Expanded perlite/cork fillers applied to aerospace insulation materials

Insulations for rocket motors such as Flexible Thermal Protections (FTPs) and Rigid Thermal Protection (RTPs) act as thermal barriers against the hyperthermal environment from the solid propellant combustion. FTPs present dual function: to extend RTPs performance, and to attenuate the propellant contraction. FTPs used in the Brazilian Space Program have asbestos in their composition since the 70´s; however, they are hazardous for human health. In this context, a mixture of Expanded Perlite (PExp) and Cork Powder (CP) was investigated as a replacement for asbestos. Results showed reduction about 21 % in density and an increase of 13 % in the ablative properties. The low mechanical properties not interfere in this type of FTP due to your function of attenuate the propellant contraction.