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Flammability of Nanocomposites: Effects of the Shape of Nanoparticles.


pdf icon 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.