The effect of Z-group modification on the RAFT polymerization of N-vinylpyrrolidone controlled by “switchable” N-pyridyl-functional dithiocarbamates

The ability of a RAFT agent to control the polymerization of a monomer is dictated by the structures of both the monomer and the RAFT agent. In this paper, the polymerization of N -vinylpyrrolidone was examined with a series of cyanomethyl N -aryl- N -pyridyldithiocarbamates [(4-R′Ph)N(py)C(S)SCH 2 CN] varying in the substituent (R′) at the 4-position on the phenyl ring. The polymerization of N -vinylpyrrolidone was best controlled when R′ was methoxy; one of the least active RAFT agents in the series. The preservation of RAFT agent functionality was demonstrated by chain extension experiments with further N -vinylpyrrolidone. Again best control again was found for the RAFT agent with R′ = MeOPh. The utility of this RAFT agent was also proved with the preparation of poly( N -isopropylacrylamide)- block -poly( N -vinylpyrrolidone).