Layered Double Hydroxides as Flame Retardant and Thermal Stabilizer for Polymers

Abstract

Layered double hydroxides (LDH) has wide applications as non-toxic and halogen-free flame retardant for various resins and highly efficient thermal stabilizer for halogen-containing polymers. This review will discuss some public patents and relevant papers on the flame retardancy and the thermal stability of LDH/polymer composites when the LDHs with different chemical compositions are used as the additive in the polymer matrix. We have summarized these related LDHs in two tables: one for flame retardant and the other for thermal stabilizer.

Inorganic nanolayers: structure, preparation, and biomedical applications

“…74 They have been applied alone and in combination with polymers for fire control. 74,75 Gao et al developed flame-retardant nanocomposite-based LDHs with different anions like nitrate, carbonate, chloride, and sulfonate, and combined them with a high-density polyethylene polymer. 75 There are many other LDHs and polymer composites that have been developed and applied as flame retardants.…”

High Performance Layered Inorganic Flame Retardants: a Review

“…[32] The endothermic decomposition process of magnesium hydroxide (MH) and aluminum hydroxide (ATH) can decrease the temperature of the burning material and release water into the gas phase to dilute the flame. [33] In addition, the presence of anhydrous alumina can help acid-catalyzed dehydration of some polymers and consequently enhance char formation. Since both anhydrous alumina (Al2O3) and magnesia (MgO) are white and highly refractory powders, they provide heat insulation by reflecting heat when they accumulate on a surface.…”

Continuous flow synthesis and cleaning of nano layered double hydroxides and the potential of the route to adjust round or platelet nanoparticle morphology

“…22 Last but not least, due to the water and carbon dioxide release upon calcination, the reaction to ceramic-tar-like materials at high temperatures and the overall endothermic nature of the reactions when heating up the material, makes these structures promising candidates for ame-retardants, bearing the potential to ultimately replace halogenated organic ame-retardants in the future. [23][24][25] For all these applications, it is desired to make the LDH entities as small as possible, i.e., synthesise nano-LDH, as this comes with the advantage of a highly reactive surface and the fact that more active spots (LDH particles) are available for a given mass of material, i.e., the smaller the particles, the higher the chance to achieve a very nely and homogeneously distributed lling e.g. within polymers for ame retardancy.…”