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A novel B–Si–Zr hybridized ceramicizable resin(BSZ-PR) was fabricated by chemical reaction of boric acid, zirconium hydroxyl-containing polyhedral oligomeric silsesquioxane(Zr-POSS) and phenolic. The incorporation of boric acid and Zr-POSS improved the thermal stability of the resin effectively, and the residual carbon rate increased to 72.63% at 800 °C under nitrogen atmosphere. The flexural strength of carbon fiber/BSZ-PR and high silica fiber/BSZ-PR composites were increased by 25.7% and 175.5%, and linear ablation rates were reduced by 37% and 44.75%, respectively. It was discovered that the ceramic structures such as SiO 2 , ZrO 2 and SiC can be formed at high temperatures as well as under extreme ablative conditions from both BSZ-PR and its fiber-reinforced composites, which may be the key to the improved thermal, ablative properties. [ABSTRACT FROM AUTHOR]

The utilization of advanced propellants leads to unbearable temperature and pressure in propellent ramjet engines, paving the way for the enhancement of thermal insulation materials. High temperature vulcanized polydimethylsiloxane composites have been adopted due to the satisfactory ablation resistance at the expense of complicated industrial costs. For the purpose of simplifying the processes and enhancing the ablation resistance of polymer matrices, room temperature vulcanized hydroxyl-terminated polydimethylsiloxane (HPDMS) crosslinked with multi-ethoxy POSS (EOPS) coatings (EOPS@ HPDMS) were prepared through capping crosslink. Comparative analyses of different EOPS loadings of EOPS@HPDMS revealed the chemical bonding of EOPS ameliorated the effects about crosslinking properties, mechanical strengths, thermal performance and ablation resistance of HPDMS. This work could provide an optional method for developing advisable ablation resistance composites in aerospace applications. Image 1 [ABSTRACT FROM AUTHOR]