Mechanical properties of HTPE/Bu-NENA binder and the kinetics of Bu-NENA evaporation

The correlation between the mechanical properties of hydroxyl-terminated polyether (HTPE)/N-butyl-N-(2-nitroxyethyl)nitramine (Bu-NENA) binders with different plasticization ratios (pl/po), varied from 0.9 to 1.5, have been studied. The very early stage of evaporation of Bu-NENA from the HTPE/Bu-NENA binder, with a pl/po ratio of 1.2, has been investigated. The results revealed that the pl/po ratio has strong influences on the mechanical properties. When the pl/po ratio was 1.2, the mechanical properties of the HTPE/Bu-NENA binder were satisfactory, the maximum tensile strength and the elongation at break being 2.39 MPa and 93.27%, respectively. The evaporation rate constant of Bu-NENA from HTPE/Bu-NENA binder with a pl/po ratio of 1.2 increased from 0.31·10^-5 to 2.32·10^-5 s^-1 as the temperature was increased from 50 to 90 °C. The value of the activation energy of evaporation was 51.47 kJ/mol and its pre-exponential factor was 6.14·10² s^-1.