Composite thermotropic phase separation film-making method

A technology of thermally induced phase separation and membrane-making liquid, which is applied in the field of membrane manufacturing, can solve problems such as low flux, inability to form strength, and insufficient expansion, and achieve the effect of excellent performance and increased strength

Active Publication Date: 2009-04-01
湖南坎普尔环保技术有限公司
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  • Summary
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] When using the M-TIPS method to prepare polymer porous membranes, although the selection range of diluents and polymers has been greatly improved compared with the classic thermally induced phase separation method However, the expansion is not thorough enough, and commonly used membrane materials such as polysulfone, polyethersulfone, and polyacrylonitrile are still excluded; at the same time, many membrane systems cannot form a strong, strong membrane when thermally induced phase separation occurs. Instead of an interpenetrating network structure with high flux, it forms a spherulite stacking structure with poor strength and low flux, and the size of the spherulites is difficult to control during the membrane forming process; in addition, it is impossible to form a finer ultrafiltration with a dense separation layer membrane

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Embodiment 1: PVDF powder (kynar761, Mw=375,000), PEG400, DMAc, triethyl phosphate (percentage by weight are respectively 40%, 10%, 30% and 20%) are added together into a specially designed dissolving tank In the middle, pass nitrogen to protect, heat to 150°C, stir to dissolve it into a homogeneous solution, then stir for more than 3 hours, then stop stirring, keep it at 150°C for defoaming for more than 6 hours. After defoaming, the intubated spinning plate is preheated and kept at 150°C, and the hollow molding liquid (inner core liquid)-polyethylene glycol 200 and DMAc 1:1 mixture is transferred from the metering pump or the high-level liquid tank. Continuously and quantitatively flow out from the central cannula of the spinneret, and then increase the nitrogen pressure to make the film-making liquid squeeze out from the spinneret. After walking for a short distance (≤10cm) in the air, immediately drop the formed film-making liquid vertically into the quenching liqui...

example 2

[0040] Example 2: The composition of the film-making solution is adjusted to PVDF powder (Sanaifu 904, Mw=600,000-800,000), PEG400, DMAc, and triethyl phosphate by weight percentages of 22.5%, 12.5%, 35% and 30% respectively , Spinning temperature is outside 135 ℃, all the other conditions are with example 1.

[0041] It is measured that the inner diameter of the PVDF hollow fiber membrane is 0.8mm, the outer diameter is 1.35mm, the bubble point pressure is 0.18MPa, the tensile breaking strength is 6.8MPa, and the tensile elongation is 320%. The flux of water is 438L / m 2 h.

example 3

[0042] Example 3: Except that the quenching liquid is 10% water+45% PEG200 and 45% DMAc, all the others are the same as Example 1.

[0043] It is measured that the inner diameter of the PVDF hollow fiber membrane is 0.9mm, the outer diameter is 1.36mm, the bubble point pressure is 0.28MPa, the tensile breaking strength is 10.8MPa, and the tensile elongation is 280%. The flux of water is 43L / m 2 h.

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PUM

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Abstract

The invention relates to a composite thermotropic phase isolated membrane preparation method which is characterized in that used composite diluent is the mixture of water-soluble good solvent and water-soluble additive of polymers. The membrane forming separation is a composite process which mainly takes the thermotropic membrane phase separation as the dominant role and non-solvent induced phaseseparation as the subsidiary role. The membrane prepared through the method has the advantages of high abruption strength, high abruption elongation and high water flux. The method is applicable to the preparation of membranes which are made of a plurality of polymers, including polyvinylidene fluoride, polysulfone, polyether sulfone, polyvinyl chloride and polyacrylonitrile. The performances of the membranes are improved greatly. Thus, the membranes can be widely applied to the fields of drinking water advanced treatment, pretreatment before reverse permeation, membrane bioreactor wastewatertreatment, reclaimed water reuse, etc.

Description

Technical field [0001] The invention belongs to the field of membrane manufacturing, and relates to a method for preparing a polymer hollow fiber or capillary porous membrane by using an improved thermally induced phase separation method (TIPS method), and particularly discloses a method for preparing a polymer hollow fiber or capillary porous membrane by using a composite thermally induced phase separation method (CTIPS method) Polymer hollow fiber or capillary porous membrane (including microfiltration membrane and ultrafiltration membrane) process. The prepared porous membrane can be used in fields such as environmental protection and water treatment. Background technique [0002] Polymer porous membranes (including microfiltration membranes and ultrafiltration membranes) have a variety of preparation methods, the most common of which are the non-solvent-induced phase separation method (NIPS method), also known as the "immersion precipitation method" (IP method) and melt-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D67/00B01D69/08
Inventor 祝振鑫黄立州孟广祯
Owner 湖南坎普尔环保技术有限公司
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