Block copolymers of p-methoxystyrene (MOS) and styrene (St) with cyclohexene oxide (CHO) were prepared by sequential atom transfer radical polymerization and promoted cationic polymerization. In the first step, bromine terminated polyMOS and polySt were obtained by ATRP of the corresponding monomers at 115 degrees C for 5 h by using (1-bromoethyl) benzene (1-(PE)-Br), as an initiator, CuBr as a catalyst and 4-4'-di-(5-nonyl)-2,2'-bipyridine (dNbipy) as a complexing ligand. Polymeric radicals formed by the same radical generation process of ATRP were successively oxidized to the corresponding carbocations to initiate the polymerization of cyclohexene oxide. Block copolymer formation was evidenced by H-1-NMR and gel permeation chromatography (GPC) measurements. (C) 1999 Elsevier Science Ltd. All rights reserved.