A flame retardant poly vinyl alcohol/graphene oxide/phytic acid composite for a quick response and ultra-long fire alarm

Abstract

Using sustainable bio-derivatives to fabricate mechanically robust, flame retardant composites with an ultra-sensitive and continuous fire warning capability remains an attractive theme in the fire prevention field. However, most researchers could hardly develop a composite with a short fire alarm response time at low temperature, continuous ultra-long warning, and high warning sensitivity under local heating conditions. Herein, lamellar graphene oxide (GO) and bio-extracted phytic acid (PA) were introduced into PVA to fabricate a homogeneous PGP composite with the above-mentioned performance 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 the 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 the UL-94 level and LOI reached the V-0 rating and 36%, respectively. Moreover, the composite could maintain structural integrity even after a long-duration flame attack, displaying continuous warning ability over 2400 s. A fast dehydration and graphitization process of the PGP composites allowed a rapid warning response within 2 s during a fire. A better thermal accumulation endowed by GO lowered the response temperature to 150 °C which was sensitive to overheating. Besides, based on PGP performance, it was used as a fireproof coating to apply on wood and cotton fabrics and presented excellent flame-retardant fire warning capability. Therefore, the composite fabricated in this work showed great potential application in fire protection and warning.