Hydrophilic modification method for polytetrafluoroethylene membrane

A technology of polytetrafluoroethylene film and polytetrafluoroethylene, which is applied in the chemical field, can solve the problems of complex preparation process of chemical treatment methods, decreased thermal and chemical stability of materials, poor hydrophilic stability, etc., and achieves good pollution resistance and light Catalytic performance, remarkable effect of hydrophilic modification, good stability

Active Publication Date: 2015-10-28
深圳市新纳捷科技有限公司
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

At present, researchers at home and abroad mainly use chemical and physical methods including sodium-naphthalene chemical treatment to modify PTFE microporous membranes. The surface contact angle has been reduced from 120° to a level of about 50°, but these modification methods still have some disadvantages
Among them, the preparation process of the chemical treatment method is complicated, and it is easy to lead to the change of the structure of the material itself, resulting in a decrease in the thermal and chemical stability of the material itself; chemical graft modification can only ensure that the membrane material has good hydrophilicity in a short period of time; Although the single physical method is simple to operate, the hydrophilic stability after modification is poor, and the contact angle tends to rise with time.

Method used

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  • Hydrophilic modification method for polytetrafluoroethylene membrane
  • Hydrophilic modification method for polytetrafluoroethylene membrane
  • Hydrophilic modification method for polytetrafluoroethylene membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Embodiment 1: the pretreatment of polytetrafluoroethylene membrane surface plasma

[0048] Using nitrogen as the gas atmosphere, plasma equipment with a voltage of 30 volts, a current of 2 amperes, a discharge distance of 8 mm, and a discharge power of 10,000 Hz, the PTFE film was subjected to plasma pretreatment for 120 seconds. During the treatment process, when high-energy particles such as ions, electrons, and free radicals in the plasma bombard the surface of the membrane, the energy transmitted by them is greater than the bond energy of the chemical bonds C-C and C-F bonds that make up the material molecules, resulting in these chemical bonds under the action of high-energy particles. Cleavage occurs to generate alkyl radicals on the membrane surface. In the process of exposure to air for 10 minutes, these alkyl radicals will react with oxygen and water in humid air to generate relatively stable peroxyl radicals.

[0049] The concentration of free radicals on the...

Embodiment 2

[0050] Embodiment 2: thermal graft polymerization of polytetrafluoroethylene film surface acrylic acid solution

[0051] Put the pretreated polytetrafluoroethylene membrane into the prepared acrylic acid (AA) solution and soak it for 5 minutes, take it out, spread the acrylic acid solution on the surface of the membrane evenly with a glass rod, and sandwich the membrane sample between two clean glass plates. In the middle, put it into a vacuum drying oven at 75°C for graft polymerization for 4 hours. Take out the polytetrafluoroethylene film grafted with polyacrylic acid (PAA) on the surface, wash and remove the acrylic acid monomer and homopolymer adsorbed on the film surface with a large amount of deionized water, and dry it to obtain PTFE / PAA polytetrafluoroethylene film. Vinyl grafted film.

[0052] The surface weight gain rate of the obtained PTFE / PAA polytetrafluoroethylene grafted membrane is 12%. The contact angle of pure water on the surface of the polytetrafluoroet...

Embodiment 3

[0053] Example 3: Titanium dioxide self-assembly on the surface of polytetrafluoroethylene membrane.

[0054] The PTFE / PAA polytetrafluoroethylene graft film that makes in embodiment 2 is in TiO 2 Static immersion in sol for 20 minutes to make TiO 2 Ti 4+ Coordination with the carboxyl groups on PAA assembles to the surface of the grafted membrane. After washing with deionized water and drying, PTFE / PAA / TiO 2 Hydrophilic modified membrane.

[0055] The resulting PTFE / PAA / TiO 2 The surface weight gain rate of the hydrophilic modified membrane was 21%. The pure water contact angle on the surface of the polytetrafluoroethylene membrane was reduced to 35° on the basis of Example 2. The above-mentioned polytetrafluoroethylene hydrophilic modified membrane was continuously filtered in 1 g / L bovine serum albumin solution for 120 minutes, and the contaminated membrane was subjected to ultraviolet light with an intensity of 500 watts for 15 minutes. The polytetrafluoroethylene pr...

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Abstract

The inveniton provides a hydrophilic modification method for a polytetrafluoroethylene membrane. The method comprises the following steps: step 1, subjecting the polytetrafluoroethylene membrane to plasma treatment under a nitrogen atmosphere, and allowing the surface of the polytetrafluoroethylene membrane to generate relatively-stable free radicals and active sites; step 2, placing the polytetrafluoroethylene membrane into an acylic acid solution and carrying out static impregnation for a period of time, then taking the polytetrafluoroethylene membrane out of the solution and then placing the polytetrafluoroethylene membrane between two glase plates, and carrying out thermochemical polymerization in a vacuum drying oven so as to obtain the polytetrafluoroethylene membrane with the surface grafted with polyacrylic acid; and step 3, subjecting the polytetrafluoroethylene membrane to static impregnation in a titanium dioxide sol for a period of time, and allowing titanium dioxide to be assembled onto the surface of the polytetrafluoroethylene membrane through the coordination effect of metal titanium-ion Ti4+ and a carboxyl group on the polyacrylic acid so as to obtain a hydrophilic modified polytetrafluoroethylene membrane. The hydrophilic modified polytetrafluoroethylene membrane prepared by using the method in the invention retains excellent properties of a conventional polytetrafluoroethylene membrane and greatly improves filter performance, hydrophilic property, pollution resistant property and photocatalytic property of the polytetrafluoroethylene membrane.

Description

technical field [0001] The invention relates to chemical methods, in particular to a method for hydrophilic modification of polytetrafluoroethylene membranes. Background technique [0002] As a comprehensive and strong material, polytetrafluoroethylene (PTFE) has the reputation of "Plastic King", and is widely used because of its good high and low temperature adaptability, chemical corrosion resistance and excellent mechanical properties. Aerospace, petrochemical, machinery, electronics, construction, textiles and many other fields. The PTFE flat membrane is prepared by biaxially stretching the PTFE dispersion to form micropores. The obtained microporous membrane not only has high porosity, but also has heat resistance, cold resistance and chemical corrosion resistance, which overcomes the chemical resistance of many membrane materials. The defects of pharmaceuticals make PTFE an ideal substrate for preparing high-performance microporous membranes. [0003] In recent years...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/78B01D69/02B01D67/00C02F1/44
Inventor 迟莉娜钱颖佳于振江
Owner 深圳市新纳捷科技有限公司
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