钙掺杂镁铝水滑石的制备及其对PVC热稳定性的影响

Preparation of Ca-doped Mg Al-layered Double Hydroxides and Its Effect on Thermal Stability of PVC

采用尿素法制备钙掺杂镁铝水滑石Ca_xMg_(4-x)Al-LDHs,研究了前驱体类型、钙的含量、有机溶剂对水滑石结构和形貌的影响;采用刚果红热稳定试验和静态热老化试验测试其对聚氯乙烯(PVC)热稳定性的影响。结果表明,氯盐为前驱体制备的钙掺杂镁铝水滑石对PVC的热稳定效果优于硝酸盐;最适宜的钙掺杂物质的量比为0.6,此时PVC刚果红时间为53 min,静态热老化时间为450 min。乙二醇-水溶剂制备的水滑石可以延长PVC静态热老化时间,丙三醇-水溶剂可以延长PVC刚果红时间。

The calcium-doped magnesium-aluminum layered double hydroxides （CaxMg4-xAl-LDHs） were prepared by urea method. The effects of precursors, calcium contents and organic solvents on the structure and morphology of hydrotalcites were studied. The thermal stability of polyvinylchloride （PVC） was tested by Congo red test and static thermal aging test. The results show the thermal stability of PVC with Ca- doped MgAl-LDHs prepared by using chloride as precursors is better than that prepared by using nitrate as precursors. The Congo red time of PVC is 53 min and its static thermal aging time is 450 min, when the optimum amount of calcium doping is 0. 6 （molar ratio ）. The LDHs prepared by using ethylene glycol solution as solventcan prolong the static thermal aging time of PVC, and the glycerol-water solvent can prolong the Congo red time of PVC.