This article reports the results of experiments to synthesize a family of copolymers based on polyacrylamide (PAAM), poly(ethylene oxide) (PEO), and poly(propylene oxide) (PPO) to obtain PAAM-g-PEO and PAAM-g-PPO copolymers with varied grafted chain lengths and contents. The influence of the chemical structure, composition, and molecular architecture on the drag-reduction properties was evaluated. The PAAM-g-PEO systems were prepared by solution polymerization using hydrogen peroxide as initiator, whereas the PAAM-g-PPO systems were obtained by micellar polymerization using potassium persulfate as initiator and sodium dodecyl sulfate as surfactant agent. The synthesized polymers were characterized by carbon-13 nuclear magnetic resonance (13 C-NMR) and size-exclusion chromatography. The drag-reduction tests were carried out in a capillary viscosimeter in bench scale, and the performance was expressed in terms of drag-reduction percentage (%DR). The results suggest that, a determined chemical structure for each copolymer family evaluated probably promotes the ideal conformation of the chains under flow, favoring each polymer's drag-reduction action. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 2502-2510, 2011