阅读说明：本技术 一种对称结构的聚醚砜中空纤维超滤膜及其制备方法 (Polyether sulfone hollow fiber ultrafiltration membrane with symmetrical structure and preparation method thereof ) 是由 白静娜 韩永良 石江波 刘丽研 于 2020-04-27 设计创作，主要内容包括：本发明公开了一种对称结构的聚醚砜中空纤维超滤膜及其制备方法；本发明的聚醚砜中空纤维超滤膜分别由内外双过滤层皮层和中间海绵体支撑层三个部分组成,其中,内外过滤层均具有0.003-0.06μm的分离孔径,海绵结构平均分离孔径为0.035μm,孔径分布非常窄；制备方法为三个步骤：以三缩四乙二醇(TEG)为不良溶剂,聚乙烯吡咯烷酮(PVP)为致孔剂,二甲基乙酰胺(DMAC)或N,N-二甲基甲酰胺(DMF)为溶剂,配制聚醚砜均相膜液；通过纺丝工艺制得PES中空纤维超滤初膜；再通过后处理：水洗-甘油浸泡-晾干可得。所制得膜渗透性强、过滤精度高,制备方法简单,适用于各种工业领域及纳滤基膜。(The invention discloses a polyether sulfone hollow fiber ultrafiltration membrane with a symmetrical structure and a preparation method thereof; the polyether sulfone hollow fiber ultrafiltration membrane is composed of an inner filtering layer skin layer, an outer filtering layer skin layer and a middle sponge body supporting layer, wherein the inner filtering layer and the outer filtering layer are respectively provided with a separation pore diameter of 0.003-0.06 mu m, the average separation pore diameter of a sponge structure is 0.035 mu m, and the pore diameter distribution is very narrow; the preparation method comprises three steps: preparing a polyether sulfone homogeneous membrane liquid by using tetraethylene glycol (TEG) as a poor solvent, polyvinylpyrrolidone (PVP) as a pore-forming agent and Dimethylacetamide (DMAC) or N, N-Dimethylformamide (DMF) as a solvent; preparing a PES hollow fiber ultrafiltration primary membrane by a spinning process; and then carrying out post-treatment: washing with water, soaking in glycerol, and air drying. The prepared membrane has strong permeability, high filtration precision and simple preparation method, and is suitable for various industrial fields and nanofiltration base membranes.)

1. A polyethersulfone hollow fiber ultrafiltration membrane with a symmetrical structure is characterized in that: consists of three parts, namely an inner filtering layer skin layer, an outer filtering layer skin layer and a middle sponge supporting layer.

2. The polyethersulfone hollow fiber ultrafiltration membrane with a symmetrical structure as claimed in claim 1, wherein: the inner and outer filtering layers have a separating pore diameter of 0.003-0.06 μm, the three-dimensional network sponge structure has a separating pore diameter of 0.01-0.1 μm, and the average pore diameter is 0.035 μm.

3. According to claim2 the polyethersulfone hollow fiber ultrafiltration membrane with the symmetrical structure is characterized in that: the PES hollow fiber ultrafiltration membrane with the symmetrical structure has the membrane silk pure water flux under 0.1MPa>500LMH, tensile Strength>450cN/mm²Strength of blast>1MPa。

4. The preparation method of the polyether sulfone hollow fiber ultrafiltration membrane with the symmetrical structure according to any one of claims 1 to 3, which is characterized by comprising the following steps of: comprises the following steps

(1) Preparing a homogeneous membrane liquid: setting the temperature to be 60 ℃, stirring and dissolving polyether sulfone and a solvent, cooling to 40 ℃, then adding polyvinylpyrrolidone and tetraethylene glycol, stirring and dissolving at the stirring speed of 50r/min for 10-24h, and defoaming in vacuum;

(2) preparing a primary membrane: the spinning temperature of the homogeneous membrane liquid is 30-45 ℃; the components of the internal coagulating bath are as follows: 0-20% DMF in water; the external coagulation bath component is 10-50% DMF water solution; extruding the membrane liquid from a spinning jet, and then entering a pre-evaporation air bath which is 30-80mm away from an external coagulation bath, wherein the relative humidity is 40-80%, the set temperature is 30-40 ℃, and the stretching speed is 15-20m/min, so as to prepare a PES hollow fiber ultrafiltration primary membrane;

(3) and (3) post-treatment: and (3) putting the PES hollow fiber ultrafiltration primary membrane prepared in the step (2) into a water washing tank, rinsing with RO water for 24 hours, soaking membrane filaments in 30-50% glycerol aqueous solution for 24 hours, airing and storing for later use.

5. The preparation method of the polyether sulfone hollow fiber ultrafiltration membrane with the symmetrical structure according to claim 4, which is characterized by comprising the following steps of: the corresponding components and parts by weight in the step 1 are as follows: PES: 19 parts and PVP: 5-6 parts of TEG: 16-23 parts, DMAC/DMF: 52-59 parts.

6. The preparation method of the polyether sulfone hollow fiber ultrafiltration membrane with the symmetrical structure according to claim 5, which is characterized by comprising the following steps of: the corresponding components and parts by weight in the step 1 are as follows: PES: 19 parts and PVP: 5-6 parts of TEG: 18-20 parts of DMAC: 57-59 parts.

Technical Field

The invention relates to a macromolecular ultrafiltration membrane and a preparation method thereof, in particular to a polyether sulfone hollow fiber ultrafiltration membrane with a symmetrical structure and a preparation method thereof.

Background

Polyether sulfone (PES) is a thermoplastic polymer material with excellent comprehensive performance, is one of a few special engineering plastics, has the characteristics of excellent heat resistance, physical and mechanical properties, insulating property and the like, particularly has the outstanding advantages of continuous use at high temperature, stable performance in an environment with rapid temperature change and the like, and is widely applied in many fields.

Disclosure of Invention

The invention aims to solve the problems in the background technology, and provides a polyethersulfone hollow fiber ultrafiltration membrane with a symmetrical structure and a preparation method thereof.

The invention relates to a PES hollow fiber ultrafiltration membrane with a symmetrical structure, which is characterized by consisting of an inner filtering layer skin layer, an outer filtering layer skin layer and a middle sponge supporting layer.

Furthermore, the inner and outer filter layers of the PES hollow fiber ultrafiltration membrane with the symmetrical structure are respectively provided with a separation pore diameter of 0.003-0.06 mu m, the separation pore diameter of the three-dimensional network sponge structure is 0.01-0.1 mu m, and the average pore diameter is 0.035 mu m.

Furthermore, the PES hollow fiber ultrafiltration membrane with the symmetrical structure has membrane filaments and pure water flux under 0.1MPaMeasurement of>500LMH, tensile Strength>450cN/mm²Strength of blast>1MPa。

The invention also provides a preparation method of the polyether sulfone hollow fiber ultrafiltration membrane with the symmetrical structure, which comprises the following steps:

step one, preparing a homogeneous phase membrane liquid: setting the temperature to be 60 ℃, stirring and dissolving polyether sulfone and a solvent, cooling to 40 ℃, then adding polyvinylpyrrolidone and tetraethylene glycol, continuously stirring and dissolving at a stirring speed of 50r/min for 10-24h, and defoaming in vacuum; wherein the solvent is DMAC or DMF, and the corresponding components and parts by weight are as follows: PES: 19 parts, DMAC/DMF: 52-59 parts of PVP: 5-6 parts of TEG: 16-23 parts.

Step two, primary membrane preparation: the spinning temperature of the homogeneous membrane liquid is 30-45 ℃; the components of the internal coagulating bath are as follows: 0-20% DMF in water; the external coagulation bath component is 10-50% DMF water solution; extruding the membrane liquid from a spinning nozzle of a double-ring flow channel, feeding the membrane liquid into a pre-evaporation air bath, wherein the distance between the membrane liquid and an external coagulation bath is 30-80mm, the relative humidity is 40-80%, the set temperature is 30-40 ℃, and the stretching speed is 15-20m/min, so as to prepare a PES hollow fiber ultrafiltration primary membrane;

thirdly, post-treatment: and (3) putting the PES hollow fiber ultrafiltration primary membrane prepared in the step (2) into a water washing tank, rinsing with RO water for 24 hours, soaking membrane filaments in 30-50% glycerol aqueous solution for 24 hours, airing and storing to obtain the PES hollow fiber ultrafiltration primary membrane.

Preferably, in the step 1, the homogeneous phase membrane liquid comprises the following components in parts by weight: PES: 19 parts and PVP: 5-6 parts of TEG: 18-20 parts of DMAC: 57-59 parts.

Wherein, the spinning temperature of the homogeneous membrane liquid in the step 2 is set to be 30-45 ℃, because the viscosity of the membrane liquid system is sharply increased when the temperature is lower than 30 ℃, the discharging is easy to be uneven, and the porosity of the membrane yarn is reduced; and when the temperature in the spinning process is >45 ℃: solid-liquid phase separation occurs due to thermodynamic imbalance of a homogeneous system near the phase separation point.

The invention has prominent substantive features and remarkable progress, in particular: in the invention, TEG is used as a poor solvent, PVP is used as a pore-forming agent, and DMAC or DMF is used as a solvent to prepare the polyether sulfone homogeneous phase membrane liquid, wherein the dissolution state of the membrane liquid is close to the liquid-liquid phase separation critical point. In a PES/PVP/DMF system, after a poor solvent TEG is added in a certain proportion, a polymer PES molecular chain segment develops from a stretching state to a curling and tangling state and is in a thermodynamic equilibrium state, if the TEG is continuously added, the equilibrium state of the system is damaged, and a membrane liquid suddenly turns turbid from transparent to generate liquid-liquid phase separation. In a proper temperature range, when the membrane liquid at the phase separation critical point enters a coagulating bath, the phase is rapidly separated from the inner surface and the outer surface to the center, the mass transfer exchange of a solvent and a non-solvent of the coagulating bath is completed, in the process, a large number of micropores are solidified in time of growth, and uniform sponge micropores with high porosity are generated.

The PES hollow fiber ultrafiltration membrane with the symmetrical structure can optimize the structure and the performance of the membrane by finely adjusting spinning process conditions, such as the composition and the temperature of a coagulation bath inside and outside the membrane liquid, the air bath time and humidity, the stretching speed and the like, so that the permeability of the membrane can be fully ensured; the prepared membrane consists of an inner filtering layer skin layer, an outer filtering layer skin layer and a middle sponge supporting layer respectively; the inner and outer filtering layers have a separation aperture of 0.003-0.06 μm, the three-dimensional network sponge structure has a separation aperture of 0.01-0.1 μm, an average aperture of 0.035 μm, narrow aperture distribution, simple method, and suitability for various industrial fields and preparation of nanofiltration base membranes.

Drawings

FIG. 1 is a scanning electron micrograph of a cross section of a hollow fiber ultrafiltration membrane at 50 times magnification.

FIG. 2 is a scanning electron micrograph of a cross section of a hollow fiber ultrafiltration membrane magnified 300 times.

FIG. 3 is a scanning electron microscope image of a cross-section sponge support layer of a hollow fiber ultrafiltration membrane magnified 10000 times.

FIG. 4 is a scanning electron microscope image of the outer skin layer of a hollow fiber ultrafiltration membrane at 10000 times magnification.

Detailed Description

The following is a detailed description of one embodiment of the invention, but the description is only a preferred embodiment of the invention and should not be taken as limiting the scope of the invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.