Rapid electrothermal response and excellent flame retardancy of ethylene-vinyl acetate electrothermal film

In this study, high electrical conductivity and flame retardant electrothermal ethylene-vinyl acetate (EVA) films were fabricated by using carbon nanotubes-wrapped ammonium polyphosphate (CAPP) and conductive carbon black (CCB). CAPP was used as a synergistic conductive filler and flame retardant to improve the electrical conductivity and fire safety of the electrothermal film at the same time. Besides, the heat release rate (HRR) and the total heat release (THR) of EVA-5 decreased about 81.5% and 57.3% compared with those of pure EVA film, respectively. Moreover, by incorporating a small amount of CAPP, EVA-5 can reach up to V-0 rating with an limiting oxygen index (LOI) value of 31%. EVA film fabricated by CCB and CAPP as conductive material exhibited almost 10 times increment on electrical conductivity than that of same content for CCB alone. And time vs temperature profiles of EVA-5 showed a stable trend over 3600 seconds without any offset at a given applied voltage of 15 V. Moreover, its excellent cycle heating performance indicated that the electrothermal film can be recycled, which meets the requirements of sustainable development. In a word, this novel strategy provides a simple and effective way to obtain a high conductive and fire safety electrothermal film.