Preparation Of PI/MOF-808 Mixed Matrix Membrane By Electrospinning And Its Properties

Polyimide(PI)is the polymer with outstanding thermal stability and excellent comprehensive performance.It is widely used in daily life,industrial production,national defense and aerospace and other fields.Electrostatic spinning technology can produce continuous nano-scale fibers,the operation process is convenient,and the preparation raw materials are very diverse.The preparation of PI fiber film by electrospinning(microstructure is nanometer fiber,macrostructure is film)can greatly improve the specific surface area and liquid absorption rate of PI film,but because the fibers are scattered together,the mechanical properties Greatly reduced,the application is limited,how to improve its mechanics is currently a problem we encountered.Metal organic framework mate-rials(MOFs)are currently very popular porous materials.Compared with traditional porous materials,they have larger specific surface area and higher porosity.They have unique applications in gas separation,catalysis and purification.It has the characteristics of organic materials and inorganic materials,and is often used as an additive to prepare composite materials.The introduction ofMOFs improves the loose fiber connection and improves the overall performance of PI fiber films.The main research contents and results are as follows:(1)Using pyromellitic dianhydride(PMDA)and 4,4’-diaminodiphenylether(ODA)as raw materials,PI nanofiber film(microstructure is fiber and macrostructure is film)is prepared by electrospinning method).Explore the effects of solvent solid content and electrospinning process parameters on fiber morphology.The fiber morphology can be controlled by changing the process parameters.(2)Under the electrostatic spinning process,explore the effect of PI precursor polyamic acid(PAA)solution on PI fiber structure and performance.The results sh-ow that the solvent directly affects the molecular weight of PAA.During the electrospinning process,due to the different molecular weight,the tensile effect of the electric field force is also different.Furthermo.re,the order,thermal stability and ten-sile strength of the PI fiber film also vary Change(3)Amide solvents with different sizes were mixed with formic acid as solvent template to prepare MOF-808 by solvothermal method.The results show that the smaller the solvent scale is,the larger the specific surface area of the MOF-808 sample and the stronger the adsorption performance will be.When the formamide/formic acid mixed solution is used as the solvent template,MOF-808 has the smallest aperture and its size is 1.19nm,the specific surface area is the largest,reaching to 1625 m2·g-1.(4)Introduce MOF-808 into PAA by in-situ polymerization method,change the amount of addition and prepare PI/MOF-808 mixed matrix film by electrospinning method,successfully make the cross-linking point between the fibers,the order degree of the film and The crystallinity increases,the mechanical properties increase,and the thermal stability decreases slightly.When the amount of crystal added is 0.5%,the comprehensive performance of the mixed matrix membrane is the best.