磷系阻燃剂插层镁铝水滑石增强环氧树脂的阻燃性能

Flame Retardancy of Epoxy Resin Enhanced by Intercalation of Magnesium Aluminum Hydrotalcite with Phosphorous Flame Retardants

聚磷酸铵(APP)、9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)、三聚氰胺聚磷酸盐(MPP)与镁铝型水滑石(MAH)插层,制得插层复合物(APP-MAH-6H,DOPO-MAH-6H,MPP-MAH-6H),复合物与环氧树脂(EP)通过搅拌共混热固化制备了EP/DOPO-MAH-6H、EP/APP-MAH-6H和EP/MPP-MAH-6H,并用锥形量热、垂直燃烧、极限氧指数、扫描电子显微镜(SEM)和拉曼光谱等表征手段对其结构和性能进行表征,探究了它们的阻燃性能。实验结果表明:与纯EP相比,EP/DOPO-MAH-6H、EP/APP-MAH-6H和EP/MPP-MAH-6H的热释放速率峰值由1079.2 kW/m^(2)分别下降到481.3、445.7和385.8 kW/m^(2),极限氧指数(LOI)由25.1%分别提升到32.2%、32.9%和33.8%。此外,在垂直燃烧UL-94测试中,EP/DOPO-MAH-6H、EP/APP-MAH-6H和EP/MPP-MAH-6H的等级均达到了V-0水平。通过SEM可知,EP/DOPO-MAH-6H、EP/APP-MAH-6H的残炭形貌大而连续,EP/MPP-MAH-6H的残炭形貌整体致密且连续。由拉曼光谱测试结果可知,3种EP复合材料形成了连续、优质的炭层,能有效隔离燃烧过程中氧气和热量向内部基质的传递。因此,3种磷系插层复合物均能有效地提升环氧树脂的阻燃性。

Ammonium polyphosphate(APP),9,10-dihydro-9-oxa-10-phosphame-10-oxide(DOPO),and melamine polyphosphate(MPP)were intercalated into magnesia-aluminum hydrotalcite(MAH)to obtain intercalation complexes(APP-MAH-6H,DOPO-MAH-6H,MPP-MAH-6H).EP/DOPO-MAH-6H,EP/APPMAH-6H,and EP/MPP-MAH-6H were prepared by mixing the intercalation complexes and hot curing with epoxy resin(EP).The structures and properties of EP/DOPO-MAH-6H,EP/APP-MAH-6H,and EP/MPPMAH-6H were characterized by cone calorimetry,vertical combustion,limiting oxygen index(LOI),scanning electron microscopy(SEM)and Raman spectrum,and their flame retardant properties were investigated.The experimental results show that:Compared with pure EP,the peak heat release rate(pHRR)of EP/DOPOMAH-6H,EP/APP-MAH-6H and EP/MPP-MAH-6H decreased from 1079.2 kW/m^(2) to 481.3,445.7 and 385.8 kW/m^(2),respectively,and the LOI increased from 25.1% to 32.2%,32.9% and 33.8%,respectively.In addition,in the UL-94 test of vertical combustion,EP/DOPO-MAH-6H,EP/APP-MAH-6H and EP/MPPMAH-6H all achieved V-0 levels.According to SEM,the morphologies of char residue for EP/DOP-MAH-6H and EP/APP-MAH-6H are large and continuous,while the morphologies of char residue for EP/MPP-MAH-6H are dense and continuous.The test results of Raman spectrum show that the three EP composites form a continuous,high-quality carbon layer,which can effectively isolate the transfer of oxygen and heat to the internal matrix during the combustion process.Therefore,the addition of the three phosphorus intercalation complexes can greatly improve the flame retardancy of epoxy resin.