Multi-core hollow fiber porous membrane and preparation method thereof

Abstract

The invention discloses a multi-core hollow fiber porous membrane and a preparation method thereof and relates to a polymer. The multi-core hollow fiber porous membrane is provided with at least two hollow fiber membrane bundles, the outer diameter of a single hollow fiber membrane is 0.2-3mm, the wall thickness of the single hollow fiber membrane is 0.05-1mm, the porosity is 50%-90%, the membrane separation pore size is 0.01-1 mu m, the rupture strength is 0.3-2MPa, the tension fracture tension of the hollow fiber membrane bundles is 0.2-10.0kg / bundle, and the pure water flux is 600-10000L / m2.h at 0.1MPa and 25 DEG C. The dry-wet non-solvent induced phase separation (NIPS) spinning process is adopted for enabling polymer casting solution and spinning core solution to simultaneously pass through a spinning spray head for forming nascent hollow fibers, and 2-8 single nascent hollow fibers are gathered into one bundle before entering into a coagulation bath water tank, and further enter into the coagulation bath water tank for forming the bundle-like hollow fiber membrane.

Description

technical field [0001] The invention relates to a polymer, in particular to a multi-core hollow fiber porous membrane which can be used to manufacture external pressure polymer hollow fibers and a preparation method thereof. Background technique [0002] Hollow fiber membranes are mainly used for filtration and separation in various fields. [0003] The formation mechanism of the solution phase transfer hollow fiber membrane is that the membrane-forming polymer, organic solvent, and pore-forming agent are mixed in a certain proportion, and after being dissolved evenly, they enter the coagulation bath through the spinning nozzle. The solvent and pore-forming agent in the polymer solution enter the coagulant phase, and the polymer precipitates into a polymer hollow fiber membrane due to phase transfer. A hollow fiber separation membrane with a certain pore size can be obtained by controlling the spinning stock solution formula, spinning process parameters and hollow fiber pos...

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Problems solved by technology

The rupture strength of the product obtained by this method is insufficient, and the penetration rate of pure water is relatively slow, which cannot meet the needs

[0006] 2. In Japanese Patent Publication No. 3-71168, a preparation method of adding 7.2wt% polyethylene glycol as a pore-forming agent is described, but a membrane with high permeation flux has not yet been obtained

[0011] 1. The outer diameter of the thin tube membrane is larger, and the packing density per unit volume is lower than that of the hollow fiber membrane

[0012] 2. Since the combination of the braided support tube and the porous membrane material is not strong enough, the dope from spinning only adheres to the outer side of the braid, and does not penetrate into the inner wall of the braid. When the membrane is backwashed after contamination, it is easy to cause the braided support tube to bond with the porous membrane material. Peeling damage phenomenon of porous membrane materials, especially in alkaline environment

[0013] 3. When the air vibration cleaning method is used, the membrane material is prone to fatigue, damage and peeling at the junction of the thin tube membrane root and the casting resin

[0014] Chinese patent CN169577A introduces the production technology of three fiber filaments reinforced polyvinylidene fluoride hollow fiber membranes, but since there are only three filaments in the membrane filaments, the radial mechanical properties of the membrane filaments are very different, resulting in the membrane filaments being subjected to pressure from outside to inside. Irreversible damage occurs when the impact force from inside to outside

[0015] Chinese patent 1583232A provides a kind of spinning dope that utilizes weight-average molecular weight polyvinylidene fluoride resin and a high proportion of organic additives to change the internal sponge-like support structure of the hollow fiber membrane, although it can improve the compression resistance of the membrane However, the tensile strength of the membrane filament cannot meet the application fields with a high degree of pollution.

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