Flame-retardant effect of scalable all clay composite films

Flame retardants reduce fire risks from everyday materials that sustain a high standard of living. There is growing interest in applying surface treatments to localize flame-retardant chemistry at the surface of combustible material. This popular treatment method aims to maintain the desired bulk properties of materials and reduce the quantity of additives required. Owing to the excellent thermal stability, low cost and lightweight, clay nanomaterials are potential as environmentally friendly, lightweight, and practical flame-retardant materials. However, such potential may be restricted by the slow, tedious, energy-intensive, and unscalable fabrication process. Herein, large-area and flexible clay nanocomposite lamellar films with excellent thermal stability were fabricated by a simple and rapid doctor-blade coating method. The clay lamellar films can be applied to the surface of combustible materials to insulate them from heat and oxygen to provide a flame-retardant effect. By regulating the thickness of films and folding the films multiple times, the flame spread area decreased by 97.3 % and the total smoke production decreased by 74.7 % compared to the pure basswood board, showing excellent fire-retardancy. The large-area clay lamellar films made with simple processes and low-cost materials prove new strategies for efficient and environmentally friendly flame-retardant.