Journal of Research of the National Institute of Standards and Technology
MD 20899-0001; telephone: 301/975-3572 . 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 NIST plans to host a conference in the near future where scientists and plastics industry representatives will discuss setting up a research consortium to further study nanocomposite flame retardancy properties. For more information, contact Jeffrey W. Gilman, B258 Polymer Building, NIST, Gaithersburg, MD 20899-0001, (301) 975-6573, . RESEARCH MAY HELP HUNT FOR INTERSTELLAR IRON Scientists from NIST, Oxford University, and the University of Bonn recently made spectral observations of the iron deuteride (FeD 2 ) molecule near 6.9 THz (43 m) using laser magnetic resonance spectroscopy. These are the highest frequency far-infrared LMR observations ever recorded and the first FIR observations of a vibrational bending spectrum made using LMR spectroscopy. The FeD 2 observations are important because they provide accurate spectral information for researchers to search for iron in the interstellar medium-an existence that has yet to be documented. In addition, the development of the technology used to make the observations opens up significant new opportunities for important measurements in radio astronomy and upperatmospheric research. The international team modified a spectrometer so that it allows measurements at frequencies as high as 9 THz, just about the same as the upper limit for radio astronomy measurements. This expanded range of LMR measurement now covers fine-structure transitions in a number of atoms and molecules, providing the potential for making the exacting laboratory frequency measurements needed to support searches for these species in space. Closer to Earth, the researchers soon may use their new ability to assess the level of chlorine oxide (ClO), an important molecule in the upper atmosphere. ClO has a fine structure transition at 8.2 THz, which should be detectable by the improved LMR spectroscopy. This 709