The activation and deactivation of the chain-transfer agent were achieved by oxygen initiation and regulation with triethylborane under ambient temperature and atmosphere.The autoxidation of triethylborane overcame th...The activation and deactivation of the chain-transfer agent were achieved by oxygen initiation and regulation with triethylborane under ambient temperature and atmosphere.The autoxidation of triethylborane overcame the oxygen inhilbition and produced initiating radicals that selectively activate the chain-transfer agent for the chain growth or deactivate the active chain-end of polymer in controlled radical polymerization.Both activation and deactivation were highly efficient with broad scope for various polymers with different chain-transfer agents in both organic and aqueous systems.Oxygen molecule was particularly used as an external regulator to initiate and achieve the temporal control of both activation and deactivation by simply feeding the air.展开更多
Molecular oxygen is a radical scavenger in both conventional and controlled radical polymerization(CRP),resulting in many time-consuming methods for physically removing oxygen before the polymerization.Different appro...Molecular oxygen is a radical scavenger in both conventional and controlled radical polymerization(CRP),resulting in many time-consuming methods for physically removing oxygen before the polymerization.Different approaches have been developed to have oxygen toleranee by chemically consuming or converting molecular oxygen into non-initiating species to address this issue.Recently,we propose another approach called oxygen initiation that directly transforms molecular oxygen into the initiating carbon radical in CRP.This feature article summarizes our rece nt developments in this direction.Oxyge n-initiated reversible additi on-fragmentation transfer(RAFT)polymerization has been successfully conducted using oxygen and trialkylborane as co-initiators under the ambient conditions and atmosphere without any prior degassed procedures.This gas-triggered initiation provides the opportunity for spatiotemporal control of the polymerization by molecular oxygen or air.Rationally synthesized alkylborane compounds could derive the predesigned structure of the initiating alkyl radical to minimize the side reacti ons and free polymer chai ns,achievi ng the synthesis of ultra-high molecular weight polymers.The challe nges and perspectives are also discussed in the end.展开更多
基金the National Natural Science Foundation of China(Nos.21704017,21871056,and 91956122).
文摘The activation and deactivation of the chain-transfer agent were achieved by oxygen initiation and regulation with triethylborane under ambient temperature and atmosphere.The autoxidation of triethylborane overcame the oxygen inhilbition and produced initiating radicals that selectively activate the chain-transfer agent for the chain growth or deactivate the active chain-end of polymer in controlled radical polymerization.Both activation and deactivation were highly efficient with broad scope for various polymers with different chain-transfer agents in both organic and aqueous systems.Oxygen molecule was particularly used as an external regulator to initiate and achieve the temporal control of both activation and deactivation by simply feeding the air.
基金We thank the financial support from State Key Laboratory of Molecular En gineering of Polymers,Departme nt of Macromolecular Science,Fudan University and the National Natural Science Foundation of China(Nos.21871056,21704017,and 91956122).
文摘Molecular oxygen is a radical scavenger in both conventional and controlled radical polymerization(CRP),resulting in many time-consuming methods for physically removing oxygen before the polymerization.Different approaches have been developed to have oxygen toleranee by chemically consuming or converting molecular oxygen into non-initiating species to address this issue.Recently,we propose another approach called oxygen initiation that directly transforms molecular oxygen into the initiating carbon radical in CRP.This feature article summarizes our rece nt developments in this direction.Oxyge n-initiated reversible additi on-fragmentation transfer(RAFT)polymerization has been successfully conducted using oxygen and trialkylborane as co-initiators under the ambient conditions and atmosphere without any prior degassed procedures.This gas-triggered initiation provides the opportunity for spatiotemporal control of the polymerization by molecular oxygen or air.Rationally synthesized alkylborane compounds could derive the predesigned structure of the initiating alkyl radical to minimize the side reacti ons and free polymer chai ns,achievi ng the synthesis of ultra-high molecular weight polymers.The challe nges and perspectives are also discussed in the end.
