Method for in-situ polymerization and modification of polyvinylidene fluoride microporous membrane

A technology of polyvinylidene fluoride and in-situ polymerization, applied in the field of membrane separation, can solve the problems of low water flux, low surface energy, membrane fouling, etc., and achieve the effect of simple preparation method, mild reaction conditions and good repeatability

Active Publication Date: 2012-07-11
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the characteristics of low surface energy make PVDF microporous membranes have strong hydrophobicity
When dealing with aqueous phase separation systems, there are often two problems: one is low water flux; the other is that organic matter and protein are easily adsorbed, causing membrane fouling, resulting in decreased membrane flux and shortened membrane life.
The highly hydrophilic polymer is not suitable as a hydrophilic modifier because of its poor compatibility with the matrix resin, resulting in phase separation.

Method used

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  • Method for in-situ polymerization and modification of polyvinylidene fluoride microporous membrane
  • Method for in-situ polymerization and modification of polyvinylidene fluoride microporous membrane
  • Method for in-situ polymerization and modification of polyvinylidene fluoride microporous membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Step (1). Dissolve 100 grams of polyvinylidene fluoride in 900 grams of triethyl phosphate, stir for 72 hours at 75 ° C, and the stirring speed is 100 rpm to make a film-forming precursor solution;

[0023] Step (2). Keep the stirring temperature and stirring speed constant, add 20 grams of active solution to the film-forming precursor solution under nitrogen protection to carry out in-situ polymerization reaction, after reacting for 48 hours, stop the nitrogen protection, and expose the reactant to the Terminate the reaction in the air, keep the reaction temperature constant for 36 hours, and obtain the casting solution after defoaming;

[0024] The components of the active solution are azobisisobutyronitrile, hydroxyethyl methacrylate and triethyl phosphate in a mass ratio of 1:150:130;

[0025] Step (3). The casting solution is processed by a film forming machine to form a primary film;

[0026] Step (4). The nascent film was directly immersed in a deionized water b...

Embodiment 2

[0030] Step (1). Dissolve 200 grams of polyvinylidene fluoride in 800 grams of triethyl phosphate, stir for 5 hours at 125 ° C, and the stirring speed is 1000 rpm to make a film-forming precursor solution;

[0031] Step (2). Keep the stirring temperature and stirring speed constant, add 300 grams of active solution into the film-forming precursor solution under the protection of nitrogen to carry out in-situ polymerization reaction, after reacting for 2 hours, stop the protection of nitrogen, and expose the reactant to the Terminate the reaction in the air, keep the reaction temperature constant for 18 hours, and obtain the casting solution after defoaming;

[0032] The components of the active solution are azobisisobutyronitrile, methyl methacrylate and triethyl phosphate in a mass ratio of 1:150:130;

[0033] Step (3). The casting solution is processed by a film forming machine to form a primary film;

[0034] Step (4). After the primary film is formed, immerse it in a coag...

Embodiment 3

[0037] Step (1). Dissolve 300 grams of polyvinylidene fluoride in 700 grams of triethyl phosphate, stir at 100 ° C for 24 hours, and the stirring speed is 600 rpm to make a film-forming precursor solution;

[0038] Step (2). Keep the stirring temperature and stirring speed constant, add 80 grams of active solution into the film-forming precursor solution under the protection of nitrogen to carry out in-situ polymerization reaction, after reacting for 36 hours, stop the protection of nitrogen, and expose the reactant to the Terminate the reaction in the air, keep the reaction temperature constant for 24 hours, and obtain the casting solution after defoaming;

[0039] The components of the active solution are azobisisobutyronitrile, hydroxypropyl methacrylate and triethyl phosphate in a mass ratio of 1:150:130;

[0040] Step (3). The casting solution is processed by a film forming machine to form a primary film;

[0041]Step (4). Immerse the primary film in a deionized water ba...

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Abstract

The invention relates to a method for in-situ polymerization and modification of a polyvinylidene fluoride microporous membrane. In the method, polyvinylidene fluoride microporous is dissolved in triethyl phosphate at first to prepare membrane-forming precursor solution, active solution is added into the membrane-forming precursor solution for in-situ polymerization under nitrogen protection, the mixture is kept static for 18-36 hours at the reaction temperature after reaction, membrane casting solution is prepared via deaeration and is processed by a membrane forming machine to prepare a primary membrane, the primary membrane is soaked in a coagulating bath for 0-3 hour(s) and is then transferred into an deionized water bath to be immersed for 1-48 hour(s) so as to be cured into a membrane, the membrane is naturally dried in the air at the room temperature, and thus the dry hydrophilic polyvinylidene fluoride membrane is prepared. The method is environmentally friendly, the reaction conditions are mild, the preparation method is simple, modification and preparation are completed simultaneously, the repeatability is good, the method cannot be limited by the type of the microporous membrane, a high-flux separating membrane can be obtained with no needs for external pore-forming agents, and the prepared microporous membrane is a dry hydrophilic membrane.

Description

technical field [0001] The invention belongs to the technical field of membrane separation, and relates to a method for in-situ polymerizing and modifying polyvinylidene fluoride microporous membranes. Background technique [0002] As a membrane material with excellent comprehensive performance, polyvinylidene fluoride (PVDF) has attracted more and more attention due to its outstanding chemical stability, thermal stability, mechanical properties and dielectric properties, and has a wide range of applications in the field of separation membranes. application prospects. However, the characteristic of low surface energy makes PVDF microporous membrane have strong hydrophobicity. Two problems often arise when dealing with aqueous phase separation systems: one is low water flux; the other is that organic matter and proteins are easily adsorbed, causing membrane fouling, resulting in a decrease in membrane flux and shortened membrane life. Therefore, it is very necessary to incr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/34
Inventor 刘富薛立新陶咪咪
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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