Vinyl acetate and vinyl chloroacetate were copolymerized in the presence of a bis(trifluoro-2,4-pentanedionato)cobalt(II) complex and 2,2'-azobis(4-methoxy-2,4dimethylvaleronitrile) at 30 degrees C, forming a cobalt-capped poly(vinyl acetate-co-vinyl chloroacetate). The addition of 2,2,6,6-tetramethyl-l-piperidinyloxy after a certain degree of copolymerization was reached afforded 2,2,6,6-tetramethyl-1-piperidinyloxy-terminated poly(vinyl acetate-co-vinyl chloroacetate) (PVOAc-MI; number-average molecular weight = 31,000, weight-average molecular weight/number-average molecular weight = 1.24). A H-1 NMR study of the resulting PVOAc-MI revealed quantitative terminal 2,2,6,6-tetramethyl-l-piperidinyloxy functionality and the presence of 5.5 mol % vinyl chloroacetate in the copolymer. The atom transfer radical polymerization (ATRP) of styrene (St) was studied with ethyl chloroacetate as a model initiator and five different Cu-based catalysts. Catalysts with bis(2-pyridylmethyl)octadecylamine (BPMODA) or tris(2-pyridylmethyl)amine (TPMA) ligands provided the highest initiation efficiency and best control over the polymerization of St. The grafting-from ATRP of St from PVOAc-MI catalyzed by copper complexes with BPMODA or TPMA ligands provided poly(vinyl acetate)-graft-polystyrene copolymers with relatively high polydispersity (> 1.5) because of intermolecular coupling between growing polystyrene (PSt) grafts. After the hydrolysis of the graft copolymers, the cleaved PSt side chains had a monomodal molecular weight distribution with some tailing toward the lower number-average molecular weight region because of termination. (c) 2006 Wiley Periodicals, Inc.