Rheological Properties of Silica Suspensions and Visualization of the Network Structures

二氧化硅悬浮液的流变特性和网络结构的可视化

• 批准号: 09650985
• 负责人: KOSEKI Kenichi
• 金额: $ 2.18万
• 依托单位: Chiba University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650985/
• 关键词: Network Structure; Silica Suspension; Viscoelastic Properties; Rheology; Photopolymerization; TEM

Fumed silica was dispersed in acrylate monomer by a roll mill. The silica aerosil (A200 ; Degussa Co.) was used for dispersed particle. The diameter and the density of powder were 12nm and 2.2g/cm^3, respectively. Photosensitive disperse medium was two functional acrylate monomer sensitized with photosensitive radical generator. Dynamic viscoelastic properties were measured by computer aided rheometer with a cone and plate geometry. All measurements were carried out at 25ﾟC.All suspension show typical shear thinning. We can deduce that the flocculated network structure depending on the concentration is broken down by steady shearing. The dependence of on the angular frequency without steady shear flow shows the characteristics of a concentrated suspension, namely the G' is independent of this frequency. After applying steady shear, the viscous film samples were polymerized by UV irradiation for fixing the structure. The results showed that the formation or deformation of the network structure by shearing estimated from the rheologycal behaviors of silica suspension was consistent with the TEM observation.

通过辊磨机将气相二氧化硅分散在丙烯酸酯单体中。将二氧化硅气溶胶（A200 ; Degussa Co.）用于分散颗粒。粉体的粒径为12 nm，密度为2.2g/cm ~ 3。光敏分散介质是用光敏自由基发生剂敏化的双官能丙烯酸酯单体。动态粘弹性能的测定是通过计算机辅助流变仪与锥板的几何形状。所有测量均在25 ℃下进行。所有悬浮液均显示出典型的剪切稀化。由此可以推断，稳态剪切作用破坏了依赖于浓度的絮凝网络结构。在没有稳定剪切流的情况下，对角频率的依赖性表明了浓悬浮液的特性，即G'与该频率无关。在施加稳定剪切后，通过UV照射聚合粘性膜样品以固定结构。结果表明，根据白炭黑悬浮液的流变行为推测的剪切作用下网络结构的形成或变形与透射电镜观察结果一致。