Abstract: In this paper, polystyrene (PS)-based flame-retardant compounds were prepared by incorporation of magnesium hydroxide (MH) and microencapsulated red phosphorus (MRP) as flame-retardant additives. The effect of the two flame-retardant additives on flame-retardant and mechanical properties of PS was investigated by limiting oxygen index, vertical burning tests, thermal analysis and mechanical measurements. The results indicated that the flame-retardant properties were improved with an increase of the content of flame-retardant additives, but the mechanical properties tended to decline. The limiting oxygen index was improved by 25 % compared with that of pure resin when 60 phr of flame-retardant additives was introduced, and the compound revealed a compact char layer after combustion.

Key words: polystyrene, magnesium hydroxide, microencapsulated red phosphorus, flame retardancy, compound