A series of segmented poly(urethane-urea) polymers have been synthesized varying the hard segments content, based on the combination of polycaprolactone diol and aliphatic diisocyanate (Bis(4-isocyanatocyclohexyl) methane), using diamine (1,4-Butylenediamine) as the chain extender. The microstructure and properties of the material highly depend on the hard segments content (from 14 to 40%). These PUUs with hard segment content above 23% have elastomeric behaviors that allow high recoverable deformation. The chemical structure and hydrogen bonding interactions were studied using FTIR and atomic force microscopy, which revealed phase separation that was also confirmed by DSC, dynamic-mechanical, and dielectric spectroscopy. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119:2093-2104, 2011