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Porous film made of polyunsymfluoroethylene, and its preparation method

A polyvinylidene fluoride, porous membrane technology, applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve the problems of uneven membrane pore structure, poor strength, and loose polyvinylidene fluoride spherulite accumulation. , to achieve the effects of environmental tolerance and good water permeability, high strength, and excellent light aging resistance

Active Publication Date: 2008-05-28
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The use of this solvent does not require adding any inorganic particles or nucleating agents, and can solve the problems of loose polyvinylidene fluoride spherulites, uneven membrane pore structure, and poor strength.

Method used

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  • Porous film made of polyunsymfluoroethylene, and its preparation method
  • Porous film made of polyunsymfluoroethylene, and its preparation method
  • Porous film made of polyunsymfluoroethylene, and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Polyvinylidene fluoride-benzophenone system. The polyvinylidene fluoride benzophenone mixture with a mass concentration of 5% was sealed in a test tube filled with nitrogen, placed in an oven at 210°C, and fully dissolved for 24 hours. Thickness 0.13μm) scraping film, film thickness 150μm. The glass flakes were then quenched to 30°C. After cooling, place the glass slide carrying the film in 95% ethanol to extract the benzophenone. Ethanol was changed every 24 hours for a total of two changes. At this time, the polyvinylidene fluoride film can be peeled off from the glass sheet in a wet state, placed in the air, and dried. Electron microscope observation of the fracture (liquid nitrogen freezing brittle fracture) and surface structure, the electron microscope photos show that the membrane pore diameter is about 0.5 μm.

Embodiment 2

[0032] Polyvinylidene fluoride-benzophenone system. Seal the polyvinylidene fluoride benzophenone mixture with a mass concentration of 10% in a test tube filled with nitrogen, place it in an oven at 180°C, and fully dissolve it for 24 hours. Take out the glass sheet (thickness 0.13 μm ) on the scraping film. The film thickness was 150 μm. Quench to 80°C, put it in an environment of 0°C to cool completely. The benzophenone was extracted by placing the glass slide carrying the film in 95% ethanol. Ethanol was changed every 24 hours for a total of two changes. At this time, the polyvinylidene fluoride film can be peeled off from the glass sheet in a wet state, placed in the air, and dried. The fracture surface (liquid nitrogen freeze brittle fracture) and surface structure were observed by electron microscope. Electron micrographs show that the membrane pore diameter is about 0.5 μm.

Embodiment 3

[0034]Polyvinylidene fluoride-benzophenone system. The polyvinylidene fluoride benzophenone mixture with a mass concentration of 40% was sealed in a test tube filled with nitrogen, placed in an oven at 200°C, fully dissolved for 24 hours, and the high-temperature solution was squeezed out. 0.13μm) on the film. The film thickness is 200 μm. The glass flakes were then quenched to 0°C. After complete cooling, place the glass slide carrying the film in 95% ethanol to extract the benzophenone. Ethanol was changed every 24 hours for a total of two changes. At this time, the polyvinylidene fluoride film can be peeled off from the glass sheet in a wet state, placed in the air, and dried. The fracture surface (liquid nitrogen freeze brittle fracture) and surface structure were observed by electron microscope. Electron micrographs show that the membrane pore diameter is about 0.3 μm.

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Abstract

A process polyvinylidene fluoride membrane is prepared from polyvinylidene fluoride and diphenyl methanone as solvent through lowering temp of system to trigger phase separation. Said porous membrane has no obvious surface structure, spongy cross-section structure and 0.01-1 micron for pore diameter.

Description

technical field [0001] The invention relates to a method for preparing a porous membrane from polyvinylidene fluoride. In particular, it relates to a method for preparing an isotropic uniform polyvinylidene fluoride porous membrane by using benzophenone as a solvent. The membrane can be used as a microfiltration membrane or an ultrafiltration membrane in industrial or medical microfiltration and ultrafiltration processes, and can also be used as a diaphragm for batteries. Background technique [0002] Polyvinylidene fluoride is a linear polymer obtained by homopolymerization or copolymerization of vinylidene fluoride monomer, and its molecular chain is regular and easy to crystallize. The working temperature range is -40~150℃. Polyvinylidene fluoride has good heat resistance, oxidation resistance, corrosion resistance, wear resistance, impact strength and tensile strength. It has excellent anti-ultraviolet and anti-aging properties, and can maintain stable material perfor...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/34
Inventor 王晓琳杨健赵文明尚伟娟
Owner TSINGHUA UNIV
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