文摘
A novel nanocoating, composed of montmorillonite (MMT) nanosheets and 尾-FeOOH nanorods, was deposited on the surface of flexible polyurethane (FPU) foams through a layer-by-layer assembly technique to reduce its flamability. The coating growth was performed by alternately immersing FPU foams into polyethylenimine (PEI) solution, MMT-alginate suspension, and 尾-FeOOH dispersion. Structural and morphological characterization indicated that MMT nanosheets and 尾-FeOOH nanorods were distributed homogeneously on the surface of the matrix and formed a sandwichlike topology. The coated FPU foams showed the lower peak heat release rate (PHRR), compared to the counterparts fabricated by introduction of MMT nanosheets or 尾-FeOOH nanorods alone. Furthermore, the concentration of volatile products released from the coated FPU foams was reduced remarkably, indicating that the binary components had tremendous advantages in reducing the flamability of the material. These significant improvements in flame retardancy and toxic gas suppression could be attributed to the following: the MMT-based layers and the network formed by 尾-FeOOH nanorods exhibited a 鈥渓abyrinth effect鈥?to retard the permeation of heat, oxygen, and mass between the flame and underlying FPU matrix.