Exploring composites based on PPO blend as ablative thermal protection systems – Part I: The role of layered fillers

An ablative Thermal Protection System (TPS) is a sacrificial shield able to insulate aerospace vehicles during atmospheric re-entry. In this paper, PPO-based composites were investigated in view of their potential exploitation as innovative ablative TPS. Their ability to degrade undergoing endothermic reactions and yielding a char layer was evaluated by means of thermal analyses and cone calorimeter tests. This first part discusses composites containing layered particles, in particular a cationically modified clay, a hydrotalcite and a sepiolite. Among them, sepiolite-added PPO composites showed the most promising behavior. In Part II spherical oxide and non-oxide fillers in the same matrix are studied.