Preparation Of Covalent Organic Framework Materials And Studies On Their Gas Adsorption Properties

Covalent organic frameworks（COFs）are a class of nano organic porous materials with high specific surface area,uniformly distributed pores,and easy control on functionalization.They have great application potential in gas adsorption and other fields.In this thesis,several 2D and 3D COF materials were prepared.The gas adsorption properties were evaluated and a new kind of supramolecular polymers was prepared.The aim of this thesis is to provide new ideas and theoretical basis for the optimization of air-conditioning fresh-keeping polymer film packaging.The specific research contents and results are listed as follows:（1）Two 2D COF materials 2-1 and 2-2 were prepared by using solvothermal method,which were subjected to Fourier transform infrared spectroscopy（FT-IR）,X-ray diffraction（XRD）,and X-ray photoelectron spectroscopy（XPS）.The structures were also characterized by the solid nuclear magnetic carbon spectrum(¹³C CP/MAS NMR).Gas adsorption test showed that both of the prepared materials have good capability to adsorb gases.At 77 K and 1 bar,the adsorption capacity of material 2-1to hydrogen is 60 cm³/g,and the adsorption capacity of material 2-2 is 70 cm³/g;the carbon dioxide adsorption capacity of material 2-1 at 273 K and 298 K was 11.44cm³/g and 6.51 cm³/g,respectively,while that of the material 2-2 towards carbon dioxide was 12.45 cm³/g and 7.5 cm³/g,respectively.（2）Two 3D COF materials 3-4 and 3-5 were designed and fabricated,and the structures of the two materials were analyzed by Fourier transform infrared spectroscopy（FT-IR）,X-ray diffraction（XRD）and scanning electron microscopy（SEM）.Gas adsorption tests show that both of the three-dimensional materials have the ability to adsorb gases.At 298 K and 1 bar,the adsorption capacities of materials3-4 and 3-5 for CO₂ are 11.76 cm³/g and 7.89 cm³/g,respectively,and the adsorption amounts for O₂ are 4.10 cm³/g and 3.52 cm³/g,respectively.（3）A new type of supramolecular polymer crosslinked by metallacycle was designed and prepared.Two monomers M1 and M2 were synthesized for polymerization by several step reactions.A few polymers with adjustable molecular weight were prepared from these two monomers.The self-assembly of M2 with a Pt（II）complex furnished a diamond-shaped monomer M2-P60.A supramolecular polymer SP1 was then prepared by self-polymerization of M2-P60 and a supramolecular polymer SP2 was prepared by co-polymerization of M2-P60 and M1.The polymer and supramolecular polymer were characterized by gel permeation chromatography（GPC）and nuclear magnetic resonance（NMR）.These metallacycle-containing supramolecular polymers are expected to have good porosity and controllability,and thus have potential applications in air-conditioning preservation and other food or biological fields.