纳米镁铝水滑石的制备及其对聚氨酯阻燃性能的影响

采用液相沉淀法制备纳米镁铝水滑石微粉,利用XRD、TEM和TG对试样进行表征,研究了反应温度、干燥时间以及碳酸根浓度对镁铝水滑石纳米晶的影响.镁铝水滑石微粉经硅烷偶联剂KH550表面改性后填充到聚醚多元醇组合料中,采用原位聚合法制备出镁铝水滑石/软质聚氨酯纳米复合材料,研究了纳米镁铝水滑石对聚氨酯的阻燃效果及阻燃机理,并与Al(OH)_3阻燃效果进行对比.实验结果表明,晶粒尺寸随反应温度的升高而增大;干燥5h镁铝水滑石的热分解性能较好;适当提高碳酸根浓度可以改善镁铝水滑石晶体规整度;硅烷偶联剂KH550用量为5%时对镁铝水滑石表面改性效果最好;镁铝水滑石阻燃剂填充软质聚氨酯复合体系的阻燃效果要优于Al(OH)_3阻燃剂.

Investigation on preparation of nano Mg-Al hydrotalcite and its flame retardancy to polyurethane

Mg-Al hydrotalcite nanocrystalline was synthesized by the liquid coprecipitation method and characterized by XRD, TEM and TG. The effects on the crystal from different reaction conditions,such as reaction temperature, drying time and carbonate ion concentration, were investigated systematically. The samples were modified by silane coupling agent KH550, and then filled into polyether polyol to synthesize hydrotalcite/polyurethane nano-composites. The flame retardancy of hydrotalcite, in comparison to Al(OH)_3, was studied. Results indicated that the higher reaction temperature, the bigger crystal size; the thermal decomposition performance of hydrotalcite is better after drying 5h; the crystal regularity improved with the increasing carbonate ion concentration. Moreover, it is found that the optimum dosage of silane coupling agent KH550 is 5%. Finally, the results of flame-retardant test showed that the flame retardancy of Mg-Al hydrotalcite is better than that of Al(OH)_3.