Flammability of Nanocomposites: Effects of the Shape of Nanoparticles.
Flammability of Nanocomposites: Effects of the Shape of
Nanoparticles.
(2311 K)
Kashiwagi, T.
Chapter 6;
Fire Retardancy of Polymers. New Applications of
Mineral Fillers. Chapter 6, Royal Society of Chemistry,
Cambridge, UK, 81-99 p., 2005.
Keywords:
nanocomposites; flammability; nanoparticles; polymers;
clay; carbon; dispersion; polymethyl methacrylate
Abstract:
There is a high level of interest in using nanoscale
reinforcing fillers for making polymeric nanocomposite
materials with exceptional properties. Nanocomposites
are particle-filled polymers where at least one
dimension of the dispersed particle is on the nanometer
scale. When all three dimensions are of the order of
nanometers, we are dealing with true nanoparticles, such
as spherical silica, having an aspect ratio of 1.
Another type of nanocomposite is characterized by
particles having only one dimension on the nanometer
scale. In this case, the filler is present as
sheets/layers, such as layered silicate or graphite,
which are one to a few nanometers thick and hundreds to
thousands of nanometers in the other two dimensions. At
present, the most common approach to improving
flammability is the use of layered silicates having
large aspect ratios. When two dimensions are on the
nanometer scale and the third is larger, forming an
elongated structure, we speak of nanotubes, whiskers, or
rods with a high aspect ratio. Flammability properties
of polymers have been improved with nanoscale additives
and these filled systems provide an alternative to
conventional flame retardants. It is important to
explore how the asymmetry (aspect ratio) and other
geometrical effects of nanoparticle additives influence
the flammability properties of polymer nanocomposites.
This chapter describes flammability properties of
nanocomposites based on the three different shapes of
nanoscale additives, such as nanosilica, clay, and
carbon nanotube.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899