Novel eco-friendly bio-nano flame retardant via the electrostatic-driven hybridization of natural halloysite nanotubes and phytic acid for superior fire safety of epoxy composites

Driven by increasingly stringent safety regulations and enhanced fire hazards awareness, rationally designing a highly flame-retardant and eco-friendly polymer composites has become critically significant, but remains challenging. Herein, to endow epoxy resin (EP) composites with exceptional fire safety while maintaining its desirable performances, a novel bio-nano flame retardant GPP@HNTs was successfully prepared via the electrostatic-driven hybridization of two natural-available green materials, halloysite nanotubes (HNTs) and phytic acid (PA). It was found that the GPP@HNTs can uniformly disperse in EP matrix due to its strong interfacial interaction with EP. In compassion with EP, the flame retardancy of GPP@HNTs/EP composites was effectively enhanced, reaching UL-94 V-0 rating and exhibiting a 42.55 % increase of LOI value, 32.76 % decrease in peak heat release rate (PHRR), 25.92 % reduction in total heat release (THR). Furthermore, the GPP@HNTs/EP composites also present excellent thermal stability and mechanical properties. Such a facile yet efficient hybridization design of bio-nano flame retardant paves the way for wide practical applications of the flame-retardant and mechanically robust EP composites in various industrial fields.