Preparation method of polyolefin hollow fiber membrane

Abstract

The invention provides a preparation method of a polyolefin hollow fiber membrane, which comprises the following steps: preparing a membrane casting solution, and extruding the membrane casting solution through a die head to form a molded product with an inner surface and an outer surface, performing split-phase curing on the molded product at a certain cooling rate; carrying out quenching and extraction treatment to obtain an original film; the original membrane comprises a supporting layer and a separation layer, the separation layer is provided with holes, and the average hole diameter of the separation layer is 5-60 nm; the original membrane is placed in an environment with the temperature not higher than 50 DEG C for low-temperature drying treatment, so that the content of extract liquor in the original membrane is not higher than 5%; and finally, carrying out high-temperature setting to prepare the hollow fiber membrane with high gas mass transfer rate. According to the preparation method, the extraction liquid can be removed within a short time, the integrity of the hollow fiber membrane can be guaranteed, the hole collapse phenomenon is avoided, the prepared hollow fiber membrane has the high gas mass transfer rate, and the preparation method is rapid, effective, easy to operate and suitable for large-scale popularization.

Description

technical field [0001] The invention relates to the technical field of membrane materials, in particular to a preparation method of a polyolefin hollow fiber membrane. Background technique [0002] In many applications in the fields of chemistry, biochemistry or medicine, there is the problem of separating gas components from liquids or adding these components to liquids. For these gas exchange processes, membranes are increasingly used as separation membranes between various liquids and fluids that adsorb or release gaseous components from which gaseous components are separated or added. The fluid here can be a gas or a liquid containing or adsorbing the gas components to be exchanged. Using such membranes, an exchange surface can be provided for gas exchange and, if necessary, direct contact between liquid and fluid can be avoided. [0003] An important application of membrane-based gas exchange methods in the medical field is oxygenators, also called artificial lungs, i...

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Problems solved by technology

[0004] Most of the hollow fiber membranes currently used in oxygenators are asymmetric membranes, which include a separation layer and a support layer, wherein the support layer is located on the side of the hollow fiber membrane close to the inner diameter, and the separation layer is located on the side of the hollow fiber membrane away from the inner diameter; the support The layer has a high porosity, which ensures that oxygen and carbon dioxide can pass through the hollow fiber membrane relatively freely, that is, the CO of the hollow fiber membrane 2 Mass transfer rate and O 2 The mass transfer rate is high; while the separation layer is a dense layer, that is, there are almost no holes on the surface and inside of the separation layer, which ensures that the hollow fiber membrane has a longer plasma penetration time and a longer service life; but the above membrane structure also exists There are some disadvantages, for example, in the preparation process of the hollow fiber membrane, because the separation layer has no holes, the extract is not easy to remove from the hollow fiber membrane in a short time, but if the extract is not removed, the subsequent heat setting treatment cannot be carried out , to get the ideal hollow fiber membrane, so it is necessary to remove the extract; the most effective way to remove the extract in a short time is high-temperature drying. The liquid is removed from the hollow fiber membrane, and the hollow fiber membrane can be heat-set; but high temperature drying is also easy to cause certain damage to the membrane pore structure of the hollow fiber membrane, for example, the holes in the support layer are prone to partial collapse, which affects The integrity of the hollow fiber membrane reduces the gas (oxygen and carbon dioxide) mass transfer rate of the hollow fiber membrane; how to remove the extract in a short time and ensure the integrity of the hollow fiber membrane without collapse, The hollow fiber membrane has a high gas mass transfer rate; the existence of this problem has been plagued by the research and development personnel of the hollow fiber membrane, and it has also limited the development of the hollow fiber membrane to a certain extent.

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