摘要：以Na₂SiO₃·9H₂O为原料,浓H₂SO₄为酸试剂,采用化学沉淀法制备纳米二氧化硅,讨论Na₂SiO₃浓度、搅拌速度、pH值、分散剂Na₂SO₄和表面活性剂聚乙二醇等因素对产物特性的影响,并用红外光谱、透射电镜、扫描电镜和X射线衍射等分析手段对二氧化硅纳米颗粒进行结构和形貌表征。利用本体聚合法制备了聚甲基丙烯酸甲酯-纳米二氧化硅复合材料,研究纳米二氧化硅颗粒对聚甲基丙烯酸甲酯材料力学性能的增强作用以及透光度的影响。结果表明:二氧化硅纳米粒子呈球形,粒径在50~100 nm范围内、分布均匀、呈无定形;填充纳米二氧化硅的复合材料的冲击强度和弯曲强度明显提高。

关键词： 纳米颗粒;二氧化硅;纳米复合材料

Abstract：Silica nano-particles were prepared via chemical precipitation using Na₂SiO₃·9H₂O and H₂SO₄. The effects of several technical factors on the properties of silica powders， such as Na₂SiO₃ concentrations， pH， agitation speed， dispersant Na₂SO₄ and surfactant PEG were studied. FT-IR， TEM， SEM and XRD were used to characterize the structure and morphology of the silica powders. The polymethylmethacrylate （PMMA） -silica nano-composites were prepared by in-situ bulk polymerization after silica nano-particles mixing with methylmethacrylate （MMA） monomer through ball milling. Finally， the reinforcing effect and the transparence of PMMA slices of silica nano-particles on PMMA were also investigated. The results showed that the as-prepared SiO₂ particles were amorphous， spherical with uniform size distribution and the particles size could be controlled in the range from 50 to l00 nm. The impact strength and flexural strength of the composite materials filled SiO₂ nano-particles was improved obviously. 

Key words： nano-particles； silica； nano-composites