Super hydrophobic polytetrafluoroethylene hollow fiber membrane preparation method

A water polytetrafluoroethylene and polytetrafluoroethylene technology, which is applied in the field of preparation of hollow fiber membranes, can solve the problems of PET fiber braided tubes being easily wetted by water and the quality of water produced by membrane distillation, etc., and achieves great practical value, The effect of low cost and simple method

Active Publication Date: 2014-12-31
ZHEJIANG SCI-TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Patent CN102284251A prepares polytetrafluoroethylene hollow fiber membranes by continuously wrapping polytetrafluoroethylene flat membranes on polyester (PET) fiber braided tube supports, but this method uses PET fiber braided tubes with poor hydrophobicity as support During the long-term high-temperature distillation process, the PET fiber braided tube is easily wetted by water, which leads to a great decrease in the quality of membrane distillation water.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] a) Mixing: Select polytetrafluoroethylene dispersion resin powder with a molecular weight of 2 million, mix polytetrafluoroethylene dispersion resin powder and liquid paraffin evenly at a mass ratio of 1:0.22, and let stand at 20°C for 60 hours to make PTFE dispersed resin powder is fully mixed with liquid paraffin to form PTFE material;

[0022] b) Compacting and extrusion: Press the polytetrafluoroethylene material on a compacting machine to form a cylindrical blank, pass the cylindrical blank through a pusher, and extrude it at 100°C to form a polytetrafluoroethylene hollow tube , the extrusion speed is 100 cm / min;

[0023] c) Preparation of silica sol: mix 30% ammonia water and absolute ethanol at a volume ratio of 1:50, stir at 40°C for 20 minutes to form an ammonia-water-ethanol mixture, and then drop at a volume ratio of 1:50 Add ethyl orthosilicate to the ammonia water ethanol mixture, stir at 60°C for 60 minutes to form a silica sol;

[0024] d) Preparation o...

Embodiment 2

[0029] a) Mixing: Select polytetrafluoroethylene dispersed resin powder with a molecular weight of 10 million, mix polytetrafluoroethylene dispersed resin powder with petroleum ether at a mass ratio of 1:0.40, and let stand at 40°C for 80 hours to make PTFE dispersion resin powder is fully mixed with petroleum ether to form PTFE material;

[0030] b) Compacting and extrusion: Press the polytetrafluoroethylene material on a compacting machine to form a cylindrical blank, pass the cylindrical blank through a pusher, and extrude it at 200°C to form a polytetrafluoroethylene hollow tube , the extrusion speed is 300 cm / min;

[0031] c) Preparation of silica sol: Mix 30% ammonia water and absolute ethanol at a volume ratio of 5:50, stir at 40°C for 20 minutes to form an ammonia-water-ethanol mixture, and then drop at a volume ratio of 10:50 Add ethyl orthosilicate to the ammonia water ethanol mixture, stir at 60°C for 120 minutes to form a silica sol;

[0032] d) Preparation of th...

Embodiment 3

[0037] a) Mixing: Select polytetrafluoroethylene dispersed resin powder with a molecular weight of 5 million, mix polytetrafluoroethylene dispersed resin powder and kerosene at a mass ratio of 1:0.30, and let stand at 25°C for 70 hours to make the polytetrafluoroethylene dispersed resin powder Tetrafluoroethylene dispersed resin powder is fully mixed with kerosene to form polytetrafluoroethylene material;

[0038] b) Compacting and extrusion: Press the polytetrafluoroethylene material on a compacting machine to form a cylindrical blank, pass the cylindrical blank through a pusher, and extrude it at 145°C to form a polytetrafluoroethylene hollow tube , the extrusion speed is 150 cm / min;

[0039]c) Preparation of silica sol: Mix 30% ammonia water and absolute ethanol at a volume ratio of 3:50, stir at 40°C for 20 minutes to form an ammonia-water-ethanol mixture, and then drop at a volume ratio of 4:50 Add ethyl orthosilicate to the ammonia water ethanol mixture, stir at 60°C fo...

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Abstract

The invention discloses a super hydrophobic polytetrafluoroethylene hollow fiber membrane preparation method. The method comprises the steps of mixing polytetrafluoroethylene dispersion resin powder with an extruding-aid agent, pressing a blank, extruding the blank into a polytetrafluoroethylene hollow tube through an extruder, then processing modification to the polytetrafluoroethylene hollow tube through silica sol, and then performing vertical stretching, sintering and heat setting in a baking oven, finally performing penetration processing by using perfluorosilane to obtain the super hydrophobic polytetrafluoroethylene hollow fiber membrane. The processed super hydrophobic polytetrafluoroethylene hollow fiber membrane has an average aperture on external layer of between 0.10-1.0 micrometer and an average aperture on internal layer of between 5.0-20 micrometer, and a surface water contact angle of 152-160 degree. The membrane is mainly used in membrane distillation and separation process, and can be used for seawater desalination, industrial waste water processing and in foodstuff and biological product cryoconcentration.

Description

technical field [0001] The invention relates to a preparation method of a hollow fiber membrane, in particular to a preparation method of a superhydrophobic polytetrafluoroethylene hollow fiber membrane. Background technique [0002] Membrane distillation technology is a new type of membrane separation technology that uses the difference in vapor pressure on both sides of a hydrophobic microporous membrane as the driving force for mass transfer. Because membrane distillation technology can repel non-volatile substances in the solution (such as ions, macromolecules and solid particles, etc.), the operating pressure is lower than that of reverse osmosis, the equipment is simple, the requirements for raw water quality are low, and only water vapor passes through the membrane pores. The produced water has the advantages of high purity, which can be used in seawater desalination, deep reuse treatment of industrial wastewater, concentration and crystallization of food and biologic...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/36B01D69/08B01D67/00B01D61/36
Inventor 朱海霖郭玉海陈建勇张华鹏唐红艳
Owner ZHEJIANG SCI-TECH UNIV
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