Abstract
In order to enhance the application properties of GAP in solid propellant, an energetic copolyurethane binder, (poly[3,3-bis(2,2,2-trifluoro-ethoxymethyl)oxetane] glycol-block-glycidylazide polymer (PBFMO-b-GAP) was developed. The PBFMO-b-GAP was prepared using poly[3,3-bis(2,2,2-trifluoro-ethoxymethyl)oxetane] glycol (PBFMO) which preparing from cationic polymerization and GAP as the raw materials, TDI as the coupling agent via a prepolymer process. The molecular structure of copolyurethane was confirmed by FT-IR, NMR, GPC. The impact sensitivity, mechanical properties and thermal behavior of PBFMO-b-GAP were studied by drop weight test, XPS, tensile test, SEM, DSC and TG/DTG respectively. The results proved that the introduction of fluoropolymer can evidently reduce the sensitivity of GAP based polyurethanes and enhance their mechanical behavior (the tensile strength up to 5.75MPa with a breaking elongation of 1660 %). Also, PBFMO-b-GAP exhibited an excellent resistance to thermal decomposition up to 200°C and good compatibility with Al and HMX. Cook-off test was used to investigate the reactive of copolyurethanes and Al, the results indicated that the copolyurethanes could react with Al efficiently and release significantly more heat. Therefore, the energetic copolyurethanes may serve as promising energetic binders for future propellant formulations.