Tri-source integrated adenosine triphosphate loaded BN in synergy with Cu-MOF to improve the fire safety of epoxy resin

Abstract

The volume expansion of the char layer during combustion can effectively isolate the external flame and heat. However, the contribution of conventional flame retardants to the volume increase is largely negligible. Adenosine triphosphate (ATP), as a bio-based macromolecule, contains both acidsource, carbon source and gas source groups in its structure, which determines the ability of these groups to synergistically promote the formation of swollen residual carbon at high temperatures, resulting in a good flame retardant effect. Here, a novel and highly efficient organic–inorganic composite flame retardant was achieved by coupling ATP with BN using polydopamine (PDA) as a medium and anchoring Cu-MOF nanoparticles uniformly on its surface. Among them, the high barrier of BN imparted the EP resin and residual carbon excellent heat shielding properties, the presence of ATP facilitated the formation of expanded carbon slag. Besides, the metal ions in Cu-MOF promote the conversion of more cracking products to residual carbon, while the microporous structure of MOF has an appreciable adsorption effect on the flue gas. The results showed that compared to EP, the THR and PHRR for BN/PATP@Cu-MOF/EP decreased by 32.0% and 41.3%, separately. Moreover, the PSRP, TSP, PCOPR and PCO2PR values of BN/PATP@Cu-MOF/EP were visibly lower than those of other specimens, decreasing to 0.226 m2/s, 20.43 m2/s, 0.081% and 0.73%, accordingly, justifying its most optimal fume suppression effect. According to the condensed phase and gas phase flame retardant principle, the synergism of BN, ATP and Cu-MOF leading to the construction of an expanded coal network having greater strength and barrier properties, which is the key to reduce heat release and smoke generation. This study opens the door to new swellable flame retardants and provides a new effective way for flame retardant modification of polymers.