Research Progress on Boron-Modified Phenolic Resin Ablation-Resistant Composites

Boron-modified phenolic resin composites are critical aerospace thermal protection materials due to their ability to form boron-containing ceramic layers during ablation, which provides exceptional ablation resistance. This article systematically reviews recent research progress on boron-modified phenolic resin ablation-resistant composites from two primary design perspectives. Firstly, from the perspective of the resin matrix level, strategies for chemically bonding boron elements to phenolic resins are summarized. Using boron-containing compounds like boric acid or phenylboronic acid introduces high-bond-energy B-O bonds, fundamentally enhancing the resin's thermal stability and performance under extreme conditions. Building on this, introducing boron-containing ceramic precursors into phenolic resins can further optimize their ablation resistance and high-temperature performance. Secondly, at the composite level, the incorporation of single- or multiphase boron-containing ceramic fillers is reviewed. These fillers enable the in situ development of high-viscosity molten ceramic layers during ablation, exhibiting exceptional thermal stability and ablation resistance. Finally, the fundamental mechanisms governing the thermal resistance and enhanced ablation achieved through both chemical modification and the introduction of ceramic reinforcing phases are summarized.