Solid propellant with embedded additively manufactured reactive components

The geometric flexibility of additive manufacturing (AM) has been touted in the energetic material space, but little has been done to incorporate reactive materials that have been 3D printed into complex geometries inside of solid propellants. Further investigation of the intersection of additive manufacturing with new, reactive printable materials is needed to explore the potential of AM processes to tailor and optimize propellant performance. In this work, propellant strands consisting of ammonium perchlorate/hydroxyl-terminated polybutadiene (AP/HTPB) were embedded with either an inert copper or additively manufactured aluminum-fluorocarbon reactive “wire”. For this work the propellant was cast traditionally and not printed. Future work could include printing both the reactive and the propellant materials. The additively manufactured reactive wires were printed into simple cylindrical and branching geometries. Strands were tested with an X-ray imaging system that allowed for the observation and characterization of internal burning surfaces. Our results demonstrate a new way to tailor the profile of a burning propellant surface by alteration with printable, embedded reactive materials (or “reactive wires”).