NIST Time|NIST Home|About NIST|Contact NIST

HomeAll Years:AuthorKeywordTitle2005-2010:AuthorKeywordTitle

Polymer Combustion and Flammability - Role of the Condensed Phase. Invited Topical Review.


pdf icon 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.