Novel thermoplastic polyhydroxyurethane elastomers as effective damping materials over broad temperature ranges

Non-isocyanate thermoplastic polyhydroxyurethane (PHU) elastomers were synthesized from cyclic carbonate aminolysis using polytetramethylene oxide (PTMO) as soft segment and divinylbenzene dicyclocarbonate and three diamine chain extenders as hard segment with a range of hard-segment content. Characterization was done via Fourier transform infrared spectroscopy, small-angle X-ray scattering (SAXS), uniaxial tensile testing, and dynamic mechanical analysis (DMA). SAXS reveals that these PHUs possess nanophase-separated morphology with 10-20 nm interdomain spacings. These PHUs display elastomeric response and tunable tensile properties with Young's modulus ranging from 27 to 200 MPa, tensile strength from 0.3 to 9.7 MPa and elongation at break ranging up to greater than 2000%. DMA reveals that nanophase separation in these PHUs is accompanied by broad interphases having a wide range of local composition; this nanophase separation differs significantly from that manifested by thermoplastic polyurethane elastomer (TPU) due to hydrogen bonding of hydroxyl groups in the hard segments to the PTMO soft segment. These PHUs show very good damping performance with tan delta >= 0.30 over broad temperature ranges (>= 60 degrees C), which are tunable through simple variation of hard segment content and chain extender structures. (C) 2016 Elsevier Ltd. All rights reserved.