The more widely and uniformly dispersed nanoscale plates of clay are in a polymer, the more fire protection the nanocomposite material provides
If materials scientists accompanied their research with theme songs, a team from the National Institute of Standards and Technology (NIST) and the University of Maryland (UMD) might be tempted to choose the garage punk song "Don't Crowd Me"* as the anthem for the promising, but still experimental nanocomposite fire retardants they are studying.
That's because the collaborators have demonstrated that the more widely and uniformly dispersed nanoscale plates of clay are in a polymer, the more fire protection the nanocomposite material provides.
Writing in the journal Polymer,** the team reports that in tests of five specimens—each with the same amount of the nanoscale filler (5 percent by weight)—the sample with the most widely dispersed clay plates was far more resistant to igniting and burning than the specimen in which the plates mostly clustered in crowds. In fact, when the two were exposed to the same amount of heat for the same length of time, the sample with the best clay dispersion degraded far more slowly. Additionally, its reduction in mass was about a third less.
In the NIST/UMD experiments, the material of interest was a polymer—a type of polystyrene, used in packaging, insulation, plastic cutlery and many other products—imbued with nanometer scale plates of montmorillonite, a type of clay with a sandwich-like molecular structure. The combination can create a material with unique properties or properties superior to those achievable by each component—clay or polymer—on its own.
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