A kind of preparation method of long fiber reinforced hollow fiber membrane

Abstract

The invention discloses a method for preparing a long fiber reinforced hollow fibrous membrane. The method can be implemented in two ways: (1) adopting a spinning nozzle having a long fiber channel; introducing a long fiber into the long fiber channel; guiding the long fiber into a membrane casting solution and fiber compounding area via a fiber positioning plate; co-extruding the compounded long fiber and membrane casting solution; and forming a membrane under the action of core solution and external coagulating bath or cooling bath, and (2) adopting a spinning nozzle for co-extruding the long fiber and the membrane casting solution; guiding the long fiber out of a liquid material jar; guiding the long fiber to pass by a membrane casting solution pipeline and introducing the long fiber into the spinning nozzle from a membrane casting solution inlet of the spinning nozzle; co-extruding the long fiber and membrane casting solution after positioning the long fiber through the fiber positioning plate; forming the membrane under the action of core solution and external coagulating bath; and finally winding the membrane through a guide wheel and a winding machine. The long fiber reinforced compound membrane prepared by using the method has the advantages that the mechanical strength of the hollow fibrous membrane is increased by 3-5 times according to the quantity and variety of the long fiber in the hollow fibrous membrane, and the water flux, the rejection coefficient and the hydrophilicity are all obviously improved.

Description

technical field [0001] The invention belongs to the technical field of preparation and reinforcement of polymer membrane materials, and in particular relates to a preparation method of long fiber reinforced hollow fiber membranes. Background technique [0002] Due to its large surface area and easy packaging into modules, polymer hollow fiber membranes have been widely used in many separation and concentration fields such as water purification, industrial and municipal sewage treatment, reclaimed water reuse, and biomedical applications. . However, because of the low mechanical strength of the polymer membrane in the usual membrane preparation process, there is a problem that it is prone to breakage during use and cleaning. In order to improve the mechanical strength of hollow fiber membranes, US Patent (US Patent No.5,472,607) discloses a method for preparing composite membranes using fiber braided tubes to reinforce hollow fibers. The membrane method is to coat the casti...

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Problems solved by technology

The hollow fiber membrane prepared by this method is greatly improved in tensile strength, but the hollow fiber composite membrane prepared is only coated with casting solution on the outer layer of the braided tube, and the prepared composite membrane has the following problems: (1) There is less casting solution adhered to the inner layer of the braided tube, and most of the polymer membranes that can act as a separation layer are on the outer layer of the braided tube; (2) Due to the weak bonding force between the casting solution and the fiber braided tube, the During the backwashing process of the hollow fiber composite membrane, it is easy to cause the polymer membrane and the braided tube to fall off; (3) The hollow fiber composite membrane reinforced by the fiber braided tube commonly used is only suitable for external pressure filtration

Similarly, in order to distribute the long fibers in the hollow fiber membrane structure, after the long fibers pass through the fiber positioning plate, an appropriate traction force can also be applied to the fibers in advance, so that the long fibers are positioned in the casting liquid extrusion port, Avoid bending of the long fibers in the casting solution, resulting in weakened strength of the hollow fiber composite membrane

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