Green and Facile Fabrication of Magnesium‐Aluminum Hydrotalcite for Synergistic Flame Retardancy, Smoke Suppression, and Thermal Insulation in Epoxy Resina

ABSTRACT A dual‐surfactant modification strategy was developed to synergistically enhance the flame retardancy and smoke suppression of epoxy resin (EP) by co‐modifying Mg‐Al layered double hydroxide (LDH) with sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS). This dual‐surfactant approach is novel as it integrates two distinct functionalities—linear alkyl chain compatibility provided by SDS and aromatic sulfonate‐induced charring contributed by SDBS—resulting in a synergistic improvement in LDH dispersion, interfacial bonding, and catalytic char formation, thereby achieving superior fire safety performance in EP composites. The modified SDS + SDBS‐LDH was synthesized via a green ion‐exchange route and uniformly dispersed in EP at a loading of 5 wt%. In cone calorimeter tests, total heat release and total smoke production decreased by 33.3% and 22.9%, respectively, while CO and CO 2 release rates dropped by 75.8% and 48.7% compared with pure EP. When applied as a coating, EP/5SDS + SDBS‐LDH reduced the back‐surface temperature of wood by 76.1%, demonstrating excellent thermal insulation and practical potential. This work provides a scalable and eco‐friendly strategy for designing high‐performance, flame‐retardant epoxy composites through synergistic dual‐surfactant modification of LDH.