Thermally induced fire early warning aerogel with efficient thermal isolation and flame‐retardant properties

Abstract

Due to the energy‐saving demands in chemical industries and building fields, thermal isolation materials (TIMs) are widely used. The general exploitation of combustible TIMs calls for timely fire alerts as well as flame‐retardant modifications. This work provides a novel paradigm to address the issues simultaneously by preparing a multifunctional aerogel via a facile and environmentally friendly freeze‐drying method. With the doping of ammonium polyphosphate and graphene oxide (GO), cellulose nanofiber‐based aerogel exhibits excellent thermal‐isolating as well as flame‐retardant properties. The composite aerogel displays flameless pyrolysis as well as increased residue char. A fire‐warning detector is designed to reliably monitor the early fire. Based on the flame‐induced electrical resistance transformation characteristic of GO, it endows the composite aerogel with an ultra‐fast fire‐response time of ~2.6 s and a durable alarm signal. The flame‐retardant and fire‐alarm mechanisms are concluded. Overall, these results suggest that this composite aerogel has an enticing prospect in chemical industries and high‐rise buildings, which may lay the foundation for designing multifunctional TIMs. The modified aerogel broadens its application territory by intrinsic fire‐alarm characteristics, which covers the deficiency of delaying reaction as well as restricted application scenarios in traditional fire detectors.

Recent Advances on Early-Stage Fire-Warning Systems: Mechanism, Performance, and Perspective

“…On the basis of the superiority of GO, varied early fire sensors based on different substrates are reported [60,[68][69][70][71][72][73][74][75][76][77][78][79]. Eco-friendly paper is one of the substrates.…”

Recent Advances in the Synthesis and Application of Three-Dimensional Graphene-Based Aerogels

“…Graphene aerogel, with characteristics of low density, high surface area and porosity, and good electrical and thermal conductivity, has attracted the attention of researchers and flourished in the recent decades [ 68 ]. They possesses potential application in diverse fields, such as sorption in environmental protection [ 26 , 69 ] electrode materials [ 70 , 71 ], electronic devices [ 72 ], flame-retardant and fire-warning materials [ 73 , 74 ], catalysis [ 75 ], energy storage [ 76 ], and microwave absorption [ 58 ]. Based on the adsorption, electrochemistry, mechanical, catalytic, and fire-warning properties of GAs, here we mainly summarize its application fields and classify it into five aspects (absorbent, anode material, mechanical device, fire-warning materia,l and catalyst) sequentially.…”

“…However, because of its unique porous network structure, aerogel inevitably encounters difficulties in reducing electrical resistance during being burned, which remains a challenge to fabricate sensitive fire-warning aerogels [ 106 , 107 ]. Yuan et al [ 73 ] creatively prepared the GO/ammonium polyphosphate/cellulose nanofiber composite aerogel with a fire-response time of 2.6 s through freeze-drying for the first time. The aerogel exhibits excellent thermal-isolating, flame-retardant, and timely fire-alarm properties.…”

Multifunctional MXene/Chitosan-Coated Cotton Fabric for Intelligent Fire Protection

“…In recent years, endowing the flammable materials with early fire-warning capability is a promising way to further enhance their fire safety. − When being burned, it can trigger the fire-warning system due to the rapid change of electrical resistance or voltage. Graphene oxide (GO) undergoes fast thermal reduction when encountering high temperature, showing a sharp decrease in resistance, which has become the most commonly used material for fire-warning sensors. − Tang’s group designed a series of GO-based fire-warning sensors, including GO/silicone coating, silane–GO papers, and clay/GO nanoribbon. − When confronted by high temperature, the sensors triggered the warning systems in several seconds, which were much shorter than those of the traditional fire alarm system (∼100 s) . In our previous work, we employed GO/cellulose nanocoating with sensitive fire-warning response and self-healing capability to improve the fire safety of polypropylene, polyurethane foam, and wood .…”