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Preparation and Flame Resistance Properties of Revolutionary Self-Extinguishing Epoxy Nanocomposites Based on Layered Double Hydroxides.


pdf icon Preparation and Flame Resistance Properties of Revolutionary Self-Extinguishing Epoxy Nanocomposites Based on Layered Double Hydroxides. (701 K)
Zammarano, M.; Franceschi, M.; Bellayer, S.; Gilman, J. W.; Meriani, S.

Polymer, Vol. 46, No. 22, 9314-9328, October 2005.

Keywords:

nanocomposites; epoxy resins; flame resistance; clay; self-extinguishment; flame retardants; experiments; x-ray diffraction; thermal properties; cone calorimeters; thermogravimetrical analyses

Abstract:

Layered double hydroxides/epoxy (LDHs/EP) nanocomposites were prepared from organo-modified LDHs, a diglycidyl ether of bisphenol A monomer (DGEBA) and amine curing agents. The organo-modified LDHs were obtained by ionic exchange of a magnesium-aluminum carbonate LDH in an acid medium. X-ray diffraction and transmission electron microscopy showed a dispersion of the layers at a nanometer scale, indicating the formation of LDH/EP nanocomposites. The thermal degradation and flame resistance properties of LDH/EP nanocomposites, montmorillonite-epoxy (MMT/EP) nanocomposites, LDH/EP microcomposites and aluminum hydroxide-epoxy microcomposites were compared by thermogravimetrical analyses, simultaneous thermal analyses, UL94 and cone calorimeter tests. Only LDH/EP nanocomposites showed self-extinguishing behavior in the horizontal UL94 test; LDH/EP microcomposites and MMT/EP nanocomposites samples burned completely showing that the unique flame resistance of LDH/EP nanocomposites is related to both the level of dispersion and the intrinsic properties of LDH clay. Furthermore, cone calorimeter revealed intumescent behavior for LDH/EP nanocomposites and a higher reduction in the peak heat release rate compared to MMT/EP nanocomposites.