Enthalpy of Formation of p(BAMO)-b-GAP and Energetic Characteristics of Solid Propellants Based on the Copolymer

The block copolymer of 3,3’-bis(azidomethy) oxetane and glycidyl azide polymer (p(BAMO)-b-GAP) is an ideal energetic binder for solid propellants. In this work, the enthalpy of formation of p(BAMO)-b-GAP was first investigated by the heat of combustion experimental method and group additivity method. Meanwhile, the energetic characteristics of solid propellants based on the copolymer were systematically calculated. The results proved that the Δ_fH of p(BAMO)-b-GAP could be estimated accurately by two methods and the positive Δ_fH values were obtained. Dual-oxidant formulas were designed in which AP was replaced gradually by some chlorine-free high-energy materials. The calculation results showed when AP was gradually replaced by RDX or HMX, the energy level of propellants based on p(BAMO)-b-GAP was improved first but then decreased with AP content further decreased, indicating there was an optimum ratio between AP and its alternative. However, when AP was replaced by CL-20 or ADN, the values of I_sp were improved steadily. When less than 40 % AP was replaced, the contribution to the energy level of propellant by RDX or HMX was even more than that by CL-20.