Synthesis Of Nitrogen-Rich Porous Ionic Polymers For Gas Adsorption And Lithium-Sulfur Battery

Porous ionic polymers(Porous ionic polymers,PiPs)are novel emerging functional organic polymers,which unite advantages of both porous polymers and ionic liquids.PiPs have the characteristics of electrification,porosity and high specific surface area.The ionic groups can be chemically grafted into the polymer backbone or covalently attached to a polymer framework.By regulating the structural units and counterions,the physical and chemical properties of PIPs can be easily modified.Moreover,the specific surface area,hydrophobicity and pore size of PIPs can also be tuned through counterions exchange.Designable and alternative ionic backbones broaden the application of PiPs which have potential applications in fields of catalysis,antibacterial and water purification.In this thesis,a variety of functionalized porous ionic polymers were designed and synthesized,including bipyridine porous ionic polymers and polypyrrole grafted MOF-based ionic porous materials.The applications of bipyridine based PiPs in adsorption and separation were studied.Furthermore,the performance of polypyrrole grafted MOF-based PiPs in Lithilm-sulfur batteray were demonstrated.This thesis contains two parts below:(1)Design and synthesis of ionic covalent triazine frame(ICTFs)porous polymer.Herein,we designed and synthesized few cyano-substituted bipyridine ionic liquids as precursors of ICTFs.ICTFs were synthesized from cyano-substituted bipyridine ionic liquids by programmed melting polymerization method.The cyano groups in bipyridine ionic liquids are self-polymerized into triazine groups weaving the pyridine skeleton into a porous network.The as-prepared ICTFs have a specific surface area and total pore volume of approximately 1000 m2 g-1 and 0.4582 cm3 g-1 respectively.The obtained ICTFs could be applied for the adsorption/separation of the mixed gases(CO2,SO2,NO and N2),and they showed the strong adsorption ability for CO2(4.87 mmol g-1),SO2(9.22 mmol g-1)and NO(4.05 mmol g-1)at room temperature.This unique design provides a new insight to prepare high-efficiency porous materials for CO2,SO2 and NO capture.(2)The porous ionic polymers which combines conductive polymer and MOFs material was designed and synthesized.A versatile strategy for a facile approach to chemical graft MOFs onto polypyrrole nanotubes(PPyNTs@MOFs)was designed and fabricated rationally by means of 1,4-dibromobutane linkage.Various MOFs arranged randomly close-packed on PPyNTs,including Co2+,Cu2+,Zn2+,Mn2+,Fe3+,Al3+,Ti4+,Cr4+,Zr4+and V4+,have been synthesized successfully.The as-prepared PPyNT@UIO-66 hybrids,used as a cathode carrier,exhibit excellent cyclic stability in Li-S batteries via strong physical and chemical adsorption/affinity with polysulfides.PPyNTs@UIO-66 retains the structural polarity of the metal oxide unit derived from the skeleton and the high porosity of the parent MOF.Compared with simple PPyNTs and UIO-66,it shows excellent electrochemical durability.At the scanning rate of 0.1C,the initial discharge energy density of PPyNTs@UIO-66-S positive electrode is 1225 mAh g-1.After 200 cycles,the discharge capacity is still 996 mAh g-1.