Porous membrane and pore-forming method thereof

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...

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