Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Preparation method for beta crystal phase polyvinylidene fluoride hollow fiber porous membrane

A technology of polyvinylidene fluoride and polyvinylidene fluoride resin, which is applied in the field of preparation of β-crystalline polyvinylidene fluoride hollow fiber porous membranes, can solve problems such as restricting the development of PVDF microporous membrane technology and affecting the strength of PVDF membranes, and achieves effective It is conducive to full transformation, reduced post-processing procedures, and sufficient and uniform stretching effects

Active Publication Date: 2011-09-14
TSINGHUA UNIV
View PDF1 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the porous membrane prepared by the TIPS method, PVDF mainly exists in the α crystal form, and there are a large number of spherulites in the microporous membrane, which affects the strength of the PVDF membrane to a large extent, and restricts the preparation of PVDF micropores by the TIPS method. Further development of membrane technology

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0027] The preparation method of polyvinylidene fluoride porous membrane of the present invention is carried out according to the following steps:

[0028] 1) mixing polyvinylidene fluoride resin with diluent; wherein the mass percentage of polyvinylidene fluoride resin in the mixture is 15-75%;

[0029] 2) Put the mixture in step 1) into a high-temperature stirred tank, heat up to 140°C-220°C to form a polymer homogeneous solution, and let it stand for defoaming;

[0030] 3) Extrude the polymer homogeneous solution obtained in step 2) and the liquid forming the inner cavity of the fiber through a double-tube die, and directly immerse in the cooling liquid to cool and solidify to form a hollow fiber membrane;

[0031] 4) carrying out liquid bath stretching to the hollow fiber membrane obtained in step 3);

[0032] 5) annealing the hollow fiber membrane obtained in step 4);

[0033] 6) rewinding the hollow fiber membrane obtained in step 5);

[0034] 7) Extracting the diluen...

Embodiment 1

[0043]The weight average molecular weight is 300,000 polyvinylidene fluoride resin and benzophenone, and its composition is that the weight percentage of polyvinylidene fluoride resin is 35%, and the weight percentage of benzophenone is 65%, put into Heat up to 200°C in a high-temperature stirred tank, stir and mix evenly to form a homogeneous polymer solution, and let stand for 24 hours. Then, the polymer homogeneous solution and the core liquid glycerin were extruded through a double-tube die and directly immersed in a cooling liquid bath at 80° C. to separate and solidify the solution into a film. The cooling liquid bath was a water bath. The cured hollow fiber membrane is subjected to three-stage hot water stretching. The temperature of the first-stage hot water drafting device is 70°C, and the temperature of the third-stage hot water drafting device is 90°C. The temperature gradient is 10°C, and the total drafting ratio of the hollow fiber membrane in the hot water drafti...

Embodiment 2

[0046] The weight average molecular weight is 200,000 polyvinylidene fluoride resin and benzophenone, and its composition is that the weight percentage of polyvinylidene fluoride resin is 35%, and the weight percentage of benzophenone is 65%, put into Heat up to 180°C in a high-temperature stirred tank, stir and mix evenly to form a homogeneous polymer solution, and let stand for 24 hours. Then, the polymer homogeneous solution and the core liquid glycerin were extruded through a double-tube die and directly immersed in a cooling liquid bath at 80° C. to separate and solidify the solution into a film. The cooling liquid bath was a water bath. The cured hollow fiber membrane is subjected to three-stage hot water stretching. The temperature of the first-stage hot water drafting device is 70°C, and the temperature of the third-stage hot water drafting device is 90°C. The temperature gradient is 10°C, and the total drafting ratio of the hollow fiber membrane in the hot water draft...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
thicknessaaaaaaaaaa
pore sizeaaaaaaaaaa
tensile strengthaaaaaaaaaa
Login to View More

Abstract

The invention provides a preparation method of a beta crystalline phase polyvinylidene fluoride hollow fibrous membrane, relating to a membrane manufacture technology of preparing the polyvinylidene fluoride hollow fibrous membrane by a thermally induced phase separation method, in particular to the method of preparing the polyvinylidene fluoride hollow fibrous membrane with the beta crystalline phase of high-flux and high strength by the thermally induced phase separation method. The invention is characterized in that on the basis of a porous membrane prepared by the thermally induced phase separation method, a continuous post-processing method combining stretching and annealing is additionally carried out so as to obtain as much as possible beta crystal form polyvinylidene fluoride intensity; the polyvinylidene fluoride hollow fiber membrane prepared by the method has even distribution of a pore diameter and high water flux; and the product of which the intensity is not processed isimproved more greatly.

Description

technical field [0001] The invention relates to a preparation process of a polyvinylidene fluoride hollow fiber membrane, in particular to a method for preparing a high-flux and high-strength polyvinylidene fluoride hollow fiber membrane of a β crystal phase by a heat-induced phase separation method. Background technique [0002] Polyvinylidene fluoride has excellent thermal stability, corrosion resistance, non-combustibility, anti-ultraviolet aging and other properties, and has high strength and wear resistance, so it has attracted extensive attention in the field of separation membranes in recent years. In terms of microfiltration and ultrafiltration, polyvinylidene fluoride has been used as a membrane with excellent performance, and its preparation process is mostly non-solvent precipitation gel phase inversion method (NIPS). This method has been widely used since the 1980s, including the preparation of flat homogeneous membranes, composite membranes and hollow fiber memb...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/34B01D69/08
CPCB01D71/34B01D69/087B01D69/08
Inventor 王晓琳田野林亚凯杨健衷咏
Owner TSINGHUA UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com