Flame-Retardant and Alarm-Sensitive composite films by covalent modification of MWCNT with dopamine

• Multi-walled carbon nanotubes are amidated with bio-based material dopamine to prepare an efficient flame retardant. • a facile, environmental, economic strategy of vacuum filtration to fabricate GO/DCNT composite film. • Significant enhancement in flame retardancy and alarm-sensitive composite films. • The corresponding PHRR, THR, TSR, SPR, CO 2 , and CO were reduced remarkably. • The synergistic effect of gas phase flame retardant and condensed phase flame retardant between dopamine and MWCNTs. Carboxylic multi-walled carbon nanotubes (MWCNTs–COOH) and dopamine were combined to prepare DCNT hybrid nanostructure through amidation reaction, and as-obtained materials were further used as fire retardants introduced into graphene oxide (GO) to fabricate GO/DCNT composite films. The corresponding PHRR (up to 98.58%), THR (utmost to 20.29%), TSR (over 99.09%), SPR (above 67.66%) values were reduced remarkably. As a similar trend, significant decreases of 95.74% and 99.16% in release of CO 2 and CO were achieved. Flame retardant index (FRI) increased from 1.65 to 2.43, indicating the enhanced fire safety performance of GO. These positive results are attributed to the synergistic effect of gas phase flame retardant and condensed phase flame retardant between dopamine and MWCNTs. Raman spectra confirmed that the degree of graphitization of the carbon layer has been greatly improved, contributing to insulate the transfer of oxygen and heat. Meanwhile, GO/DCNT30 composite film exhibits ultra-fast intelligent fire alarm response capability (1 s). This work will provide a new method for the preparation of high-efficiency flame-retardant and ultra-fast intelligent fire alarm response materials.