油酸修饰对纳米二氧化钛在变压器油中分散性的影响

利用油酸对纳米二氧化钛进行有机表面修饰, 将修饰后的纳米粉体超声分散到变压器油中制备纳米二氧化钛改性变压器油, 研究了表面修饰对纳米二氧化钛在变压器油中分散性的影响. 采用X射线粉末衍射(XRD)、透射电镜(TEM)、红外光谱(FT-IR)和热分析(TG)对纳米二氧化钛的形貌、结构和表面修饰状态进行表征。结果表明, 油酸与纳米二氧化钛表面以双齿桥连配位方式键合, 在纳米二氧化钛表面形成了良好的修饰层。随着修饰剂的增加, 尽管油酸在纳米二氧化钛表面的配位方式没有发生改变, 但化学包覆量明显增加, 表面油酸分子的排列也更为紧密, 从而使纳米二氧化钛粒子在变压器油中的分散性和稳定性显著提高。当钛盐与油酸摩尔比为1:24时, 二氧化钛纳米粒子可以稳定分散在变压器油中, 室温静置30 d后仍保持澄清透明。

Effect of Oleic Acid Surface Modification on Dispersibility of TiO2

Oleic acid modified TiO₂ nanoparticles were dispersed into transformer oil to prepare TiO₂ nanoparticles modified transformer oil by ultrasonic treatment. The effect of surface modification on the dispersibility of TiO₂ nanoparticles in the oil was investigated. The morphology, structure and surface modification state of TiO₂ nanoparticles were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR) and thermogravimetric method (TG). The results show that oleic acid is bound on the surface of TiO₂ nanoparticles by bidentate coordination, and an effective modification layer is formed. With the increasing of modifying agent dosage, although the coordination pattern of oleic acid on the nanoparticle surface remains, the mass fraction of chemisorbed oleic acid obviously increases. The dispersibility and stability of TiO2 nanoparticles in the oil is dramatically improved. When the molar ratio of titanium salt to oleic acid is 1:24, TiO₂ nanoparticles can be well dispersed in the transformer oil and keep transparent after aged for 30 d at room temperature.