The thermal decomposition of Mg(OH)2 at 350oC, is highly endothermic with an additional evolution of a large amount of water (about 31%).
Mg(OH)2 MgO + H2O
Due to this property Mg(OH)2 is being used in the production of polymers with low flammability. The produced water delays the combustion and at the same time the very reactive MgO produced adsorbs dangerous toxic substances that evolve during the combustion of some polymers (e.g. PVC). Well-known applications on this field are cables with flame retardant properties, where Mg(OH)2 is added during compounding to a loading of 60% w/w.
Some advantages of Mg(OH)2, in comparison to ATH (aluminum trihydrate) as described below, enhance its position in the market.
The basic advantage of Mg(OH)2 is its higher decomposition temperature, that enables the extrusion of the plastics at higher temperatures thus increasing productivity, which in turn balances the higher cost of the material. Mg(OH)2 is also used in the compounding of polymers that demand a higher process temperature, e.g. PP.
Recommended product: Natural Magnesium Hydroxide under the brand name ECOPIREN distributed by our Dutch based affiliated company Van Mannekus & Co B.V (www.ecopiren.com)