Preparation And Properties Of Conjugated Microporous Polymer By Emulsion Template Method

Conjugated microporous polymers(CMPs)are a class of organic porous polymers,combining ?-conjugated skeletons with permanent nanopores.As an emerging material platform,CMPs offer a high flexibility for the molecular design of conjugated skeletons and nanopores due to their highly designable structures,high specific surface area,good thermal stability and easy functionalization,CMPs thus have great potential for gas adsorption,light emitting,light harvesting,heterogeneous catalysis,electrical energy storage and sensor.CMPs are highly cross-linked rigid structures and generally they are insoluble and infusible solid powders,this causes difficulties for controlling their structures and further processing,such as coatings,films or blocks.Thus,it is necessary to develop proper methods for preparing CMPs materials efficiently.Recently,studies show that the processing difficulties in the preparation of CMPs materials have been effectively solved by using the pre-formed template method preparation strategy.In detailed,the precursor of the monomer containing CMPs material is preset in a certain shape and structure system,and then the polymerization is initiated and removed the template to obtain the CMPs material.Gel templates,hard templates and emulsion templates can be employed to prepare CMPs materials.Comparing with other methods,the emulsion template method is a relatively simple and easy to implement material processing,and it has the advantages of pre-controllable structure,low cost and environmental friendly in the preparation process.However,the preparation of-CMPs material requires high temperature conditions,and the emulsion belongs to a metastable system,which is a great challenge to the emulsion system.Unstable emulsion system during the polymerization process will cause problems,such as incomplete material structure,uneven pore structureand difficult control of fine structure.The stability of the emulsion system is the key effect in the material preparation process,it is also a challenge for preparaing CMPs by emulsion template method.Therefore,constructing a stable liquid-liquid interface and obtaining a high-stability emulsion template system is of great significance for the efficient and controllable preparation of CMPs materials.Based on the above research status and the long-term research work of high-stability emulsion system in our laboratory,this thesis work is dedicated to the controllable preparation of CMPs materials by emulsion template method.Based on the laboratory synthesis and amphiphilic studies of amphiphilic azobenzene compounds,a series of emulsion systems containing monomers for the preparation of CMPs were prepared,and the emulsion are stabile even under high temperature(at 80“C).On this basis,a series of CMPs containing macropores were prepared by emulsion template.More importantly,by regulating the stabilizer interface,the preparation of the monolith and the particle material can be controlled,and the the pore structure of the CMPs material can be controlled by changing the composition ratio of the emulsion.Moreover,the prepared CMPs exhibit good adsorption effects on dyes and antibiotics.Specifically,the following two aspects have been carried out:In the first part of the work,we synthesized the four amphiphilic azobenzene compounds,which can be used to emulsify the aqueous phase and oil phase including 1,3,5-tribromobenzene and 1,4-diethynylbenzene.CMPs materials were obtained by emulsion template at high temperature.It is also found that water content,triethylamine content,stabilizer content influence the stability and morphology of the emulsion,which in turn affects the microstructure and morphology of the CMPs.Most importantly,by simple protonation of the azobenzene stabilizer,the reversal of the emulsion from W/O type to O/W type can be achieved,thereby realizing the CMPs material from the monolith(CMP-M)to the microspheres(CMP-P).The emulsion system is stable throughout the reation process,the structure of the CMPs is intact,and the microscopic pore structure of the CMPs can be precisely controlled by changing the composition of the emulsion.The solid-state 13C NMR and FTIR test results show that the CMPs are successfully prepared.The TGA test shows that the CMPs have good thermal stability,indicating a high degree of polymerization.SEM,PXRD and TEM were used to characterize the morphology and microstructure of the material,and it was found that there were a large number of micropores about 1 nm,and the material have a certain degree of order.The CA test shows that strong hydrophobicity,and the mechanical experiments shows that the obtained CMPs have a certain compressive recovery.In the second part of the work,the performance of CMP-M on dye adsorption in organic solvents,adsorption of antibiotics in aqueous solution and separation of oil and water were studied.The adsorption kinetics and adsorption isotherm model of oil red 0 and ciprofloxacin in adsorption were studied,and it was found that the adsorption process of oil red O and ciprofloxacin by CMP-M accorded with pseudo-second-order kinetic and matched to the Freundlich model.This indicates that the active sites of CMP-M adsorbed oil red O molecules and ciprofloxacin molecules are not uniform,and the adsorption process is chemical adsorption of multi-molecular layers.The results show that the adsorption capacity of CMP-M on oil red O and antibiotics can reach 83.37 mg/g and 91.80 mg/g,which is due to the ?-? interaction between CMP-M and dyes and antibiotics.Moreover,the organic solvent in the aqueous phase can be quickly adsorbed and has good adsorption separation effect due to the hydrophobic and micro-mesopore-macroporous structure and compressibility of CMP-M.