Ablation Mechanisms in Plastics With Inorganic Reinforcement

Experimental and theoretical studies are described which clarify the nature and importance of the chemical and physical processes tha t occur in the ablation of these materials. Products and amount of gas from resin pyrolysis are determined from tube furnace tests, the rate of the process is inferred, heat effects are measured by calorimetric methods, and the rate of inorganic reaction between carbon and glass is measured in an induction heated furnace. The heterogeneous silicacarbon reaction is coupled to aerodynamic conditions and this results in a cutoff temperature for such chemical reaction. From an examination of re-entry specimens and order of magnitude calculations of possible carbon-consuming processes a realistic overall picture of the ablation is emerging. Resin decomposition during ablation and further reaction of the high moJecular weight species are treated analytically.