CN-117987999-B - Polyimide/ZIF-8 composite nanofiber membrane containing imidazole ring, and preparation method and application thereof

CN117987999BCN 117987999 BCN117987999 BCN 117987999BCN-117987999-B

Abstract

The invention provides an imidazole ring-containing polyimide/ZIF-8 composite nanofiber membrane, and a preparation method and application thereof, wherein the preparation method comprises the steps of preparing an imidazole ring-containing polyamic acid spinning solution; preparing an imidazole ring-containing polyamic acid nanofiber membrane by using the imidazole ring-containing polyamic acid spinning solution through an electrostatic spinning method, performing thermal imidization treatment on the imidazole ring-containing polyamic acid nanofiber membrane to obtain an imidazole ring-containing polyimide nanofiber membrane, repeatedly dipping the imidazole ring-containing polyimide nanofiber membrane in a ZIF-8 solution for a plurality of times, and drying to obtain the imidazole ring-containing polyimide/ZIF-8 composite nanofiber membrane. According to the polyimide/ZIF-8 composite nanofiber membrane containing the imidazole rings, the ZIF-8 is anchored on polyimide fibers through the effect of positive ions and pi, so that the binding force between polyimide and ZIF-8 is effectively improved.

Inventors

XIE FAN
WEI HAITAO
LU ZHAOQING
Dai Xiyi
LIU QIAOLING
SHANG YUXUAN
LIU TAO

Assignees

陕西科技大学

Dates

Publication Date: 20260508
Application Date: 20240129

Claims (7)

1. The preparation method of the polyimide/ZIF-8 composite nanofiber membrane containing the imidazole ring is characterized by comprising the following steps of: S1, sequentially adding diamine monomers and dianhydride monomers into N, N-dimethylformamide, and stirring for reaction to obtain an imidazole ring-containing polyamide acid spinning solution, wherein the diamine monomers are a mixture of imidazole ring-containing diamine and imidazole ring-free diamine, and the molar ratio of the imidazole ring-containing diamine to the imidazole ring-free diamine is (1-4) (6-9); S2, preparing an imidazole ring-containing polyamic acid nanofiber membrane by using the imidazole ring-containing polyamic acid spinning solution through an electrostatic spinning method; S3, performing thermal imidization treatment on the polyamide acid nanofiber membrane containing the imidazole ring to obtain a polyimide nanofiber membrane containing the imidazole ring; S4, dipping the polyimide nanofiber membrane containing the imidazole ring in ZIF-8 solution and water for a plurality of times to obtain a polyimide nanofiber membrane containing the imidazole ring and growing ZIF-8, and drying to obtain the polyimide/ZIF-8 composite nanofiber membrane containing the imidazole ring; The ZIF-8 solution is prepared by liquid phase direct synthesis, specifically, soluble zinc salt and 2-methylimidazole are added into a solvent, and stirring reaction is carried out to prepare the ZIF-8 solution; in the preparation process of the ZIF-8 solution, the molar ratio of the concentration of zinc ions in the soluble zinc salt to 2-methylimidazole and the solvent is 1:4 (400-2000).
2. The preparation method of the imidazole ring-containing polyimide/ZIF-8 composite nanofiber membrane is characterized in that dianhydride monomer is one or a mixture of more of pyromellitic anhydride, hexafluorodianhydride and 3,3', 4' -benzophenone tetracarboxylic dianhydride in any proportion, imidazole ring-containing diamine is 2- (4-aminophenyl) -5-aminobenzimidazole, and imidazole ring-free diamine is one of 4,4' -diaminodiphenyl ether, biphenyl diamine and bisphenol A diamine.
3. The preparation method of the imidazole ring-containing polyimide/ZIF-8 composite nanofiber membrane according to claim 1, wherein in the step S1, the reaction temperature is 0-25 ℃ and the reaction time is 4-6 hours in the stirring reaction process of diamine monomers and dianhydride monomers.
4. The preparation method of the imidazole ring-containing polyimide/ZIF-8 composite nanofiber membrane according to claim 1, wherein in the step S2, the spinning voltage of electrostatic spinning is 15-20 kV, the flow rate of spinning solution is 0.010-0.017 mL/min, the distance between a needle head and a receiving plate is 10-20 cm, and the time of electrostatic spinning is 20-40 min.
5. The preparation method of the imidazole ring-containing polyimide/ZIF-8 composite nanofiber membrane according to claim 1, wherein in the step S3, the thermal imidization process is specifically that the temperature is raised to 100-150 ℃ at the temperature rise rate of 5-10 ℃ per minute, the temperature is kept for 30-60min, then the temperature is raised to 200-250 ℃ at the temperature rise rate of 5-10 ℃ per minute, the temperature is kept for 30-60min, and finally the temperature is raised to 300-350 ℃ at the temperature rise rate of 5-10 ℃ per minute, and the temperature is kept for 30-60 min.
6. An imidazole ring-containing polyimide/ZIF-8 composite nanofiber membrane, which is characterized by being prepared by the method according to any one of claims 1-5.
7. The use of the polyimide/ZIF-8 composite nanofiber membrane containing imidazole rings in the field of air filtration.

Description

Polyimide/ZIF-8 composite nanofiber membrane containing imidazole ring, and preparation method and application thereof Technical Field The invention belongs to the technical field of air filtering materials, and relates to an imidazole ring-containing polyimide/ZIF-8 composite nanofiber membrane, and a preparation method and application thereof. Background With the development of urban and industrialized production, the air pollution problem is increasingly serious, and frequent haze weather and air pollution events bring serious threat to the health and life of people. Therefore, research and development of efficient air filtration technology and materials has become an urgent task. At present, the air filtration technology has been widely applied and popularized, including methods such as mechanical filtration, electrostatic adsorption, activated carbon adsorption, ultraviolet irradiation, ozone oxidation and the like. Meanwhile, research and development of novel air filtering materials are also hot spots for research, such as nano materials, porous materials, functional materials and the like, and the materials have the advantages of higher filtering efficiency, longer service life, lower energy consumption and the like. Polyimide (PI) is a high-performance material, and the nanofiber membrane with small diameter, large specific surface area, small pore diameter and high porosity can be prepared by an electrostatic spinning method, so that the air filtration performance of the fiber material can be greatly improved. In addition, the nano particles are introduced into the polymer, so that the filtration performance of the polymer can be improved by increasing the specific surface area and the space supporting effect, and the polymer is endowed with lower pressure drop. In recent years, some researches show that due to the characteristics of ultrahigh specific surface area, functional pore channels, high porosity, adjustable, stable and various structures and the like, metal organic framework polymers (MOFs) can realize high-efficiency capture of particles and other harmful gas pollutants through special open metal sites, functional groups and surface charges besides size filtration. However, the interface force between MOFs and polyimide nanofibers is weak, MOFs are liable to fall off and agglomerate, and are difficult to be effectively and uniformly attached to the surface of a polyimide nanofiber membrane, and the functions of MOFs cannot be fully exerted. Therefore, how to effectively improve the interface combination between MOFs and polyimide fibers so as to enable the MOFs to be uniformly attached to the surfaces of the polyimide fibers is particularly important for preparing polyimide@MOFs composite materials. Disclosure of Invention Aiming at the problems in the prior art, the invention provides an imidazole ring-containing polyimide/ZIF-8 composite nanofiber membrane and a preparation method and application thereof, thereby solving the technical problems that MOFs and polyimide fibers have weak interfacial force, MOFs are easy to fall off and agglomerate and are difficult to be effectively and uniformly attached to the surface of the polyimide nanofiber membrane in the prior art. The invention is realized by the following technical scheme: The preparation method of the polyimide/ZIF-8 composite nanofiber membrane containing the imidazole ring comprises the following steps: s1, sequentially adding diamine monomers and dianhydride monomers into N, N-dimethylformamide, and stirring for reaction to obtain polyamide acid spinning solution containing imidazole rings, wherein the diamine monomers are a mixture of diamine containing imidazole rings and diamine not containing imidazole rings; S2, preparing an imidazole ring-containing polyamic acid nanofiber membrane by using the imidazole ring-containing polyamic acid spinning solution through an electrostatic spinning method; S3, performing thermal imidization treatment on the polyamide acid nanofiber membrane containing the imidazole ring to obtain a polyimide nanofiber membrane containing the imidazole ring; And S4, sequentially dipping the polyimide nanofiber membrane containing the imidazole rings in ZIF-8 solution and water for a plurality of times to obtain a polyimide nanofiber membrane containing the imidazole rings, which grows with ZIF-8, and drying to obtain the polyimide/ZIF-8 composite nanofiber membrane containing the imidazole rings. Preferably, the molar ratio of the diamine containing imidazole ring to the diamine not containing imidazole ring is (1-4): 6-9. Preferably, the dianhydride monomer is one or a mixture of more than one of pyromellitic anhydride, hexafluorodianhydride and 3,3', 4' -benzophenone tetracarboxylic dianhydride in any proportion, the imidazole-containing diamine is 2- (4-aminophenyl) -5-aminobenzimidazole, and the imidazole-free diamine is one of 4,4' -diaminodiphenyl ether, biphenyl diamine and bisphenol A diamine.