Thermal decomposition kinetics of PBAN-binder and composite solid rocket propellants

Thermogravimetric analysis at heating rates between 0.5 and 10 degrees C mi n(-1) has been used to study the decomposition kinetics of the PBAN binder and three propellants based on ammonium perchlorate (AP) with PBAN, HTPB, o r BAMO-AMMO binders. Thermal runaway was observed for the PBAN and HTPB pro pellants at heating rates faster than 4.5 and 3 degrees C min(-1), respecti vely. The multistep decomposition kinetics were analyzed by an advanced iso conversional method that showed that the effective activation varies with t he extent of decomposition of the studied systems. For PBAN the activation energy increases from 100 to 200 kJ mol(-1) throughout the polymer decompos ition. In propellants the major mass loss step primarily relates to AP deco mposition accompanied by some degradation of the polymer binder. For the PB AN and HTPB propellants this step shows respective increases in the activat ion energy from 60 to 180 kJ mol(-1) and from 100 to 230 kJ mol(-1). The ma jor decomposition step of the BAMO-AMMO propellant has a fairly constant ac tivation energy of 120 kJ mol(-1). (C) 1999 by The Combustion Institute.