A bio-inspired self-assembly strategy toward mechanically robust and flame retardant nanocomposites with ultra-sensitive and super-durable fire warning

Abstract Poly(vinyl alcohol) (PVA) is widely applied in intelligence devices and energy storage, while its high flammability still challenges its development regarding the fire safety when employing in the regional heat accumulation circumstance. Herein, lamellar graphene oxide (GO) and bio-extracted phytic acid (PA) were introduced into PVA to fabricate a homogeneous PGP composite with excellent mechanical performance, flame retardancy and fire warning capacity through an eco-friendly water evaporation-induced self-assembly method. Via generating multiple interactions among PVA, GO and PA, the optimized cross-linked structure like hierarchical nacre was formed in PGP and presented simultaneously enhanced tensile strength and toughness than pure PVA. Owing to barrier effect of GO and free radical trapping and char catalyzing ability of PA, PGP composites showed excellent flame retardancy as the pHRR and THR decreased 88.6 and 66.5% compared to the pure PVA, and UL-94 level and LOI reached to V-0 rating and 36%, respectively. Moreover, the composite could maintain the structure integrity even after a longtime flame attack, displaying continuous warning ability over 2400 s. A fast dehydration and graphization process of the PGP composites allowed a rapid warning response within 2 s under fire. A better thermal accumulation endowed by GO lowered the response temperature to 150 ℃ which was sensitive to overheating. Besides, applying the PGP precursor solution as wood and cotton fabric coating could also improve the flame-retardant performance and endowed the fire warning capacity. Therefore, the composite fabricated in this work showed a great potential application in fire protection and warning.