Effect Of Different Initiation Methods On Properties Of Imprinted Polymers Prepared By Suspension Polymerization

Photo-activated polymerization technology refers to a method in which an initiator is activated to a free radical to initiate polymerization of an ethylenic monomer molecule under light conditions to form a solid product.Compared with the traditional thermal initiation polymerization technology,it is an environmentally friendly green polymerization technology that has the advantages of fast reaction speed and energy saving.Photo-activated RAFT polymerization combines the advantages of photo-activation technology and RAFT polymerization to rapidly prepare imprinted polymers with good properties.Although our team's previous research found that the MIP performance of photo-activated preparation is superior,there is no report on the effects of photo-activation and thermal initiation on MIP performance.Therefore,this study uses 2,4-dichlorophenoxyacetic acid(2,4-D)as a template to study the chemical,morphological and adsorption properties of MIP prepared by photo-activation/thermal initiation of RAFT suspension polymerization under the same conditions.The main research work is as follows:(1)Optimization of LMIP conditions for visible light activated RAFT suspension polymerization:The experimental results show that LMIP has a higher yield and uniform particle distribution and good adsorption properties at a molar ratio of2,4-D:MAA:EGDMA=0.30:1.20:3.60 and suspension polymerization for 180.0 min.Compared with traditional suspension polymerization,RAFT suspension polymerization has better MIP performance under optimized conditions,indicating that RAFT reagent plays a key role in the polymerization process.(2)Physical characterization of LMIP and HMIP:FT-IR,SEM,Malvern laser particle size analysis and Specific surface pore size analysis showed that the two MIPs prepared by RAFT suspension polymerization were rough surface microspheres with similar functional group structure and the big specific surface area(LMIP=406.68 m~2/g,HMIP=464.43 m~2/g),wherein the average particle size of LMIP(135?m)is larger than the average particle size of HMIP(66?m).(3)Adsorption performance of LMIP and HMIP:Isothermal static adsorption shows the difference in binding ability between MIP and NIP.Dynamic adsorption shows that HMIP reaches adsorption equilibrium earlier than LMIP,indicating that the former has a higher adsorption rate than the latter.In the isothermal model,LMIP is more inclined to the Langmuir model,HMIP is more consistent with the Freundich model,Scatchard model indicates that LMIP is an adsorption(specificity),and HMIP has two kinds of adsorption(non-specificity and specificity).The kinetic model shows that HMIP/LMIP is consistent with pseudo-secondary kinetics,and the intraparticle diffusion model indicates the multistep nature of the adsorption process.Variable temperature static adsorption and repetitive adsorption experiments show that the adsorption capacity of MIP and NIP is stable.(4)Selective adsorption and practical applications of LMIP and HMIP:HMIP/LMIP maintains high adsorption capacity for 2,4-D in competitive adsorption with 2,4-D and its structural analogs.The adsorption experiment of environmental water shows that both MIP can effectively identify and adsorb trace amounts of 2,4-D in environmental water.The adsorption performance of HMIP is better than LMIP.In summary,this experiment established a method for preparing MIP by visible light activation/thermal initiation RAFT suspension polymerization using ethyl acetate as porogen,which provides reference for monitoring environmental water.