Morphology and properties of novel thermoplastic polyurethane elastomer

A series of novel thermoplastic polyurethane elastomers(TPUE) containing side ester groups which can be used as propeliam binder were synthesized from polyethylene/polypropylene adipate diol ( PEPA ), tetrahydrofuran/ethylene oxide copolyether ( PET ), isophorone diisocyanate ( IPDI ) and diethyl bis (Hydroxymethyl) malonate (DBM) as primary substances by melt pre-polymerization method. FTIR, GPC, DSC and tensile test were employed to characterize the structures and properties of TPUE. Results show that the polyurethane elastomers present higher molecular weight (Mn>8×10⁴), and have relatively lower glass transition temperature of soft segment (T, < -56 C) which indicate that they have good low temperature mechanical properties. The elastomers exhibit optimum mechanical properties (σ >18 MPa and ε>500%) when the hard segment concentration is controlled between 50% and 60%. When the TPUE is introduced into modified double base propellant, the mechanical properties at low temperature are remarkably improved and the tensile strength at high temperature are slightly lowered.