Because of the presence of extensive H-bonding in the hard segments, polyureas are processed by solution techniques (e. g., dry spinning) by the use of relatively costly and environmentally unfriendly solvents. Thus, the objective of this research was to render polyureas melt processible, (i.e., to reduce their flow temperature, T(flow)) without compromising their excellent mechanical properties. We hypothesized and herein demonstrate that by using conventional chain extenders (CEs) in combination with small amounts of H-bond acceptor chain extenders (HACEs), the T(flow) of polyureas can be significantly reduced from similar to 230 to similar to 180 degrees C, and thus melt processible products with excellent mechanical properties can be obtained. We document the synthesis of conventional polytetramethylene oxide-based and novel polyisobutylene (PIB)-based polyureas with T(flow)s similar to 180 degrees C and excellent mechanicals by the addition of few percents of commercially available HACEs. Products were characterized by various techniques, including Instron (tensile strengths, elongations), durometer (Shore A Hardness), dynamic mechanical thermal analysis (T(flow)), and thermal gravimetric analysis (TGA) (thermal weight loss). According to TGA, a polyurea with T(flow) of similar to 180 degrees C did not degrade up to similar to 234 degrees C in air. A micromorphology for melt processible polyureas is proposed that emphasizes flexibilized hard segments in the presence of HACEs. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2461-2467, 2011