Abstract: In an aqueous suspension of magnesium hydroxide, zinc aluminate was formed by the reaction between zinc sulfate and sodium and coated on the surface of magnesium hydroxide. The zinc aluminate coated magnesium hydroxide was added into PVC as a smoke suppression agent. The alkaline of the coated magnesium hydroxide was weaker and the oil absorption value was lower than plain magnesium hydroxide. When 20 phr zinc aluminate coated magnesium hydroxide was used, the total smoke release amount of PVC was 10.36 m2/m2, which was 24 % and 48 % lower than the systems containing 2 phr of zinc aluminate and 20 phr of plain magnesium hydroxide, respectively. The smoke density rates of above three systems were 65, 76, and 90, respectively.

Key words: zinc aluminate, poly(vinyl chloride), encapsulation, magnesium hydroxide, smoke suppression