Influence of nano-boron nitride on anti-aging property of waterborne fire-resistive coatings

The influence of nano-boron nitride (BN) with a multilayered structure on the anti-aging property of fire-resistive coatings was studied. After accelerated weathering for 20 days, the thermal stabilities and fire protection of the coating without nano-BN were significantly decreased, but the coating modified by nano-BN still maintained excellent intumescent effect and fire protection. The results indicated that nano-BN could improve the anti-aging property of the coatings remarkably. FTIR and XPS characterizations suggested that nano-BN with a multilayered structure could prevent the migration behavior of the hydrophilic fire-retardant additives and keep the fixed ratio of those additives in the coating. TGA results demonstrated that nano-BN could effectively enhance the thermal stabilities of the aged coatings and improve the anti-oxidation property of the char layers formed by the coatings. XRD and EDS results proved that the anti-oxidation of the aged coatings under high temperature could be enhanced effectively after adding nano-BN. SEM observations illustrated that nano-BN addition was beneficial to the improvement of the foam structure of the aged coating.