CN114887503B - Mixed matrix hollow fiber oxygenation membrane based on framework material and preparation method thereof - Google Patents

Abstract

The invention provides a mixed matrix hollow fiber oxygenation membrane based on a framework material and a preparation method thereof. The method comprises the following steps: (1) weighing materials according to a formula; (2) preparing a mixed matrix membrane casting solution; (3) forming the mixed matrix hollow fiber membrane. The mixed matrix hollow fiber oxygenation membrane is prepared by blending a framework material and a polymer and adopting a non-solvent induced phase separation method (NIPS) based on the characteristics of large specific surface area and rich surface functional groups of the framework material. The addition of the frame material provides an additional transmission channel for the gas and the adsorption characteristic of the frame material to the gas, so that the gas permeability of the membrane is effectively improved, and meanwhile, the complex technological process for regulating and controlling the membrane structure in the current poly (4-methyl-1-pentene) oxygenation membrane production is avoided.

Description

A mixed matrix hollow fiber oxygenation membrane based on frame material and preparation method thereof

Technical Field

The invention belongs to the field of membrane technology, and in particular relates to an application of a mixed matrix hollow fiber oxygenation membrane based on a frame material.

Background technique

Extracorporeal membrane oxygenator is a medical device that enriches venous blood with oxygen and removes carbon dioxide from it, which can temporarily replace the human heart and lung function. It is widely used in lung transplantation, heart surgery and the treatment of patients with severe respiratory failure. The oxygenation membrane is its core component. The permeability, blood compatibility and anti-wetting ability of the oxygenation membrane will directly affect the performance of the oxygenator.

There is no essential difference between oxygenation membranes and gas separation membranes. The main difference is that oxygenation membranes focus on the permeability of oxygen and carbon dioxide, while gas separation membranes focus on the selectivity and separation efficiency of the target gas. Mixed matrix membranes prepared by blending polymers with framework materials have shown strong performance in the field of gas separation. Framework materials have porous structures and large specific surface areas and are widely used in gas transmission and separation. Metal organic frameworks (MOFs) and covalent organic frameworks (COFs) are the two most common types. Hydrogen bonded organic frameworks (HOFs) are a new type of porous framework material formed by organic building units through hydrogen bonding. They do not contain metal ions and have better biocompatibility and low cytotoxicity. The porous structure of the framework material itself is conducive to the permeation of oxygen and carbon dioxide, and specific groups make the pores of the framework material polar, which will interact with the electric quadrupole moment of carbon dioxide and adsorb carbon dioxide to form a high-speed transmission channel for carbon dioxide.

Among the current commercial oxygenation membranes, poly(4-methyl-1-pentene) hollow fiber membranes have the most advantages. Poly(4-methyl-1-pentene) hollow fiber membranes have a porous sponge-like main structure and a dense cortex, which is not prone to plasma leakage, but the gas permeability is relatively poor compared to other materials. In addition, the raw material poly(4-methyl-1-pentene) is difficult to purchase. The polymer characteristics of poly(4-methyl-1-pentene) such as the same density in the crystalline and amorphous regions, different crystallization rules, and irregular crystalline regions make it difficult to regulate its membrane structure. The thermally induced phase separation (TIPS) production process is complex, and the membrane formation process is difficult to control. In addition, the preparation technology of poly(4-methyl-1-pentene) hollow fiber membranes is currently monopolized by 3M.

Therefore, in view of the problems of relatively poor gas permeability, difficult preparation and monopoly of production technology in current commercial oxygenation membranes, the present invention prepares mixed matrix membranes by the NIPS method after blending the framework material with a suitable polymer, which is expected to solve these problems at the same time and promote the development of the field of oxygenation membrane materials.

Summary of the invention

The invention prepares a mixed matrix hollow fiber oxygenation membrane which has good oxygen and carbon dioxide permeability and simple process by blending a frame material with a polymer and forming a membrane by a NIPS method.

The present invention provides a mixed matrix hollow fiber oxygenation membrane based on a frame material and a preparation method thereof, which is characterized by comprising the following steps:

(1) Weighing materials according to the formula, including polymer, solvent 1, plasticizer, and frame material;

(2) first adding some materials including solvent 1, plasticizer and frame material, and performing ultrasonic treatment until they are evenly dispersed, then adding polymer, heating, stirring, standing and degassing to prepare mixed matrix membrane casting solution;

(3) Select a spinneret of appropriate size for spinning, introduce the spinning solution into the coagulation bath solvent 2, and form a mixed matrix hollow fiber membrane by the NIPS method.

Furthermore, in the step (1), the polymer is 20-25%, the solvent is 70-76%, the plasticizer is 4-5%, and the frame material addition amount is 1-7% of the polymer mass. The addition of the plasticizer makes the membrane have a certain flexibility to meet the use requirements of the oxygenated membrane.

Furthermore, in step (1), the framework material is one or more of a hydrogen-bonded organic framework material, a covalent organic framework material, and a metal-organic framework material; the plasticizer is one or more of tributyl citrate, acetyl tributyl citrate, dioctyl phthalate, diisononyl phthalate, dioctyl adipate, triisooctyl trimellitate, and epoxy soybean oil; the polymer is one or more of polyphenylene ether, polyvinylidene fluoride, polytetrafluoroethylene, polysulfone, polyethersulfone, polypropylene, and poly(4-methyl-1-pentene); and the solvent 1 is one or more of a good solvent for the polymer, including chloroform, benzene, toluene, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

Furthermore, in the step (2), the framework material and the plasticizer are added to the solvent 1, and the polymer is added after the framework material is evenly dispersed after ultrasonic treatment for 1 hour, and the mixture is heated to 80°C and stirred for 8 hours to fully dissolve the polymer and avoid the appearance of small particles. Stirring is stopped, the temperature is lowered to 60°C, and the mixture is allowed to stand for degassing for 6 hours to obtain the casting solution.

Furthermore, in step (3), the solvent 2 is a solvent that is miscible with the solvent 1 and insoluble in the polymer, and is one or more of water, ethanol, and methanol.

Furthermore, in the step (3), the mixed matrix hollow fiber membrane is formed by the NIPS method, the casting solution is added to the spinning machine at a constant temperature of 60°C, and the spinning solution discharged from the annular nozzle is introduced into the solvent 2 coagulation bath.

Furthermore, in the step (3), the distance between the spinneret and the surface of the coagulation bath of solvent 2 is 10 cm-15 cm, and the spinning speed is 2-5 m/min.

Furthermore, in step (3), the outer diameter of the mixed matrix hollow fiber membrane is 300-400 μm, the wall thickness is 50-100 μm, and the cross section presents a porous loose structure.

Beneficial Effects

(1) The present invention prepares a mixed matrix hollow fiber oxygenation membrane by adding a framework material. First, the framework material has the characteristics of a porous structure. After the framework material is introduced, its internal pores will provide additional transmission channels for the transmission of oxygen and carbon dioxide during the oxygenation process. In addition, the triazine groups, carboxyl groups, benzene rings and other groups contained on the surface of the internal pores will produce polar interactions with the carbon dioxide of the electric quadrupole moment, adsorb carbon dioxide to form a high-speed carbon dioxide transmission channel, and greatly improve the gas permeability of the oxygenation membrane. Secondly, the surface of the framework material has organic functional groups, so it has good interface compatibility with organic polymers, avoiding the generation of defects and agglomerations.

(2) The density of the crystalline and amorphous regions of poly(4-methyl-1-pentene) is the same, and the pore size is very small, the crystallization law is different, the crystalline region is irregular, and the grain size and morphology are relatively special, which results in the difficulty in controlling the preparation process of the poly(4-methyl-1-pentene) hollow fiber membrane, which needs to obtain a loose membrane structure to ensure good gas permeability, and the production is very difficult. In contrast, the present invention improves the gas permeability of the oxygenated membrane by preparing a mixed matrix membrane through a simple blending method, and uses the NIPS method for membrane formation, which greatly reduces the difficulty of preparation and avoids complex preparation processes.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 (a) shows the test results of oxygen gas-liquid transmission of hollow fiber oxygenation membrane before and after adding hydrogen bond organic framework PFC-11; Figure 1 (b) shows the comparison of oxygen gas-liquid transmission rate of hollow fiber oxygenation membrane before and after adding hydrogen bond organic framework PFC-11.

Figure 2 is a comparison of the oxygen and carbon dioxide permeation performance of the hollow fiber oxygenation membrane before and after the addition of the hydrogen-bonded organic framework PFC-11.

Detailed ways

Example 1 Preparation of MMM-1 oxygenation membrane

Material formula:

The ratio of polyphenylene ether to toluene is 1:3, tri-n-butyl citrate and hydrogen-bonded organic framework PFC-11 are 24% and 1% of the polymer mass respectively. 20g polyphenylene ether, 60g toluene, 4.8g tri-n-butyl citrate and 200mg hydrogen-bonded organic framework PFC-11 are weighed in proportion.

Preparation of casting solution:

First, weigh toluene, tri-n-butyl citrate and hydrogen-bonded organic framework PFC-11 and add them into a 100 mL three-necked flask, and then ultrasonicate until the hydrogen-bonded organic framework PFC-11 is evenly dispersed to obtain a white suspension. Add polyphenylene ether to the suspension and stir at 80°C for 8 hours. Cool the stirred casting solution to 60°C and let it stand for 6 hours to prepare the hollow fiber membrane.

Preparation of mixed matrix membranes:

The casting solution was added to the spinning machine at a constant temperature of 60°C, and the inner diameter of the annular spinneret was selected to be 250 μm, the outer diameter was 450 μm, and the spinning speed was 2 m/min. The spinning solution spitted out by the annular spinneret was introduced into the ethanol coagulation bath for solvent exchange, and the distance between the spinneret and the surface of the ethanol coagulation bath was 10 cm. The hollow fiber membrane after solvent exchange was soaked in ethanol for 2-3 days to ensure the removal of toluene, and a mixed matrix hollow fiber oxygenation membrane was obtained, named MMM-1.

Example 2 Preparation of MMM-2 oxygenation membrane

Material formula:

The ratio of polyphenylene ether to toluene is 1:3, tri-n-butyl citrate and hydrogen-bonded organic framework PFC-11 are 24% and 2% of the polymer mass respectively. 20g polyphenylene ether, 60g toluene, 4.8g tri-n-butyl citrate and 400mg hydrogen-bonded organic framework PFC-11 are weighed in proportion.

Preparation of casting solution:

First, weigh toluene, tri-n-butyl citrate and hydrogen-bonded organic framework PFC-11 and add them into a 100 mL three-necked flask, and then ultrasonicate until the hydrogen-bonded organic framework PFC-11 is evenly dispersed to obtain a white suspension. Add polyphenylene ether to the suspension and stir at 80°C for 8 hours. Cool the stirred casting solution to 60°C and let it stand for 6 hours to prepare the hollow fiber membrane.

Preparation of mixed matrix membranes:

The casting solution was added to the spinning machine at a constant temperature of 60°C, and the inner diameter of the annular spinneret was selected to be 250 μm, the outer diameter was 450 μm, and the spinning speed was 2 m/min. The spinning solution spitted out by the annular spinneret was introduced into an ethanol coagulation bath for solvent exchange, and the distance between the spinneret and the surface of the ethanol coagulation bath was 10 cm. The hollow fiber membrane after solvent exchange was soaked in ethanol for 2-3 days to ensure the removal of toluene, and a mixed matrix hollow fiber oxygenation membrane was obtained, named MMM-2.

Example 3 Preparation of MMM-3 oxygenated membrane

Material formula:

The ratio of polyphenylene ether to toluene is 1:3, tri-n-butyl citrate and hydrogen-bonded organic framework PFC-11 are 24% and 3% of the polymer mass respectively. 20g polyphenylene ether, 60g toluene, 4.8g tri-n-butyl citrate and 600mg hydrogen-bonded organic framework PFC-11 are weighed in proportion.

Preparation of casting solution:

First, weigh toluene, tri-n-butyl citrate and hydrogen-bonded organic framework PFC-11 and add them into a 100 mL three-necked flask, and then ultrasonicate until the hydrogen-bonded organic framework PFC-11 is evenly dispersed to obtain a white suspension. Add polyphenylene ether to the suspension and stir at 80°C for 8 hours. Cool the stirred casting solution to 60°C and let it stand for 6 hours to prepare the hollow fiber membrane.

Preparation of mixed matrix membranes:

The casting solution was added to the spinning machine at a constant temperature of 60°C, and the inner diameter of the annular spinneret was selected to be 250 μm, the outer diameter was 450 μm, and the spinning speed was 2 m/min. The spinning solution spitted out by the annular spinneret was introduced into the ethanol coagulation bath for solvent exchange, and the distance between the spinneret and the surface of the ethanol coagulation bath was 10 cm. The hollow fiber membrane after solvent exchange was soaked in ethanol for 2-3 days to ensure the removal of toluene, and a mixed matrix hollow fiber oxygenation membrane was obtained, named MMM-3.

Comparative Example 1 Preparation of MMM-0 oxygenation membrane

Material formula:

The ratio of polyphenylene ether to toluene is 1:3, and tri-n-butyl citrate accounts for 24% of the polymer mass. 20 g of polyphenylene ether, 60 g of toluene, and 4.8 g of tri-n-butyl citrate are weighed in proportion.

Preparation of casting solution:

First, weigh toluene, tri-n-butyl citrate and polyphenylene ether into a 100 mL three-necked flask and stir at 80°C for 8 hours. The stirred casting solution is cooled to 60°C and allowed to stand for 6 hours to prepare the hollow fiber membrane.

Preparation of mixed matrix membranes:

The casting solution was added to the spinning machine at a constant temperature of 60°C, and the inner diameter of the annular spinneret was selected to be 250μm, the outer diameter was 450μm, and the spinning speed was 2m/min. The spinning solution spitted out by the annular spinneret was introduced into the ethanol coagulation bath for solvent exchange, and the distance between the spinneret and the surface of the ethanol coagulation bath was 10cm. The hollow fiber membrane after solvent exchange was soaked in ethanol for 2-3 days to ensure the removal of toluene, and a hollow fiber oxygenation membrane was obtained, which was named MMM-0.

Test Example 1 Test on oxygen gas-liquid transmission performance of mixed matrix membrane hollow fiber oxygenation membrane

The oxygen gas-liquid transmission performance of MMM-0, MMM-1, MMM-2, and MMM-3 was tested using deionized water to simulate blood. Refer to Figure 1(a). The broken line in the figure reflects the speed at which the simulated liquid reaches oxygen saturation. The oxygen transmission of the mixed matrix membrane with the addition of hydrogen-bonded organic framework PFC-11 is significantly better than that of the pure polyphenylene ether hollow fiber membrane without the addition, among which MMM-3 has the best effect. Refer to Figure 1(b). The oxygen gas-liquid transmission capacity of MMM-0 without the addition of hydrogen-bonded organic framework PFC-11 is only 22.4 mL/(min·m ² ), while the oxygen gas-liquid transmission capacity of MMM-3 is increased to 35.2 mL/(min·m ² ), an increase of 57.1%.

Test Example 2 Gas Permeability Test of Mixed Matrix Membrane Hollow Fiber Oxygenation Membrane

The oxygen and carbon dioxide gas permeability of MMM-0, MMM-1, MMM-2, and MMM-3 was tested. See Figure 2. It can be seen from Figure 2 that the addition of the hydrogen bond organic framework PFC-11 effectively improves the oxygen and carbon dioxide permeability. For MMM-3, it increased from 1.62 GPU of MMM-0 to 3.51 GPU, an increase of 116.5%.

The above are only preferred embodiments of the present invention and are not limitations of the present invention. Any technician in the field may use the technical content disclosed above to make changes or improvements. However, any modifications, equivalent changes and improvements made to the above embodiments based on the technical essence of the present invention without departing from the concept of the present invention are still within the protection scope of the present invention.

Claims (4)

1. A mixed matrix hollow fiber oxygenation membrane based on a frame material, characterized in that the preparation method comprises the following steps: (1) Weighing materials according to a formula, wherein the weight percentages in the material formula are: polymer: 20-25%, solvent 1: 70-76%, plasticizer: 4-5%, and the amount of frame material added is 1-7% of the weight of the polymer, and the weight percentages of the above components total 100%; the plasticizer is one or more of tributyl citrate, acetylcitrate tributyl, dioctyl phthalate, dioctyl adipate, and epoxy soybean oil; the polymer is one or more of polyphenylene ether, polyvinylidene fluoride, polytetrafluoroethylene, polysulfone, polyethersulfone, polypropylene, and poly(4-methyl-1-pentene); (2) First add part of the materials, add the framework material and plasticizer into solvent 1, perform ultrasonic treatment until the framework material is evenly dispersed, then add the polymer, heat to 80° C. and stir for 8 h, then cool to 60° C. and stand for degassing for 6 h to obtain a casting solution; (3) Selecting a suitable spinneret for spinning, adding the casting solution to the spinning machine at a constant temperature of 60°C, introducing the spinning solution discharged from the annular nozzle into the coagulation bath of solvent 2, and forming a mixed matrix hollow fiber oxygenated membrane by the NIPS method; Solvent 1 is one or more of the good solvents for the polymer, including chloroform, benzene, toluene, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; Solvent 2 is one or more of the solvents that are miscible with solvent 1 and insoluble in the polymer, including water, ethanol, and methanol. 2. A mixed matrix hollow fiber oxygenation membrane based on a framework material according to claim 1, characterized in that: In the step (1), the framework material is one or more of a hydrogen-bonded organic framework material, a covalent organic framework material or a metal-organic framework material. 3. A mixed matrix hollow fiber oxygenation membrane based on a frame material according to claim 1, characterized in that: In the step (3), the outer diameter of the mixed matrix hollow fiber oxygenation membrane is 300-400 μm, the wall thickness is 50-100 μm, and the cross section presents a porous loose structure. 4. Use of a mixed matrix hollow fiber oxygenation membrane based on a framework material according to any one of claims 1 to 3 in the field of extracorporeal membrane oxygenation.