Effect of Triaryl Phosphate, Zinc and Zinc Borate on Fire Properties of High Impact Polystyrene and High Impact Polystyrene-Polyphenylene Oxide Blend (Modified-Polyphenylene Oxide

Samples of m-PPO (virgin and flame retarded) and high impact polystyrene blended with zinc and zinc borate (2ZnO·3B ₂ O ₃ ·3.5H ₂ O), were pre pared. The effect of triaryl phosphate on the flame retardancy of PPO-HIPS in conjunction with zinc and zinc borate was studied. For polystyrene zinc borate shows some reduction in smoke generation. Zinc, however does not show any effect on smoke generation for high impact polystyrene. Triphenyl phosphate shows minimal flame retardancy in HIPS which is not enhanced by zinc. Addition of zinc gives an increase in oxygen index for FR m-PPO, whereas zinc borate decreases the OI values. Zinc borate may sequester triaryl phos phate and thus eliminate its vapor phase activity. Zinc borate shows a signifi cant reduction in smoke generation and rate of heat release for m-PPO.