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A Composite Phase Separation Membrane Production Method Based on Low Critical Solution Temperature System

A technology of composite phase separation and dissolution temperature, which is applied in the field of composite phase separation membrane production based on low critical solution temperature system, can solve problems such as low permeation flux, complex process flow, and large environmental pollution

Active Publication Date: 2021-10-22
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The preparation of PVDF micro / ultrafiltration membranes by a single NIPS method requires a lot of process parameters to be adjusted. The porosity of the membrane is low, the resistance is large, and the permeation flux is low; when the membrane is prepared by a single TIPS method, the dissolution temperature of the polymer is very high, usually higher than The melting point of PVDF is above 180°C. It consumes a lot of energy, and most of the solvents used to dissolve polymers need to be extracted with organic solvents. The process is complicated and the environment is polluted.

Method used

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  • A Composite Phase Separation Membrane Production Method Based on Low Critical Solution Temperature System
  • A Composite Phase Separation Membrane Production Method Based on Low Critical Solution Temperature System

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027]It is 12% by macromolecular PVDF mass percentage composition, the mass percentage composition of second kind of macromolecular polyvinylpyrrolidone (PVP) is 11.5%, and solvent dimethylacetamide (DMAc) mass percentage composition is 68%, small The mass percentage of molecular porogen magnesium chloride is 8.5% to configure PVDF casting solution. First, magnesium chloride is completely dissolved in DMAc, then PVDF and PVP are added, stirred and heated at a constant temperature of 30°C to form a completely uniform PVDF casting solution. Let stand to defoam. Afterwards, the above-mentioned casting solution was scraped at 30°C, poured on a glass plate, and then scraped with a scraper to form a nascent film of 200 μm, and then the nascent film was quickly put into a water bath at 90°C to make The nascent membrane undergoes phase separation, solidifies from the liquid phase to form a film, and falls off naturally, and then the PVDF membrane is placed in water to further dissolv...

Embodiment 2

[0030] It is 16% by macromolecular PVDF mass percentage composition, the mass percentage composition of the second kind of macromolecular polyvinylpyrrolidone (PVP) is 4%, the solvent DMAc mass percentage composition is 72%, the quality of small molecule porogen magnesium chloride The percentage content is 8% to configure PVDF casting solution. First, magnesium chloride is completely dissolved in DMAc, then PVDF and PVP are added, stirred and heated at a constant temperature of 25°C to dissolve to form a completely uniform PVDF casting solution, and left to defoam. Afterwards, the above-mentioned casting solution was scraped at 25°C, poured on a glass plate, and then scraped with a scraper to form a nascent film of 220 μm, and then the nascent film was quickly put into a water bath at 85°C to make The nascent membrane undergoes phase separation, solidifies from the liquid phase to form a film, and falls off naturally, and then the PVDF membrane is placed in water to further dis...

Embodiment 3

[0033] It is 12% by macromolecular PVDF mass percentage composition, the mass percentage composition of the second kind of macromolecular polyvinylpyrrolidone (PVP) is 4%, the solvent DMAc mass percentage composition is 73%, the quality of small molecule porogen magnesium chloride The percentage content is 11% to configure PVDF casting solution. Firstly, magnesium chloride is completely dissolved in DMAc, then PVDF and PVP are added, stirred and heated at a constant temperature of 35°C to dissolve to form a completely uniform PVDF casting solution, and left to defoam. Afterwards, scrape the above-mentioned casting solution at 35°C, pour it on a glass plate, then scrape it with a scraper to form a nascent film, and then quickly put the nascent film into a water bath at 90°C to make the nascent The membrane undergoes phase separation, solidifies from the liquid phase to form a membrane, and falls off naturally, and then the PVDF membrane is placed in water to further completely d...

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Abstract

The invention discloses a composite phase separation film-making method based on a low critical solution temperature system. By preparing a polymer film casting liquid system with a low critical solution temperature, a composite method combining a non-solvent-induced phase separation method and a thermally induced phase separation method is adopted. Membranes prepared by phase separation. The polymer film casting solution of the present invention is homogeneously stable at low temperature, but phase separation occurs at high temperature. The corresponding film-making process is different from the traditional film-making process. By adjusting the temperature of the gel bath, the film structure can be adjusted. Form the required sponge-like pore structure or other types of pore structure, so as to obtain the micro / ultrafiltration membrane whose structure is easy to adjust. Compared with membranes prepared by a single non-solvent induced phase separation method or a thermally induced phase separation method, it has the characteristics of large flux, low resistance and high strength.

Description

technical field [0001] The invention belongs to the technical field of polymer membrane separation, and in particular relates to a composite phase separation membrane-making method based on a low critical solution temperature system. Background technique [0002] Microfiltration and ultrafiltration (referred to as micro / ultrafiltration) membrane separation technology is widely used in the fields of material filtration separation, concentration purification and purification. Commonly used polymer membrane materials mainly include polyvinylidene fluoride (PVDF), polyethersulfone (PES), polyacrylonitrile (PAN) and polypropylene (PP). Among them, the micro / ultrafiltration membrane prepared with PVDF has outstanding advantages in solvent resistance, acid and alkali resistance, ultraviolet resistance and weather resistance, and resistance to repeated cleaning of chemicals, and has attracted widespread attention. The preparation method of PVDF membrane is mainly phase separation m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/34B01D69/12B01D67/00
CPCB01D67/0002B01D69/12B01D71/34
Inventor 肖通虎陈伟
Owner NINGBO UNIV