluble porogen is selected as PEG with an average molecular weight of 4000, and the content is 25wt%; the organic solvent is DMAc, and the content is 55wt%; foaming Sodium borohydride is selected as the agent, and the content is 5wt‰ of the whole casting solution quality; PVDF, PEG and sodium borohydride weighed in proportion are dispersed and dissolved in DMAc to obtain a uniform casting solution, and the casting solution is subjected to conventional After the dry-wet spinning hollow fiber spinneret enters the coagulation bath, solidifies and draws to obtain the hollow fiber membrane of the present invention, the obtained membrane is correspondingly marked as 2#. Test the porosity and pure water flux of the membrane (working pressure 0.1Mpa).

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Abstract

The invention discloses a porous membrane and a pore-forming method of the porous membrane. According to a preparation method, a foaming pore-forming agent is introduced into a membrane-forming system and can generate uniformly distributed trace air bubbles through reaction so as to form a porous structure; therefore, the porosity of the membrane is improved, and macropore defects of the membrane can be avoided. The pore-forming method is applicable to membrane preparation by a solution method and a melting method. The pore-forming method specifically comprises the steps of (1) membrane preparation by the solution method: uniformly mixing a membrane-forming polymer and the foaming pore-forming agent, dissolving the mixture in a solvent to obtain a membrane casting solution containing the foaming pore-forming agent, wherein the membrane casting liquid enters an acidic coagulating bath after being subjected to scraping or is spun through a hollow fiber spinning head, so that the membrane casting liquid is solidified and formed to obtain the porous membrane when the foaming pore-forming agent reacts to form the air bubbles; (2) membrane preparation by the melting method: uniformly mixing the membrane-forming polymer and the foaming pore-forming agent, and obtaining an initial hollow fiber containing the foaming pore-forming agent through conventional hollow fiber membrane melting spinning, and putting the obtained initial hollow fiber into the acidic coagulating bath, wherein the hollow fiber is solidified and formed to obtain the porous membrane when the foaming pore-forming agent reacts to form the air bubbles.

Description

technical field [0001] The invention relates to the technical field of membranes, in particular to a porous membrane and a foaming method for forming holes. Background technique [0002] Membrane separation technology, as a new type of efficient separation, concentration and purification technology, has developed rapidly since the 1960s, and has now become a technology with the characteristics of wide application fields, low energy consumption, simple and easy operation of equipment, and high efficiency. high technology. Membrane material is the core of membrane separation technology. The separation performance of the membrane mainly depends on the chemical affinity between the membrane material and the separated substance and the microporous structure of the membrane material itself, especially the shape, size, distribution and porosity of the micropores. etc. have a direct impact on the flux and rejection of the separation membrane. Commonly used polymer membrane materia...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D69/08B01D71/34B01D71/42B01D67/00
Inventor 黄庆林范明超吴艳杰陈凯凯
Owner TIANJIN POLYTECHNIC UNIV
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