硅烷偶联剂对纳米氧化锌的表面改性研究

采用硅烷偶联剂KH-570对纳米ZnO进行表面改性,研究了硅烷偶联剂用量、pH值、时间及反应温度等因素对纳米ZnO表面改性的影响,利用亲油化度实验、红外光谱(IR)、热重(TG)、透射电镜(TEM)等手段表征了纳米ZnO的改性效果和结构。红外光谱和热重研究表明,KH-570以化学键合的方式结合在纳米ZnO的表面,并形成了有机包覆层。经测量,纳米ZnO表面的KH-570的质量分数为4.6%;讨论了产生KH-570理论包覆量与实际包覆量差异的原因。TEM图表明经KH-570改性过的纳米ZnO的分散性大大提高;亲油化度实验表明,当硅烷偶联剂用量为6%,pH值为6.5,反应温度为85℃,反应2 h时,纳米ZnO改性效果最好。

纳米氧化锌的微乳液法制备

Size-controlled nanometer zinc oxide were successfully prepared by a water-in-oil(w/o) microemulsion process by flowing gaseous ammonia(NH3) into microemulsion zones of zinc nitrate solution.The w/o microemulsion was formed by Triton X-100 / n-octanol / cyclohexane / zinc nitrate solution.The obtained nanometer zinc oxide was characterized by thermogravimetric-differential thermal analysis(TG-DTA),Fourier transform infrared spectroscopy(FT-IR),X-ray powder diffraction(XRD),and transmission electron microscopy(TEM).The size of nanometer zinc oxide was correlative with bake temperature,the ratio of n(H2O) / n(TX100) and zinc ion concentration.The results showed that the nanometer zinc oxide having average size of about 20 ～ 40 nm was obtained by vacuum drying at 110 ℃ for 4 h and baking at 300 ℃ of the nanometer zinc oxide precursor synthesized using(w/o) microemulsion process with zinc ion concentration of 1.5 mol/L and the ratio of n(H2O) / n(TX100) being 8 at 25 ℃.

化学沉淀法制备纳米二氧化硅

采用硅酸钠为硅源,氯化铵为沉淀剂制备纳米二氧化硅。研究了硅酸钠的浓度、乙醇与水的体积比以及pH值对纳米二氧化硅粉末比表面积的影响,并用红外、X射线衍射和透射电镜对二氧化硅粉末进行了表征。研究结果表明在硅酸钠浓度为0.4mol/L,乙醇与水体积比为1∶8,pH值为8.5时可制备出粒径为5～8nm分散性好的无定形态纳米二氧化硅。

纳米二氧化硅的制备及表面修饰的研究进展

纳米二氧化硅是一种性能优异、应用广泛的无机纳米材料。介绍了纳米二氧化硅的主要制备方法(气相法、溶胶-凝胶法、沉淀法、反相微乳液法)的原理及优缺点,并全面综述了其表面物理和化学修饰改性的主要方法,最后展望了纳米二氧化硅的发展前景。