可膨胀石墨的氧化处理对复配阻燃PU涂层性能的影响

Effect of Oxidation Treatment of Expandable Graphite on Combustion Behavior of Flame-retardant Polyurethane Coating

将可膨胀石墨(EG)与经过氧化处理的氧化石墨(OEG)分别与APP/氢氧化镁[APP/Mg(OH)_2]、APP/氢氧化铝[Al(OH)_3]复配,并通过浇注固化的方法制备聚氨酯阻燃涂层。通过极限氧指数、锥形量热测试对复合材料的阻燃性能进行了研究,并利用扫描电子显微镜对残炭形貌进行了分析。结果表明,OEG复配聚氨酯阻燃涂层表现出良好的阻燃性能,与粒径相同的74μm石墨相比,其极限氧指数有所提高,并且热释放速率峰值从258 kW/m^2下降到228 kW/m^2[APP/Mg(OH)_2],从461 kW/m^2下降到441 kW/m^2[APP/Al(OH)_3],分别下降了11.6%和4.3%;在复配OEG后残炭更加完整致密,且膨胀高度增加。

The expandable graphite （EG） and oxidized expandable graphite （OEG） were compounded with ammonium polyphosphate （APP）/magnesium hydroxide [Mg（OH）2] and APP/ aluminum hydroxide [Al（OH）3] to prepare flam-retardant polyurethane （PU） coating, respectively. The flame-retardant properties of the composite coating were evaluated in terms of limiting oxygen index （LOI） and cone calorimeter tests. The results indicated that the presence of OEG led to a higher LOI compared with EG at the same particle size, whereas the peak heat release rate decreased dramatically. The morphology of residual char was investigated by scanning electron microscope, and the results revealed that the residual char was more integrated and compact for the composite coating containing OEG, and its expansion height was also improved.