Few materials can match the performance of cellulose and clay: They're readily available, nontoxic, and sustainable. Researchers from Texas A&M University leveraged the characteristics of these natural substances to invent a renewable flame-retardant coating.
The new coating offers a whole new level of fire protection for polyurethane foam and other highly flammable materials. Furthermore, it's made from some of the cheapest, easily acquired, and safest substances on the planet.
Dr. Jaime Grunlan, a professor of mechanical engineering at Texas A&M, led the development of the fire-proof coating. The paper, which detailed their findings, was featured on the cover of the science journal Advanced Materials Interfaces.
According to Grulan and his team, they're refining the fireproof coating for widescale implementation in the future. He expects the finalized product to keep insulation, textiles, and upholstered furniture from going up in flames and toxic smoke.
Products made from polyurethane foam stand to benefit the most from the new coating. The polymer-based material is exceptionally vulnerable to fire, but due to its prevalence in furniture and other products, treating all instances of foam with the flame-retardant coating is an expensive alternative. (Related: New study finds that toxic chemicals found in nail polish enter women’s bodies just hours after application.)
Cellulose, clay, and water make up this new fireproof material
The Texas-based researchers teamed up with their Swedish counterparts at KTH Royal Institute of Technology. The KTH team lent their expertise on nano-sized cellulose fibers to Grunlan, who used the information to complete his team's water-based coating.
Cellulose appears in wood and a variety of marine animals. Likewise, clay is one of the typical components of rock and soil formations. The two materials provide mechanical support to the structures that contain them.
“The uniqueness in this current study lies in the use of two naturally occurring nanomaterials, clay nanoplatelets and cellulose nanofibrils,” explained Grunlan. “To the best of our knowledge, these ingredients have never been used to make a heat shielding or flame-retardant coating as a multilayer thin film deposited from water.”
The new fireproof material exhibits many advantages over earlier counterparts. It generates an oxygen barrier that prevents flame and heat from reaching plastic film and other flammable items. The coating also performs better than other flame-retardant treatments at a much lower price. Last and not least, it does not have cancer-causing ingredients, making it safe for use around humans.
Polyurethane foam coated in the flame-retardant coating can shrug off intense heat
For the study, Grunlan and his team treated polyurethane foam samples with the flame-retardant substance, leaving other foam samples uncovered for control. They then took a butane torch to the samples to see if their coating worked as designed.
Unsurprisingly, unprotected polyurethane foam melted into goo the moment it came into contact with the butane torch. In contrast, the foam coated with the cellulose-clay material survived extended periods of exposure to the hot flame.
While the surface of the fireproof coating displayed fire damage, it did not break. Beneath it, the polyurethane foam remained unscathed despite the intense heat of the butane-fueled flame washing over its sturdy coat.
“The nanobrick wall structure of the coating reduces the temperature experienced by the underlying foam, which delays combustion,” he added. “This coating also serves to promote insulating char formation and reduces the release of fumes that feed a fire.”
Thanks to the successful conclusion of the research stage, the Texas A&M team are now modifying their flame retardant material for possible adoption and production by an industrial partner.
Sources include:
Please contact us for more information.