Abstract: A composite flame retardant composed of ammonium polyphosphate (APP), pentaerythritol (PER) and potassium dodecyl monophosphate modified zinc aluminum double hydroxide (ZnAl-LDH-PK) was prepared with the intumescent flame retardant IFR synergistic flame retardant polystyrene (PS), and the flame retardant properties and combustion performance of polystyrene under different ratios of the two were studied. The results showed that the appropriate ratio of ZnAl-LDH-PK and IFR synergistically acted on the composite material, can promote the material with better thermal stability and carbon formation ability; when the component was PS, 22% IFR, 3% ZnAl-LDH-PK, its Gmited oxygen index LOI reached 35, and the total heat release and total smoke generation were reduced by 28% and 38%, respectively, compared with pure PS, improving the fire resistance. The SEM results confirmed that ZnAl-LDH-PK and IFR synergistically formed a highly expanded and continuous dense carbon layer in the composite.

Key words: polystyrene, layered double hydroxide, intumescent flame retardant, synergistic effect