Development of a universal alkoxyamine for "living" free radical polymerizations

Examination of novel alkoxyamines has demonstrated the pivotal role that th e nitroxide plays in mediating the "living" or controlled polymerization of a wide range of vinyl monomers. Surveying a variety of different alkoxyami ne structures led to alpha-hydrido derivatives based on a 2,2,5-trimethyl-4 -phenyl-3-azahexane3-oxy,1, skeleton which were able to control the polymer ization of styrene, acrylate, acrylamide, and acrylonitrile based monomers. For each monomer set, the molecular weight could be controlled from 1000 t o 200 000 amu with polydispersities typically 1.05-1.15. Block and random c opolymers based on combinations of the above monomers could also be prepare d with similar control.:In comparison with 2,2,6,6-tetramethylpiperidinoxy (TEMPO), these new systems represent a dramatic increase in the range of mo nomers that can be polymerized under controlled conditions and overcome man y of the limitations associated with nitroxide-mediated "living" free radic al procedures. Monomer selection and functional group compatibility now app roach those of ATRP-based systems.