Ammonium perchlorate

About: Ammonium perchlorate is a research topic. Over the lifetime, 2359 publications have been published within this topic receiving 33412 citations. The topic is also known as: AP.

Aging of HTPB/AP‐based composite solid propellants, depending on the NCO/OH and triol/diol ratios

Abstract: Aging behavior of hydroxyl-terminated polybutadiene/ammonium perchlorate (HTPB/AP)-based composite solid propellants was studied as a function of crosslink density, which is predominantly determined by the molar ratio of diisocyanate to total hydroxyl (NCO/OH ratio) and the molar ratio of triol to diol (triol/diol ratio). For this purpose, 16 propellant samples with different compositions were prepared by changing the NCO/OH ratio as 0.81, 0.82, 0.83, and 0.85 for each triol/diol ratio of 0.07, 0.09, 0.11, and 0.13, and subjected to an accelerated aging at 65°C. The changes in the mechanical properties were monitored throughout the aging period. In the initial part of the aging period, a sharp increase in stress, modulus, and hardness values and a sharp decrease in strain values were observed for all the propellants. At further stages of aging, only slight changes were observed in the mechanical properties. Concerning the aging criterion as reduction in the strain capability more than the half of the initial value, the propellants with respective NCO/OH-triol/diol ratios of 0.81–0.09, 0.85–0.09, 0.81–0.13, 0.83–0.13, and 0.85–0.13 can be considered to be aged with time. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 959–964, 2001

Impact Sensitivity of Propellants

Abstract: This paper reports an experimental study of the rapid deformation and ignition behaviour of a number of cast double-base propellants both at room temperature and at temperatures below the glass transition of those compositions that were elastomer modified. A range of techniques were used to obtain stress/strain data on the materials. A drop-weight machine with transparent anvils was used in conjunction with a high-speed camera to observe the deformation behaviour during impact. The aim was to gain understanding of the key parameters leading to the impact initiation of propellants. The only propellants that ignited violently in solid disc form at room temperature were the conventional compositions, the most sensitive being a composite modified propellant containing aluminium and ammonium perchlorate. All compositions were sensitized if they contained gas spaces. In addition, all the elastomer modified compositions were sensitized by cooling them below their glass transition ( ca .210K). The mechanisms leading to ‘hot spot’ formation and ignition of the propellants are discussed.