Science and technology of polymeric ablative materials for thermal protection systems and propulsion devices: A review

Ablative materials are at the base of entire aerospace industry; these sacrificial materials are used to manage the heat shielding of propulsion devices (such as liquid and Solid Rocket Motors (SRMs)) or to protect vehicles and probes during the hypersonic flight through a planetary atmosphere. Accordingly they are also known as Thermal Protection System (TPS) materials. Some non-polymeric materials have been successfully used as ablatives; however, due to their versatility, Polymeric Ablatives (PAs) represent the widest family of sacrificial TPS materials. In fact, when compared to non-polymeric ablatives such as high melting point metals, inorganic polymers (or metal oxides or carbides), PAs have some intrinsic advantages such as: tunable density, lower cost, and higher heat shock resistance. This review covers all main topics related to the science and technology of ablative materials with current and potential applications in the aerospace industry. After a short, yet comprehensive, introduction on non-ablative materials, this review paper summarizes fifty years of research efforts on polymeric ablatives, starting from the state of the art solutions currently used as TPS, up to covering the most recent efforts for nanostructuring their formulations.