High Volumetric Specific Impulse Composite Propellant Based on Terminally Functionalized Block Copolymers of Polybutadiene and ϵ‐Caprolactone

Abstract

AbstractFor enhanced range, higher payload capacities and for miniaturized propulsion systems, today's strategic and tactical weapon system designers demand for higher density and specific impulse of the propellant. In order to enhance the density impulse of HTPB/DOA/RDX/AP/Al based composite propellant, studies have been carried to replace conventional HTPB/DOA binder system with hydroxyl terminated block copolymer of polybutadiene and ϵ‐caprolactone with NG as plasticizer. Total eight numbers of compositions were formulated with varying content of RDX. Both binder systems were compared in propellant compositions by evaluating various physical, thermal and ballistic properties. Various rocket performance parameters of each formulation were theoretically predicted by NASA CEC‐71 program and burning rate was measured in pressure ranges of 3‐7 and 7‐11 MPa by the acoustic emission technique. In addition, density, viscosity build up, calorimetric values, thermal decomposition and sensitivity parameters of each composition were also assessed and compared. In an outcome, it was concluded that HTBCP25/NG based propellant compositions enhance the density by 4.4–5 % and calorimetric values by 12–15 % as compared to HTPB/DOA based compositions. Strand burning rate data show enhancement of burning rate by 40–70 % at 7 MPa pressure in HTBCP25/NG based compositions. Impact and friction sensitivity data also revealed their utility in propellant compositions for future applications.