反相微乳液法制备纳米Al2O3颗粒及其形成反应机理的研究

通过聚乙二醇辛基苯基醚(曲拉通X-100)/正丁醇/环己烷/水溶液形成的体系, 采用反相微乳液法合成了Al₂O₃纳米粒子. 对前驱体进行热分析(TG-DTG-DTA), 确定了合适的煅烧温度为1150 ℃. 采用X射线衍射(XRD)、透射电镜(TEM)、紫外可见分光光度法(UV-vis)分别对产物的结构、粒度和形貌进行了表征, 考察了微乳液中水与表面活性剂的物质的量之比(ω_o)、煅烧温度和煅烧时升温速率等关键因素对产物形貌和晶相的影响, 并通过分析进一步揭示了Al₂O₃纳米粒子的形成机理. 结果表明, 控制ω_o为10、煅烧温度为1150 ℃可得到分散性好、粒径分布均匀的Al₂O₃纳米粒子, 且2 ℃/min的升温速率更有利于产物向稳定的α晶相转变.

Study on Preparation and Formation Mechanisms of Al2O3 Nanoparticles by Reverse Microe-mulsion

Al₂O₃ nanoparticles have been prepared by polyethylene glycol octylphenyl ether (Triton X-100)/n-butyl alcohol/cyclohexane/water reverse microemulsion. The result of thermal analysis of the precursor products showed that the proper calcination temperature was 1150 ℃. The structures and morphologies of Al₂O₃ nanoparticles were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM) and UV-vis spectrophotometry. The influences of molar ratio of water to surfactant (ω_o), calcination temperature and heating rates on the morphologies and sizes of the product were studied, and the formation mechanisms in the reverse microemulsion were also discussed. The results show that the obtained Al₂O₃ powder has no obvious agglomeration and narrow particle size distribution under the condition of ω_o＝10, T＝1150 ℃, and heating rate of 2 ℃/min is propitious to the phase change of a stable α-Al₂O₃.