Fire retardants layered double hydroxide

M. Zammarano, M. Franceschi, F. Mantovani, A. Minigher, M. Celotto, and S. Meriani, Flame resistance properties of layered-double-hydroxides/epoxy nanocomposites. In Proceedings of the 9th European Meeting on Fire Retardancy and Protection of Materials, ed. M. Le Bras (Villeneuve D Ascq, France USTL Pub., 2003), pp. 17-19. 

Fire retardant properties of polymer/layered double hydroxide nanocomposites... 

Fire retardant properties ofpolymer/layered double hydroxide nanocomposites 345... 

C. Manzi-Nshuti, J. M. Hossenlopp, and C. A. Wilkie, Comparative study on the flammability of polyethylene modified with commercial fire retardants and a zinc aluminum oleate layered double hydroxide. Polymer Degradation and Stability, 94 (2009), 782-8. 

C. Nyambo, P. Songtipya, E. Manias, M. M. Jimenez-Gasco, and C. A. Wilkie, Effect of MgAl-layered double hydroxide exchanged with linear alkyl carboxylates on fire-retardancy of PMMA and PS. Journal of Materials Chemistry, 18 (2008), 4827-38. 

The combinations of nanocomposite formation with a variety of conventional fire retardants, including halogen, phosphorus, mineral fillers, and other systems, have been examined and are reported in other places in this book. We feel that this combination approach must continue and will involve other nano-dimensional materials, including other clays, snch as the layered double hydroxides, polyhedral silsesquioxanes (POSSs), carbon nanotnbes and spherical nanoparticles, and other putative flame retardants. 

In light of the issues with natural clays, one likely trend is an increase in the use of synthetic clays, such as fiuorinated synthetic mica, magadiite, and layered double hydroxides (LDH). This last clay, since it has the potential to release water under fire conditions [much like Mg(OH)2 or Al(OH)3], may find even more use in flame retardant applications. Cost issues and limited sources for synthetic clays will slow the adaptation of these materials, so most of the work will probably be seen in the patent or open literature. More work will be seen for nanocomposites containing nanofillers, such as carbon nanotubes and nanofibers, and these will probably also be combined with additional fiame retardants. 

Layered double hydroxides (LDH) are another emerging class of layered crystals due to their wide range of applications in catalysis, sorbent, ion exchangers, stablizer and fire retardance [81, 82]. The LDHs have a brucite-like structure, where divalent octahedrally coordinated M(II) ions are partially substituted by trivalent M(III) ions. As a result, the positively charged metal oxide/hydroxide layers are neutralized by other charge-balancing anions. The general chemical formula of LDHs is [M ", M " (0H)J i+(A ) -nH,0 where, M = Li+, Mg, Co, Zn, Ni, etc. M + = Al +, Cr , Fe, etc., and A = Cl, NOj, COj, , etc. [83]. The... 

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