双环型中空纳米SiO^(2)微球的制备及性能研究

Preparation and properties of double-ring structure hollow silica nanospheres

采用Stöber法,通过TEOS的水解-缩聚反应制备单壳型中空纳米SiO^(2)微球(HSN),以其为内核基体和引入DVB交联剂,采用逐步包裹法成功制备了双环型中空纳米SiO^(2)微球。通过X射线衍射仪、扫描电子显微镜、透射电镜、氮气吸附-脱附、热常数分析等手段对制备得到的材料进行微观结构和性能表征。结果表明:DVB含量为0.2 mL时,制备的中空球壳层结构较疏松,层间距为18 nm,比表面积为59.81 m^(2)/g;DVB含量为0.3 mL时,中空球形貌粗糙、壳层致密、孔体积下降,层间距为35 nm,比表面积为61.63 m^(2)/g;随着层间距离的增加,双环型HSN热导率降低,可低至0.0252 W/(m·K);双环型HSN可以有效降低涂层的热导率,当掺量为8%时,热导率降低85%,在保温隔热领域具有很大的应用潜力。

Single-shell structure hollow silica nanospheres(HSN)are prepared using Stöber method by hydrolyzation-polycondensation of TEOS.Double-ring structure HSN are successfully prepared with single-shell structure HSN as core matrix and adding proper crosslinking agent by stepwise wrapping synthesis method.The microstructure and properties of the as-synthesized products are characterized by XRD spectroscopy,scanning electron microscopy,transmission electron microscopy,nitrogen adsorption-desorption isotherm and thermal conductivity analysis.When the DVB content is 0.2 mL,the shell of the hollow spheres is loose,the layer spacing and specific surface area are 18 nm and 59.81 m^(2)/g,respectively.When the DVB content is 0.3 mL,the hollow spheres have rough morphology and dense shell,the layer spacing and specific surface area are 35 nm and 61.63 m^(2)/g,respectively.With the increase of layer spacing,the thermal conductivity of double-ring structure HSN decreases and could be as low as 0.0252 W/(m·K).Double-ring structure HSN can effectively reduce the thermal conductivity of the coating.The thermal conductivity could be reduced by 85%as the dosage is 8%.The double-ring structure HSN has great application potential in the field of thermal insulation.