Environmentally Friendly, High-Performance Fire Retardant Made from Cellulose and Graphite

Abstract

Many materials and additives perform well as fire retardants and suppressants, but there is an ever-growing list of unfulfilled demands requiring new developments. This work explores the outstanding dispersant and adhesive performances of cellulose to create a new effective fire-retardant: exfoliated and reassembled graphite (ERG). This is a new 2D polyfunctional material formed by drying aqueous dispersions of graphite and cellulose on wood, canvas, and other lignocellulosic materials, thus producing adherent layers that reduce the damage caused by a flame to the substrates. Visual observation, thermal images and surface temperature measurements reveal fast heat transfer away from the flamed spots, suppressing flare formation. Pinewood coated with ERG underwent standard flame resistance tests in an accredited laboratory, reaching the highest possible class for combustible substrates. The fire-retardant performance of ERG derives from its thermal stability in air and from its ability to transfer heat to the environment, by conduction and radiation. This new material may thus lead a new class of flame-retardant coatings based on a hitherto unexplored mechanism for fire retardation and showing several technical advantages: the precursor dispersions are water-based, the raw materials used are commodities, and the production process can be performed on commonly used equipment with minimal waste.

Progress in Achieving Fire-Retarding Cellulose-Derived Nano/Micromaterial-Based Thin Films/Coatings and Aerogels: A Review

“…EG is an intumescent FR additive that forms a worm-like structure when burned and builds a thick barrier to hinder the transfer of flammable volatiles. Santos and co-workers prepared a flame-retardant coating composed of MCC and expandable graphite [92]. The cellulose showed excellent substrate properties for the graphite due to its outstanding adhesive properties.…”

Effect of Expandable Graphite Flakes on the Flame Resistance of Oak Wood

“…Oak is classified as very heavily treatable, and impregnation is therefore challenging; for example, Franke and Volkmer [18] treated oak wood with a new fire retardant based on in situ calcium oxalate deposition. Other authors used exfoliated and reassembled graphite on the wood surface [19], mixing wood particles with EG [20] and EG with an intumescent flame retardant in wood flour-polypropylene composites [15]. However, the application of EG to flame-retardant coatings for wood and other lignocellulosic materials is still not reported adequately, although some works on this issue have been published [6,21].…”

Synthesis of P-/N-Containing Bamboo-Activated Carbon toward Enhanced Thermal Stability and Flame Retardancy of Polylactic Acid

“…Multiple bio-materials such as lignin [ 14 , 15 ] and starch [ 13 , 16 ] have been grafted to the intumescent flame retardant system to improve flame retardancy. Additionally, carbon-based materials, such as graphite [ 17 , 18 , 19 , 20 ], graphene [ 21 , 22 , 23 ] and carbon nanotube [ 24 , 25 , 26 ] were usually considered outstanding options due to their unique structure (dense networking); nonetheless, the inferior dispersion in matrix and cost concerns significantly dampen the incentive for their commercial development.…”