Synthesis of asymmetric difunctional initiators and their use in the preparation of block copolymers via ATRP and SFRP

Novel asymmetric difunctional initiators 2-phenyl-2-[(2,2,6,6-tetramethylpiperidino)oxy]ethyl 2-bromo-2-methyl propanoate and of 2-phenyl-2-[(2,2,6,6-tetramethylpiperidino)oxy]ethyl 2-bromo propanoate were synthesized in a three-step reaction sequence and used in atom transfer radical polymerization (ATRP) of methyl methacrylate or tert-butyl acrylate leading to corresponding polymer with tempo moiety as chain end. These polymers were found to be efficient initiators for stable free radical polymerization (SFRP) of styrene. 1H NMR and g.p.c. studies of the obtained polymers show that block copolymers are readily formed as a result of combination of ATRP and SFRP mechanisms.