Hortelano, C., De la Fuente, J. L. 2019. New Developments in Composite Propellants Catalysis: From Nanoparticles to Metallo-Polyurethanes. Nanomaterials in Rocket Propulsion Systems, Micro & Nano Technologies, 363-388, DOI: 10.1016/B978-0-12-813908-0.00009-5
The use of different additives to modify the burning rate (BR) of composite solid propellants (CSPs) has been a topic of much study during decades within rocket motor technology. This perspective chapter initially describes the effects of the performance of ammonium perchlorate-based composite propellants by means of employing nanopowder transition metal oxides as BR catalysts in comparison with traditional microfillers, the most representative and active of which are iron(III) oxide and cupric oxide. In addition, titania represents a new generation of BR catalyst with great potential in this field. CSPs with microparticles as catalyst seem to be less stable due to oversensitivity to pressure variations, but the nanostructured propellants yield highly stable BRs over a broad pressure range. On the other hand, a brief review of surveys of recent progress on the synthesis, macrostructural characterization, and properties of metallo-polyurethanes, as well as their applications as advanced binders in the formulations of CSPs based on hydroxyl-terminated polybutadiene, is addressed. The incorporation of both metallic oxide nanoparticles and polymeric organocatalysts based on ferrocene in the formulations of these energetic materials could improve their ballistic and thermal combustion properties. The latter characterization was commonly done by thermal analytical techniques, such as thermogravimetry analysis and differential scanning calorimetry.