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Method for preparing polyvinylidene fluoride flat plate porous film by thermal phase separation process

A polyvinylidene fluoride, thermally induced phase separation technology, applied in semi-permeable membrane separation, chemical instruments and methods, membrane technology and other directions, can solve the problems of high low temperature brittleness, poor oxidation resistance and ultraviolet resistance, poor weather resistance, etc. Achieve the effect of narrow pore size distribution, diverse structure and simple preparation process

Inactive Publication Date: 2006-03-22
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the film materials used in TIPS film production are concentrated on polypropylene and polyethylene, but polypropylene has high low temperature brittleness and poor weather resistance; polyethylene has poor oxidation resistance and ultraviolet resistance, so the films made of these two materials are used in practical applications. subject to certain restrictions

Method used

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  • Method for preparing polyvinylidene fluoride flat plate porous film by thermal phase separation process
  • Method for preparing polyvinylidene fluoride flat plate porous film by thermal phase separation process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] (1) PVDF (M w 180000) and γ-butyrolactone into the high-temperature reactor, wherein the mass percentage of PVDF is 25%, the mass percentage of diluent is 75%, the mixed system is heated to 110 ° C, fully stirred, until the solution is Homogeneous solution, stop heating, defoam for 30s, let it stand, and make casting solution;

[0024] (2) Preheat the mold in an atmospheric oven at 110°C for 1 hour;

[0025] (3) Pour the casting liquid into the mold for calendering and then put it into an oven, and keep it at a temperature of 110°C for 20 minutes;

[0026] (4) Take out the mold and immediately place it in ice water for 2 hours to cool the casting solution and make the polymer crystallize and solidify to form a film;

[0027] (5) The formed membrane is taken out from the mold, and soaked in the extractant for 2 days to extract the diluent in the membrane.

[0028] The prepared membrane has a thickness of 300μm and a water flux of 11kg / m 2 .h, the average pore diamete...

Embodiment 2

[0030] (1) PVDF (M w 180,000) and γ-butyrolactone into a high-temperature reactor, wherein the mass percentage of PVDF is 35%, and the mass percentage of diluent is 65%. The mixed system is heated to 120°C and fully stirred until the solution is Homogeneous solution, stop heating, defoam for 60s, let stand, and make casting solution;

[0031] (2) Preheat the mold in a normal pressure oven at 120°C for 1.2h;

[0032] (3) Pour the casting solution into the mold for calendering and then put it into an oven, and keep it at a temperature of 120°C for 20 minutes;

[0033] (4) Take out the mold and immediately place it in ice water for 2 hours to cool the casting solution and make the polymer crystallize and solidify to form a film;

[0034] (5) The formed membrane is taken out from the mold and put into the extractant soaking for 3 days to extract the diluent in the membrane.

[0035] The prepared membrane has a thickness of 310μm and a water flux of 7kg / m 2 .h, the average pore...

Embodiment 3

[0037] (1) PVDF (M w 180,000) and γ-butyrolactone into a high-temperature reactor, wherein the mass percentage of PVDF is 35%, and the mass percentage of diluent is 65%. The mixed system is heated to 120°C and fully stirred until the solution is Homogeneous solution, stop heating, defoam for 60s, let stand, and make casting solution;

[0038] (2) Preheat the mold in a normal pressure oven at 120°C for 1.2h;

[0039] (3) Pour the casting solution into the mold for calendering and then put it into an oven, and keep it at a temperature of 120°C for 20 minutes;

[0040] (4) Take out the mold and immediately place it at room temperature for 8 hours to cool the casting solution and make the polymer crystallize and solidify to form a film;

[0041] (5) The formed membrane is taken out from the mold and put into the extractant soaking for 3 days to extract the diluent in the membrane.

[0042] The prepared membrane has a thickness of 400 μm, an average pore diameter of 0.0627 μm, a...

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Abstract

The thermal phase separation process for preparing plate porous polyvinylidene fluoride film includes the following steps: mixing and heating polyvinylidene fluoride in 25-35 wt% and diluent in 65-75 wt% through stirring in high temperature reactor to obtain homogeneous polymer solution, debubbling and letting stand to obtain film casting liquid; preheating mold; pouring the film casting liquid into the mold and rolling to form; setting in cooling environment to cool and to crystallize polymer into film; setting the film inside extractant to eliminate diluent and obtain the plate porous polyvinylidene fluoride film. Prepared plate porous polyvinylidene fluoride film via the said process has narrow pore size distribution, various structure and powerful adaptability, and the preparation process is simple.

Description

technical field [0001] The invention relates to a method for preparing a polyvinylidene fluoride (PVDF) flat microporous membrane by a heat-induced phase separation process. It belongs to the preparation technology of polyvinylidene fluoride flat microporous membrane. Background technique [0002] Membrane separation technology has attracted increasing attention due to its high efficiency, energy saving, and pollution-free characteristics, and has become an effective technology to replace traditional separation methods. Microporous membrane is currently the most widely used separation membrane with the largest total sales, and is widely used in food, medicine, drinking water, urban sewage treatment, etc. At present, most microporous membranes are prepared by non-solvent-induced phase inversion method. The microporous membrane obtained by this method has a wide pore size distribution and poor strength. Thermally induced phase separation (TIPS) is a new method for preparing...

Claims

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Application Information

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IPC IPC(8): B01D71/34B01D69/06
Inventor 陈翠仙苏仪
Owner TSINGHUA UNIV
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