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New Flame Retardants Consortium: Flame Retardant Mechanism of Silica. Final Report (NISTIR 6357)



Jeffrey W. Gilman, Takashi Kashiwagi, Marc R. Nyden, Richard H. Harris Jr.


The results of a two year research project carried out with the "New Flame Retardants Consortium" are reported. This investigation into the flame retardant mechanism of silica gel and other forms of silica has determined that the silica FR mechanism is comprised of two main effects. The first is a reduction in the transport rate of the thermal degradation products by dramatically increasing the viscosity of the polymer melt due to hydrogen bonding of surface silanol groups and entanglement of polymer chains within the large pores of silica gel. Second is the reduction in thermal diffusivity of the sample near the surface due to gradual accumulation of silica, which acts as a thermal insulation layer.
NIST Interagency/Internal Report (NISTIR) - 6357
Report Number


flame retardants, fire retardants, silica


Gilman, J. , Kashiwagi, T. , Nyden, M. and Harris, R. (1999), New Flame Retardants Consortium: Flame Retardant Mechanism of Silica. Final Report (NISTIR 6357), NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 15, 2024)


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Created June 1, 1999, Updated November 10, 2018