Flash Pyrolysis of Ammonium Perchlorate-Hydroxyl-Terminated-Polybutadiene Mixtures Including Selected Additives

W ORLDWIDE, ammonium perchlorate (AP, NH^CIC^) and hydroxylterminated-polybutadiene (HTPB) composite mixtures, usually also containing aluminum powder and ballistic modifiers, are the most frequently used formulations in solid rocket propellants. In terms of publications, AP has been the most extensively investigated solid oxidizer since its introduction into propellants, probably in the late 1940s by the Jet Propulsion Laboratory. A large number of publications appeared in 1950-1970, and, by comparison, a relatively lesser number have appeared since then. The impressive review by Jacobs and Whitehead was quite extensive in range and depth at the time of publication in 1969. The falloff in research interest after this time is reflected in the additional information reviewed 10-15 years later, but subsequent reviews of various aspects of decomposition, ignition, and of AP-composite propellants have appeared. A modest resurgence of new interest in AP-composite propellant decomposition and combustion is motivated in part by the availability of advanced methods of diagnostics, by new kinetics data and methods of modeling, and by intriguing plateau-burning behavior of some AP-HTPB formulations.' Despite the widespread use and long investigative history of AP-fuel mixtures, it still can be said that AP alone and AP-fuel composites remain among the most confounding materials in the research setting. From the point of view of chemistry, one reason is that the full range of formal oxidation states of nitrogen and chlorine can apparently become involved, for example, the formal oxidation state of Cl in C1O4 is +7, whereas that of HC1 is -1; N in NHj is -3, whereas that of N in NOj (Ref. 19) and HNO3 (Ref. 20) is +5. When all of the various combinations of