Construction Of Thermo-regulated Phase Separable Catalysis Systems Based On ICAR ATRP

Transition metal catalyst mediated atom transfer radical polymerization?ATRP?is the most efficient and widely applied method for“living”radical polymerization.However,transition metal catalyst contamination in the polymerization product not only wastes the natural resources but also limits its applications in the electronic and biomedical material fields.Therefore,how to reduce the metal catalyst residual efficiently is still a hot topic till now.As the reports showed that thermoregulated phase separated catalysis?TPSC?strategy is an efficient and convenient method to separate and recycle the catalyst in situ combining homogeneous reaction with heterogeneous separation just by changing the temperature while keeping the features of“living”/controlled radical polymerization and low catalyst residual.The main purpose of this thesis is to construct highly efficient TPSC systems to achieve in situ separation and recycling of catalyst based on initiators for continuous activator regeneration ATRP?ICAR ATRP?.The main research contents and conclusions are as follows:Systems ?:Construction of Fe???-mediated and TPSC-based ICAR ATRP in the PEG-200/p-xylene biphasic system.This chapter has established a TPSC system that composes of PEG200 and p-xylene and successfully separated and recycled the iron catalyst in situ for the first time.The TPSC-based ICAR ATRP system was established by using methyl methacrylate?MMA?as the model monomer,FeCl₃·6H₂O as the catalyst,TBABr as the ligand,AIBN as the reducing agent and EBPA as the initiator,respectively.When heated to 70 ^oC the polymerization system became homogeneous and backed to separate two phases in situ at room temperature:PEG200 phase including iron catalyst/ligand and p-xylene phase involved in polymers just by simple decantation.The PEG200 phase could be used to recatalyze a new ICAR ATRP just by adding fresh monomer,initiator,reducing agent and p-xylene.In addition,this system still kept a controlled feature even if the catalyst phase was reused up to 10 times.Moreover,this polymerization system could be extended to other lipophilic monomers such as methyl acrylate?MA?,styrene?St?and tert-butyl acrylate?t BA?successfully.Systems ?:Construction of Cu???-mediated and TPSC-based ICAR ATRP based on thermoregulated poly?ionic liquid?macroligand.In previous reports,most catalyst recycling systems usually focused on the catalyst recycle,and ignored the recycle of the more expensive ligands with much more usage.Actually,both the activity of catalyst and“living”/controlled features of polymerization systems reduced with increase of the catalyst recycling times because of the inevitable transfer loss of catalyst and organic ligands during recycling process.In this chapter,we developed concept of thermoregulated poly?ionic liquid?macroligand for the first time,which was established by designing a thermoregulated ionic liquid monomer(MPEG₃₅₀-MA-IL)and a high activity ligand monomer?MA-LN?and then obtaining the Cu complex with this kind of macroligand?PILL?through radical copolymerization.The TPSC-based ICAR ATRP system could be constructed with benzene,and successfully realized the simultaneous separation and recycling of both Cu catalyst and macrolignd in situ.In addition,this system could be extended to other lipophilici monomers such as MA,St,BA.Importantly,highly efficiency of this polymerization was verified by experiments.The metal catalyst residual in polymer solution phase remained just about 1.5ppm,and the catalyst recycle efficiency kept 95%even the PILL and Cu catalyst was separated and reused beyond 10 times while not sacrificing the polymerization rate and the controllability over polymerization.Systems ?:Construction of Fe???-mediated and TPSC-based ICAR ATRP based on thermoregulated poly?ionic liquid?hybrid macroligand.Due to the unique advantages of Fe???-mediated ATRP in synthesizing biomedical materials,in situ separation and recycling of iron catalyst was spontaneously attracted special attention.Although we established an iron catalyst separation and recycling strategy as shown in system I,it is hard to recycle the catalyst and ligand simultaneously and therefore resulting deteriotation of controllability over polymerization after several recycling times due to the gradual loss of ligands in recycling process.Inspired by the strategy discussed in system ?,in this chapter,we designed and synthesized a thermoregulated poly?ionic liquid?hybrid macroligand?PILHL?complex with iron salt containing triphenylphosphine and tetrabutylphosphonium bromide groups,and built a TPSC system with benzene via iron-mediated ICAR ATRP of MMA successfully accompanying with explicitly separated phenomenon.