Abstract
Azido hydroxy terminated polybutadiene (AHTPB) is a candidate energetic binder for composite propellants having the same properties of hydroxy terminated polybutadiene (HTPB) but has an advantage over HTPB concerning its energetic property due to presence of azide group. Thermochemical calculations were done with different AHTPB percentages and the reference HTPB to examine the effect of binder change on the specific impulse and the flame temperature which are from the important parameters for the propellant performance and gun barrel age. AHTPB prepolymer was prepared by two steps method in which hydroxy terminated polybutadiene (HTPB) is firstly saturated with bromine (Br2) at room temperature giving bromo hydroxy terminated polybutadiene (BHTPB). Secondly, the formed BHTPB undergo substitution reaction using sodium azide (NaN3) at 70ºC for 30 hours on batches giving AHTPB with density of 0.967 g/cm3 and viscosity of about 5000 cP. The prepolymer was successfully prepared with conversion of (15%) and characterized by using some techniques such as infrared spectroscopy, elemental analysis, water content measurements and milligram equivalent (OH).