LaFeO_3的合成及其在软质PVC中的阻燃应用

Synthesis of LaFeO_3 and Its Application in Poly(vinyl chloride) as Flame Retardants

采用高温煅烧法合成了钙钛矿型铁酸镧(LaFeO3)。探讨了煅烧温度及时间对反应产物的影响,通过X射线衍射(XRD)对LaFeO3进行了表征,确定高温煅烧的最佳条件为800℃下煅烧4 h。通过极限氧指数(LOI)、烟密度等级(SDR)及锥形量热(CONE)测试研究了LaFeO3对软质PVC阻燃及消烟性能的影响,使用热重分析(TGA)考察了LaFeO3对PVC热降解过程的影响。结果表明:LaFeO3能有效地降低PVC燃烧过程中的发烟量,使样品燃烧的热释放速率(HRR)、烟释放速率(SPR)以及总烟释放量(TSP)等明显降低;LaFeO3主要在PVC降解的第二阶段发挥阻燃消烟作用,大量稳定的残炭的生成是LaFeO3具有优异消烟性能的主要原因。

LaFeO3 which has a perovskite structure was synthesized with a sintered method at high temperature. The effects of calcination temperature and time on the products were discussed, and the product was also characterized by X-ray diffraction（XRD） analysis. The results show that： the optimum reaction conditions for synthesis of LaFeO3 are calcined at 800℃ for 4 h. The effects of LaFeO3 on the flame retardant and smoke suppression of flexible polyvinyl chloride（PVC） were studied using the limiting oxygen index（LOI） test, the smoke density rating（SDR） test, and the cone calorimeter（CONE） test. The effect of LaFeO3 on the thermal degradation of PVC was also studied using thermogravimetric analysis（TGA）. The results show that LaFeO3 can effectively reduce the amount of smoke in the PVC combustion process. The heat release rate（HRR）, the smoke production release rate（SPR） and total smoke production（TSP） are also significantly decreased. LaFeO3 can promote PVC to generate a large number of stable char residues in the second degradation step, and this is the main reasons for LaFeO3 can be used as an excellent flame retardant and smoke suppression for PVC.