The Design,Synthesis And Application Of Functional Initiator For Atom Transfer Radical Polymerization

As the most widely used method in controlled polymerization systems,atom transfer radical polymerization(ATRP)can realize the functionalization of polymer chain ends and the precise regulation of polymer structure,molecular weight and molecular weight distribution.With the development of the application field of ATRP technology,it is necessary to have a deeper understanding the polymerization process.Moreover,the monitoring of the polymerization process is of great significance for the safety of polymerization industrial.The traditional methods are unable to simultaneous achieve molecular level monitoring and reflect the dynamic changes of the polymerization process quickly and accurately.Therefore,the development of a noninvasive and sensitive in situ monitoring method is of great significance for the study of polymerization mechanism and kinetics of ATRP.In this thesis,a series of functional ATRP initiators were designed and synthesized by combining the tetrastyrene group with the traditional ATRP initiator,and a visualization method for in-situ monitoring of ATRP polymerization process was developed by virtue of its unique aggregation induced emission(AIE)property in situ monitoring of copper catalytic and photocatalytic ATRP polymerization process,respectively.The specific research work is as follows:(1)Preparation of bifunctional atom transfer radical polymerization initiatorA series of alkyl halides containing tetrastyrene group with AIE characteristics were prepared by combining the tetrastyrene group(TPE)with the traditional ATRP initiator(Ethyl ?-bromoisobutyrate and Ethyl ?-bromophenylacetate).The product was characterized by ultraviolet visible absorption spectrum,nuclear magnetic resonance,fluorescence spectrum and quantum chemical calculation.All the results showed that these synthetic initiator have AIE characteristics and can also be used as ATRP initiator.(2)In-situ monitoring of copper-catalyzed ATRP processFunctional initiators were first used for mornitoring copper-catalyzed ATRP.The obtained polymer molecular weight linear increased with the increase of monomer conversion,and the molecular weight distribution is narrow.The fluorescence intensity of the polymerization system was sensitive to the change of viscosity and was linearly related to the increase of molecular weight.Compared with physical blending,the method of chemical connection is more sensitive to the change of perceived environmental viscosity.These results indicate that the method we designed can be used for the in-situ visually monitoring copper catalyzed ATRP polymerization process.In addition,we also studied the monitoring effect on ppm level copper catalyzed ATRP(ICAR-ATRP)polymerization process.(3)In-situ monitoring of photocatalytic ATRP processMetal-free photocatalytic ATRP was also performed with the functional initiator.In addition to AIE character,the TPE group is also photosensitive and can activate the initiator for ATRP under light.The results show that the polymer molecular weight increases linearly with the monomer conversion,which exhibit the character of controlled radical polymerization.Moreover,the change of fluorescence intensity with monomer conversion also indicated that the photocatalytic ATRP system can be visually monitored in-situ.