Parents who worry about toxic chemicals in nonflammable children’s clothing can soon breathe a sigh of relief. Using a technology that protects skyscrapers from fire, Texas A&M University scientist have developed a fire-resistant fabric composed of renewable ingredients such as garden-variety clay and chitosan, a natural compound extracted from shrimp and lobster shells. When heat is applied to the material, the coating bubbles out, creating a protective layer of foam that keeps the fabric from igniting. The first-of-its-kind polymer treatment could find applications in children’s pajamas, terry-cloth bathrobes, and car seats, according to Jaime C. Grunlan, the associate professor of mechanical engineering heading the research. The water-based ingredients are less toxic than the so-called ‘halogenated’ or ‘brominated’ flame-retardants typically used, he says, not to mention more environmentally friendly.
The breakthrough occurred five years ago when Grunlan and his team realized the coating on a separate food-packaging project had flame-retarding properties. The researchers mailed a piece of treated foam to the National Institute of Standards and Technology for a standard fire test. “NIST couldn’t even tell there was a treatment on the foam,” Grunlan tells The American Statesman. “So they were excited and shocked about the improvement in the foam’s fire behavior.” The results led to the group’s first funded project, which has allowed them to continue their research with an eye on commercialization.
Because the layers are so thin, the polymers seep into the fabric to coat each individual fiber.
Unlike typical flame-retardants, which settle on top of fibers like a shield but doesn’t prevent them from burning and turning black, the new material uses alternating films only a tenth of a micron thick, or one-thousandth the width of a human hair. Because the layers are so thin, the polymer liquid seeps into the fabric to coat each individual fiber. When the new coating is exposed to a flame, it expands slightly to stop it from igniting and burning the fabric, which remains pristine except for the small area when the fabric is in direct contact with the fire.
Plus, Grunlan and his team are able to control the thickness of the coating down to the nanometer, adding a mere 1 to 2 percent to the fabric’s weight. The coating doesn’t effect the fabric’s color, texture, or strength, either, while most anti-flammables on the market today degrade the material and cause it to tear.
The next step is making the technology commercially viable while honing the recipe to improve its efficacy and feel. Grunlan says he isn’t interested in starting his own company but he’d like to see his work become the standard anti-flammable treatment for fabric, foam, and even wood. “I don’t know if this is realistic,” he says. “But it all starts with an idea.”