The kinetics and controllability of the Ti[OCH2CCl3](4)-initiated atom transfer radical polymerization (ATRP) of n-butyl acrylate were investigated. Then, with Ti[OCH2CCl3](4) as the initiator, poly(epsilon-caprolactone)-block-poly(n-butyl acrylate) (PCL-b-PBA) copolymers were synthesized by the combination of the ring-opening polymerization (ROP) of epsilon-caprolactone and ATRP of n-butyl acrylate. With different sequential combinations of ROP and ATRP, three routes were used to synthesize PCL-b-PBA copolymers. The composition characterization results demonstrated that the first-ROP-then-ATRP route was most efficient; it was followed by the in situ ATRP and ROP route and then the first-ATRP-then-ROP route. Furthermore, with a Haake Rheomix reactor (Thermo Electron Corp., Karlsruhe, Germany), the PCL-b-PBA copolymers were in situ synthesized in a poly(methyl methacrylate) matrix. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1958-1966, 2010