Controlled/living free radical polymerization of styrene and butyl acrylate was performed in bulk and emulsion using a reversible addition-fragmentation transfer (RAFT) process. The effect of the transfer agent to initiator ratio was explored in bulk and emulsion polymerizations. The effect of monomer addition was investigated in emulsion, and two different processes were used: batch and semicontinuous. Better control was obtained with the continuous addition of the monomers, resulting in clear films of the styrene-butyl acrylate copolymers. These copolymers were characterized and studied by size exclusion chromatography, scanning differential calorimetry, dynamic mechanical analysis, transmission electron microscopy, and simulation, indicating that the semicontinuous process produces copolymers with a block of styrene and a block of tapered random copolymer.