A dry-wet phase conversion method for preparing microfiltration membrane

A technology of microfiltration membrane and phase inversion, applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve problems such as unsuitable for microfiltration application, difficult continuous production, low efficiency, etc.

Active Publication Date: 2022-01-04
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the long film forming time in the dry production process, continuous production is usually difficult and the efficiency is low
However, wet and dry-wet methods often form asymmetric membranes with skin layers, which are not suitable for microfiltration applications.

Method used

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  • A dry-wet phase conversion method for preparing microfiltration membrane
  • A dry-wet phase conversion method for preparing microfiltration membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029]It is 12% by macromolecular PVDF mass percentage composition, the mass percentage composition of the second kind of macromolecular polyvinylpyrrolidone (PVP) is 11.5%, the solvent DMAc mass percentage composition is 68%, the quality of small molecule porogen magnesium chloride The percentage content 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 dissolve to form a completely uniform PVDF casting solution, and left to defoam. Afterwards, scrape the above-mentioned casting solution at 30°C, pour it on a glass plate, then use a scraper to make a 200 μm nascent film, and then keep the nascent film plate at 130°C for 60 seconds in an air atmosphere. , so that the nascent membrane phase separation occurs, and then put it into a water bath at 30 ° C to completely solidify the nascent membrane and fall off naturally, then put the PVDF membra...

Embodiment 2

[0031] It is 12% by macromolecular PVDF mass percentage composition, the mass percentage composition of the second kind of macromolecular polyvinylpyrrolidone (PVP) is 11.5%, the solvent DMAc mass percentage composition is 68%, the quality of small molecule porogen magnesium chloride The percentage content 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 dissolve to form a completely uniform PVDF casting solution, and left 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 220 μm nascent film, and then the nascent film was kept at 150°C for 45 seconds in an air atmosphere. , so that the nascent membrane phase separation occurs, and then put it into a water bath at 30 ° C to completely solidify the nascent membrane and fall off naturally, then put...

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, the above-mentioned casting solution was scraped at 35° C., poured on a glass plate, and then scraped with a scraper to form a nascent eco-film, and then the nascent eco-film was kept at 100° C. for 30 seconds in an air atmosphere, so that The nascent eco-membrane undergoes phase separation, and then put it into a water bath at 35°C to completely solidify the nascent eco-membrane to form a film and fal...

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Abstract

The invention discloses a method for preparing a microfiltration membrane by dry-wet phase transformation, which mainly prepares a polymer film casting liquid system with a low critical solution temperature, and adopts a dry-wet phase transformation method to prepare the membrane. The polymer film casting solution of the present invention is homogeneously stable at low temperatures, but phase separation occurs at high temperatures, and the corresponding film-making mechanism is different from the traditional dry-wet phase inversion method. The dry process of the present invention is rapidly produced due to temperature differences The thermally induced phase separation forms the skeleton and pore structure of the membrane, and finally obtains the required sponge-like pore structure and skin-free microfiltration membrane. The formed microfiltration membrane has uniform pore size, high porosity, and good connectivity. Quantity, high strength and other characteristics. In addition, the dry-wet phase inversion method of the present invention overcomes the disadvantages of the traditional dry film-making process, such as long time, difficulty in continuous production, large solvent evaporation, and high recovery requirements, while avoiding the traditional wet method or dry-wet phase inversion method Finger holes or large cavity structures are often formed.

Description

technical field [0001] The invention belongs to the technical field of polymer membrane separation, and in particular relates to a method for preparing a microfiltration membrane by dry-wet phase conversion. Background technique [0002] Microfiltration membrane technology is widely used in material filtration and separation, concentration pretreatment, medical purification and battery diaphragm and other fields. Microfiltration membranes made of polyvinylidene fluoride (PVDF) have excellent performance in solvent resistance, acid and alkali resistance, ultraviolet resistance and weather resistance, and have broad market prospects. The commonly used polymer film preparation method is mainly the phase inversion method, which can be divided into dry method, wet method and dry-wet method according to whether the solvent evaporates during the film production process. The dry method is a film-forming process in which the solvent in the scraped nascent film is completely evaporat...

Claims

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Application Information

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