Synthesis And Application Of Cyclotriphosphazene-Based Microporous Organic Polymers

Microporous organic polymers are a new type of porous materials, which have been widely used in the energy sources, gas storage and separation, heterogeneous catalysis, and chemical sensors and biosensors due to their good chemical and physical stability, high specific surface areas, and well-developed porous structures.In recent years, cyclotriphosphazene based microporous organic polymers have attracted an enormous attention because of their excellent thermal stability and flammability. In this thesis, a series of novel cyclotriphosphazene based microporous organic polymers have been synthesized through a one-pot condensation polymerization of aldehyde-containing cyclotriphosphazenes and melamine in DMSO solvent. In addition, CO₂ adsorption capacities of these polymers were also evaluated.The corresponding researches are listed below:（1） Synthesis and characterization of aldehyde-containing cyclotriphosphazene monomers. Three aldehyde-containing cyclotriphosphazene monomers, including dialdehyde, tetra-aldehyde, and hexa-aldehyde groups, were prepared by nucleophilic substitution reaction of hexachlorocyclotriphosphazene and p-hydroxy benzaldehyde and/or 2,2′-dihydroxy diphenyl. The as-synthesized monomers were characterized by FT-IR and NMR spectroscopies.（2） Synthesis and application of cyclotriphosphazene-based microporous organic polymers. A series of cyclotriphosphazene based microporous organic polymers have been prepared through a one-pot condensation polymerization of aldehyde-containing cyclotriphosphazenes and melamine in DMSO using the Schiff-base reaction. The assynthesized polymers were characterized by the FT-IR, MAS NMR, N₂ adsorption,SEM, and TEM techniques. The N₂ adsorption-desorption isotherms indicated that the dialdehyde-based polymer possessed a specific surface area of 884 m² g^-1, a total pore volume of 0.419 cm³ g^-1 and a micropore volume of 0.343 cm³ g^-1; the tetra-aldehyde based polymer possessed a specific surface area of 579 m² g^-1, a total pore volume of2.305 cm³ g^-1 and a micropore volume of 0.102 cm³ g^-1; the hexa-aldehyde based polymer possessed a specific surface area of 328 m² g^-1, a total pore volume of 0.850cm³ g^-1 and a micropore volume of 0.079 cm³ g^-1. CO₂ adsorption tests indicated that the dialdehyde-based polymer possessed the highest CO₂ adsorption capacities of 3.32 mmol g^-1（298 K） and 4.05 mmol g^-1（273 K）, respectively, followed by the hexaaldehyde based polymer(2.62 mmol g^-1, 273 K) and the hexa-aldehyde basedpolymer(2.09 mmol g^-1, 273 K).