Electrostatic incorporation strategy induced hierarchical 2D/2D nanostructure enabling fire-resistant and mechanic-robust epoxy composite for safe construction usage

Epoxy resins (EP) are extensively used across construction, electronics, and aerospace industries due to their exceptional mechanical strength and chemical stability. However, their inherent flammability and emission of toxic gases during combustion presents the significant safety concerns, particularly in building and construction fields that demand strict fire safety compliance. This study introduces a cutting-edge flame-retardant system, consisting of tannic acid-functionalized boron nitride (TBN) and chitosan-modified phosphorus-doped graphitic carbon nitride (CPCN) to form a hierarchical 2D/2D TBN@CPCN nanostructure. Incorporating 2.0 wt% TBN@CPCN into EP reduces the peak heat release rate (PHRR) by 44.8 %, decreases total smoke production (TSP) by 53.7 %, and lowers the peak CO yield by 43.3 %. Additionally, the tensile strength is increases by 20.4 %, reaching 68.4 MPa, while flexural strength improving to 95.6 MPa. The Analytic Hierarchy Process (AHP) is utilized to systematically evaluate fire safety parameters, including heat release, smoke toxicity, and mechanical performance, underscoring the superior capabilities of TBN@CPCN system. These advancements render the material highly suitable for modern infrastructure applications, where safety and durability are paramount. This work offers a promising pathway for developing high-performance, flame-retardant EP composites tailored for construction and building materials.