Polyether-based thermoplastic polyurethanes. I. Effect of the hard-segment content



A series of Polyether-based thermoplastic polyurethanes, varying in hard-segment content between 20 and 80 wt. %, was prepared using an (oxypropylene-oxyethylene) diol of Mn = 2000 as the soft segment and 4,4′-diphenylmethane diisocyanate extended with 1,4-butanediol as the hard segment. Physical-mechanical, dynamic-mechanical, and specific heat (DSC) data are used to elucidate the mechanical and morphological behavior of these materials. The polyurethanes varied from soft elastomeric (continuous soft phase) to high-modulus plastic (continuous hard phase) and showed changes in their tensile properties at about 60% hard-segment content, possibly due to phase inversion.