Expanded perlite/cork fillers applied to aerospace insulation materials

Abstract 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.

【摘要】 用于火箭发动机的隔热材料，如柔性热防护系统（Flexible Thermal Protections, FTPs）与刚性热防护系统（Rigid Thermal Protection, RTPs），可作为热屏障抵御固体推进剂燃烧产生的超高温环境。柔性热防护系统具备双重功能：一是延长刚性热防护系统的服役性能，二是缓解推进剂收缩效应。自20世纪70年代起，巴西航天计划中使用的柔性热防护系统配方含有石棉，然而石棉对人体健康存在危害性。在此背景下，研究人员以膨胀珍珠岩（Expanded Perlite, PExp）与软木粉（Cork Powder, CP）的混合物作为石棉的替代材料开展了相关研究。结果显示，该替代材料的密度降低了约21%，烧蚀性能提升了13%。由于该类柔性热防护系统的核心功能为缓解推进剂收缩，其较低的力学性能不会对实际应用造成不利影响。