The goal of this research is to characterize the mechanical properties of composite solid rocket propellants as they relate to two plasticizers: Dioctyl Adipate (DOA) and Isodecyl Pelargonate (IDP). Specifically, this project focused on the adhesive bond between a propellant and motor liner. Composite solid rocket propellants are composed of a polymer matrix, in this case, hydroxyl terminated polybutadiene (HTPB) rubber that is heavily loaded with solid additives. Oxidizing salts are replaced with sodium chloride salt of the same size to render the propellant inert. Tensile testing will follow ASTM E229 standards and both propellants will be hot-fired.