The synthesis and characterization of new thermoplastic poly(carbonate-urethane) elastomers derived from HDI and aliphatic-aromatic chain extenders

New thermoplastic poly(carbonate-urethane) elastomers (TPCUs) were prepared by a one-step melt polymerization from 20-80 mol% poly(hexane-1,6-diyl carbonate) diol of (M) over bar (n) = 860 as a soft segment, hexane-1,6-diyl diisocyanate and 2,2'-[methylenebis(1,4-phenylenemethylenethio)]diethanol, 3.3'-[methylenebis(1,4-phenylenemethylenethio)]-dipropan-1-ol or 6.6'-[methylenebis(1,4-phenylenemethylenethio)ldihexan-l-oI (H) as new chain extenders at the NCO/OH molar ratio of 1 in the presence of dibutyltin dilaurate as a catalyst. The structures of the TPCUs were examined by FTIR spectroscopy, X-ray diffraction analysis, scanning electron microscopy and atomic force microscopy (AFM). The TPCUs were also characterized by physicochemical, thermal (by differential scanning calorimetry (DSC) and thermogravimetry) and tensile properties as well as Shore A/D hardness. The resulting TPCUs were colorless polymers, showing ordered structures including semicrystalline, with the highest ability to crystallize exhibited by the polymers derived from diol H. The polymers with the soft-segment content of 40-80 mol% (56.4-25.7 wt% of hard segments) exhibited a microphase separation shown by DSC and AFM. The TPCUs showed tensile strength in the range of 8.8-23.3 MPa and elongation at break in the range of 240-670%. (C) 2009 Elsevier Ltd. All rights reserved.