微胶囊红磷和聚苯醚对高抗冲聚苯乙烯的协同阻燃作用

利用微胶囊红磷(MRP)和聚苯醚(PPO)来提高高抗冲聚苯乙烯(HIPS)的阻燃性能, 通过熔融共混法制备了一系列不同组成的MRP-PPO/HIPS复合材料。采用水平燃烧、垂直燃烧、氧指数、锥形量热分析、高温热分解实验等方法研究了复合材料的阻燃性能。研究表明, 阻燃剂用量相同时, 在HIPS基体中同时加入MRP和PPO得到的复合材料比单独加入MRP或PPO得到的复合材料具有更好的阻燃性能。当MRP-PPO/HIPS的质量比为10:20:70时, 复合材料的氧指数为23.9%, 水平燃烧级别达到FH-1级, 垂直燃烧级别达到FV-0级, 阻燃性能达到最佳。MRP用量过多时, 复合材料的阻燃性能下降。研究认为, PPO和MRP对HIPS具有较强的协同阻燃作用。两者以适当比例并用时能够使复合材料在燃烧时的热释放速率和燃烧热大幅度减小, 降低了气相燃烧区的温度, 起到气相阻燃作用。同时, 复合材料在热分解和燃烧时能够生成连续和致密的炭层, 抑制了燃烧过程中的热量传递和物质交换, 起到凝聚相阻燃作用。因此, 复合材料的阻燃性能显著改善。

Synergistic effect of MRP and PPO on the flame retardancy of HIPS

Microencapsulated red phosphorus (MRP) and poly(phenylene oxide) (PPO) were used to improve the flame retardancy of high impact polystyrene (HIPS). A series of MRP-PPO/HIPS composites with different compositions were prepared by melt-compounding. The flame retardancy of the composites was investigated by horizontal burning, vertical burning, oxygen index, cone calorimetry and high temperature pyrolysis experiments. It is indicated that the composite containing both MRP and PPO exhibits better fire retardancy than its counterpart containing only PPO or MRP at the same flame retardant contents. When the mass ratio of MRP-PPO/HIPS is 10:20:70, the oxygen index of the composite is 23.9% and the horizontal burning rating and vertical burning rating of the composite can reach FH-1 and FV-0, respectively. The composite with this composition displays the optimum flame retardancy. Excessive contents of MRP can decrease the fire retardancy of the composite. It is believed that there is strong synergistic effect between MRP and PPO on the flame retardancy of HIPS. The coexistence of MRP and PPO with suitable mass ratio can decrease the heat release rate and combustion heat of the composite considerably, which lowers the temperature in the gaseous combustion zone and leads to increased flame retardancy in the gas phase. Meanwhile, the composite can produce a continuous and compact charred residue layer during pyrolysis and combustion. This char layer suppresses heat transfer and mass exchange and improves the flame retardant effect in the condensed phase. As a result, the flame retardancy of the composite is improved considerably.