Nanocomposites: A Revolutionary New Flame Retardant Approach.
Nanocomposites: A Revolutionary New Flame Retardant
Gilman, J. W.; Kashiwagi, T.; Lichtenhan, J. D.
SAMPE Journal, Vol. 33, No. 4, 40-46, August 1997.
nanocomposites; flame retardants; clay; cone
calorimeters; fire retardants; heat release rate;
physical properties; char; thermal stability; carbon
To evaluate the feasibility of controlling polymer
flammability via a nanocomposite approach, we have
examined the flammability properties of nylon-6
clay-nanocomposites. The fire retardant (FR) properties
of this new class of materials, organic-inorganic
nanocomposites, are reported. The cone calorimeter data
show that the peak heat release rate (HRR), the most
important parameter for predicting fire hazard, is
reduced by 63 percent in a nylon-6 clay-nanocomposite
containing a clay mass fraction of only five percent.
Not only is this a very efficient FR system, but, it
does not have the usual drawbacks associated with other
FR additives. This is, the physical properties are not
degraded by the additive (clay), instead they are
greatly improved. Furthermore, this system does not
increase the carbon monoxide or soot produced during the
combustion, as many commercial fire retardants do. The
nanocomposite structure appears to enhance the
performance of the char through reinforcement of the
char layer. Indeed, transmission electron microscopy
(TEM) of a section of the combustion char from the
nylon-6 clay-nanocomposite (five percent) shows a
multilayered silicate structure. This layer may act as
an insulator and a mass transport barrier slowing the
escape of the volatile products generated as the nylon-6