of Research of the National Institute of Standards and Technology

NIST RESEARCH SHOWS NANOCOMPOSITE CAN TAKE THE HEAT Remember the scene in “The Graduate” when a wouldbe mentor wraps his arm around young Benjamin and says, “I’ve got just one word for you . . . Are you listening? . . . Plastics!” If that film were being made in 1997, that one word might be nanocomposites. Nanocomposites are super plastics—compounds in which about 1 nm size particles of montmorillonite clay are dispersed throughout the polymers involved. NIST researchers have found that this new class of materials is tops in flame retardancy. Flammability in plastics is a major concern because fires started in the synthetic fabrics found in carpeting, upholstery, furniture or bedding often lead to property damage, injury or death. NIST’s experiments show that the heat release rate—the most important parameter for predicting fire hazard—is reduced 63 % in a nylon-6 clay-nanocomposite containing a clay content of only 5 %. According to one of the NIST researchers, the clay additive, unlike other fire retardant additives, does not degrade the overall material. Industry tests show the hybrid nylon-6 clay nanocomposite, compared to pure nylon-6 based plastic, has 40 % higher tensile strength (resistance to breakage), 68 % higher tensile modulus (ultimate level of resistance to breakage), 60 % higher flexural strength (ability to be bent or twisted without breaking) and 126 % increased flexural modulus (ultimate level of ability to be bent or twisted). The NIST researchers also said that, unlike many chemical fire retardants, nanocomposites produce no increase in carbon monixide or soot during combustion. News Briefs