Synthesis and characterization of BAMO-THF azido-typed thermoplastic polyurethane elastomer

In order to study the effects of synthetic method and reaction conditions on the mechanical properties of azido-typed thermoplastic energetic binder, azido-typed thermoplastic polyurethane elastomer(ATPE)was synthesized by using melting-prepolymerization method with 3,3-bis(azidomethyl)oxetane-tetrahydrofuran(BAMO-THF)as soft segments, and isophorone diisocyanate(IPDI) & 1,4-butanediol(BDO) as hard segments. The ATPE structure was characterized by fourier transform infrared spectroscopy(FTIR). The optimized prepolymerization time was tested by using di-n-butylamine titration method. The impacts of cure parameter R and hard segment contents on the mechanical properties of ATPE were studied. ATPE glass transition temperature was measured by differential scanning calorimetry(DSC)and the percentage of hard segments dissolved in soft segments was calculated. The results show that ATPE has the typical features of azido-typed polyether-based polyurethane. The optimized prepolymerization time is 2 h. The maximal tensile strength of ATPE when R is 1.02 is approximately 4 MPa and that of ATPE with hard segment content 40% is 3.54 MPa. The percentage of hard segments dissolved in soft segments is lower than 10% and ATPE has the good property of microphase segregation when hard segment content exceeds 40%.