Burning Characteristics of Ammonium-Nitrate-Based Composite Propellants with a Hydroxyl-Terminated Polybutadiene/Polytetrahydrofuran Blend Binder

Abstract

Ammonium-nitrate-(AN-) based composite propellants prepared with a hydroxyl-terminated polybutadiene (HTPB)/polytetrahydrofuran (PTHF) blend binder have unique thermal decomposition characteristics. In this study, the burning characteristics of AN/HTPB/PTHF propellants are investigated. The specific impulse and adiabatic flame temperature of an AN-based propellant theoretically increases with an increase in the proportion of PTHF in the HTPB/PTHF blend. With an AN/HTPB propellant, a solid residue is left on the burning surface of the propellant, and the shape of this residue is similar to that of the propellant. On the other hand, an AN/HTPB/PTHF propellant does not leave a solid residue. The burning rates of the AN/HTPB/PTHF propellant are not markedly different from those of the AN/HTPB propellant because some of the liquefied HTPB/PTHF binder cover the burning surface and impede decomposition and combustion. The burning rates of an AN/HTPB/PTHF propellant with a burning catalyst are higher than those of an AN/HTPB propellant supplemented with a catalyst. The beneficial effect of the blend binder on the burning characteristics is clarified upon the addition of a catalyst. The catalyst suppresses the negative influence of the liquefied binder that covers the burning surface. Thus, HTPB/PTHF blend binders are useful in improving the performance of AN-based propellants.

Mechanical Characteristics and Thermal Decomposition Behavior of Polytetrahydrofuran Binder using Glycerol Propoxylate (Mn=260) as Crosslinking Agent

“…Polytetrahydrofuran (PTHF) is a raw material for rubber products; it is produced with various molecular weights on a commercial basis, and is inexpensive. Even though PTHF is not an energetic material, the specific impulse of PTHFbased propellants is theoretically superior to that of HTPBbased propellants, and furthermore, the burning rate of PTHF-based propellants is higher than that of HTPB-based propellants [9][10][11]. These results indicate that the PTHF binder is an effective and practical material for improving the performance of composite propellants.…”

Development of a composite solid propellant based upon phase stabilised ammonium nitrate

“…Furthermore, two prominent spike at the end of both profile indicates erosive burning, which is expected for long motors with BATES grain geometry propellant. These spikes may have been caused by inadequate ignition of the end surfaces which may originate from the inherent hard to ignite propellant properties and also tight spacing between both nozzle block assembly and bulkhead with propellant end surfaces [7]. Using these plots a specific impulse of 186s and a total impulse of 2194.5 N-s was calculated.…”

Combustion Properties of Composite Propellants Based on Two Kinds of Polyether Binders and Different Oxidizers

“…There are also many reports on the effect of blending binders on the combustion properties of propellants. Compared to ammonium nitrate/HTPB propellant, HTPB/polytetrahydrofuran blend theoretically enhances the specific impulse and adiabatic flame temperature and it does not leave solid residues on the combustion surface . The polytetrahydrofuran/glycerin mixture would be the useful binder system to improve the burning characteristics of the ammonium nitrate‐based propellants.…”