纳米氧化镁对聚碳酸酯阻燃性能的影响

Effect of Nano Magnesium Oxide on Flame Retardancy of Polycarbonate

为研究碱土金属氧化物纳米材料对聚碳酸酯阻燃性能的影响,制备了聚碳酸酯/氧化镁(PC/MgO)纳米复合材料,并采用锥形量热测试、热失重分析等方法分析了纳米氧化镁(MgO)对聚碳酸酯(PC)阻燃性能和热稳定性的影响。锥形量热测试结果表明,与纯PC相比,PC/MgO纳米复合材料的二次热释放速率的峰值显著下降;纯PC的总热释放量为53.5 MJ/m^2,而PC/MgO(1.0%)纳米复合材料的总热释放量为41.9 MJ/m^2,减少了21.7%。纯PC的比消光面积(SEA)为363 m^2/kg,而PC/MgO(4.0%)纳米复合材料可以达到487 m^2/kg,增加了34.1%。加入纳米MgO能促进PC基体提前分解成炭,在材料表面形成致密的连续炭层。对比受热生成的炭层照片可知,PC/MgO纳米复合材料在燃烧后能形成表面致密的膨胀炭层,具有较好的阻燃效果。

In order to study the effect of alkaline earth metal oxides on the flame retardancy of polycarbonate(PC),small amount of nano magnesium oxide(MgO) was incorporated into PC matrix.The effect of nano magnesium oxide on flame retarding property and thermal property was characterized by cone calorimeter and thermogravimetric analysis(TGA).Cone calorimeter test revealed that a small amount of MgO(1.0%) led to significant enhancement in flame retardancy.When 1.0%MgO was introduced into the polycarbonate,the second peak of heat release rate decreased evidently.Compared with pure PC,the total heat release of PC/MgO composite decreased from 53.5 MJ/m^2 to 41.9 MJ/m^2(21.7% decreased).Compared with pure PC,the specific extinction area(SEA) of PC/MgO(4.0%) nanocomposite increased from 363 m^2/kg to 487 m^2/kg(34.1% increased).MgO could catalyze the degradation of PC matrix.Dense and continuous char layer was generated on the surface of polycarbonate matrix.The digital photographs showed that a compact and intumescent char layer was formed for PC/MgO.Therefore,the flame retardancy property was enhanced.