Investigation on mechanical and thermal properties of HTPE/PCL propellant for wide temperature range use

Hydroxyl-terminated polyether (HTPE) propellant and HTPE/Poly(ε-caprolactone) (PCL) propellant were compared to explore the effects of introducing PCL to HTPE propellant on the mechanical and thermal properties at the wide temperature range of − 50 °C to 70 °C. The energetic properties of HTPE and HTPE/PCL propellants were also evaluated, the ideal specific impulse and density of HTPE/PCL propellant were found to be slightly enhanced comparing with those of HTPE propellant. The tensile mechanical properties results revealed that the introduction of PCL could improve the maximum tensile strength (σ_m) of HTPE/PCL propellant at the wide temperature range of − 50 °C to 70 °C, its σ_m increased from 0.38 to 0.75 MPa at 20 °C, 0.25 to 0.48 MPa at 70 °C and 4.01 to 4.77 MPa at − 50 °C separately comparing with those of HTPE propellant. The thermal decomposition behavior at 0.1 MPa showed that the introduction of PCL could promote RDX and AP in HTPE/PCL propellant to decompose. Bu-NENA was hardly to evaporate from HTPE/PCL propellant at higher pressure, which was beneficial to its thermal decomposition. The introduction of PCL could be more effective to inhibit the evaporation of Bu-NENA from HTPE/PCL propellant at 0.1 MPa, the activation energy of evaporation of HTPE and HTPE/PCL propellants was 53.66 kJ mol⁻¹ and 77.90 kJ mol⁻¹, respectively.