Enhancing flame retardancy of flexible polyurethane foams through one-step coassembled nanocoatings

Scalable and durable flame retardant nanocoatings were prepared through a fast, one-step coassembly process and applied to flexible polyurethane (PU) foams. The coated PU foams exhibited excellent performance, remaining highly flame retardant even after 1000 compression test cycles. The effect of the ratio of montmorillonite (MMT) to polyacrylic acid (PAA) on flame retardancy and compressive characteristics was systematically explored. The samples coated with only MMT and ammonium dihydrogen phosphate (ADP) displayed the weakest resilience and the greatest weight loss in the cyclic compression test. However, a higher content of MMT in the coatings could enhance the flame retardancy and thermal stability of the coated PU foams. Although PAA might not directly contribute to the flame retardancy of PU foams, it plays a key role in maintaining the robustness and resilience of the coating layer during multiple cycles of compression. Our research offers an effective method for producing scalable, durable, and robust flame retardant nanocoatings through a one-step process, suitable for PU foams and potentially many other substrates.