Nanosized bimetal-organic frameworks as robust coating for multi-functional flexible polyurethane foam: Rapid oil-absorption and excellent fire safety

Finding a facile strategy to fabricate robust coating on the skeletons is crucial to improve the performance of flexible polyurethane foam (FPUF). Nanosized bimetal-organic frameworks (MOFs-NH2) and (3Mercaptopropyl) trimethoxysilane (MTS) were used to modify FPUF in this work to enhance its oil absorbency and flame retardancy. MTS used as adhesive to provide strong interaction between MOFs-NH2 and FPUF. FPUF@ MOFs-NH2 showed superhydrophobicity even after compressive stain-stress test for 1000 cycles. Meanwhile, FPUF@MOFs-NH2 sponges not only had higher oil absorbency than previous FPUF-based adsorbents, but also superior reusability. After 400 cycles adsorption-squeezing test, FPUF@MOFs-NH2 still kept high absorbency. Fire safety of the sponge was significantly improved after coating MTS and MOFs-NH2: fire spread and heat release rate were significantly suppressed. The possible oil absorbency and flame retardancy mechanisms were proposed based on the analysis results. This work broadens the application field of MOFs and paves a new direction to prepare functional FPUF composites with excellent performance.