Controlled Synthesis Of Conjugated Microporous Polymers And Their Related Properties

Porous materials have applied in many fields, such as petrochemical industry, electronic chemistry and metallurgical industry. microporous organic polymers (MOPs) generally possess high surface area, good physicochemical stability and controllable pore size have attracted increasing attention. Recently, the excessive CO2 emission cause serious greenhouse effect, which makes rising attention on CO2 capture. The unique pores structure makes MOPs the great potential in the gas absorptive. Besides, the controllable pore size could enhance the affinity between the polymer and CO2 molecules.Because of the organic characters of MOPs, the properties of MOPs can be controlled by the monomers structures. Our thesis focuses on the substituted groups, morphology and conjugated structure of MOPs. We explore the relationship between properties of MOPs and MOPs performance. For example, we discuss the relationship between pore structure of MOPs and gas capture ability. The experiments of MOPs are useful to explore the strategies of concept of MOPs synthesis.There are five types of microporous Organic polymers (MOPs) based on the molecular structure:CMPs (conjugated microporous polymers), HCPs (hyper-crosslinked polymers), covalent triazine frameworks (CTFs), PIMs (polymers of intrinsic microporosity) and COFs (covalent organic frameworks). This thesis mainly focuses on covalent triazine frameworks and conjugated microporous polymers. We focus on the substituted groups, morphology and conjugated structure of MOPs. The main work includes the following aspects: (1) Four conjugated microporous polymers from 1,3,6,8-tetrabromocarbazole and its alkylated derivative has been synthesized via Suzuki cross-coupling polycondensation. The pore properties (pore size & surface area) of this kind of conjugated microporous polymers could be tuned by using either linker with different geometries or carbazole substituted with alkyl groups. These polymer networks are stable in common organic solvents and thermally stable.All of the polymers show high isosteric heats of CO2 adsorption (27.1?30.8 kJ mol-1) because the incorporation of nitrogen atoms into the skeleton of conjugated microporous polymers enhanced the interaction between the pore wall and CO2 molecules. The polymer PPTBC shows highly Brunauer-Emmet-Teller specific surface area up to 917 m2g-1 with a high CO2 uptake ability of 2.93 mmol g-1 at 1.13 bar/273 K. These data show that these materials would be potential candidates for applications in post-combustion CO2 capture and sequestration technology.(2)Four Nitrogen-rich conjugated microporous polymers have been synthesized via palladium-catalyzed Suzuki cross-coupling or Sonogashira polycondensation from diamino-grafted or azo-fused monomers. The surface area, pore size and morphology of the resulting polymers are closely related to the building blocks, and the azo-fused polymers with rigid conformation show enhanced surface area up to 1146 m2 g-1 compared with the diamino-grafted polymers. Azo-CMP1 with the highest surface area among the polymers shows a remarkable CO2 uptake of 3.72 mmol g-1 (1.13 bar/273 K) with a good CO2/N2 selectivity of 42.1:1 at 273 K. All of the polymers show high isosteric heats of CO2 adsorption (-30 kJ mol-1) because the incorporation of nitrogen atoms into the skeleton of the conjugated microporous polymers enhanced the interaction between the pore wall and the CO2 molecules. Due to the high surface area, the good physicochemical stability and the outstanding CO2 sorption performances, these nitrogen-rich polymer networks are promising candidates for potential applications in post-combustion CO2 capture and sequestration technology.(3)Three covalent triazine frameworks (CTFs) synthesized by CF3SO3H catalyzed trimerization reactions show properties quite alike to CMPs and this method avoids the use of noble metal catalysts. In this study, a series of novel fluorescent covalent triazine-based frameworks (F-CTFs) was prepared using different tetra-cyano compounds as the starting monomers. Both porosity and fluorescence properties of the F-CTFs could be adjusted by the monomer structure. Gas adsorption measurement revealed that F-CTFl with the largest surface area of 896 m2/g shows the highest CO2 uptake of 3.29 mmol/g at 273 K and 1.13 bar among the polymers. Taking advantages of their large surface areas and strong fluorescence, these F-CTFs could be used as efficient chemical sensing agents for various nitroaromatic compounds as well.