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Nanocoating to Ward Off Flames

Wednesday, January 30, 2013

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Flame-retardant research is heating up in Texas, where researchers report the development of an environmentally friendly nanocoating that can be used on fabrics and foams.

The development, capping five years of research by materials scientists at Texas A&M University, could provide a long-sought alternative to flame retardants that use toxic chemicals.

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Building insulation coated with the new nanocoating could help ward off flames.

The nanocoating consists of two water-soluble polymers—one positively charged and one negatively charged. The coating does not make the substrate 100 percent fireproof, but it “dramatically diminishes the ability of the object to burn,” the university reported.

Fire-Retardant Development

Department of Mechanical Engineering Professor Jaime Grunlan led the research, which has been funded by several companies as well as the National Institute of Standards & Technology.

The team says the coatings are based on renewable, water-soluble and dispersible substances found naturally in the environment.

When coated and exposed to high temperatures, foams such as those found in sofas, mattresses, airplane seat cushions, theater and auditorium seats, and building insulation produce a protective carbon foam coating, according to the university.

The carbon foam coating allows the objects to ward off flames.

Clay and Lobster Shells

Texas A&M officials did not return a request for more information. However, an earlier report on the research noted that the team used coatings featuring a combination of chitosan and clay as an alternative to brominated compounds currently used in flame-retardant materials.

Texas A&M

Post-doctoral research assistant Galina Laufer applies the flame-resistant polymer-coated material to an open flame. The material produces a protective carbon foam coating when exposed to high temperatures.

“On polyurethane foam, a coating of chitosan (a natural material extracted from shrimp and lobster shells) and clay is deposited to eliminate melt dripping during burning,” according to the university’s report.

“The nanocomposite mixture coats the interior walls of foam. The result is that when burned, the treated foam keeps its shape instead of puddling at high temperatures like untreated polyurethane foam does. This quality eliminates the ‘melt-dripping’ effect that further spreads fires.”

“It’s like we’re building a nano-brick wall within each cell of the foam,” Grunlan said.

Grunlan said he hoped the first application of the polymer nanocoating for commercial use will begin in January 2014.

However, inventing and building the machines capable of producing and applying the nanocoating on a commercial scale remain obstacles, the scientist said.