硅镁复合氧化物对膨胀阻燃聚丙烯体系的协效作用

Synergistic Effects of Magnesia-silica Mixed Oxides on Intumescent Flame Retardant Polypropylene

利用水热合成法制备了3种不同硅镁含量(质量分数)的硅镁复合氧化物(Si/Mg分别为3∶1、2∶1、1∶1),利用FTIR、SEM、XRD表征了其形貌和结构。利用熔融共混法制备了硅镁复合氧化物(MS3、MS2、MS)/多聚磷酸铵(APP)/季戊四醇(PER)/聚丙烯(PP)复合材料。对比研究了3种硅镁复合氧化物对APP/PER/PP体系的协效作用,结果表明:MS3、MS2、MS均可显著提高复合材料的阻燃性能,添加量为1%时,LOI从29.90%分别提高到33.57%、32.85%、31.05%,协效效率分别为1.39%、1.32%、1.15%,UL-94等级从NR提高到V-0,随着Si/Mg比的增加,协效作用增强;MS3、MS2、MS均可增加膨胀炭层的致密性。

Three amorphous magnesia-silica mixed oxides with Si/Mg molar ratios as 3 ： 1, 2 ： 1 and 1 ： 1 were prepared through hydrothermal method. The synthetic magnesia-silica mixed oxides were characterized by FTIR, SEM and XRD. As synergistic agents, magnesia-silica mixed oxides were added into the polypropylene/ammonium polyphosphate/pentaerythritol system. The beneficial effects of magnesia-silica mixed oxides on the flame retardaney of intumescent polypropylene composite were investigated by limiting oxygen index （LOI） and vertical burning test （UL-94）. With loading MS3, MS2 and MS, LOI values increased from 29.90% to 33.57% , 32. 85% and 31.05% , and the synergistic effeetivities were 1.39% , 1.32% and 1.15% , respectively. The synergistic effect increased with increasing of Si/Mg molar ratio. Compared with the NR level of PP composite without synergistic agents, UL-94 ratings of PP composite reached V-0 level after adding three magnesia-silica mixed oxides. The char residues of PP composite with magnesia-silica oxides became tighter and more homogeneous. According to the results of EDS, contents of element P increased with element Mg appearing on the surface of char residue.