阅读说明：本技术 一种多层聚四氟乙烯中空纤维膜的制备方法 (Preparation method of multilayer polytetrafluoroethylene hollow fiber membrane ) 是由 陈伟 于 2021-09-06 设计创作，主要内容包括：本发明属于新材料技术领域,尤其是一种多层聚四氟乙烯中空纤维膜的制备方法。步骤包括：将聚四氟乙烯分散树脂、助挤剂、纳米二氧化硅、纳米石墨烯、偶联剂、芳纶纤维以及玻璃纤维按比例混合均匀,形成聚四氟乙烯物料；物料挤压形成聚四氟乙烯中空管；然后将聚四氟乙烯中空管进行拉伸和150-160℃低温烧结30-40s热定型,制备成聚四氟乙烯中空纤维膜；浸渍于由聚四氟乙烯分散树脂、水和乙醇组成的涂覆浸渍液中,浸渍后150-160℃下低温烧结20-30s,重复浸渍和低温烧结3～5次；最后置于亲水稳定剂与乙醇体积比为1:1的混合溶液中处理,干燥,得到具有多层膜结构的聚四氟乙烯中空纤维膜,具有优异的抗污染性和高通量性能。(The invention belongs to the technical field of new materials, and particularly relates to a preparation method of a multilayer polytetrafluoroethylene hollow fiber membrane. The method comprises the following steps: uniformly mixing polytetrafluoroethylene dispersion resin, an extrusion aid, nano silicon dioxide, nano graphene, a coupling agent, aramid fiber and glass fiber in proportion to form a polytetrafluoroethylene material; extruding the materials to form a polytetrafluoroethylene hollow tube; then stretching the polytetrafluoroethylene hollow tube and sintering at the low temperature of 150-160 ℃ for 30-40s for heat setting to prepare the polytetrafluoroethylene hollow fiber membrane; dipping the mixture in a coating dipping solution consisting of polytetrafluoroethylene dispersion resin, water and ethanol, sintering the mixture at a low temperature of 160 ℃ for 20 to 30 seconds after dipping, and repeating dipping and low-temperature sintering for 3 to 5 times; and finally, treating the polytetrafluoroethylene hollow fiber membrane in a mixed solution of a hydrophilic stabilizer and ethanol in a volume ratio of 1:1, and drying to obtain the polytetrafluoroethylene hollow fiber membrane with a multilayer membrane structure, which has excellent anti-pollution performance and high flux performance.)

1. A preparation method of a multilayer polytetrafluoroethylene hollow fiber membrane is characterized by comprising the following steps:

(1) mixing materials: uniformly mixing polytetrafluoroethylene dispersion resin, an extrusion aid, nano silicon dioxide, nano graphene, a coupling agent, aramid fiber and glass fiber in proportion to form a polytetrafluoroethylene material;

(2) compacting, extruding and low-temperature sintering: pressing the polytetrafluoroethylene material obtained in the step (1) on a briquetting machine to form a blank, and extruding the blank through a pushing and pressing machine to form a polytetrafluoroethylene hollow tube; then stretching the polytetrafluoroethylene hollow tube and sintering at the low temperature of 150-160 ℃ for 30-40s for heat setting to prepare the polytetrafluoroethylene hollow fiber membrane;

(3) diluting polytetrafluoroethylene dispersion resin with purified water and ethanol to obtain coating impregnation liquid, impregnating the polytetrafluoroethylene hollow fiber membrane shaped in the step (2) into the coating impregnation liquid, then sintering the polytetrafluoroethylene hollow fiber membrane at the low temperature of 150-160 ℃ for 20-30s, and repeating impregnation and low-temperature sintering for a plurality of times to obtain the treated polytetrafluoroethylene hollow fiber membrane;

(4) surface hydrophilic stabilizer treatment: and (4) treating the treated polytetrafluoroethylene hollow fiber membrane obtained in the step (3) in a mixed solution of a hydrophilic stabilizer and ethanol, and then drying to obtain the multilayer polytetrafluoroethylene hollow fiber membrane.

2. The preparation method of claim 1, wherein in the step (1), the mass ratio of the polytetrafluoroethylene dispersion resin, the extrusion aid, the nano-silica, the nano-graphene, the coupling agent, the aramid fiber and the glass fiber is 20-60: 1-15: 0.1-10: 2-10: 0.001-5: 1.2-3.6: 0.8-1.

3. The preparation method according to claim 1 or 2, wherein in the step (1), the molecular weight of the polytetrafluoroethylene dispersion resin is 100-900 ten thousand, the average particle size of the nano-silica is 20-50nm, the length of the aramid fiber is 2-2.5mm, the diameter of the filament is 8-10 μm, and the glass fiber is 100-110 mesh glass fiber powder.

4. The method according to claim 1 or 2, wherein in the step (1), the coupling agent is one or more of a DL602 silane coupling agent, a DL171 silane coupling agent, a KH560 silane coupling agent, and a KH792 silane coupling agent.

5. The process according to claim 1 or 2, wherein in the step (1), the extrusion aid is liquid paraffin, petroleum ether or kerosene.

6. The method of claim 1, wherein in step (2), the extrusion rate is 80 to 200 cm/min.

7. The preparation method according to claim 1, wherein in the step (3), the amount ratio of the polytetrafluoroethylene dispersion resin to the purified water to the ethanol in the coating impregnation solution is 10 to 20 g: 10mL of: 10 mL; the times of repeated dipping and low-temperature sintering are 3-5 times.

8. The method according to claim 1, wherein in the step (4), the volume ratio of the hydrophilic stabilizer to the ethanol in the mixed solution of the hydrophilic stabilizer and the ethanol is 1: 1.

Technical Field

The invention belongs to the technical field of new materials, and particularly relates to a preparation method of a multilayer polytetrafluoroethylene hollow fiber membrane.

Background

At present, the global water quality pollution problem is increasingly prominent, the water demand is continuously increased, and particularly, water resources in many areas of China are deficient, which causes serious supply and demand contradictions of water resource supply. Under the background, the water resource recycling is an effective way for solving the contradiction between supply and demand, and the water treatment industry is determined to have the rigid demand attribute in a long time in the future, so that the potential is huge. The membrane method water treatment has the advantages of high effluent quality, direct reuse, stable effluent quality, small occupied area, high automation degree, convenient management and the like, and is popularized and applied in many fields. Polytetrafluoroethylene filter membranes are commonly used for further filtration of high purity water and the like used in the electronics industry, semiconductors, large scale integrated circuit production, and the like.

In plastic compounding, in order to improve the interfacial properties of synthetic resins with inorganic fillers or reinforcing materials, various surface modifiers and fillers are used, and these additives are utilized to obtain good surface quality, strength and filtration properties.

However, many of the polytetrafluoroethylene hollow fiber membranes used at present have many disadvantages in strength, filtration flux and bonding strength.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of a multilayer polytetrafluoroethylene hollow fiber membrane.

(1) Mixing materials: polytetrafluoroethylene dispersion resin, extrusion aid, nano silicon dioxide, nano graphene, coupling agent, aramid fiber and glass fiber are mixed according to the mass ratio of 20-60: 1-15: 0.1-10: 2-10: 0.001-5: 1.2-3.6: 0.8-1, and mixing uniformly to form a polytetrafluoroethylene material;

(2) compacting, extruding and low-temperature sintering: pressing the polytetrafluoroethylene material obtained in the step (1) on a briquetting machine to form a blank, and extruding the blank through a pushing and pressing machine to form a polytetrafluoroethylene hollow tube; then stretching the polytetrafluoroethylene hollow tube and sintering at the low temperature of 150-160 ℃ for 30-40s for heat setting to prepare the polytetrafluoroethylene hollow fiber membrane;

(3) diluting polytetrafluoroethylene dispersion resin with purified water and ethanol to obtain coating impregnation liquid, impregnating the polytetrafluoroethylene hollow fiber membrane shaped in the step (2) into the coating impregnation liquid, then sintering the polytetrafluoroethylene hollow fiber membrane at the temperature of 150-160 ℃ for 20-30s, repeating impregnation and low-temperature sintering for 3-5 times to obtain the treated polytetrafluoroethylene hollow fiber membrane;

(4) surface hydrophilic stabilizer treatment: and (4) placing the treated polytetrafluoroethylene hollow fiber membrane obtained in the step (3) into a mixed solution of a hydrophilic stabilizer and ethanol in a volume ratio of 1:1 for treatment, and then drying to obtain the multilayer polytetrafluoroethylene hollow fiber membrane.

In the step (1), the molecular weight of the polytetrafluoroethylene dispersion resin is 100-900 ten thousand, the average particle size of the nano silicon dioxide is 20-50nm, the length of the aramid fiber is 2-2.5mm, the diameter of the monofilament is 8-10 mu m, and the glass fiber is 100-mesh 110-mesh glass fiber powder.

In the step (1), the coupling agent is one or more of a DL602 silane coupling agent, a DL171 silane coupling agent, a KH560 silane coupling agent and a KH792 silane coupling agent.

In the step (1), the extrusion aid is liquid paraffin, petroleum ether or kerosene.

In the step (2), the extrusion speed is 80-200 cm/min.

In the step (3), in the coating impregnation liquid, the use amount ratio of polytetrafluoroethylene dispersion resin, purified water and ethanol is 10-20 g: 10mL of: 10 mL.

The invention has the beneficial effects that:

(1) the polytetrafluoroethylene PTFE has the performances of strong acid and strong alkali corrosion resistance and high temperature resistance, so the nanofiltration membrane can be used for treating wastewater in harsh environments such as strong acid and strong alkali, high temperature and the like.

(2) According to the invention, the graphene has a synergistic effect, so that a stronger adsorption effect can be generated, and the adsorption and filtration efficiency of sewage containing sewage is improved.

(3) Due to the high strength and rigidity and good thermal conductivity of the fibers, the aramid fibers and the glass fibers are compounded into the PTFE matrix by utilizing the advantages, so that the friction performance and the mechanical performance of the polymer PTFE are improved. When the matrix is in contact with other materials to generate friction and generate abrasion, the fibers can play a good bearing role and can form a uniform and continuous transfer film on the surface of a mating part, so that the abrasion resistance of the composite material is obviously improved.

(4) The polytetrafluoroethylene hollow fiber membrane with the multilayer membrane structure is obtained through multiple times of dipping and low-temperature sintering, and the surface of the polytetrafluoroethylene hollow fiber membrane is treated by the hydrophilic stabilizer, so that the prepared polytetrafluoroethylene hollow fiber membrane has the advantages of high filtration precision, high filtration flux and high strength, has excellent pollution resistance and high flux performance, and does not have the phenomena of reduced filtration flow rate and flux and reduced filtration performance due to the blocking of membrane pores by particles in the process of filtering particles.

Detailed Description

The present invention will be further described with reference to the following specific examples, but the scope of the present invention is not limited thereto.

Example 1

(1) Mixing materials: polytetrafluoroethylene dispersion resin with the molecular weight of 100-900 ten thousand, extrusion aid liquid paraffin, nano silicon dioxide with the average particle size of 20-50nm, nano graphene, coupling agent DL602, aramid fiber with the length of 2-2.5mm and 100-mesh 110-mesh glass fiber powder are mixed according to the mass ratio of 20: 1: 0.1: 2: 0.001: 1.2: 0.8, mixing uniformly to form a polytetrafluoroethylene material;

(2) compacting, extruding and low-temperature sintering: pressing the polytetrafluoroethylene material obtained in the step (1) on a briquetting machine to form a blank, and extruding the blank through a pushing and pressing machine to form a polytetrafluoroethylene hollow tube; the extrusion speed was 80 cm/min; then stretching the polytetrafluoroethylene hollow tube and sintering at the low temperature of 150 ℃ for 30-40s for heat setting to prepare a polytetrafluoroethylene hollow fiber membrane;

(3) according to the dosage ratio of polytetrafluoroethylene dispersion resin, purified water and ethanol of 10 g: 10mL of: diluting polytetrafluoroethylene dispersion resin by using purified water and ethanol to obtain coating impregnation liquid, impregnating the polytetrafluoroethylene hollow fiber membrane shaped in the step (2) into the coating impregnation liquid, then sintering the polytetrafluoroethylene hollow fiber membrane at the low temperature of 150 ℃ for 20-30s, repeating impregnation and low-temperature sintering for 3-5 times to obtain the treated polytetrafluoroethylene hollow fiber membrane;

(4) surface hydrophilic stabilizer treatment: and (4) placing the treated polytetrafluoroethylene hollow fiber membrane obtained in the step (3) into a mixed solution of a hydrophilic stabilizer and ethanol in a volume ratio of 1:1 for treatment, and then drying to obtain the multilayer polytetrafluoroethylene hollow fiber membrane.

Example 2

(1) Mixing materials: polytetrafluoroethylene dispersion resin with the molecular weight of 100-900 ten thousand, extrusion aid petroleum ether, nano silicon dioxide with the average particle size of 20-50nm, nano graphene, coupling agent DL171, aramid fiber with the length of 2-2.5mm and 100-mesh 110-mesh glass fiber powder are mixed according to the mass ratio of 40: 10: 5: 6: 1: 2: 0.9, mixing uniformly to form a polytetrafluoroethylene material;

(2) compacting, extruding and low-temperature sintering: pressing the polytetrafluoroethylene material obtained in the step (1) on a briquetting machine to form a blank, and extruding the blank through a pushing and pressing machine to form a polytetrafluoroethylene hollow tube; the extrusion speed was 100 cm/min; then stretching the polytetrafluoroethylene hollow tube and sintering at 155 ℃ for 30-40s for heat setting to prepare a polytetrafluoroethylene hollow fiber membrane;

(3) according to the dosage ratio of polytetrafluoroethylene dispersion resin, purified water and ethanol of 15 g: 10mL of: diluting polytetrafluoroethylene dispersion resin by using purified water and ethanol to obtain coating impregnation liquid, impregnating the polytetrafluoroethylene hollow fiber membrane shaped in the step (2) into the coating impregnation liquid, then sintering the polytetrafluoroethylene hollow fiber membrane at the low temperature of 155 ℃ for 20-30s, repeating impregnation and low-temperature sintering for 3-5 times to obtain the treated polytetrafluoroethylene hollow fiber membrane;

(4) surface hydrophilic stabilizer treatment: and (4) placing the treated polytetrafluoroethylene hollow fiber membrane obtained in the step (3) into a mixed solution of a hydrophilic stabilizer and ethanol in a volume ratio of 1:1 for treatment, and then drying to obtain the multilayer polytetrafluoroethylene hollow fiber membrane.

Example 3

(1) Mixing materials: polytetrafluoroethylene dispersion resin with the molecular weight of 100-900 ten thousand, extrusion aid kerosene, nano silicon dioxide with the average particle size of 20-50nm, nano graphene, a coupling agent KH560, aramid fiber with the length of 2-2.5mm and 100-mesh 110-mesh glass fiber powder are mixed according to the mass ratio of 60: 15: 10: 10: 5: 3.6: 1, uniformly mixing to form a polytetrafluoroethylene material;

(2) compacting, extruding and low-temperature sintering: pressing the polytetrafluoroethylene material obtained in the step (1) on a briquetting machine to form a blank, and extruding the blank through a pushing and pressing machine to form a polytetrafluoroethylene hollow tube; the extrusion speed was 200 cm/min; then stretching the polytetrafluoroethylene hollow tube and sintering at the low temperature of 160 ℃ for 30-40s for heat setting to prepare a polytetrafluoroethylene hollow fiber membrane;

(3) according to the dosage ratio of polytetrafluoroethylene dispersion resin, purified water and ethanol of 20 g: 10mL of: diluting polytetrafluoroethylene dispersion resin by using purified water and ethanol to obtain coating impregnation liquid, impregnating the polytetrafluoroethylene hollow fiber membrane shaped in the step (2) into the coating impregnation liquid, then sintering the polytetrafluoroethylene hollow fiber membrane at the low temperature of 160 ℃ for 20-30s, repeating impregnation and low-temperature sintering for 3-5 times to obtain the treated polytetrafluoroethylene hollow fiber membrane;

(4) surface hydrophilic stabilizer treatment: and (4) placing the treated polytetrafluoroethylene hollow fiber membrane obtained in the step (3) into a mixed solution of a hydrophilic stabilizer and ethanol in a volume ratio of 1:1 for treatment, and then drying to obtain the multilayer polytetrafluoroethylene hollow fiber membrane.

The water flux of the multilayer polytetrafluoroethylene hollow fiber membranes prepared in the embodiments 1-3 is detected, and the change condition of the water flux after continuous operation for 24 hours is considered, and is only reduced by 1-2%.

The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.