Structure, flame retarding and smoke suppressing properties of Zn-Mg-Al-CO3 layered double hydroxides.

Zn-Mg-Al-CO₃ layered double hydroxides (LDHs) have been synthesized by a new method involving separate nucleation and aging steps. The Zn-Mg-Al-CO₃ LDHs were characterized by XRD, FT-IR, ICP and TG-DTA. The limiting oxygen index and smoke density of composites of the LDHs with EVA-28 were determined. Incorporation of Zn²⁺ in the layers of the LDHs was found promoting material charring and smoke suppression. The mechanism of flame retardation and smoke suppression is discussed. The results show that Zn-Mg-Al-CO₃ LDHs have better flame retarding and smoke suppressing effects than Mg-Al-CO₃ LDHs. [ABSTRACT FROM AUTHOR]