Comparative Study of High-Temperature Polymer Composites Under Varying Simulated Re-Entry Conditions

This study investigates the thermal and ablative behavior of four Bulk Molding Compound (BMC) composites, including a benchmark phenolic-formaldehyde (PF), trismaleimide (TMI), benzoxazine (BZ), phthalonitrile (PN), and silica glass fibers (GF). Thermogravimetric analysis (TGA) and dynamic-mechanical analysis (DMA) revealed that PN indicates the highest thermal stability, char yield (73%), and glass transition temperature (Tg ) of 434 °C. PF retained 61% char, while TMI and BZ retained 52% and 47%, respectively. A sharp mass loss was observed for TMI, while BZ decomposed at a lower temperature, indicating limitations under high thermal loads. Furthermore, aerothermal testing at 500, 1000, and 1500 W/cm 2 revealed that all composites outperformed the benchmark. The GF/PN composite showed the lowest erosion rate (ER), though it had a high mass ablation rate (MAR) and poor insulation properties. In contrast, the GF/BZ composite exhibited the lowest MAR and highest front-face temperatures, suggesting promising potential for TPS applications. Both TMI and BZ resins demonstrate favorable ablation performance despite their lower char yields. These findings highlight especially the potential of GF/PN and GF/BZ composites as alternatives to traditional PF resins for TPS applications.