Synergistic enhancement in mechanical and ballistic properties of HTPB based energetic polymer composites

Abstract

Influence of chain extender (CE) and bonding agent (BA) on the mechanical, interfacial and ballistic properties of AP/Al/HTPB composite is determined and compared. Results indicate a relationship between the two properties. The composite without the additives exhibited extremely poor mechanical properties whereas maximum tensile strength and ultimate elongation is achieved by introducing CE in the conventional composite. Better mechanical properties in this modified composite also contributed in improving the ballistic behaviour. SEM analysis of the condensed combustion residues obtained from the propellant burnt in open atmosphere reveals a considerable decrease in the agglomerate size in the modified composite. This effect is reflected as higher specific impulse in this composite, determined from thrust time profile obtained in static bed test. Pressure time profile for the modified composite manifests a stable and consistent burning at the tail end in tubular geometry as opposed to the conventional system that exhibits a susceptible and unstable tail-off.

Rocket Propellant Comparison: Conventional Planetary Mixing and Resonant Acoustic Mixing

“…While the SEM images are a small portion of the whole, the indications are that coverage, or wetting of the particulate filler was better for the RAM prepared propellant than that prepared by the conventional method. De-wetting of solid fill from the binder of a composite viscoelastic material such as composite rocket propellant is a well-known mode of failure [6][7][8]. Better adhesion of the solid fuel and oxidiser is directly linked to superior mechanical properties and in particular, strain capability.…”