Study on the influence of hollow glass microspheres structure on the ablation performance of EPDM rubber

The increasing demand for lightweight and ablation-resistant materials in solid rocket engines has spurred the application of hollow glass microspheres (HGM) due to their low density and high thermal stability. In this study, the effects of different glass microspheres, including solid and hollow HS46 and HS38 microspheres, on the ablation and carbonization behavior of EPDM, PI/EPDM and PPTA/EPDM composites were evaluated using oxyacetylene tests and SEM. The results revealed that the addition of HGM decreased the ablation rates, with reductions of 13.2% for solid microspheres, 2.9% for HS46 compared with HGM-free composites. The presence of organic fibers further reduced ablation rates. Solid microspheres exhibited the most pronounced effect due to their superior thermal stability, whereas hollow microspheres with larger diameters tended to increase ablation rates as a result of fragmentation. Notably, the combined addition of HGM and fibers such as PI and PPTA reduced ablation rates by 50%. These findings provide valuable insights for designing advanced aerospace thermal insulation materials that are lightweight, thermally stable and exhibit enhanced ablation resistance.