富马酸根插层镁—铝类水滑石的共沉淀法制备及性质表征

Mg-Al Layered Double Hydroxides Intercalated by Fumaric Acid Anion via Co-precipitation Preparation and Properties Characterization

富马酸根插层类水滑石(LDHs)是一种具有较好聚合物相容性和热稳定性等潜在应用价值的多功能复合材料。本文通过密度泛函理论对富马酸根离子静电势和离子尺寸的分析,预测了富马酸根插入LDHs的离子尺寸约为0.802 nm,并从热力学角度说明了富马酸根离子与乙烯、氢自由基加成反应的可能性;以低成本氯化物为原料,采用一步共沉淀法成功制备了富马酸根离子插层LDHs,并结合XRD讨论了加料方式、镁铝比例、陈化时间、加料速度、镁离子浓度和富马酸根离子浓度对所合成类水滑石结构的影响,揭示了富马酸根插层LDHs的形成过程;透射电镜和选区电子衍射说明合成的类水滑石为片状多晶体,红外光谱进一步证明了富马酸根的成功插层,热重分析表明其在氮气中热稳定性较好,具有成碳性,可作为阻燃填料加以应用。本研究为插层LDHs的设计奠定了一定的理论方法基础,也会对富马酸根离子插层LDHs和我国氯化镁资源的实际开发利用起到一定的推动作用。

Layered double hydroxides(LDHs)intercalated by fumaric acid anion(FAa)is a kind of multifunctional composites with potential utilization values like good polymer compatibility and thermal stability.With electrostatic potential and dimension analysis via density functional theory,the size of FAa in LDHs was proposed to be 0.802 nm,and the addition reactions of FAa with ethylene and hydrogen radical were proved to be possible thermodynamically.In this paper,CAa intercalating LDHs(FLDHs)was successfully prepared by one-step co-precipitation with the low-cost chlorides.Through powder x-ray diffraction analysis,the effects of feeding type,magnesium/aluminum ratio,aging time,feeding rate,magnesium and FAa concentration on FLDHs structure were systemically investigated,and the formation process of FLDHs was also discovered.Transmission electron microscope and selected area electronic diffraction showed that FLDHs was polycrystal with sheet morphology.The successful intercalation of FAa was confirmed by infrared spectrum.Thermal gravity analysis demonstrated that FLDHs possesses good thermal stability and carbonization property,and it can be applied as flame retardancy filler.This paper may lay a theoretical method foundation on the design of other organics intercalating LDHs,and can also promote the practical utilization of the FLDHs and China's rich magnesium chlorides resource.