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Preparation method of polytetra fluorethylene hydrophilic micro filtering membrane

A polytetrafluoroethylene, hydrophilic technology, used in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve problems such as membrane flux decline, and achieve easy backwashing, increased output, and low resistance. Effect

Inactive Publication Date: 2006-06-14
LISHUI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The microfiltration membrane made by PTFE stretching method has very good thermal stability and chemical stability, and has advantages in electronics, food, medical, biological products and other industries, but the PTFE microfiltration membrane made directly by stretching method has strong Hydrophobic, so its application is greatly limited. First, in order to allow water to pass through the membrane pores, it must have a high driving force (for example, a PTFE membrane with a pore size of 0.2 μm cannot allow water to pass through under the action of a pressure difference of 0.01MPa. Membrane pores); secondly, the membrane is easily contaminated by protein adsorption, resulting in a rapid decrease in membrane flux

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] After blending 99.5% (mass percentage, the same below) polytetrafluoroethylene resin and 0.5% polyvinyl alcohol, it is biaxially stretched to form a film, set at 270 ° C for 15 seconds, and then activated with 1% activator Then prepare the film.

[0017] First prepare PTFE fine powder with a molecular weight of 5 to 6 million, dry it at 120°C for 10 hours, and then sieve it, then blend it with 0.5% of polyvinyl alcohol fine powder (dried and sieved) with similar molecular weight, and then pass through two-way Stretch to form a film, and set it at a temperature of 270° C. for 15 seconds after film formation. Polyvinyl alcohol (PVA) has strong hydrophilicity, and blending with PTFE can improve the hydrophilicity of PTFE membrane, but two problems need to be solved. First, the compatibility problem of PTFE and PVA should be solved. The good hydrophilicity of the membrane while reducing the amount of PVA as much as possible is also beneficial to maintaining the excellent p...

Embodiment 2

[0019] The 100% polytetrafluoroethylene resin is biaxially stretched to form a film, fixed at a temperature of 390°C for 30 seconds, and then activated with 5% activator to prepare a film.

[0020] The PTFE fine powder with a molecular weight of 5 to 6 million is biaxially stretched to form a film, and after the film is formed, it is set at a temperature of 390°C for 30 seconds. Then use 5% (mass percentage) activator to carry out activation treatment, make the surface of the membrane pores absorb hydrophilic groups, and improve the hydrophilicity of the membrane. After the activation treatment, the PTFE membrane is dried to become the finished membrane. Finished membrane performance: the average pore diameter of the membrane is 0.2 μm to 10 μm (the pore size is related to the stretching degree of the membrane, that is, the thickness of the membrane), and the water flux is 1.0ml / cm 2 ·min (ΔP0.01MPa, 25°C) or more.

Embodiment 3

[0022] After blending 95% (mass percentage, the same below) polytetrafluoroethylene resin and 5% polyvinyl alcohol to form a film through biaxial stretching, set it at a temperature of 500 ° C for 0.1 second, heat it with a polypropylene porous support film Composite, and then activated with 2% activator to prepare a composite film.

[0023] First prepare 95% PTFE fine powder with a molecular weight of 5 to 6 million, dry at 120°C for 10 hours and sieve, then mechanically blend with 5% of polyvinyl alcohol fine powder (dried and sieved) with similar molecular weight, and then It is formed into a film by biaxial stretching. After the film is formed, it is set at a temperature of 500°C for 0.1 second, and thermally compounded with a polypropylene porous support film to form a composite film. Then use 2% activator to carry out activation treatment, so that the hydrophilic groups contained in the PVA are exposed on the surface of the membrane pores as much as possible, and the hyd...

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Abstract

A hydrophilic microfiltering teflon membrane is prepared from teflon resin (95-100 mass%) and PVA (0-5) through mixing, bidirectional stretching to become membrane, fixing its shape at 270-500 deg.C and activiating. It has high hydrophilicity and water permeability.

Description

technical field [0001] The invention relates to a preparation method of a polytetrafluoroethylene hydrophilic microfiltration membrane, in particular, the invention relates to a method for liquid filtration in the fields of chemical industry, medicine, food, water purification, textile, metallurgy, mining, environmental protection, etc. Preparation method of new polytetrafluoroethylene hydrophilic microfiltration membrane. Background technique [0002] Polytetrafluoroethylene (hereinafter referred to as PTFE), commonly known as the king of plastics, has excellent physical and chemical properties such as high and low temperature resistance, strong acid and alkali resistance, and oxidation resistance. The microfiltration membrane made by PTFE stretching method has very good thermal stability and chemical stability, and has advantages in electronics, food, medical, biological products and other industries, but the PTFE microfiltration membrane made directly by stretching method...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/36
Inventor 蒋新龙
Owner LISHUI UNIV
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