Two birds with one stone: Construction of bifunctional-POSS hybridized boron-silicon ceramicized phenolic composites and its ablation behavior

•Alkalic heptaphenyltrisilanol sodium salt polyhedral oligomeric silsesquioxane was utilized as catalyst and silicon source to obtain novel boron-silicon hybrid phenolic resin (BPOSSPR).•BPOSSPR composites possesses excellent thermal, mechanical, insulation, and ablation resistance properties.•The relationships of the oxidation and ablation behaviors for the thermal protection BPOSSPR under extreme environments were illustrated.•The mechanisms for thermal responses, oxidation, ceramic formation, and ablation of these thermal protection materials were provided.