Preparation and Flame Resistance Properties of Revolutionary Self-Extinguishing Epoxy Nanocomposites Based on Layered Double Hydroxides.
Preparation and Flame Resistance Properties of
Revolutionary Self-Extinguishing Epoxy Nanocomposites
Based on Layered Double Hydroxides.
Zammarano, M.; Franceschi, M.; Bellayer, S.; Gilman, J.
W.; Meriani, S.
Polymer, Vol. 46, No. 22, 9314-9328, October 2005.
nanocomposites; epoxy resins; flame resistance; clay;
self-extinguishment; flame retardants; experiments;
x-ray diffraction; thermal properties; cone
calorimeters; thermogravimetrical analyses
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.