CN114870655A

CN114870655A - Preparation method and application of mixed matrix membrane for realizing efficient gas separation through in-situ crosslinking

Info

Publication number: CN114870655A
Application number: CN202210505706.8A
Authority: CN
Inventors: 杨延琴; 岳俊博; 李怡璇; 韩禄; 孙树政
Original assignee: Hebei University of Technology
Current assignee: Hebei University of Technology
Priority date: 2022-05-10
Filing date: 2022-05-10
Publication date: 2022-08-09
Anticipated expiration: 2042-05-10
Also published as: CN114870655B

Abstract

The invention relates to a preparation method and application of a mixed matrix membrane for realizing efficient gas separation through in-situ crosslinking. Adding a polymer matrix mixed solution into a 3D-TB mixed solution reaction system, and carrying out in-situ crosslinking reaction to obtain a 3D-TB @ TB product mixed solution; purifying to obtain a polymer material; coating the solution on a glass plate after dissolution to obtain a film; the mixed matrix membrane is used for separating mixed gas (such as CO) ₂ /CH ₄ Mixed gas, CO ₂ /N ₂ Mixed gas, etc.) to separate and capture CO ₂ . Compared with the original TB pure film or the simple 3D-TB/TB physical blending film, the gas separation performance and the mechanical property of the 3D-TB @ TB in-situ crosslinking mixed matrix filmThe performance is more excellent.

Description

Preparation method and application of mixed matrix membrane for realizing efficient gas separation through in-situ crosslinking

Technical Field

The invention relates to the technical field of functional materials and polymer separation membranes, relates to a porous polymer material with a large specific surface area, a gas separation membrane and a preparation method thereof, and particularly relates to a porous polymer material and a preparation method thereof, and a technology for preparing a mixed matrix membrane by in-situ crosslinking and a solution casting method.

Background

The socio-economic development requires the consumption of a large amount of fossil energy, and environmental pollution and greenhouse effect caused by the consumption are currently important global problems. CO 2 ₂ Is an important greenhouse gas, and how to effectively separate and capture CO ₂ Become a focus of attention of researchers in various countries.

Common CO ₂ The separation and collection method includes an absorption method, an adsorption method, a low-temperature treatment method, and a membrane separation method. Among them, the membrane separation technology has the advantages of stability, high separation efficiency, low energy consumption, environmental friendliness and the like, has attracted greater attention and development in recent years, and is widely applied to the aspects of pervaporation, gas separation and the like. The separation membrane used in the gas separation technology can be classified into an inorganic membrane, an organic membrane, and a mixed matrix membrane, depending on the type of the membrane material. Organic polymer membranes are widely used in industry due to their good processability, and common organic polymer membrane materials include Polyimide (PI), self-polymerized microporous Polymer (PIM), polyethylene oxide (PEO), and the like, but these materials are difficult to overcome the mutual restriction between permeability and selectivity (trade-off effect), and the membrane performance is usually limited below the upper bound of Robeson; inorganic membranes have been the hot spot of membrane technology research with excellent separation performance, thermal stability and chemical stability, but the further development of inorganic membranes is hindered by high cost and difficult scale preparation. To address these problems, researchers have attempted to combine the advantages of low cost, easy film formation of organic polymer films with the advantages of high performance of inorganic films, the most common strategy being the preparation of Mixed Matrix Membranes (MMMs).

The mixed matrix membrane is formed by adding inorganic or organic materials into polymer to improve the permeability and selectivity of the membrane. In recent years, various materials such as inorganic oxides, carbon materials, zeolites, and the like, and microporous molecular sieve materials such as newly developed metal-organic frameworks (MOFs), Covalent Organic Frameworks (COFs), Microporous Organic Polymers (MOPs), and the like have been used to prepare mixed matrix membranes. The mixed matrix membrane has improved permeability with the addition of the microporous solid filler, but is accompanied by a decrease in selectivity; methods such as filler engineering (small molecule surface modification and polydopamine modification formation) and polymer modification (functional group introduction) have been proposed to improve the selectivity of mixed matrix membranes, but generally accompanied by a different degree of permeability reduction; in addition, interfacial defects between the organic polymer matrix and the solid filler particles can also affect the performance of the mixed matrix membrane. To address this problem, researchers have proposed methods of in situ crosslinking of polymers and fillers to make mixed matrix membranes.

Disclosure of Invention

The invention aims to provide a preparation method and application of a mixed matrix membrane for realizing efficient gas separation by in-situ crosslinking aiming at the defects in the prior art. The method realizes the preparation and chemical crosslinking of the filler and the matrix in the same polymerization system; wherein the rigidity is selected

As a polymer matrix, of

The filler is used as a porous polymer filler; theoretically, after two reaction media are mixed, 3D-TB with unreacted amino on the surface can be subjected to in-situ crosslinking with a growing TB chain to complete grafting, and the 3D-TB @ TB polymer obtained after polymerization is used for preparing MMMs. Compared with an original TB pure film or a simple 3D-TB/TB physical blending film, the 3D-TB @ TB in-situ crosslinking mixed matrix film has more excellent gas separation performance and mechanical performance.

The technical scheme of the invention is as follows:

a preparation method of a mixed matrix membrane for realizing high-efficiency gas separation by in-situ crosslinking comprises the following steps:

(1) preparing a filler raw material mixed solution A: adding an aromatic polyamine compound into Dimethoxymethane (DMM) under the conditions of protective gas atmosphere and ice water bath, and stirring to obtain a raw material mixed solution A;

wherein, every 1g of aromatic polyamine compound is added with 5-8 mL of DMM;

the aromatic polyamine compound is as follows:

wherein, (a) is tetra (4-aminophenyl) methane, (b) is tetra (4-aminophenyl) adamantane, (c) is diamido triptycene, (d) is triamido triptycene, and (e) is triamino triphenylmethane;

(2) preparation of the Polymer Filler 3D-TB: under the conditions of protective gas atmosphere and ice-water bath, adding trifluoroacetic acid (TFA) into the raw material mixed solution A obtained in the step (1), removing the ice-water bath after adding the TFA, and stirring and reacting for 12-24 h at room temperature to obtain a 3D-TB mixed solution;

wherein, 30-80 mL TFA is added into each 1g of aromatic polyamine compound;

(3) preparation of polymer matrix feedstock liquid B: uniformly dispersing aromatic diamine in Dimethoxymethane (DMM) under the conditions of protective gas atmosphere and ice-water bath to obtain a raw material mixed solution B;

wherein, every 1g of aromatic diamine compound is added with 5-8 mL of DMM;

the aromatic diamine compound monomer is as follows:

(o-tolidine) or

One of (1, 5-naphthalenediamine);

(4) preparation of polymer matrix mixture: under the conditions of protective gas atmosphere and ice-water bath, adding a trifluoroacetic acid (TFA) solvent into the raw material mixed solution B obtained in the step (3), and magnetically stirring to dissolve an aromatic diamine monomer to obtain a polymer matrix mixed solution;

wherein, 15-30 mL TFA is added into each 1g of aromatic diamine compound;

(5) in situ crosslinking of the polymer matrix with the filler: adding the polymer matrix mixed solution obtained in the step (4) into the 3D-TB mixed solution reaction system obtained in the step (2) under the conditions of protective gas atmosphere and ice-water bath, removing the ice-water bath after the matrix mixed solution is added, magnetically stirring and reacting for 72-96 h at room temperature, and further carrying out in-situ crosslinking reaction to obtain a 3D-TB @ TB product mixed solution;

wherein in the reaction system, the mass ratio of the polyamine compound monomer to the diamine compound monomer is 1: 1-50;

(6) post-treatment of the cross-linking product mixture: immersing the mixed solution of the 3D-TB @ TB product obtained in the step (5) in dilute ammonia water, filtering, washing the product 3D-TB @ TB with excessive deionized water until the pH value is neutral, and drying at the temperature of 60-80 ℃ in vacuum to obtain a product;

wherein the volume of the dilute ammonia water is 3-5 times of that of trifluoroacetic acid in a reaction system, and the concentration of the dilute ammonia water is 10-20%;

(7) and (3) purifying a product: dispersing and dissolving the 3D-TB @ TB product obtained in the step (6) in chloroform (CHCl) ₃ ) Obtaining a viscous solution, magnetically stirring for 24-30 h at room temperature, then precipitating in anhydrous methanol to obtain a filamentous product 3D-TB @ TB, washing for 2-3 times by using the anhydrous methanol, and drying at the temperature of 60-80 ℃ in vacuum to obtain a polymer material;

the structural formula is

Wherein, 5-10 mL of CHCl is added into every 1g of 3D-TB @ TB polymer ₃ ；

(8) Preparation of the film: adding the dried polymer material into trichloromethane for ultrasonic dispersion, and magnetically stirring for 24-30 hours at room temperature to obtain a viscous solution; then coating the viscous solution on a glass plate in a trichloromethane steam atmosphere, and drying at room temperature for 12-36 hours to obtain a film;

wherein the thickness of the film is 5-200 μm;

wherein, 5-10 mL of CHCl is added into every 1g of polymer material ₃ ；

(9) Activation of the membrane: soaking the obtained film in absolute methanol for 12-24 h, and then drying in a vacuum oven at 90-180 ℃ for 12-24 h to obtain the in-situ crosslinking mixed matrix film;

wherein the protective gas is argon or nitrogen, and the optimal protective gas is argon;

wherein, the purity of the trifluoroacetic acid is 99.5 percent;

the application of the mixed matrix membrane for realizing high-efficiency gas separation by in-situ crosslinking is used for separating CO ₂ . Preferably, CO is separated and captured from the mixed gas ₂ (ii) a The mixed gas is CO ₂ /CH ₄ Mixed gas, CO ₂ /N ₂ And (4) mixing the gases.

A polymer material obtained by in-situ crosslinking, wherein the structural formula of the material is as follows:

wherein Ar is ₁ Is an aromatic polyamine compound, Ar ₂ Is an aromatic diamine compound, and is characterized in that,

is a repeating unit structure

Ar is ₁ The structural formula of (A) is:

one of them; wherein, (a) is tetra (4-aminophenyl) methane, (b) is tetra (4-aminophenyl) adamantane, (c) is diamido triptycene, (d) is triamido triptycene, and (e) is triamino triphenylmethane;

ar is ₂ The method specifically comprises the following steps:

(o-tolidine) or

(1, 5-naphthalenediamine).

Compared with the prior art, the invention has the substantial characteristics that:

in the current art, conventional mixed matrix membranes polymer matrices and fillers are prepared separately and then the membrane is obtained by "physical blending"; in this way, since the physically mixed film is composed of the insoluble filler and the soluble polymer matrix, poor interfacial compatibility between the two and interfacial voids are inevitable, resulting in poor gas separation performance.

The invention obtains mixed matrix membrane material in the same reaction system (the core as filler and the polymer as matrix are prepared in the same reaction system); because unreacted amino exists on the surface of the core 3D-TB as the filler, the reaction solution for preparing the 3D-TB can be introduced into a diamine monomer reaction system, and the amino of the diamine monomer can perform in-situ crosslinking polymerization reaction with the unreacted amino on the 3D-TB, which is equivalent to grafting a chain consisting of diamine on the surface of the core 3D-TB (the material obtained by self-polymerization of the diamine monomer can form a film); by controlling the ratio of this core (filler) to chain (polymer), different ratios of "in situ cross-linked mixed matrix membrane" materials (10 wt%, 5 wt%, 20 wt% in examples 1, 2, 3) can be obtained. The material obtained by the invention can be directly used for obtaining a membrane by a solution casting method, and the in-situ cross-linked mixed matrix membrane obtained by the method has smaller defects and better compatibility between two phases compared with the mixed matrix membrane obtained by physical mixing (as can be seen from an SEM image in an example).

The invention has the beneficial effects that:

(1) the invention provides a porous polymer material and a preparation method thereof, and a method for preparing a mixed matrix membrane by simultaneously carrying out in-situ crosslinking and then by a solution casting method, wherein the reaction condition is mild, and the synthesis and preparation are simple;

(2) compared with an original TB pure film or a simple 3D-TB/TB physical blending film, the in-situ crosslinking mixed matrix film provided by the invention has more excellent performance of the 3D-TB @ TB in-situ crosslinking mixed matrix film, and CO ₂ Compared with pure TB film, the permeability can be improved by 61 percent at most, and CO is ₂ /N ₂ The selectivity is improved by 28 percent.

(3) The preparation method of the in-situ cross-linking mixed matrix membrane provided by the invention effectively enhances the dispersibility of the material in the polymer matrix and the compatibility of two-phase interfaces, thereby reducing the interface defects and having good research and development prospects in the aspect of gas separation membranes.

Drawings

FIG. 1 is an infrared spectrum (IR) of the monomer, the porous organic polymer 3D-TB and the polymer TB of example 1;

FIG. 2 is X-ray photoelectron spectroscopy (XPS) of the porous organic polymer 3D-TB of example 1;

FIG. 3 is a Scanning Electron Micrograph (SEM) of the porous organic polymer 3D-TB of example 1;

FIG. 4 is a nitrogen adsorption-desorption isotherm (77K) of the porous organic polymer 3D-TB of example 1;

FIG. 5 is a thermogravimetric analysis (TGA) of the porous organic polymer 3D-TB of example 1;

FIG. 6 is a cross-sectional Scanning Electron Micrograph (SEM) of the resulting film of examples 1, 2, 3, 4 wherein FIG. 6(a) is a 5 wt% 3D-TB @ TB film, FIG. 6(b) is a 10 wt% 3D-TB @ TB film, FIG. 6(c) is a 20 wt% 3D-TB @ TB film, and FIG. 6(D) is a 10 wt% 3D-TB/TB film;

FIG. 7 is a bar graph of the gas separation performance of the resulting membranes in examples 1, 2, 3, 4;

FIG. 8 is a graph of the mechanical properties of the resulting films of examples 1, 2, 3, 4;

Detailed Description

The invention is prepared by the same polymerization system

Polymers and

fillers, which enable in-situ crosslinking reaction to occur between the fillers to prepare the MMM with better interface compatibility; among them, the tygon-type polymers (TBs) having a V-bridge type bicyclic structure can be prepared from aromatic diamines, represent a group of high performance Polymers (PIMs) having intrinsic micropores, and are widely considered as promising gas separation membrane materials; researches show that when aromatic diamine is changed into polyamine, a three-dimensional Tegeline type bridge porous network (3D-TBs) material can be prepared, and the material can obtain good CO by a physical mixing method ₂ /N ₂ Separating the performance MMMs. In this study, rigidity

As a polymer matrix, of

The filler is used as a porous polymer filler; theoretically, after mixing the two reaction media, the 3D-TB with unreacted amino groups on the surface can be combined with the slowly formed TB chain, and the 3D-TB @ TB mixture obtained after polymerization is used for preparing MMMs. Our hypothesis is that in-situ crosslinking can enhance the compatibility between the TB matrix and the 3D-TB filler, minimizing the formation of interfacial defects. For comparison, a simple physical mixing and casting method was used to prepare MMMs by physically mixing the TB matrix with the 3D-TB filler, followed by CO ₂ /N ₂ MMMs prepared by evaluating binary mixed gas in CO ₂ Potential applications in capture and separation, it was found that the problem of poor two-phase compatibility between conventional membrane fillers and polymer matrices is effectively solved by an in situ cross-linking process.

The invention is further illustrated below by means of specific experimental procedures. The following examples are intended to illustrate the invention without further limitation of the invention.

Example 1

A method for preparing a porous polymer material and preparing a mixed matrix membrane by simultaneously carrying out in-situ crosslinking and then carrying out solution casting comprises the following steps:

(1) preparing a filler raw material mixed solution: under the conditions of argon protective gas atmosphere and ice-water bath, adding 0.1g (0.263mmol) of tetrakis (4-aminophenyl) methane (TAPM) as a monomer into a dry 50mL three-neck flask, then adding 0.5mL of Dimethoxymethane (DMM), and stirring for 0.5h by using magnetic force to obtain a raw material mixed solution;

(2) preparation of porous organic Polymer Filler 3D-TB: adding 7mL of trifluoroacetic acid (TFA) into the mixed solution obtained in the step (1) under the conditions of argon protective gas atmosphere and ice-water bath, removing the ice-water bath after the TFA is completely added, stirring the reaction system at room temperature for reacting for 24 hours, and further reacting to obtain 3D-TB mixed solution;

wherein, in order to obtain the characterization data of the 3D-TB material, the reaction is processed as follows:

and (3) performing characterization: the mixed solution in the step (2) is precipitated in 50mL of dilute ammonia water (the concentration is 10%), the precipitated 3D-TB solid is washed to be neutral by water, and is washed for 3 times by using dichloromethane, acetone and methanol in sequence, and the solid powder 3D-TB is obtained by drying at the temperature of 60 ℃ in vacuum; the structure of the compound is shown as the following formula:

the FT-IR of the 3D-TB powder was analyzed, and it was 1322cm in length as shown in FIG. 1 ^-1 And 1023cm ^-1 The absorption band between the two represents the C-N peak in the Teller-Gebase, which proves the formation of the bridge structure; furthermore, the infrared relative to the monomeric TAPM, after 3D-TB formation, was at 3400cm ^-1 To 3200cm ^-1 The strength of the left and right characteristic bands corresponding to the aromatic amine tensile band is obviously reduced and does not disappear, which indicates that unreacted amino exists on the surface of the 3D-TB polymer; is composed ofIt is further proved that the 3D-TB powder is subjected to XPS analysis, as shown in FIG. 2, after the 3D-TB material is synthesized, N-H bond energy still exists, and the existence of some unreacted terminal amino groups is fully proved; two characterization results illustrate the successful synthesis of the porous organic polymer material 3D-TB and the presence of unreacted terminal amino groups on the surface of the material;

in addition, SEM analysis is carried out on the 3D-TB material, as shown in figure 3, the particle size of the 3D-TB material is about 90-100 nm; by N at 77K ₂ The adsorption-desorption isotherm analysis of the specific surface area of 3D-TB (FIG. 4), specifically, 3D-TB has a large specific surface area of 529m ² g ^-1 (ii) a The TGA results show that 3D-TB remains stable up to 400 ℃ (FIG. 5), with good thermal stability;

(3) preparation of polymer matrix stock solution: under the conditions of argon protective gas atmosphere and ice-water bath, 0.9g (4.24mmol) of o-tolidine (OT) is taken as a monomer, added into a dry 50mL three-neck flask, then added with 4.5mL of Dimethoxymethane (DMM), and stirred for 0.5h by magnetic force to obtain a mixed solution;

(4) preparation of TB Polymer matrix mixture: adding 16mL of TFA into the raw material mixed solution obtained in the step (3) under the conditions of argon protective gas atmosphere and ice-water bath, and promoting the dissolution of OT monomers by magnetic stirring to obtain a mixed solution;

to obtain characterization data for TB polymers, the above reactions were subjected to different treatments:

(a) and (3) performing characterization: magnetically stirring the mixed solution in the step (4) for 96 hours at room temperature under the atmosphere of protective gas, slowly precipitating the mixed solution of the reaction product in 50mL of dilute ammonia water (the concentration is 10%), washing the product TB to be neutral by water, washing the product TB for 3 times by using anhydrous methanol, and drying the product TB at the temperature of 80 ℃ in vacuum to obtain a TB polymer; purification was carried out by the method of step (7) in example 1, and storage under dry conditions was carried out; the structure of TB is schematically shown as follows:

analysis of TB Polymer and FT-IR is shown in FIG. 1At 1322cm ^-1 And 1023cm ^-1 The absorption band between the two represents the C-N peak in the Teller-Guerin, which proves the formation of the bridge structure and explains the successful synthesis of the TB polymer material;

(b) and (3) continuing the reaction: continuously keeping the mixed solution in the step (4) in a solution state to prepare for the in-situ crosslinking in the step (5);

(5) in-situ cross-linking polymerization of polymer matrix with filler: adding the mixed solution obtained in the step (4) into the system reacted for 24 hours in the step (2) under the conditions of argon protective gas atmosphere and ice-water bath, removing the ice-water bath after the mixed solution is completely added, magnetically stirring at room temperature for reaction for 96 hours, and further carrying out in-situ crosslinking reaction to obtain a 3D-TB @ TB product mixed solution;

wherein in the reaction system, the mass ratio of the TAPM monomer to the OT monomer is 1: 9;

(6) post-treatment of the cross-linking product mixture: precipitating the product mixed solution obtained in the step (5) in 75mL of dilute ammonia water (the concentration is 10%), washing the product to be neutral, washing the product for 3 times by using anhydrous methanol, and drying the product at the temperature of 80 ℃ in vacuum to obtain 10 wt% of 3D-TB @ TB;

wherein, 10 wt% is the percentage of the weight of TAPM monomer in the total weight of TAPM and OT;

(7) purification of the crosslinked product: 1g of the dried product of step (6), 10 wt% _3D-TB @ TB, was weighed out and dispersed in 5mL of chloroform (CHCl) ₃ ) Obtaining a viscous solution, stirring at room temperature for 48h, then precipitating the viscous solution in anhydrous methanol to obtain a filamentous product 10 wt% 3D-TB @ TB, filtering, continuously washing for 2 times by using the anhydrous methanol, and drying at the temperature of 80 ℃ in vacuum to obtain a product;

since the TB chain is crosslinked (grafted) in situ onto 3D-TB while polymerization continues to occur, it can be deduced that the structure of its crosslinked product is schematically shown as follows:

(8) preparation of the film: 0.5g of dried 10 wt% of 3D-TB @ TB polymer monomer was weighed out and dissolved in 2.5mL of CHCl ₃ Magnetically stirring for 24 hours at room temperature to obtain a viscous solution, then, in a closed environment filled with chloroform steam, performing scratch coating on the viscous solution on a glass plate by using a scraper with the thickness of 500 mu m and the width of 10cm, and drying for 12 hours at room temperature to obtain an in-situ crosslinked mixed matrix film of 10 wt% 3D-TB @ TB;

(9) activation of the membrane: soaking the obtained membrane in anhydrous methanol for 12h to remove residual solvent, and drying in a vacuum oven at 120 deg.C for 12h to obtain membrane for gas separation test;

example 2

The other steps were the same as example 1 except that the mass of TAPM in step (1) was changed from 0.1g to 0.05g, the volume of DMM was changed from 0.5mL to 0.25mL, the volume of TFA in step (2) was changed from 7mL to 3.5mL, the mass of OT in step (3) was changed from 0.9g to 0.95g, and the volume of DMM was changed from 4.5mL to 4.75 mL;

finally obtaining an in-situ crosslinked mixed matrix membrane 5 wt% _3D-TB @ TB membrane, and carrying out gas separation test on the obtained membrane;

wherein, 5 wt% is the percentage of the monomer TAPM in the total mass of TAPM + OT;

example 3

The other steps were the same as example 1 except that the mass of TAPM in step (1) was changed from 0.1g to 0.2g, the volume of DMM was changed from 0.5mL to 1mL, the volume of TFA in step (2) was changed from 7mL to 14mL, the OT mass in step (3) was changed from 0.9g to 0.8g, and the volume of DMM was changed from 4.5mL to 4 mL;

finally obtaining an in-situ crosslinked mixed matrix membrane 20 wt% -3D-TB @ TB membrane, and carrying out gas separation test on the obtained membrane;

wherein, 20 wt% is the percentage of the monomer TAPM in the total mass of TAPM + OT;

example 4

To compare the properties of the in situ crosslinked membranes obtained in the above examples, pure TB membranes were prepared as well as 10 wt% 3D-TB/TB mixed matrix membranes obtained by "physical blending";

wherein the film preparation procedure for pure TB was the same as in example 1, step (8) and step (9), except that the polymer in step (8) was changed from 10 wt% to 3D-TB @ TB to the TB polymer obtained in example 1, step (4 a);

a10 wt% 3D-TB/TB mixed matrix film was prepared by the conventional "physical blending of polymer matrix with filler" process comprising the steps of:

0.05g of the 3D-TB filler obtained during the characterization in step (2) of example 1 was weighed out and dispersed in 2.5mL of CHCl ₃ After stirring the mixture ultrasonically and magnetically for 24 hours in a solvent, 0.45g of the TB polymer matrix obtained in the step (a) in the step (4) was added to the system, and stirring was continued for 24 hours to obtain a viscous solution, and then a 10 wt% 3D-TB/TB mixed matrix membrane was obtained according to the preparation methods of the step (8) and the step (9) in example 1;

among them, the pure TB membrane of example 4 and 10 wt% _3D-TB/TB mixed matrix membrane were prepared for comparative testing to demonstrate the excellent performance of the in situ cross-linked mixed matrix membrane;

SEM analysis of the cross section of the film formed (FIG. 6) all x-3D-TB @ TB films had a dense and integrated morphology. In particular for 10 wt% -3D-TB @ TB (FIG. 6b), the filler was uniformly coated by the polymer matrix, which means that the in situ crosslinking grafting reaction significantly enhanced the matrix-filler interface; for the 10 wt% _3D-TB/TB physically blended film (FIG. 6D), although there was no significant polymer wrapping at the interface, it also exhibited excellent filler/polymer adhesion, which we attributed to the Tegler base functionalized backbone possessed by the 3D-TB filler and the TB matrix, facilitating good interfacial adhesion and compatibility between the polymer matrix and the filler.

The gas properties of the resulting film are shown in FIG. 7, although the CO of x-3D-TB @ TB ₂ Permeability increases with filler loading, but in CO ₂ /N ₂ The volcanic profile was clearly observed selectively and was significantly dependent on 3D-TB loading; in addition, the tests found that the selectivity of the 20 wt% _3D-TB @ TB film decreased, which may be due to under-filling of the polymer chains and aggregation of the filler at 20 wt% filler loading, resulting in some non-selective voids in the film; thus, a 10 wt% 3D-TB @ TB membrane has the best gas separation performance, with CO ₂ The permeability (90.75Barrer) is improved by 61 percent compared with that of a pure TB film (54Barrer), and the CO content is increased by 61 percent ₂ /N ₂ SelectingThe performance (35.75) was improved by 28% compared to pure TB film (27.8). (wherein the volume ratio of CO is 1: 4 ₂ /N ₂ The mixed gas was used as a test gas, and a gas separation test was conducted using a Labthink permeation system (G2-110) at a feed temperature of 20 ℃ and a feed pressure of 1 bar. )

In addition, to further illustrate the advantages of the in situ cross-linked mixed matrix membranes, analytical tests were performed on mechanical properties of pure TB membranes, in situ cross-linked mixed matrix membranes, and physically mixed matrix membranes; as shown in FIG. 8, it was found that the mechanical properties of the x-3D-TB @ TB film gradually decreased with increasing 3D-TB loading; wherein, the mechanical property of 5 wt% 3D-TB @ TB film (the stretching force is 76.4MPa) is better than that of pure TB film (the stretching force is 60.3MPa), and in addition, the mechanical property of 10 wt% 3D-TB @ TB film (the stretching force is 55.1MPa) is better than that of 10 wt% 3D-TB/TB film (the stretching force is 53.2MPa) prepared by physical mixing in the conventional way, which can be proved by the strain at the breaking point; these data indicate that the combination of 3D-TB filler and TB matrix by in situ cross-linking contributes to better, more effective two-phase interfacial compatibility than traditional MMM. (tensile measurements were made using a microcomputer controlled electronic Universal tester (CMT6104) at a speed of 5 mm/min under ambient conditions (50% relative humidity))

As can be seen from the above examples, the present invention is based on

base Polymer (TB) and 3D

A new generation of mixed matrix membranes for base fillers (3D-TB) prepared by in-situ cross-linking polymerization, wherein TB chains are in-situ cross-linked (grafted) onto the 3D-TB fillers; it can be observed from the SEM images that the in-situ cross-linked mixed matrix membrane exhibits a dense morphology in which the 3D-TB filler is uniformly wrapped by the polymer matrix, a phenomenon that cannot be observed in the membrane prepared by the conventional physical mixing method. The in situ cross-linking polymerization process of the present invention has three main advantages: (1) the 3D-TB can directly participate in the polymerization reaction of the TB without any separation, purification or redispersionThe whole material preparation process is easy to amplify by treatment; (2) the grafting reaction and polymerization process of TB occur simultaneously, providing molecular level homogeneity for MMMs; (3) grafting occurs at the early polymerization stage, the TB porosity is closely connected with the internal 3D-TB pores, and an interconnected micropore network is formed in the whole MMM, and the interconnected micropore design not only effectively eliminates the voids of the polymer and filler interface, but also promotes gas transportation in the MMM; the results reported in the present invention will provide useful guidance for future development of TB-based MMM and other porous organic networks.

The invention is not the best known technology.

Claims

1. A method for preparing a mixed matrix membrane for realizing high-efficiency gas separation by in-situ crosslinking is characterized by comprising the following steps:

(1) preparing a filler raw material mixed solution A: adding an aromatic polyamine compound into Dimethoxymethane (DMM) under the conditions of protective gas atmosphere and ice-water bath, and stirring to obtain a raw material mixed solution A;

wherein, every 1g of aromatic polyamine compound is added with 5-8 mL of DMM;

the aromatic polyamine compound is as follows:

(a)

(b)

(c)

(d)

or (e)

wherein, 30-80 mL TFA is added into each 1g of aromatic polyamine compound;

wherein, every 1g of aromatic diamine compound is added with 5-8 mL of DMM;

the aromatic diamine compound monomer is as follows:

(o-tolidine) or

One of (1, 5-naphthalenediamine);

wherein, 15-30 mL TFA is added into each 1g of aromatic diamine compound;

(5) in situ crosslinking of the polymer matrix with the filler: adding the polymer matrix mixed solution obtained in the step (4) into the 3D-TB mixed solution reaction system obtained in the step (2) under the conditions of protective gas atmosphere and ice-water bath, removing the ice-water bath after the addition of the matrix mixed solution is finished, magnetically stirring at room temperature for reaction for 72-96 hours, and further carrying out in-situ crosslinking reaction to obtain a 3D-TB @ TB product mixed solution;

(6) post-treatment of the cross-linking product mixture: immersing the mixed liquid of the 3D-TB @ TB product obtained in the step (5) in dilute ammonia water, filtering, washing the product 3D-TB @ TB with excessive deionized water until the pH value is neutral, and drying at the temperature of 60-80 ℃ in vacuum to obtain a product;

wherein the concentration of the dilute ammonia water is 10-20%;

the structural formula is

Wherein, 5-10 mL of CHCl is added into every 1g of 3D-TB @ TB polymer ₃ ；

(8) Preparation of the film: adding the dried polymer material into trichloromethane for ultrasonic dispersion, and magnetically stirring for 24-30 hours at room temperature to obtain a viscous solution; then coating the viscous solution on a glass plate in a trichloromethane steam atmosphere, and drying at room temperature for 12-36 h to obtain a film;

wherein the thickness of the film is 5-200 μm; adding 5-10 mL of CHCl into every 1g of polymer material ₃ ；

(9) Activation of the membrane: and soaking the obtained film in absolute methanol for 12-24 h, and then drying in a vacuum oven at 90-180 ℃ for 12-24 h to obtain the in-situ crosslinking mixed matrix film.

2. The method for preparing the mixed matrix membrane for realizing efficient gas separation by in-situ crosslinking according to claim 1, wherein in the step (6), the volume of the dilute ammonia water is 3-5 times of that of the trifluoroacetic acid in the reaction system.

3. The method for preparing a mixed matrix membrane for achieving high efficiency gas separation through in-situ crosslinking according to claim 1, wherein the shielding gas in steps (1) to (5) is argon or nitrogen.

4. Use of a mixed matrix membrane for efficient separation of gases by in situ cross-linking, prepared according to the process of claim 1, characterized by the fact that it is used for separation of CO ₂ 。

5. Use of the mixed matrix membrane for efficient gas separation by in-situ crosslinking, prepared according to the method of claim 4, wherein CO is separated and captured from the mixed gas ₂ (ii) a The mixed gas is CO ₂ /CH ₄ Mixed gas or CO ₂ /N ₂ And (4) mixing the gases.

6. A polymer material obtained by in-situ crosslinking is characterized in that the material has a structural formula as follows: