CN114870655B

CN114870655B - Preparation method and application of mixed matrix membrane for realizing efficient gas separation through in-situ crosslinking

Info

Publication number: CN114870655B
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: 2023-05-12
Anticipated expiration: 2042-05-10
Also published as: CN114870655A

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 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 dissolved film on a glass plate to obtain a film; the mixed matrix membrane is used for producing a gas mixture (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 a simple 3D-TB/TB physical blend film, the 3D-TB@TB in-situ crosslinking mixed matrix film has more excellent gas separation performance and mechanical performance.

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 the technical field of polymer separation membranes, and relates to a porous polymer material with larger specific surface area, a gas separation membrane and a preparation method thereof, in particular to a porous polymer material and a preparation method thereof, and simultaneously, in-situ crosslinking is carried out, so as to prepare a mixed matrix membrane by a solution casting method.

Background

The social and economic development requires a large amount of fossil energy, and the environmental pollution and the greenhouse effect caused by the consumption are important problems facing the world at present. CO ₂ Is an important greenhouse gas, how to effectively separate and trap CO ₂ Is 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 advantages of stability, high separation efficiency, low energy consumption, environmental friendliness, etc., and has attracted great attention and development in recent years, and is widely applied to the aspects of permeation gasification, gas separation, etc. Employed in gas separation techniquesSeparation membranes can be classified into inorganic membranes, organic membranes, and mixed matrix membranes, depending on the type of membrane material. Organic polymer films are widely used in industry due to their good processability, common organic polymer film materials are Polyimide (PI), self-microporous Polymer (PIM), polyethylene oxide (PEO), etc., but such materials are difficult to overcome the mutual constraint between permeability and selectivity (trade-off effect), and the performance of the film is usually limited below the Robeson upper bound; inorganic membranes have been the focus of membrane technology research with excellent separation properties, thermal stability, and chemical stability, however, the cost is high and the large-scale preparation is difficult to prevent further development of inorganic membranes. To address these problems, researchers have attempted to combine the low cost, easy-to-film advantages of organic polymer films with the high performance advantages of inorganic films, the most common strategy being to prepare mixed matrix films (Mixed Matrix Membranes, MMMs).

The mixed matrix membranes are directed to polymers to which inorganic or organic materials are added to enhance the permeability and selectivity of the membrane. In recent years, various materials such as inorganic oxides, carbon materials, zeolites, etc., and newly developed microporous molecular sieve materials such as metal-organic frameworks (MOFs), covalent Organic Frameworks (COFs), microporous Organic Polymers (MOP), etc., have been used to prepare mixed matrix membranes. The permeability of the mixed matrix membrane is improved due to the addition of the microporous solid filler, but the selectivity is reduced along with the mixed matrix membrane; methods such as filler engineering (small molecule surface modification and polydopamine modification) and polymer modification (functional group introduction) have been proposed to improve the selectivity of mixed matrix membranes, but the permeability is usually reduced to different degrees; in addition, interfacial defects between the organic polymer matrix and the solid filler particles can also affect the properties of the mixed matrix film. To solve this problem, researchers have proposed a method of preparing a mixed matrix film using in situ crosslinking of a polymer and a filler.

Disclosure of Invention

The invention aims at overcoming the defects in the prior art, and provides a preparation method and application of a mixed matrix membrane for realizing efficient gas separation through in-situ crosslinking. The method realizes filling in the same polymerization systemPreparing materials and matrixes and chemically crosslinking; wherein the rigidity is selected

As polymer matrix, and->

The filler is used as a porous polymer filler; in theory, after the two reaction media are mixed, the 3D-TB with unreacted amino groups on the surface can be subjected to in-situ crosslinking with a grown TB chain to complete grafting, and the 3D-TB@TB polymer obtained after polymerization is used for preparing MMMs. Compared with the original TB pure film or a simple 3D-TB/TB physical blend 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 method for preparing a mixed matrix membrane for efficient separation of gases by in situ crosslinking, the method comprising the steps of:

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

wherein, 5-8 mL DMM is added to each 1g aromatic polyamine compound;

the aromatic polyamine compound is as follows:

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

(2) Preparation of Polymer Filler 3D-TB: under the conditions of a protective gas atmosphere and an ice water bath, trifluoroacetic acid (TFA) is added into the raw material mixed solution A obtained in the step (1), after the TFA is added, an ice water bath is removed, and stirring reaction is carried out for 12-24 hours at room temperature, so that a 3D-TB mixed solution is obtained;

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

(3) Preparing a polymer matrix raw material liquid B: under the condition of a protective gas atmosphere and ice water bath, uniformly dispersing aromatic diamine in dimethoxy methane (DMM) to obtain a raw material mixed solution B;

wherein, 5-8 mL DMM is added to each 1g aromatic diamine compound;

the aromatic diamine compound monomers are as follows:

(o-tolidine) or->

One of (1, 5-naphthalene diamine);

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

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

(5) In situ crosslinking of the polymer matrix with the filler: under the conditions of a protective gas atmosphere and an ice water bath, adding the polymer matrix mixed solution obtained in the step (4) into the 3D-TB mixed solution reaction system in the step (2), removing the ice water bath after the matrix mixed solution is added, 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;

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-linked product mixture: immersing the 3D-TB@TB product mixed solution obtained in the step (5) in dilute ammonia water, filtering, washing the product 3D-TB@TB by using excessive deionized water until the pH value is neutral, and drying under the condition of vacuum at 60-80 ℃ to obtain a product;

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

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

the structure is as follows

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

(8) Preparation of the film: adding the dried polymer material into chloroform 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 for 12-36 hours at room temperature to obtain a film;

wherein the thickness of the film is 5-200 mu m;

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

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

wherein the shielding gas is argon or nitrogen, and is most preferably argon;

wherein the purity of the trifluoroacetic acid is 99.5%;

the application of the mixed matrix membrane for realizing high-efficiency gas separation by in-situ crosslinking is used for separating CO ₂ . Preferably separating and capturing CO from the mixed gas ₂ The method comprises the steps of carrying out a first treatment on the surface of the The mixed gas is CO ₂ /CH ₄ Mixed gas, CO ₂ /N ₂ And (3) mixing gas.

A polymer material obtained by in-situ crosslinking has the structural formula:

wherein Ar is ₁ Is an aromatic polyamine compound, ar ₂ Is an aromatic diamine compound which is used for preparing the catalyst,

is a repeating unit structure->

Ar as described ₁ The structural formula is as follows:

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

ar as described ₂ The method comprises the following steps:

(o-tolidine) or->

(1, 5-naphthalene diamine).

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

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

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

The invention has the beneficial effects that:

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

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

(3) The preparation method of the in-situ crosslinking 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 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, porous organic polymer 3D-TB, and polymer TB in example 1;

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

FIG. 3 is a Scanning Electron Microscope (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 in 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 5wt% 3D-TB@TB film, FIG. 6 (b) is a 10wt% 3D-TB@TB film, FIG. 6 (c) is a 20wt% 3D-TB@TB film, and FIG. 6 (D) is a 10wt% 3D-TB/TB film;

FIG. 7 is a gas separation performance histogram 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

Polymer and process for preparing same

Fillers, which cause in-situ cross-linking reactions between them to prepare MMMs with better interface compatibility; among them, the tegreth base polymers (TBs) having V-bridge bicyclo structure can be prepared from aromatic diamines, representing a group of high performance Polymers (PIMs) having intrinsic micropores, widely recognized as promising gas separation membrane materials; the research shows that when the aromatic diamine is changed into polyamine, the three-dimensional Tegler alkali type bridge porous network (3D-TBs) material can be prepared, and the material can obtain good CO through a physical mixing method ₂ /N ₂ MMMs of separation performance. In this study, rigidity

As polymer matrix, and->

The filler is used as a porous polymer filler; in theory, after mixing the two reaction media, 3D-TB with unreacted amino groups on the surface can be combined with the slowly generated TB chain, and the 3D-TB@TB mixture obtained after polymerization is used for preparing MMMs. Our hypothesis is that in situ crosslinking may enhance compatibility between the TB matrix and the 3D-TB filler, minimizing the formation of interface defects. For comparison, a simple physical mixing and casting method was used to prepare MMMs from TB matrix and 3D-TB filler by physical mixing, followed by CO ₂ /N ₂ MMMs prepared by binary mixed gas evaluation in CO ₂ The potential application in capturing and separating is found to effectively solve the problem of poor two-phase compatibility between the traditional membrane filler and the polymer matrix by an in-situ crosslinking method.

The invention is further illustrated by the following specific experimental procedures. The following examples are intended to illustrate the invention without further limiting it.

Example 1

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

(1) Preparing a filler raw material mixed solution: under the conditions of argon shielding gas atmosphere and ice water bath, taking 0.1g (0.263 mmol) of tetra (4-aminophenyl) methane (TAPM) as a monomer, adding the monomer into a dry 50mL three-neck flask, then adding 0.5mL of dimethoxy methane (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: under the conditions of argon shielding gas atmosphere and ice water bath, 7mL of trifluoroacetic acid (TFA) is added into the mixed solution obtained in the step (1), the ice water bath is removed after the TFA is completely added, the reaction system is stirred and reacts for 24 hours at room temperature, and the 3D-TB mixed solution is obtained through further reaction;

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

characterization is performed: precipitating the mixed solution in the step (2) in 50mL of dilute ammonia water (the concentration is 10%), washing the precipitated 3D-TB solid to be neutral, washing the solid with dichloromethane, acetone and methanol for 3 times in sequence, and drying the solid powder at the temperature of 60 ℃ in vacuum to obtain 3D-TB; the structural schematic diagram is shown as follows:

the 3D-TB powder was analyzed and FT-IR thereof was as shown in FIG. 1, 1322cm ^-1 And 1023cm ^-1 The absorption band appearing in the middle represents the C-N peak in the Taylor lattice alkali, which proves the formation of the bridge structure; furthermore, after 3D-TB formation, at 3400cm relative to the IR of monomeric TAPM ^-1 To 3200cm ^-1 The left and right characteristic bands correspond to a significant decrease in the strength of the aromatic amine stretch band, and do not disappear, indicating the presence of unreacted amino groups on the 3D-TB polymer surface; to further demonstrate this conclusion, XPS analysis was performed on 3D-TB powder, as shown in FIG. 2, with N-H bond energy still present after synthesis of the 3D-TB material, fully demonstrating the presence of some unreacted terminal amino groups; both characterization results demonstrate the successful synthesis of the porous organic polymeric material 3D-TB with unreacted terminal amino groups present on the material surface;

in addition, SEM analysis was performed on 3D-TB material, as shown in FIG. 3, 3D-TB had a particle size of about 90-100 nm; by N at 77K ₂ Adsorption and desorption isotherm analysis of specific surface area of 3D-TB (FIG. 4), specifically, 3D-TB has a large specific surface area of 529m ² g ^-1 The method comprises the steps of carrying out a first treatment on the surface of the TGA results show that 3D-TB remains stable up to 400 ℃ (fig. 5), with good thermal stability;

(3) Preparing a polymer matrix raw material liquid: under the conditions of argon shielding gas atmosphere and ice water bath, 0.9g (4.24 mmol) of o-tolidine (OT) is taken as a monomer, and is added into a dry 50mL three-neck flask, then 4.5mL of Dimethoxymethane (DMM) is added, and magnetic stirring is carried out for 0.5h, so as to obtain a mixed solution;

(4) Preparation of TB polymer matrix mixture: under the conditions of argon shielding gas atmosphere and ice water bath, adding 16mL of TFA into the raw material mixed solution obtained in the step (3), and magnetically stirring to promote the dissolution of OT monomers to obtain a mixed solution;

to obtain characterization data for TB polymers, the above reactions were treated differently:

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

analysis of TB Polymer FT-IR was as shown in FIG. 1 at 1322cm ^-1 And 1023cm ^-1 The absorption band appearing in between represents the C-N peak in the Taylor base, which demonstrates the formation of its bridge structure, indicating successful synthesis of the TB polymer material;

(b) Continuing the reaction: the mixed solution in the step (4) is kept in a solution state, and preparation is carried out for in-situ crosslinking in the step (5);

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

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

(6) Post-treatment of the cross-linked product mixture: precipitating the product mixed solution obtained in the step (5) in 75mL of dilute ammonia water (with the concentration of 10%), washing the product to be neutral, washing the product with absolute methanol for 3 times, and drying the product at the temperature of 80 ℃ in vacuum to obtain 10 weight percent of a 3D-TB@TB;

wherein, 10wt% is the percentage of TAPM monomer mass to total mass of TAPM+OT;

(7) Purification of the crosslinked product: 1g of the dried product obtained in the step (6) is weighed, and 10 weight percent of 3D-TB@TB is dispersed and dissolved in 5mL of chloroform (CHCl) ₃ ) Obtaining a viscous solution, stirring the viscous solution for 48 hours at room temperature, then precipitating the viscous solution in absolute methanol to obtain a filiform product of 10 weight percent_3D-TB@TB, filtering, continuously washing the filiform product with absolute methanol for 2 times, and drying the filiform product at the temperature of 80 ℃ in vacuum to obtain a product;

since the TB chain is crosslinked (grafted) in situ onto the 3D-TB and polymerization continues at the same time, it can be deduced that the structure of its crosslinked product is schematically shown in the following formula:

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

(9) Activation of the membrane: soaking the obtained film in absolute methanol for 12 hours to remove residual solvent, and then drying the film in a vacuum oven at 120 ℃ for 12 hours to obtain the film for gas separation test;

example 2

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

finally, obtaining an in-situ cross-linked mixed matrix membrane 5wt% 3D-TB@TB membrane, and carrying out a gas separation test on the obtained membrane;

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

example 3

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

finally, a 20wt% 3D-TB@TB film of an in-situ crosslinking mixed matrix film is obtained, and a gas separation test is carried out on the obtained film;

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

example 4

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

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

the 10wt% 3D-TB/TB mixed matrix film is prepared by a traditional method of physically blending a polymer matrix with a filler, and comprises the following steps:

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 ultrasonic and magnetic stirring in a solvent for 24 hours, adding 0.45g of the TB polymer matrix in the step (a) in the step (4) into the system, continuously stirring for 24 hours to obtain a viscous solution, and obtaining a 10wt% of a 3D-TB/TB mixed matrix film according to the preparation methods in the step (8) and the step (9) of the example 1;

wherein the pure TB film of example 4 and the 10wt% 3D-TB/TB mixed matrix film were prepared for comparative testing to demonstrate the superior performance of the in situ cross-linked mixed matrix film;

SEM analysis was performed on cross sections of the films (fig. 6), all x_3d-tb@tb films having a dense and integrated morphology. In particular for 10wt% 3D-TB@TB (FIG. 6 b), the filler is homogeneously surrounded by the polymer matrix, which means that the in situ cross-linking grafting reaction significantly enhances the matrix-filler interface; for a 10wt% _3D-TB/TB physical blend film (fig. 6D), although there is no apparent polymer wrapping at the interface, it also exhibits excellent filler/polymer adhesion, we attribute it to the tergler base functionalized backbone possessed by the 3D-TB filler and TB matrix, promoting good interface adhesion and compatibility between the polymer matrix and filler.

The gas properties of the resulting film are shown in FIG. 7, although CO of x_3D-TB@TB ₂ Permeability increases with loading of filler, but in CO ₂ /N ₂ Volcanic profile was clearly observed selectively and was significantly dependent on 3D-TB loading; furthermore, testing found a decrease in selectivity of the 20wt% _3d—tb@tb film, which may be due to the insufficient filling of the polymer chains and the aggregation of the filler at a filler loading of 20wt%, resulting in some non-selective voids in the film; thus, a 10wt% 3D-TB@TB film had the best gas separation properties, its CO ₂ The permeability (90.75 Barrer) was increased by 61% compared to the pure TB film (54 Barrer), CO ₂ /N ₂ Selectivity (35.75) was increased by 28% compared to pure TB membrane (27.8). (wherein the volume ratio of CO is 1:4) ₂ /N ₂ The gas mixture was used as test gas and a gas separation test was carried out 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 their mechanical properties for 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; of these, 5wt% 3D-TB@TB film (stretching force of 76.4 MPa) had better mechanical properties than pure TB film (stretching force of 60.3 MPa), and 10wt% 3D-TB@TB film (stretching force of 55.1 MPa) had better properties than 10wt% 3D-TB/TB film (stretching force of 53.2 MPa) prepared by physical mixing in the conventional way, as also demonstrated by breaking point strain; these data indicate that the 3D-TB filler and TB matrix combined by in situ cross-linking contributes to better, more efficient two-phase interfacial compatibility than traditional MMM. (tensile measurements were made at 5 mm/min under ambient conditions (50% relative humidity) using a microcomputer controlled electronic Universal tester (CMT 6104))

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 of base fillers (3D-TB) prepared by an in situ cross-linking polymerization process, wherein the TB chains are cross-linked (grafted) in situ onto the 3D-TB filler; the in situ cross-linked mixed matrix films were observed by SEM images to exhibit a dense morphology, wherein the 3D-TB filler was uniformly encapsulated by the polymer matrix, a phenomenon that could not be observed in films prepared by conventional physical mixing methods. 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 redispersion treatment, so that the whole preparation process of the material is easy to amplify; (2) The grafting reaction and the polymerization process of TB take place simultaneously, providing molecular level homogeneity for MMMs; (3) Grafting occurs at an early polymerization stage, the TB porosity is tightly connected with the internal 3D-TB porosity, an interconnected microporous network is formed in the whole MMM, and the interconnected microporous design not only effectively eliminates the gaps between the polymer and the filler interface, but also promotes the gas transportation in the MMM; the results reported by the invention will provide useful guidance for future development of TB-based MMM and other porous organic networks.

The invention is not a matter of the known technology.

Claims

1. The preparation method of the mixed matrix membrane for realizing high-efficiency gas separation through in-situ crosslinking is characterized by comprising the following steps:

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

wherein, 5-8 mL of dimethoxy methane is added to each 1g of aromatic polyamine compound;

the aromatic polyamine compound is as follows:

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

wherein, 30-80 mL of trifluoroacetic acid is added to each 1g of aromatic polyamine compound;

(3) Preparing a polymer matrix raw material liquid B: under the condition of a protective gas atmosphere and ice water bath, uniformly dispersing aromatic diamine in dimethoxy methane to obtain a raw material mixed solution B;

wherein, 5-8 mL of dimethoxy methane is added to each 1g of aromatic diamine compound;

the aromatic diamine compound monomers are as follows:

one of them;

(4) Preparing a polymer matrix mixed solution: under the conditions of a protective gas atmosphere and ice water bath, adding a trifluoroacetic acid 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 of trifluoroacetic acid is added to each 1g of aromatic diamine compound;

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

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

the structure is as follows

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

wherein the thickness of the film is 5-200 mu m; adding 5-10 mL of CHCl to 1g of polymer material ₃ ；

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

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

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

4. The use of a mixed matrix membrane for the efficient separation of gases by in situ crosslinking prepared according to the method of claim 1, characterized in that CO is separated and captured from the mixed gas ₂ The method comprises the steps of carrying out a first treatment on the surface of the The mixed gas is CO ₂ /CH ₄ Mixture gas or CO ₂ /N ₂ And (3) mixing gas.

5. A mixed matrix membrane for achieving efficient separation of gases by in situ crosslinking prepared by the method of claim 1.