Polymer Combustion and Flammability - Role of the Condensed Phase. Invited Topical Review.
Polymer Combustion and Flammability - Role of the
Condensed Phase. Invited Topical Review.
(1589 K)
Kashiwagi, T.
Combustion Institute. Symposium (International) on
Combustion, 25th. Proceedings. July 31-August 5, 1994,
Irvine, CA, Combustion Institute, Pittsburgh, PA,
1423-1437 pp, 1994.
Keywords:
combustion; fire hazards; flammability; burning rate;
radiative heat transfer; degradation; test methods;
flame spread; flame retardants; oxygen concentration
Abstract:
The combustion process of polymers is a complex coupling
of energy feedback from a flame to the polymer surface
with gasification of the polymer to generate combustible
degradation products. Although there are extensive
studies of the effects of wind velocity, gas phase
oxygen concentration, external thermal radiation, and
gravity on the combustion of polymers, the effects of
polymer characteristics on combustion and flammability
are not nearly as well understood as those in the gas
phase. At present, detailed governing equations for
continuity, momentum, energy, and chemical species
concentration in the gas phase can readily be written
with appropriate boundary conditions and the solutions
can be derived for various cases. However, even those
governing equations cannot be derived for the condensed
phase without understanding of the governing chemical
and physical processes which control the gasification of
polymers. This paper concentrates on describing various
observed phenomena in polymers (which have been often
ignored or neglected) during their combustion some or
all of which might have significant effects on the
burning rate and flammability properties. Due to a lack
of understanding of the basic combustion mechanisms of
polymers, theoretical models able to predict combustion
phenomena and flammability properties are not available.
In order to overcome this problem, global material
characteristics are currently measured by well-defined
test methods and the results are used as inputs to fire
growth models intended to predict behavior of the
materials in specific fire scenarios. To improve the
fire performance of polymers, a non-halogenated
char-forming flame retardant approach is suggested and
its benefits are discussed.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899