Butadiene was polymerized with water-soluble 4,4’-azobis(amidinopropane)dihydrochloride initiator in an ethanol-water medium at 60 degrees C. Important variables, such as the initiator concentration, monomer concentration, solvency, and polymerization time and temperature were studied. C-13-NMR studies showed that no observable chain transfer to ethanol occurred during the polymerization. The conversion of monomer to polymer was significantly increased while maintaining a relatively narrow molecular weight distribution by intermittent feed of the initiator. The amidino end-groups of the polymer were transformed into amino groups by reduction using lithium aluminum hydride in THF, so that amine-terminated polybutadiene was obtained. The amino functionality of the polybutadiene was determined by titration to be 2.0.