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New Approaches to the Development of Fire-Safe Materials.


pdf icon New Approaches to the Development of Fire-Safe Materials. (1043 K)
Morgan, A. B.; Gilman, J. W.; Nyden, M. R.; Jackson, C. L.

NISTIR 6465; 22 p. February 2000.

Available from:

National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161.
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Order number: PB2000-101949

Keywords:

nanocomposites; thermogravimetric analysis; clay; polymers

Abstract:

Thermoplastic polyetherimide-clay nanocomposites were synthesized from 1,3-phenylenediamine and bisphenol A dianhydride using an in situ approach. Two types of organically treated clays were utilized to synthesize these nanocomposites. The two organically treated clays were montmorillonite clays treated with the ammonium salts of n-dodecylamine or 12-amino-1-dodecanoic acid. The dispersion of the clay in the polyetherimide was analyzed by wide-angle x-ray scattering and transmission electron microscopy. The results showed that the clay treated with the ammonium salt of 12-amino-1-dodecanoic acid gave a well-dispersed intercalated nanocomposite while the clay treated with the ammonium salt of n-dodecylamine gave a well-dispersed immiscible blend. These nanocomposites were then analyzed by thermal gravimetric analysis for their thermal stability. Computational and experimental approaches were developed to explore the nature and consequences of thermally induced changes that occur in the condensed phase of burning polymers. A computational strategy for evaluating molecular weight distributions (which should enable us to calculate the melt viscosity during burning) from molecular dynamics simulations was developed based on a simple differential equation for the time dependence of the number average degree of polymerization, x, derived by Boyd. The experimental effort, which we hope to be able to use in validating the predictions of this model, was successful in obtaining real-time measurements of the mid-infrared spectra of burning polymers. The condensed phase spectra of nylon 6 and a nylon 6/clay nanocomposite were measured using a fiber optic reflectance probe while they were burning on the cone calorimeter.