Review of novel energetic polymers and binders – high energy propellant ingredients for the new space race

Abstract

Current solid rocket propellant formulations still employ traditional ingredients utilized since the 1960s, such as hydroxyl terminated polybutadiene (HTPB). Recent advances in energetic polymer see many binders capable of providing higher specific impulse and burn rates over HTPB. As shown by calculations, even slight increases in specific impulse can drastically increase the maximum payload of a launch system. Therefore, replacing HTPB with energetic binders could provide heavy space missions the needed extra boost. Energetic binders could also be paired with chlorine-free energetic oxidizers to synergistically provide a specific impulse exceedingly higher than the current formulation while reducing pollution. A comprehensive evaluation of the synthesis, mechanical properties, and performance of various trending and overlooked energetic polymers is described. Several outstanding candidates show promising properties to replace HTPB.

Thermal and Mechanical Properties of Triazole Cross‐Linked Glycidyl Azide (GAP) and Azido Polycarbonate Networks

“…The cured network resulting from the reaction between azido polymers and dialkynes is a cross‐linked polymeric network with bis‐1,2,3‐triazole bridging units distributed in a random fashion along the chains. Resins cured in this fashion can show improved mechanical properties and burning characteristics compared to similar polyurethane‐cured networks [7, 8], but at the cost of reduced elasticity and increased glass‐transition temperatures (T g ). The properties of triazole‐bridged networks can be assumed to vary with the concentration of bridging units, with the length of the pre‐polymer chains, and also with the nature of the dialkynes used as bridging units.…”

Reactive & Efficient: Organic Azides as Cross-Linkers in Material Sciences

“…Benefits of azido crosslinking include better stability and enhanced burn rate of the crosslinked polymers. For more examples of azido polymers as energetic binders the reader is referred to the literature [26,31,32].…”

Preparation of Azido Polycarbonates via Bulk Polymerization of Halogenated Diols

“…Different energetic polymers have been developed to fill this need but only a small number of them have been produced in large quantities, namely glycidyl azide and glycidyl nitrate polymers, GAP and polyGLYN [1,2]. These slow developments have been due in part to the low commercial availability of energetic polymers, and to the fact that they often show inferior mechanical and thermal properties when compared to their inert counterparts such as hydroxyl-terminated polybutadiene (HTPB) [3].…”