Highly transparent and flame-retardant cellulose films composited by amorphous ammonium polyphosphate with high...

A novel, highly transparent and flame-retardant cellulose composite film was fabricated via the method of dissolution-regeneration and solvent exchange. High degree of polymerization ammonium polyphosphate (HAPP) was dissolved in hot water to prepare the HAPP aqueous solution. Then water in the regenerated cellulose hydrogel was replaced by the obtained HAPP aqueous solution through a solvent exchange method to obtain the flame-retardant cellulose composite films. When the concentration of HAPP was 3 wt%, the limiting oxygen index (LOI) of the cellulose composite films reached 46, and the UL-94 was V-0 rating. No APP crystal appeared in the flame-retardant cellulose composite films, and the light transmittance at 600 nm remained over 90 %, displaying good transparency with no difference compared to the pure cellulose film. Our study provides a facile and efficient method to produce highly transparent and flame-retardant cellulose composite film that holds great potential to be applied in fields such as electronic packaging and optoelectronic devices.