The synthesis of comb block copolymers by ring opening metathesis polymerization (ROMP), ring opening polymerization (ROP), and atom transfer radical polymerization (ATRP) is described. Block copolymers were synthesized by the ROMP of oxanorbornene and norbornene monomers followed by hydrogenation of the olefins along the backbone. One block of these diblock copolymers possessed initiators either for the ROP of (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione or the ATRP of butyl acrylate. The synthesis and characterization of comb polymers with arms composed of poly(lactic acid) and poly(butyl acrylate) are described. These polymers had well-defined peaks in the size exclusion chromatography spectra which indicated that no homopolymers were synthesized. A comb block copolymer with polymeric arms of poly(styrene-b-vinylpyridine) is described. Vinylpyridine was polymerized from a comb polymer with poly(styrene) arms by ATRP at high dilution of the comb polymer. (C) 2011 Elsevier Ltd. All rights reserved.